code.delx.au - pulseaudio/blob - src/pulsecore/pid.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2004-2006 Lennart Poettering
   5   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   6
   7   PulseAudio is free software; you can redistribute it and/or modify
   8   it under the terms of the GNU Lesser General Public License as
   9   published by the Free Software Foundation; either version 2 of the
  10   License, or (at your option) any later version.
  11
  12   PulseAudio is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public
  18   License along with PulseAudio; if not, write to the Free Software
  19   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  20   USA.
  21 ***/
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include <config.h>
  25 #endif
  26
  27 #include <fcntl.h>
  28 #include <unistd.h>
  29 #include <errno.h>
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32 #include <string.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <limits.h>
  36 #include <signal.h>
  37
  38 #ifdef HAVE_WINDOWS_H
  39 #include <windows.h>
  40 #endif
  41
  42 #include <pulse/xmalloc.h>
  43 #include <pulse/util.h>
  44
  45 #include <pulsecore/core-error.h>
  46 #include <pulsecore/core-util.h>
  47 #include <pulsecore/log.h>
  48 #include <pulsecore/macro.h>
  49
  50 #include "pid.h"
  51
  52 /* Read the PID data from the file descriptor fd, and return it. If no
  53  * pid could be read, return 0, on failure (pid_t) -1 */
  54 static pid_t read_pid(const char *fn, int fd) {
  55     ssize_t r;
  56     char t[20], *e;
  57     uint32_t pid;
  58
  59     pa_assert(fn);
  60     pa_assert(fd >= 0);
  61
  62     if ((r = pa_loop_read(fd, t, sizeof(t)-1, NULL)) < 0) {
  63         pa_log_warn("Failed to read PID file '%s': %s", fn, pa_cstrerror(errno));
  64         return (pid_t) -1;
  65     }
  66
  67     if (r == 0)
  68         return (pid_t) 0;
  69
  70     t[r] = 0;
  71     if ((e = strchr(t, '\n')))
  72         *e = 0;
  73
  74     if (pa_atou(t, &pid) < 0) {
  75         pa_log_warn("Failed to parse PID file '%s'", fn);
  76         errno = EINVAL;
  77         return (pid_t) -1;
  78     }
  79
  80     return (pid_t) pid;
  81 }
  82
  83 static int open_pid_file(const char *fn, int mode) {
  84     int fd = -1;
  85
  86     pa_assert(fn);
  87
  88     for (;;) {
  89         struct stat st;
  90
  91         if ((fd = open(fn, mode
  92 #ifdef O_NOCTTY
  93                        |O_NOCTTY
  94 #endif
  95 #ifdef O_NOFOLLOW
  96                        |O_NOFOLLOW
  97 #endif
  98                        , S_IRUSR|S_IWUSR
  99              )) < 0) {
 100             if (mode != O_RDONLY || errno != ENOENT)
 101                 pa_log_warn("Failed to open PID file '%s': %s", fn, pa_cstrerror(errno));
 102             goto fail;
 103         }
 104
 105         /* Try to lock the file. If that fails, go without */
 106         if (pa_lock_fd(fd, 1) < 0)
 107             goto fail;
 108
 109         if (fstat(fd, &st) < 0) {
 110             pa_log_warn("Failed to fstat() PID file '%s': %s", fn, pa_cstrerror(errno));
 111             goto fail;
 112         }
 113
 114         /* Does the file still exist in the file system? When yes, we're done, otherwise restart */
 115         if (st.st_nlink >= 1)
 116             break;
 117
 118         if (pa_lock_fd(fd, 0) < 0)
 119             goto fail;
 120
 121         if (pa_close(fd) < 0) {
 122             pa_log_warn("Failed to close file '%s': %s", fn, pa_cstrerror(errno));
 123             fd = -1;
 124             goto fail;
