[PATCH] Additional setcontext(), etc. POSIX conformance tests

["Maciej W. Rozycki" <macro at codesourcery dot com>]

Hello,

 While developing the implementation of the setcontext(), etc. API for the 
MIPS platform earlier this year, I used these additional tests to verify 
POSIX conformance (cf. 
http://www.opengroup.org/onlinepubs/009695399/functions/setcontext.html).  
Their purpose is as follows:

- tst-makecontext3.c -- verify that for ABIs that use a mixed 
  register/stack argument passing convention arguments are placed in their 
  designated registers and stack slots correctly -- the existing tests 
  would not hit the argument register limit for some ABIs, such as MIPS 
  n64 and n32 ABIs that define eight argument registers,

- tst-sigcontext.c -- verify that a user context obtained from a signal 
  handler can be used with setcontext(), etc.

 I've thought it might be worth sharing these tests with the community so 
that developers can readily verify the respective implementations for 
platforms they are interested in and do not have to reinvent the wheel.

2009-12-15  Maciej W. Rozycki  <macro@codesourcery.com>

	* stdlib/tst-makecontext3.c: New test.
	* stdlib/tst-sigcontext.c: Likewise.
	* stdlib/Makefile (tests): Add them.

	* stdlib/tst-setcontext.c (check_called): Fix a typo.

 Please apply.

  Maciej

glibc-2.11.90-20091215-tst-ucontext-3.patch
diff --git a/stdlib/Makefile b/stdlib/Makefile
index d361dd8..882302f 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -70,7 +70,8 @@ tests		:= tst-strtol tst-strtod testmb testrand testsort testdiv   \
 		   test-a64l tst-qsort tst-system testmb2 bug-strtod2	    \
 		   tst-atof1 tst-atof2 tst-strtod2 tst-strtod3 tst-rand48-2 \
 		   tst-makecontext tst-strtod4 tst-strtod5 tst-qsort2	    \
-		   tst-makecontext2 tst-strtod6 tst-unsetenv1
+		   tst-makecontext2 tst-strtod6 tst-unsetenv1		    \
+		   tst-makecontext3 tst-sigcontext
 
