1 //! Safe wrappers around functions found in libc "unistd.h" header
2
3 #[cfg(not(target_os = "redox"))]
4 use cfg_if::cfg_if;
5 use crate::errno::{self, Errno};
6 use crate::{Error, Result, NixPath};
7 #[cfg(not(target_os = "redox"))]
8 use crate::fcntl::{AtFlags, at_rawfd};
9 use crate::fcntl::{FdFlag, OFlag, fcntl};
10 use crate::fcntl::FcntlArg::F_SETFD;
11 use libc::{self, c_char, c_void, c_int, c_long, c_uint, size_t, pid_t, off_t,
12 uid_t, gid_t, mode_t, PATH_MAX};
13 use std::{fmt, mem, ptr};
14 use std::convert::Infallible;
15 use std::ffi::{CStr, CString, OsString};
16 #[cfg(not(target_os = "redox"))]
17 use std::ffi::{OsStr};
18 use std::os::unix::ffi::OsStringExt;
19 #[cfg(not(target_os = "redox"))]
20 use std::os::unix::ffi::OsStrExt;
21 use std::os::unix::io::RawFd;
22 use std::path::PathBuf;
23 use crate::sys::stat::Mode;
24
25 #[cfg(any(target_os = "android", target_os = "linux"))]
26 pub use self::pivot_root::*;
27
28 #[cfg(any(target_os = "android", target_os = "freebsd",
29 target_os = "linux", target_os = "openbsd"))]
30 pub use self::setres::*;
31
32 /// User identifier
33 ///
34 /// Newtype pattern around `uid_t` (which is just alias). It prevents bugs caused by accidentally
35 /// passing wrong value.
36 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
37 pub struct Uid(uid_t);
38
39 impl Uid {
40 /// Creates `Uid` from raw `uid_t`.
from_raw(uid: uid_t) -> Self41 pub fn from_raw(uid: uid_t) -> Self {
42 Uid(uid)
43 }
44
45 /// Returns Uid of calling process. This is practically a more Rusty alias for `getuid`.
current() -> Self46 pub fn current() -> Self {
47 getuid()
48 }
49
50 /// Returns effective Uid of calling process. This is practically a more Rusty alias for `geteuid`.
effective() -> Self51 pub fn effective() -> Self {
52 geteuid()
53 }
54
55 /// Returns true if the `Uid` represents privileged user - root. (If it equals zero.)
is_root(self) -> bool56 pub fn is_root(self) -> bool {
57 self == ROOT
58 }
59
60 /// Get the raw `uid_t` wrapped by `self`.
as_raw(self) -> uid_t61 pub fn as_raw(self) -> uid_t {
62 self.0
63 }
64 }
65
66 impl From<Uid> for uid_t {
from(uid: Uid) -> Self67 fn from(uid: Uid) -> Self {
68 uid.0
69 }
70 }
71
72 impl fmt::Display for Uid {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result73 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
74 fmt::Display::fmt(&self.0, f)
75 }
76 }
77
78 /// Constant for UID = 0
79 pub const ROOT: Uid = Uid(0);
80
81 /// Group identifier
82 ///
83 /// Newtype pattern around `gid_t` (which is just alias). It prevents bugs caused by accidentally
84 /// passing wrong value.
85 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
86 pub struct Gid(gid_t);
87
88 impl Gid {
89 /// Creates `Gid` from raw `gid_t`.
from_raw(gid: gid_t) -> Self90 pub fn from_raw(gid: gid_t) -> Self {
91 Gid(gid)
92 }
93
94 /// Returns Gid of calling process. This is practically a more Rusty alias for `getgid`.
current() -> Self95 pub fn current() -> Self {
96 getgid()
97 }
98
99 /// Returns effective Gid of calling process. This is practically a more Rusty alias for `getegid`.
effective() -> Self100 pub fn effective() -> Self {
101 getegid()
102 }
103
104 /// Get the raw `gid_t` wrapped by `self`.
as_raw(self) -> gid_t105 pub fn as_raw(self) -> gid_t {
106 self.0
107 }
108 }
109
110 impl From<Gid> for gid_t {
from(gid: Gid) -> Self111 fn from(gid: Gid) -> Self {
112 gid.0
113 }
114 }
115
116 impl fmt::Display for Gid {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result117 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
118 fmt::Display::fmt(&self.0, f)
119 }
120 }
121
122 /// Process identifier
123 ///
124 /// Newtype pattern around `pid_t` (which is just alias). It prevents bugs caused by accidentally
125 /// passing wrong value.
126 #[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
127 pub struct Pid(pid_t);
128
129 impl Pid {
130 /// Creates `Pid` from raw `pid_t`.
from_raw(pid: pid_t) -> Self131 pub fn from_raw(pid: pid_t) -> Self {
132 Pid(pid)
133 }
134
135 /// Returns PID of calling process
this() -> Self136 pub fn this() -> Self {
137 getpid()
138 }
139
140 /// Returns PID of parent of calling process
parent() -> Self141 pub fn parent() -> Self {
142 getppid()
143 }
144
145 /// Get the raw `pid_t` wrapped by `self`.
as_raw(self) -> pid_t146 pub fn as_raw(self) -> pid_t {
147 self.0
148 }
149 }
150
151 impl From<Pid> for pid_t {
from(pid: Pid) -> Self152 fn from(pid: Pid) -> Self {
153 pid.0
154 }
155 }
156
157 impl fmt::Display for Pid {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result158 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
159 fmt::Display::fmt(&self.0, f)
160 }
161 }
162
163
164 /// Represents the successful result of calling `fork`
165 ///
166 /// When `fork` is called, the process continues execution in the parent process
167 /// and in the new child. This return type can be examined to determine whether
168 /// you are now executing in the parent process or in the child.
169 #[derive(Clone, Copy, Debug)]
170 pub enum ForkResult {
171 Parent { child: Pid },
172 Child,
173 }
174
175 impl ForkResult {
176
177 /// Return `true` if this is the child process of the `fork()`
178 #[inline]
is_child(self) -> bool179 pub fn is_child(self) -> bool {
180 match self {
181 ForkResult::Child => true,
182 _ => false
183 }
184 }
185
186 /// Returns `true` if this is the parent process of the `fork()`
187 #[inline]
is_parent(self) -> bool188 pub fn is_parent(self) -> bool {
189 !self.is_child()
190 }
191 }
192
193 /// Create a new child process duplicating the parent process ([see
194 /// fork(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/fork.html)).
195 ///
196 /// After calling the fork system call (successfully) two processes will
197 /// be created that are identical with the exception of their pid and the
198 /// return value of this function. As an example:
199 ///
200 /// ```no_run
201 /// use nix::unistd::{fork, ForkResult};
202 ///
203 /// match unsafe{fork()} {
204 /// Ok(ForkResult::Parent { child, .. }) => {
205 /// println!("Continuing execution in parent process, new child has pid: {}", child);
206 /// }
207 /// Ok(ForkResult::Child) => println!("I'm a new child process"),
208 /// Err(_) => println!("Fork failed"),
209 /// }
210 /// ```
211 ///
212 /// This will print something like the following (order indeterministic). The
213 /// thing to note is that you end up with two processes continuing execution
214 /// immediately after the fork call but with different match arms.
215 ///
216 /// ```text
217 /// Continuing execution in parent process, new child has pid: 1234
218 /// I'm a new child process
219 /// ```
220 ///
221 /// # Safety
222 ///
223 /// In a multithreaded program, only [async-signal-safe] functions like `pause`
224 /// and `_exit` may be called by the child (the parent isn't restricted). Note
225 /// that memory allocation may **not** be async-signal-safe and thus must be
226 /// prevented.
227 ///
228 /// Those functions are only a small subset of your operating system's API, so
229 /// special care must be taken to only invoke code you can control and audit.
230 ///
231 /// [async-signal-safe]: http://man7.org/linux/man-pages/man7/signal-safety.7.html
232 #[inline]
fork() -> Result<ForkResult>233 pub unsafe fn fork() -> Result<ForkResult> {
234 use self::ForkResult::*;
235 let res = libc::fork();
236
237 Errno::result(res).map(|res| match res {
238 0 => Child,
239 res => Parent { child: Pid(res) },
240 })
241 }
242
243 /// Get the pid of this process (see
244 /// [getpid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getpid.html)).
245 ///
246 /// Since you are running code, there is always a pid to return, so there
247 /// is no error case that needs to be handled.
248 #[inline]
getpid() -> Pid249 pub fn getpid() -> Pid {
250 Pid(unsafe { libc::getpid() })
251 }
252
253 /// Get the pid of this processes' parent (see
254 /// [getpid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getppid.html)).
255 ///
256 /// There is always a parent pid to return, so there is no error case that needs
257 /// to be handled.
258 #[inline]
getppid() -> Pid259 pub fn getppid() -> Pid {
260 Pid(unsafe { libc::getppid() }) // no error handling, according to man page: "These functions are always successful."
261 }
262
263 /// Set a process group ID (see
264 /// [setpgid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/setpgid.html)).
265 ///
266 /// Set the process group id (PGID) of a particular process. If a pid of zero
267 /// is specified, then the pid of the calling process is used. Process groups
268 /// may be used to group together a set of processes in order for the OS to
269 /// apply some operations across the group.
270 ///
271 /// `setsid()` may be used to create a new process group.
272 #[inline]
setpgid(pid: Pid, pgid: Pid) -> Result<()>273 pub fn setpgid(pid: Pid, pgid: Pid) -> Result<()> {
274 let res = unsafe { libc::setpgid(pid.into(), pgid.into()) };
275 Errno::result(res).map(drop)
276 }
277 #[inline]
getpgid(pid: Option<Pid>) -> Result<Pid>278 pub fn getpgid(pid: Option<Pid>) -> Result<Pid> {
279 let res = unsafe { libc::getpgid(pid.unwrap_or(Pid(0)).into()) };
280 Errno::result(res).map(Pid)
281 }
282
283 /// Create new session and set process group id (see
284 /// [setsid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/setsid.html)).
285 #[inline]
setsid() -> Result<Pid>286 pub fn setsid() -> Result<Pid> {
287 Errno::result(unsafe { libc::setsid() }).map(Pid)
288 }
289
290 /// Get the process group ID of a session leader
291 /// [getsid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getsid.html).
292 ///
293 /// Obtain the process group ID of the process that is the session leader of the process specified
294 /// by pid. If pid is zero, it specifies the calling process.
295 #[inline]
296 #[cfg(not(target_os = "redox"))]
getsid(pid: Option<Pid>) -> Result<Pid>297 pub fn getsid(pid: Option<Pid>) -> Result<Pid> {
298 let res = unsafe { libc::getsid(pid.unwrap_or(Pid(0)).into()) };
299 Errno::result(res).map(Pid)
300 }
301
302
303 /// Get the terminal foreground process group (see
304 /// [tcgetpgrp(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/tcgetpgrp.html)).
305 ///
306 /// Get the group process id (GPID) of the foreground process group on the
307 /// terminal associated to file descriptor (FD).
308 #[inline]
tcgetpgrp(fd: c_int) -> Result<Pid>309 pub fn tcgetpgrp(fd: c_int) -> Result<Pid> {
310 let res = unsafe { libc::tcgetpgrp(fd) };
311 Errno::result(res).map(Pid)
312 }
313 /// Set the terminal foreground process group (see
314 /// [tcgetpgrp(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/tcsetpgrp.html)).
315 ///
316 /// Get the group process id (PGID) to the foreground process group on the
317 /// terminal associated to file descriptor (FD).
318 #[inline]
tcsetpgrp(fd: c_int, pgrp: Pid) -> Result<()>319 pub fn tcsetpgrp(fd: c_int, pgrp: Pid) -> Result<()> {
320 let res = unsafe { libc::tcsetpgrp(fd, pgrp.into()) };
321 Errno::result(res).map(drop)
322 }
323
324
325 /// Get the group id of the calling process (see
326 ///[getpgrp(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getpgrp.html)).
327 ///
328 /// Get the process group id (PGID) of the calling process.
329 /// According to the man page it is always successful.
330 #[inline]
getpgrp() -> Pid331 pub fn getpgrp() -> Pid {
332 Pid(unsafe { libc::getpgrp() })
333 }
334
335 /// Get the caller's thread ID (see
336 /// [gettid(2)](http://man7.org/linux/man-pages/man2/gettid.2.html).
337 ///
338 /// This function is only available on Linux based systems. In a single
339 /// threaded process, the main thread will have the same ID as the process. In
340 /// a multithreaded process, each thread will have a unique thread id but the
341 /// same process ID.
342 ///
343 /// No error handling is required as a thread id should always exist for any
344 /// process, even if threads are not being used.
345 #[cfg(any(target_os = "linux", target_os = "android"))]
346 #[inline]
gettid() -> Pid347 pub fn gettid() -> Pid {
348 Pid(unsafe { libc::syscall(libc::SYS_gettid) as pid_t })
349 }
350
351 /// Create a copy of the specified file descriptor (see
352 /// [dup(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/dup.html)).
353 ///
354 /// The new file descriptor will be have a new index but refer to the same
355 /// resource as the old file descriptor and the old and new file descriptors may
356 /// be used interchangeably. The new and old file descriptor share the same
357 /// underlying resource, offset, and file status flags. The actual index used
358 /// for the file descriptor will be the lowest fd index that is available.
359 ///
360 /// The two file descriptors do not share file descriptor flags (e.g. `OFlag::FD_CLOEXEC`).
361 #[inline]
dup(oldfd: RawFd) -> Result<RawFd>362 pub fn dup(oldfd: RawFd) -> Result<RawFd> {
363 let res = unsafe { libc::dup(oldfd) };
364
365 Errno::result(res)
366 }
367
368 /// Create a copy of the specified file descriptor using the specified fd (see
369 /// [dup(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/dup.html)).
370 ///
371 /// This function behaves similar to `dup()` except that it will try to use the
372 /// specified fd instead of allocating a new one. See the man pages for more
373 /// detail on the exact behavior of this function.
374 #[inline]
dup2(oldfd: RawFd, newfd: RawFd) -> Result<RawFd>375 pub fn dup2(oldfd: RawFd, newfd: RawFd) -> Result<RawFd> {
376 let res = unsafe { libc::dup2(oldfd, newfd) };
377
378 Errno::result(res)
379 }
380
381 /// Create a new copy of the specified file descriptor using the specified fd
382 /// and flags (see [dup(2)](http://man7.org/linux/man-pages/man2/dup.2.html)).
383 ///
384 /// This function behaves similar to `dup2()` but allows for flags to be
385 /// specified.
dup3(oldfd: RawFd, newfd: RawFd, flags: OFlag) -> Result<RawFd>386 pub fn dup3(oldfd: RawFd, newfd: RawFd, flags: OFlag) -> Result<RawFd> {
387 dup3_polyfill(oldfd, newfd, flags)
388 }
389
390 #[inline]
dup3_polyfill(oldfd: RawFd, newfd: RawFd, flags: OFlag) -> Result<RawFd>391 fn dup3_polyfill(oldfd: RawFd, newfd: RawFd, flags: OFlag) -> Result<RawFd> {
392 if oldfd == newfd {
393 return Err(Error::Sys(Errno::EINVAL));
394 }
395
396 let fd = dup2(oldfd, newfd)?;
397
398 if flags.contains(OFlag::O_CLOEXEC) {
399 if let Err(e) = fcntl(fd, F_SETFD(FdFlag::FD_CLOEXEC)) {
400 let _ = close(fd);
401 return Err(e);
402 }
403 }
404
405 Ok(fd)
406 }
407
408 /// Change the current working directory of the calling process (see
409 /// [chdir(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/chdir.html)).
410 ///
411 /// This function may fail in a number of different scenarios. See the man
412 /// pages for additional details on possible failure cases.
413 #[inline]
chdir<P: ?Sized + NixPath>(path: &P) -> Result<()>414 pub fn chdir<P: ?Sized + NixPath>(path: &P) -> Result<()> {
415 let res = path.with_nix_path(|cstr| {
416 unsafe { libc::chdir(cstr.as_ptr()) }
417 })?;
418
419 Errno::result(res).map(drop)
420 }
421
422 /// Change the current working directory of the process to the one
423 /// given as an open file descriptor (see
424 /// [fchdir(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/fchdir.html)).
425 ///
426 /// This function may fail in a number of different scenarios. See the man
427 /// pages for additional details on possible failure cases.
