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
  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 ye, w'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         pa_lock_fd(fd, 0);
 136         pa_close(fd);
 137     }
 138
 139     return -1;
 140 }
 141
 142 /* Create a new PID file for the current process. */
 143 int pa_pid_file_create(void) {
 144     int fd = -1;
 145     int ret = -1;
 146     char fn[PATH_MAX];
 147     char t[20];
 148     pid_t pid;
 149     size_t l;
 150
 151 #ifdef OS_IS_WIN32
 152     HANDLE process;
 153 #endif
 154
 155     pa_runtime_path("pid", fn, sizeof(fn));
 156
 157     if ((fd = open_pid_file(fn, O_CREAT|O_RDWR)) < 0)
 158         goto fail;
 159
 160     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 161         pa_log_warn("Corrupt PID file, overwriting.");
 162     else if (pid > 0) {
 163 #ifdef OS_IS_WIN32
 164         if ((process = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, pid)) != NULL) {
 165             CloseHandle(process);
 166 #else
 167         if (kill(pid, 0) >= 0 || errno != ESRCH) {
 168 #endif
 169             pa_log("Daemon already running.");
 170             goto fail;
 171         }
 172
 173         pa_log_warn("Stale PID file, overwriting.");
 174     }
 175
 176     /* Overwrite the current PID file */
 177     if (lseek(fd, 0, SEEK_SET) == (off_t) -1 || ftruncate(fd, 0) < 0) {
 178         pa_log("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 179         goto fail;
 180     }
 181
 182     pa_snprintf(t, sizeof(t), "%lu\n", (unsigned long) getpid());
 183     l = strlen(t);
 184
 185     if (pa_loop_write(fd, t, l, NULL) != (ssize_t) l) {
 186         pa_log("Failed to write PID file.");
 187         goto fail;
 188     }
 189
 190     ret = 0;
 191
 192 fail:
 193     if (fd >= 0) {
 194         pa_lock_fd(fd, 0);
 195
 196         if (pa_close(fd) < 0) {
 197             pa_log("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 198             ret = -1;
 199         }
 200     }
 201
 202     return ret;
 203 }
 204
 205 /* Remove the PID file, if it is ours */
 206 int pa_pid_file_remove(void) {
 207     int fd = -1;
 208     char fn[PATH_MAX];
 209     int ret = -1;
 210     pid_t pid;
 211
 212     pa_runtime_path("pid", fn, sizeof(fn));
 213
 214     if ((fd = open_pid_file(fn, O_RDWR)) < 0) {
 215         pa_log_warn("Failed to open PID file '%s': %s", fn, pa_cstrerror(errno));
 216         goto fail;
 217     }
 218
 219     if ((pid = read_pid(fn, fd)) == (pid_t) -1)
 220         goto fail;
 221
 222     if (pid != getpid()) {
 223         pa_log("PID file '%s' not mine!", fn);
 224         goto fail;
 225     }
 226
 227     if (ftruncate(fd, 0) < 0) {
 228         pa_log_warn("Failed to truncate PID file '%s': %s", fn, pa_cstrerror(errno));
 229         goto fail;
 230     }
 231
 232 #ifdef OS_IS_WIN32
 233     pa_lock_fd(fd, 0);
 234     close(fd);
 235     fd = -1;
 236 #endif
 237
 238     if (unlink(fn) < 0) {
 239         pa_log_warn("Failed to remove PID file '%s': %s", fn, pa_cstrerror(errno));
 240         goto fail;
 241     }
 242
 243     ret = 0;
 244
 245 fail:
 246
 247     if (fd >= 0) {
 248         pa_lock_fd(fd, 0);
 249
 250         if (pa_close(fd) < 0) {
 251             pa_log_warn("Failed to close PID file '%s': %s", fn, pa_cstrerror(errno));
 252             ret = -1;
 253         }
 254     }
 255
 256     return ret;
 257 }
 258
 259 /* Check whether the daemon is currently running, i.e. if a PID file
 260  * exists and the PID therein too. Returns 0 on succcess, -1
 261  * otherwise. If pid is non-NULL and a running daemon was found,
 262  * return its PID therein */
 263 int pa_pid_file_check_running(pid_t *pid) {
 264     return pa_pid_file_kill(0, pid);
 265 }
 266
 267 #ifndef OS_IS_WIN32
 268
 269 /* Kill a current running daemon. Return non-zero on success, -1
 270  * otherwise. If successful *pid contains the PID of the daemon
 271  * process. */
 272 int pa_pid_file_kill(int sig, pid_t *pid) {
 273     int fd = -1;
 274     char fn[PATH_MAX];
 275     int ret = -1;
 276     pid_t _pid;
 277
 278     if (!pid)
 279         pid = &_pid;
 280
 281     pa_runtime_path("pid", fn, sizeof(fn));
 282
 283     if ((fd = open_pid_file(fn, O_RDONLY)) < 0)
 284         goto fail;
 285
 286     if ((*pid = read_pid(fn, fd)) == (pid_t) -1)
 287         goto fail;
 288
 289     ret = kill(*pid, sig);
 290
 291 fail:
 292
 293     if (fd >= 0) {
 294         pa_lock_fd(fd, 0);
 295         pa_close(fd);
 296     }
 297
 298     return ret;
 299
 300 }
 301
 302 #else /* OS_IS_WIN32 */
 303
 304 int pa_pid_file_kill(int sig, pid_t *pid) {
 305     return -1;
 306 }
 307
 308 #endif