util/oslib-posix.c

   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 #include "qemu/osdep.h"
  30 #include <termios.h>
  31
  32 #include <glib/gprintf.h>
  33
  34 #include "sysemu/sysemu.h"
  35 #include "trace.h"
  36 #include "qapi/error.h"
  37 #include "qemu/sockets.h"
  38 #include <libgen.h>
  39 #include <sys/signal.h>
  40 #include "qemu/cutils.h"
  41
  42 #ifdef CONFIG_LINUX
  43 #include <sys/syscall.h>
  44 #endif
  45
  46 #ifdef __FreeBSD__
  47 #include <sys/sysctl.h>
  48 #include <sys/user.h>
  49 #include <libutil.h>
  50 #endif
  51
  52 #include "qemu/mmap-alloc.h"
  53
  54 #ifdef CONFIG_DEBUG_STACK_USAGE
  55 #include "qemu/error-report.h"
  56 #endif
  57
  58 int qemu_get_thread_id(void)
  59 {
  60 #if defined(__linux__)
  61     return syscall(SYS_gettid);
  62 #else
  63     return getpid();
  64 #endif
  65 }
  66
  67 int qemu_daemon(int nochdir, int noclose)
  68 {
  69     return daemon(nochdir, noclose);
  70 }
  71
  72 void *qemu_oom_check(void *ptr)
  73 {
  74     if (ptr == NULL) {
  75         fprintf(stderr, "Failed to allocate memory: %s\n", strerror(errno));
  76         abort();
  77     }
  78     return ptr;
  79 }
  80
  81 void *qemu_try_memalign(size_t alignment, size_t size)
  82 {
  83     void *ptr;
  84
  85     if (alignment < sizeof(void*)) {
  86         alignment = sizeof(void*);
  87     }
  88
  89 #if defined(_POSIX_C_SOURCE) && !defined(__sun__)
  90     int ret;
  91     ret = posix_memalign(&ptr, alignment, size);
  92     if (ret != 0) {
  93         errno = ret;
  94         ptr = NULL;
  95     }
  96 #elif defined(CONFIG_BSD)
  97     ptr = valloc(size);
  98 #else
  99     ptr = memalign(alignment, size);
 100 #endif
 101     trace_qemu_memalign(alignment, size, ptr);
 102     return ptr;
 103 }
 104
 105 void *qemu_memalign(size_t alignment, size_t size)
 106 {
 107     return qemu_oom_check(qemu_try_memalign(alignment, size));
 108 }
 109
 110 /* alloc shared memory pages */
 111 void *qemu_anon_ram_alloc(size_t size, uint64_t *alignment)
 112 {
 113     size_t align = QEMU_VMALLOC_ALIGN;
 114     void *ptr = qemu_ram_mmap(-1, size, align, false);
 115
 116     if (ptr == MAP_FAILED) {
 117         return NULL;
 118     }
 119
 120     if (alignment) {
 121         *alignment = align;
 122     }
 123
 124     trace_qemu_anon_ram_alloc(size, ptr);
 125     return ptr;
 126 }
 127
 128 void qemu_vfree(void *ptr)
 129 {
 130     trace_qemu_vfree(ptr);
 131     free(ptr);
 132 }
 133
 134 void qemu_anon_ram_free(void *ptr, size_t size)
 135 {
 136     trace_qemu_anon_ram_free(ptr, size);
 137     qemu_ram_munmap(ptr, size);
 138 }
 139
 140 void qemu_set_block(int fd)
 141 {
 142     int f;
 143     f = fcntl(fd, F_GETFL);
 144     fcntl(fd, F_SETFL, f & ~O_NONBLOCK);
 145 }
 146
 147 void qemu_set_nonblock(int fd)
 148 {
 149     int f;
 150     f = fcntl(fd, F_GETFL);
 151     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 152 }
 153
 154 int socket_set_fast_reuse(int fd)
 155 {
 156     int val = 1, ret;
 157
 158     ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
 159                      (const char *)&val, sizeof(val));
 160
 161     assert(ret == 0);
 162
 163     return ret;
 164 }
 165
 166 void qemu_set_cloexec(int fd)
 167 {
 168     int f;
 169     f = fcntl(fd, F_GETFD);
 170     fcntl(fd, F_SETFD, f | FD_CLOEXEC);
 171 }
 172
 173 /*
 174  * Creates a pipe with FD_CLOEXEC set on both file descriptors
 175  */
 176 int qemu_pipe(int pipefd[2])
 177 {
 178     int ret;
 179
 180 #ifdef CONFIG_PIPE2
 181     ret = pipe2(pipefd, O_CLOEXEC);
 182     if (ret != -1 || errno != ENOSYS) {
 183         return ret;
 184     }
 185 #endif
 186     ret = pipe(pipefd);
 187     if (ret == 0) {
 188         qemu_set_cloexec(pipefd[0]);
 189         qemu_set_cloexec(pipefd[1]);
 190     }
 191
 192     return ret;
 193 }
 194
