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author | Rainer Gerhards <rgerhards@adiscon.com> | 2008-04-16 15:27:53 +0200 |
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committer | Rainer Gerhards <rgerhards@adiscon.com> | 2008-04-16 15:27:53 +0200 |
commit | d9b0c77d3e719d4c08361e62f3b067228c30f6a9 (patch) | |
tree | 20318332f281d64c74d6b0767a24c996a3737901 /tools/pidfile.c | |
parent | 91661455ebf63275a849dc5c7f49c21d7837b442 (diff) | |
download | rsyslog-d9b0c77d3e719d4c08361e62f3b067228c30f6a9.tar.gz rsyslog-d9b0c77d3e719d4c08361e62f3b067228c30f6a9.tar.xz rsyslog-d9b0c77d3e719d4c08361e62f3b067228c30f6a9.zip |
some more cleanup
reduced dependencies, moved non-runtime files to its own directory except
for some whom's status is unclear
Diffstat (limited to 'tools/pidfile.c')
-rw-r--r-- | tools/pidfile.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/tools/pidfile.c b/tools/pidfile.c new file mode 100644 index 00000000..2be13da6 --- /dev/null +++ b/tools/pidfile.c @@ -0,0 +1,156 @@ +/* + pidfile.c - interact with pidfiles + Copyright (c) 1995 Martin Schulze <Martin.Schulze@Linux.DE> + + * This file is part of rsyslog. + * + * Rsyslog 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 3 of the License, or + * (at your option) any later version. + * + * Rsyslog 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 Rsyslog. If not, see <http://www.gnu.org/licenses/>. + * + * A copy of the GPL can be found in the file "COPYING" in this distribution. +*/ +#include "config.h" + + +#include "rsyslog.h" + +/* + * Sat Aug 19 13:24:33 MET DST 1995: Martin Schulze + * First version (v0.2) released + */ + +#include <stdio.h> +#include <unistd.h> +#include <sys/stat.h> +#include <sys/file.h> +#include <string.h> +#include <errno.h> +#include <signal.h> +#ifdef __sun +#include <fcntl.h> +#endif + +#include "srUtils.h" + +/* read_pid + * + * Reads the specified pidfile and returns the read pid. + * 0 is returned if either there's no pidfile, it's empty + * or no pid can be read. + */ +int read_pid (char *pidfile) +{ + FILE *f; + int pid; + + if (!(f=fopen(pidfile,"r"))) + return 0; + fscanf(f,"%d", &pid); + fclose(f); + return pid; +} + +/* check_pid + * + * Reads the pid using read_pid and looks up the pid in the process + * table (using /proc) to determine if the process already exists. If + * so 1 is returned, otherwise 0. + */ +int check_pid (char *pidfile) +{ + int pid = read_pid(pidfile); + + /* Amazing ! _I_ am already holding the pid file... */ + if ((!pid) || (pid == getpid ())) + return 0; + + /* + * The 'standard' method of doing this is to try and do a 'fake' kill + * of the process. If an ESRCH error is returned the process cannot + * be found -- GW + */ + /* But... errno is usually changed only on error.. */ + if (kill(pid, 0) && errno == ESRCH) + return(0); + + return pid; +} + +/* write_pid + * + * Writes the pid to the specified file. If that fails 0 is + * returned, otherwise the pid. + */ +int write_pid (char *pidfile) +{ + FILE *f; + int fd; + int pid; + + if ( ((fd = open(pidfile, O_RDWR|O_CREAT, 0644)) == -1) + || ((f = fdopen(fd, "r+")) == NULL) ) { + fprintf(stderr, "Can't open or create %s.\n", pidfile); + return 0; + } + + /* It seems to be acceptable that we do not lock the pid file + * if we run under Solaris. In any case, it is highly unlikely + * that two instances try to access this file. And flock is really + * causing me grief on my initial steps on Solaris. Some time later, + * we might re-enable it (or use some alternate method). + * 2006-02-16 rgerhards + */ + +#if HAVE_FLOCK + if (flock(fd, LOCK_EX|LOCK_NB) == -1) { + fscanf(f, "%d", &pid); + fclose(f); + printf("Can't lock, lock is held by pid %d.\n", pid); + return 0; + } +#endif + + pid = getpid(); + if (!fprintf(f,"%d\n", pid)) { + char errStr[1024]; + rs_strerror_r(errno, errStr, sizeof(errStr)); + printf("Can't write pid , %s.\n", errStr); + close(fd); + return 0; + } + fflush(f); + +#if HAVE_FLOCK + if (flock(fd, LOCK_UN) == -1) { + char errStr[1024]; + rs_strerror_r(errno, errStr, sizeof(errStr)); + printf("Can't unlock pidfile %s, %s.\n", pidfile, errStr); + close(fd); + return 0; + } +#endif + close(fd); + + return pid; +} + +/* remove_pid + * + * Remove the the specified file. The result from unlink(2) + * is returned + */ +int remove_pid (char *pidfile) +{ + return unlink (pidfile); +} + |