428 #[inline]
fchdir(dirfd: RawFd) -> Result<()>429 pub fn fchdir(dirfd: RawFd) -> Result<()> {
430 let res = unsafe { libc::fchdir(dirfd) };
431
432 Errno::result(res).map(drop)
433 }
434
435 /// Creates new directory `path` with access rights `mode`. (see [mkdir(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/mkdir.html))
436 ///
437 /// # Errors
438 ///
439 /// There are several situations where mkdir might fail:
440 ///
441 /// - current user has insufficient rights in the parent directory
442 /// - the path already exists
443 /// - the path name is too long (longer than `PATH_MAX`, usually 4096 on linux, 1024 on OS X)
444 ///
445 /// # Example
446 ///
447 /// ```rust
448 /// use nix::unistd;
449 /// use nix::sys::stat;
450 /// use tempfile::tempdir;
451 ///
452 /// fn main() {
453 /// let tmp_dir1 = tempdir().unwrap();
454 /// let tmp_dir2 = tmp_dir1.path().join("new_dir");
455 ///
456 /// // create new directory and give read, write and execute rights to the owner
457 /// match unistd::mkdir(&tmp_dir2, stat::Mode::S_IRWXU) {
458 /// Ok(_) => println!("created {:?}", tmp_dir2),
459 /// Err(err) => println!("Error creating directory: {}", err),
460 /// }
461 /// }
462 /// ```
463 #[inline]
mkdir<P: ?Sized + NixPath>(path: &P, mode: Mode) -> Result<()>464 pub fn mkdir<P: ?Sized + NixPath>(path: &P, mode: Mode) -> Result<()> {
465 let res = path.with_nix_path(|cstr| {
466 unsafe { libc::mkdir(cstr.as_ptr(), mode.bits() as mode_t) }
467 })?;
468
469 Errno::result(res).map(drop)
470 }
471
472 /// Creates new fifo special file (named pipe) with path `path` and access rights `mode`.
473 ///
474 /// # Errors
475 ///
476 /// There are several situations where mkfifo might fail:
477 ///
478 /// - current user has insufficient rights in the parent directory
479 /// - the path already exists
480 /// - the path name is too long (longer than `PATH_MAX`, usually 4096 on linux, 1024 on OS X)
481 ///
482 /// For a full list consult
483 /// [posix specification](http://pubs.opengroup.org/onlinepubs/9699919799/functions/mkfifo.html)
484 ///
485 /// # Example
486 ///
487 /// ```rust
488 /// use nix::unistd;
489 /// use nix::sys::stat;
490 /// use tempfile::tempdir;
491 ///
492 /// fn main() {
493 /// let tmp_dir = tempdir().unwrap();
494 /// let fifo_path = tmp_dir.path().join("foo.pipe");
495 ///
496 /// // create new fifo and give read, write and execute rights to the owner
497 /// match unistd::mkfifo(&fifo_path, stat::Mode::S_IRWXU) {
498 /// Ok(_) => println!("created {:?}", fifo_path),
499 /// Err(err) => println!("Error creating fifo: {}", err),
500 /// }
501 /// }
502 /// ```
503 #[inline]
504 #[cfg(not(target_os = "redox"))] // RedoxFS does not support fifo yet
mkfifo<P: ?Sized + NixPath>(path: &P, mode: Mode) -> Result<()>505 pub fn mkfifo<P: ?Sized + NixPath>(path: &P, mode: Mode) -> Result<()> {
506 let res = path.with_nix_path(|cstr| {
507 unsafe { libc::mkfifo(cstr.as_ptr(), mode.bits() as mode_t) }
508 })?;
509
510 Errno::result(res).map(drop)
511 }
512
513 /// Creates new fifo special file (named pipe) with path `path` and access rights `mode`.
514 ///
515 /// If `dirfd` has a value, then `path` is relative to directory associated with the file descriptor.
516 ///
517 /// If `dirfd` is `None`, then `path` is relative to the current working directory.
518 ///
519 /// # References
520 ///
521 /// [mkfifoat(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/mkfifoat.html).
522 // mkfifoat is not implemented in OSX or android
523 #[inline]
524 #[cfg(not(any(
525 target_os = "macos", target_os = "ios",
526 target_os = "android", target_os = "redox")))]
mkfifoat<P: ?Sized + NixPath>(dirfd: Option<RawFd>, path: &P, mode: Mode) -> Result<()>527 pub fn mkfifoat<P: ?Sized + NixPath>(dirfd: Option<RawFd>, path: &P, mode: Mode) -> Result<()> {
528 let res = path.with_nix_path(|cstr| unsafe {
529 libc::mkfifoat(at_rawfd(dirfd), cstr.as_ptr(), mode.bits() as mode_t)
530 })?;
531
532 Errno::result(res).map(drop)
533 }
534
535 /// Creates a symbolic link at `path2` which points to `path1`.
536 ///
537 /// If `dirfd` has a value, then `path2` is relative to directory associated
538 /// with the file descriptor.
539 ///
540 /// If `dirfd` is `None`, then `path2` is relative to the current working
541 /// directory. This is identical to `libc::symlink(path1, path2)`.
542 ///
543 /// See also [symlinkat(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/symlinkat.html).
544 #[cfg(not(target_os = "redox"))]
symlinkat<P1: ?Sized + NixPath, P2: ?Sized + NixPath>( path1: &P1, dirfd: Option<RawFd>, path2: &P2) -> Result<()>545 pub fn symlinkat<P1: ?Sized + NixPath, P2: ?Sized + NixPath>(
546 path1: &P1,
547 dirfd: Option<RawFd>,
548 path2: &P2) -> Result<()> {
549 let res =
550 path1.with_nix_path(|path1| {
551 path2.with_nix_path(|path2| {
552 unsafe {
553 libc::symlinkat(
554 path1.as_ptr(),
555 dirfd.unwrap_or(libc::AT_FDCWD),
556 path2.as_ptr()
557 )
558 }
559 })
560 })??;
561 Errno::result(res).map(drop)
562 }
563
564 // Double the buffer capacity up to limit. In case it already has
565 // reached the limit, return Errno::ERANGE.
reserve_double_buffer_size<T>(buf: &mut Vec<T>, limit: usize) -> Result<()>566 fn reserve_double_buffer_size<T>(buf: &mut Vec<T>, limit: usize) -> Result<()> {
567 use std::cmp::min;
568
569 if buf.capacity() >= limit {
570 return Err(Error::Sys(Errno::ERANGE))
571 }
572
573 let capacity = min(buf.capacity() * 2, limit);
574 buf.reserve(capacity);
575
576 Ok(())
577 }
578
579 /// Returns the current directory as a `PathBuf`
580 ///
581 /// Err is returned if the current user doesn't have the permission to read or search a component
582 /// of the current path.
583 ///
584 /// # Example
585 ///
586 /// ```rust
587 /// use nix::unistd;
588 ///
589 /// fn main() {
590 /// // assume that we are allowed to get current directory
591 /// let dir = unistd::getcwd().unwrap();
592 /// println!("The current directory is {:?}", dir);
593 /// }
594 /// ```
595 #[inline]
getcwd() -> Result<PathBuf>596 pub fn getcwd() -> Result<PathBuf> {
597 let mut buf = Vec::with_capacity(512);
598 loop {
599 unsafe {
600 let ptr = buf.as_mut_ptr() as *mut c_char;
601
602 // The buffer must be large enough to store the absolute pathname plus
603 // a terminating null byte, or else null is returned.
604 // To safely handle this we start with a reasonable size (512 bytes)
605 // and double the buffer size upon every error
606 if !libc::getcwd(ptr, buf.capacity()).is_null() {
607 let len = CStr::from_ptr(buf.as_ptr() as *const c_char).to_bytes().len();
608 buf.set_len(len);
609 buf.shrink_to_fit();
610 return Ok(PathBuf::from(OsString::from_vec(buf)));
611 } else {
612 let error = Errno::last();
613 // ERANGE means buffer was too small to store directory name
614 if error != Errno::ERANGE {
615 return Err(Error::Sys(error));
616 }
617 }
618
619 // Trigger the internal buffer resizing logic.
620 reserve_double_buffer_size(&mut buf, PATH_MAX as usize)?;
621 }
622 }
623 }
624
625 /// Computes the raw UID and GID values to pass to a `*chown` call.
chown_raw_ids(owner: Option<Uid>, group: Option<Gid>) -> (libc::uid_t, libc::gid_t)626 fn chown_raw_ids(owner: Option<Uid>, group: Option<Gid>) -> (libc::uid_t, libc::gid_t) {
627 // According to the POSIX specification, -1 is used to indicate that owner and group
628 // are not to be changed. Since uid_t and gid_t are unsigned types, we have to wrap
629 // around to get -1.
630 let uid = owner.map(Into::into)
631 .unwrap_or_else(|| (0 as uid_t).wrapping_sub(1));
632 let gid = group.map(Into::into)
633 .unwrap_or_else(|| (0 as gid_t).wrapping_sub(1));
634 (uid, gid)
635 }
636
637 /// Change the ownership of the file at `path` to be owned by the specified
638 /// `owner` (user) and `group` (see
639 /// [chown(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/chown.html)).
640 ///
641 /// The owner/group for the provided path name will not be modified if `None` is
642 /// provided for that argument. Ownership change will be attempted for the path
643 /// only if `Some` owner/group is provided.
644 #[inline]
chown<P: ?Sized + NixPath>(path: &P, owner: Option<Uid>, group: Option<Gid>) -> Result<()>645 pub fn chown<P: ?Sized + NixPath>(path: &P, owner: Option<Uid>, group: Option<Gid>) -> Result<()> {
646 let res = path.with_nix_path(|cstr| {
647 let (uid, gid) = chown_raw_ids(owner, group);
648 unsafe { libc::chown(cstr.as_ptr(), uid, gid) }
649 })?;
650
651 Errno::result(res).map(drop)
652 }
653
654 /// Change the ownership of the file referred to by the open file descriptor `fd` to be owned by
655 /// the specified `owner` (user) and `group` (see
656 /// [fchown(2)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/fchown.html)).
657 ///
658 /// The owner/group for the provided file will not be modified if `None` is
659 /// provided for that argument. Ownership change will be attempted for the path
660 /// only if `Some` owner/group is provided.
661 #[inline]
fchown(fd: RawFd, owner: Option<Uid>, group: Option<Gid>) -> Result<()>662 pub fn fchown(fd: RawFd, owner: Option<Uid>, group: Option<Gid>) -> Result<()> {
663 let (uid, gid) = chown_raw_ids(owner, group);
664 let res = unsafe { libc::fchown(fd, uid, gid) };
665 Errno::result(res).map(drop)
666 }
667
668 /// Flags for `fchownat` function.
669 #[derive(Clone, Copy, Debug)]
670 pub enum FchownatFlags {
671 FollowSymlink,
672 NoFollowSymlink,
673 }
674
675 /// Change the ownership of the file at `path` to be owned by the specified
676 /// `owner` (user) and `group`.
677 ///
678 /// The owner/group for the provided path name will not be modified if `None` is
679 /// provided for that argument. Ownership change will be attempted for the path
680 /// only if `Some` owner/group is provided.
681 ///
682 /// The file to be changed is determined relative to the directory associated
683 /// with the file descriptor `dirfd` or the current working directory
684 /// if `dirfd` is `None`.
685 ///
686 /// If `flag` is `FchownatFlags::NoFollowSymlink` and `path` names a symbolic link,
687 /// then the mode of the symbolic link is changed.
688 ///
689 /// `fchownat(None, path, mode, FchownatFlags::NoFollowSymlink)` is identical to
690 /// a call `libc::lchown(path, mode)`. That's why `lchmod` is unimplemented in
691 /// the `nix` crate.
692 ///
693 /// # References
694 ///
695 /// [fchownat(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/fchownat.html).
696 #[cfg(not(target_os = "redox"))]
fchownat<P: ?Sized + NixPath>( dirfd: Option<RawFd>, path: &P, owner: Option<Uid>, group: Option<Gid>, flag: FchownatFlags, ) -> Result<()>697 pub fn fchownat<P: ?Sized + NixPath>(
698 dirfd: Option<RawFd>,
699 path: &P,
700 owner: Option<Uid>,
701 group: Option<Gid>,
702 flag: FchownatFlags,
703 ) -> Result<()> {
704 let atflag =
705 match flag {
706 FchownatFlags::FollowSymlink => AtFlags::empty(),
707 FchownatFlags::NoFollowSymlink => AtFlags::AT_SYMLINK_NOFOLLOW,
708 };
709 let res = path.with_nix_path(|cstr| unsafe {
710 let (uid, gid) = chown_raw_ids(owner, group);
711 libc::fchownat(at_rawfd(dirfd), cstr.as_ptr(), uid, gid,
712 atflag.bits() as libc::c_int)
713 })?;
714
715 Errno::result(res).map(drop)
716 }
717
to_exec_array<S: AsRef<CStr>>(args: &[S]) -> Vec<*const c_char>718 fn to_exec_array<S: AsRef<CStr>>(args: &[S]) -> Vec<*const c_char> {
719 use std::iter::once;
720 args.iter().map(|s| s.as_ref().as_ptr()).chain(once(ptr::null())).collect()
721 }
722
723 /// Replace the current process image with a new one (see
724 /// [exec(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html)).
725 ///
726 /// See the `::nix::unistd::execve` system call for additional details. `execv`
727 /// performs the same action but does not allow for customization of the
728 /// environment for the new process.
729 #[inline]
execv<S: AsRef<CStr>>(path: &CStr, argv: &[S]) -> Result<Infallible>730 pub fn execv<S: AsRef<CStr>>(path: &CStr, argv: &[S]) -> Result<Infallible> {
731 let args_p = to_exec_array(argv);
732
733 unsafe {
734 libc::execv(path.as_ptr(), args_p.as_ptr())
735 };
736
737 Err(Error::Sys(Errno::last()))
738 }
739
740
741 /// Replace the current process image with a new one (see
742 /// [execve(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html)).
743 ///
744 /// The execve system call allows for another process to be "called" which will
745 /// replace the current process image. That is, this process becomes the new
746 /// command that is run. On success, this function will not return. Instead,
747 /// the new program will run until it exits.
748 ///
749 /// `::nix::unistd::execv` and `::nix::unistd::execve` take as arguments a slice
750 /// of `::std::ffi::CString`s for `args` and `env` (for `execve`). Each element
751 /// in the `args` list is an argument to the new process. Each element in the
752 /// `env` list should be a string in the form "key=value".
753 #[inline]
execve<SA: AsRef<CStr>, SE: AsRef<CStr>>(path: &CStr, args: &[SA], env: &[SE]) -> Result<Infallible>754 pub fn execve<SA: AsRef<CStr>, SE: AsRef<CStr>>(path: &CStr, args: &[SA], env: &[SE]) -> Result<Infallible> {
755 let args_p = to_exec_array(args);
756 let env_p = to_exec_array(env);
757
758 unsafe {
759 libc::execve(path.as_ptr(), args_p.as_ptr(), env_p.as_ptr())
760 };
761
762 Err(Error::Sys(Errno::last()))
763 }
764
765 /// Replace the current process image with a new one and replicate shell `PATH`
766 /// searching behavior (see
767 /// [exec(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html)).
768 ///
769 /// See `::nix::unistd::execve` for additional details. `execvp` behaves the
770 /// same as execv except that it will examine the `PATH` environment variables
771 /// for file names not specified with a leading slash. For example, `execv`
772 /// would not work if "bash" was specified for the path argument, but `execvp`
773 /// would assuming that a bash executable was on the system `PATH`.
774 #[inline]
execvp<S: AsRef<CStr>>(filename: &CStr, args: &[S]) -> Result<Infallible>775 pub fn execvp<S: AsRef<CStr>>(filename: &CStr, args: &[S]) -> Result<Infallible> {
776 let args_p = to_exec_array(args);
777
778 unsafe {
779 libc::execvp(filename.as_ptr(), args_p.as_ptr())
780 };
781
782 Err(Error::Sys(Errno::last()))
783 }
784
785 /// Replace the current process image with a new one and replicate shell `PATH`
786 /// searching behavior (see
787 /// [`execvpe(3)`](http://man7.org/linux/man-pages/man3/exec.3.html)).
788 ///
789 /// This functions like a combination of `execvp(2)` and `execve(2)` to pass an
790 /// environment and have a search path. See these two for additional
791 /// information.
