1. Problem Description:
Hiya,
After querying a mod_perl run CGI, the corresponding apache2
process ends up having its fd 0 and/or fd 1 closed. This then
causes some other CGIs (for instance mod_python's viewvc) to
fail because they are not robust enough to cope with a closed
fd 0.
Stracing the apache2 process, here is what I observe:
[...]
4760 dup(0) = 17
4760 ioctl(17, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbfa94938) = -1 ENOTTY
(Inappropriate ioctl for device)
4760 _llseek(17, 0, [0], SEEK_CUR) = 0
4760 fstat64(17, {st_dev=makedev(0, 14), st_ino=1673, st_mode=S_IFCHR|0666,
st_nlink=1, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0,
st_rdev=makedev(1, 3), st_atime=2007/02/20-09:50:23,
st_mtime=2007/02/20-09:50:23, st_ctime=2007/02/20-09:50:23}) = 0
4760 fcntl64(17, F_SETFD, FD_CLOEXEC) = 0
4760 close(0) = 0
4760 dup(1) = 0
4760 ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbfa94938) = -1 ENOTTY
(Inappropriate ioctl for device)
4760 _llseek(0, 0, [0], SEEK_CUR) = 0
4760 fstat64(0, {st_dev=makedev(0, 14), st_ino=1673, st_mode=S_IFCHR|0666,
st_nlink=1, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0,
st_rdev=makedev(1, 3), st_atime=2007/02/20-09:50:23,
st_mtime=2007/02/20-09:50:23, st_ctime=2007/02/20-09:50:23}) = 0
4760 fcntl64(0, F_SETFD, 0) = 0
4760 ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbfa94918) = -1 ENOTTY
(Inappropriate ioctl for device)
4760 _llseek(0, 0, [0], SEEK_CUR) = 0
4760 close(1) = 0
[...]
And in the end:
[...]
4760 close(18) = 0
4760 close(1) = 0
4760 chdir("/etc/apache2") = 0
4760 dup(17) = 1
4760 ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbfa94938) = -1 ENOTTY
(Inappropriate ioctl for device)
4760 _llseek(1, 0, [0], SEEK_CUR) = 0
4760 fstat64(1, {st_dev=makedev(0, 14), st_ino=1673, st_mode=S_IFCHR|0666,
st_nlink=1, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0,
st_rdev=makedev(1, 3), st_atime=2007/02/20-09:50:23,
st_mtime=2007/02/20-09:50:23, st_ctime=2007/02/20-09:50:23}) = 0
4760 fcntl64(1, F_SETFD, 0) = 0
4760 close(17) = 0
4760 dup(0) = 17
4760 ioctl(17, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbfa94938) = -1 ENOTTY
(Inappropriate ioctl for device)
4760 _llseek(17, 0, [0], SEEK_CUR) = 0
4760 fstat64(17, {st_dev=makedev(0, 14), st_ino=1673, st_mode=S_IFCHR|0666,
st_nlink=1, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=0,
st_rdev=makedev(1, 3), st_atime=2007/02/20-09:50:23,
st_mtime=2007/02/20-09:50:23, st_ctime=2007/02/20-09:50:23}) = 0
4760 fcntl64(17, F_SETFD, FD_CLOEXEC) = 0
4760 ioctl(17, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbfa94918) = -1 ENOTTY
(Inappropriate ioctl for device)
4760 _llseek(17, 0, [0], SEEK_CUR) = 0
4760 close(0) = 0
4760 writev(16, [{"10\r\n", 4}, {"\n</body>\n</html>", 16}, {"\r\n", 2},
{"0\r\n\r\n", 5}], 4) = 27
4760 read(16, 0x84a69c0, 8000) = -1 EAGAIN (Resource temporarily
unavailable)
4760 write(9, "10.95.129.198 - - [28/Mar/2007:1"..., 2220) = 2220
4760 poll( <unfinished ...>
As you can see mod_perl saves the fd 0 with a dup, and then
closes it. It does the same for fd 1 but as 0 is now an
available fd, fd 1 ends up being dupped to fd 0. Things are then
messed up when mod_perl restores the fds in the end.
This is using debian's unstable apache 2.2.3, using the prefork
MPM.
I get the same behavior with either of the debian mod_perl
package (2.0.2) or 2.0.3 or a checkout (a few minutes ago) from
the svn repository.
