2015-04-20 14:17 GMT-03:00 Paulo César Pereira de Andrade
<[email protected]>:
[...]
>> So, after following the code enough, I learned that at places
>> it handles SH_JMPEXIT, there was almost non existing
>> handling of SH_JMPERREXIT.
>>
>> ksh would evently cause a crash due to the struct
>> subshell allocated on stack, in sh/subshell.c:sh_subshell
>> kept set to the global subshell_data, after it siglongjmp
>> back the stack due to, not fully handling the out of disk
>> space errors. It would print a few messages, everytime
>> a pipe was created, e.g.:
>>
>> /etc/profile: line 28: write to 3 failed [No space left on device]
>>
>> until eventually crashing due to corrupted memory; e.g. the
>> references to stack data from sh_subsell in the global
>> subshell_data. One strange thing to me in coredump analysis
>> was that subshell_data prev field was pointing to itself when
>> it eventually crashed, what later was understood and expected...
I think it may be better to pass 0 to sh_done, because otherwise
it would pass 255 as an argument to sigaction.
Passing 0 would cause it to exit immediately, like a
normal shell execution.
I just noticed the issue while debugging a problem
in tcsh, and ksh would fallback in the pause(), instead
of exiting, if ^C was pressed during:
eval sleep 10
Patch inlined in case it could get removed from email:
---8<---
diff -up ksh-20120801/src/cmd/ksh93/sh/main.c.orig
ksh-20120801/src/cmd/ksh93/sh/main.c
--- ksh-20120801/src/cmd/ksh93/sh/main.c.orig 2015-04-29
16:49:11.502958000 -0300
+++ ksh-20120801/src/cmd/ksh93/sh/main.c 2015-05-08 18:19:55.688776922 -0300
@@ -423,7 +423,7 @@ static void exfile(register Shell_t *shp
sfsync(shp->outpool);
shp->st.execbrk = shp->st.breakcnt = 0;
/* check for return from profile or env file */
- if(sh_isstate(SH_PROFILE) && (jmpval==SH_JMPFUN || jmpval==SH_JMPEXIT))
+ if(sh_isstate(SH_PROFILE) && (jmpval==SH_JMPFUN ||
jmpval==SH_JMPEXIT || jmpval==SH_JMPERREXIT))
{
sh_setstate(states);
goto done;
@@ -598,7 +598,7 @@ done:
}
if(jmpval == SH_JMPSCRIPT)
siglongjmp(*shp->jmplist,jmpval);
- else if(jmpval == SH_JMPEXIT)
+ else if(jmpval == SH_JMPEXIT || jmpval == SH_JMPERREXIT)
sh_done(shp,0);
if(fno>0)
sh_close(fno);
---8<---
Thanks,
Paulo
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