1//===- Unix/Process.cpp - Unix Process Implementation --------- -*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file provides the generic Unix implementation of the Process class.
10//
11//===----------------------------------------------------------------------===//
12
13#include "Unix.h"
14#include "llvm/ADT/Hashing.h"
15#include "llvm/ADT/StringRef.h"
16#include "llvm/Config/config.h"
17#include "llvm/Support/ManagedStatic.h"
18#include <mutex>
19#if HAVE_FCNTL_H
20#include <fcntl.h>
21#endif
22#ifdef HAVE_SYS_TIME_H
23#include <sys/time.h>
24#endif
25#ifdef HAVE_SYS_RESOURCE_H
26#include <sys/resource.h>
27#endif
28#ifdef HAVE_SYS_STAT_H
29#include <sys/stat.h>
30#endif
31#if HAVE_SIGNAL_H
32#include <signal.h>
33#endif
34#if defined(HAVE_MALLINFO)
35#include <malloc.h>
36#endif
37#if defined(HAVE_MALLCTL)
38#include <malloc_np.h>
39#endif
40#ifdef HAVE_MALLOC_MALLOC_H
41#include <malloc/malloc.h>
42#endif
43#ifdef HAVE_SYS_IOCTL_H
44#  include <sys/ioctl.h>
45#endif
46#ifdef HAVE_TERMIOS_H
47#  include <termios.h>
48#endif
49
50//===----------------------------------------------------------------------===//
51//=== WARNING: Implementation here must contain only generic UNIX code that
52//===          is guaranteed to work on *all* UNIX variants.
53//===----------------------------------------------------------------------===//
54
55using namespace llvm;
56using namespace sys;
57
58static std::pair<std::chrono::microseconds, std::chrono::microseconds> getRUsageTimes() {
59#if defined(HAVE_GETRUSAGE)
60  struct rusage RU;
61  ::getrusage(RUSAGE_SELF, &RU);
62  return { toDuration(RU.ru_utime), toDuration(RU.ru_stime) };
63#else
64#warning Cannot get usage times on this platform
65  return { std::chrono::microseconds::zero(), std::chrono::microseconds::zero() };
66#endif
67}
68
69Process::Pid Process::getProcessId() {
70  static_assert(sizeof(Pid) >= sizeof(pid_t),
71                "Process::Pid should be big enough to store pid_t");
72  return Pid(::getpid());
73}
74
75// On Cygwin, getpagesize() returns 64k(AllocationGranularity) and
76// offset in mmap(3) should be aligned to the AllocationGranularity.
77Expected<unsigned> Process::getPageSize() {
78#if defined(HAVE_GETPAGESIZE)
79  static const int page_size = ::getpagesize();
80#elif defined(HAVE_SYSCONF)
81  static long page_size = ::sysconf(_SC_PAGE_SIZE);
82#else
83#error Cannot get the page size on this machine
84#endif
85  if (page_size == -1)
86    return errorCodeToError(std::error_code(errno, std::generic_category()));
87
88  return static_cast<unsigned>(page_size);
89}
90
91size_t Process::GetMallocUsage() {
92#if defined(HAVE_MALLINFO)
93  struct mallinfo mi;
94  mi = ::mallinfo();
95  return mi.uordblks;
96#elif defined(HAVE_MALLOC_ZONE_STATISTICS) && defined(HAVE_MALLOC_MALLOC_H)
97  malloc_statistics_t Stats;
98  malloc_zone_statistics(malloc_default_zone(), &Stats);
99  return Stats.size_in_use;   // darwin
100#elif defined(HAVE_MALLCTL)
101  size_t alloc, sz;
102  sz = sizeof(size_t);
103  if (mallctl("stats.allocated", &alloc, &sz, NULL, 0) == 0)
104    return alloc;
105  return 0;
106#elif defined(HAVE_SBRK)
107  // Note this is only an approximation and more closely resembles
108  // the value returned by mallinfo in the arena field.