792 #[cfg(any(target_os = "haiku",
793 target_os = "linux",
794 target_os = "openbsd"))]
execvpe<SA: AsRef<CStr>, SE: AsRef<CStr>>(filename: &CStr, args: &[SA], env: &[SE]) -> Result<Infallible>795 pub fn execvpe<SA: AsRef<CStr>, SE: AsRef<CStr>>(filename: &CStr, args: &[SA], env: &[SE]) -> Result<Infallible> {
796 let args_p = to_exec_array(args);
797 let env_p = to_exec_array(env);
798
799 unsafe {
800 libc::execvpe(filename.as_ptr(), args_p.as_ptr(), env_p.as_ptr())
801 };
802
803 Err(Error::Sys(Errno::last()))
804 }
805
806 /// Replace the current process image with a new one (see
807 /// [fexecve(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/fexecve.html)).
808 ///
809 /// The `fexecve` function allows for another process to be "called" which will
810 /// replace the current process image. That is, this process becomes the new
811 /// command that is run. On success, this function will not return. Instead,
812 /// the new program will run until it exits.
813 ///
814 /// This function is similar to `execve`, except that the program to be executed
815 /// is referenced as a file descriptor instead of a path.
816 // Note for NetBSD and OpenBSD: although rust-lang/libc includes it (under
817 // unix/bsd/netbsdlike/) fexecve is not currently implemented on NetBSD nor on
818 // OpenBSD.
819 #[cfg(any(target_os = "android",
820 target_os = "linux",
821 target_os = "freebsd"))]
822 #[inline]
fexecve<SA: AsRef<CStr> ,SE: AsRef<CStr>>(fd: RawFd, args: &[SA], env: &[SE]) -> Result<Infallible>823 pub fn fexecve<SA: AsRef<CStr> ,SE: AsRef<CStr>>(fd: RawFd, args: &[SA], env: &[SE]) -> Result<Infallible> {
824 let args_p = to_exec_array(args);
825 let env_p = to_exec_array(env);
826
827 unsafe {
828 libc::fexecve(fd, args_p.as_ptr(), env_p.as_ptr())
829 };
830
831 Err(Error::Sys(Errno::last()))
832 }
833
834 /// Execute program relative to a directory file descriptor (see
835 /// [execveat(2)](http://man7.org/linux/man-pages/man2/execveat.2.html)).
836 ///
837 /// The `execveat` function allows for another process to be "called" which will
838 /// replace the current process image. That is, this process becomes the new
839 /// command that is run. On success, this function will not return. Instead,
840 /// the new program will run until it exits.
841 ///
842 /// This function is similar to `execve`, except that the program to be executed
843 /// is referenced as a file descriptor to the base directory plus a path.
844 #[cfg(any(target_os = "android", target_os = "linux"))]
845 #[inline]
execveat<SA: AsRef<CStr>,SE: AsRef<CStr>>(dirfd: RawFd, pathname: &CStr, args: &[SA], env: &[SE], flags: super::fcntl::AtFlags) -> Result<Infallible>846 pub fn execveat<SA: AsRef<CStr>,SE: AsRef<CStr>>(dirfd: RawFd, pathname: &CStr, args: &[SA],
847 env: &[SE], flags: super::fcntl::AtFlags) -> Result<Infallible> {
848 let args_p = to_exec_array(args);
849 let env_p = to_exec_array(env);
850
851 unsafe {
852 libc::syscall(libc::SYS_execveat, dirfd, pathname.as_ptr(),
853 args_p.as_ptr(), env_p.as_ptr(), flags);
854 };
855
856 Err(Error::Sys(Errno::last()))
857 }
858
859 /// Daemonize this process by detaching from the controlling terminal (see
860 /// [daemon(3)](http://man7.org/linux/man-pages/man3/daemon.3.html)).
861 ///
862 /// When a process is launched it is typically associated with a parent and it,
863 /// in turn, by its controlling terminal/process. In order for a process to run
864 /// in the "background" it must daemonize itself by detaching itself. Under
865 /// posix, this is done by doing the following:
866 ///
867 /// 1. Parent process (this one) forks
868 /// 2. Parent process exits
869 /// 3. Child process continues to run.
870 ///
871 /// `nochdir`:
872 ///
873 /// * `nochdir = true`: The current working directory after daemonizing will
874 /// be the current working directory.
875 /// * `nochdir = false`: The current working directory after daemonizing will
876 /// be the root direcory, `/`.
877 ///
878 /// `noclose`:
879 ///
880 /// * `noclose = true`: The process' current stdin, stdout, and stderr file
881 /// descriptors will remain identical after daemonizing.
882 /// * `noclose = false`: The process' stdin, stdout, and stderr will point to
883 /// `/dev/null` after daemonizing.
884 #[cfg(any(target_os = "android",
885 target_os = "dragonfly",
886 target_os = "freebsd",
887 target_os = "linux",
888 target_os = "netbsd",
889 target_os = "openbsd"))]
daemon(nochdir: bool, noclose: bool) -> Result<()>890 pub fn daemon(nochdir: bool, noclose: bool) -> Result<()> {
891 let res = unsafe { libc::daemon(nochdir as c_int, noclose as c_int) };
892 Errno::result(res).map(drop)
893 }
894
895 /// Set the system host name (see
896 /// [sethostname(2)](http://man7.org/linux/man-pages/man2/gethostname.2.html)).
897 ///
898 /// Given a name, attempt to update the system host name to the given string.
899 /// On some systems, the host name is limited to as few as 64 bytes. An error
900 /// will be return if the name is not valid or the current process does not have
901 /// permissions to update the host name.
902 #[cfg(not(target_os = "redox"))]
sethostname<S: AsRef<OsStr>>(name: S) -> Result<()>903 pub fn sethostname<S: AsRef<OsStr>>(name: S) -> Result<()> {
904 // Handle some differences in type of the len arg across platforms.
905 cfg_if! {
906 if #[cfg(any(target_os = "dragonfly",
907 target_os = "freebsd",
908 target_os = "ios",
909 target_os = "macos", ))] {
910 type sethostname_len_t = c_int;
911 } else {
912 type sethostname_len_t = size_t;
913 }
914 }
915 let ptr = name.as_ref().as_bytes().as_ptr() as *const c_char;
916 let len = name.as_ref().len() as sethostname_len_t;
917
918 let res = unsafe { libc::sethostname(ptr, len) };
919 Errno::result(res).map(drop)
920 }
921
922 /// Get the host name and store it in the provided buffer, returning a pointer
923 /// the `CStr` in that buffer on success (see
924 /// [gethostname(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/gethostname.html)).
925 ///
926 /// This function call attempts to get the host name for the running system and
927 /// store it in a provided buffer. The buffer will be populated with bytes up
928 /// to the length of the provided slice including a NUL terminating byte. If
929 /// the hostname is longer than the length provided, no error will be provided.
930 /// The posix specification does not specify whether implementations will
931 /// null-terminate in this case, but the nix implementation will ensure that the
932 /// buffer is null terminated in this case.
933 ///
934 /// ```no_run
935 /// use nix::unistd;
936 ///
937 /// let mut buf = [0u8; 64];
938 /// let hostname_cstr = unistd::gethostname(&mut buf).expect("Failed getting hostname");
939 /// let hostname = hostname_cstr.to_str().expect("Hostname wasn't valid UTF-8");
940 /// println!("Hostname: {}", hostname);
941 /// ```
gethostname(buffer: &mut [u8]) -> Result<&CStr>942 pub fn gethostname(buffer: &mut [u8]) -> Result<&CStr> {
943 let ptr = buffer.as_mut_ptr() as *mut c_char;
944 let len = buffer.len() as size_t;
945
946 let res = unsafe { libc::gethostname(ptr, len) };
947 Errno::result(res).map(|_| {
948 buffer[len - 1] = 0; // ensure always null-terminated
949 unsafe { CStr::from_ptr(buffer.as_ptr() as *const c_char) }
950 })
951 }
952
953 /// Close a raw file descriptor
954 ///
955 /// Be aware that many Rust types implicitly close-on-drop, including
956 /// `std::fs::File`. Explicitly closing them with this method too can result in
957 /// a double-close condition, which can cause confusing `EBADF` errors in
958 /// seemingly unrelated code. Caveat programmer. See also
959 /// [close(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/close.html).
960 ///
961 /// # Examples
962 ///
963 /// ```no_run
964 /// use std::os::unix::io::AsRawFd;
965 /// use nix::unistd::close;
966 ///
967 /// fn main() {
968 /// let f = tempfile::tempfile().unwrap();
969 /// close(f.as_raw_fd()).unwrap(); // Bad! f will also close on drop!
970 /// }
971 /// ```
972 ///
973 /// ```rust
974 /// use std::os::unix::io::IntoRawFd;
975 /// use nix::unistd::close;
976 ///
977 /// fn main() {
978 /// let f = tempfile::tempfile().unwrap();
979 /// close(f.into_raw_fd()).unwrap(); // Good. into_raw_fd consumes f
980 /// }
981 /// ```
close(fd: RawFd) -> Result<()>982 pub fn close(fd: RawFd) -> Result<()> {
983 let res = unsafe { libc::close(fd) };
984 Errno::result(res).map(drop)
985 }
986
987 /// Read from a raw file descriptor.
988 ///
989 /// See also [read(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/read.html)
read(fd: RawFd, buf: &mut [u8]) -> Result<usize>990 pub fn read(fd: RawFd, buf: &mut [u8]) -> Result<usize> {
991 let res = unsafe { libc::read(fd, buf.as_mut_ptr() as *mut c_void, buf.len() as size_t) };
992
993 Errno::result(res).map(|r| r as usize)
994 }
995
996 /// Write to a raw file descriptor.
997 ///
998 /// See also [write(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/write.html)
write(fd: RawFd, buf: &[u8]) -> Result<usize>999 pub fn write(fd: RawFd, buf: &[u8]) -> Result<usize> {
1000 let res = unsafe { libc::write(fd, buf.as_ptr() as *const c_void, buf.len() as size_t) };
1001
1002 Errno::result(res).map(|r| r as usize)
1003 }
1004
1005 /// Directive that tells [`lseek`] and [`lseek64`] what the offset is relative to.
1006 ///
1007 /// [`lseek`]: ./fn.lseek.html
1008 /// [`lseek64`]: ./fn.lseek64.html
1009 #[repr(i32)]
1010 #[derive(Clone, Copy, Debug)]
1011 pub enum Whence {
1012 /// Specify an offset relative to the start of the file.
1013 SeekSet = libc::SEEK_SET,
1014 /// Specify an offset relative to the current file location.
1015 SeekCur = libc::SEEK_CUR,
1016 /// Specify an offset relative to the end of the file.
1017 SeekEnd = libc::SEEK_END,
1018 /// Specify an offset relative to the next location in the file greater than or
1019 /// equal to offset that contains some data. If offset points to
1020 /// some data, then the file offset is set to offset.
1021 #[cfg(any(target_os = "dragonfly", target_os = "freebsd", target_os = "linux"))]
1022 SeekData = libc::SEEK_DATA,
1023 /// Specify an offset relative to the next hole in the file greater than
1024 /// or equal to offset. If offset points into the middle of a hole, then
1025 /// the file offset should be set to offset. If there is no hole past offset,
1026 /// then the file offset should be adjusted to the end of the file (i.e., there
1027 /// is an implicit hole at the end of any file).
1028 #[cfg(any(target_os = "dragonfly", target_os = "freebsd", target_os = "linux"))]
1029 SeekHole = libc::SEEK_HOLE
1030 }
1031
1032 /// Move the read/write file offset.
1033 ///
1034 /// See also [lseek(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/lseek.html)
lseek(fd: RawFd, offset: off_t, whence: Whence) -> Result<off_t>1035 pub fn lseek(fd: RawFd, offset: off_t, whence: Whence) -> Result<off_t> {
1036 let res = unsafe { libc::lseek(fd, offset, whence as i32) };
1037
1038 Errno::result(res).map(|r| r as off_t)
1039 }
1040
1041 #[cfg(any(target_os = "linux", target_os = "android"))]
lseek64(fd: RawFd, offset: libc::off64_t, whence: Whence) -> Result<libc::off64_t>1042 pub fn lseek64(fd: RawFd, offset: libc::off64_t, whence: Whence) -> Result<libc::off64_t> {
1043 let res = unsafe { libc::lseek64(fd, offset, whence as i32) };
1044
1045 Errno::result(res).map(|r| r as libc::off64_t)
1046 }
1047
1048 /// Create an interprocess channel.
1049 ///
1050 /// See also [pipe(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/pipe.html)
pipe() -> Result<(RawFd, RawFd)>1051 pub fn pipe() -> Result<(RawFd, RawFd)> {
1052 unsafe {
1053 let mut fds = mem::MaybeUninit::<[c_int; 2]>::uninit();
1054
1055 let res = libc::pipe(fds.as_mut_ptr() as *mut c_int);
1056
1057 Errno::result(res)?;
1058
1059 Ok((fds.assume_init()[0], fds.assume_init()[1]))
1060 }
1061 }
1062
1063 /// Like `pipe`, but allows setting certain file descriptor flags.
1064 ///
1065 /// The following flags are supported, and will be set atomically as the pipe is
1066 /// created:
1067 ///
1068 /// `O_CLOEXEC`: Set the close-on-exec flag for the new file descriptors.
1069 #[cfg_attr(target_os = "linux", doc = "`O_DIRECT`: Create a pipe that performs I/O in \"packet\" mode. ")]
1070 #[cfg_attr(target_os = "netbsd", doc = "`O_NOSIGPIPE`: Return `EPIPE` instead of raising `SIGPIPE`. ")]
1071 /// `O_NONBLOCK`: Set the non-blocking flag for the ends of the pipe.
1072 ///
1073 /// See also [pipe(2)](http://man7.org/linux/man-pages/man2/pipe.2.html)
1074 #[cfg(any(target_os = "android",
1075 target_os = "dragonfly",
1076 target_os = "emscripten",
1077 target_os = "freebsd",
1078 target_os = "linux",
1079 target_os = "redox",
1080 target_os = "netbsd",
1081 target_os = "openbsd"))]
pipe2(flags: OFlag) -> Result<(RawFd, RawFd)>1082 pub fn pipe2(flags: OFlag) -> Result<(RawFd, RawFd)> {
1083 let mut fds = mem::MaybeUninit::<[c_int; 2]>::uninit();
1084
1085 let res = unsafe {
1086 libc::pipe2(fds.as_mut_ptr() as *mut c_int, flags.bits())
1087 };
1088
1089 Errno::result(res)?;
1090
1091 unsafe { Ok((fds.assume_init()[0], fds.assume_init()[1])) }
1092 }
1093
1094 /// Truncate a file to a specified length
1095 ///
1096 /// See also
1097 /// [truncate(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/truncate.html)
1098 #[cfg(not(target_os = "redox"))]
truncate<P: ?Sized + NixPath>(path: &P, len: off_t) -> Result<()>1099 pub fn truncate<P: ?Sized + NixPath>(path: &P, len: off_t) -> Result<()> {
1100 let res = path.with_nix_path(|cstr| {
1101 unsafe {
1102 libc::truncate(cstr.as_ptr(), len)
1103 }
1104 })?;
1105
1106 Errno::result(res).map(drop)
1107 }
1108
1109 /// Truncate a file to a specified length
1110 ///
1111 /// See also
1112 /// [ftruncate(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html)
ftruncate(fd: RawFd, len: off_t) -> Result<()>1113 pub fn ftruncate(fd: RawFd, len: off_t) -> Result<()> {
1114 Errno::result(unsafe { libc::ftruncate(fd, len) }).map(drop)
1115 }
1116
isatty(fd: RawFd) -> Result<bool>1117 pub fn isatty(fd: RawFd) -> Result<bool> {
1118 unsafe {
1119 // ENOTTY means `fd` is a valid file descriptor, but not a TTY, so
1120 // we return `Ok(false)`
1121 if libc::isatty(fd) == 1 {
1122 Ok(true)
1123 } else {
1124 match Errno::last() {
1125 Errno::ENOTTY => Ok(false),
1126 err => Err(Error::Sys(err)),
1127 }
1128 }
1129 }
1130 }
1131
1132 /// Flags for `linkat` function.
