| Subject: | infinite loop in http_write |
Hi all!
Here is a probleme I ran into recently, along with a patch that should fix it.
I had an application using HTTP::Lite v2.1.6 suddenly lock up and use 100% CPU (running on RedHat FC1, perl 5.8.3).
Checking the process with strace yields the following (see below).
Line 622 is in the while-loop at the end of the http_write method. Obviously, errors in the syswrite call are not beeing checked, causing an infinite loop here.
I've added a patch below that should fix the problem.
Best regards,
Florian Kirchmeir
strace output:
--- SIGPIPE (Broken pipe) @ 0 (0) ---
write(2, "Use of uninitialized value in addition (+) at /home/sam/sam/lib/HTTP/Lite.pm line 622.\n", 87) = 87
write(4, "User-Agent: HTTP::Lite/2.1.6\r\n", 30) = -1 EPIPE (Broken pipe)
--- SIGPIPE (Broken pipe) @ 0 (0) ---
write(2, "Use of uninitialized value in addition (+) at /home/sam/sam/lib/HTTP/Lite.pm line 622.\n", 87) = 87
write(4, "User-Agent: HTTP::Lite/2.1.6\r\n", 30) = -1 EPIPE (Broken pipe)
--- SIGPIPE (Broken pipe) @ 0 (0) ---
write(2, "Use of uninitialized value in addition (+) at /home/sam/sam/lib/HTTP/Lite.pm line 622.\n", 87) = 87
write(4, "User-Agent: HTTP::Lite/2.1.6\r\n", 30) = -1 EPIPE (Broken pipe)
--- SIGPIPE (Broken pipe) @ 0 (0) ---
write(2, "Use of uninitialized value in addition (+) at /home/sam/sam/lib/HTTP/Lite.pm line 622.\n", 87) = 87
write(4, "User-Agent: HTTP::Lite/2.1.6\r\n", 30) = -1 EPIPE (Broken pipe)
...
Patch:
Index: lib/HTTP/Lite.pm
===================================================================
RCS file: /home/sam/cvs/sam/lib/HTTP/Lite.pm,v
retrieving revision 1.1
retrieving revision 1.2
diff -r1.1 -r1.2
620a621
Show quoted text
> die $! unless(defined $bytes || $!{EAGAIN}); # non-recoverable error occured!
622c623,625
< $bytes += syswrite($fh, $line, length($line)-$bytes, $bytes ); # also here
---
Show quoted text> my $moreBytes = syswrite($fh, $line, length($line)-$bytes, $bytes ); # also here
> die $! unless(defined $moreBytes || $!{EAGAIN}); # non-recoverable error occured!
> $bytes += $moreBytes;