srfsh can segfault if .srfsh_history is empty

[Galen Charlton]

If ~/.srfsh_history is empty (as might happen if one cleared the request history by cat'ing /dev/null into it), using readline commands to try to retrieve history items causes srfsh to segfault.

For example:

$ cat /dev/null > ~/.srfsh_history
$ srfsh # then hit the up arrow key

OpenSRF master

[Galen Charlton (gmc)]

Note that a segfault does not happen if ~/.srfsh_history was not present to begin with.

[Galen Charlton (gmc)]

Some more details:

Platform: Debian 7.8

Back trace of the segfault:

#0 0x00007fa21ff88adc in previous_history () from /lib/x86_64-linux-gnu/libreadline.so.5
#1 0x00007fa21ff88645 in rl_get_previous_history () from /lib/x86_64-linux-gnu/libreadline.so.5
#2 0x00007fa21ff716a0 in _rl_dispatch_subseq () from /lib/x86_64-linux-gnu/libreadline.so.5
#3 0x00007fa21ff718d1 in _rl_dispatch_subseq () from /lib/x86_64-linux-gnu/libreadline.so.5
#4 0x00007fa21ff718d1 in _rl_dispatch_subseq () from /lib/x86_64-linux-gnu/libreadline.so.5
#5 0x00007fa21ff71c60 in readline_internal_char () from /lib/x86_64-linux-gnu/libreadline.so.5
#6 0x00007fa21ff72105 in readline () from /lib/x86_64-linux-gnu/libreadline.so.5
#7 0x00000000004026b4 in get_request () at srfsh.c:242
#8 main (argc=<optimized out>, argv=<optimized out>) at srfsh.c:165

libreadline6 package version: 6.2+dfsg-0.1

[Jason Boyer (jboyer)]

There's a fix for this here: https://git.evergreen-ils.org/?p=working/OpenSRF.git;a=shortlog;h=refs/heads/user/jboyer/lp1461978_history_segfault / working/user/jboyer/lp1461978_history_segfault

Testing notes:
1. Pre-patch, setup OpenSRF and srfsh so srfsh can be used successfully
2. Set $HOME/.srfsh_history to a 0 size with truncate or create it with touch
3. run srfsh and press the up arrow to try to retrieve a history entry
4. Segfault

Apply patch and repeat steps above. This time step 4 should be "Become annoyed at the BEL being sent through your speakers."