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         return (pid_t) -1;
  77     }
  78
  79     return (pid_t) pid;
  80 }
  81
  82 static int open_pid_file(const char *fn, int mode) {
  83     int fd = -1;
  84
  85     pa_assert(fn);
  86
  87     for (;;) {
  88         struct stat st;
  89
  90         if ((fd = open(fn, mode
  91 #ifdef O_NOCTTY
  92                        |O_NOCTTY
  93 #endif
  94 #ifdef O_NOFOLLOW
  95                        |O_NOFOLLOW
  96 #endif
  97                        , S_IRUSR|S_IWUSR
  98              )) < 0) {
  99             if (mode != O_RDONLY || errno != ENOENT)
 100                 pa_log_warn("Failed to open PID file '%s': %s", fn, pa_cstrerror(errno));
 101             goto fail;
 102         }
 103
 104         /* Try to lock the file. If that fails, go without */
 105         if (pa_lock_fd(fd, 1) < 0)
 106             goto fail;
 107
 108         if (fstat(fd, &st) < 0) {
 109             pa_log_warn("Failed to fstat() PID file '%s': %s", fn, pa_cstrerror(errno));
 110             goto fail;
 111         }
 112
 113         /* Does the file still exist in the file system? When ye, w're done, otherwise restart */
 114         if (st.st_nlink >= 1)
 115             break;
 116
 117         if (pa_lock_fd(fd, 0) < 0)
 118             goto fail;
 119
 120         if (pa_close(fd) < 0) {
 121             pa_log_warn("Failed to close file '%s': %s", fn, pa_cstrerror(errno));
 122             fd = -1;
 123             goto fail;
 124         }
 125
 126         fd = -1;
 127     }
 128
 129     return fd;
 130
 131 fail:
 132
 133     if (fd >= 0) {
 134         pa_lock_fd(fd, 0);
 135         pa_close(fd);
 136     }
 137
 138     return -1;
 139 }
 140
 141 static int proc_name_ours(pid_t pid, const char *procname) {
 142 #ifdef __linux__
 143     char bn[PATH_MAX];
 144     FILE *f;
 145
 146     pa_snprintf(bn, sizeof(bn), "/proc/%lu/stat", (unsigned long) pid);
 147
 148     if (!(f = fopen(bn, "r"))) {
 149         pa_log_info("Failed to open %s: %s", bn, pa_cstrerror(errno));
 150         return -1;
 151     } else {
 152         char *expected;
 153         pa_bool_t good;
 154         char stored[64];
 155
 156         if (!(fgets(stored, sizeof(stored), f))) {
 157             pa_log_info("Failed to read from %s: %s", bn, feof(f) ? "EOF" : pa_cstrerror(errno));
 158             fclose(f);
 159             return -1;
 160         }
 161
 162         fclose(f);
 163
 164         expected = pa_sprintf_malloc("%lu (%s)", (unsigned long) pid, procname);
 165         good = pa_startswith(stored, expected);
 166         pa_xfree(expected);
 167
 168 #if !defined(__OPTIMIZE__)
 169         if (!good) {
 170             /* libtool likes to rename our binary names ... */
 171             expected = pa_sprintf_malloc("%lu (lt-%s)", (unsigned long) pid, procname);
 172             good = pa_startswith(stored, expected);
 173             pa_xfree(expected);
 174         }
 175 #endif
 176
 177         return !!good;
 178     }
 179 #endif
 180
 181     return 1;
 182 }
 183
 184 /* Create a new PID file for the current process. */
 185 int pa_pid_file_create(const char *procname) {
 186     int fd = -1;
 187     int ret = -1;
 188     char t[20];
 189     pid_t pid;
 190     size_t l;
 191     char *fn;
 192
 193 #ifdef OS_IS_WIN32
 194     HANDLE process;
 195 #endif
 196
 197     if (!(fn = pa_runtime_path("pid")))
 198         goto fail;
 199
 200     if ((fd = open_pid_file(fn, O_CREAT|O_RDWR)) < 0)
 201         goto fail;
 202
 203     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 204         pa_log_warn("Corrupt PID file, overwriting.");
 205     else if (pid > 0) {
 206
 207 #ifdef OS_IS_WIN32
 208         if ((process = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid)) != NULL) {
 209             CloseHandle(process);
 210 #else
 211         if (kill(pid, 0) >= 0 || errno != ESRCH) {
 212 #endif
 213             int ours = 1;
 214
 215             if (procname)
 216                 if ((ours = proc_name_ours(pid, procname)) < 0)
 217                     goto fail;
 218
 219             if (ours) {
