344411: $RANDOM stays the same when job executed in the background

In bash 3.0, random was seeded whenever subshell_environment != 0.

In bash 3.2, random was seeded whenever subshell_environment != 0 &&

seeded_subshell == 0. And when it was seeded, seeded_subshell was set to 1.

Therefore, in 3.2, if you seeded random in a subshell and in this subshell

invoked another one, it wasn't reseeded as it should have been. A testcase for

that is this:

    ( echo $RANDOM; ( echo $RANDOM ); ( echo $RANDOM ) )

Tomas's patch (bash-3.2-rng.patch) changed the code to use subshell_level.

subshell_level is not increased for simple async commands, however. So,

although he fixed the previous case, he introduced another. Here's a testcase:

    echo $RANDOM; echo $RANDOM & echo $RANDOM &

I decided to just compare the pids, that should be safe enough.

Written-by: Tomas Janousek <tjanouse@redhat.com>

Reviewed-by: Tomas Mraz <tmraz@redhat.com>

--- bash-3.2/variables.c.344411	2007-11-06 19:26:42.000000000 +0100

+++ bash-3.2/variables.c	2007-11-06 20:27:25.000000000 +0100

@@ -1211,7 +1211,7 @@

      arrayind_t unused;

 {

   sbrand ((unsigned int)strtoul (value, (char **)NULL, 10));

-  seeded_subshell = subshell_level;

+  seeded_subshell = getpid();

   return (self);

 }

@@ -1221,10 +1221,10 @@

   int rv;

   /* Reset for command and process substitution. */

-  if (seeded_subshell < subshell_level)

+  if (seeded_subshell != getpid())

     {

       seed_random ();

-      seeded_subshell = subshell_level;

+      seeded_subshell = getpid();

     }

   do