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 #else
 186
 187     return 1;
 188 #endif
 189
 190 }
 191
 192 /* Create a new PID file for the current process. */
 193 int pa_pid_file_create(const char *procname) {
 194     int fd = -1;
 195     int ret = -1;
 196     char t[20];
 197     pid_t pid;
 198     size_t l;
 199     char *fn;
 200
 201 #ifdef OS_IS_WIN32
 202     HANDLE process;
 203 #endif
 204
 205     if (!(fn = pa_runtime_path("pid")))
 206         goto fail;
 207
 208     if ((fd = open_pid_file(fn, O_CREAT|O_RDWR)) < 0)
 209         goto fail;
 210
 211     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 212         pa_log_warn("Corrupt PID file, overwriting.");
 213     else if (pid > 0) {
 214
 215 #ifdef OS_IS_WIN32
 216         if ((process = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid)) != NULL) {
 217             CloseHandle(process);
 218 #else
 219         if (kill(pid, 0) >= 0 || errno != ESRCH) {
 220 #endif
 221             int ours = 1;
 222
 223             if (procname)
 224                 if ((ours = proc_name_ours(pid, procname)) < 0)
 225                     goto fail;
 226
 227             if (ours) {
 228                 pa_log("Daemon already running.");
 229                 ret = 1;
 230                 goto fail;
 231             }
 232         }
 233
 234         pa_log_warn("Stale PID file, overwriting.");
 235     }
 236
 237     /* Overwrite the current PID file */
 238     if (lseek(fd, (off_t) 0, SEEK_SET) == (off_t) -1 || ftruncate(fd, (off_t) 0) < 0) {
 239         pa_log("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 240         goto fail;
 241     }
 242
 243     pa_snprintf(t, sizeof(t), "%lu\n", (unsigned long) getpid());
 244     l = strlen(t);
 245
 246     if (pa_loop_write(fd, t, l, NULL) != (ssize_t) l) {
 247         pa_log("Failed to write PID file.");
 248         goto fail;
 249     }
 250
 251     ret = 0;
 252
 253 fail:
 254     if (fd >= 0) {
 255         pa_lock_fd(fd, 0);
 256
 257         if (pa_close(fd) < 0) {
 258             pa_log("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 259             ret = -1;
 260         }
 261     }
 262
 263     pa_xfree(fn);
 264
 265     return ret;
 266 }
 267
 268 /* Remove the PID file, if it is ours */
 269 int pa_pid_file_remove(void) {
 270     int fd = -1;
 271     char *fn;
 272     int ret = -1;
 273     pid_t pid;
 274
 275     if (!(fn = pa_runtime_path("pid")))
 276         goto fail;
 277
 278     if ((fd = open_pid_file(fn, O_RDWR)) < 0) {
 279         pa_log_warn("Failed to open PID file '%s': %s", fn, pa_cstrerror(errno));
 280         goto fail;
 281     }
 282
 283     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 284         goto fail;
 285
 286     if (pid != getpid()) {
 287         pa_log("PID file '%s' not mine!", fn);
 288         goto fail;
 289     }
 290
 291     if (ftruncate(fd, (off_t) 0) < 0) {
 292         pa_log_warn("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 293         goto fail;
 294     }
 295
 296 #ifdef OS_IS_WIN32
 297     pa_lock_fd(fd, 0);
 298     pa_close(fd);
 299     fd = -1;
 300 #endif
 301
 302     if (unlink(fn) < 0) {
 303         pa_log_warn("Failed to remove PID file '%s': %s", fn, pa_cstrerror(errno));
 304         goto fail;
 305     }
 306
 307     ret = 0;
 308
 309 fail:
 310
 311     if (fd >= 0) {
 312         pa_lock_fd(fd, 0);
 313
 314         if (pa_close(fd) < 0) {
 315             pa_log_warn("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 316             ret = -1;
 317         }
 318     }
 319
 320     pa_xfree(fn);
 321
 322     return ret;
 323 }
 324
 325 /* Check whether the daemon is currently running, i.e. if a PID file
 326  * exists and the PID therein too. Returns 0 on succcess, -1
 327  * otherwise. If pid is non-NULL and a running daemon was found,
 328  * return its PID therein */
 329 int pa_pid_file_check_running(pid_t *pid, const char *procname) {
 330     return pa_pid_file_kill(0, pid, procname);
 331 }
 332
 333 #ifndef OS_IS_WIN32
 334
 335 /* Kill a current running daemon. Return non-zero on success, -1
 336  * otherwise. If successful *pid contains the PID of the daemon
 337  * process. */
 338 int pa_pid_file_kill(int sig, pid_t *pid, const char *procname) {
 339     int fd = -1;
 340     char *fn;
 341     int ret = -1;
 342     pid_t _pid;
 343 #ifdef __linux__
 344     char *e = NULL;
 345 #endif
 346
 347     if (!pid)
 348         pid = &_pid;
 349
 350     if (!(fn = pa_runtime_path("pid")))
 351         goto fail;
 352
 353     if ((fd = open_pid_file(fn, O_RDONLY)) < 0) {
 354
 355         if (errno == ENOENT)
 356             errno = ESRCH;
 357
 358         goto fail;
 359     }
 360
 361     if ((*pid = read_pid(fn, fd)) == (pid_t) -1)
 362         goto fail;
 363
 364     if (procname) {
 365         int ours;
 366
 367         if ((ours = proc_name_ours(*pid, procname)) < 0)
 368             goto fail;
 369
 370         if (!ours) {
 371             errno = ESRCH;
 372             goto fail;
 373         }
 374     }
 375
 376     ret = kill(*pid, sig);
 377
 378 fail:
 379
 380     if (fd >= 0) {
 381         int saved_errno = errno;
 382         pa_lock_fd(fd, 0);
 383         pa_close(fd);
 384         errno = saved_errno;
 385     }
 386
 387 #ifdef __linux__
 388     pa_xfree(e);
 389 #endif
 390
 391     pa_xfree(fn);
 392
 393     return ret;
 394
 395 }
 396
 397 #else /* OS_IS_WIN32 */
 398
 399 int pa_pid_file_kill(int sig, pid_t *pid, const char *exe_name) {
 400     return -1;
 401 }
 402
 403 #endif