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[PATCH] getpid/vfork/raise fix


On Tue, Mar 09, 2004 at 02:01:21PM +0100, Andreas Schwab wrote:
> Ulrich Drepper <drepper@redhat.com> writes:
> 
> > Anyway, for the getpid handling, the other archs need to be handled,
> > too.  The x86/x86-64 changes are kept small, I envision this is the
> > model for the other archs, too.
> 
> Here's the same for ia64.
> 
> Andreas.
> 
> 2004-03-09  Andreas Schwab  <schwab@suse.de>
> 
> 	* sysdeps/ia64/tcb-offsets.sym: Add PID.
> 	* sysdeps/unix/sysv/linux/ia64/vfork.S: New file.

Please wait a little bit.

The following patch changes vfork/raise so that tst-vfork2 included below
succeeds.  raise is async-safe and thus it certainly should work any time,
even while executing a vfork.
The raise.c changes at least on i386/x86-64 don't create any additional
instructions, just change a testl into andl.
Also, it changes libpthread.so's vfork to handle getpid () as well
(there SAVE_PID can be simpler, since THREAD_SELF->pid certainly will
be non-zero).

Also, x86-64 did not build at all:
In file included from sysdeps/unix/sysv/linux/x86_64/vfork.S:35,
                 from sysdeps/unix/sysv/linux/x86_64/vfork.S:35,
...
                 from sysdeps/unix/sysv/linux/x86_64/vfork.S:35,
                 from ../nptl/sysdeps/unix/sysv/linux/x86_64/pt-vfork.S:1:
sysdeps/unix/sysv/linux/x86_64/vfork.S:19:10: #include nested too deeply
sysdeps/unix/sysv/linux/x86_64/vfork.S:35:10: #include nested too deeply
make[2]: *** [/usr/src/libc/obj/nptl/pt-vfork.o] Error 1
because <sysdeps/unix/sysv/linux/x86_64/vfork.S> include in
nptl/sysdeps/unix/sysv/linux/x86_64/pt-vfork.S included
nptl/sysdeps/unix/sysv/linux/x86_64/vfork.S and so did that include
in nptl/sysdeps/unix/sysv/linux/x86_64/vfork.S.

2004-02-09  Jakub Jelinek  <jakub@redhat.com>

	* posix/Makefile (tests): Add tst-vfork2.
	* posix/tst-vfork1.c (do_test): Fix comment.
	* posix/tst-vfork2.c: New test.
nptl/
	* sysdeps/unix/sysv/linux/i386/vfork.S (SAVE_PID): Negate PID
	if non-zero and set to INT_MIN if zero.
	* sysdeps/unix/sysv/linux/x86_64/vfork.S (SAVE_PID): Likewise.
	* sysdeps/unix/sysv/linux/i386/pt-vfork.S: Include tcb-offsets.h.
	(SAVE_PID, RESTORE_PID): Define.
	(__vfork): Use it.
	* sysdeps/unix/sysv/linux/x86_64/pt-vfork.S: Include tcb-offsets.h.
	Use relative path to avoid including NPTL i386/vfork.S.
	(SAVE_PID, RESTORE_PID): Define.
	* sysdeps/unix/sysv/linux/raise.c: Include limits.h.
	(raise): Handle THREAD_SELF->pid INT_MIN the same as 0.
	* Makefile (tests): Add tst-vfork1, tst-vfork2, tst-vfork1x and
	tst-vfork2x.
	(tests-reverse): Add tst-vfork1x and tst-vfork2x.
	* tst-vfork1.c: New test.
	* tst-vfork2.c: New test.
	* tst-vfork1x.c: New test.
	* tst-vfork2x.c: New test.

--- libc/nptl/sysdeps/unix/sysv/linux/i386/pt-vfork.S.jj	2004-01-12 11:06:56.000000000 +0100
+++ libc/nptl/sysdeps/unix/sysv/linux/i386/pt-vfork.S	2004-03-09 14:47:21.957260874 +0100
@@ -1,4 +1,4 @@
-/* Copyright (C) 1999, 2002 Free Software Foundation, Inc.
+/* Copyright (C) 1999, 2002, 2004 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Andreas Schwab <schwab@gnu.org>.
 
