Patch: Improved Error Reporting when rotation log file/moving files

[Lars Michelsen]

Hi Ethan, Hi List,
I just had some problems with the log rotation of the nagios logfile
on my productive nagios system. After several trys to get the source
of the problem I recognized some permission problems. That was a hard
way to get to that point and fix this.
Finally this was only possible due to some modifications to the Nagios
code. True, I could turn on the debug mode, but that's no option on
the productive system.

Here is a small patch for a little better error reporting to the log
file when renaming files. This patch should help others to recognize
the source of their problem much faster.

Peronaly I would add much more error messages for the user to that
functions but that would also blow up the code.

This patch is for Nagios 2.10, but it should also be applicable to Nagios 3.0.

--- base/utils.c.orig   2007-10-24 17:37:06.000000000 +0200
+++ base/utils.c        2007-10-24 18:42:52.000000000 +0200
@@ -4329,6 +4329,7 @@
        int source_fd;
        int dest_fd;
        int bytes_read;
+       char temp_buffer[MAX_INPUT_BUFFER];


        /* make sure we have something */
@@ -4338,6 +4339,13 @@
        /* first see if we can rename file with standard function */
        rename_result=rename(source,dest);

+       /* the user should know why the logrotation fails */
+       if(rename_result==-1 && errno!=EXDEV) {
+               snprintf(temp_buffer,sizeof(temp_buffer),"ERROR in
my_rename: unhandled error '%s' while renaming from '%s' to
'%s'",strerror(errno),source,dest);
+               temp_buffer[sizeof(temp_buffer)-1]='\x0';
+               write_to_all_logs(temp_buffer,NSLOG_PROCESS_INFO);
+       }
+
        /* an error occurred because the source and dest files are on
different filesystems */
        if(rename_result==-1 && errno==EXDEV){


--
Lars

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