I am using shellinabox on an embedded device which uses a simple "cgi-GUI" to
its "services". The daemons are started and then a "status" is displayed on a
cgi-page.
Starting shellinabox as a daemon will continue to load this page "for ever", so
the webserver seemed to be waiting for an open filedescriptor to close. You
will see open fds after starting shellinaboxd with "-b" option.
What steps will reproduce the problem?
1. running "shellinaboxd -b"
2. running "lsof" will show open fd's
3.
What is the expected output? What do you see instead?
running "lsof" will show open filedescriptors to pty's, so from my point of
view shellinabox is not "fully daemonized". (Note, only the fork in
shellinaboxd.c shows this, the other forks [from "launcher.c"] seem to
close/redirect them correctly [to /dev/null]):
/var/tmp # shellinaboxd -b --pidfile=/var/run/shellinaboxd.pid -c
/tmp/shellinabox -p 4200 -u nobody
/var/tmp # lsof -n | grep shellin
shellinab 16832 nobody cwd DIR 0,10 1580 57 /var/tmp
shellinab 16832 nobody rtd DIR 31,0 213 201 /
shellinab 16832 nobody txt REG 31,0 1215808 1399
/usr/bin/shellinaboxd
shellinab 16832 nobody 0u CHR 136,0 0t0 2 /dev/pts/0
shellinab 16832 nobody 1u CHR 136,0 0t0 2 /dev/pts/0
shellinab 16832 nobody 2u CHR 136,0 0t0 2 /dev/pts/0
shellinab 16832 nobody 3u unix 0x8493f240 0t0 238327 socket
shellinab 16832 nobody 4u IPv4 238338 0t0 TCP *:4200
(LISTEN)
shellinab 16833 nobody cwd DIR 0,10 1580 57 /var/tmp
shellinab 16833 nobody rtd DIR 31,0 213 201 /
shellinab 16833 nobody txt REG 31,0 1215808 1399
/usr/bin/shellinaboxd
shellinab 16833 nobody 0u CHR 1,3 0t0 154 /dev/null
shellinab 16833 nobody 1u CHR 1,3 0t0 154 /dev/null
shellinab 16833 nobody 2u CHR 136,0 0t0 2 /dev/pts/0
shellinab 16833 nobody 4u unix 0x86b6ede0 0t0 238328 socket
/var/tmp #
Using "daemon()" of glibc or ulibc instead (see patch below), shows the
expected behavior:
/var/tmp # killall shellinaboxd
/var/tmp # /tmp/shellinaboxd -b --pidfile=/var/run/shellinaboxd.pid -c
/tmp/shellinabox -p 4200 -u nobody
/var/tmp # lsof -n | grep shellin
shellinab 17315 nobody cwd DIR 31,0 213 201 /
shellinab 17315 nobody rtd DIR 31,0 213 201 /
shellinab 17315 nobody txt REG 0,10 1217952 183496
/var/tmp/shellinaboxd
shellinab 17315 nobody 0u CHR 1,3 0t0 154 /dev/null
shellinab 17315 nobody 1u CHR 1,3 0t0 154 /dev/null
shellinab 17315 nobody 2u CHR 1,3 0t0 154 /dev/null
shellinab 17315 nobody 3u unix 0x8493f240 0t0 238696 socket
shellinab 17315 nobody 4u IPv4 238707 0t0 TCP *:4200
(LISTEN)
shellinab 17316 nobody cwd DIR 31,0 213 201 /
shellinab 17316 nobody rtd DIR 31,0 213 201 /
shellinab 17316 nobody txt REG 0,10 1217952 183496
/var/tmp/shellinaboxd
shellinab 17316 nobody 0u CHR 1,3 0t0 154 /dev/null
shellinab 17316 nobody 1u CHR 1,3 0t0 154 /dev/null
shellinab 17316 nobody 2u CHR 1,3 0t0 154 /dev/null
shellinab 17316 nobody 4u unix 0x84aa8e00 0t0 238697 socket
/var/tmp #
What version of the product are you using? On what operating system?
I'm using version shellinabox-2.14 (though it shows "ShellInABox version 2.10
(revision 239)") on a mips-linux device.
Exactly the same behaviour on my Ubuntu 12.10 Linux System.
Please provide any additional information below.
I only found "the problem", all credits for the "solution" go to Oliver Metz. I
used this simple patch of him to get the "corrected" output:
--- shellinabox/shellinaboxd.c.orig 2012-04-21 19:30:44.000000000 +0200
+++ shellinabox/shellinaboxd.c 2012-12-27 18:45:33.000000000 +0100
@@ -1159,12 +1159,9 @@
}
if (demonize) {
- pid_t pid;
- check((pid = fork()) >= 0);
- if (pid) {
- _exit(0);
+ if (daemon(0, 0) < 0) {
+ fatal("Failed to daemonize: %s", strerror(errno));
}
- setsid();
}
if (pidfile) {
#ifndef O_LARGEFILE
Original issue reported on code.google.com by joerg.ei...@googlemail.com on 28 Dec 2012 at 1:09
Original issue reported on code.google.com by
joerg.ei...@googlemail.comon 28 Dec 2012 at 1:09