[4.2.0] Src/hist.c:lockhistfile() endless loop

[4.2.0] Src/hist.c:lockhistfile() endless loop

[KELEMEN Peter]

[ Please Cc: me since I'm not subscribed.  Thanks. ]

Hello,

  2141              while (link(tmpfile, lockfile) < 0) {
  2142                  if (stat(lockfile, &sb) < 0) {
  2143                      if (errno == ENOENT)
  2144                          continue;

This looks like an endless loop if
 1) link() fails, and
 2) stat() returns -ENOENT.

It was the case for me with $HOME being on OpenAFS and an expired
ticket (link() returned -EACCES).  What guarantees do we have here
to say that link() will eventually succeed?

Peter

-- 
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 Kelemen Péter     /       \       /       \     Peter.Kelemen@cern.ch
.+'         `+...+'         `+...+'         `+...+'         `+...+'

Re: [4.2.0] Src/hist.c:lockhistfile() endless loop

[Wayne Davison]

[-- Attachment #1: Type: text/plain, Size: 263 bytes --]

On Fri, May 07, 2004 at 12:35:15PM +0200, KELEMEN Peter wrote:
> This looks like an endless loop if
>  1) link() fails, and
>  2) stat() returns -ENOENT.

Seems to me that the attached change would avoid the infinite loop in
the failure case you cite.

..wayne..

[-- Attachment #2: lockfile.patch --]
[-- Type: text/plain, Size: 419 bytes --]

--- Src/hist.c	29 Oct 2003 19:17:30 -0000	1.47
+++ Src/hist.c	7 May 2004 15:39:44 -0000
@@ -2139,7 +2139,9 @@ lockhistfile(char *fn, int keep_trying)
 	    write(fd, tmpfile+len+1, strlen(tmpfile+len+1));
 	    close(fd);
 	    while (link(tmpfile, lockfile) < 0) {
-		if (stat(lockfile, &sb) < 0) {
+		if (errno != EEXIST)
+		    ;
+		else if (stat(lockfile, &sb) < 0) {
 		    if (errno == ENOENT)
 			continue;
 		}