Re: [PATCH] pagealign_alloc: don't loop endlessly

[Derek Price]

I've attached a revised version of my earlier patch that preserves more
information and avoids problems when the exit handlers call error()
after error() calls exit().

Regards,

Derek

Index: src/ChangeLog
===================================================================
RCS file: /cvs/ccvs/src/ChangeLog,v
retrieving revision 1.3186
diff -u -p -r1.3186 ChangeLog
--- src/ChangeLog       4 May 2005 02:48:16 -0000       1.3186
+++ src/ChangeLog       4 May 2005 20:14:40 -0000
@@ -1,3 +1,7 @@
+2005-05-04  Derek Price  <derek@ximbiot.com>
+
+       * error.c (error): Avoid recursion and syslog the problem.
+
 2005-05-03  Derek Price  <derek@ximbiot.com>

        * tag.c (is_in_val_tags): Remove unnecessary existance checking for the
Index: src/error.c
===================================================================
RCS file: /cvs/ccvs/src/error.c,v
retrieving revision 1.42
diff -u -p -r1.42 error.c
--- src/error.c 18 Mar 2005 16:41:24 -0000      1.42
+++ src/error.c 4 May 2005 20:14:40 -0000
@@ -120,16 +120,26 @@ error (int status, int errnum, const cha
     char *cmdbuf;
     char *emptybuf = "";

+    static const char *last_message = NULL;
+    static va_list last_args;
+    static int last_status;
+    static int last_errnum;
+
+    if (last_message) goto recursion_error;
+    last_message = message;
+    va_start (args, message);
+    last_args = args;
+    last_status = status;
+    last_errnum = errnum;
+
     /* Initialize these to avoid a lot of special case error handling.  */
     buf = statbuf;
     buf2 = statbuf2;
     cmdbuf = emptybuf;

     /* Expand the message the user passed us.  */
-    va_start (args, message);
     length = sizeof (statbuf);
     buf = vasnprintf (statbuf, &length, message, args);
-    va_end (args);
     if (!buf) goto memerror;

     /* Expand the cvs commmand name to <cmd> or [<cmd> aborted].
@@ -161,6 +171,12 @@ error (int status, int errnum, const cha
     /* Send the final message to the client or log it.  */
     cvs_outerr (buf2, length);

+    /* Reset our recursion lock.  This needs to be done before the call to
+     * exit() to allow the exit handlers to make calls to error().
+     */
+    last_message = NULL;
+    va_end (args);
+
     /* Done, if we're exiting.  */
     if (status)
        exit (EXIT_FAILURE);
@@ -194,6 +210,37 @@ memerror:
     syslog (LOG_DAEMON | LOG_EMERG, "Memory exhausted.  Aborting.");
 #endif /* HAVE_SYSLOG_H */

+    goto sidestep_done;
+
+recursion_error:
+#if HAVE_SYSLOG_H
+    /* Syslog the problem since recursion probably means that we encountered an
+     * error while attempting to send the last error message to the client.
+     */
+
+    syslog (LOG_DAEMON | LOG_EMERG,
+           "error (%d, %d) called recursively.  Original message was:",
+           last_status, last_errnum);
+    vsyslog (LOG_DAEMON | LOG_EMERG, last_message, last_args);
+
+
+    syslog (LOG_DAEMON | LOG_EMERG,
+            "error (%d, %d) called recursively.  Second message was:",
+           status, errnum);
+    va_start (args, message);
+    vsyslog (LOG_DAEMON | LOG_EMERG, message, args);
+    va_end (args);
+
+    syslog (LOG_DAEMON | LOG_EMERG, "Aborting.");
+#endif /* HAVE_SYSLOG_H */
+
+sidestep_done:
+    /* Reset our recursion lock.  This needs to be done before the call to
+     * exit() to allow the exit handlers to make calls to error().
+     */
+    last_message = NULL;
+    va_end (last_args);
+
     exit (EXIT_FAILURE);
 }

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