Restore the original terminal pgrp after editing

[millert]

This fixes a problem when the shell is not in monitor mode (job control enabled) which resulted in the terminal pgrp being set to an invalid value once vipw exited. Fixes #1194.

[alejandro-colomar]

Tested-by: Alejandro Colomar <[email protected]>
Reviewed-by: Alejandro Colomar <[email protected]>

alx@devuan:/srv/alx/src/shadow/shadow/master$ sudo bash
[sudo] password for alx: 
root@devuan:/srv/alx/src/shadow/shadow/master# set +m
root@devuan:/srv/alx/src/shadow/shadow/master# ./src/vipw
vipw: /etc/passwd is unchanged
root@devuan:/srv/alx/src/shadow/shadow/master# 
root@devuan:/srv/alx/src/shadow/shadow/master# exit
exit

Thanks!

[alejandro-colomar]

I've applied some amendments to the commit (commit message formatting, and also removal of white space in source code):

$ git range-diff mt/master mt/pgrp_fix pgrp_fix 
1:  d61b626c ! 1:  7dcb9a0a Restore the original terminal pgrp after editing
    @@ Metadata
     Author: Todd C. Miller <[email protected]>
     
      ## Commit message ##
    -    Restore the original terminal pgrp after editing
    +    src/vipw.c: Restore the original terminal pgrp after editing
     
         This fixes a problem when the shell is not in monitor mode (job control
         enabled) which resulted in the terminal pgrp being set to an invalid
    -    value once vipw exited.  Fixes #1194.
    +    value once vipw exited.
    +
    +    Fixes: 7eca1112fbd7 (2019-11-11; "Fix vipw not resuming correctly when suspended")
    +    Closes: <https://github.com/shadow-maint/shadow/issues/1194>
    +    Reported-by: <https://github.com/yonecle>
    +    Tested-by: Alejandro Colomar <[email protected]>
    +    Reviewed-by: Alejandro Colomar <[email protected]>
     
      ## src/vipw.c ##
     @@ src/vipw.c: vipwedit (const char *file, int (*file_lock) (void), int (*file_unlock) (void))
    @@ src/vipw.c: vipwedit (const char *file, int (*file_lock) (void), int (*file_unlo
     +  if (orig_pgrp != -1) {
     +           /* Restore terminal pgrp after editing. */
     +          if (tcsetpgrp(STDIN_FILENO, orig_pgrp) == -1) {
    -+                  fprintf (stderr, "%s: %s: %s", Prog,
    -+                           "tcsetpgrp", strerror (errno));
    ++                  fprintf(stderr, "%s: %s: %s", Prog,
    ++                          "tcsetpgrp", strerror(errno));
     +          }
                sigprocmask(SIG_SETMASK, &omask, NULL);
     +  }

[alejandro-colomar]

Cc: @yonecle

[alejandro-colomar]

Since nobody else has commented, and the experiment seems to confirm this is good, I'll merge now. Thanks!