diff mbox

[BZ,#18080] S390: Fix setcontext/swapcontext which are not restoring sigmask.

Message ID md757u$8vq$1@ger.gmane.org
State Committed
Headers show

Commit Message

Stefan Liebler March 4, 2015, 2:35 p.m. UTC
Hi,

this is an updated version of the patch.
The testcase is now using sig_atomic_t instead of int for handlerCalled
and missing spaces in function calls are added.
Now the first line describes the testcase.

I´ve changed swapcontext on s390/s390x, so that sigprocmask is only
called one time to get the current signal-mask and set the new one.

There is no issue with the return value %r2 of swapcontext():
In getcontext(), %r2 is set to zero just before gprs %r0...%r15 are
stored in ucp. In setcontext(), %r2 is loaded with the stored zero just
before returning. In swapcontext(), %r2 is clobbered with sigprocmask
call, but is loaded with the zero stored in ucp just before returning.
In swapcontext(), %r2 needs to be set to zero before storing gprs in
old-ucp.
If you call setcontext() with the old-ucp retrieved with swapcontext,
then swapcontext() will return zero.

The testcase is now additionally calling setcontext with the old-ctx
returned from the swapcontext() call and swapcontext()-return-value
is checked against zero.

Checked testsuite on s390/s390x and new testcase passes on x86_64.

Ok to commit?

Bye
Stefan

---
2015-03-04  Stefan Liebler  <stli@linux.vnet.ibm.com>

	[BZ #18080]
	* sysdeps/unix/sysv/linux/s390/s390-32/setcontext.S
	(__setcontext): Use SIG_SETMASK instead of SIG_BLOCK.
	* sysdeps/unix/sysv/linux/s390/s390-64/setcontext.S
	(__setcontext): Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/swapcontext.S
	(__swapcontext): Use SIG_SETMASK instead of SIG_BLOCK.
	Call rt_sigprocmask syscall one time to set new signal mask
	and retrieve the current signal mask instead of two calls.
	* sysdeps/unix/sysv/linux/s390/s390-64/swapcontext.S
	(__swapcontext): Likewise.
	* stdlib/Makefile (tests): Add new testcase tst-setcontext2.
	* stdlib/tst-setcontext2.c: New file.
diff mbox

