X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;ds=inline;f=lib%2Fc-stack.c;h=d260b47aa546122340ed91ba9e3e4e897c485b4c;hb=7b01a885219f9d3870cedcc5c049a80756271538;hp=a018e5158e256417f35021f7dfa9c283af469e6e;hpb=f49d92a13f08f505fe855afce40f173a6e7c922c;p=gnulib.git
diff --git a/lib/c-stack.c b/lib/c-stack.c
index a018e5158..d260b47aa 100644
--- a/lib/c-stack.c
+++ b/lib/c-stack.c
@@ -1,11 +1,12 @@
/* Stack overflow handling.
- Copyright (C) 2002, 2004 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2004, 2006, 2008, 2009 Free Software
+ Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -13,8 +14,7 @@
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+ along with this program. If not, see . */
/* Written by Paul Eggert. */
@@ -34,12 +34,10 @@
No attempt has been made to deal with multithreaded applications. */
-#if HAVE_CONFIG_H
-# include
-#endif
+#include
#ifndef __attribute__
-# if __GNUC__ < 3 || __STRICT_ANSI__
+# if __GNUC__ < 3
# define __attribute__(x)
# endif
#endif
@@ -51,51 +49,40 @@
#ifndef ENOTSUP
# define ENOTSUP EINVAL
#endif
-#ifndef EOVERFLOW
-# define EOVERFLOW EINVAL
-#endif
#include
#if ! HAVE_STACK_T && ! defined stack_t
typedef struct sigaltstack stack_t;
#endif
+#ifndef SIGSTKSZ
+# define SIGSTKSZ 16384
+#endif
#include
#include
-#if HAVE_SYS_RESOURCE_H
-/* Include sys/time.h here, because...
- SunOS-4.1.x fails to include .
- This gives "incomplete type" errors for ru_utime and tu_stime. */
-# if HAVE_SYS_TIME_H
-# include
-# endif
-# include
-#endif
-
+/* Posix 2001 declares ucontext_t in , Posix 200x in
+ . */
#if HAVE_UCONTEXT_H
# include
#endif
-#if HAVE_UNISTD_H
-# include
-#endif
-#ifndef STDERR_FILENO
-# define STDERR_FILENO 2
-#endif
+#include
-#if DEBUG
-# include
+#if HAVE_LIBSIGSEGV
+# include
#endif
#include "c-stack.h"
#include "exitfail.h"
-#if (HAVE_STRUCT_SIGACTION_SA_SIGACTION && defined SA_NODEFER \
- && defined SA_ONSTACK && defined SA_RESETHAND && defined SA_SIGINFO)
+#if defined SA_ONSTACK && defined SA_SIGINFO
# define SIGACTION_WORKS 1
#else
# define SIGACTION_WORKS 0
+# ifndef SA_ONSTACK
+# define SA_ONSTACK 0
+# endif
#endif
extern char *program_name;
@@ -127,11 +114,105 @@ die (int signo)
write (STDERR_FILENO, "\n", 1);
if (! signo)
_exit (exit_failure);
- kill (getpid (), signo);
+ raise (signo);
abort ();
}
-#if HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK
+#if (HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK \
+ && HAVE_STACK_OVERFLOW_HANDLING) || HAVE_LIBSIGSEGV
+
+/* Storage for the alternate signal stack. */
+static union
+{
+ char buffer[SIGSTKSZ];
+
+ /* These other members are for proper alignment. There's no
+ standard way to guarantee stack alignment, but this seems enough
+ in practice. */
+ long double ld;
+ long l;
+ void *p;
+} alternate_signal_stack;
+
+static void
+null_action (int signo __attribute__ ((unused)))
+{
+}
+
+#endif /* SIGALTSTACK || LIBSIGSEGV */
+
+/* Only use libsigsegv if we need it; platforms like Solaris can
+ detect stack overflow without the overhead of an external
+ library. */
+#if HAVE_LIBSIGSEGV && ! HAVE_XSI_STACK_OVERFLOW_HEURISTIC
+
+/* Nonzero if general segv handler could not be installed. */
+static volatile int segv_handler_missing;
+
+/* Handle a segmentation violation and exit if it cannot be stack
+ overflow. This function is async-signal-safe. */
+
+static int segv_handler (void *address __attribute__ ((unused)),
+ int serious)
+{
+# if DEBUG
+ {
+ char buf[1024];
+ sprintf (buf, "segv_handler serious=%d\n", serious);
+ write (STDERR_FILENO, buf, strlen (buf));
+ }
+# endif
+
+ /* If this fault is not serious, return 0 to let the stack overflow
+ handler take a shot at it. */
+ if (!serious)
+ return 0;
+ die (SIGSEGV);
+}
+
+/* Handle a segmentation violation that is likely to be a stack
+ overflow and exit. This function is async-signal-safe. */
+
+static void overflow_handler (int, stackoverflow_context_t)
+ __attribute__ ((noreturn));
+static void
+overflow_handler (int emergency,
+ stackoverflow_context_t context __attribute__ ((unused)))
+{
+# if DEBUG
+ {
+ char buf[1024];
+ sprintf (buf, "overflow_handler emergency=%d segv_handler_missing=%d\n",
+ emergency, segv_handler_missing);
+ write (STDERR_FILENO, buf, strlen (buf));
+ }
+# endif
+
+ die ((!emergency || segv_handler_missing) ? 0 : SIGSEGV);
+}
+
+int
+c_stack_action (void (*action) (int))
+{
+ segv_action = action ? action : null_action;
+ program_error_message = _("program error");
+ stack_overflow_message = _("stack overflow");
+
+ /* Always install the overflow handler. */
+ if (stackoverflow_install_handler (overflow_handler,
+ alternate_signal_stack.buffer,
+ sizeof alternate_signal_stack.buffer))
+ {
+ errno = ENOTSUP;
+ return -1;
+ }
+ /* Try installing a general handler; if it fails, then treat all
+ segv as stack overflow. */
+ segv_handler_missing = sigsegv_install_handler (segv_handler);
+ return 0;
+}
+
+#elif HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK && HAVE_STACK_OVERFLOW_HANDLING
/* Direction of the C runtime stack. This function is
async-signal-safe. */
@@ -147,19 +228,6 @@ find_stack_direction (char const *addr)
}
# endif
-/* Storage for the alternate signal stack. */
-static union
-{
- char buffer[SIGSTKSZ];
-
- /* These other members are for proper alignment. There's no
- standard way to guarantee stack alignment, but this seems enough
- in practice. */
- long double ld;
- long l;
- void *p;
-} alternate_signal_stack;
-
# if SIGACTION_WORKS
/* Handle a segmentation violation and exit. This function is
@@ -171,14 +239,21 @@ segv_handler (int signo, siginfo_t *info,
void *context __attribute__ ((unused)))
{
/* Clear SIGNO if it seems to have been a stack overflow. */
- if (0 < info->si_code)
- {
# if ! HAVE_XSI_STACK_OVERFLOW_HEURISTIC
- /* We can't easily determine whether it is a stack overflow; so
- assume that the rest of our program is perfect (!) and that
- this segmentation violation is a stack overflow. */
- signo = 0;
+ /* We can't easily determine whether it is a stack overflow; so
+ assume that the rest of our program is perfect (!) and that
+ this segmentation violation is a stack overflow.
