[patch] Fix `shell' command for async (PR 12850)

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

this was completely debugged by Pedro so just wrote it and posted.
I mentioned+filed this problem at:
	Re: Sending signal to inferior program.
	http://sourceware.org/ml/gdb/2011-06/msg00036.html

procfs.c contains such fix but #if0-ed, left it as is:
    /* FIXME: should we use waitpid to make sure we get the right event?
       Should we check the returned event?  */
    {
#if 0
      int status, ret;

      ret = waitpid (pi->pid, &status, 0);
#else
      wait (NULL);
#endif

proc-api.c also contains dangerous wait() call but both are for procfs
platforms.

No regressions on {x86_64,x86_64-m32,i686}-fedora15-linux-gnu.  I have not
regression tested the modified PPC* file.  The testcase can have false PASS
(with buggy GDB) but I do not see how to avoid it.

I will check it in with no comments.


Thanks,
Jan


gdb/
2011-06-07  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* cli/cli-cmds.c (shell_escape): Use waitpid.
	* rs6000-nat.c (exec_one_dummy_insn): Likewise.

gdb/testsuite/
2011-06-07  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.base/async-shell.c: New file.
	* gdb.base/async-shell.exp: New file.

--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -750,7 +750,7 @@ shell_escape (char *arg, int from_tty)
     }
 
   if (pid != -1)
-    while ((rc = wait (&status)) != pid && rc != -1)
+    while ((rc = waitpid (pid, &status, 0)) != pid && rc != -1)
       ;
   else
     error (_("Fork failed"));
--- a/gdb/rs6000-nat.c
+++ b/gdb/rs6000-nat.c
@@ -614,7 +614,7 @@ exec_one_dummy_insn (struct regcache *regcache)
 
   do
     {
-      pid = wait (&status);
+      pid = waitpid (PIDGET (inferior_ptid), &status, 0);
     }
   while (pid != PIDGET (inferior_ptid));
 
--- /dev/null
+++ b/gdb/testsuite/gdb.base/async-shell.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2011 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int
+main (void)
+{
+  return sleep (600);
+}
--- /dev/null
+++ b/gdb/testsuite/gdb.base/async-shell.exp
@@ -0,0 +1,42 @@
+# Copyright (C) 2011 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+set testfile async-shell
+if { [prepare_for_testing ${testfile}.exp ${testfile}] } {
+    return -1
+}
+
+gdb_test_no_output "set target-async on "
+gdb_test_no_output "set non-stop on"
+gdb_test "run &" "Starting program: \[^\r\n\]*"
+
+# `sleep 5' here would workaround the bug, do not sleep here.
+# "shell" could eat waitpid event from the asynchronous inferior process.
+
+gdb_test "shell echo foo" "foo"
+
+set test "interrupt"
+gdb_test_multiple $test $test {
+    -re "interrupt\r\n$gdb_prompt " {
+	pass $test
+    }
+}
+
+set test "process stopped"
+gdb_test_multiple "" $test {
+    -re "\r\n\\\[process \[0-9\]+\\\] #1 stopped\\\.\r\n" {
+	pass $test
+    }
+}