109  static char *StartOfMemory = reinterpret_cast<char*>(::sbrk(0));
110  char *EndOfMemory = (char*)sbrk(0);
111  if (EndOfMemory != ((char*)-1) && StartOfMemory != ((char*)-1))
112    return EndOfMemory - StartOfMemory;
113  return 0;
114#else
115#warning Cannot get malloc info on this platform
116  return 0;
117#endif
118}
119
120void Process::GetTimeUsage(TimePoint<> &elapsed, std::chrono::nanoseconds &user_time,
121                           std::chrono::nanoseconds &sys_time) {
122  elapsed = std::chrono::system_clock::now();
123  std::tie(user_time, sys_time) = getRUsageTimes();
124}
125
126#if defined(HAVE_MACH_MACH_H) && !defined(__GNU__)
127#include <mach/mach.h>
128#endif
129
130// Some LLVM programs such as bugpoint produce core files as a normal part of
131// their operation. To prevent the disk from filling up, this function
132// does what's necessary to prevent their generation.
133void Process::PreventCoreFiles() {
134#if HAVE_SETRLIMIT
135  struct rlimit rlim;
136  rlim.rlim_cur = rlim.rlim_max = 0;
137  setrlimit(RLIMIT_CORE, &rlim);
138#endif
139
140#if defined(HAVE_MACH_MACH_H) && !defined(__GNU__)
141  // Disable crash reporting on Mac OS X 10.0-10.4
142
143  // get information about the original set of exception ports for the task
144  mach_msg_type_number_t Count = 0;
145  exception_mask_t OriginalMasks[EXC_TYPES_COUNT];
146  exception_port_t OriginalPorts[EXC_TYPES_COUNT];
147  exception_behavior_t OriginalBehaviors[EXC_TYPES_COUNT];
148  thread_state_flavor_t OriginalFlavors[EXC_TYPES_COUNT];
149  kern_return_t err =
150    task_get_exception_ports(mach_task_self(), EXC_MASK_ALL, OriginalMasks,
151                             &Count, OriginalPorts, OriginalBehaviors,
152                             OriginalFlavors);
153  if (err == KERN_SUCCESS) {
154    // replace each with MACH_PORT_NULL.
155    for (unsigned i = 0; i != Count; ++i)
156      task_set_exception_ports(mach_task_self(), OriginalMasks[i],
157                               MACH_PORT_NULL, OriginalBehaviors[i],
158                               OriginalFlavors[i]);
159  }
160
161  // Disable crash reporting on Mac OS X 10.5
162  signal(SIGABRT, _exit);
163  signal(SIGILL,  _exit);
164  signal(SIGFPE,  _exit);
165  signal(SIGSEGV, _exit);
166  signal(SIGBUS,  _exit);
167#endif
168
169  coreFilesPrevented = true;
170}
171
172Optional<std::string> Process::GetEnv(StringRef Name) {
173  std::string NameStr = Name.str();
174  const char *Val = ::getenv(NameStr.c_str());
175  if (!Val)
176    return None;
177  return std::string(Val);
178}
179
180namespace {
181class FDCloser {
182public:
183  FDCloser(int &FD) : FD(FD), KeepOpen(false) {}
184  void keepOpen() { KeepOpen = true; }
185  ~FDCloser() {
186    if (!KeepOpen && FD >= 0)
187      ::close(FD);
188  }
189
190private:
191  FDCloser(const FDCloser &) = delete;
192  void operator=(const FDCloser &) = delete;
193
194  int &FD;
195  bool KeepOpen;
196};
197}
198
199std::error_code Process::FixupStandardFileDescriptors() {
200  int NullFD = -1;
201  FDCloser FDC(NullFD);
202  const int StandardFDs[] = {STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO};
203  for (int StandardFD : StandardFDs) {
204    struct stat st;
205    errno = 0;
206    if (RetryAfterSignal(-1, ::fstat, StandardFD, &st) < 0) {
207      assert(errno && "expected errno to be set if fstat failed!");
208      // fstat should return EBADF if the file descriptor is closed.
209      if (errno != EBADF)
210        return std::error_code(errno, std::generic_category());
211    }
212    // if fstat succeeds, move on to the next FD.
213    if (!errno)
214      continue;
215    assert(errno == EBADF && "expected errno to have EBADF at this point!");
216
217    if (NullFD < 0) {
218      // Call ::open in a lambda to avoid overload resolution in
219      // RetryAfterSignal when open is overloaded, such as in Bionic.