1133 #[derive(Clone, Copy, Debug)]
1134 pub enum LinkatFlags {
1135 SymlinkFollow,
1136 NoSymlinkFollow,
1137 }
1138
1139 /// Link one file to another file
1140 ///
1141 /// Creates a new link (directory entry) at `newpath` for the existing file at `oldpath`. In the
1142 /// case of a relative `oldpath`, the path is interpreted relative to the directory associated
1143 /// with file descriptor `olddirfd` instead of the current working directory and similiarly for
1144 /// `newpath` and file descriptor `newdirfd`. In case `flag` is LinkatFlags::SymlinkFollow and
1145 /// `oldpath` names a symoblic link, a new link for the target of the symbolic link is created.
1146 /// If either `olddirfd` or `newdirfd` is `None`, `AT_FDCWD` is used respectively where `oldpath`
1147 /// and/or `newpath` is then interpreted relative to the current working directory of the calling
1148 /// process. If either `oldpath` or `newpath` is absolute, then `dirfd` is ignored.
1149 ///
1150 /// # References
1151 /// See also [linkat(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/linkat.html)
1152 #[cfg(not(target_os = "redox"))] // RedoxFS does not support symlinks yet
linkat<P: ?Sized + NixPath>( olddirfd: Option<RawFd>, oldpath: &P, newdirfd: Option<RawFd>, newpath: &P, flag: LinkatFlags, ) -> Result<()>1153 pub fn linkat<P: ?Sized + NixPath>(
1154 olddirfd: Option<RawFd>,
1155 oldpath: &P,
1156 newdirfd: Option<RawFd>,
1157 newpath: &P,
1158 flag: LinkatFlags,
1159 ) -> Result<()> {
1160
1161 let atflag =
1162 match flag {
1163 LinkatFlags::SymlinkFollow => AtFlags::AT_SYMLINK_FOLLOW,
1164 LinkatFlags::NoSymlinkFollow => AtFlags::empty(),
1165 };
1166
1167 let res =
1168 oldpath.with_nix_path(|oldcstr| {
1169 newpath.with_nix_path(|newcstr| {
1170 unsafe {
1171 libc::linkat(
1172 at_rawfd(olddirfd),
1173 oldcstr.as_ptr(),
1174 at_rawfd(newdirfd),
1175 newcstr.as_ptr(),
1176 atflag.bits() as libc::c_int
1177 )
1178 }
1179 })
1180 })??;
1181 Errno::result(res).map(drop)
1182 }
1183
1184
1185 /// Remove a directory entry
1186 ///
1187 /// See also [unlink(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/unlink.html)
unlink<P: ?Sized + NixPath>(path: &P) -> Result<()>1188 pub fn unlink<P: ?Sized + NixPath>(path: &P) -> Result<()> {
1189 let res = path.with_nix_path(|cstr| {
1190 unsafe {
1191 libc::unlink(cstr.as_ptr())
1192 }
1193 })?;
1194 Errno::result(res).map(drop)
1195 }
1196
1197 /// Flags for `unlinkat` function.
1198 #[derive(Clone, Copy, Debug)]
1199 pub enum UnlinkatFlags {
1200 RemoveDir,
1201 NoRemoveDir,
1202 }
1203
1204 /// Remove a directory entry
1205 ///
1206 /// In the case of a relative path, the directory entry to be removed is determined relative to
1207 /// the directory associated with the file descriptor `dirfd` or the current working directory
1208 /// if `dirfd` is `None`. In the case of an absolute `path` `dirfd` is ignored. If `flag` is
1209 /// `UnlinkatFlags::RemoveDir` then removal of the directory entry specified by `dirfd` and `path`
1210 /// is performed.
1211 ///
1212 /// # References
1213 /// See also [unlinkat(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/unlinkat.html)
1214 #[cfg(not(target_os = "redox"))]
unlinkat<P: ?Sized + NixPath>( dirfd: Option<RawFd>, path: &P, flag: UnlinkatFlags, ) -> Result<()>1215 pub fn unlinkat<P: ?Sized + NixPath>(
1216 dirfd: Option<RawFd>,
1217 path: &P,
1218 flag: UnlinkatFlags,
1219 ) -> Result<()> {
1220 let atflag =
1221 match flag {
1222 UnlinkatFlags::RemoveDir => AtFlags::AT_REMOVEDIR,
1223 UnlinkatFlags::NoRemoveDir => AtFlags::empty(),
1224 };
1225 let res = path.with_nix_path(|cstr| {
1226 unsafe {
1227 libc::unlinkat(at_rawfd(dirfd), cstr.as_ptr(), atflag.bits() as libc::c_int)
1228 }
1229 })?;
1230 Errno::result(res).map(drop)
1231 }
1232
1233
1234 #[inline]
chroot<P: ?Sized + NixPath>(path: &P) -> Result<()>1235 pub fn chroot<P: ?Sized + NixPath>(path: &P) -> Result<()> {
1236 let res = path.with_nix_path(|cstr| {
1237 unsafe { libc::chroot(cstr.as_ptr()) }
1238 })?;
1239
1240 Errno::result(res).map(drop)
1241 }
1242
1243 /// Commit filesystem caches to disk
1244 ///
1245 /// See also [sync(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/sync.html)
1246 #[cfg(any(
1247 target_os = "dragonfly",
1248 target_os = "freebsd",
1249 target_os = "linux",
1250 target_os = "netbsd",
1251 target_os = "openbsd"
1252 ))]
sync()1253 pub fn sync() {
1254 unsafe { libc::sync() };
1255 }
1256
1257 /// Synchronize changes to a file
1258 ///
1259 /// See also [fsync(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/fsync.html)
1260 #[inline]
fsync(fd: RawFd) -> Result<()>1261 pub fn fsync(fd: RawFd) -> Result<()> {
1262 let res = unsafe { libc::fsync(fd) };
1263
1264 Errno::result(res).map(drop)
1265 }
1266
1267 /// Synchronize the data of a file
1268 ///
1269 /// See also
1270 /// [fdatasync(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/fdatasync.html)
1271 // `fdatasync(2) is in POSIX, but in libc it is only defined in `libc::notbsd`.
1272 // TODO: exclude only Apple systems after https://github.com/rust-lang/libc/pull/211
1273 #[cfg(any(target_os = "linux",
1274 target_os = "android",
1275 target_os = "emscripten"))]
1276 #[inline]
fdatasync(fd: RawFd) -> Result<()>1277 pub fn fdatasync(fd: RawFd) -> Result<()> {
1278 let res = unsafe { libc::fdatasync(fd) };
1279
1280 Errno::result(res).map(drop)
1281 }
1282
1283 /// Get a real user ID
1284 ///
1285 /// See also [getuid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getuid.html)
1286 // POSIX requires that getuid is always successful, so no need to check return
1287 // value or errno.
1288 #[inline]
getuid() -> Uid1289 pub fn getuid() -> Uid {
1290 Uid(unsafe { libc::getuid() })
1291 }
1292
1293 /// Get the effective user ID
1294 ///
1295 /// See also [geteuid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/geteuid.html)
1296 // POSIX requires that geteuid is always successful, so no need to check return
1297 // value or errno.
1298 #[inline]
geteuid() -> Uid1299 pub fn geteuid() -> Uid {
1300 Uid(unsafe { libc::geteuid() })
1301 }
1302
1303 /// Get the real group ID
1304 ///
1305 /// See also [getgid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getgid.html)
1306 // POSIX requires that getgid is always successful, so no need to check return
1307 // value or errno.
1308 #[inline]
getgid() -> Gid1309 pub fn getgid() -> Gid {
1310 Gid(unsafe { libc::getgid() })
1311 }
1312
1313 /// Get the effective group ID
1314 ///
1315 /// See also [getegid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getegid.html)
1316 // POSIX requires that getegid is always successful, so no need to check return
1317 // value or errno.
1318 #[inline]
getegid() -> Gid1319 pub fn getegid() -> Gid {
1320 Gid(unsafe { libc::getegid() })
1321 }
1322
1323 /// Set the effective user ID
1324 ///
1325 /// See also [seteuid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/seteuid.html)
1326 #[inline]
seteuid(euid: Uid) -> Result<()>1327 pub fn seteuid(euid: Uid) -> Result<()> {
1328 let res = unsafe { libc::seteuid(euid.into()) };
1329
1330 Errno::result(res).map(drop)
1331 }
1332
1333 /// Set the effective group ID
1334 ///
1335 /// See also [setegid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/setegid.html)
1336 #[inline]
setegid(egid: Gid) -> Result<()>1337 pub fn setegid(egid: Gid) -> Result<()> {
1338 let res = unsafe { libc::setegid(egid.into()) };
1339
1340 Errno::result(res).map(drop)
1341 }
1342
1343 /// Set the user ID
1344 ///
1345 /// See also [setuid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/setuid.html)
1346 #[inline]
setuid(uid: Uid) -> Result<()>1347 pub fn setuid(uid: Uid) -> Result<()> {
1348 let res = unsafe { libc::setuid(uid.into()) };
1349
1350 Errno::result(res).map(drop)
1351 }
1352
1353 /// Set the group ID
1354 ///
1355 /// See also [setgid(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/setgid.html)
1356 #[inline]
setgid(gid: Gid) -> Result<()>1357 pub fn setgid(gid: Gid) -> Result<()> {
1358 let res = unsafe { libc::setgid(gid.into()) };
1359
1360 Errno::result(res).map(drop)
1361 }
1362
1363 /// Set the user identity used for filesystem checks per-thread.
1364 /// On both success and failure, this call returns the previous filesystem user
1365 /// ID of the caller.
1366 ///
1367 /// See also [setfsuid(2)](http://man7.org/linux/man-pages/man2/setfsuid.2.html)
1368 #[cfg(any(target_os = "linux", target_os = "android"))]
setfsuid(uid: Uid) -> Uid1369 pub fn setfsuid(uid: Uid) -> Uid {
1370 let prev_fsuid = unsafe { libc::setfsuid(uid.into()) };
1371 Uid::from_raw(prev_fsuid as uid_t)
1372 }
1373
1374 /// Set the group identity used for filesystem checks per-thread.
1375 /// On both success and failure, this call returns the previous filesystem group
1376 /// ID of the caller.
1377 ///
1378 /// See also [setfsgid(2)](http://man7.org/linux/man-pages/man2/setfsgid.2.html)
1379 #[cfg(any(target_os = "linux", target_os = "android"))]
setfsgid(gid: Gid) -> Gid1380 pub fn setfsgid(gid: Gid) -> Gid {
1381 let prev_fsgid = unsafe { libc::setfsgid(gid.into()) };
1382 Gid::from_raw(prev_fsgid as gid_t)
1383 }
1384
1385 /// Get the list of supplementary group IDs of the calling process.
1386 ///
1387 /// [Further reading](http://pubs.opengroup.org/onlinepubs/009695399/functions/getgroups.html)
1388 ///
1389 /// **Note:** This function is not available for Apple platforms. On those
1390 /// platforms, checking group membership should be achieved via communication
1391 /// with the `opendirectoryd` service.
1392 #[cfg(not(any(target_os = "ios", target_os = "macos")))]
getgroups() -> Result<Vec<Gid>>1393 pub fn getgroups() -> Result<Vec<Gid>> {
1394 // First get the maximum number of groups. The value returned
1395 // shall always be greater than or equal to one and less than or
1396 // equal to the value of {NGROUPS_MAX} + 1.
1397 let ngroups_max = match sysconf(SysconfVar::NGROUPS_MAX) {
1398 Ok(Some(n)) => (n + 1) as usize,
1399 Ok(None) | Err(_) => <usize>::max_value(),
1400 };
1401
1402 // Next, get the number of groups so we can size our Vec
1403 let ngroups = unsafe { libc::getgroups(0, ptr::null_mut()) };
1404
1405 // Now actually get the groups. We try multiple times in case the number of
1406 // groups has changed since the first call to getgroups() and the buffer is
1407 // now too small.
1408 let mut groups = Vec::<Gid>::with_capacity(Errno::result(ngroups)? as usize);
1409 loop {
1410 // FIXME: On the platforms we currently support, the `Gid` struct has
1411 // the same representation in memory as a bare `gid_t`. This is not
1412 // necessarily the case on all Rust platforms, though. See RFC 1785.
1413 let ngroups = unsafe {
1414 libc::getgroups(groups.capacity() as c_int, groups.as_mut_ptr() as *mut gid_t)
1415 };
1416
1417 match Errno::result(ngroups) {
1418 Ok(s) => {
1419 unsafe { groups.set_len(s as usize) };
1420 return Ok(groups);
1421 },
1422 Err(Error::Sys(Errno::EINVAL)) => {
1423 // EINVAL indicates that the buffer size was too
1424 // small, resize it up to ngroups_max as limit.
1425 reserve_double_buffer_size(&mut groups, ngroups_max)
1426 .or(Err(Error::Sys(Errno::EINVAL)))?;
1427 },
1428 Err(e) => return Err(e)
1429 }
1430 }
1431 }
1432
1433 /// Set the list of supplementary group IDs for the calling process.
1434 ///
1435 /// [Further reading](http://man7.org/linux/man-pages/man2/getgroups.2.html)
1436 ///
1437 /// **Note:** This function is not available for Apple platforms. On those
1438 /// platforms, group membership management should be achieved via communication
1439 /// with the `opendirectoryd` service.
1440 ///
1441 /// # Examples
1442 ///
1443 /// `setgroups` can be used when dropping privileges from the root user to a
1444 /// specific user and group. For example, given the user `www-data` with UID
1445 /// `33` and the group `backup` with the GID `34`, one could switch the user as
1446 /// follows:
1447 ///
1448 /// ```rust,no_run
1449 /// # use std::error::Error;
1450 /// # use nix::unistd::*;
1451 /// #
1452 /// # fn try_main() -> Result<(), Box<Error>> {
1453 /// let uid = Uid::from_raw(33);
1454 /// let gid = Gid::from_raw(34);
1455 /// setgroups(&[gid])?;
1456 /// setgid(gid)?;
1457 /// setuid(uid)?;
1458 /// #
1459 /// # Ok(())
1460 /// # }
1461 /// #
1462 /// # try_main().unwrap();
1463 /// ```
1464 #[cfg(not(any(target_os = "ios", target_os = "macos", target_os = "redox")))]
setgroups(groups: &[Gid]) -> Result<()>1465 pub fn setgroups(groups: &[Gid]) -> Result<()> {
1466 cfg_if! {
1467 if #[cfg(any(target_os = "dragonfly",
1468 target_os = "freebsd",
1469 target_os = "ios",
1470 target_os = "macos",
1471 target_os = "netbsd",
1472 target_os = "openbsd"))] {
1473 type setgroups_ngroups_t = c_int;
1474 } else {
1475 type setgroups_ngroups_t = size_t;
1476 }
1477 }
1478 // FIXME: On the platforms we currently support, the `Gid` struct has the
1479 // same representation in memory as a bare `gid_t`. This is not necessarily
1480 // the case on all Rust platforms, though. See RFC 1785.
1481 let res = unsafe {
1482 libc::setgroups(groups.len() as setgroups_ngroups_t, groups.as_ptr() as *const gid_t)
1483 };
1484
1485 Errno::result(res).map(drop)
1486 }
1487
1488 /// Calculate the supplementary group access list.
1489 ///
1490 /// Gets the group IDs of all groups that `user` is a member of. The additional
1491 /// group `group` is also added to the list.
1492 ///
1493 /// [Further reading](http://man7.org/linux/man-pages/man3/getgrouplist.3.html)
1494 ///
1495 /// **Note:** This function is not available for Apple platforms. On those
1496 /// platforms, checking group membership should be achieved via communication
1497 /// with the `opendirectoryd` service.
1498 ///
1499 /// # Errors
1500 ///
1501 /// Although the `getgrouplist()` call does not return any specific
1502 /// errors on any known platforms, this implementation will return a system
1503 /// error of `EINVAL` if the number of groups to be fetched exceeds the
1504 /// `NGROUPS_MAX` sysconf value. This mimics the behaviour of `getgroups()`
1505 /// and `setgroups()`. Additionally, while some implementations will return a
1506 /// partial list of groups when `NGROUPS_MAX` is exceeded, this implementation
1507 /// will only ever return the complete list or else an error.
