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/* pidfile handling for DBMail, many thanks to Tridge and Samba
* for making their software available under the GNU GPL.
*
* Modified for DBMail by Aaron Stone, July 9, 2004.
*/
/* this code is broken - there is a race condition with the unlink (tridge) */
/*
Unix SMB/CIFS implementation.
pidfile handling
Copyright (C) Andrew Tridgell 1998
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "dbmail.h"
#define THIS_MODULE "pidfile"
/* These are used by pidfile_remove. */
static FILE *pidfile_to_close;
static char *pidfile_to_remove;
/* Check if a process exists. */
static int process_exists(pid_t pid)
{
if (pid > 0)
return (kill(pid, 0) == 0 || errno != ESRCH);
return 0;
}
/* Return the pid in a pidfile, or return 0
* if the process or pidfile does not exist. */
static pid_t pidfile_pid(const char *pidFile)
{
FILE *f;
char pidstr[20];
unsigned ret;
memset(pidstr, 0, sizeof(pidstr));
if (!(f = fopen(pidFile, "r"))) {
return 0;
}
if (fread(pidstr, sizeof(char), sizeof(pidstr)-1, f) <= 0) {
goto noproc;
}
ret = atoi(pidstr);
if (!process_exists((pid_t)ret)) {
goto noproc;
}
fclose(f);
return (pid_t)ret;
noproc:
fclose(f);
unlink(pidFile);
return 0;
}
static void pidfile_remove(void)
{
int res;
if (pidfile_to_close) {
res = fclose(pidfile_to_close);
if (res) TRACE(TRACE_ERR, "Error closing pidfile: [%s].",
strerror(errno));
pidfile_to_close = NULL;
}
if (pidfile_to_remove) {
res = unlink(pidfile_to_remove);
if (res) TRACE(TRACE_ERR, "Error unlinking pidfile [%s]: [%s].",
pidfile_to_remove, strerror(errno));
g_free(pidfile_to_remove);
pidfile_to_remove = NULL;
}
}
/* Create a pidfile and leave it open. */
void pidfile_create(const char *pidFile, pid_t pid)
{
FILE *f;
pid_t oldpid;
oldpid = pidfile_pid(pidFile);
if (oldpid != 0) {
TRACE(TRACE_EMERG, "File [%s] exists and process id [%d] is running.",
pidFile, (int)pid);
}
if (!(f = fopen(pidFile, "w"))) {
TRACE(TRACE_EMERG, "Cannot open pidfile [%s], error was [%s]",
pidFile, strerror(errno));
}
chmod(pidFile, 0644);
fprintf(f, "%u\n", pid);
fflush(f);
/* Leave pid file open & locked for the duration,
* but close and remove it upon termination. */
atexit(pidfile_remove);
pidfile_to_close = f;
pidfile_to_remove = g_strdup(pidFile);
}
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