 include ../Makeconfig
 
diff --git a/stdlib/tst-makecontext3.c b/stdlib/tst-makecontext3.c
new file mode 100644
index 0000000..f127c6a
--- /dev/null
+++ b/stdlib/tst-makecontext3.c
@@ -0,0 +1,217 @@
+/* Copyright (C) 2001,2002,2004,2006,2009 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, 51 Franklin Street - Fifth Floor, Boston, MA
+   02110-1301, USA.  */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+static ucontext_t ctx[3];
+
+static int was_in_f1;
+static int was_in_f2;
+
+static char st2[32768];
+
+static volatile int flag;
+
+static void
+f1 (int a00, int a01, int a02, int a03, int a04, int a05, int a06, int a07,
+    int a08, int a09, int a10, int a11, int a12, int a13, int a14, int a15,
+    int a16, int a17, int a18, int a19, int a20, int a21, int a22, int a23,
+    int a24, int a25, int a26, int a27, int a28, int a29, int a30, int a31,
+    int a32)
+{
+  printf ("start f1(a00=%08x,a01=%08x,a02=%08x,a03=%08x,\n"
+	  "         a04=%08x,a05=%08x,a06=%08x,a07=%08x,\n"
+	  "         a08=%08x,a09=%08x,a10=%08x,a11=%08x,\n"
+	  "         a12=%08x,a13=%08x,a14=%08x,a15=%08x,\n"
+	  "         a16=%08x,a17=%08x,a18=%08x,a19=%08x,\n"
+	  "         a20=%08x,a21=%08x,a22=%08x,a23=%08x,\n"
+	  "         a24=%08x,a25=%08x,a26=%08x,a27=%08x,\n"
+	  "         a28=%08x,a29=%08x,a30=%08x,a31=%08x,\n"
+	  "         a32=%08x) [%d]\n",
+	  a00, a01, a02, a03, a04, a05, a06, a07,
+	  a08, a09, a10, a11, a12, a13, a14, a15,
+	  a16, a17, a18, a19, a20, a21, a22, a23,
+	  a24, a25, a26, a27, a28, a29, a30, a31,
+	  a32, flag);
+
+  if (a00 != (0x00000001 << flag) || a01 != (0x00000004 << flag)
+      || a02 != (0x00000012 << flag) || a03 != (0x00000048 << flag)
+      || a04 != (0x00000123 << flag) || a05 != (0x0000048d << flag)
+      || a06 != (0x00001234 << flag) || a07 != (0x000048d1 << flag)
+      || a08 != (0x00012345 << flag) || a09 != (0x00048d15 << flag)
+      || a10 != (0x00123456 << flag) || a11 != (0x0048d159 << flag)
+      || a12 != (0x01234567 << flag) || a13 != (0x048d159e << flag)
+      || a14 != (0x12345678 << flag) || a15 != (0x48d159e2 << flag)
+      || a16 != (0x23456789 << flag) || a17 != (0x8d159e26 << flag)
+      || a18 != (0x3456789a << flag) || a19 != (0xd159e26a << flag)
+      || a20 != (0x456789ab << flag) || a21 != (0x159e26af << flag)
+      || a22 != (0x56789abc << flag) || a23 != (0x59e26af3 << flag)
+      || a24 != (0x6789abcd << flag) || a25 != (0x9e26af37 << flag)
+      || a26 != (0x789abcde << flag) || a27 != (0xe26af37b << flag)
+      || a28 != (0x89abcdef << flag) || a29 != (0x26af37bc << flag)
+      || a30 != (0x9abcdef0 << flag) || a31 != (0x6af37bc3 << flag)
+      || a32 != (0xabcdef0f << flag))
+    {
+      puts ("arg mismatch");
+      exit (-1);
+    }
+
+  if (flag && swapcontext (&ctx[1], &ctx[2]) != 0)
+    {
+      printf ("%s: swapcontext: %m\n", __FUNCTION__);
+      exit (1);
+    }
+  printf ("finish f1 [%d]\n", flag);
+  flag++;
+  was_in_f1++;
+}
+
+static void
+f2 (void)
+{
+  puts ("start f2");
+  if (swapcontext (&ctx[2], &ctx[1]) != 0)
+    {
+      printf ("%s: swapcontext: %m\n", __FUNCTION__);
+      exit (1);
+    }
+  puts ("finish f2");
+  was_in_f2 = 1;
+}
+
+volatile int global;
+
+
+static int back_in_main;
+
+
+static void
+check_called (void)
+{
+  if (back_in_main == 0)
+    {
+      puts ("program did not reach main again");
+      _exit (1);
+    }
+}
+
+
+int
+main (void)
+{
+  atexit (check_called);
+
+  char st1[32768];
+
+  puts ("making contexts");
+  if (getcontext (&ctx[0]) != 0)
+    {
+      if (errno == ENOSYS)
+	{
+	  back_in_main = 1;
+	  exit (0);
+	}
+
+      printf ("%s: getcontext: %m\n", __FUNCTION__);
+      exit (1);
+    }
+
+  ctx[1] = ctx[0];
+  ctx[1].uc_stack.ss_sp = st1;
+  ctx[1].uc_stack.ss_size = sizeof st1;
+  ctx[1].uc_link = &ctx[0];
+  {
+    ucontext_t tempctx = ctx[1];
+    makecontext (&ctx[1], (void (*) (void)) f1, 33,
+		 0x00000001 << flag, 0x00000004 << flag,
+		 0x00000012 << flag, 0x00000048 << flag,
+		 0x00000123 << flag, 0x0000048d << flag,
+		 0x00001234 << flag, 0x000048d1 << flag,
+		 0x00012345 << flag, 0x00048d15 << flag,
