[pisa-src] r1819 - in trunk: libpisa/util.c libpisa/util.h pisacd/cdmain.c pisasd/sdmain.c
- From: Thomas Jansen <mithi@xxxxxxxxx>
- To: pisa-src@xxxxxxxxxxxxx
- Date: Thu, 26 Nov 2009 16:21:48 +0100
Author: tjansen
Date: Thu Nov 26 16:21:48 2009
New Revision: 1819
Log:
Rewrote pisa_create_lock_file().
This gets rid of PISA_IFEL in util.c. Also, the killold option has been removed.
Modified:
trunk/libpisa/util.c
trunk/libpisa/util.h
trunk/pisacd/cdmain.c
trunk/pisasd/sdmain.c
Modified: trunk/libpisa/util.c
==============================================================================
--- trunk/libpisa/util.c Thu Nov 26 16:14:45 2009 (r1818)
+++ trunk/libpisa/util.c Thu Nov 26 16:21:48 2009 (r1819)
@@ -246,93 +246,48 @@
return err;
}
+/**
+ * Remove the lock file.
+ *
+ * @param filename filename for the lock file
+ * @return 0 on success, -1 otherwise
+ */
int pisa_remove_lock_file(const char *filename)
{
return unlink(filename);
}
-int pisa_create_lock_file(const char *filename, int killold)
+/**
+ * Create and lock a lock file to prevent multiple daemons from running.
+ * If we're a new process trying to get hold of an already existing lock we
+ * exit. If we're the only process, we print our process id to the lock file.
+ *
+ * Note that we don't close fd to keep the lock intact. Since we use lockf and
+ * not file existence for the decision, lingering files do not prevent us
+ * from running if their old process lost their lock (i.e. died).
+ *
+ * @param filename filename for the lock file
+ */
+void pisa_create_lock_file(const char *filename)
{
- int err = 0, fd = 0, old_pid = 0, new_pid_str_len = 0;
- char old_pid_str[64], new_pid_str[64];
+ char pid_str[8];
+ int fd, pid;
- memset(old_pid_str, 0, sizeof(old_pid_str));
- memset(new_pid_str, 0, sizeof(new_pid_str));
-
- /* New pid */
- snprintf(new_pid_str, sizeof(new_pid_str)-1, "%d\n", getpid());
- new_pid_str_len = strlen(new_pid_str);
- PISA_IFEL((new_pid_str_len <= 0), -1, "pID length error.\n");
-
- /* Read old pid */
- fd = open(filename, O_RDWR | O_CREAT, 0644);
- PISA_IFEL((fd <= 0), -1, "opening lock file failed\n");
-
- if (read(fd, old_pid_str, sizeof(old_pid_str) - 1) < 0) {
- PISA_ERROR("Cannot read data from fd[%d] (%s)\n",
- fd, strerror(errno));
- err = errno;
- goto out_err;
- }
- old_pid = atoi(old_pid_str);
-
- // TODO we should exit in this case, if the kill switch is not set
-
- if (lockf(fd, F_TLOCK, 0) < 0)
- {
- PISA_IFEL(!killold, -12,
- "PISA daemon already running with pid %d\n", old_pid);
-
- PISA_INFO("\nPISA daemon already running with pid %d\n"
- "-k option given, terminating old one...\n", old_pid);
- /* Erase the old lock file to avoid having multiple pids
- in the file */
- if (lockf(fd, F_ULOCK, 0) < 0) {
- PISA_ERROR("Cannot acquire a lock on fd[%d] (%s)\n",
- fd, strerror(errno));
- err = errno;
- goto out_err;
- }
- close(fd);
- PISA_IFEL(pisa_remove_lock_file(filename), -1,
- "Removing lock file failed.\n");
-
- /* fd = open(filename, O_RDWR | O_CREAT, 0644); */
- fd = open(filename, O_RDWR | O_CREAT | O_TRUNC, 0644);
-
- /* Don't close file descriptor because new started process is
- running. */
- PISA_IFEL((fd <= 0), -1, "Opening lock file failed.\n");
- PISA_IFEL(lockf(fd, F_TLOCK, 0), -1, "Lock attempt failed.\n");
-
- err = kill(old_pid, SIGKILL);
- if (err != 0) {
- PISA_ERROR("\nError when trying to send signal SIGKILL
"\
- "process identified by process identifier "\
- "%d.\n", old_pid);
- PISA_PERROR("errno after kill() is: ");
- }
- }
- /* else if (killold)
- {
- lseek(fd,0,SEEK_SET);
- write(fd, new_pid_str, new_pid_str_len);
- system("NEW_PID=$(sudo awk NR==1 /var/lock/hipd.lock)");
- system("OLD_PID=$(/bin/pidof -o $NEW_PID hipd)");
- system("kill -9 $OLD_PID");
- } */
-
- lseek(fd, 0, SEEK_SET);
-
- PISA_IFEL((write(fd, new_pid_str, new_pid_str_len) != new_pid_str_len),
- -1, "Writing new process identifier failed.\n");
+ if (!(fd = open(filename, O_RDWR | O_CREAT, 0644))) {
+ PISA_ERROR("Can't open lock file.");
+ exit(1);
+ }
- out_err:
- if (err == -12) {
- exit(0);
+ if (lockf(fd, F_TLOCK, 0) < 0) {
+ memset(pid_str, 0, sizeof(pid_str));
+ read(fd, pid_str, sizeof(pid_str) - 1);
+ pid = atoi(pid_str);
+ PISA_ERROR("Another process is already running: PID %i.\n",
pid);
+ exit(2);
}
- return err;
+ snprintf(pid_str, sizeof(pid_str), "%d\n", getpid());
+ write(fd, pid_str, strlen(pid_str));
}
/**
Modified: trunk/libpisa/util.h
==============================================================================
--- trunk/libpisa/util.h Thu Nov 26 16:14:45 2009 (r1818)
+++ trunk/libpisa/util.h Thu Nov 26 16:21:48 2009 (r1819)
@@ -55,7 +55,7 @@
bool pisa_check_if_hipd_runs(void);
-int pisa_create_lock_file(const char *filename, const int killold);
+void pisa_create_lock_file(const char *filename);
int pisa_remove_lock_file(const char *filename);
int pisa_read_nameserver(struct in_addr *dnsaddr, const char *resolvconf);
Modified: trunk/pisacd/cdmain.c
==============================================================================
--- trunk/pisacd/cdmain.c Thu Nov 26 16:14:45 2009 (r1818)
+++ trunk/pisacd/cdmain.c Thu Nov 26 16:21:48 2009 (r1819)
@@ -302,7 +302,7 @@
cd_get_cmdargs(argc, argv);
/* Check and create lockfile */
- pisa_create_lock_file(PISACD_LOCK_FILE, cd_ctx.flag_kill_running);
+ pisa_create_lock_file(PISACD_LOCK_FILE);
/* Check, whether hipd is running. This is a requirement for
* using pisacd. The output will be written to stderr before
Modified: trunk/pisasd/sdmain.c
==============================================================================
--- trunk/pisasd/sdmain.c Thu Nov 26 16:14:45 2009 (r1818)
+++ trunk/pisasd/sdmain.c Thu Nov 26 16:21:48 2009 (r1819)
@@ -330,7 +330,7 @@
sd_get_cmdargs(argc, argv);
/* Check and create lockfile */
- pisa_create_lock_file(PISASD_LOCK_FILE, sd_ctx.flag_kill_running);
+ pisa_create_lock_file(PISASD_LOCK_FILE);
/* Check, whether hipd is running. This is a requirement for
* using pisasd. The output will be written to stderr before
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