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
  46 #include <pulsecore/core-error.h>
  47 #include <pulsecore/core-util.h>
  48 #include <pulsecore/log.h>
  49 #include <pulsecore/macro.h>
  50
  51 #include "pid.h"
  52
  53 /* Read the PID data from the file descriptor fd, and return it. If no
  54  * pid could be read, return 0, on failure (pid_t) -1 */
  55 static pid_t read_pid(const char *fn, int fd) {
  56     ssize_t r;
  57     char t[20], *e;
  58     uint32_t pid;
  59
  60     pa_assert(fn);
  61     pa_assert(fd >= 0);
  62
  63     if ((r = pa_loop_read(fd, t, sizeof(t)-1, NULL)) < 0) {
  64         pa_log_warn("Failed to read PID file '%s': %s", fn, pa_cstrerror(errno));
  65         return (pid_t) -1;
  66     }
  67
  68     if (r == 0)
  69         return (pid_t) 0;
  70
  71     t[r] = 0;
  72     if ((e = strchr(t, '\n')))
  73         *e = 0;
  74
  75     if (pa_atou(t, &pid) < 0) {
  76         pa_log_warn("Failed to parse PID file '%s'", fn);
  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|O_NOCTTY
  92 #ifdef O_NOFOLLOW
  93                        |O_NOFOLLOW
  94 #endif
  95                        , S_IRUSR|S_IWUSR
  96              )) < 0) {
  97             if (mode != O_RDONLY || errno != ENOENT)
  98                 pa_log_warn("Failed to open PID file '%s': %s", fn, pa_cstrerror(errno));
  99             goto fail;
 100         }
 101
 102         /* Try to lock the file. If that fails, go without */
 103         if (pa_lock_fd(fd, 1) < 0)
 104             goto fail;
 105
 106         if (fstat(fd, &st) < 0) {
 107             pa_log_warn("Failed to fstat() PID file '%s': %s", fn, pa_cstrerror(errno));
 108             goto fail;
 109         }
 110
 111         /* Does the file still exist in the file system? When ye, w're done, otherwise restart */
 112         if (st.st_nlink >= 1)
 113             break;
 114
 115         if (pa_lock_fd(fd, 0) < 0)
 116             goto fail;
 117
 118         if (pa_close(fd) < 0) {
 119             pa_log_warn("Failed to close file '%s': %s", fn, pa_cstrerror(errno));
 120             fd = -1;
 121             goto fail;
 122         }
 123
 124         fd = -1;
 125     }
 126
 127     return fd;
 128
 129 fail:
 130
 131     if (fd >= 0) {
 132         pa_lock_fd(fd, 0);
 133         pa_close(fd);
 134     }
 135
 136     return -1;
 137 }
 138
 139 /* Create a new PID file for the current process. */
 140 int pa_pid_file_create(void) {
 141     int fd = -1;
 142     int ret = -1;
 143     char fn[PATH_MAX];
 144     char t[20];
 145     pid_t pid;
 146     size_t l;
 147
 148 #ifdef OS_IS_WIN32
 149     HANDLE process;
 150 #endif
 151
 152     pa_runtime_path("pid", fn, sizeof(fn));
 153
 154     if ((fd = open_pid_file(fn, O_CREAT|O_RDWR)) < 0)
 155         goto fail;
 156
 157     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 158         pa_log_warn("Corrupt PID file, overwriting.");
 159     else if (pid > 0) {
 160 #ifdef OS_IS_WIN32
 161         if ((process = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid)) != NULL) {
 162             CloseHandle(process);
 163 #else
 164         if (kill(pid, 0) >= 0 || errno != ESRCH) {
 165 #endif
 166             pa_log("Daemon already running.");
 167             goto fail;
 168         }
 169
 170         pa_log_warn("Stale PID file, overwriting.");
 171     }
 172