220      auto Open = [&]() { return ::open("/dev/null", O_RDWR); };
221      if ((NullFD = RetryAfterSignal(-1, Open)) < 0)
222        return std::error_code(errno, std::generic_category());
223    }
224
225    if (NullFD == StandardFD)
226      FDC.keepOpen();
227    else if (dup2(NullFD, StandardFD) < 0)
228      return std::error_code(errno, std::generic_category());
229  }
230  return std::error_code();
231}
232
233std::error_code Process::SafelyCloseFileDescriptor(int FD) {
234  // Create a signal set filled with *all* signals.
235  sigset_t FullSet;
236  if (sigfillset(&FullSet) < 0)
237    return std::error_code(errno, std::generic_category());
238  // Atomically swap our current signal mask with a full mask.
239  sigset_t SavedSet;
240#if LLVM_ENABLE_THREADS
241  if (int EC = pthread_sigmask(SIG_SETMASK, &FullSet, &SavedSet))
242    return std::error_code(EC, std::generic_category());
243#else
244  if (sigprocmask(SIG_SETMASK, &FullSet, &SavedSet) < 0)
245    return std::error_code(errno, std::generic_category());
246#endif
247  // Attempt to close the file descriptor.
248  // We need to save the error, if one occurs, because our subsequent call to
249  // pthread_sigmask might tamper with errno.
250  int ErrnoFromClose = 0;
251  if (::close(FD) < 0)
252    ErrnoFromClose = errno;
253  // Restore the signal mask back to what we saved earlier.
254  int EC = 0;
255#if LLVM_ENABLE_THREADS
256  EC = pthread_sigmask(SIG_SETMASK, &SavedSet, nullptr);
257#else
258  if (sigprocmask(SIG_SETMASK, &SavedSet, nullptr) < 0)
259    EC = errno;
260#endif
261  // The error code from close takes precedence over the one from
262  // pthread_sigmask.
263  if (ErrnoFromClose)
264    return std::error_code(ErrnoFromClose, std::generic_category());
265  return std::error_code(EC, std::generic_category());
266}
267
268bool Process::StandardInIsUserInput() {
269  return FileDescriptorIsDisplayed(STDIN_FILENO);
270}
271
272bool Process::StandardOutIsDisplayed() {
273  return FileDescriptorIsDisplayed(STDOUT_FILENO);
274}
275
276bool Process::StandardErrIsDisplayed() {
277  return FileDescriptorIsDisplayed(STDERR_FILENO);
278}
279
280bool Process::FileDescriptorIsDisplayed(int fd) {
281#if HAVE_ISATTY
282  return isatty(fd);
283#else
284  // If we don't have isatty, just return false.
285  return false;
286#endif
287}
288
289static unsigned getColumns() {
290  // If COLUMNS is defined in the environment, wrap to that many columns.
291  if (const char *ColumnsStr = std::getenv("COLUMNS")) {
292    int Columns = std::atoi(ColumnsStr);
293    if (Columns > 0)
294      return Columns;
295  }
296
297  // We used to call ioctl TIOCGWINSZ to determine the width. It is considered
298  // unuseful.
299  return 0;
300}
301
302unsigned Process::StandardOutColumns() {
303  if (!StandardOutIsDisplayed())
304    return 0;
305
306  return getColumns();
307}
308
309unsigned Process::StandardErrColumns() {
310  if (!StandardErrIsDisplayed())
311    return 0;
312
313  return getColumns();
314}
315
316#ifdef LLVM_ENABLE_TERMINFO
317// We manually declare these extern functions because finding the correct
318// headers from various terminfo, curses, or other sources is harder than
319// writing their specs down.
320extern "C" int setupterm(char *term, int filedes, int *errret);
321extern "C" struct term *set_curterm(struct term *termp);
322extern "C" int del_curterm(struct term *termp);
323extern "C" int tigetnum(char *capname);
324#endif
325
326#ifdef LLVM_ENABLE_TERMINFO
327static ManagedStatic<std::mutex> TermColorMutex;
328#endif
329
330static bool terminalHasColors(int fd) {
331#ifdef LLVM_ENABLE_TERMINFO
332  // First, acquire a global lock because these C routines are thread hostile.
333  std::lock_guard<std::mutex> G(*TermColorMutex);
334
335  int errret = 0;
336  if (setupterm(nullptr, fd, &errret) != 0)
337    // Regardless of why, if we can't get terminfo, we shouldn't try to print
338    // colors.