1508 #[cfg(not(any(target_os = "ios", target_os = "macos", target_os = "redox")))]
getgrouplist(user: &CStr, group: Gid) -> Result<Vec<Gid>>1509 pub fn getgrouplist(user: &CStr, group: Gid) -> Result<Vec<Gid>> {
1510 let ngroups_max = match sysconf(SysconfVar::NGROUPS_MAX) {
1511 Ok(Some(n)) => n as c_int,
1512 Ok(None) | Err(_) => <c_int>::max_value(),
1513 };
1514 use std::cmp::min;
1515 let mut ngroups = min(ngroups_max, 8);
1516 let mut groups = Vec::<Gid>::with_capacity(ngroups as usize);
1517 cfg_if! {
1518 if #[cfg(any(target_os = "ios", target_os = "macos"))] {
1519 type getgrouplist_group_t = c_int;
1520 } else {
1521 type getgrouplist_group_t = gid_t;
1522 }
1523 }
1524 let gid: gid_t = group.into();
1525 loop {
1526 let ret = unsafe {
1527 libc::getgrouplist(user.as_ptr(),
1528 gid as getgrouplist_group_t,
1529 groups.as_mut_ptr() as *mut getgrouplist_group_t,
1530 &mut ngroups)
1531 };
1532
1533 // BSD systems only return 0 or -1, Linux returns ngroups on success.
1534 if ret >= 0 {
1535 unsafe { groups.set_len(ngroups as usize) };
1536 return Ok(groups);
1537 } else if ret == -1 {
1538 // Returns -1 if ngroups is too small, but does not set errno.
1539 // BSD systems will still fill the groups buffer with as many
1540 // groups as possible, but Linux manpages do not mention this
1541 // behavior.
1542 reserve_double_buffer_size(&mut groups, ngroups_max as usize)
1543 .or_else(|_| Err(Error::invalid_argument()))?;
1544 }
1545 }
1546 }
1547
1548 /// Initialize the supplementary group access list.
1549 ///
1550 /// Sets the supplementary group IDs for the calling process using all groups
1551 /// that `user` is a member of. The additional group `group` is also added to
1552 /// the list.
1553 ///
1554 /// [Further reading](http://man7.org/linux/man-pages/man3/initgroups.3.html)
1555 ///
1556 /// **Note:** This function is not available for Apple platforms. On those
1557 /// platforms, group membership management should be achieved via communication
1558 /// with the `opendirectoryd` service.
1559 ///
1560 /// # Examples
1561 ///
1562 /// `initgroups` can be used when dropping privileges from the root user to
1563 /// another user. For example, given the user `www-data`, we could look up the
1564 /// UID and GID for the user in the system's password database (usually found
1565 /// in `/etc/passwd`). If the `www-data` user's UID and GID were `33` and `33`,
1566 /// respectively, one could switch the user as follows:
1567 ///
1568 /// ```rust,no_run
1569 /// # use std::error::Error;
1570 /// # use std::ffi::CString;
1571 /// # use nix::unistd::*;
1572 /// #
1573 /// # fn try_main() -> Result<(), Box<Error>> {
1574 /// let user = CString::new("www-data").unwrap();
1575 /// let uid = Uid::from_raw(33);
1576 /// let gid = Gid::from_raw(33);
1577 /// initgroups(&user, gid)?;
1578 /// setgid(gid)?;
1579 /// setuid(uid)?;
1580 /// #
1581 /// # Ok(())
1582 /// # }
1583 /// #
1584 /// # try_main().unwrap();
1585 /// ```
1586 #[cfg(not(any(target_os = "ios", target_os = "macos", target_os = "redox")))]
initgroups(user: &CStr, group: Gid) -> Result<()>1587 pub fn initgroups(user: &CStr, group: Gid) -> Result<()> {
1588 cfg_if! {
1589 if #[cfg(any(target_os = "ios", target_os = "macos"))] {
1590 type initgroups_group_t = c_int;
1591 } else {
1592 type initgroups_group_t = gid_t;
1593 }
1594 }
1595 let gid: gid_t = group.into();
1596 let res = unsafe { libc::initgroups(user.as_ptr(), gid as initgroups_group_t) };
1597
1598 Errno::result(res).map(drop)
1599 }
1600
1601 /// Suspend the thread until a signal is received.
1602 ///
1603 /// See also [pause(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/pause.html).
1604 #[inline]
1605 #[cfg(not(target_os = "redox"))]
pause()1606 pub fn pause() {
1607 unsafe { libc::pause() };
1608 }
1609
1610 pub mod alarm {
1611 //! Alarm signal scheduling.
1612 //!
1613 //! Scheduling an alarm will trigger a `SIGALRM` signal when the time has
1614 //! elapsed, which has to be caught, because the default action for the
1615 //! signal is to terminate the program. This signal also can't be ignored
1616 //! because the system calls like `pause` will not be interrupted, see the
1617 //! second example below.
1618 //!
1619 //! # Examples
1620 //!
1621 //! Canceling an alarm:
1622 //!
1623 //! ```
1624 //! use nix::unistd::alarm;
1625 //!
1626 //! // Set an alarm for 60 seconds from now.
1627 //! alarm::set(60);
1628 //!
1629 //! // Cancel the above set alarm, which returns the number of seconds left
1630 //! // of the previously set alarm.
1631 //! assert_eq!(alarm::cancel(), Some(60));
1632 //! ```
1633 //!
1634 //! Scheduling an alarm and waiting for the signal:
1635 //!
1636 //! ```
1637 //! use std::time::{Duration, Instant};
1638 //!
1639 //! use nix::unistd::{alarm, pause};
1640 //! use nix::sys::signal::*;
1641 //!
1642 //! // We need to setup an empty signal handler to catch the alarm signal,
1643 //! // otherwise the program will be terminated once the signal is delivered.
1644 //! extern fn signal_handler(_: nix::libc::c_int) { }
1645 //! unsafe { sigaction(Signal::SIGALRM, &SigAction::new(SigHandler::Handler(signal_handler), SaFlags::empty(), SigSet::empty())); }
1646 //!
1647 //! // Set an alarm for 1 second from now.
1648 //! alarm::set(1);
1649 //!
1650 //! let start = Instant::now();
1651 //! // Pause the process until the alarm signal is received.
1652 //! pause();
1653 //!
1654 //! assert!(start.elapsed() >= Duration::from_secs(1));
1655 //! ```
1656 //!
1657 //! # References
1658 //!
1659 //! See also [alarm(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/alarm.html).
1660
1661 /// Schedule an alarm signal.
1662 ///
1663 /// This will cause the system to generate a `SIGALRM` signal for the
1664 /// process after the specified number of seconds have elapsed.
1665 ///
1666 /// Returns the leftover time of a previously set alarm if there was one.
set(secs: libc::c_uint) -> Option<libc::c_uint>1667 pub fn set(secs: libc::c_uint) -> Option<libc::c_uint> {
1668 assert!(secs != 0, "passing 0 to `alarm::set` is not allowed, to cancel an alarm use `alarm::cancel`");
1669 alarm(secs)
1670 }
1671
1672 /// Cancel an previously set alarm signal.
1673 ///
1674 /// Returns the leftover time of a previously set alarm if there was one.
cancel() -> Option<libc::c_uint>1675 pub fn cancel() -> Option<libc::c_uint> {
1676 alarm(0)
1677 }
1678
alarm(secs: libc::c_uint) -> Option<libc::c_uint>1679 fn alarm(secs: libc::c_uint) -> Option<libc::c_uint> {
1680 match unsafe { libc::alarm(secs) } {
1681 0 => None,
1682 secs => Some(secs),
1683 }
1684 }
1685 }
1686
1687 /// Suspend execution for an interval of time
1688 ///
1689 /// See also [sleep(2)](http://pubs.opengroup.org/onlinepubs/009695399/functions/sleep.html#tag_03_705_05)
1690 // Per POSIX, does not fail
1691 #[inline]
sleep(seconds: c_uint) -> c_uint1692 pub fn sleep(seconds: c_uint) -> c_uint {
1693 unsafe { libc::sleep(seconds) }
1694 }
1695
1696 #[cfg(not(target_os = "redox"))]
1697 pub mod acct {
1698 use crate::{Result, NixPath};
1699 use crate::errno::Errno;
1700 use std::ptr;
1701
1702 /// Enable process accounting
1703 ///
1704 /// See also [acct(2)](https://linux.die.net/man/2/acct)
enable<P: ?Sized + NixPath>(filename: &P) -> Result<()>1705 pub fn enable<P: ?Sized + NixPath>(filename: &P) -> Result<()> {
1706 let res = filename.with_nix_path(|cstr| {
1707 unsafe { libc::acct(cstr.as_ptr()) }
1708 })?;
1709
1710 Errno::result(res).map(drop)
1711 }
1712
1713 /// Disable process accounting
disable() -> Result<()>1714 pub fn disable() -> Result<()> {
1715 let res = unsafe { libc::acct(ptr::null()) };
1716
1717 Errno::result(res).map(drop)
1718 }
1719 }
1720
1721 /// Creates a regular file which persists even after process termination
1722 ///
1723 /// * `template`: a path whose 6 rightmost characters must be X, e.g. `/tmp/tmpfile_XXXXXX`
1724 /// * returns: tuple of file descriptor and filename
1725 ///
1726 /// Err is returned either if no temporary filename could be created or the template doesn't
1727 /// end with XXXXXX
1728 ///
1729 /// See also [mkstemp(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/mkstemp.html)
1730 ///
1731 /// # Example
1732 ///
1733 /// ```rust
1734 /// use nix::unistd;
1735 ///
1736 /// let _ = match unistd::mkstemp("/tmp/tempfile_XXXXXX") {
1737 /// Ok((fd, path)) => {
1738 /// unistd::unlink(path.as_path()).unwrap(); // flag file to be deleted at app termination
1739 /// fd
1740 /// }
1741 /// Err(e) => panic!("mkstemp failed: {}", e)
1742 /// };
1743 /// // do something with fd
1744 /// ```
1745 #[inline]
mkstemp<P: ?Sized + NixPath>(template: &P) -> Result<(RawFd, PathBuf)>1746 pub fn mkstemp<P: ?Sized + NixPath>(template: &P) -> Result<(RawFd, PathBuf)> {
1747 let mut path = template.with_nix_path(|path| {path.to_bytes_with_nul().to_owned()})?;
1748 let p = path.as_mut_ptr() as *mut _;
1749 let fd = unsafe { libc::mkstemp(p) };
1750 let last = path.pop(); // drop the trailing nul
1751 debug_assert!(last == Some(b'\0'));
1752 let pathname = OsString::from_vec(path);
1753 Errno::result(fd)?;
1754 Ok((fd, PathBuf::from(pathname)))
1755 }
1756
1757 /// Variable names for `pathconf`
1758 ///
1759 /// Nix uses the same naming convention for these variables as the
1760 /// [getconf(1)](http://pubs.opengroup.org/onlinepubs/9699919799/utilities/getconf.html) utility.
1761 /// That is, `PathconfVar` variables have the same name as the abstract
1762 /// variables shown in the `pathconf(2)` man page. Usually, it's the same as
1763 /// the C variable name without the leading `_PC_`.
1764 ///
1765 /// POSIX 1003.1-2008 standardizes all of these variables, but some OSes choose
1766 /// not to implement variables that cannot change at runtime.
1767 ///
1768 /// # References
1769 ///
1770 /// - [pathconf(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/pathconf.html)
1771 /// - [limits.h](http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html)
1772 /// - [unistd.h](http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/unistd.h.html)
1773 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
1774 #[repr(i32)]
1775 pub enum PathconfVar {
1776 #[cfg(any(target_os = "dragonfly", target_os = "freebsd", target_os = "linux",
1777 target_os = "netbsd", target_os = "openbsd", target_os = "redox"))]
1778 /// Minimum number of bits needed to represent, as a signed integer value,
1779 /// the maximum size of a regular file allowed in the specified directory.
1780 FILESIZEBITS = libc::_PC_FILESIZEBITS,
1781 /// Maximum number of links to a single file.
1782 LINK_MAX = libc::_PC_LINK_MAX,
1783 /// Maximum number of bytes in a terminal canonical input line.
1784 MAX_CANON = libc::_PC_MAX_CANON,
1785 /// Minimum number of bytes for which space is available in a terminal input
1786 /// queue; therefore, the maximum number of bytes a conforming application
1787 /// may require to be typed as input before reading them.
1788 MAX_INPUT = libc::_PC_MAX_INPUT,
1789 /// Maximum number of bytes in a filename (not including the terminating
1790 /// null of a filename string).
1791 NAME_MAX = libc::_PC_NAME_MAX,
1792 /// Maximum number of bytes the implementation will store as a pathname in a
1793 /// user-supplied buffer of unspecified size, including the terminating null
1794 /// character. Minimum number the implementation will accept as the maximum
1795 /// number of bytes in a pathname.
1796 PATH_MAX = libc::_PC_PATH_MAX,
1797 /// Maximum number of bytes that is guaranteed to be atomic when writing to
1798 /// a pipe.
1799 PIPE_BUF = libc::_PC_PIPE_BUF,
1800 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "linux",
1801 target_os = "netbsd", target_os = "openbsd", target_os = "redox"))]
1802 /// Symbolic links can be created.
1803 POSIX2_SYMLINKS = libc::_PC_2_SYMLINKS,
1804 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
1805 target_os = "linux", target_os = "openbsd", target_os = "redox"))]
1806 /// Minimum number of bytes of storage actually allocated for any portion of
1807 /// a file.
1808 POSIX_ALLOC_SIZE_MIN = libc::_PC_ALLOC_SIZE_MIN,
1809 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
1810 target_os = "linux", target_os = "openbsd"))]
1811 /// Recommended increment for file transfer sizes between the
1812 /// `POSIX_REC_MIN_XFER_SIZE` and `POSIX_REC_MAX_XFER_SIZE` values.
1813 POSIX_REC_INCR_XFER_SIZE = libc::_PC_REC_INCR_XFER_SIZE,
1814 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
1815 target_os = "linux", target_os = "openbsd", target_os = "redox"))]
1816 /// Maximum recommended file transfer size.
1817 POSIX_REC_MAX_XFER_SIZE = libc::_PC_REC_MAX_XFER_SIZE,
1818 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
1819 target_os = "linux", target_os = "openbsd", target_os = "redox"))]
1820 /// Minimum recommended file transfer size.
1821 POSIX_REC_MIN_XFER_SIZE = libc::_PC_REC_MIN_XFER_SIZE,
1822 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
1823 target_os = "linux", target_os = "openbsd", target_os = "redox"))]
1824 /// Recommended file transfer buffer alignment.
1825 POSIX_REC_XFER_ALIGN = libc::_PC_REC_XFER_ALIGN,
1826 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
1827 target_os = "linux", target_os = "netbsd", target_os = "openbsd",
1828 target_os = "redox"))]
1829 /// Maximum number of bytes in a symbolic link.
1830 SYMLINK_MAX = libc::_PC_SYMLINK_MAX,
1831 /// The use of `chown` and `fchown` is restricted to a process with
1832 /// appropriate privileges, and to changing the group ID of a file only to
1833 /// the effective group ID of the process or to one of its supplementary
1834 /// group IDs.
1835 _POSIX_CHOWN_RESTRICTED = libc::_PC_CHOWN_RESTRICTED,
1836 /// Pathname components longer than {NAME_MAX} generate an error.
1837 _POSIX_NO_TRUNC = libc::_PC_NO_TRUNC,
1838 /// This symbol shall be defined to be the value of a character that shall
1839 /// disable terminal special character handling.
1840 _POSIX_VDISABLE = libc::_PC_VDISABLE,
1841 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
1842 target_os = "linux", target_os = "openbsd", target_os = "redox"))]
1843 /// Asynchronous input or output operations may be performed for the
1844 /// associated file.
1845 _POSIX_ASYNC_IO = libc::_PC_ASYNC_IO,
1846 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
1847 target_os = "linux", target_os = "openbsd", target_os = "redox"))]
1848 /// Prioritized input or output operations may be performed for the
1849 /// associated file.
1850 _POSIX_PRIO_IO = libc::_PC_PRIO_IO,
1851 #[cfg(any(target_os = "android", target_os = "dragonfly", target_os = "freebsd",
1852 target_os = "linux", target_os = "netbsd", target_os = "openbsd",
1853 target_os = "redox"))]
1854 /// Synchronized input or output operations may be performed for the
1855 /// associated file.
1856 _POSIX_SYNC_IO = libc::_PC_SYNC_IO,
1857 #[cfg(any(target_os = "dragonfly", target_os = "openbsd"))]
1858 /// The resolution in nanoseconds for all file timestamps.