 173     /* Overwrite the current PID file */
 174     if (lseek(fd, 0, SEEK_SET) == (off_t) -1 || ftruncate(fd, 0) < 0) {
 175         pa_log("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 176         goto fail;
 177     }
 178
 179     pa_snprintf(t, sizeof(t), "%lu\n", (unsigned long) getpid());
 180     l = strlen(t);
 181
 182     if (pa_loop_write(fd, t, l, NULL) != (ssize_t) l) {
 183         pa_log("Failed to write PID file.");
 184         goto fail;
 185     }
 186
 187     ret = 0;
 188
 189 fail:
 190     if (fd >= 0) {
 191         pa_lock_fd(fd, 0);
 192
 193         if (pa_close(fd) < 0) {
 194             pa_log("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 195             ret = -1;
 196         }
 197     }
 198
 199     return ret;
 200 }
 201
 202 /* Remove the PID file, if it is ours */
 203 int pa_pid_file_remove(void) {
 204     int fd = -1;
 205     char fn[PATH_MAX];
 206     int ret = -1;
 207     pid_t pid;
 208
 209     pa_runtime_path("pid", fn, sizeof(fn));
 210
 211     if ((fd = open_pid_file(fn, O_RDWR)) < 0) {
 212         pa_log_warn("Failed to open PID file '%s': %s", fn, pa_cstrerror(errno));
 213         goto fail;
 214     }
 215
 216     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 217         goto fail;
 218
 219     if (pid != getpid()) {
 220         pa_log("PID file '%s' not mine!", fn);
 221         goto fail;
 222     }
 223
 224     if (ftruncate(fd, 0) < 0) {
 225         pa_log_warn("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 226         goto fail;
 227     }
 228
 229 #ifdef OS_IS_WIN32
 230     pa_lock_fd(fd, 0);
 231     close(fd);
 232     fd = -1;
 233 #endif
 234
 235     if (unlink(fn) < 0) {
 236         pa_log_warn("Failed to remove PID file '%s': %s", fn, pa_cstrerror(errno));
 237         goto fail;
 238     }
 239
 240     ret = 0;
 241
 242 fail:
 243
 244     if (fd >= 0) {
 245         pa_lock_fd(fd, 0);
 246
 247         if (pa_close(fd) < 0) {
 248             pa_log_warn("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 249             ret = -1;
 250         }
 251     }
 252
 253     return ret;
 254 }
 255
 256 /* Check whether the daemon is currently running, i.e. if a PID file
 257  * exists and the PID therein too. Returns 0 on succcess, -1
 258  * otherwise. If pid is non-NULL and a running daemon was found,
 259  * return its PID therein */
 260 int pa_pid_file_check_running(pid_t *pid) {
 261     return pa_pid_file_kill(0, pid);
 262 }
 263
 264 #ifndef OS_IS_WIN32
 265
 266 /* Kill a current running daemon. Return non-zero on success, -1
 267  * otherwise. If successful *pid contains the PID of the daemon
 268  * process. */
 269 int pa_pid_file_kill(int sig, pid_t *pid) {
 270     int fd = -1;
 271     char fn[PATH_MAX];
 272     int ret = -1;
 273     pid_t _pid;
 274
 275     if (!pid)
 276         pid = &_pid;
 277
 278     pa_runtime_path("pid", fn, sizeof(fn));
 279
 280     if ((fd = open_pid_file(fn, O_RDONLY)) < 0)
 281         goto fail;
 282
 283     if ((*pid = read_pid(fn, fd)) == (pid_t) -1)
 284         goto fail;
 285
 286     ret = kill(*pid, sig);
 287
 288 fail:
 289
 290     if (fd >= 0) {
 291         pa_lock_fd(fd, 0);
 292         pa_close(fd);
 293     }
 294
 295     return ret;
 296
 297 }
 298
 299 #else /* OS_IS_WIN32 */
 300
 301 int pa_pid_file_kill(int sig, pid_t *pid) {
 302     return -1;
 303 }
 304
 305 #endif