ash,hush: fix $RANDOM in children being repeated

function                                             old     new   delta
next_random                                           46      68     +22
forkshell                                            248     263     +15
expand_vars_to_list                                 2118    2131     +13
run_pipe                                            1775    1782      +7
popstring                                            134     140      +6
builtin_umask                                        123     121      -2
ash_main                                            1356    1336     -20
get_local_var_value                                  125     104     -21
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/3 up/down: 63/-43)             Total: 20 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/shell/hush.c b/shell/hush.c
index d105029ff..21f3edcac 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -88,6 +88,8 @@
 #include "match.h"
 #if ENABLE_HUSH_RANDOM_SUPPORT
 # include "random.h"
+#else
+# define CLEAR_RANDOM_T(rnd) ((void)0)
 #endif
 #ifndef PIPE_BUF
 # define PIPE_BUF 4096  /* amount of buffering in a pipe */
@@ -1319,8 +1321,6 @@ static const char *get_local_var_value(const char *name)
         // bash compat: UID? EUID?
 #if ENABLE_HUSH_RANDOM_SUPPORT
         if (strcmp(name, "RANDOM") == 0) {
-                if (G.random_gen.galois_LFSR == 0)
-                        INIT_RANDOM_T(&G.random_gen, G.root_pid, monotonic_us());
                 return utoa(next_random(&G.random_gen));
         }
 #endif
@@ -4000,6 +4000,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
                 if (!command->pid) { /* child */
 #if ENABLE_HUSH_JOB
                         disable_restore_tty_pgrp_on_exit();
+                        CLEAR_RANDOM_T(&G.random_gen); /* or else $RANDOM repeats in child */
 
                         /* Every child adds itself to new process group
                          * with pgid == pid_of_first_child_in_pipe */
@@ -5207,6 +5208,7 @@ static FILE *generate_stream_from_string(const char *s)
                         + (1 << SIGTTIN)
                         + (1 << SIGTTOU)
                         , SIG_IGN);
+                CLEAR_RANDOM_T(&G.random_gen); /* or else $RANDOM repeats in child */
                 close(channel[0]); /* NB: close _first_, then move fd! */
                 xmove_fd(channel[1], 1);
                 /* Prevent it from trying to handle ctrl-z etc */