Osmocom Libraries » libosmocore

From fixeria :

 The problem is somewhere in cmd_execute_command_real(). Instead of composing 'argv' from 'vline', we need to use 'matched_element'.

Some info from gdb:
  $ gdb -q ./vty_transcript_test
  (gdb)$ b command.c:2322
  $ telnet localhost 42042
  $ vty_transcript_test> th
  (gdb)$ bt
    #0  cmd_execute_command_real (vline=0x62ac30, vty=0x6295e0, cmd=0x0) at command.c:2321
    #1  0x00007ffff7767575 in cmd_execute_command (vline=0x62ac30, vty=0x6295e0, cmd=0x0, vtysh=0x0) at command.c:2354
    #2  0x00007ffff776ab79 in vty_command (vty=0x6295e0, buf=0x629790 "multi0 th") at vty.c:431
    #3  0x00007ffff776b3a0 in vty_execute (vty=0x6295e0) at vty.c:695
    #4  0x00007ffff776cf8c in vty_read (vty=0x6295e0) at vty.c:1419
    #5  0x00007ffff776f5f1 in client_data (fd=0x629538, what=0x1) at telnet_interface.c:147
    #6  0x00007ffff7ba01c4 in osmo_fd_disp_fds (_rset=0x7fffffffda20, _wset=0x7fffffffdaa0, _eset=0x7fffffffdb20) at select.c:223
    #7  0x00007ffff7ba0349 in osmo_select_main (polling=0x0) at select.c:263
    #8  0x00000000004016d2 in main (argc=0x1, argv=0x7fffffffdcb8) at vty/vty_transcript_test.c:232
    #9  0x00007ffff73b3f45 in __libc_start_main (main=0x40154b <main>, argc=0x1, argv=0x7fffffffdcb8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffdca8) at libc-start.c:287
#10 0x00000000004010f9 in _start ()
  (gdb)$ p (char *) (vline->index[0])
    $131 = 0x62ad20 "multi0" 
  (gdb)$ p (char *) (vline->index[1])
    $132 = 0x62ad90 "th" 
  (gdb)$ p (char *) *((struct _vector *)((struct _vector *)((struct _vector *)(matched_element->strvec->index[0])))->index[0])
    $133 = 0x626400 "multi0" 
  (gdb)$ p (char *) *((struct _vector *)((struct _vector *)((struct _vector *)(matched_element->strvec->index[1])))->index[0])
    $134 = 0x626660 "one" 
  (gdb)$ p (char *) *((struct _vector *)((struct _vector *)((struct _vector *)(matched_element->strvec->index[1])))->index[1])
    $135 = 0x626390 "two" 
  (gdb)$ p (char *) *((struct _vector *)((struct _vector *)((struct _vector *)(matched_element->strvec->index[1])))->index[2])
    $136 = 0x626840 "three" 

fixeria also submitted a patch to showcase the issue in this libosmocore test:
https://gerrit.osmocom.org/c/libosmocore/+/14307/

Fixed what could be a related issue in here:
https://gerrit.osmocom.org/c/libosmocore/+/14422 vty: command.c: Fix is_cmd_ambiguous() returning always 0

But I don't think it's fixing the whole issue.

At least it finds some more ambiguous commands:

vty_transcript_test> multi0 t
% Ambiguous command.
Error during transcript step 6:
[
vty_transcript_test> multi0 t
ok argc=1 t
]
Error while verifying transcript file '/home/osmocom-build/jenkins/workspace/gerrit-libosmocore/a2/default/a3/default/a4/default/arch/amd64/label/osmocom-gerrit-debian9/tests/vty/vty_transcript_test.vty'
signal 15 received
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/osmopython-0.1.0-py3.5.egg/osmopy/osmo_interact/common.py", line 362, in verify_application
    interact.verify_transcript_file(transcript_file)
  File "/usr/local/lib/python3.5/dist-packages/osmopython-0.1.0-py3.5.egg/osmopy/osmo_interact/common.py", line 116, in verify_transcript_file
    result = self.verify_transcript(content)
  File "/usr/local/lib/python3.5/dist-packages/osmopython-0.1.0-py3.5.egg/osmopy/osmo_interact/common.py", line 205, in verify_transcript
    % (match_result, step, step.command_str(), '\n'.join(res)))
Exception: Result mismatch:
Mismatch:
Expect:
'ok argc=1 t'
Got:
'% Ambiguous command.'

I have a fix for this issue already in my pespin/vty branch, but I found a related issue for single-choice optional parameters, which is showcased in this test:
https://gerrit.osmocom.org/c/libosmocore/+/14431 vty: tests: Verify incomplete optional parameters are passed to vty funcs

Once I fix that issue (related code), then I'll submit fixes for both together.

Both issues should be fixed by:
https://gerrit.osmocom.org/c/libosmocore/+/14436 vty: command.c: Fix: multi-choice args are no longer passed incomplete to vty func
https://gerrit.osmocom.org/c/libosmocore/+/14437 vty: command.c: Fix: single-choice optional args are no longer passed to vty func

Once merged we can close the ticket.

Assigning to fixeria so he can check that initial issue found while using VTY is indeed fixed.

I am happy to confirm that the problem has been resolved. No segfaults anymore. Thanks Pau!