2. Used Components and their Configuration:
*** mod_perl version 2.000004
*** using /usr/local/lib/perl/5.8.8/Apache2/BuildConfig.pm
*** Makefile.PL options:
MP_APR_LIB => aprext
MP_APXS => /usr/bin/apxs
MP_COMPAT_1X => 1
MP_GENERATE_XS => 1
MP_LIBNAME => mod_perl
MP_USE_DSO => 1
*** The httpd binary was not found
$ apache2ctl -V
Server version: Apache/2.2.3
Server built: Feb 5 2007 02:13:07
Server's Module Magic Number: 20051115:3
Server loaded: APR 1.2.7, APR-Util 1.2.7
Compiled using: APR 1.2.7, APR-Util 1.2.7
Architecture: 32-bit
Server MPM: Prefork
threaded: no
forked: yes (variable process count)
Server compiled with....
-D APACHE_MPM_DIR="server/mpm/prefork"
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
-D APR_USE_SYSVSEM_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D DYNAMIC_MODULE_LIMIT=128
-D HTTPD_ROOT=""
-D SUEXEC_BIN="/usr/lib/apache2/suexec"
-D DEFAULT_PIDLOG="/var/run/apache2.pid"
-D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
-D DEFAULT_LOCKFILE="/var/run/apache2/accept.lock"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="/etc/apache2/mime.types"
-D SERVER_CONFIG_FILE="/etc/apache2/apache2.conf"
*** (apr|apu)-config linking info
-L/usr/lib -laprutil-1
-L/usr/lib -lapr-1 -luuid -lrt -lcrypt -lpthread -ldl
*** /usr/bin/perl -V
Summary of my perl5 (revision 5 version 8 subversion 8) configuration:
Platform:
osname=linux, osvers=2.6.18.3, archname=i486-linux-gnu-thread-multi
uname='linux saens 2.6.18.3 #1 smp sat nov 25 13:39:52 est 2006 i686
gnulinux '
config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN
-Dcccdlflags=-fPIC -Darchname=i486-linux-gnu -Dprefix=/usr
-Dprivlib=/usr/share/perl/5.8 -Darchlib=/usr/lib/perl/5.8 -Dvendorprefix=/usr
-Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5
-Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.8.8
-Dsitearch=/usr/local/lib/perl/5.8.8 -Dman1dir=/usr/share/man/man1
-Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1
-Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl
-Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Uusesfio -Uusenm -Duseshrplib
-Dlibperl=libperl.so.5.8.8 -Dd_dosuid -des'
hint=recommended, useposix=true, d_sigaction=define
usethreads=define use5005threads=undef useithreads=define
usemultiplicity=define
useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
use64bitint=undef use64bitall=undef uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler:
cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN
-fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64',
optimize='-O2',
cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN
-fno-strict-aliasing -pipe -I/usr/local/include'
ccversion='', gccversion='4.1.2 20061115 (prerelease) (Debian 4.1.1-20)',
gccosandvers=''
intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=8
alignbytes=4, prototype=define
Linker and Libraries:
ld='cc', ldflags =' -L/usr/local/lib'
libpth=/usr/local/lib /lib /usr/lib
libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
perllibs=-ldl -lm -lpthread -lc -lcrypt
libc=/lib/libc-2.3.6.so, so=so, useshrplib=true, libperl=libperl.so.5.8.8
gnulibc_version='2.3.6'
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib'
Characteristics of this binary (from libperl):
Compile-time options: MULTIPLICITY PERL_IMPLICIT_CONTEXT
PERL_MALLOC_WRAP THREADS_HAVE_PIDS USE_ITHREADS
USE_LARGE_FILES USE_PERLIO USE_REENTRANT_API
Built under linux
Compiled at Dec 6 2006 23:05:53
%ENV:
PERL5LIB="/home/stephane/lib/perl"
PERL_LWP_USE_HTTP_10="1"
@INC:
/home/stephane/lib/perl
/etc/perl
/usr/local/lib/perl/5.8.8
/usr/local/share/perl/5.8.8
/usr/lib/perl5
/usr/share/perl5
/usr/lib/perl/5.8
/usr/share/perl/5.8
/usr/local/lib/site_perl
.
*** Packages of interest status:
Apache2 : -
Apache2::Request : -
CGI : 3.15
ExtUtils::MakeMaker: 6.30_01
LWP : 5.805
mod_perl : -
mod_perl2 : 2.000004
$ svn info
Path: .
URL: https://svn.apache.org/repos/asf/perl/modperl/trunk
Repository Root: https://svn.apache.org/repos/asf
Repository UUID: 13f79535-47bb-0310-9956-ffa450edef68
Revision: 523256
Node Kind: directory
Schedule: normal
Last Changed Author: geoff
Last Changed Rev: 522508
Last Changed Date: 2007-03-26 14:04:00 +0100 (Mon, 26 Mar 2007)
Best regards,
Stephane