@@ -21,6 +21,21 @@
 #define _ERRNO_H	1
 #include <bits/errno.h>
 #include <kernel-features.h>
+#include <tcb-offsets.h>
+
+/* Save the PID value.  */
+#define SAVE_PID \
+	movl	%gs:PID, %edx; 						      \
+	movl	%edx, %eax;						      \
+	negl	%eax;							      \
+	movl	%eax, %gs:PID
+
+/* Restore the old PID value in the parent.  */
+#define RESTORE_PID \
+	testl	%eax, %eax;						      \
+	je	1f;							      \
+	movl	%edx, %gs:PID;						      \
+1:
 
 /* Clone the calling process, but without copying the whole address space.
    The calling process is suspended until the new process exits or is
@@ -31,10 +46,14 @@ ENTRY (__vfork)
 	/* Pop the return PC value into ECX.  */
 	popl	%ecx
 
+	SAVE_PID
+
 	/* Stuff the syscall number in EAX and enter into the kernel.  */
 	movl	$SYS_ify (vfork), %eax
 	int	$0x80
 
+	RESTORE_PID
+
 	/* Jump to the return PC.  Don't jump directly since this
 	   disturbs the branch target cache.  Instead push the return
 	   address back on the stack.  */
--- libc/nptl/sysdeps/unix/sysv/linux/i386/vfork.S.jj	2004-03-09 07:14:20.000000000 +0100
+++ libc/nptl/sysdeps/unix/sysv/linux/i386/vfork.S	2004-03-09 13:56:18.874763704 +0100
@@ -21,9 +21,13 @@
 /* Save the PID value.  */
 #define SAVE_PID \
 	movl	%gs:PID, %edx; 						      \
-	movl	$-1, %gs:PID
+	movl	%edx, %eax;						      \
+	negl	%eax;							      \
+	jne	1f;							      \
+	movl	$0x80000000, %eax;					      \
+1:	movl	%eax, %gs:PID
 
-/* Restore the old PID value in the parent.  In the child store 0.  */
+/* Restore the old PID value in the parent.  */
 #define RESTORE_PID \
 	testl	%eax, %eax;						      \
 	je	1f;							      \
--- libc/nptl/sysdeps/unix/sysv/linux/raise.c.jj	2003-12-29 15:01:27.000000000 +0100
+++ libc/nptl/sysdeps/unix/sysv/linux/raise.c	2004-03-09 11:36:05.351402845 +0100
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
 
@@ -18,6 +18,7 @@
    02111-1307 USA.  */
 
 #include <errno.h>
+#include <limits.h>
 #include <signal.h>
 #include <sysdep.h>
 #include <nptl/pthreadP.h>
@@ -53,10 +54,10 @@ raise (sig)
 #if __ASSUME_TGKILL || defined __NR_tgkill
   else
     /* raise is an async-safe function.  It could be called while the
-       fork function temporarily invalidated the PID field.  Adjust for
+       fork/vfork function temporarily invalidated the PID field.  Adjust for
        that.  */
     if (__builtin_expect (pid <= 0, 0))
-      pid = pid == 0 ? selftid : -pid;
+      pid = (pid & INT_MAX) == 0 ? selftid : -pid;
 #endif
 
 #if __ASSUME_TGKILL
--- libc/nptl/sysdeps/unix/sysv/linux/x86_64/pt-vfork.S.jj	2002-11-28 09:34:22.000000000 +0100
+++ libc/nptl/sysdeps/unix/sysv/linux/x86_64/pt-vfork.S	2004-03-09 14:44:53.636925647 +0100
@@ -1 +1,33 @@
-#include <sysdeps/unix/sysv/linux/x86_64/vfork.S>
+/* Copyright (C) 2004 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 <tcb-offsets.h>
+
+#define SAVE_PID \
+	movl	%fs:PID, %esi;						      \
+	movl	%esi, %edx;						      \
+	negl	%edx;							      \
+	movl	%edx, %fs:PID
+
+#define RESTORE_PID \
+	testq	%rax, %rax;						      \
+	je	1f;							      \
+	movl	%esi, %fs:PID;						      \
+1:
+
+#include <../../../../../../sysdeps/unix/sysv/linux/x86_64/vfork.S>
--- libc/nptl/sysdeps/unix/sysv/linux/x86_64/vfork.S.jj	2004-03-09 07:28:23.000000000 +0100
+++ libc/nptl/sysdeps/unix/sysv/linux/x86_64/vfork.S	2004-03-09 13:40:28.713295993 +0100
@@ -20,7 +20,11 @@
 
