I have Apache 1.3.12 installed on Solaris 2.7 running with
mod_perl 1.24. I have a simple mod_perl script, it actually
uses Apache::Registry, that uses a Perl module called RRDs
that can generate images/graphs from a round robin
database. If you pass it a '-' as a file name rrd_graph.c
prints to 'stdout', or file descriptor 1. Everything works
just fine if I run the script using mod_cgi as the handler.
But when using mod_perl I get a 200 response from the server
but no data sent to the socket the request came in on.
I just install Perl 5.6 with sfio (safe and fast I/O).
There was no difference in the way the script was handled.
I did see something interesting in the output of truss when
running it on the pid of httpd -X and requesting the script
that generates a Content-type: image/gif header followed by
the raw gif file.
This is edited for brevity:
# A socket is created using file descriptor #3
getsockname(3, 0xFFBEF860, 0xFFBEF874, 1) = 0
setsockopt(3, 6, 1, 0xFFBEF7C4, 4, 1) = 0
alarm(300) = 0
# Here is the HTTP GET request on the socket using fd #3
read(3, " G E T / p e r l / i m".., 4096) = 362
# Now the script that was requested gets opened on file
descriptor #4
stat64("/usr/local/mod_perl/image_out.cgi", 0x003AECD8) = 0
open64("/usr/local/mod_perl/image_out.cgi", O_RDONLY) = 4
fstat64(4, 0xFFBED058) = 0
ioctl(4, TCGETA, 0xFFBECFE4) Err#25
ENOTTY
read(4, " # ! / u s r / l o c a l".., 8192) = 3815
read(4, 0x007E400C, 8192) = 0
llseek(4, 0, SEEK_CUR) = 3815
close(4) = 0
# Apache sends the status code 200 indicating success
write(3, " H T T P / 1 . 1 2 0 0".., 186) = 186
# The RRD file gets opened on file descriptor #4
open("/usr/local/router/data/some_router/srp000.rrd",
O_RDONLY) = 4
read(4, " R R D\0 0 0 0 1\0\0\0\0".., 8192) = 8192
llseek(4, 0, SEEK_CUR) = 8192
lseek(4, 8428, SEEK_SET) = 8428
read(4, "7FFFFFFFFFFFFFFF7FFFFFFF".., 8192) = 8192
lseek(4, 2796, SEEK_SET) = 2796
read(4, "7FFFFFFFFFFFFFFF7FFFFFFF".., 8192) = 8192
llseek(4, 0xFFFFFFFFFFFFF600, SEEK_CUR) = 8428
close(4) = 0
# Now the interesting part; Instead of writing the image
to the socket (file
descriptor #4)
# it writes to stdout or file descriptor #1
ioctl(1, TCGETA, 0xFFBEE4EC) = 0
write(1, " G I F 8 7 aB7021001B3\0".., 1024) = 1024
write(1, "\f rD2 j /CE zF3EE ?188A".., 441) = 441
# Apache writes to the access_log
write(19, " 10.0.0.1".., 148) = 148
# Now the child process blocks on accept waiting for
another request
accept(16, 0xFFBEF850, 0xFFBEF874, 1) (sleeping...)
Well now with all that said, I still don't know why it is
not printing to the
socket or file descriptor #4. Any ideas?
