1 /* 2 * os-posix-lib.c 3 * 4 * Copyright (c) 2003-2008 Fabrice Bellard 5 * Copyright (c) 2010 Red Hat, Inc. 6 * 7 * QEMU library functions on POSIX which are shared between QEMU and 8 * the QEMU tools. 9 * 10 * Permission is hereby granted, free of charge, to any person obtaining a copy 11 * of this software and associated documentation files (the "Software"), to deal 12 * in the Software without restriction, including without limitation the rights 13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 14 * copies of the Software, and to permit persons to whom the Software is 15 * furnished to do so, subject to the following conditions: 16 * 17 * The above copyright notice and this permission notice shall be included in 18 * all copies or substantial portions of the Software. 19 * 20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 26 * THE SOFTWARE. 27 */ 28 29 /* The following block of code temporarily renames the daemon() function so the 30 compiler does not see the warning associated with it in stdlib.h on OSX */ 31 #ifdef __APPLE__ 32 #define daemon qemu_fake_daemon_function 33 #include <stdlib.h> 34 #undef daemon 35 extern int daemon(int, int); 36 #endif 37 38 #if defined(__linux__) && (defined(__x86_64__) || defined(__arm__)) 39 /* Use 2 MiB alignment so transparent hugepages can be used by KVM. 40 Valgrind does not support alignments larger than 1 MiB, 41 therefore we need special code which handles running on Valgrind. */ 42 # define QEMU_VMALLOC_ALIGN (512 * 4096) 43 #elif defined(__linux__) && defined(__s390x__) 44 /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ 45 # define QEMU_VMALLOC_ALIGN (256 * 4096) 46 #else 47 # define QEMU_VMALLOC_ALIGN getpagesize() 48 #endif 49 #define HUGETLBFS_MAGIC 0x958458f6 50 51 #include <termios.h> 52 #include <unistd.h> 53 54 #include <glib/gprintf.h> 55 56 #include "config-host.h" 57 #include "sysemu/sysemu.h" 58 #include "trace.h" 59 #include "qemu/sockets.h" 60 #include <sys/mman.h> 61 #include <libgen.h> 62 #include <setjmp.h> 63 #include <sys/signal.h> 64 65 #ifdef CONFIG_LINUX 66 #include <sys/syscall.h> 67 #include <sys/vfs.h> 68 #endif 69 70 #ifdef __FreeBSD__ 71 #include <sys/sysctl.h> 72 #endif 73 74 int qemu_get_thread_id(void) 75 { 76 #if defined(__linux__) 77 return syscall(SYS_gettid); 78 #else 79 return getpid(); 80 #endif 81 } 82 83 int qemu_daemon(int nochdir, int noclose) 84 { 85 return daemon(nochdir, noclose); 86 } 87 88 void *qemu_oom_check(void *ptr) 89 { 90 if (ptr == NULL) { 91 fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno)); 92 abort(); 93 } 94 return ptr; 95 } 96 97 void *qemu_try_memalign(size_t alignment, size_t size) 98 { 99 void *ptr; 100 101 if (alignment < sizeof(void*)) { 102 alignment = sizeof(void*); 103 } 104 105 #if defined(_POSIX_C_SOURCE) && !defined(__sun__) 106 int ret; 107 ret = posix_memalign(&ptr, alignment, size); 108 if (ret != 0) { 109 errno = ret; 110 ptr = NULL; 111 } 112 #elif defined(CONFIG_BSD) 113 ptr = valloc(size); 114 #else 115 ptr = memalign(alignment, size); 116 #endif 117 trace_qemu_memalign(alignment, size, ptr); 118 return ptr; 119 } 120 121 void *qemu_memalign(size_t alignment, size_t size) 122 { 123 return