 #define SAVE_PID \
 	movl	%fs:PID, %esi;						      \
-	movl	$-1, %fs:PID
+	movl	$0x80000000, %ecx;					      \
+	movl	%esi, %edx;						      \
+	negl	%edx;							      \
+	cmove	%ecx, %edx;						      \
+	movl	%edx, %fs:PID
 
 #define RESTORE_PID \
 	testq	%rax, %rax;						      \
--- libc/nptl/Makefile.jj	2004-03-03 18:28:59.000000000 +0100
+++ libc/nptl/Makefile	2004-03-09 14:36:30.367401555 +0100
@@ -237,7 +237,8 @@ tests = tst-attr1 tst-attr2 tst-attr3 \
 	tst-context1 \
 	tst-sched1 \
 	tst-backtrace1 \
-	tst-oddstacklimit
+	tst-oddstacklimit \
+	tst-vfork1 tst-vfork2 tst-vfork1x tst-vfork2x
 
 # Files which must not be linked with libpthread.
 tests-nolibpthread = tst-unload
@@ -337,7 +338,7 @@ ifeq ($(build-static),yes)
 tests-static += tst-locale1 tst-locale2
 endif
 # These tests are linked with libc before libpthread
-tests-reverse += tst-cancel5 tst-cancel23
+tests-reverse += tst-cancel5 tst-cancel23 tst-vfork1x tst-vfork2x
 
