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

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