qemu_oom_check(qemu_try_memalign(alignment, size)); 124 } 125 126 /* alloc shared memory pages */ 127 void *qemu_anon_ram_alloc(size_t size) 128 { 129 size_t align = QEMU_VMALLOC_ALIGN; 130 size_t total = size + align - getpagesize(); 131 void *ptr = mmap(0, total, PROT_READ | PROT_WRITE, 132 MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); 133 size_t offset = QEMU_ALIGN_UP((uintptr_t)ptr, align) - (uintptr_t)ptr; 134 135 if (ptr == MAP_FAILED) { 136 return NULL; 137 } 138 139 ptr += offset; 140 total -= offset; 141 142 if (offset > 0) { 143 munmap(ptr - offset, offset); 144 } 145 if (total > size) { 146 munmap(ptr + size, total - size); 147 } 148 149 trace_qemu_anon_ram_alloc(size, ptr); 150 return ptr; 151 } 152 153 void qemu_vfree(void *ptr) 154 { 155 trace_qemu_vfree(ptr); 156 free(ptr); 157 } 158 159 void qemu_anon_ram_free(void *ptr, size_t size) 160 { 161 trace_qemu_anon_ram_free(ptr, size); 162 if (ptr) { 163 munmap(ptr, size); 164 } 165 } 166 167 void qemu_set_block(int fd) 168 { 169 int f; 170 f = fcntl(fd, F_GETFL); 171 fcntl(fd, F_SETFL, f & ~O_NONBLOCK); 172 } 173 174 void qemu_set_nonblock(int fd) 175 { 176 int f; 177 f = fcntl(fd, F_GETFL); 178 fcntl(fd, F_SETFL, f | O_NONBLOCK); 179 } 180 181 int socket_set_fast_reuse(int fd) 182 { 183 int val = 1, ret; 184 185 ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, 186 (const char *)&val, sizeof(val)); 187 188 assert(ret == 0); 189 190 return ret; 191 } 192 193 void qemu_set_cloexec(int fd) 194 { 195 int f; 196 f = fcntl(fd, F_GETFD); 197 fcntl(fd, F_SETFD, f | FD_CLOEXEC); 198 } 199 200 /* 201 * Creates a pipe with FD_CLOEXEC set on both file descriptors 202 */ 203 int qemu_pipe(int pipefd[2]) 204 { 205 int ret; 206 207 #ifdef CONFIG_PIPE2 208 ret = pipe2(pipefd, O_CLOEXEC); 209 if (ret != -1 || errno != ENOSYS) { 210 return ret; 211 } 212 #endif 213 ret = pipe(pipefd); 214 if (ret == 0) { 215 qemu_set_cloexec(pipefd[0]); 216 qemu_set_cloexec(pipefd[1]); 217 } 218 219 return ret; 220 } 221 222 int qemu_utimens(const char *path, const struct timespec *times) 223 { 224 struct timeval tv[2], tv_now; 225 struct stat st; 226 int i; 227 #ifdef CONFIG_UTIMENSAT 228 int ret; 229 230 ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW); 231 if (ret != -1 || errno != ENOSYS) { 232 return ret; 233 } 234 #endif 235 /* Fallback: use utimes() instead of utimensat() */ 236 237 /* happy if special cases */ 238 if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) { 239 return 0; 240 } 241 if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) { 242 return utimes(path, NULL); 243 } 244 245 /* prepare for hard cases */ 246 if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) { 247 gettimeofday(&tv_now, NULL); 248 } 249 if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) { 250 stat(path, &st); 251 } 252 253 for (i = 0; i < 2; i++) { 254 if (times[i].tv_nsec == UTIME_NOW) { 255 tv[i].tv_sec = tv_now.tv_sec; 256 tv[i].tv_usec = tv_now.tv_usec; 257 } else if (times[i].tv_nsec == UTIME_OMIT) { 258 tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime; 259 tv[i].tv_usec = 0; 260 } else { 261 tv[i].tv_sec = times[i].tv_sec; 262 tv[i].tv_usec = times[i].tv_nsec / 1000; 