 195 int qemu_utimens(const char *path, const struct timespec *times)
 196 {
 197     struct timeval tv[2], tv_now;
 198     struct stat st;
 199     int i;
 200 #ifdef CONFIG_UTIMENSAT
 201     int ret;
 202
 203     ret = utimensat(AT_FDCWD, path, times, AT_SYMLINK_NOFOLLOW);
 204     if (ret != -1 || errno != ENOSYS) {
 205         return ret;
 206     }
 207 #endif
 208     /* Fallback: use utimes() instead of utimensat() */
 209
 210     /* happy if special cases */
 211     if (times[0].tv_nsec == UTIME_OMIT && times[1].tv_nsec == UTIME_OMIT) {
 212         return 0;
 213     }
 214     if (times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) {
 215         return utimes(path, NULL);
 216     }
 217
 218     /* prepare for hard cases */
 219     if (times[0].tv_nsec == UTIME_NOW || times[1].tv_nsec == UTIME_NOW) {
 220         gettimeofday(&tv_now, NULL);
 221     }
 222     if (times[0].tv_nsec == UTIME_OMIT || times[1].tv_nsec == UTIME_OMIT) {
 223         stat(path, &st);
 224     }
 225
 226     for (i = 0; i < 2; i++) {
 227         if (times[i].tv_nsec == UTIME_NOW) {
 228             tv[i].tv_sec = tv_now.tv_sec;
 229             tv[i].tv_usec = tv_now.tv_usec;
 230         } else if (times[i].tv_nsec == UTIME_OMIT) {
 231             tv[i].tv_sec = (i == 0) ? st.st_atime : st.st_mtime;
 232             tv[i].tv_usec = 0;
 233         } else {
 234             tv[i].tv_sec = times[i].tv_sec;
 235             tv[i].tv_usec = times[i].tv_nsec / 1000;
 236         }
 237     }
 238
 239     return utimes(path, &tv[0]);
 240 }
 241
 242 char *
 243 qemu_get_local_state_pathname(const char *relative_pathname)
 244 {
 245     return g_strdup_printf("%s/%s", CONFIG_QEMU_LOCALSTATEDIR,
 246                            relative_pathname);
 247 }
 248
 249 void qemu_set_tty_echo(int fd, bool echo)
 250 {
 251     struct termios tty;
 252
 253     tcgetattr(fd, &tty);
 254
 255     if (echo) {
 256         tty.c_lflag |= ECHO | ECHONL | ICANON | IEXTEN;
 257     } else {
 258         tty.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
 259     }
 260
 261     tcsetattr(fd, TCSANOW, &tty);
 262 }
 263
 264 static char exec_dir[PATH_MAX];
 265
 266 void qemu_init_exec_dir(const char *argv0)
 267 {
 268     char *dir;
 269     char *p = NULL;
 270     char buf[PATH_MAX];
 271
 272     assert(!exec_dir[0]);
 273
 274 #if defined(__linux__)
 275     {
 276         int len;
 277         len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);
 278         if (len > 0) {
 279             buf[len] = 0;
 280             p = buf;
 281         }
 282     }
 283 #elif defined(__FreeBSD__)
 284     {
 285         static int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, -1};
 286         size_t len = sizeof(buf) - 1;
 287
 288         *buf = '\0';
 289         if (!sysctl(mib, ARRAY_SIZE(mib), buf, &len, NULL, 0) &&
 290             *buf) {
 291             buf[sizeof(buf) - 1] = '\0';
 292             p = buf;
 293         }
 294     }
 295 #endif
 296     /* If we don't have any way of figuring out the actual executable
 297        location then try argv[0].  */
 298     if (!p) {
 299         if (!argv0) {
 300             return;
 301         }
 302         p = realpath(argv0, buf);
 303         if (!p) {
 304             return;
 305         }
 306     }
 307     dir = g_path_get_dirname(p);
 308
 309     pstrcpy(exec_dir, sizeof(exec_dir), dir);
 310
 311     g_free(dir);
 312 }
 313
 314 char *qemu_get_exec_dir(void)
 315 {
 316     return g_strdup(exec_dir);
 317 }
 318
 319 static sigjmp_buf sigjump;
 320
 321 static void sigbus_handler(int signal)
 322 {
 323     siglongjmp(sigjump, 1);
 324 }
 325
 326 void os_mem_prealloc(int fd, char *area, size_t memory, Error **errp)
 327 {
 328     int ret;
 329     struct sigaction act, oldact;
 330     sigset_t set, oldset;
 331
 332     memset(&act, 0, sizeof(act));