1859 _POSIX_TIMESTAMP_RESOLUTION = libc::_PC_TIMESTAMP_RESOLUTION
1860 }
1861
1862 /// Like `pathconf`, but works with file descriptors instead of paths (see
1863 /// [fpathconf(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/pathconf.html))
1864 ///
1865 /// # Parameters
1866 ///
1867 /// - `fd`: The file descriptor whose variable should be interrogated
1868 /// - `var`: The pathconf variable to lookup
1869 ///
1870 /// # Returns
1871 ///
1872 /// - `Ok(Some(x))`: the variable's limit (for limit variables) or its
1873 /// implementation level (for option variables). Implementation levels are
1874 /// usually a decimal-coded date, such as 200112 for POSIX 2001.12
1875 /// - `Ok(None)`: the variable has no limit (for limit variables) or is
1876 /// unsupported (for option variables)
1877 /// - `Err(x)`: an error occurred
fpathconf(fd: RawFd, var: PathconfVar) -> Result<Option<c_long>>1878 pub fn fpathconf(fd: RawFd, var: PathconfVar) -> Result<Option<c_long>> {
1879 let raw = unsafe {
1880 Errno::clear();
1881 libc::fpathconf(fd, var as c_int)
1882 };
1883 if raw == -1 {
1884 if errno::errno() == 0 {
1885 Ok(None)
1886 } else {
1887 Err(Error::Sys(Errno::last()))
1888 }
1889 } else {
1890 Ok(Some(raw))
1891 }
1892 }
1893
1894 /// Get path-dependent configurable system variables (see
1895 /// [pathconf(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/pathconf.html))
1896 ///
1897 /// Returns the value of a path-dependent configurable system variable. Most
1898 /// supported variables also have associated compile-time constants, but POSIX
1899 /// allows their values to change at runtime. There are generally two types of
1900 /// `pathconf` variables: options and limits. See [pathconf(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/pathconf.html) for more details.
1901 ///
1902 /// # Parameters
1903 ///
1904 /// - `path`: Lookup the value of `var` for this file or directory
1905 /// - `var`: The `pathconf` variable to lookup
1906 ///
1907 /// # Returns
1908 ///
1909 /// - `Ok(Some(x))`: the variable's limit (for limit variables) or its
1910 /// implementation level (for option variables). Implementation levels are
1911 /// usually a decimal-coded date, such as 200112 for POSIX 2001.12
1912 /// - `Ok(None)`: the variable has no limit (for limit variables) or is
1913 /// unsupported (for option variables)
1914 /// - `Err(x)`: an error occurred
pathconf<P: ?Sized + NixPath>(path: &P, var: PathconfVar) -> Result<Option<c_long>>1915 pub fn pathconf<P: ?Sized + NixPath>(path: &P, var: PathconfVar) -> Result<Option<c_long>> {
1916 let raw = path.with_nix_path(|cstr| {
1917 unsafe {
1918 Errno::clear();
1919 libc::pathconf(cstr.as_ptr(), var as c_int)
1920 }
1921 })?;
1922 if raw == -1 {
1923 if errno::errno() == 0 {
1924 Ok(None)
1925 } else {
1926 Err(Error::Sys(Errno::last()))
1927 }
1928 } else {
1929 Ok(Some(raw))
1930 }
1931 }
1932
1933 /// Variable names for `sysconf`
1934 ///
1935 /// Nix uses the same naming convention for these variables as the
1936 /// [getconf(1)](http://pubs.opengroup.org/onlinepubs/9699919799/utilities/getconf.html) utility.
1937 /// That is, `SysconfVar` variables have the same name as the abstract variables
1938 /// shown in the `sysconf(3)` man page. Usually, it's the same as the C
1939 /// variable name without the leading `_SC_`.
1940 ///
1941 /// All of these symbols are standardized by POSIX 1003.1-2008, but haven't been
1942 /// implemented by all platforms.
1943 ///
1944 /// # References
1945 ///
1946 /// - [sysconf(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/sysconf.html)
1947 /// - [unistd.h](http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/unistd.h.html)
1948 /// - [limits.h](http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html)
1949 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
1950 #[repr(i32)]
1951 pub enum SysconfVar {
1952 /// Maximum number of I/O operations in a single list I/O call supported by
1953 /// the implementation.
1954 #[cfg(not(target_os = "redox"))]
1955 AIO_LISTIO_MAX = libc::_SC_AIO_LISTIO_MAX,
1956 /// Maximum number of outstanding asynchronous I/O operations supported by
1957 /// the implementation.
1958 #[cfg(not(target_os = "redox"))]
1959 AIO_MAX = libc::_SC_AIO_MAX,
1960 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
1961 target_os = "ios", target_os="linux", target_os = "macos",
1962 target_os="openbsd"))]
1963 /// The maximum amount by which a process can decrease its asynchronous I/O
1964 /// priority level from its own scheduling priority.
1965 AIO_PRIO_DELTA_MAX = libc::_SC_AIO_PRIO_DELTA_MAX,
1966 /// Maximum length of argument to the exec functions including environment data.
1967 ARG_MAX = libc::_SC_ARG_MAX,
1968 /// Maximum number of functions that may be registered with `atexit`.
1969 #[cfg(not(target_os = "redox"))]
1970 ATEXIT_MAX = libc::_SC_ATEXIT_MAX,
1971 /// Maximum obase values allowed by the bc utility.
1972 #[cfg(not(target_os = "redox"))]
1973 BC_BASE_MAX = libc::_SC_BC_BASE_MAX,
1974 /// Maximum number of elements permitted in an array by the bc utility.
1975 #[cfg(not(target_os = "redox"))]
1976 BC_DIM_MAX = libc::_SC_BC_DIM_MAX,
1977 /// Maximum scale value allowed by the bc utility.
1978 #[cfg(not(target_os = "redox"))]
1979 BC_SCALE_MAX = libc::_SC_BC_SCALE_MAX,
1980 /// Maximum length of a string constant accepted by the bc utility.
1981 #[cfg(not(target_os = "redox"))]
1982 BC_STRING_MAX = libc::_SC_BC_STRING_MAX,
1983 /// Maximum number of simultaneous processes per real user ID.
1984 CHILD_MAX = libc::_SC_CHILD_MAX,
1985 // The number of clock ticks per second.
1986 CLK_TCK = libc::_SC_CLK_TCK,
1987 /// Maximum number of weights that can be assigned to an entry of the
1988 /// LC_COLLATE order keyword in the locale definition file
1989 #[cfg(not(target_os = "redox"))]
1990 COLL_WEIGHTS_MAX = libc::_SC_COLL_WEIGHTS_MAX,
1991 /// Maximum number of timer expiration overruns.
1992 #[cfg(not(target_os = "redox"))]
1993 DELAYTIMER_MAX = libc::_SC_DELAYTIMER_MAX,
1994 /// Maximum number of expressions that can be nested within parentheses by
1995 /// the expr utility.
1996 #[cfg(not(target_os = "redox"))]
1997 EXPR_NEST_MAX = libc::_SC_EXPR_NEST_MAX,
1998 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
1999 target_os="linux", target_os = "macos", target_os="netbsd",
2000 target_os="openbsd"))]
2001 /// Maximum length of a host name (not including the terminating null) as
2002 /// returned from the `gethostname` function
2003 HOST_NAME_MAX = libc::_SC_HOST_NAME_MAX,
2004 /// Maximum number of iovec structures that one process has available for
2005 /// use with `readv` or `writev`.
2006 #[cfg(not(target_os = "redox"))]
2007 IOV_MAX = libc::_SC_IOV_MAX,
2008 /// Unless otherwise noted, the maximum length, in bytes, of a utility's
2009 /// input line (either standard input or another file), when the utility is
2010 /// described as processing text files. The length includes room for the
2011 /// trailing <newline>.
2012 #[cfg(not(target_os = "redox"))]
2013 LINE_MAX = libc::_SC_LINE_MAX,
2014 /// Maximum length of a login name.
2015 LOGIN_NAME_MAX = libc::_SC_LOGIN_NAME_MAX,
2016 /// Maximum number of simultaneous supplementary group IDs per process.
2017 NGROUPS_MAX = libc::_SC_NGROUPS_MAX,
2018 /// Initial size of `getgrgid_r` and `getgrnam_r` data buffers
2019 #[cfg(not(target_os = "redox"))]
2020 GETGR_R_SIZE_MAX = libc::_SC_GETGR_R_SIZE_MAX,
2021 /// Initial size of `getpwuid_r` and `getpwnam_r` data buffers
2022 #[cfg(not(target_os = "redox"))]
2023 GETPW_R_SIZE_MAX = libc::_SC_GETPW_R_SIZE_MAX,
2024 /// The maximum number of open message queue descriptors a process may hold.
2025 #[cfg(not(target_os = "redox"))]
2026 MQ_OPEN_MAX = libc::_SC_MQ_OPEN_MAX,
2027 /// The maximum number of message priorities supported by the implementation.
2028 #[cfg(not(target_os = "redox"))]
2029 MQ_PRIO_MAX = libc::_SC_MQ_PRIO_MAX,
2030 /// A value one greater than the maximum value that the system may assign to
2031 /// a newly-created file descriptor.
2032 OPEN_MAX = libc::_SC_OPEN_MAX,
2033 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2034 target_os="linux", target_os = "macos", target_os="openbsd"))]
2035 /// The implementation supports the Advisory Information option.
2036 _POSIX_ADVISORY_INFO = libc::_SC_ADVISORY_INFO,
2037 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2038 target_os="linux", target_os = "macos", target_os="netbsd",
2039 target_os="openbsd"))]
2040 /// The implementation supports barriers.
2041 _POSIX_BARRIERS = libc::_SC_BARRIERS,
2042 /// The implementation supports asynchronous input and output.
2043 #[cfg(not(target_os = "redox"))]
2044 _POSIX_ASYNCHRONOUS_IO = libc::_SC_ASYNCHRONOUS_IO,
2045 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2046 target_os="linux", target_os = "macos", target_os="netbsd",
2047 target_os="openbsd"))]
2048 /// The implementation supports clock selection.
2049 _POSIX_CLOCK_SELECTION = libc::_SC_CLOCK_SELECTION,
2050 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2051 target_os="linux", target_os = "macos", target_os="netbsd",
2052 target_os="openbsd"))]
2053 /// The implementation supports the Process CPU-Time Clocks option.
2054 _POSIX_CPUTIME = libc::_SC_CPUTIME,
2055 /// The implementation supports the File Synchronization option.
2056 #[cfg(not(target_os = "redox"))]
2057 _POSIX_FSYNC = libc::_SC_FSYNC,
2058 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2059 target_os="linux", target_os = "macos", target_os="openbsd"))]
2060 /// The implementation supports the IPv6 option.
2061 _POSIX_IPV6 = libc::_SC_IPV6,
2062 /// The implementation supports job control.
2063 #[cfg(not(target_os = "redox"))]
2064 _POSIX_JOB_CONTROL = libc::_SC_JOB_CONTROL,
2065 /// The implementation supports memory mapped Files.
2066 #[cfg(not(target_os = "redox"))]
2067 _POSIX_MAPPED_FILES = libc::_SC_MAPPED_FILES,
2068 /// The implementation supports the Process Memory Locking option.
2069 #[cfg(not(target_os = "redox"))]
2070 _POSIX_MEMLOCK = libc::_SC_MEMLOCK,
2071 /// The implementation supports the Range Memory Locking option.
2072 #[cfg(not(target_os = "redox"))]
2073 _POSIX_MEMLOCK_RANGE = libc::_SC_MEMLOCK_RANGE,
2074 /// The implementation supports memory protection.
2075 #[cfg(not(target_os = "redox"))]
2076 _POSIX_MEMORY_PROTECTION = libc::_SC_MEMORY_PROTECTION,
2077 /// The implementation supports the Message Passing option.
2078 #[cfg(not(target_os = "redox"))]
2079 _POSIX_MESSAGE_PASSING = libc::_SC_MESSAGE_PASSING,
2080 /// The implementation supports the Monotonic Clock option.
2081 #[cfg(not(target_os = "redox"))]
2082 _POSIX_MONOTONIC_CLOCK = libc::_SC_MONOTONIC_CLOCK,
2083 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2084 target_os = "ios", target_os="linux", target_os = "macos",
2085 target_os="openbsd"))]
2086 /// The implementation supports the Prioritized Input and Output option.
2087 _POSIX_PRIORITIZED_IO = libc::_SC_PRIORITIZED_IO,
2088 /// The implementation supports the Process Scheduling option.
2089 #[cfg(not(target_os = "redox"))]
2090 _POSIX_PRIORITY_SCHEDULING = libc::_SC_PRIORITY_SCHEDULING,
2091 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2092 target_os="linux", target_os = "macos", target_os="openbsd"))]
2093 /// The implementation supports the Raw Sockets option.
2094 _POSIX_RAW_SOCKETS = libc::_SC_RAW_SOCKETS,
2095 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2096 target_os="linux", target_os = "macos", target_os="netbsd",
2097 target_os="openbsd"))]
2098 /// The implementation supports read-write locks.
2099 _POSIX_READER_WRITER_LOCKS = libc::_SC_READER_WRITER_LOCKS,
2100 #[cfg(any(target_os = "android", target_os="dragonfly", target_os="freebsd",
2101 target_os = "ios", target_os="linux", target_os = "macos",
2102 target_os = "openbsd"))]
2103 /// The implementation supports realtime signals.
2104 _POSIX_REALTIME_SIGNALS = libc::_SC_REALTIME_SIGNALS,
2105 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2106 target_os="linux", target_os = "macos", target_os="netbsd",
2107 target_os="openbsd"))]
2108 /// The implementation supports the Regular Expression Handling option.
2109 _POSIX_REGEXP = libc::_SC_REGEXP,
2110 /// Each process has a saved set-user-ID and a saved set-group-ID.
2111 #[cfg(not(target_os = "redox"))]
2112 _POSIX_SAVED_IDS = libc::_SC_SAVED_IDS,
2113 /// The implementation supports semaphores.
2114 #[cfg(not(target_os = "redox"))]
2115 _POSIX_SEMAPHORES = libc::_SC_SEMAPHORES,
2116 /// The implementation supports the Shared Memory Objects option.
2117 #[cfg(not(target_os = "redox"))]
2118 _POSIX_SHARED_MEMORY_OBJECTS = libc::_SC_SHARED_MEMORY_OBJECTS,
2119 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2120 target_os="linux", target_os = "macos", target_os="netbsd",
2121 target_os="openbsd"))]
2122 /// The implementation supports the POSIX shell.
2123 _POSIX_SHELL = libc::_SC_SHELL,
2124 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2125 target_os="linux", target_os = "macos", target_os="netbsd",
2126 target_os="openbsd"))]
2127 /// The implementation supports the Spawn option.
2128 _POSIX_SPAWN = libc::_SC_SPAWN,
2129 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2130 target_os="linux", target_os = "macos", target_os="netbsd",
2131 target_os="openbsd"))]
2132 /// The implementation supports spin locks.
2133 _POSIX_SPIN_LOCKS = libc::_SC_SPIN_LOCKS,
2134 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2135 target_os="linux", target_os = "macos", target_os="openbsd"))]
2136 /// The implementation supports the Process Sporadic Server option.
2137 _POSIX_SPORADIC_SERVER = libc::_SC_SPORADIC_SERVER,
2138 #[cfg(any(target_os = "ios", target_os="linux", target_os = "macos",
2139 target_os="openbsd"))]
2140 _POSIX_SS_REPL_MAX = libc::_SC_SS_REPL_MAX,
2141 /// The implementation supports the Synchronized Input and Output option.
2142 #[cfg(not(target_os = "redox"))]
2143 _POSIX_SYNCHRONIZED_IO = libc::_SC_SYNCHRONIZED_IO,
2144 /// The implementation supports the Thread Stack Address Attribute option.
2145 #[cfg(not(target_os = "redox"))]
2146 _POSIX_THREAD_ATTR_STACKADDR = libc::_SC_THREAD_ATTR_STACKADDR,
2147 /// The implementation supports the Thread Stack Size Attribute option.
2148 #[cfg(not(target_os = "redox"))]
2149 _POSIX_THREAD_ATTR_STACKSIZE = libc::_SC_THREAD_ATTR_STACKSIZE,
2150 #[cfg(any(target_os = "ios", target_os="linux", target_os = "macos",
2151 target_os="netbsd", target_os="openbsd"))]
2152 /// The implementation supports the Thread CPU-Time Clocks option.
