Add test case for ____longjmp_chk vs signal stacks.

2 files changed, 116 insertions, 1 deletions

diff --git a/debug/Makefile b/debug/Makefile
index 181169b90d..99c8092074 100644
--- a/debug/Makefile
+++ b/debug/Makefile
@@ -118,7 +118,8 @@ LDFLAGS-tst-lfschk6 = -lstdc++
 
 tests = backtrace-tst tst-longjmp_chk tst-chk1 tst-chk2 tst-chk3 \
 	tst-lfschk1 tst-lfschk2 tst-lfschk3 test-strcpy_chk test-stpcpy_chk \
-	tst-chk4 tst-chk5 tst-chk6 tst-lfschk4 tst-lfschk5 tst-lfschk6
+	tst-chk4 tst-chk5 tst-chk6 tst-lfschk4 tst-lfschk5 tst-lfschk6 \
+	tst-longjmp_chk2
 
 extra-libs = libSegFault libpcprofile
 extra-libs-others = $(extra-libs)
diff --git a/debug/tst-longjmp_chk2.c b/debug/tst-longjmp_chk2.c
new file mode 100644
index 0000000000..22d8bf0941
--- /dev/null
+++ b/debug/tst-longjmp_chk2.c
@@ -0,0 +1,114 @@
+/* Test case mostly written by Paolo Bonzini <pbonzini@redhat.com>.  */
+#include <assert.h>
+#include <setjmp.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+
+
+static jmp_buf mainloop;
+static sigset_t mainsigset;
+static int pass;
+
+
+static void
+stackoverflow_handler (int sig)
+{
+  stack_t altstack;
+  pass++;
+  sigaltstack (NULL, &altstack);
+  /* Using printf is not really kosher in signal handlers but we know
+     it will work.  */
+  printf ("%*sin signal handler\n", pass, "");
+  if (altstack.ss_flags & SS_ONSTACK)
+    printf ("%*son alternate stack\n", pass, "");
+  siglongjmp (mainloop, pass);
+}
+
+
+static volatile int *
+recurse_1 (int n, volatile int *p)
+{
+  if (n >= 0)
+    *recurse_1 (n + 1, p) += n;
+  return p;
+}
+
+
+static int
+recurse (int n)
+{
+  int sum = 0;
+  return *recurse_1 (n, &sum);
+}
+
+
+static int
+do_test (void)
+{
+  char mystack[SIGSTKSZ];
+  stack_t altstack;
+  struct sigaction action;
+  sigset_t emptyset;
+  /* Before starting the endless recursion, try to be friendly to the user's
+     machine.  On some Linux 2.2.x systems, there is no stack limit for user
+     processes at all.  We don't want to kill such systems.  */
+  struct rlimit rl;
+  rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
+  setrlimit (RLIMIT_STACK, &rl);
+  /* Install the alternate stack.  */
+  altstack.ss_sp = mystack;
+  altstack.ss_size = sizeof (mystack);
+  altstack.ss_flags = 0; /* no SS_DISABLE */
+  if (sigaltstack (&altstack, NULL) < 0)
+    {
+      puts ("first sigaltstack failed");
+      return 0;
+    }
+  /* Install the SIGSEGV handler.  */
+  sigemptyset (&action.sa_mask);
+  action.sa_handler = &stackoverflow_handler;
+  action.sa_flags = SA_ONSTACK;
+  sigaction (SIGSEGV, &action, (struct sigaction *) NULL);
+  sigaction (SIGBUS, &action, (struct sigaction *) NULL);
+
+  /* Save the current signal mask.  */
+  sigemptyset (&emptyset);
+  sigprocmask (SIG_BLOCK, &emptyset, &mainsigset);
+
+  /* Provoke two stack overflows in a row.  */
+  if (sigsetjmp (mainloop, 1) != 0)
+    {
+      assert (pass != 0);
+      printf ("%*sout of signal handler\n", pass, "");
+    }
+  else
+    assert (pass == 0);
+
+  sigaltstack (NULL, &altstack);
+  if (altstack.ss_flags & SS_ONSTACK)
+    printf ("%*son alternate stack\n", pass, "");
+  else
+    printf ("%*snot on alternate stack\n", pass, "");
+
+  if (pass < 2)
+    {
+      recurse (0);
+      puts ("recurse call returned");
+      return 2;
+    }
+
+  altstack.ss_flags |= SS_DISABLE;
+  if (sigaltstack (&altstack, NULL) == -1)
+    printf ("disabling alternate stack failed\n");
+  else
+    printf ("disabling alternate stack succeeded \n");
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"