[732] in Zephyr_Bugs
Overwriting zwgc's /tmp/wg.
daemon@ATHENA.MIT.EDU (R. Bernstein)
Fri Dec 15 17:55:05 1995
Date: Fri, 15 Dec 1995 17:54:43 -0500
From: "R. Bernstein" <rocky@drmsr011.drm.pwj.com>
To: bug-zephyr@MIT.EDU
Cc: murali@drmsr011.drm.pwj.com
Reply-To: rocky@drmsr011.drm.pwj.com
Problem:
If zwgc is run twice, the /tmp/wg.<uid> file gets overwritten. zwctl
(without a WGFILE set) will however only have an effect on one of
these.
If zwgc is running multiple times and one zwgc is killed, /tmp/wg.<uid>
file is deleted. This is bad in that it can mess up another working
version.
Suggested Solution:
Before overwriting /tmp/wg.<uid> check to see if the file is already
there. If so, indicate that this would be a problem were zwgc to
continue. And suggest deleting the /tmp/wg.<uid> file if it
is for a stale process. Then die.
More work could be done, such as to check to see if the process is
stale.
Diff:
The below works for AIX. In time I'll be trying on SunOS and Solaris.
*** zephyr.c.orig Fri Jul 7 18:00:53 1995
--- zephyr.c Fri Dec 15 17:27:45 1995
***************
*** 13,18 ****
--- 13,19 ----
*/
#include <sysdep.h>
+ #include <sys/stat.h>
#if (!defined(lint) && !defined(SABER))
static const char rcsid_zephyr_c[] = "zephyr.c,v 1.7 1995/07/07 22:00:53 ghudson Exp";
***************
*** 138,143 ****
--- 139,145 ----
char *temp;
char *exposure;
FILE *port_file;
+ struct stat *Buffer;
/*
* Initialize zephyr. If error, print error message & exit.
***************
*** 151,156 ****
--- 153,167 ----
*/
temp = get_zwgc_port_number_filename();
errno = 0;
+ if (stat(temp, Buffer) == 0) {
+ fprintf(stderr,
+ "zwgc: file %s already exists. You may have another zwgc running.\n",
+ temp);
+ fprintf(stderr,
+ "zctl may get confused. If zwgc is not running, remove %s.\n",
+ temp);
+ exit(1);
+ }
port_file = fopen(temp, "w+");
if (port_file) {
fprintf(port_file, "%d\n", port);