Patch

diff --git a/stdlib/Makefile b/stdlib/Makefile
index 92ceca7..c78fdb5 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -66,11 +66,11 @@  test-srcs	:= tst-fmtmsg
 tests		:= tst-strtol tst-strtod testmb testrand testsort testdiv   \
 		   test-canon test-canon2 tst-strtoll tst-environ	    \
 		   tst-xpg-basename tst-random tst-random2 tst-bsearch	    \
-		   tst-limits tst-rand48 bug-strtod tst-setcontext	    \
-		   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-limits tst-rand48 bug-strtod tst-setcontext          \
+		   tst-setcontext2 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-makecontext3 bug-getcontext bug-fmtmsg1		    \
 		   tst-secure-getenv tst-strtod-overflow tst-strtod-round   \
 		   tst-tininess tst-strtod-underflow tst-tls-atexit
diff --git a/stdlib/tst-setcontext2.c b/stdlib/tst-setcontext2.c
new file mode 100644
index 0000000..8582cc0
--- /dev/null
+++ b/stdlib/tst-setcontext2.c
@@ -0,0 +1,230 @@ 
+/* Testcase checks, if setcontext(), swapcontext() restores signal-mask
+   and if pending signals are delivered after those calls.
+   Copyright (C) 2015 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+volatile int global;
+volatile sig_atomic_t handlerCalled;
+
+static void
+check (const char *funcName)
+{
+  sigset_t set;
+
+  /* check if SIGUSR2 is unblocked after setcontext-call.  */
+  sigprocmask (SIG_BLOCK, NULL, &set);
+
+  if (sigismember (&set, SIGUSR2) != 0)
+    {
+      printf ("FAIL: SIGUSR2 is blocked after %s.\n", funcName);
+      exit (1);
+    }
+
+  if (sigismember (&set, SIGUSR1) != 1)
+    {
+      printf ("FAIL: SIGUSR1 is not blocked after %s.\n", funcName);
+      exit (1);
+    }
+}
+
+static void
+signalmask (int how, int signum)
+{
+  sigset_t set;
+  sigemptyset (&set);
+  sigaddset (&set, signum);
+  if (sigprocmask (how, &set, NULL) != 0)
+    {
+      printf ("FAIL: sigprocmaks (%d, %d, NULL): %m\n", how, signum);
+      exit (1);
+    }
+}
+
+static void
+signalpending (int signum, const char *msg)
+{
+  sigset_t set;
+  sigemptyset (&set);
+  if (sigpending (&set) != 0)
+    {
+      printf ("FAIL: sigpending: %m\n");
+      exit (1);
+    }
+  if (sigismember (&set, SIGUSR2) != 1)
+    {
+      printf ("FAIL: Signal %d is not pending %s\n", signum, msg);
+      exit (1);
+    }
+}
+
+static void
+handler (int __attribute__ ((unused)) signum)
+{
+  handlerCalled ++;
+}
+
+static int
+do_test (void)
+{
+  ucontext_t ctx, oldctx;
+  struct sigaction action;
+  pid_t pid;
+
+  pid = getpid ();
+
+  /* unblock SIGUSR2 */
+  signalmask (SIG_UNBLOCK, SIGUSR2);
+
+  /* block SIGUSR1 */
+  signalmask (SIG_BLOCK, SIGUSR1);
+
+  /* register handler for SIGUSR2  */
+  action.sa_flags = 0;
+  action.sa_handler = handler;
+  sigemptyset (&action.sa_mask);
+  sigaction (SIGUSR2, &action, NULL);
+
+  if (getcontext (&ctx) != 0)
+    {
+      printf ("FAIL: getcontext: %m\n");
+      exit (1);
+    }
+
+  global++;
+
+  if (global == 1)
+    {
+      puts ("after getcontext");
+
+      /* block SIGUSR2  */
+      signalmask (SIG_BLOCK, SIGUSR2);
+
+      /* send SIGUSR2 to me  */
+      handlerCalled = 0;
+      kill (pid, SIGUSR2);
+
+      /* was SIGUSR2 handler called?  */
+      if (handlerCalled != 0)
+	{
+	  puts ("FAIL: signal handler was called, but signal was blocked.");
+	  exit (1);
+	}
+
+      /* is SIGUSR2 pending?  */
+      signalpending (SIGUSR2, "before setcontext");
+
+      /* SIGUSR2 will be unblocked by setcontext-call.  */
+      if (setcontext (&ctx) != 0)
+	{
+	  printf ("FAIL: setcontext: %m\n");
+	  exit (1);
+	}
+    }
+  else if (global == 2)
+    {
+      puts ("after setcontext");
+
+      /* check SIGUSR1/2  */
+      check ("setcontext");
+
+      /* was SIGUSR2 handler called? */
+      if (handlerCalled != 1)
+	{
+	  puts ("FAIL: signal handler was not called after setcontext.");
+	  exit (1);
+	}
+
+      /* block SIGUSR2 */
+      signalmask (SIG_BLOCK, SIGUSR2);
+
+      /* send SIGUSR2 to me  */
+      handlerCalled = 0;
+      kill (pid, SIGUSR2);
+
+      /* was SIGUSR2 handler called?  */
+      if (handlerCalled != 0)
+	{
+	  puts ("FAIL: signal handler was called, but signal was blocked.");
+	  exit (1);
+	}
+
+      /* is SIGUSR2 pending?  */
+      signalpending (SIGUSR2, "before swapcontext");
+
+      if (swapcontext (&oldctx, &ctx) != 0)
+	{
+	  printf ("FAIL: swapcontext: %m\n");
+	  exit (1);
+	}
+
+      puts ("after returned from swapcontext");
+
+      if (global != 3)
+	{
+	  puts ("FAIL: returned from swapcontext without ctx-context called.");
+	  exit (1);
+	}
+
+      puts ("test succeeded");
+      return 0;
+    }
+  else if ( global != 3 )
+    {
+      puts ("FAIL: 'global' not incremented three times");
+      exit (1);
+    }
+
+  puts ("after swapcontext");
+  /* check SIGUSR1/2  */
+  check ("swapcontext");
+
+  /* was SIGUSR2 handler called? */
+  if (handlerCalled != 1)
+    {
+      puts ("FAIL: signal handler was not called after swapcontext.");
+      exit (1);
+    }
+
+  /* check sigmask in old context of swapcontext-call  */
+  if (sigismember (&oldctx.uc_sigmask, SIGUSR2) != 1)
+    {
+      puts ("FAIL: SIGUSR2 is not blocked in oldctx.uc_sigmask.");
+      exit (1);
+    }
+
+  if (sigismember (&oldctx.uc_sigmask, SIGUSR1) != 1)
+    {
+      puts ("FAIL: SIGUSR1 is not blocked in oldctx.uc_sigmaks.");
+      exit (1);
+    }
+
+  /* change to old context, which was gathered by swapcontext() call.  */
+  setcontext (&oldctx);
+
+  puts ("FAIL: returned from setcontext (&oldctx)");
+  exit (1);
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/setcontext.S b/sysdeps/unix/sysv/linux/s390/s390-32/setcontext.S
index 22fb3ae..59cf4a8 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/setcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/setcontext.S
@@ -34,7 +34,7 @@  ENTRY(__setcontext)
 	lr	%r1,%r2
 