+		 0x00123456 << flag, 0x0048d159 << flag,
+		 0x01234567 << flag, 0x048d159e << flag,
+		 0x12345678 << flag, 0x48d159e2 << flag,
+		 0x23456789 << flag, 0x8d159e26 << flag,
+		 0x3456789a << flag, 0xd159e26a << flag,
+		 0x456789ab << flag, 0x159e26af << flag,
+		 0x56789abc << flag, 0x59e26af3 << flag,
+		 0x6789abcd << flag, 0x9e26af37 << flag,
+		 0x789abcde << flag, 0xe26af37b << flag,
+		 0x89abcdef << flag, 0x26af37bc << flag,
+		 0x9abcdef0 << flag, 0x6af37bc3 << flag,
+		 0xabcdef0f << flag);
+
+    /* Without this check, a stub makecontext can make us spin forever.  */
+    if (memcmp (&tempctx, &ctx[1], sizeof ctx[1]) == 0)
+      {
+	puts ("makecontext was a no-op, presuming not implemented");
+	return 0;
+      }
+  }
+
+  /* Play some tricks with this context.  */
+  if (++global == 1)
+    if (setcontext (&ctx[1]) != 0)
+      {
+	printf ("%s: setcontext: %m\n", __FUNCTION__);
+	exit (1);
+      }
+  if (global != 2)
+    {
+      printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
+      exit (1);
+    }
+
+  if (getcontext (&ctx[2]) != 0)
+    {
+      printf ("%s: second getcontext: %m\n", __FUNCTION__);
+      exit (1);
+    }
+  ctx[2].uc_stack.ss_sp = st2;
+  ctx[2].uc_stack.ss_size = sizeof st2;
+  ctx[2].uc_link = &ctx[1];
+  makecontext (&ctx[2], f2, 0);
+
+  puts ("swapping contexts");
+  if (swapcontext (&ctx[0], &ctx[2]) != 0)
+    {
+      printf ("%s: swapcontext: %m\n", __FUNCTION__);
+      exit (1);
+    }
+  puts ("back at main program");
+  back_in_main = 1;
+
+  if (was_in_f1 < 2)
+    {
+      puts ("didn't reach f1 twice");
+      exit (1);
+    }
+  if (was_in_f2 == 0)
+    {
+      puts ("didn't reach f2");
+      exit (1);
+    }
+
+  puts ("test succeeded");
+  return 0;
+}
diff --git a/stdlib/tst-setcontext.c b/stdlib/tst-setcontext.c
index 51296f7..9a6d79b 100644
--- a/stdlib/tst-setcontext.c
+++ b/stdlib/tst-setcontext.c
@@ -133,7 +133,7 @@ check_called (void)
 {
   if (back_in_main == 0)
     {
-      puts ("program did no reach main again");
+      puts ("program did not reach main again");
       _exit (1);
     }
 }
diff --git a/stdlib/tst-sigcontext.c b/stdlib/tst-sigcontext.c
new file mode 100644
index 0000000..45b1a06
--- /dev/null
+++ b/stdlib/tst-sigcontext.c
@@ -0,0 +1,312 @@
+/* Copyright (C) 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Maciej W. Rozycki <macro@codesourcery.com>.
+
+   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, 51 Franklin Street - Fifth Floor, Boston, MA
+   02110-1301, USA.  */
+
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+static volatile ucontext_t ctx[3];
+static volatile int flags[3];
+static volatile int oflag;
+static volatile int flag;
+
+static volatile int sig_errno_set;
+static volatile int sig_errno;
+static volatile int sig_ready;
+
+static int was_in_f1;
+static int was_in_f2;
+
+static char st2[32768];
+
+static long long int max;
+static volatile long long int count;
+
+/* These have to be run with the caller's frame.  */
+static inline int sig_getcontext (int) __attribute__ ((always_inline));
+static inline int sig_swapcontext (int, int) __attribute__ ((always_inline));
+
+static void
+sig_gethandler (int signo, siginfo_t *info, void *context)
+{
+  ucontext_t *ucp = context;
+
+  if (! sig_ready)
+    {
+      alarm (1);
+      return;
+    }
+
+  ctx[flag] = *ucp;
+  flags[flag] = 1;
+
+  sig_errno_set = 1;
+  sig_errno = 0;
+}
+
+static void
+sig_swaphandler (int signo, siginfo_t *info, void *context)
+{
+  ucontext_t *oucp = context;
+  ucontext_t *ucp = (ucontext_t *) (ctx + flag);
+
+  if (! sig_ready)
+    {
+      alarm (1);
+      return;
+    }
+
+  ctx[oflag] = *oucp;
+  flags[oflag] = 1;
+
+  sig_errno_set = 1;
+  sig_errno = setcontext (ucp);
+}
+
+static int
+sig_getcontext (int uci)
+{
+  struct sigaction sa;
+
+  sigemptyset (&sa.sa_mask);
+  sa.sa_flags = SA_SIGINFO;
+  sa.sa_sigaction = sig_gethandler;
+  if (sigaction (SIGALRM, &sa, NULL) < 0)
+    {
+      printf ("%s: sigaction ALRM failed: %m\n", __FUNCTION__);
+      exit (1);
+    }
+
+  flag = uci;
+  sig_errno_set = 0;
+  sig_ready = 0;
+  alarm (1);
+
+  /* Need to get the signal in this frame.  */
