Re: [Sshguard-users] assert(ret != 0) in read_from() in sshguard_logsuck.c keeps failing in 1.5rc3

[Mij <mi...@ss...>]

Very curious, I noticed the same possibility some weeks ago, and thought "that condition for
strings of logs length must be so rare that it's more likely for me to introduce a bug in the code
for handling it" -- and just threw the assert() in there. Noot! :)

Now committed a version for handling it as r204, thanks!


On Jul 8, 2010, at 14:46 , Colin Keith wrote:

> Hi,
> 
> I keep having intermittent problems with the assert in this code from
> sshguard-1.5rc3/src/sshguard_logsuck.c
> 
> 351     /* read until error, newline reached, or buffer exhausted */
> 352     i = 0;
> 353     do {
> 354         ret = read(fd, & buf[i++], 1);
> 355     } while (ret == 1 && buf[i-1] != '\n' && i < buflen-2);
> 356     assert(ret != 0);
> 357     buf[i] = '\0';
> 
> I keep getting the error message;
> 
> Assertion `ret != 0' failed.
> 
> I added some code to print the various values that are used:
> 
> if(ret == 0) {
>   sshguard_log(LOG_NOTICE, "ret = %d, i = %d, buflen = %d, buf[i-1] =
> '%c', buf = %s\n", ret, i, (int)buflen, buf[i-1], buf);
> }
> 
> and from that received this output;
> 
> ret = 0, i = 62, buflen = 999, buf[i-1] = 'n', buf = ul 07 16:45:26
> thor.hagenhosting.com proftpd[18688] thor.hagenhosting.com
> (61.55.146.28[61.55.146.28]): FTP session closed.
> 
> 
> Why is ret == 0 bad? Doesn't that just me EOF?
> 
> I'm reading from /var/log/ftp.log which is written to by syslog (it is
> just easier that way) so isn't this just saying that syslog hadn't
> finished writing the entire line to the log file while I was reading
> it and thus hit the EOF before the EOL?
> 
> This is really annoying because when it happens sshguard falls over
> and so leaves the box open to annoyances again.
> 
> Thanks,
> Colin.
> 
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