[asterisk-dev] [Code Review] 2734: Check result of ast_var_assign when out of mem

[wdoekes]

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https://reviewboard.asterisk.org/r/2734/
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Review request for Asterisk Developers.


Repository: Asterisk


Description
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Due to a different issue, my asterisk was out of memory.

It crashed first when it tried to AST_LIST_INSERT_HEAD(headp, newvariable, entries); a newvariable that was NULL.

#0  0x0000000000535b30 in pbx_builtin_setvar_helper (chan=0x7fb8fd85d368, name=0x7fb93c03ed60 "__record_call", value=0x7fb940a90240 "no") at pbx.c:10202
10202			AST_LIST_INSERT_HEAD(headp, newvariable, entries);
(gdb) back
#0  0x0000000000535b30 in pbx_builtin_setvar_helper (chan=0x7fb8fd85d368, name=0x7fb93c03ed60 "__record_call", value=0x7fb940a90240 "no") at pbx.c:10202
#1  0x00007fb94b0a4e1f in sip_new (i=0x94d7ee8, state=0, title=0x7fb940a90ce0 "152960003", linkedid=0x7fb93c058126 "somehost-1374224633.26491") at chan_sip.c:7346
#2  0x00007fb94b10d9d6 in sip_request_call (type=0x7fb940a91250 "SIP", cap=0x7fb833f3afc0, requestor=0x7fb8fd80b9c8, data=0x7fb940a92190, cause=0x7fb940a91b74) at chan_sip.c:27815
...

This patch checks all ast_var_assign() calls found in the 1.8 branch for NULL.

Note that I didn't sprinkle the code with "out of memory" log messages for three reasons: (a) you'll probably notice that you're out of mem anyway, (b) the ast_calloc already mentiones that we're out of mem, (c) the ast_log() call itself has the potential for crashing because of recursion (out of stack space) (*)


(*) E.g. here:
        /* Create a new logging message */
        if (!(logmsg = ast_calloc_with_stringfields(1, struct logmsg, res + 128)))
                return;


Diffs
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  /branches/1.8/apps/app_playback.c 396085 
  /branches/1.8/apps/app_stack.c 396085 
  /branches/1.8/funcs/func_global.c 396085 
  /branches/1.8/funcs/func_strings.c 396085 
  /branches/1.8/main/cdr.c 396085 
  /branches/1.8/main/pbx.c 396085 
  /branches/1.8/pbx/pbx_dundi.c 396085 
  /branches/1.8/pbx/pbx_loopback.c 396085 
  /branches/1.8/utils/extconf.c 396085 

Diff: https://reviewboard.asterisk.org/r/2734/diff/


Testing
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It compiles.


Thanks,

wdoekes

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