+  sig_ready = 1;
+  for (count = max; count > 0; count--)
+    if (sig_errno_set)
+      break;
+
+  if (! sig_errno_set)
+    {
+      printf ("%s: ALRM signal not received\n", __FUNCTION__);
+      exit (1);
+    }
+
+  return 0;
+}
+
+static int
+sig_swapcontext (int ouci, int uci)
+{
+  struct sigaction sa;
+
+  sigemptyset (&sa.sa_mask);
+  sa.sa_flags = SA_SIGINFO;
+  sa.sa_sigaction = sig_swaphandler;
+  if (sigaction (SIGALRM, &sa, NULL) < 0)
+    {
+      printf ("%s: sigaction ALRM failed: %m\n", __FUNCTION__);
+      exit (1);
+    }
+
+  flag = uci;
+  oflag = ouci;
+  sig_errno_set = 0;
+  sig_ready = 0;
+  alarm (1);
+
+  /* Need to get the signal in this frame.  */
+  sig_ready = 1;
+  for (count = max; count > 0; count--)
+    if (sig_errno_set)
+      break;
+
+  if (! sig_errno_set)
+    {
+      printf ("%s: ALRM signal not received\n", __FUNCTION__);
+      exit (1);
+    }
+
+  return sig_errno;
+}
+
+
+static void
+f1 (int a0, int a1, int a2, int a3)
+{
+  int status;
+
+  printf ("start f1(a0=%x,a1=%x,a2=%x,a3=%x)\n", a0, a1, a2, a3);
+
+  if (a0 != 1 || a1 != 2 || a2 != 3 || a3 != -4)
+    {
+      puts ("arg mismatch");
+      exit (-1);
+    }
+
+  status = sig_swapcontext (1, 2);
+  if (status != 0)
+    {
+      printf ("%s: swapping contexts failed: %s\n",
+	      __FUNCTION__, strerror (status));
+      exit (1);
+    }
+  puts ("finish f1");
+  was_in_f1 = 1;
+}
+
+static void
+f2 (void)
+{
+  int status;
+
+  puts ("start f2");
+
+  status = sig_swapcontext (2, 1);
+  if (status != 0)
+    {
+      printf ("%s: swapping contexts failed: %s\n",
+	      __FUNCTION__, strerror (status));
+      exit (1);
+    }
+  puts ("finish f2");
+  was_in_f2 = 1;
+}
+
+
+static int back_in_main;
+
+static void
+check_called (void)
+{
+  if (back_in_main == 0)
+    {
+      printf ("%s: program did not reach main again", __FUNCTION__);
+      _exit (1);
+    }
+}
+
+
+volatile int global;
+
+int
+main (void)
+{
+  char st1[32768];
+  time_t t0, t1;
+  int status;
+
+  atexit (check_called);
+
+  puts ("calibrating delay loop");
+  for (max = 0x10000; max < LLONG_MAX / 2; max *= 2)
+    {
+      t0 = time (NULL);
+      for (count = max; count > 0; count--);
+      t1 = time (NULL);
+      if (difftime (t1, t0) > 10.0)
+	break;
+    }
+
+  puts ("making contexts");
+
+  sig_getcontext (1);
+  if (! flags[1])
+    {
+      printf ("%s: context not retrieved\n", __FUNCTION__);
+      exit (1);
+    }
+
+  /* Play some tricks with this context.  */
+  if (++global == 1)
+    if (setcontext ((ucontext_t *) &ctx[1]) != 0)
+      {
+	if (errno == ENOSYS)
+	  {
+	    back_in_main = 1;
+	    exit (0);
+	  }
+	printf ("%s: setcontext: %m\n", __FUNCTION__);
+	exit (1);
+      }
+  if (global != 2)
+    {
+      printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
+      exit (1);
+    }
+
+  ctx[1].uc_stack.ss_sp = st1;
+  ctx[1].uc_stack.ss_size = sizeof st1;
+  ctx[1].uc_link = (ucontext_t *) &ctx[0];
+  {
+    ucontext_t tempctx = ctx[1];
+    makecontext ((ucontext_t *) &ctx[1], (void (*) (void)) f1, 4, 1, 2, 3, -4);
+
+    /* Without this check, a stub makecontext can make us spin forever.  */
+    if (memcmp (&tempctx, (void *) &ctx[1], sizeof ctx[1]) == 0)
+      {
+        puts ("makecontext was a no-op, presuming not implemented");
+        return 0;
+      }
+  }
+
+  sig_getcontext (2);
+  if (! flags[2])
+    {
+      printf ("%s: second context not retrieved\n", __FUNCTION__);
+      exit (1);
+    }
+
+  ctx[2].uc_stack.ss_sp = st2;
+  ctx[2].uc_stack.ss_size = sizeof st2;
+  ctx[2].uc_link = (ucontext_t *) &ctx[1];
+  makecontext ((ucontext_t *) &ctx[2], f2, 0);
+
+  puts ("swapping contexts");
+  status = sig_swapcontext (0, 2);
+  if (status != 0)
+    {
+      printf ("%s: swapping contexts failed: %s\n",
+	      __FUNCTION__, strerror (status));
+      exit (1);
+    }
+  puts ("back at main program");
+  back_in_main = 1;
+
+  if (was_in_f1 == 0)
+    {
+      puts ("didn't reach f1");
+      exit (1);
+    }
+  if (was_in_f2 == 0)
+    {
+      puts ("didn't reach f2");
+      exit (1);
+    }
+
+  puts ("test succeeded");
+  return 0;
+}