 125         }
 126
 127         fd = -1;
 128     }
 129
 130     return fd;
 131
 132 fail:
 133
 134     if (fd >= 0) {
 135         int saved_errno = errno;
 136         pa_lock_fd(fd, 0);
 137         pa_close(fd);
 138         errno = saved_errno;
 139     }
 140
 141     return -1;
 142 }
 143
 144 static int proc_name_ours(pid_t pid, const char *procname) {
 145 #ifdef __linux__
 146     char bn[PATH_MAX];
 147     FILE *f;
 148
 149     pa_snprintf(bn, sizeof(bn), "/proc/%lu/stat", (unsigned long) pid);
 150
 151     if (!(f = fopen(bn, "r"))) {
 152         pa_log_info("Failed to open %s: %s", bn, pa_cstrerror(errno));
 153         return -1;
 154     } else {
 155         char *expected;
 156         pa_bool_t good;
 157         char stored[64];
 158
 159         if (!(fgets(stored, sizeof(stored), f))) {
 160             int saved_errno = feof(f) ? EINVAL : errno;
 161             pa_log_info("Failed to read from %s: %s", bn, feof(f) ? "EOF" : pa_cstrerror(errno));
 162             fclose(f);
 163
 164             errno = saved_errno;
 165             return -1;
 166         }
 167
 168         fclose(f);
 169
 170         expected = pa_sprintf_malloc("%lu (%s)", (unsigned long) pid, procname);
 171         good = pa_startswith(stored, expected);
 172         pa_xfree(expected);
 173
 174 #if !defined(__OPTIMIZE__)
 175         if (!good) {
 176             /* libtool likes to rename our binary names ... */
 177             expected = pa_sprintf_malloc("%lu (lt-%s)", (unsigned long) pid, procname);
 178             good = pa_startswith(stored, expected);
 179             pa_xfree(expected);
 180         }
 181 #endif
 182
 183         return !!good;
 184     }
 185 #endif
 186
 187     return 1;
 188 }
 189
 190 /* Create a new PID file for the current process. */
 191 int pa_pid_file_create(const char *procname) {
 192     int fd = -1;
 193     int ret = -1;
 194     char t[20];
 195     pid_t pid;
 196     size_t l;
 197     char *fn;
 198
 199 #ifdef OS_IS_WIN32
 200     HANDLE process;
 201 #endif
 202
 203     if (!(fn = pa_runtime_path("pid")))
 204         goto fail;
 205
 206     if ((fd = open_pid_file(fn, O_CREAT|O_RDWR)) < 0)
 207         goto fail;
 208
 209     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 210         pa_log_warn("Corrupt PID file, overwriting.");
 211     else if (pid > 0) {
 212
 213 #ifdef OS_IS_WIN32
 214         if ((process = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid)) != NULL) {
 215             CloseHandle(process);
 216 #else
 217         if (kill(pid, 0) >= 0 || errno != ESRCH) {
 218 #endif
 219             int ours = 1;
 220
 221             if (procname)
 222                 if ((ours = proc_name_ours(pid, procname)) < 0)
 223                     goto fail;
 224
 225             if (ours) {
 226                 pa_log("Daemon already running.");
 227                 ret = 1;
 228                 goto fail;
 229             }
 230         }
 231
 232         pa_log_warn("Stale PID file, overwriting.");
 233     }
 234
 235     /* Overwrite the current PID file */
 236     if (lseek(fd, 0, SEEK_SET) == (off_t) -1 || ftruncate(fd, 0) < 0) {
 237         pa_log("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 238         goto fail;
 239     }
 240
 241     pa_snprintf(t, sizeof(t), "%lu\n", (unsigned long) getpid());
 242     l = strlen(t);
 243
 244     if (pa_loop_write(fd, t, l, NULL) != (ssize_t) l) {
 245         pa_log("Failed to write PID file.");
 246         goto fail;
 247     }
 248
 249     ret = 0;
 250
 251 fail:
 252     if (fd >= 0) {
