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(lock_superlock): Delete superlock file if it stayed

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locked for 20 seconds.
This commit is contained in:
Richard M. Stallman 1996-09-12 17:29:17 +00:00
parent 9614b740ac
commit a1faca2631
1 changed files with 43 additions and 11 deletions
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54
src/filelock.c
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@ -353,32 +353,64 @@ lock_superlock (lfname)
{
register int i, fd;
DIR *lockdir;
struct stat first_stat, last_stat;
for (i = -20; i < 0 && (fd = open (superlock_file,
O_WRONLY | O_EXCL | O_CREAT, 0666)) < 0;
for (i = -20; i < 0;
i++)
{
fd = open (superlock_file,
O_WRONLY | O_EXCL | O_CREAT, 0666);
/* If we succeeded in creating the superlock, we win.
Fill in our info and return. */
if (fd >= 0)
{
#ifdef USG
chmod (superlock_file, 0666);
#else
fchmod (fd, 0666);
#endif
write (fd, lfname, strlen (lfname));
close (fd);
return;
}
/* If the problem is not just that it is already locked,
give up. */
if (errno != EEXIST)
return;
message ("Superlock file exists, retrying...");
if (i == -20)
stat (superlock_file, &first_stat);
if (i == -1)
stat (superlock_file, &last_stat);
/* This seems to be necessary to prevent Emacs from hanging when the
competing process has already deleted the superlock, but it's still
in the NFS cache. So we force NFS to synchronize the cache. */
if (lockdir = opendir (lock_dir))
lockdir = opendir (lock_dir);
if (lockdir)
closedir (lockdir);
sleep (1);
}
if (fd >= 0)
if (first_stat.st_ctime == last_stat.st_ctime)
{
#ifdef USG
chmod (superlock_file, 0666);
#else
fchmod (fd, 0666);
#endif
write (fd, lfname, strlen (lfname));
close (fd);
int value;
value = unlink (superlock_file);
if (value != -1)
message ("Superlock file deleted");
else
message ("Failed to delete superlock file");
}
else
message ("Giving up on the superlock file");
}
void