hush: fix thinko in re_execute_shell; pass even less junk to heredoc helper

function                                             old     new   delta
re_execute_shell                                     284     314     +30
setup_heredoc                                        290     303     +13
execv                                                 23       -     -23

1 files changed, 19 insertions, 8 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 9920e98c6..3959da1ea 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2180,10 +2180,21 @@ static void re_execute_shell(const char *s, int is_heredoc) NORETURN;
 static void re_execute_shell(const char *s, int is_heredoc)
 {
         char param_buf[sizeof("-$%x:%x:%x:%x") + sizeof(unsigned) * 4];
+        char *heredoc_argv[4];
         struct variable *cur;
         char **argv, **pp, **pp2;
         unsigned cnt;
 
+        if (is_heredoc) {
+                argv = heredoc_argv;
+                argv[0] = (char *) G.argv0_for_re_execing;
+                argv[1] = (char *) "-<";
+                argv[2] = (char *) s;
+                argv[3] = NULL;
+                pp = &argv[3]; /* used as pointer to empty environmaent */
+                goto do_exec;
+        }
+
         sprintf(param_buf, "-$%x:%x:%x" USE_HUSH_LOOPS(":%x")
                         , (unsigned) G.root_pid
                         , (unsigned) G.last_bg_pid
@@ -2198,7 +2209,7 @@ static void re_execute_shell(const char *s, int is_heredoc)
                 if (!cur->flg_export || cur->flg_read_only)
                         cnt += 2;
         }
-        G.argv_from_re_execing = pp = xzalloc(sizeof(argv[0]) * cnt);
+        G.argv_from_re_execing = argv = pp = xzalloc(sizeof(argv[0]) * cnt);
         *pp++ = (char *) G.argv0_for_re_execing;
         *pp++ = param_buf;
         for (cur = G.top_var; cur; cur = cur->next) {
@@ -2232,22 +2243,21 @@ static void re_execute_shell(const char *s, int is_heredoc)
          * I conclude it means we don't need to pass active traps here.
          * exec syscall below resets them to SIG_DFL for us.
          */
-        *pp++ = (char *) (is_heredoc ? "-<" : "-c");
+        *pp++ = (char *) "-c";
         *pp++ = (char *) s;
         pp2 = G.global_argv;
         while (*pp2)
                 *pp++ = *pp2++;
         /* *pp = NULL; - is already there */
+        pp = environ;
 
+ do_exec:
         debug_printf_exec("re_execute_shell pid:%d cmd:'%s'\n", getpid(), s);
         sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
-        execve(bb_busybox_exec_path,
-                G.argv_from_re_execing,
-                (is_heredoc ? pp /* points to NULL ptr */ : environ)
-                );
+        execve(bb_busybox_exec_path, argv, pp);
         /* Fallback. Useful for init=/bin/hush usage etc */
-        if (G.argv0_for_re_execing[0] == '/')
-                execv(G.argv0_for_re_execing, G.argv_from_re_execing);
+        if (argv[0][0] == '/')
+                execve(argv[0], argv, pp);
         xfunc_error_retval = 127;
         bb_error_msg_and_die("can't re-execute the shell");
 }
@@ -2281,6 +2291,7 @@ static void setup_heredoc(struct redir_struct *redir)
         }
         len = strlen(heredoc);
 
+        close(redir->rd_fd); /* often saves dup2+close in xmove_fd */
         xpiped_pair(pair);
         xmove_fd(pair.rd, redir->rd_fd);