339    return false;
340
341  // Test whether the terminal as set up supports color output. How to do this
342  // isn't entirely obvious. We can use the curses routine 'has_colors' but it
343  // would be nice to avoid a dependency on curses proper when we can make do
344  // with a minimal terminfo parsing library. Also, we don't really care whether
345  // the terminal supports the curses-specific color changing routines, merely
346  // if it will interpret ANSI color escape codes in a reasonable way. Thus, the
347  // strategy here is just to query the baseline colors capability and if it
348  // supports colors at all to assume it will translate the escape codes into
349  // whatever range of colors it does support. We can add more detailed tests
350  // here if users report them as necessary.
351  //
352  // The 'tigetnum' routine returns -2 or -1 on errors, and might return 0 if
353  // the terminfo says that no colors are supported.
354  bool HasColors = tigetnum(const_cast<char *>("colors")) > 0;
355
356  // Now extract the structure allocated by setupterm and free its memory
357  // through a really silly dance.
358  struct term *termp = set_curterm(nullptr);
359  (void)del_curterm(termp); // Drop any errors here.
360
361  // Return true if we found a color capabilities for the current terminal.
362  if (HasColors)
363    return true;
364#else
365  // When the terminfo database is not available, check if the current terminal
366  // is one of terminals that are known to support ANSI color escape codes.
367  if (const char *TermStr = std::getenv("TERM")) {
368    return StringSwitch<bool>(TermStr)
369      .Case("ansi", true)
370      .Case("cygwin", true)
371      .Case("linux", true)
372      .StartsWith("screen", true)
373      .StartsWith("xterm", true)
374      .StartsWith("vt100", true)
375      .StartsWith("rxvt", true)
376      .EndsWith("color", true)
377      .Default(false);
378  }
379#endif
380
381  // Otherwise, be conservative.
382  return false;
383}
384
385bool Process::FileDescriptorHasColors(int fd) {
386  // A file descriptor has colors if it is displayed and the terminal has
387  // colors.
388  return FileDescriptorIsDisplayed(fd) && terminalHasColors(fd);
389}
390
391bool Process::StandardOutHasColors() {
392  return FileDescriptorHasColors(STDOUT_FILENO);
393}
394
395bool Process::StandardErrHasColors() {
396  return FileDescriptorHasColors(STDERR_FILENO);
397}
398
399void Process::UseANSIEscapeCodes(bool /*enable*/) {
400  // No effect.
401}
402
403bool Process::ColorNeedsFlush() {
404  // No, we use ANSI escape sequences.
405  return false;
406}
407
408const char *Process::OutputColor(char code, bool bold, bool bg) {
409  return colorcodes[bg?1:0][bold?1:0][code&7];
410}
411
412const char *Process::OutputBold(bool bg) {
413  return "\033[1m";
414}
415
416const char *Process::OutputReverse() {
417  return "\033[7m";
418}
419
420const char *Process::ResetColor() {
421  return "\033[0m";
422}
423
424#if !HAVE_DECL_ARC4RANDOM
425static unsigned GetRandomNumberSeed() {
426  // Attempt to get the initial seed from /dev/urandom, if possible.
427  int urandomFD = open("/dev/urandom", O_RDONLY);
428
429  if (urandomFD != -1) {
430    unsigned seed;
431    // Don't use a buffered read to avoid reading more data
432    // from /dev/urandom than we need.
433    int count = read(urandomFD, (void *)&seed, sizeof(seed));
434
435    close(urandomFD);
436
437    // Return the seed if the read was successful.
438    if (count == sizeof(seed))
439      return seed;
440  }
441
442  // Otherwise, swizzle the current time and the process ID to form a reasonable
443  // seed.
444  const auto Now = std::chrono::high_resolution_clock::now();
445  return hash_combine(Now.time_since_epoch().count(), ::getpid());
446}
447#endif
448
449unsigned llvm::sys::Process::GetRandomNumber() {
450#if HAVE_DECL_ARC4RANDOM
451  return arc4random();
452#else
453  static int x = (static_cast<void>(::srand(GetRandomNumberSeed())), 0);
454  (void)x;
455  return ::rand();
456#endif
457}
458