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Diffstat (limited to 'Src/hist.c')
-rw-r--r--Src/hist.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/Src/hist.c b/Src/hist.c
index 86b08bd45..b1e4e82c4 100644
--- a/Src/hist.c
+++ b/Src/hist.c
@@ -2600,11 +2600,38 @@ lockhistfile(char *fn, int keep_trying)
int fd;
char *lockfile;
#ifdef HAVE_LINK
+# ifdef HAVE_SYMLINK
+ char pidbuf[32], *lnk;
+# else
char *tmpfile;
+# endif
#endif
lockfile = bicat(unmeta(fn), ".LOCK");
+ /* NOTE: only use symlink locking on a link()-having host in order to
+ * avoid a change from open()-based locking to symlink()-based. */
#ifdef HAVE_LINK
+# ifdef HAVE_SYMLINK
+ sprintf(pidbuf, "/pid-%ld/host-", (long)mypid);
+ lnk = bicat(pidbuf, getsparam("HOST"));
+ /* We'll abuse fd as our success flag. */
+ while ((fd = symlink(lnk, lockfile)) < 0) {
+ if (errno != EEXIST || !keep_trying)
+ break;
+ if (lstat(lockfile, &sb) < 0) {
+ if (errno == ENOENT)
+ continue;
+ break;
+ }
+ if (time(NULL) - sb.st_mtime < 10)
+ sleep(1);
+ else
+ unlink(lockfile);
+ }
+ if (fd < 0)
+ lockhistct--;
+ free(lnk);
+# else /* not HAVE_SYMLINK */
if ((fd = gettempfile(fn, 0, &tmpfile)) >= 0) {
FILE *out = fdopen(fd, "w");
if (out) {
@@ -2618,7 +2645,7 @@ lockhistfile(char *fn, int keep_trying)
lockfile, errno);
else if (!keep_trying)
;
- else if (stat(lockfile, &sb) < 0) {
+ else if (lstat(lockfile, &sb) < 0) {
if (errno == ENOENT)
continue;
zerr("failed to stat lock file %s: %e", lockfile, errno);
@@ -2635,11 +2662,12 @@ lockhistfile(char *fn, int keep_trying)
unlink(tmpfile);
free(tmpfile);
}
+# endif /* not HAVE_SYMLINK */
#else /* not HAVE_LINK */
while ((fd = open(lockfile, O_WRONLY|O_CREAT|O_EXCL, 0644)) < 0) {
if (errno != EEXIST || !keep_trying)
break;
- if (stat(lockfile, &sb) < 0) {
+ if (lstat(lockfile, &sb) < 0) {
if (errno == ENOENT)
continue;
break;