 include ../Rules
 
--- libc/nptl/tst-vfork1.c.jj	2004-03-09 14:34:04.945544474 +0100
+++ libc/nptl/tst-vfork1.c	2004-03-09 14:33:57.961799957 +0100
@@ -0,0 +1 @@
+#include <posix/tst-vfork1.c>
--- libc/nptl/tst-vfork2.c.jj	2004-03-09 14:34:12.492187796 +0100
+++ libc/nptl/tst-vfork2.c	2004-03-09 14:34:16.293504425 +0100
@@ -0,0 +1 @@
+#include <posix/tst-vfork2.c>
--- libc/nptl/tst-vfork1x.c.jj	2004-03-09 14:34:04.000000000 +0100
+++ libc/nptl/tst-vfork1x.c	2004-03-09 14:33:57.000000000 +0100
@@ -0,0 +1 @@
+#include <posix/tst-vfork1.c>
--- libc/nptl/tst-vfork2x.c.jj	2004-03-09 14:35:10.298795753 +0100
+++ libc/nptl/tst-vfork2x.c	2004-03-09 14:35:00.748512634 +0100
@@ -0,0 +1 @@
+#include <posix/tst-vfork2.c>
--- libc/posix/tst-vfork2.c.jj	2004-03-09 13:18:30.939786289 +0100
+++ libc/posix/tst-vfork2.c	2004-03-09 13:32:32.517759464 +0100
@@ -0,0 +1,199 @@
+/* Test for chmod functions.
+   Copyright (C) 2004 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2004.
+
+   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 <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+int raise_fail;
+
+static void
+alrm (int sig)
+{
+  if (raise (SIGUSR1) < 0)
+    raise_fail = 1;
+}
+
+/* This test relies on non-POSIX functionality since the child
+   processes call write, nanosleep and getpid.  */
+static int
+do_test (void)
+{
+  int result = 0;
+  int fd[2];
+
+  signal (SIGUSR1, SIG_IGN);
+
+  struct sigaction sa;
+  sa.sa_handler = alrm;
+  sigemptyset (&sa.sa_mask);
+  sa.sa_flags = 0;
+  if (sigaction (SIGALRM, &sa, NULL) < 0)
+    {
+      puts ("couldn't set up SIGALRM handler");
+      return 1;
+    }
+
+  if (pipe (fd) == -1)
+    {
+      puts ("pipe failed");
+      return 1;
+    }
+
+  struct itimerval it;
+  it.it_value.tv_sec = 0;
+  it.it_value.tv_usec = 200 * 1000;
+  it.it_interval = it.it_value;
+  if (setitimer (ITIMER_REAL, &it, NULL) < 0)
+    {
+      puts ("couldn't set up timer");
+      return 1;
+    }
+
+  /* First vfork() without previous getpid().  */
+  pid_t p1;
+  if ((p1 = vfork ()) == 0)
+    {
+      pid_t p = getpid ();
+
+      struct timespec ts;
+      ts.tv_sec = 1;
+      ts.tv_nsec = 0;
+      TEMP_FAILURE_RETRY (nanosleep (&ts, &ts));
+      _exit (TEMP_FAILURE_RETRY (write (fd[1], &p, sizeof (p))) != sizeof (p));
+    }
+  else if (p1 == -1)
+    {
+      puts ("1st vfork failed");
+      result = 1;
+    }
+
+  memset (&it, 0, sizeof (it));
+  setitimer (ITIMER_REAL, &it, NULL);
+
+  pid_t p2 = 0;
+  if (TEMP_FAILURE_RETRY (read (fd[0], &p2, sizeof (pid_t))) != sizeof (pid_t))
+    {
+      puts ("1st read failed");
+      result = 1;
+    }
+  int r;
+  if (TEMP_FAILURE_RETRY (waitpid (p1, &r, 0)) != p1)
+    {
+      puts ("1st waitpid failed");
+      result = 1;
+    }
+  else if (r != 0)
+    {
+      puts ("write in 1st child failed");
+      result = 1;
+    }
+
+  /* Main process' ID.  */
+  pid_t p0 = getpid ();
+
+  /* vfork() again, but after a getpid() in the main process.  */
+  pid_t p3;
+  if ((p3 = vfork ()) == 0)
+    {
+      pid_t p = getpid ();
+      _exit (TEMP_FAILURE_RETRY (write (fd[1], &p, sizeof (p))) != sizeof (p));
+    }
+  else if (p1 == -1)
+    {
+      puts ("2nd vfork failed");
+      result = 1;
+    }
+
+  pid_t p4;
+  if (TEMP_FAILURE_RETRY (read (fd[0], &p4, sizeof (pid_t))) != sizeof (pid_t))
+    {
+      puts ("2nd read failed");
+      result = 1;
+    }
+  if (TEMP_FAILURE_RETRY (waitpid (p3, &r, 0)) != p3)
+    {
+      puts ("2nd waitpid failed");
+      result = 1;
+    }
+  else if (r != 0)
+    {
+      puts ("write in 2nd child failed");
+      result = 1;
+    }
+
+  /* And getpid in the main process again.  */
+  pid_t p5 = getpid ();
+
+  /* Analysis of the results.  */
+  if (p0 != p5)
+    {
+      printf ("p0(%ld) != p5(%ld)\n", (long int) p0, (long int) p5);
+      result = 1;
+    }
+
+  if (p0 == p1)
+    {
+      printf ("p0(%ld) == p1(%ld)\n", (long int) p0, (long int) p1);
+      result = 1;
+    }
+
+  if (p1 != p2)
+    {
+      printf ("p1(%ld) != p2(%ld)\n", (long int) p1, (long int) p2);
+      result = 1;
+    }
+
+  if (p0 == p3)
+    {
+      printf ("p0(%ld) == p3(%ld)\n", (long int) p0, (long int) p3);
+      result = 1;
+    }
+
+  if (p3 != p4)
+    {
+      printf ("p3(%ld) != p4(%ld)\n", (long int) p3, (long int) p4);
+      result = 1;
+    }
+
+  close (fd[0]);
+  close (fd[1]);
+
+  if (raise_fail)
+    {
+      puts ("raise failed");
+      result = 1;
+    }
+
+  if (result == 0)
+    puts ("All OK");
+
+  return result;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
--- libc/posix/tst-vfork1.c.jj	2004-03-09 09:49:09.000000000 +0100
+++ libc/posix/tst-vfork1.c	2004-03-09 11:33:26.138172512 +0100
@@ -26,7 +26,7 @@
 #include <sys/wait.h>
 
 /* This test relies on non-POSIX functionality since the child
-   processes call write.  */
+   processes call write and getpid.  */
 static int
 do_test (void)
 {
--- libc/posix/Makefile.jj	2004-03-09 10:58:14.000000000 +0100
+++ libc/posix/Makefile	2004-03-09 13:35:55.967245760 +0100
@@ -81,7 +81,7 @@ tests		:= tstgetopt testfnm runtests run
 		   bug-regex17 bug-regex18 bug-regex19 bug-regex20 \
 		   bug-regex21 bug-regex22 bug-regex23 tst-nice tst-nanosleep \
 		   transbug tst-rxspencer tst-pcre tst-boost \
-		   bug-ga1 tst-vfork1
+		   bug-ga1 tst-vfork1 tst-vfork2
 xtests		:= bug-ga2
 ifeq (yes,$(build-shared))
 test-srcs	:= globtest


	Jakub


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