 	/* rt_sigprocmask (SIG_SETMASK, &sc->sc_mask, NULL, sigsetsize).  */
-	la      %r2,SIG_BLOCK
+	la      %r2,SIG_SETMASK
 	la	%r3,SC_MASK(%r1)
 	slr	%r4,%r4
 	lhi	%r5,_NSIG8
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/swapcontext.S b/sysdeps/unix/sysv/linux/s390/s390-32/swapcontext.S
index c40f465..ac6568b 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/swapcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/swapcontext.S
@@ -24,7 +24,7 @@ 
 /*  __swapcontext (ucontext_t *oucp, const ucontext_t *ucp)
 
   Saves the machine context in oucp such that when it is activated,
-  it appears as if __swapcontextt() returned again, restores the
+  it appears as if __swapcontext() returned again, restores the
   machine context in ucp and thereby resumes execution in that
   context.
 
@@ -39,13 +39,6 @@  ENTRY(__swapcontext)
 	lr	%r1,%r2
 	lr      %r0,%r3
 
-	/* sigprocmask (SIG_BLOCK, NULL, &sc->sc_mask).  */
-	la      %r2,SIG_BLOCK
-	slr	%r3,%r3
-	la	%r4,SC_MASK(%r1)
-	lhi	%r5,_NSIG8
-	svc	SYS_ify(rt_sigprocmask)
-
 	/* Store fpu context.  */
 	stfpc   SC_FPC(%r1)
 	std     %f0,SC_FPRS(%r1)
@@ -74,11 +67,12 @@  ENTRY(__swapcontext)
 	/* Store general purpose registers.  */
 	stm     %r0,%r15,SC_GPRS(%r1)
 
-	/* sigprocmask (SIG_SETMASK, &sc->sc_mask, NULL).  */
-	la      %r2,SIG_BLOCK
+	/* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, &oucp->uc_sigmask,
+	   sigsetsize).  */
+	la      %r2,SIG_SETMASK
 	lr	%r5,%r0
 	la	%r3,SC_MASK(%r5)
-	slr	%r4,%r4
+	la	%r4,SC_MASK(%r1)
 	lhi	%r5,_NSIG8
 	svc	SYS_ify(rt_sigprocmask)
 
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/setcontext.S b/sysdeps/unix/sysv/linux/s390/s390-64/setcontext.S
index d83fa42..388c7d6 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/setcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/setcontext.S
@@ -34,7 +34,7 @@  ENTRY(__setcontext)
 	lgr	%r1,%r2
 
 	/* sigprocmask (SIG_SETMASK, &sc->sc_mask, NULL).  */
-	la      %r2,SIG_BLOCK
+	la      %r2,SIG_SETMASK
 	la	%r3,SC_MASK(%r1)
 	slgr	%r4,%r4
 	lghi	%r5,_NSIG8
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/swapcontext.S b/sysdeps/unix/sysv/linux/s390/s390-64/swapcontext.S
index d36a623..e0336da 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/swapcontext.S
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/swapcontext.S
@@ -24,7 +24,7 @@ 
 /*  __swapcontext (ucontext_t *oucp, const ucontext_t *ucp)
 
   Saves the machine context in oucp such that when it is activated,
-  it appears as if __swapcontextt() returned again, restores the
+  it appears as if __swapcontext() returned again, restores the
   machine context in ucp and thereby resumes execution in that
   context.
 
@@ -39,13 +39,6 @@  ENTRY(__swapcontext)
 	lgr	%r1,%r2
 	lgr     %r0,%r3
 
-	/* sigprocmask (SIG_BLOCK, NULL, &sc->sc_mask).  */
-	la      %r2,SIG_BLOCK
-	slgr	%r3,%r3
-	la	%r4,SC_MASK(%r1)
-	lghi	%r5,_NSIG8
-	svc	SYS_ify(rt_sigprocmask)
-
 	/* Store fpu context.  */
 	stfpc   SC_FPC(%r1)
 	std     %f0,SC_FPRS(%r1)
@@ -74,12 +67,13 @@  ENTRY(__swapcontext)
 	/* Store general purpose registers.  */
 	stmg    %r0,%r15,SC_GPRS(%r1)
 
-	/* rt_sigprocmask (SIG_SETMASK, &sc->sc_mask, NULL, sigsetsize).  */
-	la      %r2,SIG_BLOCK
+	/* rt_sigprocmask (SIG_SETMASK, &ucp->uc_sigmask, &oucp->uc_sigmask,
+	   sigsetsize).  */
+	la      %r2,SIG_SETMASK
 	lgr	%r5,%r0
 	la	%r3,SC_MASK(%r5)
+	la	%r4,SC_MASK(%r1)
 	lghi	%r5,_NSIG8
-	slgr	%r4,%r4
 	svc	SYS_ify(rt_sigprocmask)
 
 	/* Load fpu context.  */