bash-custom-action/bash-4.1-pipe.dif

--- execute_cmd.c
+++ execute_cmd.c	2010-06-24 09:18:46.858925084 +0200
@@ -1525,7 +1525,7 @@ static struct cpelement *cpl_search __P(
 static struct cpelement *cpl_searchbyname __P((char *));
 static void cpl_prune __P((void));
 
-Coproc sh_coproc = { 0, NO_PID, -1, -1, 0, 0 };
+Coproc sh_coproc = { 0, NO_PID, -1, -1, 0, 0, 0, 0 };
 
 cplist_t coproc_list = {0, 0, 0};
 
@@ -2047,13 +2047,19 @@ execute_coproc (command, pipe_in, pipe_o
 }
 #endif
 
+static void restore_stdin(int lstdin)
+{
+  dup2(lstdin, 0);
+  close(lstdin);
+}
+
 static int
 execute_pipeline (command, asynchronous, pipe_in, pipe_out, fds_to_close)
      COMMAND *command;
      int asynchronous, pipe_in, pipe_out;
      struct fd_bitmap *fds_to_close;
 {
-  int prev, fildes[2], new_bitmap_size, dummyfd, ignore_return, exec_result;
+  int lstdin, prev, fildes[2], new_bitmap_size, dummyfd, ignore_return, exec_result;
   COMMAND *cmd;
   struct fd_bitmap *fd_bitmap;
 
@@ -2148,11 +2154,37 @@ execute_pipeline (command, asynchronous,
   /* Now execute the rightmost command in the pipeline.  */
   if (ignore_return && cmd)
     cmd->flags |= CMD_IGNORE_RETURN;
+
+  begin_unwind_frame ("pipe-file-descriptors");
+  lstdin = -1;
+  if (!asynchronous && pipe_out == NO_PIPE && prev > 0)
+    {
+      lstdin = move_to_high_fd(0, 0, 255);
+      if (lstdin > 0)
+	{
+	  dup2(prev, 0);
+	  close(prev);
+	  prev = NO_PIPE;
+	  stop_pipeline (0, (COMMAND *)NULL);
+	  add_unwind_protect (restore_stdin, lstdin);
+	}
+    }
+  if (prev >= 0)
+    add_unwind_protect (close, prev);
+
   exec_result = execute_command_internal (cmd, asynchronous, prev, pipe_out, fds_to_close);
 
+  if (lstdin > 0)
+    {
+      dup2(lstdin, 0);
+      close(lstdin);
+    }
+
   if (prev >= 0)
     close (prev);
 
+  discard_unwind_frame ("pipe-file-descriptors");
+
 #if defined (JOB_CONTROL)
   UNBLOCK_CHILD (oset);
 #endif