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 /* Create a new PID file for the current process. */
 144 int pa_pid_file_create(void) {
 145     int fd = -1;
 146     int ret = -1;
 147     char fn[PATH_MAX];
 148     char t[20];
 149     pid_t pid;
 150     size_t l;
 151
 152 #ifdef OS_IS_WIN32
 153     HANDLE process;
 154 #endif
 155
 156     pa_runtime_path("pid", fn, sizeof(fn));
 157
 158     if ((fd = open_pid_file(fn, O_CREAT|O_RDWR)) < 0)
 159         goto fail;
 160
 161     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 162         pa_log_warn("Corrupt PID file, overwriting.");
 163     else if (pid > 0) {
 164 #ifdef OS_IS_WIN32
 165         if ((process = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid)) != NULL) {
 166             CloseHandle(process);
 167 #else
 168         if (kill(pid, 0) >= 0 || errno != ESRCH) {
 169 #endif
 170             pa_log("Daemon already running.");
 171             goto fail;
 172         }
 173
 174         pa_log_warn("Stale PID file, overwriting.");
 175     }
 176
 177     /* Overwrite the current PID file */
 178     if (lseek(fd, 0, SEEK_SET) == (off_t) -1 || ftruncate(fd, 0) < 0) {
 179         pa_log("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 180         goto fail;
 181     }
 182
 183     pa_snprintf(t, sizeof(t), "%lu\n", (unsigned long) getpid());
 184     l = strlen(t);
 185
 186     if (pa_loop_write(fd, t, l, NULL) != (ssize_t) l) {
 187         pa_log("Failed to write PID file.");
 188         goto fail;
 189     }
 190
 191     ret = 0;
 192
 193 fail:
 194     if (fd >= 0) {
 195         pa_lock_fd(fd, 0);
 196
 197         if (pa_close(fd) < 0) {
 198             pa_log("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 199             ret = -1;
 200         }
 201     }
 202
 203     return ret;
 204 }
 205
 206 /* Remove the PID file, if it is ours */
 207 int pa_pid_file_remove(void) {
 208     int fd = -1;
 209     char fn[PATH_MAX];
 210     int ret = -1;
 211     pid_t pid;
 212
 213     pa_runtime_path("pid", fn, sizeof(fn));
 214
 215     if ((fd = open_pid_file(fn, O_RDWR)) < 0) {
 216         pa_log_warn("Failed to open PID file '%s': %s", fn, pa_cstrerror(errno));
 217         goto fail;
 218     }
 219
 220     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 221         goto fail;
 222
 223     if (pid != getpid()) {
 224         pa_log("PID file '%s' not mine!", fn);
 225         goto fail;
 226     }
 227
 228     if (ftruncate(fd, 0) < 0) {
 229         pa_log_warn("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 230         goto fail;
 231     }
 232
 233 #ifdef OS_IS_WIN32
 234     pa_lock_fd(fd, 0);
 235     close(fd);
 236     fd = -1;
 237 #endif
 238
 239     if (unlink(fn) < 0) {
 240         pa_log_warn("Failed to remove PID file '%s': %s", fn, pa_cstrerror(errno));
 241         goto fail;
 242     }
 243
 244     ret = 0;
 245
 246 fail:
 247
 248     if (fd >= 0) {
 249         pa_lock_fd(fd, 0);
 250
 251         if (pa_close(fd) < 0) {
 252             pa_log_warn("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 253             ret = -1;
 254         }
 255     }
 256
 257     return ret;
 258 }
 259
 260 /* Check whether the daemon is currently running, i.e. if a PID file
 261  * exists and the PID therein too. Returns 0 on succcess, -1
 262  * otherwise. If pid is non-NULL and a running daemon was found,
 263  * return its PID therein */
 264 int pa_pid_file_check_running(pid_t *pid, const char *binary_name) {
 265     return pa_pid_file_kill(0, pid, binary_name);
 266 }
 267
 268 #ifndef OS_IS_WIN32
 269
 270 /* Kill a current running daemon. Return non-zero on success, -1
 271  * otherwise. If successful *pid contains the PID of the daemon
 272  * process. */
 273 int pa_pid_file_kill(int sig, pid_t *pid, const char *binary_name) {
 274     int fd = -1;
 275     char fn[PATH_MAX];
 276     int ret = -1;
 277     pid_t _pid;
 278 #ifdef __linux__
 279     char *e = NULL;
 280 #endif
 281     if (!pid)
 282         pid = &_pid;
 283
 284     pa_runtime_path("pid", fn, sizeof(fn));
 285
 286     if ((fd = open_pid_file(fn, O_RDONLY)) < 0)
 287         goto fail;
 288
 289     if ((*pid = read_pid(fn, fd)) == (pid_t) -1)
 290         goto fail;
 291
 292 #ifdef __linux__
 293     if (binary_name) {
 294         pa_snprintf(fn, sizeof(fn), "/proc/%lu/exe", (unsigned long) pid);
 295
 296         if ((e = pa_readlink(fn))) {
 297             char *f = pa_path_get_filename(e);
 298             if (strcmp(f, binary_name)
 299 #if defined(__OPTIMIZE__)
 300                 /* libtool likes to rename our binary names ... */
 301                 && !(pa_startswith(f, "lt-") && strcmp(f+3, binary_name) == 0)
 302 #endif
 303             )
 304                 goto fail;
 305         }
 306     }
 307 #endif
 308
 309     ret = kill(*pid, sig);
 310
 311 fail:
 312
 313     if (fd >= 0) {
 314         pa_lock_fd(fd, 0);
 315         pa_close(fd);
 316     }
 317
 318 #ifdef __linux__
 319     pa_xfree(e);
 320 #endif
 321
 322     return ret;
 323
 324 }
 325
 326 #else /* OS_IS_WIN32 */
 327
 328 int pa_pid_file_kill(int sig, pid_t *pid, const char *exe_name) {
 329     return -1;
 330 }
 331
 332 #endif