2153 _POSIX_THREAD_CPUTIME = libc::_SC_THREAD_CPUTIME,
2154 /// The implementation supports the Non-Robust Mutex Priority Inheritance
2155 /// option.
2156 #[cfg(not(target_os = "redox"))]
2157 _POSIX_THREAD_PRIO_INHERIT = libc::_SC_THREAD_PRIO_INHERIT,
2158 /// The implementation supports the Non-Robust Mutex Priority Protection option.
2159 #[cfg(not(target_os = "redox"))]
2160 _POSIX_THREAD_PRIO_PROTECT = libc::_SC_THREAD_PRIO_PROTECT,
2161 /// The implementation supports the Thread Execution Scheduling option.
2162 #[cfg(not(target_os = "redox"))]
2163 _POSIX_THREAD_PRIORITY_SCHEDULING = libc::_SC_THREAD_PRIORITY_SCHEDULING,
2164 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2165 target_os="linux", target_os = "macos", target_os="netbsd",
2166 target_os="openbsd"))]
2167 /// The implementation supports the Thread Process-Shared Synchronization
2168 /// option.
2169 _POSIX_THREAD_PROCESS_SHARED = libc::_SC_THREAD_PROCESS_SHARED,
2170 #[cfg(any(target_os="dragonfly", target_os="linux", target_os="openbsd"))]
2171 /// The implementation supports the Robust Mutex Priority Inheritance option.
2172 _POSIX_THREAD_ROBUST_PRIO_INHERIT = libc::_SC_THREAD_ROBUST_PRIO_INHERIT,
2173 #[cfg(any(target_os="dragonfly", target_os="linux", target_os="openbsd"))]
2174 /// The implementation supports the Robust Mutex Priority Protection option.
2175 _POSIX_THREAD_ROBUST_PRIO_PROTECT = libc::_SC_THREAD_ROBUST_PRIO_PROTECT,
2176 /// The implementation supports thread-safe functions.
2177 #[cfg(not(target_os = "redox"))]
2178 _POSIX_THREAD_SAFE_FUNCTIONS = libc::_SC_THREAD_SAFE_FUNCTIONS,
2179 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2180 target_os="linux", target_os = "macos", target_os="openbsd"))]
2181 /// The implementation supports the Thread Sporadic Server option.
2182 _POSIX_THREAD_SPORADIC_SERVER = libc::_SC_THREAD_SPORADIC_SERVER,
2183 /// The implementation supports threads.
2184 #[cfg(not(target_os = "redox"))]
2185 _POSIX_THREADS = libc::_SC_THREADS,
2186 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2187 target_os="linux", target_os = "macos", target_os="openbsd"))]
2188 /// The implementation supports timeouts.
2189 _POSIX_TIMEOUTS = libc::_SC_TIMEOUTS,
2190 /// The implementation supports timers.
2191 #[cfg(not(target_os = "redox"))]
2192 _POSIX_TIMERS = libc::_SC_TIMERS,
2193 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2194 target_os="linux", target_os = "macos", target_os="openbsd"))]
2195 /// The implementation supports the Trace option.
2196 _POSIX_TRACE = libc::_SC_TRACE,
2197 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2198 target_os="linux", target_os = "macos", target_os="openbsd"))]
2199 /// The implementation supports the Trace Event Filter option.
2200 _POSIX_TRACE_EVENT_FILTER = libc::_SC_TRACE_EVENT_FILTER,
2201 #[cfg(any(target_os = "ios", target_os="linux", target_os = "macos",
2202 target_os="openbsd"))]
2203 _POSIX_TRACE_EVENT_NAME_MAX = libc::_SC_TRACE_EVENT_NAME_MAX,
2204 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2205 target_os="linux", target_os = "macos", target_os="openbsd"))]
2206 /// The implementation supports the Trace Inherit option.
2207 _POSIX_TRACE_INHERIT = libc::_SC_TRACE_INHERIT,
2208 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2209 target_os="linux", target_os = "macos", target_os="openbsd"))]
2210 /// The implementation supports the Trace Log option.
2211 _POSIX_TRACE_LOG = libc::_SC_TRACE_LOG,
2212 #[cfg(any(target_os = "ios", target_os="linux", target_os = "macos",
2213 target_os="openbsd"))]
2214 _POSIX_TRACE_NAME_MAX = libc::_SC_TRACE_NAME_MAX,
2215 #[cfg(any(target_os = "ios", target_os="linux", target_os = "macos",
2216 target_os="openbsd"))]
2217 _POSIX_TRACE_SYS_MAX = libc::_SC_TRACE_SYS_MAX,
2218 #[cfg(any(target_os = "ios", target_os="linux", target_os = "macos",
2219 target_os="openbsd"))]
2220 _POSIX_TRACE_USER_EVENT_MAX = libc::_SC_TRACE_USER_EVENT_MAX,
2221 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2222 target_os="linux", target_os = "macos", target_os="openbsd"))]
2223 /// The implementation supports the Typed Memory Objects option.
2224 _POSIX_TYPED_MEMORY_OBJECTS = libc::_SC_TYPED_MEMORY_OBJECTS,
2225 /// Integer value indicating version of this standard (C-language binding)
2226 /// to which the implementation conforms. For implementations conforming to
2227 /// POSIX.1-2008, the value shall be 200809L.
2228 _POSIX_VERSION = libc::_SC_VERSION,
2229 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2230 target_os="linux", target_os = "macos", target_os="netbsd",
2231 target_os="openbsd"))]
2232 /// The implementation provides a C-language compilation environment with
2233 /// 32-bit `int`, `long`, `pointer`, and `off_t` types.
2234 _POSIX_V6_ILP32_OFF32 = libc::_SC_V6_ILP32_OFF32,
2235 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2236 target_os="linux", target_os = "macos", target_os="netbsd",
2237 target_os="openbsd"))]
2238 /// The implementation provides a C-language compilation environment with
2239 /// 32-bit `int`, `long`, and pointer types and an `off_t` type using at
2240 /// least 64 bits.
2241 _POSIX_V6_ILP32_OFFBIG = libc::_SC_V6_ILP32_OFFBIG,
2242 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2243 target_os="linux", target_os = "macos", target_os="netbsd",
2244 target_os="openbsd"))]
2245 /// The implementation provides a C-language compilation environment with
2246 /// 32-bit `int` and 64-bit `long`, `pointer`, and `off_t` types.
2247 _POSIX_V6_LP64_OFF64 = libc::_SC_V6_LP64_OFF64,
2248 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2249 target_os="linux", target_os = "macos", target_os="netbsd",
2250 target_os="openbsd"))]
2251 /// The implementation provides a C-language compilation environment with an
2252 /// `int` type using at least 32 bits and `long`, pointer, and `off_t` types
2253 /// using at least 64 bits.
2254 _POSIX_V6_LPBIG_OFFBIG = libc::_SC_V6_LPBIG_OFFBIG,
2255 /// The implementation supports the C-Language Binding option.
2256 #[cfg(not(target_os = "redox"))]
2257 _POSIX2_C_BIND = libc::_SC_2_C_BIND,
2258 /// The implementation supports the C-Language Development Utilities option.
2259 #[cfg(not(target_os = "redox"))]
2260 _POSIX2_C_DEV = libc::_SC_2_C_DEV,
2261 /// The implementation supports the Terminal Characteristics option.
2262 #[cfg(not(target_os = "redox"))]
2263 _POSIX2_CHAR_TERM = libc::_SC_2_CHAR_TERM,
2264 /// The implementation supports the FORTRAN Development Utilities option.
2265 #[cfg(not(target_os = "redox"))]
2266 _POSIX2_FORT_DEV = libc::_SC_2_FORT_DEV,
2267 /// The implementation supports the FORTRAN Runtime Utilities option.
2268 #[cfg(not(target_os = "redox"))]
2269 _POSIX2_FORT_RUN = libc::_SC_2_FORT_RUN,
2270 /// The implementation supports the creation of locales by the localedef
2271 /// utility.
2272 #[cfg(not(target_os = "redox"))]
2273 _POSIX2_LOCALEDEF = libc::_SC_2_LOCALEDEF,
2274 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2275 target_os="linux", target_os = "macos", target_os="netbsd",
2276 target_os="openbsd"))]
2277 /// The implementation supports the Batch Environment Services and Utilities
2278 /// option.
2279 _POSIX2_PBS = libc::_SC_2_PBS,
2280 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2281 target_os="linux", target_os = "macos", target_os="netbsd",
2282 target_os="openbsd"))]
2283 /// The implementation supports the Batch Accounting option.
2284 _POSIX2_PBS_ACCOUNTING = libc::_SC_2_PBS_ACCOUNTING,
2285 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2286 target_os="linux", target_os = "macos", target_os="netbsd",
2287 target_os="openbsd"))]
2288 /// The implementation supports the Batch Checkpoint/Restart option.
2289 _POSIX2_PBS_CHECKPOINT = libc::_SC_2_PBS_CHECKPOINT,
2290 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2291 target_os="linux", target_os = "macos", target_os="netbsd",
2292 target_os="openbsd"))]
2293 /// The implementation supports the Locate Batch Job Request option.
2294 _POSIX2_PBS_LOCATE = libc::_SC_2_PBS_LOCATE,
2295 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2296 target_os="linux", target_os = "macos", target_os="netbsd",
2297 target_os="openbsd"))]
2298 /// The implementation supports the Batch Job Message Request option.
2299 _POSIX2_PBS_MESSAGE = libc::_SC_2_PBS_MESSAGE,
2300 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2301 target_os="linux", target_os = "macos", target_os="netbsd",
2302 target_os="openbsd"))]
2303 /// The implementation supports the Track Batch Job Request option.
2304 _POSIX2_PBS_TRACK = libc::_SC_2_PBS_TRACK,
2305 /// The implementation supports the Software Development Utilities option.
2306 #[cfg(not(target_os = "redox"))]
2307 _POSIX2_SW_DEV = libc::_SC_2_SW_DEV,
2308 /// The implementation supports the User Portability Utilities option.
2309 #[cfg(not(target_os = "redox"))]
2310 _POSIX2_UPE = libc::_SC_2_UPE,
2311 /// Integer value indicating version of the Shell and Utilities volume of
2312 /// POSIX.1 to which the implementation conforms.
2313 #[cfg(not(target_os = "redox"))]
2314 _POSIX2_VERSION = libc::_SC_2_VERSION,
2315 /// The size of a system page in bytes.
2316 ///
2317 /// POSIX also defines an alias named `PAGESIZE`, but Rust does not allow two
2318 /// enum constants to have the same value, so nix omits `PAGESIZE`.
2319 PAGE_SIZE = libc::_SC_PAGE_SIZE,
2320 #[cfg(not(target_os = "redox"))]
2321 PTHREAD_DESTRUCTOR_ITERATIONS = libc::_SC_THREAD_DESTRUCTOR_ITERATIONS,
2322 #[cfg(not(target_os = "redox"))]
2323 PTHREAD_KEYS_MAX = libc::_SC_THREAD_KEYS_MAX,
2324 #[cfg(not(target_os = "redox"))]
2325 PTHREAD_STACK_MIN = libc::_SC_THREAD_STACK_MIN,
2326 #[cfg(not(target_os = "redox"))]
2327 PTHREAD_THREADS_MAX = libc::_SC_THREAD_THREADS_MAX,
2328 RE_DUP_MAX = libc::_SC_RE_DUP_MAX,
2329 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2330 target_os = "ios", target_os="linux", target_os = "macos",
2331 target_os="openbsd"))]
2332 RTSIG_MAX = libc::_SC_RTSIG_MAX,
2333 #[cfg(not(target_os = "redox"))]
2334 SEM_NSEMS_MAX = libc::_SC_SEM_NSEMS_MAX,
2335 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2336 target_os = "ios", target_os="linux", target_os = "macos",
2337 target_os="openbsd"))]
2338 SEM_VALUE_MAX = libc::_SC_SEM_VALUE_MAX,
2339 #[cfg(any(target_os = "android", target_os="dragonfly", target_os="freebsd",
2340 target_os = "ios", target_os="linux", target_os = "macos",
2341 target_os = "openbsd"))]
2342 SIGQUEUE_MAX = libc::_SC_SIGQUEUE_MAX,
2343 STREAM_MAX = libc::_SC_STREAM_MAX,
2344 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2345 target_os="linux", target_os = "macos", target_os="netbsd",
2346 target_os="openbsd"))]
2347 SYMLOOP_MAX = libc::_SC_SYMLOOP_MAX,
2348 #[cfg(not(target_os = "redox"))]
2349 TIMER_MAX = libc::_SC_TIMER_MAX,
2350 TTY_NAME_MAX = libc::_SC_TTY_NAME_MAX,
2351 TZNAME_MAX = libc::_SC_TZNAME_MAX,
2352 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2353 target_os = "ios", target_os="linux", target_os = "macos",
2354 target_os="openbsd"))]
2355 /// The implementation supports the X/Open Encryption Option Group.
2356 _XOPEN_CRYPT = libc::_SC_XOPEN_CRYPT,
2357 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2358 target_os = "ios", target_os="linux", target_os = "macos",
2359 target_os="openbsd"))]
2360 /// The implementation supports the Issue 4, Version 2 Enhanced
2361 /// Internationalization Option Group.
2362 _XOPEN_ENH_I18N = libc::_SC_XOPEN_ENH_I18N,
2363 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2364 target_os = "ios", target_os="linux", target_os = "macos",
2365 target_os="openbsd"))]
2366 _XOPEN_LEGACY = libc::_SC_XOPEN_LEGACY,
2367 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2368 target_os = "ios", target_os="linux", target_os = "macos",
2369 target_os="openbsd"))]
2370 /// The implementation supports the X/Open Realtime Option Group.
2371 _XOPEN_REALTIME = libc::_SC_XOPEN_REALTIME,
2372 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2373 target_os = "ios", target_os="linux", target_os = "macos",
2374 target_os="openbsd"))]
2375 /// The implementation supports the X/Open Realtime Threads Option Group.
2376 _XOPEN_REALTIME_THREADS = libc::_SC_XOPEN_REALTIME_THREADS,
2377 /// The implementation supports the Issue 4, Version 2 Shared Memory Option
2378 /// Group.
2379 #[cfg(not(target_os = "redox"))]
2380 _XOPEN_SHM = libc::_SC_XOPEN_SHM,
2381 #[cfg(any(target_os="dragonfly", target_os="freebsd", target_os = "ios",
2382 target_os="linux", target_os = "macos", target_os="openbsd"))]
2383 /// The implementation supports the XSI STREAMS Option Group.
2384 _XOPEN_STREAMS = libc::_SC_XOPEN_STREAMS,
2385 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2386 target_os = "ios", target_os="linux", target_os = "macos",
2387 target_os="openbsd"))]
2388 /// The implementation supports the XSI option
2389 _XOPEN_UNIX = libc::_SC_XOPEN_UNIX,
2390 #[cfg(any(target_os="android", target_os="dragonfly", target_os="freebsd",
2391 target_os = "ios", target_os="linux", target_os = "macos",
2392 target_os="openbsd"))]
2393 /// Integer value indicating version of the X/Open Portability Guide to
2394 /// which the implementation conforms.
2395 _XOPEN_VERSION = libc::_SC_XOPEN_VERSION,
2396 }
2397
2398 /// Get configurable system variables (see
2399 /// [sysconf(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/sysconf.html))
2400 ///
2401 /// Returns the value of a configurable system variable. Most supported
2402 /// variables also have associated compile-time constants, but POSIX
2403 /// allows their values to change at runtime. There are generally two types of
2404 /// sysconf variables: options and limits. See sysconf(3) for more details.