263 } 264 } 265 266 return utimes(path, &tv[0]); 267 } 268 269 char * 270 qemu_get_local_state_pathname(const char *relative_pathname) 271 { 272 return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR, 273 relative_pathname); 274 } 275 276 void qemu_set_tty_echo(int fd, bool echo) 277 { 278 struct termios tty; 279 280 tcgetattr(fd, &tty); 281 282 if (echo) { 283 tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN; 284 } else { 285 tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN); 286 } 287 288 tcsetattr(fd, TCSANOW, &tty); 289 } 290 291 static char exec_dir[PATH_MAX]; 292 293 void qemu_init_exec_dir(const char *argv0) 294 { 295 char *dir; 296 char *p = NULL; 297 char buf[PATH_MAX]; 298 299 assert(!exec_dir[0]); 300 301 #if defined(__linux__) 302 { 303 int len; 304 len = readlink("/proc/self/exe", buf, sizeof(buf) - 1); 305 if (len > 0) { 306 buf[len] = 0; 307 p = buf; 308 } 309 } 310 #elif defined(__FreeBSD__) 311 { 312 static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1}; 313 size_t len = sizeof(buf) - 1; 314 315 *buf = '\0'; 316 if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) && 317 *buf) { 318 buf[sizeof(buf) - 1] = '\0'; 319 p = buf; 320 } 321 } 322 #endif 323 /* If we don't have any way of figuring out the actual executable 324 location then try argv[0]. */ 325 if (!p) { 326 if (!argv0) { 327 return; 328 } 329 p = realpath(argv0, buf); 330 if (!p) { 331 return; 332 } 333 } 334 dir = dirname(p); 335 336 pstrcpy(exec_dir, sizeof(exec_dir), dir); 337 } 338 339 char *qemu_get_exec_dir(void) 340 { 341 return g_strdup(exec_dir); 342 } 343 344 static sigjmp_buf sigjump; 345 346 static void sigbus_handler(int signal) 347 { 348 siglongjmp(sigjump, 1); 349 } 350 351 static size_t fd_getpagesize(int fd) 352 { 353 #ifdef CONFIG_LINUX 354 struct statfs fs; 355 int ret; 356 357 if (fd != -1) { 358 do { 359 ret = fstatfs(fd, &fs); 360 } while (ret != 0 && errno == EINTR); 361 362 if (ret == 0 && fs.f_type == HUGETLBFS_MAGIC) { 363 return fs.f_bsize; 364 } 365 } 366 #endif 367 368 return getpagesize(); 369 } 370 371 void os_mem_prealloc(int fd, char *area, size_t memory) 372 { 373 int ret; 374 struct sigaction act, oldact; 375 sigset_t set, oldset; 376 377 memset(&act, 0, sizeof(act)); 378 act.sa_handler = &sigbus_handler; 379 act.sa_flags = 0; 380 381 ret = sigaction(SIGBUS, &act, &oldact); 382 if (ret) { 383 perror("os_mem_prealloc: failed to install signal handler"); 384 exit(1); 385 } 386 387 /* unblock SIGBUS */ 388 sigemptyset(&set); 389 sigaddset(&set, SIGBUS); 390 pthread_sigmask(SIG_UNBLOCK, &set, &oldset); 391 392 if (sigsetjmp(sigjump, 1)) { 393 fprintf(stderr, "os_mem_prealloc: failed to preallocate pages\n"); 394 exit(1); 395 } else { 396 int i; 397 size_t hpagesize = fd_getpagesize(fd); 398 399 /* MAP_POPULATE silently ignores failures */ 400 memory = (memory + hpagesize - 1) & -hpagesize; 401 for (i = 0; i < (memory / hpagesize); i++) { 402 memset(area + (hpagesize * i), 0, 1); 403 } 404 405 ret = sigaction(SIGBUS, &oldact, NULL); 406 if (ret) { 407 perror("os_mem_prealloc: failed to reinstall signal handler"); 408 exit(1); 409 } 410 411 pthread_sigmask(SIG_SETMASK, &oldset, NULL); 412 } 413 } 414