slmodemd fails with setgroups error

[Steve Graham]

Binary package hint: sl-modem-daemon

NOTE: my kernel is not a standard Ubuntu build, but for information:

With both the original default 9.04 install and Ahmed's latest test package, slmodemd terminates with the error "error: setgroups or setgid 120 or setuid 112 failed: Invalid argument". If I replace the /usr/sbin/slmodemd binary with the latest from the original devloper's site, the error does not occur, and the modem can be used successfully.

With the ubuntu builds, the error goes away if I add the "-n" option -- no realtime -- to the daemon's arguments. However, I don't know if this workaround results in a 100% reliable modem.

Given the latter, I wondered if the actual error message was bogus, and the real problem was related to /etc/security/limits.conf but changes there had no effect. The ulimit command in the startup script seems cover that in any case.

Debug - same result from sl-modem-daemon_2.9.11~20080817-3ubuntu2_i386.deb
 and ppa sl-modem-daemon_2.9.11~20090222-2~5.gbpb41b1b_i386.deb

bash-3.2# ./slmodemd.u-orig -c UK --alsa --debug 7
SmartLink Soft Modem: version 2.9.11 Mar 6 2009 00:36:34
<062.028457> SmartLink Soft Modem: version 2.9.11 Mar 6 2009 00:36:34
<062.028595> modem:1: startup modem...
<062.028806> modem:1: update termios...
symbolic link `/dev/ttySL0' -> `/dev/pts/0' created.
modem `modem:1' created. TTY is `/dev/pts/0'
<062.029911> open file: /var/lib/slmodem/data.modem:1...
<062.030996> main: rt applyed: SCHED_FIFO, pri 99
error: setgroups or setgid 120 or setuid 112 failed: Invalid argument

Result with binary from
http://linmodems.technion.ac.il/packages/smartlink/SLMODEMD_gcc4.3_alsa1.0.18.tar.gz

bash-3.2# ./slmodem-u-latest -c UK --alsa --debug 7
SmartLink Soft Modem: version 2.9.11 Aug 16 2009 18:13:25
<205.053021> SmartLink Soft Modem: version 2.9.11 Aug 16 2009 18:13:25
<205.053169> modem:1: startup modem...
<205.053377> modem:1: update termios...
symbolic link `/dev/ttySL0' -> `/dev/pts/0' created.
modem `modem:1' created. TTY is `/dev/pts/0'
<205.054465> open file: /var/lib/slmodem/data.modem:1...
<205.055498> main: rt applyed: SCHED_FIFO, pri 99
error: setgroups or setgid 120 or setuid 112 failed: Invalid argument
bash-3.2# ./slmodemd.orig-latest -c UK --alsa --debug 7
SmartLink Soft Modem: version 2.9.11 Feb 25 2009 18:35:08
<252.211850> SmartLink Soft Modem: version 2.9.11 Feb 25 2009 18:35:08
<252.211989> modem:1: startup modem...
<252.212243> modem:1: update termios...
symbolic link `/dev/ttySL0' -> `/dev/pts/0' created.
modem `modem:1' created. TTY is `/dev/pts/0'
<252.213351> open file: /var/lib/slmodem/data.modem:1...
<252.246340> main: rt applyed: SCHED_FIFO, pri 99
Use `/dev/ttySL0' as modem device, Ctrl+C for termination.

ProblemType: Bug
Architecture: i386
Dependencies:

DistroRelease: Ubuntu 9.04
Package: sl-modem-daemon None [modified: /var/lib/dpkg/info/sl-modem-daemon.list]
ProcEnviron:
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: sl-modem
Uname: Linux 2.6.30.5-T61 i686
UnreportableReason: This is not a genuine Ubuntu package

[Steve Graham (ubuntu-annaghvarn)]

Sorry - I messed up pasting the debug there. Separate the last two at the bash prompt.

[Rolf Leggewie (r0lf)]

interesting find, thank you, especially since apparently the package works for you (there's not many like that currently ;-))