2405 ///
2406 /// # Returns
2407 ///
2408 /// - `Ok(Some(x))`: the variable's limit (for limit variables) or its
2409 /// implementation level (for option variables). Implementation levels are
2410 /// usually a decimal-coded date, such as 200112 for POSIX 2001.12
2411 /// - `Ok(None)`: the variable has no limit (for limit variables) or is
2412 /// unsupported (for option variables)
2413 /// - `Err(x)`: an error occurred
sysconf(var: SysconfVar) -> Result<Option<c_long>>2414 pub fn sysconf(var: SysconfVar) -> Result<Option<c_long>> {
2415 let raw = unsafe {
2416 Errno::clear();
2417 libc::sysconf(var as c_int)
2418 };
2419 if raw == -1 {
2420 if errno::errno() == 0 {
2421 Ok(None)
2422 } else {
2423 Err(Error::Sys(Errno::last()))
2424 }
2425 } else {
2426 Ok(Some(raw))
2427 }
2428 }
2429
2430 #[cfg(any(target_os = "android", target_os = "linux"))]
2431 mod pivot_root {
2432 use crate::{Result, NixPath};
2433 use crate::errno::Errno;
2434
pivot_root<P1: ?Sized + NixPath, P2: ?Sized + NixPath>( new_root: &P1, put_old: &P2) -> Result<()>2435 pub fn pivot_root<P1: ?Sized + NixPath, P2: ?Sized + NixPath>(
2436 new_root: &P1, put_old: &P2) -> Result<()> {
2437 let res = new_root.with_nix_path(|new_root| {
2438 put_old.with_nix_path(|put_old| {
2439 unsafe {
2440 libc::syscall(libc::SYS_pivot_root, new_root.as_ptr(), put_old.as_ptr())
2441 }
2442 })
2443 })??;
2444
2445 Errno::result(res).map(drop)
2446 }
2447 }
2448
2449 #[cfg(any(target_os = "android", target_os = "freebsd",
2450 target_os = "linux", target_os = "openbsd"))]
2451 mod setres {
2452 use crate::Result;
2453 use crate::errno::Errno;
2454 use super::{Uid, Gid};
2455
2456 /// Sets the real, effective, and saved uid.
2457 /// ([see setresuid(2)](http://man7.org/linux/man-pages/man2/setresuid.2.html))
2458 ///
2459 /// * `ruid`: real user id
2460 /// * `euid`: effective user id
2461 /// * `suid`: saved user id
2462 /// * returns: Ok or libc error code.
2463 ///
2464 /// Err is returned if the user doesn't have permission to set this UID.
2465 #[inline]
setresuid(ruid: Uid, euid: Uid, suid: Uid) -> Result<()>2466 pub fn setresuid(ruid: Uid, euid: Uid, suid: Uid) -> Result<()> {
2467 let res = unsafe { libc::setresuid(ruid.into(), euid.into(), suid.into()) };
2468
2469 Errno::result(res).map(drop)
2470 }
2471
2472 /// Sets the real, effective, and saved gid.
2473 /// ([see setresuid(2)](http://man7.org/linux/man-pages/man2/setresuid.2.html))
2474 ///
2475 /// * `rgid`: real group id
2476 /// * `egid`: effective group id
2477 /// * `sgid`: saved group id
2478 /// * returns: Ok or libc error code.
2479 ///
2480 /// Err is returned if the user doesn't have permission to set this GID.
2481 #[inline]
setresgid(rgid: Gid, egid: Gid, sgid: Gid) -> Result<()>2482 pub fn setresgid(rgid: Gid, egid: Gid, sgid: Gid) -> Result<()> {
2483 let res = unsafe { libc::setresgid(rgid.into(), egid.into(), sgid.into()) };
2484
2485 Errno::result(res).map(drop)
2486 }
2487 }
2488
2489 libc_bitflags!{
2490 /// Options for access()
2491 pub struct AccessFlags : c_int {
2492 /// Test for existence of file.
2493 F_OK;
2494 /// Test for read permission.
2495 R_OK;
2496 /// Test for write permission.
2497 W_OK;
2498 /// Test for execute (search) permission.
2499 X_OK;
2500 }
2501 }
2502
2503 /// Checks the file named by `path` for accessibility according to the flags given by `amode`
2504 /// See [access(2)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/access.html)
access<P: ?Sized + NixPath>(path: &P, amode: AccessFlags) -> Result<()>2505 pub fn access<P: ?Sized + NixPath>(path: &P, amode: AccessFlags) -> Result<()> {
2506 let res = path.with_nix_path(|cstr| {
2507 unsafe {
2508 libc::access(cstr.as_ptr(), amode.bits)
2509 }
2510 })?;
2511 Errno::result(res).map(drop)
2512 }
2513
2514 /// Representation of a User, based on `libc::passwd`
2515 ///
2516 /// The reason some fields in this struct are `String` and others are `CString` is because some
2517 /// fields are based on the user's locale, which could be non-UTF8, while other fields are
2518 /// guaranteed to conform to [`NAME_REGEX`](https://serverfault.com/a/73101/407341), which only
2519 /// contains ASCII.
2520 #[cfg(not(target_os = "redox"))] // RedoxFS does not support passwd
2521 #[derive(Debug, Clone, PartialEq)]
2522 pub struct User {
2523 /// Username
2524 pub name: String,
2525 /// User password (probably encrypted)
2526 pub passwd: CString,
2527 /// User ID
2528 pub uid: Uid,
2529 /// Group ID
2530 pub gid: Gid,
2531 /// User information
2532 #[cfg(not(target_os = "android"))]
2533 pub gecos: CString,
2534 /// Home directory
2535 pub dir: PathBuf,
2536 /// Path to shell
2537 pub shell: PathBuf,
2538 /// Login class
2539 #[cfg(not(any(target_os = "android", target_os = "linux")))]
2540 pub class: CString,
2541 /// Last password change
2542 #[cfg(not(any(target_os = "android", target_os = "linux")))]
2543 pub change: libc::time_t,
2544 /// Expiration time of account
2545 #[cfg(not(any(target_os = "android", target_os = "linux")))]
2546 pub expire: libc::time_t
2547 }
2548
2549 #[cfg(not(target_os = "redox"))] // RedoxFS does not support passwd
2550 impl From<&libc::passwd> for User {
from(pw: &libc::passwd) -> User2551 fn from(pw: &libc::passwd) -> User {
2552 unsafe {
2553 User {
2554 name: CStr::from_ptr((*pw).pw_name).to_string_lossy().into_owned(),
2555 passwd: CString::new(CStr::from_ptr((*pw).pw_passwd).to_bytes()).unwrap(),
2556 #[cfg(not(target_os = "android"))]
2557 gecos: CString::new(CStr::from_ptr((*pw).pw_gecos).to_bytes()).unwrap(),
2558 dir: PathBuf::from(OsStr::from_bytes(CStr::from_ptr((*pw).pw_dir).to_bytes())),
2559 shell: PathBuf::from(OsStr::from_bytes(CStr::from_ptr((*pw).pw_shell).to_bytes())),
2560 uid: Uid::from_raw((*pw).pw_uid),
2561 gid: Gid::from_raw((*pw).pw_gid),
2562 #[cfg(not(any(target_os = "android", target_os = "linux")))]
2563 class: CString::new(CStr::from_ptr((*pw).pw_class).to_bytes()).unwrap(),
2564 #[cfg(not(any(target_os = "android", target_os = "linux")))]
2565 change: (*pw).pw_change,
2566 #[cfg(not(any(target_os = "android", target_os = "linux")))]
2567 expire: (*pw).pw_expire
2568 }
2569 }
2570 }
2571 }
2572
2573 #[cfg(not(target_os = "redox"))] // RedoxFS does not support passwd
2574 impl User {
from_anything<F>(f: F) -> Result<Option<Self>> where F: Fn(*mut libc::passwd, *mut libc::c_char, libc::size_t, *mut *mut libc::passwd) -> libc::c_int2575 fn from_anything<F>(f: F) -> Result<Option<Self>>
2576 where
2577 F: Fn(*mut libc::passwd,
2578 *mut libc::c_char,
2579 libc::size_t,
2580 *mut *mut libc::passwd) -> libc::c_int
2581 {
2582 let buflimit = 16384;
2583 let bufsize = match sysconf(SysconfVar::GETPW_R_SIZE_MAX) {
2584 Ok(Some(n)) => n as usize,
2585 Ok(None) | Err(_) => buflimit as usize,
2586 };
2587
2588 let mut cbuf = Vec::with_capacity(bufsize);
2589 let mut pwd = mem::MaybeUninit::<libc::passwd>::uninit();
2590 let mut res = ptr::null_mut();
2591
2592 loop {
2593 let error = f(pwd.as_mut_ptr(), cbuf.as_mut_ptr(), cbuf.capacity(), &mut res);
2594 if error == 0 {
2595 if res.is_null() {
2596 return Ok(None);
2597 } else {
2598 let pwd = unsafe { pwd.assume_init() };
2599 return Ok(Some(User::from(&pwd)));
2600 }
2601 } else if Errno::last() == Errno::ERANGE {
2602 // Trigger the internal buffer resizing logic.
2603 reserve_double_buffer_size(&mut cbuf, buflimit)?;
2604 } else {
2605 return Err(Error::Sys(Errno::last()));
2606 }
2607 }
2608 }
2609
2610 /// Get a user by UID.
2611 ///
2612 /// Internally, this function calls
2613 /// [getpwuid_r(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getpwuid_r.html)
2614 ///
2615 /// # Examples
2616 ///
2617 /// ```
2618 /// use nix::unistd::{Uid, User};
2619 /// // Returns an Result<Option<User>>, thus the double unwrap.
2620 /// let res = User::from_uid(Uid::from_raw(0)).unwrap().unwrap();
2621 /// assert!(res.name == "root");
2622 /// ```
from_uid(uid: Uid) -> Result<Option<Self>>2623 pub fn from_uid(uid: Uid) -> Result<Option<Self>> {
2624 User::from_anything(|pwd, cbuf, cap, res| {
2625 unsafe { libc::getpwuid_r(uid.0, pwd, cbuf, cap, res) }
2626 })
2627 }
2628
2629 /// Get a user by name.
2630 ///
2631 /// Internally, this function calls
2632 /// [getpwnam_r(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getpwuid_r.html)
2633 ///
2634 /// # Examples
2635 ///
2636 /// ```
2637 /// use nix::unistd::User;
2638 /// // Returns an Result<Option<User>>, thus the double unwrap.
2639 /// let res = User::from_name("root").unwrap().unwrap();
2640 /// assert!(res.name == "root");
2641 /// ```
from_name(name: &str) -> Result<Option<Self>>2642 pub fn from_name(name: &str) -> Result<Option<Self>> {
2643 let name = CString::new(name).unwrap();
2644 User::from_anything(|pwd, cbuf, cap, res| {
2645 unsafe { libc::getpwnam_r(name.as_ptr(), pwd, cbuf, cap, res) }
2646 })
2647 }
2648 }
2649
2650 /// Representation of a Group, based on `libc::group`
2651 #[cfg(not(target_os = "redox"))] // RedoxFS does not support passwd
2652 #[derive(Debug, Clone, PartialEq)]
2653 pub struct Group {
2654 /// Group name
2655 pub name: String,
2656 /// Group ID
2657 pub gid: Gid,
2658 /// List of Group members
2659 pub mem: Vec<String>
2660 }
2661
2662 #[cfg(not(target_os = "redox"))] // RedoxFS does not support passwd
2663 impl From<&libc::group> for Group {
from(gr: &libc::group) -> Group2664 fn from(gr: &libc::group) -> Group {
2665 unsafe {
2666 Group {
2667 name: CStr::from_ptr((*gr).gr_name).to_string_lossy().into_owned(),
2668 gid: Gid::from_raw((*gr).gr_gid),
2669 mem: Group::members((*gr).gr_mem)
2670 }
2671 }
2672 }
2673 }
2674
2675 #[cfg(not(target_os = "redox"))] // RedoxFS does not support passwd
2676 impl Group {
members(mem: *mut *mut c_char) -> Vec<String>2677 unsafe fn members(mem: *mut *mut c_char) -> Vec<String> {
2678 let mut ret = Vec::new();
2679
2680 for i in 0.. {
2681 let u = mem.offset(i);
2682 if (*u).is_null() {
2683 break;
2684 } else {
2685 let s = CStr::from_ptr(*u).to_string_lossy().into_owned();
2686 ret.push(s);
2687 }
2688 }
2689
2690 ret
2691 }
2692
from_anything<F>(f: F) -> Result<Option<Self>> where F: Fn(*mut libc::group, *mut libc::c_char, libc::size_t, *mut *mut libc::group) -> libc::c_int2693 fn from_anything<F>(f: F) -> Result<Option<Self>>
2694 where
2695 F: Fn(*mut libc::group,
2696 *mut libc::c_char,
2697 libc::size_t,
2698 *mut *mut libc::group) -> libc::c_int
2699 {
2700 let buflimit = 16384;
2701 let bufsize = match sysconf(SysconfVar::GETGR_R_SIZE_MAX) {
2702 Ok(Some(n)) => n as usize,
2703 Ok(None) | Err(_) => buflimit as usize,
2704 };
2705
2706 let mut cbuf = Vec::with_capacity(bufsize);
2707 let mut grp = mem::MaybeUninit::<libc::group>::uninit();
2708 let mut res = ptr::null_mut();
2709
2710 loop {
2711 let error = f(grp.as_mut_ptr(), cbuf.as_mut_ptr(), cbuf.capacity(), &mut res);
2712 if error == 0 {
2713 if res.is_null() {
2714 return Ok(None);
2715 } else {
2716 let grp = unsafe { grp.assume_init() };
2717 return Ok(Some(Group::from(&grp)));
2718 }
2719 } else if Errno::last() == Errno::ERANGE {
2720 // Trigger the internal buffer resizing logic.
2721 reserve_double_buffer_size(&mut cbuf, buflimit)?;
2722 } else {
2723 return Err(Error::Sys(Errno::last()));
2724 }
2725 }
2726 }
2727
2728 /// Get a group by GID.
2729 ///
2730 /// Internally, this function calls
2731 /// [getgrgid_r(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getpwuid_r.html)
2732 ///
2733 /// # Examples
2734 ///
2735 // Disable this test on all OS except Linux as root group may not exist.
2736 #[cfg_attr(not(target_os = "linux"), doc = " ```no_run")]
2737 #[cfg_attr(target_os = "linux", doc = " ```")]
2738 /// use nix::unistd::{Gid, Group};
2739 /// // Returns an Result<Option<Group>>, thus the double unwrap.
2740 /// let res = Group::from_gid(Gid::from_raw(0)).unwrap().unwrap();
2741 /// assert!(res.name == "root");
2742 /// ```
from_gid(gid: Gid) -> Result<Option<Self>>2743 pub fn from_gid(gid: Gid) -> Result<Option<Self>> {
2744 Group::from_anything(|grp, cbuf, cap, res| {
2745 unsafe { libc::getgrgid_r(gid.0, grp, cbuf, cap, res) }
2746 })
2747 }
2748
2749 /// Get a group by name.
2750 ///
2751 /// Internally, this function calls
2752 /// [getgrnam_r(3)](http://pubs.opengroup.org/onlinepubs/9699919799/functions/getpwuid_r.html)
2753 ///
2754 /// # Examples
2755 ///
2756 // Disable this test on all OS except Linux as root group may not exist.
2757 #[cfg_attr(not(target_os = "linux"), doc = " ```no_run")]
2758 #[cfg_attr(target_os = "linux", doc = " ```")]
2759 /// use nix::unistd::Group;
2760 /// // Returns an Result<Option<Group>>, thus the double unwrap.
2761 /// let res = Group::from_name("root").unwrap().unwrap();
2762 /// assert!(res.name == "root");
2763 /// ```
from_name(name: &str) -> Result<Option<Self>>2764 pub fn from_name(name: &str) -> Result<Option<Self>> {
2765 let name = CString::new(name).unwrap();
2766 Group::from_anything(|grp, cbuf, cap, res| {
2767 unsafe { libc::getgrnam_r(name.as_ptr(), grp, cbuf, cap, res) }
2768 })
2769 }
2770 }
2771
2772 /// Get the name of the terminal device that is open on file descriptor fd
2773 /// (see [`ttyname(3)`](http://man7.org/linux/man-pages/man3/ttyname.3.html)).
ttyname(fd: RawFd) -> Result<PathBuf>2774 pub fn ttyname(fd: RawFd) -> Result<PathBuf> {
2775 const PATH_MAX: usize = libc::PATH_MAX as usize;
2776 let mut buf = vec![0_u8; PATH_MAX];
2777 let c_buf = buf.as_mut_ptr() as *mut libc::c_char;
2778
2779 let ret = unsafe { libc::ttyname_r(fd, c_buf, buf.len()) };
2780 if ret != 0 {
2781 return Err(Error::Sys(Errno::from_i32(ret)));
2782 }
2783
2784 let nul = buf.iter().position(|c| *c == b'\0').unwrap();
2785 buf.truncate(nul);
2786 Ok(OsString::from_vec(buf).into())
2787 }
2788