1 files changed, 131 insertions, 0 deletions
diff --git a/lib/util/pidfile.c b/lib/util/pidfile.c
new file mode 100644
index 0000000000..ac8ff8a0c3
--- /dev/null
+++ b/lib/util/pidfile.c
@@ -0,0 +1,131 @@
+/* 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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "lib/util/pidfile.h"
+
+/**
+ * @file
+ * @brief Pid file handling
+ */
+
+/**
+ * return the pid in a pidfile. return 0 if the process (or pidfile)
+ * does not exist 
+ */
+pid_t pidfile_pid(const char *piddir, const char *name)
+{
+	int fd;
+	char pidstr[20];
+	pid_t ret;
+	char *pidFile;
+
+	if (asprintf(&pidFile, "%s/%s.pid", piddir, name) < 0) {
+		return 0;
+	}
+
+	fd = open(pidFile, O_NONBLOCK | O_RDONLY, 0644);
+
+	if (fd == -1) {
+		SAFE_FREE(pidFile);
+		return 0;
+	}
+
+	ZERO_STRUCT(pidstr);
+
+	if (read(fd, pidstr, sizeof(pidstr)-1) <= 0) {
+		goto noproc;
+	}
+
+	ret = (pid_t)atoi(pidstr);
+	if (ret <= 0) {
+		goto noproc;
+	}
+	
+	if (!process_exists_by_pid(ret)) {
+		goto noproc;
+	}
+
+	if (fcntl_lock(fd,F_SETLK,0,1,F_RDLCK)) {
+		/* we could get the lock - it can't be a Samba process */
+		goto noproc;
+	}
+
+	close(fd);
+	SAFE_FREE(pidFile);
+	return ret;
+
+ noproc:
+	close(fd);
+	unlink(pidFile);
+	SAFE_FREE(pidFile);
+	return 0;
+}
+
+/**
+ * create a pid file in the pid directory. open it and leave it locked 
+ */
+void pidfile_create(const char *piddir, const char *name)
+{
+	int     fd;
+	char    buf[20];
+	char *pidFile;
+	pid_t pid;
+
+	if (asprintf(&pidFile, "%s/%s.pid", piddir, name) < 0) {
+		DEBUG(0,("ERROR: Out of memory\n"));
+		exit(1);
+	}
+
+	pid = pidfile_pid(piddir, name);
+	if (pid != 0) {
+		DEBUG(0,("ERROR: %s is already running. File %s exists and process id %d is running.\n", 
+			 name, pidFile, (int)pid));
+		exit(1);
+	}
+
+	fd = open(pidFile, O_NONBLOCK | O_CREAT | O_WRONLY | O_EXCL, 0644);
+	if (fd == -1) {
+		DEBUG(0,("ERROR: can't open %s: Error was %s\n", pidFile, 
+			 strerror(errno)));
+		exit(1);
+	}
+
+	smb_set_close_on_exec(fd);
+
+	if (fcntl_lock(fd,F_SETLK,0,1,F_WRLCK)==false) {
+		DEBUG(0,("ERROR: %s : fcntl lock of file %s failed. Error was %s\n",  
+              name, pidFile, strerror(errno)));
+		exit(1);
+	}
+
+	memset(buf, 0, sizeof(buf));
+	slprintf(buf, sizeof(buf) - 1, "%u\n", (unsigned int) getpid());
+	if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf)) {
+		DEBUG(0,("ERROR: can't write to file %s: %s\n", 
+			 pidFile, strerror(errno)));
+		exit(1);
+	}
+
+	/* Leave pid file open & locked for the duration... */
+	SAFE_FREE(pidFile);
+}