From: Branden Robinson <[email protected]>
Update StorePid() function to use Matthieu Herrb's changes that refuse
to open an existing pid file, and take more care with the size of the
Pid_t type.
Matthieu Herrb rewrote the StorePid() function based on my changes; he
made it more careful with the size of Pid_t, and treats an existing pid
file as a failure. I then made some more changes: use _SysErrorMsg()
instead of strerror(), and don't assume that the process id we write to
the pidFile is 5 digits.
Forward-ported by David Nusinow, Eugene Konev and Julien Cristau.
---
dm.c | 95 +++++++++++++++++++++++++++++++++--------------------------------
1 files changed, 48 insertions(+), 47 deletions(-)
diff --git a/dm.c b/dm.c
index b60acc9..56c5fa8 100644
--- a/dm.c
+++ b/dm.c
@@ -106,7 +106,7 @@ static int TitleLen;
static SIGVAL ChildNotify (int n);
#endif
-static int StorePid (void);
+static long StorePid (void);
static void RemovePid (void);
static pid_t parent_pid = -1; /* PID of parent xdm process */
@@ -902,13 +902,20 @@ CloseOnFork (void)
static int pidFd;
static FILE *pidFilePtr;
-static int
+/*
+ * Create and populate file storing xdm's process ID.
+ */
+static long
StorePid (void)
{
- int oldpid;
+ long oldpid;
+ char pidstr[11]; /* enough space for a 32-bit pid plus \0 */
+ size_t pidstrlen;
- if (pidFile[0] != '\0') {
- pidFd = open (pidFile, O_RDWR);
+ if (pidFile[0] != '\0')
+ {
+ Debug ("storing process ID in %s\n", pidFile);
+ pidFd = open (pidFile, O_WRONLY|O_CREAT|O_EXCL, 0666);
if (pidFd == -1 && errno == ENOENT)
{
/* Make sure directory exists if needed
@@ -931,58 +938,52 @@ StorePid (void)
}
}
- pidFd = open (pidFile, O_RDWR|O_CREAT, 0666);
+ pidFd = open (pidFile, O_WRONLY|O_CREAT|O_EXCL, 0666);
}
- if (pidFd == -1 || !(pidFilePtr = fdopen (pidFd, "r+")))
+ if (pidFd == -1)
{
- LogError ("process-id file %s cannot be opened\n",
- pidFile);
- return -1;
- }
- if (fscanf (pidFilePtr, "%d\n", &oldpid) != 1)
- oldpid = -1;
- fseek (pidFilePtr, 0l, 0);
- if (lockPidFile)
- {
-#ifdef F_SETLK
-# ifndef SEEK_SET
-# define SEEK_SET 0
-# endif
- struct flock lock_data;
- lock_data.l_type = F_WRLCK;
- lock_data.l_whence = SEEK_SET;
- lock_data.l_start = lock_data.l_len = 0;
- if (fcntl(pidFd, F_SETLK, &lock_data) == -1)
+ if (errno == EEXIST)
{
- if (errno == EAGAIN)
- return oldpid;
- else
+ /* pidFile already exists; see if we can open it */
+ pidFilePtr = fopen (pidFile, "r");
+ if (pidFilePtr == NULL)
+ {
+ LogError ("cannot open process ID file %s for reading: "
+ "%s\n", pidFile, _SysErrorMsg (errno));
return -1;
+ }
+ if (fscanf (pidFilePtr, "%ld\n", &oldpid) != 1)
+ {
+ LogError ("existing process ID file %s empty or contains "
+ "garbage\n", pidFile);
+ oldpid = -1;
+ }
+ fclose (pidFilePtr);
+ return oldpid;
}
-#else
-# ifdef LOCK_EX
- if (flock (pidFd, LOCK_EX|LOCK_NB) == -1)
- {
- if (errno == EWOULDBLOCK)
- return oldpid;
else
- return -1;
- }
-# else
- if (lockf (pidFd, F_TLOCK, 0) == -1)
{
- if (errno == EACCES)
- return oldpid;
- else
- return -1;
+ LogError ("cannot fdopen process ID file %s for writing: "
+ "%s\n", pidFile, _SysErrorMsg (errno));
+ return -1;
}
-# endif
-#endif
}
- ftruncate(pidFd, 0);
- fprintf (pidFilePtr, "%5ld\n", (long)getpid ());
+ if ((pidFilePtr = fdopen (pidFd, "w")) == NULL)
+ {
+ LogError ("cannot open process ID file %s for writing: %s\n",
+ pidFile, _SysErrorMsg (errno));
+ return -1;
+ }
+ (void) snprintf (pidstr, 11, "%ld", (long) getpid ());
+ pidstrlen = strlen (pidstr);
+ if (fprintf (pidFilePtr, "%s\n", pidstr) != ( pidstrlen + 1))
+ {
+ LogError ("cannot write to process ID file %s: %s\n", pidFile,
+ _SysErrorMsg (errno));
+ return -1;
+ }
(void) fflush (pidFilePtr);
- RegisterCloseOnFork (pidFd);
+ (void) fclose (pidFilePtr);
}
return 0;
}
--
1.6.5.7
_______________________________________________
xorg-devel mailing list
[email protected]
http://lists.x.org/mailman/listinfo/xorg-devel