 220                 pa_log("Daemon already running.");
 221                 ret = 1;
 222                 goto fail;
 223             }
 224         }
 225
 226         pa_log_warn("Stale PID file, overwriting.");
 227     }
 228
 229     /* Overwrite the current PID file */
 230     if (lseek(fd, 0, SEEK_SET) == (off_t) -1 || ftruncate(fd, 0) < 0) {
 231         pa_log("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 232         goto fail;
 233     }
 234
 235     pa_snprintf(t, sizeof(t), "%lu\n", (unsigned long) getpid());
 236     l = strlen(t);
 237
 238     if (pa_loop_write(fd, t, l, NULL) != (ssize_t) l) {
 239         pa_log("Failed to write PID file.");
 240         goto fail;
 241     }
 242
 243     ret = 0;
 244
 245 fail:
 246     if (fd >= 0) {
 247         pa_lock_fd(fd, 0);
 248
 249         if (pa_close(fd) < 0) {
 250             pa_log("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 251             ret = -1;
 252         }
 253     }
 254
 255     pa_xfree(fn);
 256
 257     return ret;
 258 }
 259
 260 /* Remove the PID file, if it is ours */
 261 int pa_pid_file_remove(void) {
 262     int fd = -1;
 263     char *fn;
 264     int ret = -1;
 265     pid_t pid;
 266
 267     if (!(fn = pa_runtime_path("pid")))
 268         goto fail;
 269
 270     if ((fd = open_pid_file(fn, O_RDWR)) < 0) {
 271         pa_log_warn("Failed to open PID file '%s': %s", fn, pa_cstrerror(errno));
 272         goto fail;
 273     }
 274
 275     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 276         goto fail;
 277
 278     if (pid != getpid()) {
 279         pa_log("PID file '%s' not mine!", fn);
 280         goto fail;
 281     }
 282
 283     if (ftruncate(fd, 0) < 0) {
 284         pa_log_warn("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 285         goto fail;
 286     }
 287
 288 #ifdef OS_IS_WIN32
 289     pa_lock_fd(fd, 0);
 290     pa_close(fd);
 291     fd = -1;
 292 #endif
 293
 294     if (unlink(fn) < 0) {
 295         pa_log_warn("Failed to remove PID file '%s': %s", fn, pa_cstrerror(errno));
 296         goto fail;
 297     }
 298
 299     ret = 0;
 300
 301 fail:
 302
 303     if (fd >= 0) {
 304         pa_lock_fd(fd, 0);
 305
 306         if (pa_close(fd) < 0) {
 307             pa_log_warn("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 308             ret = -1;
 309         }
 310     }
 311
 312     pa_xfree(fn);
 313
 314     return ret;
 315 }
 316
 317 /* Check whether the daemon is currently running, i.e. if a PID file
 318  * exists and the PID therein too. Returns 0 on succcess, -1
 319  * otherwise. If pid is non-NULL and a running daemon was found,
 320  * return its PID therein */
 321 int pa_pid_file_check_running(pid_t *pid, const char *procname) {
 322     return pa_pid_file_kill(0, pid, procname);
 323 }
 324
 325 #ifndef OS_IS_WIN32
 326
 327 /* Kill a current running daemon. Return non-zero on success, -1
 328  * otherwise. If successful *pid contains the PID of the daemon
 329  * process. */
 330 int pa_pid_file_kill(int sig, pid_t *pid, const char *procname) {
 331     int fd = -1;
 332     char *fn;
 333     int ret = -1;
 334     pid_t _pid;
 335 #ifdef __linux__
 336     char *e = NULL;
 337 #endif
 338
 339     if (!pid)
 340         pid = &_pid;
 341
 342     if (!(fn = pa_runtime_path("pid")))
 343         goto fail;
 344
 345     if ((fd = open_pid_file(fn, O_RDONLY)) < 0)
 346         goto fail;
 347
 348     if ((*pid = read_pid(fn, fd)) == (pid_t) -1)
 349         goto fail;
 350
 351     if (procname) {
 352         int ours;
 353
 354         if ((ours = proc_name_ours(*pid, procname)) < 0)
 355             goto fail;
 356
 357         if (!ours)
 358             goto fail;
 359     }
 360
 361     ret = kill(*pid, sig);
 362
 363 fail:
 364
 365     if (fd >= 0) {
 366         pa_lock_fd(fd, 0);
 367         pa_close(fd);
 368     }
 369
 370 #ifdef __linux__
 371     pa_xfree(e);
 372 #endif
 373
 374     pa_xfree(fn);
 375
 376     return ret;
 377
 378 }
 379
 380 #else /* OS_IS_WIN32 */
 381
 382 int pa_pid_file_kill(int sig, pid_t *pid, const char *exe_name) {
 383     return -1;
 384 }
 385
 386 #endif