Update.

	* sysdeps/posix/system.c (do_system): Add support for installation
	of cancellation handlers.
	* sysdeps/unix/sysv/linux/i386/system.c: New file.

	* stdlib/Makefile (tests): Add tst-system.
	* stdlib/tst-system.c: New file.

2 files changed, 79 insertions, 0 deletions

diff --git a/sysdeps/posix/system.c b/sysdeps/posix/system.c
index bca1c2ec3e..08852801a6 100644
--- a/sysdeps/posix/system.c
+++ b/sysdeps/posix/system.c
@@ -112,7 +112,15 @@ do_system (const char *line)
 	}
     }
 
+#ifdef CLEANUP_HANDLER
+  CLEANUP_HANDLER;
+#endif
+
+#ifdef FORK
+  pid = FORK ();
+#else
   pid = __fork ();
+#endif
   if (pid == (pid_t) 0)
     {
       /* Child side.  */
@@ -158,6 +166,10 @@ do_system (const char *line)
 #endif
     }
 
+#ifdef CLEANUP_HANDLER
+  CLEANUP_RESET;
+#endif
+
   save = errno;
   DO_LOCK ();
   if ((SUB_REF () == 0
diff --git a/sysdeps/unix/sysv/linux/i386/system.c b/sysdeps/unix/sysv/linux/i386/system.c
new file mode 100644
index 0000000000..1107fd6668
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/i386/system.c
@@ -0,0 +1,67 @@
+/* Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <sched.h>
+#include <signal.h>
+#include <sysdep.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <bits/libc-lock.h>
+
+/* We have to and actually can handle cancelable system().  The big
+   problem: we have to kill the child process if necessary.  To do
+   this a cleanup handler has to be registered and is has to be able
+   to find the PID of the child.  The main problem is to reliable have
+   the PID when needed.  It is not necessary for the parent thread to
+   return.  It might still be in the kernel when the cancellation
+   request comes.  Therefore we have to use the clone() calls ability
+   to have the kernel write the PID into the user-level variable.  */
+#define FORK() \
+  INLINE_SYSCALL (clone, 3, CLONE_PARENT_SETTID | SIGCHLD, 0, &pid)
+
+static void cancel_handler (void *arg);
+
+#define CLEANUP_HANDLER \
+  __libc_cleanup_region_start (0, cancel_handler, &pid)
+
+#define CLEANUP_RESET \
+  __libc_cleanup_region_end (0)
+
+
+/* Linux has waitpid(), so override the generic unix version.  */
+#include <sysdeps/posix/system.c>
+
+
+/* The cancellation handler.  */
+static void
+cancel_handler (void *arg)
+{
+  __kill (SIGKILL, *(pid_t *) arg);
+
+  TEMP_FAILURE_RETRY (waitpid (*(pid_t *) arg, NULL, 0));
+
+  DO_LOCK ();
+
+  if (SUB_REF () == 0)
+    {
+      (void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);
+      (void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);
+    }
+
+  DO_UNLOCK ();
+}