lib/utmp.c: is_my_tty(): Simplify

[alejandro-colomar]

Let's keep it simple.

---

Revisions:

v2

• Fix intermediate commit. [@hallyn ]

$ git rd 
1:  0d6e5f800 = 1:  0d6e5f800 lib/utmp.c: is_my_tty(): Don't cache ttyname(3).
2:  fa3a25919 ! 2:  120ad06c1 lib/utmp.c: is_my_tty(): Rename local variable
    @@ lib/utmp.c: static bool
        strncat(full_tty, tty, UTX_LINESIZE);
      
     -  tmptty = ttyname(STDIN_FILENO);
    +-  if (NULL != tmptty)
     +  my_tty = ttyname(STDIN_FILENO);
    -   if (NULL != tmptty)
    ++  if (NULL != my_tty)
                (void) puts (_("Unable to determine your tty name."));
                exit (EXIT_FAILURE);
        }
3:  b7b40d6a5 ! 3:  379d10c2d lib/utmp.c: is_my_tty(): Use ttyname_r(3) to make it re-entrant
    @@ lib/utmp.c
        strncat(full_tty, tty, UTX_LINESIZE);
      
     -  my_tty = ttyname(STDIN_FILENO);
    --  if (NULL != tmptty)
    +-  if (NULL != my_tty)
     +  if (ttyname_r(STDIN_FILENO, my_tty, countof(my_tty)) != 0) {
                (void) puts (_("Unable to determine your tty name."));
                exit (EXIT_FAILURE);
4:  993fc4e7f = 4:  2fc993adb lib/utmp.c: ttyname_ra(): Add macro

v2b

• Reviewed-by @hallyn

$ git rd 
1:  0d6e5f800 ! 1:  a1cb667e7 lib/utmp.c: is_my_tty(): Don't cache ttyname(3).
    @@ Commit message
         ttyname(3), we use it directly, without needing a temporary copy, which
         removes opportunities for bugs.
     
    +    Reviewed-by: Serge Hallyn <serge@hallyn.com>
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
      ## lib/utmp.c ##
2:  120ad06c1 ! 2:  c4ca166ba lib/utmp.c: is_my_tty(): Rename local variable
    @@ Commit message
     
         This name makes the function definition more readable.
     
    +    Reviewed-by: Serge Hallyn <serge@hallyn.com>
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
      ## lib/utmp.c ##
3:  379d10c2d ! 3:  6ac300300 lib/utmp.c: is_my_tty(): Use ttyname_r(3) to make it re-entrant
    @@ Metadata
      ## Commit message ##
         lib/utmp.c: is_my_tty(): Use ttyname_r(3) to make it re-entrant
     
    +    Reviewed-by: Serge Hallyn <serge@hallyn.com>
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
      ## lib/utmp.c ##
4:  2fc993adb ! 4:  7d02a222d lib/utmp.c: ttyname_ra(): Add macro
    @@ Commit message
     
         This macro enforces correct use of ttyname_r(3) with arrays.
     
    +    Reviewed-by: Serge Hallyn <serge@hallyn.com>
         Signed-off-by: Alejandro Colomar <alx@kernel.org>
     
      ## lib/utmp.c ##

[hallyn]

I know it doesn't affect the end result, but patch two can't compile because you didn't change all instances of the ttyname variable.

[alejandro-colomar]

I know it doesn't affect the end result, but patch two can't compile because you didn't change all instances of the ttyname variable.

Oops, my bad. Thanks! Will fix.

[alejandro-colomar]

I know it doesn't affect the end result, but patch two can't compile because you didn't change all instances of the ttyname variable.

Done. Thanks!

(I suspect it was the result of reordering commits.)