 333     act.sa_handler = &sigbus_handler;
 334     act.sa_flags = 0;
 335
 336     ret = sigaction(SIGBUS, &act, &oldact);
 337     if (ret) {
 338         error_setg_errno(errp, errno,
 339             "os_mem_prealloc: failed to install signal handler");
 340         return;
 341     }
 342
 343     /* unblock SIGBUS */
 344     sigemptyset(&set);
 345     sigaddset(&set, SIGBUS);
 346     pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
 347
 348     if (sigsetjmp(sigjump, 1)) {
 349         error_setg(errp, "os_mem_prealloc: Insufficient free host memory "
 350             "pages available to allocate guest RAM\n");
 351     } else {
 352         int i;
 353         size_t hpagesize = qemu_fd_getpagesize(fd);
 354         size_t numpages = DIV_ROUND_UP(memory, hpagesize);
 355
 356         /* MAP_POPULATE silently ignores failures */
 357         for (i = 0; i < numpages; i++) {
 358             memset(area + (hpagesize * i), 0, 1);
 359         }
 360     }
 361
 362     ret = sigaction(SIGBUS, &oldact, NULL);
 363     if (ret) {
 364         /* Terminate QEMU since it can't recover from error */
 365         perror("os_mem_prealloc: failed to reinstall signal handler");
 366         exit(1);
 367     }
 368     pthread_sigmask(SIG_SETMASK, &oldset, NULL);
 369 }
 370
 371
 372 static struct termios oldtty;
 373
 374 static void term_exit(void)
 375 {
 376     tcsetattr(0, TCSANOW, &oldtty);
 377 }
 378
 379 static void term_init(void)
 380 {
 381     struct termios tty;
 382
 383     tcgetattr(0, &tty);
 384     oldtty = tty;
 385
 386     tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
 387                           |INLCR|IGNCR|ICRNL|IXON);
 388     tty.c_oflag |= OPOST;
 389     tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
 390     tty.c_cflag &= ~(CSIZE|PARENB);
 391     tty.c_cflag |= CS8;
 392     tty.c_cc[VMIN] = 1;
 393     tty.c_cc[VTIME] = 0;
 394
 395     tcsetattr(0, TCSANOW, &tty);
 396
 397     atexit(term_exit);
 398 }
 399
 400 int qemu_read_password(char *buf, int buf_size)
 401 {
 402     uint8_t ch;
 403     int i, ret;
 404
 405     printf("password: ");
 406     fflush(stdout);
 407     term_init();
 408     i = 0;
 409     for (;;) {
 410         ret = read(0, &ch, 1);
 411         if (ret == -1) {
 412             if (errno == EAGAIN || errno == EINTR) {
 413                 continue;
 414             } else {
 415                 break;
 416             }
 417         } else if (ret == 0) {
 418             ret = -1;
 419             break;
 420         } else {
 421             if (ch == '\r' ||
 422                 ch == '\n') {
 423                 ret = 0;
 424                 break;
 425             }
 426             if (i < (buf_size - 1)) {
 427                 buf[i++] = ch;
 428             }
 429         }
 430     }
 431     term_exit();
 432     buf[i] = '\0';
 433     printf("\n");
 434     return ret;
 435 }
 436
 437
 438 char *qemu_get_pid_name(pid_t pid)
 439 {
 440     char *name = NULL;
 441
 442 #if defined(__FreeBSD__)
 443     /* BSDs don't have /proc, but they provide a nice substitute */
 444     struct kinfo_proc *proc = kinfo_getproc(pid);
 445
 446     if (proc) {
 447         name = g_strdup(proc->ki_comm);
 448         free(proc);
 449     }
 450 #else
 451     /* Assume a system with reasonable procfs */
 452     char *pid_path;
 453     size_t len;
 454
 455     pid_path = g_strdup_printf("/proc/%d/cmdline", pid);
 456     g_file_get_contents(pid_path, &name, &len, NULL);
 457     g_free(pid_path);
 458 #endif
 459
 460     return name;
 461 }
 462
 463
 464 pid_t qemu_fork(Error **errp)
 465 {
 466     sigset_t oldmask, newmask;
 467     struct sigaction sig_action;
 468     int saved_errno;
 469     pid_t pid;
 470
 471     /*
 472      * Need to block signals now, so that child process can safely
 473      * kill off caller's signal handlers without a race.
