On Fri, Dec 2, 2016 at 12:59 PM, Clark Wang <dearv...@gmail.com> wrote:
> On Fri, Dec 2, 2016 at 6:28 AM, Vladimir Marek <vladimir.ma...@oracle.com>
> wrote:
>
>> Hi,
>>
>> I'm not sure what is going on, but the bash test suite was getting
>> stopped (as if SIGSTOP was received) in the middle. Trying to find
>> minimal set of conditions it came to this:
>>
>> - my ~/.bashrc has to contain 'cd /' (any dir works)
>> - the tests have to first execute run-execscript, namely it has to
>> execute exec6.sub, namely the line ${THIS_SH} -i ./exec8.sub
>> - the file exec8.sub is reported as not found (I presume because of the
>> 'cd /' in .bashrc)
>> - the tests then have to run read-test, exactly in read2.sub when
>> 'read -t 2 a < /dev/tty' was executed whole thing was stopped
>>
>> When I removed the 'cd' command from my ~/.bashrc, all worked fine.
>>
>> I then tried to make minimal reproducible case and came to this (this
>> time there is no 'cd /' in my ~/.bashrc needed):
>>
>> $ bash -c 'bash -i i; bash -i i'
>> bash -c 'bash -i i; bash -i i'
>> bash: i: No such file or directory
>>
>> [1]+ Stopped bash -c 'bash -i i; bash -i i'
>>
>
> I can reproduce this with bash 4.4.5 on Debian 8.5.
>
> foo@deb64:~$ bash -c 'bash -i 1; bash -i 2'
> bash: 1: No such file or directory
>
> [1]+ Stopped bash -c 'bash -i 1; bash -i 2'
> foo@deb64:~$ echo $?
> 149
>
> It was stopped by SIGTTIN. According to gdb backtrace it was killed by the
> second "bash -i".
>
> 4099 while ((terminal_pgrp = tcgetpgrp (shell_tty)) != -1)
> 4100 {
> 4101 if (shell_pgrp != terminal_pgrp)
> 4102 {
> 4103 SigHandler *ottin;
> 4104
> 4105 ottin = set_signal_handler (SIGTTIN, SIG_DFL);
> 4106 kill (0, SIGTTIN);
> 4107 set_signal_handler (SIGTTIN, ottin);
> 4108 continue;
> 4109 }
> 4110 break;
> 4111 }
>
> The problem is tcgetpgrp() still returns the pgrp of the first "bash -i"
> when the second "bash -i" is running. This can be shown with following
> example:
>
> foo@deb64:~$ bash -c 'bash -i 1; sleep 9999'
> bash: 1: No such file or directory <-- CTRL-C does not work here
>
> root@deb64:~# ps t pts/10 j
> PPID PID PGID SID TTY TPGID STAT UID TIME COMMAND
> 96886 96887 96887 96887 pts/10 97073 Ss 1001 0:00 -bash
> 96887 97072 97072 96887 pts/10 97073 S 1001 0:00 bash -c
> bash -i 1; sleep 9999
> 97072 97074 97072 96887 pts/10 97073 S 1001 0:00 sleep 9999
>
> Here the TPGID 97073 must be the first "bash -i" which has already exited.
> Seems like for some reason the "bash -c" does not set the foreground pgrp
> to the second "bash -i".
>
Found the problem. The first "bash -i" changed the foreground pgrp to its
own pgrp at startup but did not restore the original foreground pgrp when
it exited. The following patch (not a real fix) works for me:
--- a/shell.c
+++ b/shell.c
@@ -1504,6 +1504,7 @@ open_shell_script (script_name)
{
e = errno;
file_error (filename);
+ end_job_control ();
sh_exit ((e == ENOENT) ? EX_NOTFOUND : EX_NOINPUT);
}