 253         pa_lock_fd(fd, 0);
 254
 255         if (pa_close(fd) < 0) {
 256             pa_log("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 257             ret = -1;
 258         }
 259     }
 260
 261     pa_xfree(fn);
 262
 263     return ret;
 264 }
 265
 266 /* Remove the PID file, if it is ours */
 267 int pa_pid_file_remove(void) {
 268     int fd = -1;
 269     char *fn;
 270     int ret = -1;
 271     pid_t pid;
 272
 273     if (!(fn = pa_runtime_path("pid")))
 274         goto fail;
 275
 276     if ((fd = open_pid_file(fn, O_RDWR)) < 0) {
 277         pa_log_warn("Failed to open PID file '%s': %s", fn, pa_cstrerror(errno));
 278         goto fail;
 279     }
 280
 281     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 282         goto fail;
 283
 284     if (pid != getpid()) {
 285         pa_log("PID file '%s' not mine!", fn);
 286         goto fail;
 287     }
 288
 289     if (ftruncate(fd, 0) < 0) {
 290         pa_log_warn("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 291         goto fail;
 292     }
 293
 294 #ifdef OS_IS_WIN32
 295     pa_lock_fd(fd, 0);
 296     pa_close(fd);
 297     fd = -1;
 298 #endif
 299
 300     if (unlink(fn) < 0) {
 301         pa_log_warn("Failed to remove PID file '%s': %s", fn, pa_cstrerror(errno));
 302         goto fail;
 303     }
 304
 305     ret = 0;
 306
 307 fail:
 308
 309     if (fd >= 0) {
 310         pa_lock_fd(fd, 0);
 311
 312         if (pa_close(fd) < 0) {
 313             pa_log_warn("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 314             ret = -1;
 315         }
 316     }
 317
 318     pa_xfree(fn);
 319
 320     return ret;
 321 }
 322
 323 /* Check whether the daemon is currently running, i.e. if a PID file
 324  * exists and the PID therein too. Returns 0 on succcess, -1
 325  * otherwise. If pid is non-NULL and a running daemon was found,
 326  * return its PID therein */
 327 int pa_pid_file_check_running(pid_t *pid, const char *procname) {
 328     return pa_pid_file_kill(0, pid, procname);
 329 }
 330
 331 #ifndef OS_IS_WIN32
 332
 333 /* Kill a current running daemon. Return non-zero on success, -1
 334  * otherwise. If successful *pid contains the PID of the daemon
 335  * process. */
 336 int pa_pid_file_kill(int sig, pid_t *pid, const char *procname) {
 337     int fd = -1;
 338     char *fn;
 339     int ret = -1;
 340     pid_t _pid;
 341 #ifdef __linux__
 342     char *e = NULL;
 343 #endif
 344
 345     if (!pid)
 346         pid = &_pid;
 347
 348     if (!(fn = pa_runtime_path("pid")))
 349         goto fail;
 350
 351     if ((fd = open_pid_file(fn, O_RDONLY)) < 0) {
 352
 353         if (errno == ENOENT)
 354             errno = ESRCH;
 355
 356         goto fail;
 357     }
 358
 359     if ((*pid = read_pid(fn, fd)) == (pid_t) -1)
 360         goto fail;
 361
 362     if (procname) {
 363         int ours;
 364
 365         if ((ours = proc_name_ours(*pid, procname)) < 0)
 366             goto fail;
 367
 368         if (!ours) {
 369             errno = ESRCH;
 370             goto fail;
 371         }
 372     }
 373
 374     ret = kill(*pid, sig);
 375
 376 fail:
 377
 378     if (fd >= 0) {
 379         int saved_errno = errno;
 380         pa_lock_fd(fd, 0);
 381         pa_close(fd);
 382         errno = saved_errno;
 383     }
 384
 385 #ifdef __linux__
 386     pa_xfree(e);
 387 #endif
 388
 389     pa_xfree(fn);
 390
 391     return ret;
 392
 393 }
 394
 395 #else /* OS_IS_WIN32 */
 396
 397 int pa_pid_file_kill(int sig, pid_t *pid, const char *exe_name) {
 398     return -1;
 399 }
 400
 401 #endif