$HOME not set and zsh crashing in emulation mode

$HOME not set and zsh crashing in emulation mode

[Paulo César Pereira de Andrade]

  A simple reproducer:

"""
$ cat t.sh
#!/bin/sh
echo $HOME

$ ln -sf /bin/zsh ksh

$ ./ksh -n t.sh
Segmentation fault (core dumped)
"""

  This probably is not correct, but a possible patch is:
---8<---
--- zsh-5.0.2/Src/init.c.orig    2016-10-27 15:36:29.210875166 -0200
+++ zsh-5.0.2/Src/init.c    2016-10-27 15:36:33.581867451 -0200
@@ -963,7 +963,7 @@ setupvals(void)
     if (EMULATION(EMULATE_ZSH))
     ptr = home;
     else
-    ptr = zgetenv("HOME");
+    ptr = home = zgetenv("HOME");
     if (ptr && ispwd(ptr))
     pwd = ztrdup(ptr);
     else if ((ptr = zgetenv("PWD")) && (strlen(ptr) < PATH_MAX) &&
---8<---

  The problem happens because when importing the
environment, setstrvalue will return too early with -n,
but will always set HOME if not in emulation mode:

mod_export void
setstrvalue(Value v, char *val)
{
    if (unset(EXECOPT))
    return;

  From gdb:

(gdb) b setstrvalue
(gdb) cond 1 (strcmp(val, "/home/pcpa") == 0)
Breakpoint 1, setstrvalue (val=0x6e0b00 "/home/pcpa",
v=0x7fffffffd950) at params.c:2267
2267        if (unset(EXECOPT))
(gdb) bt
#0  setstrvalue (val=0x6e0b00 "/home/pcpa", v=0x7fffffffd950) at params.c:2267
#1  assignsparam (s=0x7ffff7ff5cc4 "", s@entry=0x7ffff7ff5cc0 "HOME",
val=0x6e0b00 "/home/pcpa", flags=<optimized out>, flags@entry=0)
    at params.c:2738
#2  0x00000000004712fe in createparamtable () at params.c:737
#3  0x000000000044823f in setupvals () at init.c:988
#4  0x000000000044a1ac in zsh_main (argc=<optimized out>,
argv=<optimized out>) at init.c:1596
#5  0x000000000040e3f0 in main (argc=3, argv=0x7fffffffde78) at ./main.c:93

Thanks,
Paulo

Re: $HOME not set and zsh crashing in emulation mode

[Bart Schaefer]

This was fixed by workers/36780 about a year ago.

Re: $HOME not set and zsh crashing in emulation mode

[Daniel Shahaf]

Paulo César Pereira de Andrade wrote on Thu, Oct 27, 2016 at 15:51:43 -0200:
>   A simple reproducer:
> 
> """
> $ cat t.sh
> #!/bin/sh
> echo $HOME
> 
> $ ln -sf /bin/zsh ksh
> 
> $ ./ksh -n t.sh
> Segmentation fault (core dumped)
> """

You're using 5.0.2, which is four years old.  We've fixed this bug in
5.2 last year:

    commit 83a175795a444e8169fcb592a110d4d15a09b907
    Author: Peter Stephenson <pws@zsh.org>
    Date:   Tue Oct 6 09:28:07 2015 +0100
    
        36780: Fix crash in ksh mode with -n and $HOME.
        
        If home variable is NULL ensure HOME is unset.

Current master does not have the problem:

% ARGV0=ksh Src/zsh -fn =(<<<$'#!/bin/sh\necho $HOME\n') 
% 

Thanks for the bug report and the patch.

Cheers,

Daniel

Re: $HOME not set and zsh crashing in emulation mode

[Paulo César Pereira de Andrade]

2016-10-27 18:19 GMT-02:00 Daniel Shahaf <d.s@daniel.shahaf.name>:

>> """
>> $ cat t.sh
>> #!/bin/sh
>> echo $HOME
>>
>> $ ln -sf /bin/zsh ksh
>>
>> $ ./ksh -n t.sh
>> Segmentation fault (core dumped)
>> """
>
> You're using 5.0.2, which is four years old.  We've fixed this bug in
> 5.2 last year:
>
>     commit 83a175795a444e8169fcb592a110d4d15a09b907
>     Author: Peter Stephenson <pws@zsh.org>
>     Date:   Tue Oct 6 09:28:07 2015 +0100
>
>         36780: Fix crash in ksh mode with -n and $HOME.
>
>         If home variable is NULL ensure HOME is unset.
>
> Current master does not have the problem:
>
> % ARGV0=ksh Src/zsh -fn =(<<<$'#!/bin/sh\necho $HOME\n')
> %
>
> Thanks for the bug report and the patch.

  Sorry for not checking latest sources before reporting
upstream. Will do so next time :)

  I updated the bug report with the patch at
https://bugzilla.redhat.com/show_bug.cgi?id=1389492

> Cheers,
>
> Daniel

Thanks,
Paulo