 474      */
 475     sigfillset(&newmask);
 476     if (pthread_sigmask(SIG_SETMASK, &newmask, &oldmask) != 0) {
 477         error_setg_errno(errp, errno,
 478                          "cannot block signals");
 479         return -1;
 480     }
 481
 482     pid = fork();
 483     saved_errno = errno;
 484
 485     if (pid < 0) {
 486         /* attempt to restore signal mask, but ignore failure, to
 487          * avoid obscuring the fork failure */
 488         (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
 489         error_setg_errno(errp, saved_errno,
 490                          "cannot fork child process");
 491         errno = saved_errno;
 492         return -1;
 493     } else if (pid) {
 494         /* parent process */
 495
 496         /* Restore our original signal mask now that the child is
 497          * safely running. Only documented failures are EFAULT (not
 498          * possible, since we are using just-grabbed mask) or EINVAL
 499          * (not possible, since we are using correct arguments).  */
 500         (void)pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
 501     } else {
 502         /* child process */
 503         size_t i;
 504
 505         /* Clear out all signal handlers from parent so nothing
 506          * unexpected can happen in our child once we unblock
 507          * signals */
 508         sig_action.sa_handler = SIG_DFL;
 509         sig_action.sa_flags = 0;
 510         sigemptyset(&sig_action.sa_mask);
 511
 512         for (i = 1; i < NSIG; i++) {
 513             /* Only possible errors are EFAULT or EINVAL The former
 514              * won't happen, the latter we expect, so no need to check
 515              * return value */
 516             (void)sigaction(i, &sig_action, NULL);
 517         }
 518
 519         /* Unmask all signals in child, since we've no idea what the
 520          * caller's done with their signal mask and don't want to
 521          * propagate that to children */
 522         sigemptyset(&newmask);
 523         if (pthread_sigmask(SIG_SETMASK, &newmask, NULL) != 0) {
 524             Error *local_err = NULL;
 525             error_setg_errno(&local_err, errno,
 526                              "cannot unblock signals");
 527             error_report_err(local_err);
 528             _exit(1);
 529         }
 530     }
 531     return pid;
 532 }
 533
 534 void *qemu_alloc_stack(size_t *sz)
 535 {
 536     void *ptr, *guardpage;
 537 #ifdef CONFIG_DEBUG_STACK_USAGE
 538     void *ptr2;
 539 #endif
 540     size_t pagesz = getpagesize();
 541 #ifdef _SC_THREAD_STACK_MIN
 542     /* avoid stacks smaller than _SC_THREAD_STACK_MIN */
 543     long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN);
 544     *sz = MAX(MAX(min_stack_sz, 0), *sz);
 545 #endif
 546     /* adjust stack size to a multiple of the page size */
 547     *sz = ROUND_UP(*sz, pagesz);
 548     /* allocate one extra page for the guard page */
 549     *sz += pagesz;
 550
 551     ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE,
 552                MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 553     if (ptr == MAP_FAILED) {
 554         abort();
 555     }
 556
 557 #if defined(HOST_IA64)
 558     /* separate register stack */
 559     guardpage = ptr + (((*sz - pagesz) / 2) & ~pagesz);
 560 #elif defined(HOST_HPPA)
 561     /* stack grows up */
 562     guardpage = ptr + *sz - pagesz;
 563 #else
 564     /* stack grows down */
 565     guardpage = ptr;
 566 #endif
 567     if (mprotect(guardpage, pagesz, PROT_NONE) != 0) {
 568         abort();
 569     }
 570
 571 #ifdef CONFIG_DEBUG_STACK_USAGE
 572     for (ptr2 = ptr + pagesz; ptr2 < ptr + *sz; ptr2 += sizeof(uint32_t)) {
 573         *(uint32_t *)ptr2 = 0xdeadbeaf;
 574     }
 575 #endif
 576
 577     return ptr;
 578 }
 579
 580 #ifdef CONFIG_DEBUG_STACK_USAGE
 581 static __thread unsigned int max_stack_usage;
 582 #endif
 583
 584 void qemu_free_stack(void *stack, size_t sz)
 585 {
 586 #ifdef CONFIG_DEBUG_STACK_USAGE
 587     unsigned int usage;
 588     void *ptr;
 589
 590     for (ptr = stack + getpagesize(); ptr < stack + sz;
 591          ptr += sizeof(uint32_t)) {
 592         if (*(uint32_t *)ptr != 0xdeadbeaf) {
 593             break;
 594         }
 595     }
 596     usage = sz - (uintptr_t) (ptr - stack);
 597     if (usage > max_stack_usage) {
 598         error_report("thread %d max stack usage increased from %u to %u",
 599                      qemu_get_thread_id(), max_stack_usage, usage);
 600         max_stack_usage = usage;
 601     }
 602 #endif
 603
 604     munmap(stack, sz);
 605 }