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authorRainer Gerhards <rgerhards@adiscon.com>2008-04-16 15:27:53 +0200
committerRainer Gerhards <rgerhards@adiscon.com>2008-04-16 15:27:53 +0200
commitd9b0c77d3e719d4c08361e62f3b067228c30f6a9 (patch)
tree20318332f281d64c74d6b0767a24c996a3737901 /tools/pidfile.c
parent91661455ebf63275a849dc5c7f49c21d7837b442 (diff)
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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.c156
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);
+}
+