+
+ Note that although both Linux and Solaris provide
+ sigaltstack, SA_ONSTACK, and SA_SIGINFO, currently only
+ Solaris satisfies the XSI heueristic. This is because
+ Solaris populates uc_stack with the details of the
+ interrupted stack, while Linux populates it with the details
+ of the current stack. */
+ signo = 0;
# else
+ if (0 < info->si_code)
+ {
/* If the faulting address is within the stack, or within one
page of the stack end, assume that it is a stack
overflow. */
@@ -188,7 +263,7 @@ segv_handler (int signo, siginfo_t *info,
char const *faulting_address = info->si_addr;
size_t s = faulting_address - stack_base;
size_t page_size = sysconf (_SC_PAGESIZE);
- if (find_stack_direction (0) < 0)
+ if (find_stack_direction (NULL) < 0)
s += page_size;
if (s < stack_size + page_size)
signo = 0;
@@ -203,40 +278,30 @@ segv_handler (int signo, siginfo_t *info,
write (STDERR_FILENO, buf, strlen (buf));
}
# endif
-# endif
}
+# endif
die (signo);
}
# endif
-static void
-null_action (int signo __attribute__ ((unused)))
-{
-}
-
-/* Set up ACTION so that it is invoked on C stack overflow. Return -1
- (setting errno) if this cannot be done.
-
- When ACTION is called, it is passed an argument equal to SIGSEGV
- for a segmentation violation that does not appear related to stack
- overflow, and is passed zero otherwise. On many platforms it is
- hard to tell; when in doubt, zero is passed.
-
- A null ACTION acts like an action that does nothing.
-
- ACTION must be async-signal-safe. ACTION together with its callees
- must not require more than SIGSTKSZ bytes of stack space. */
-
int
c_stack_action (void (*action) (int))
{
int r;
stack_t st;
+ struct sigaction act;
st.ss_flags = 0;
+# if SIGALTSTACK_SS_REVERSED
+ /* Irix mistakenly treats ss_sp as the upper bound, rather than
+ lower bound, of the alternate stack. */
+ st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ - sizeof (void *);
+ st.ss_size = sizeof alternate_signal_stack.buffer - sizeof (void *);
+# else
st.ss_sp = alternate_signal_stack.buffer;
st.ss_size = sizeof alternate_signal_stack.buffer;
- r = sigaltstack (&st, 0);
+# endif
+ r = sigaltstack (&st, NULL);
if (r != 0)
return r;
@@ -244,26 +309,28 @@ c_stack_action (void (*action) (int))
program_error_message = _("program error");
stack_overflow_message = _("stack overflow");
- {
-# if SIGACTION_WORKS
- struct sigaction act;
- sigemptyset (&act.sa_mask);
-
- /* POSIX 1003.1-2001 says SA_RESETHAND implies SA_NODEFER, but
- this is not true on Solaris 8 at least. It doesn't hurt to use
- SA_NODEFER here, so leave it in. */
- act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
-
- act.sa_sigaction = segv_handler;
+ sigemptyset (&act.sa_mask);
- return sigaction (SIGSEGV, &act, 0);
+# if SIGACTION_WORKS
+ /* POSIX 1003.1-2001 says SA_RESETHAND implies SA_NODEFER, but
+ this is not true on Solaris 8 at least. It doesn't hurt to use
+ SA_NODEFER here, so leave it in. */
+ act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
+ act.sa_sigaction = segv_handler;
# else
- return signal (SIGSEGV, die) == SIG_ERR ? -1 : 0;
+ act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
+ act.sa_handler = die;
# endif
- }
+
+# if FAULT_YIELDS_SIGBUS
+ if (sigaction (SIGBUS, &act, NULL) < 0)
+ return -1;
+# endif
+ return sigaction (SIGSEGV, &act, NULL);
}
-#else /* ! (HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK) */
+#else /* ! ((HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK
+ && HAVE_STACK_OVERFLOW_HANDLING) || HAVE_LIBSIGSEGV) */
int
c_stack_action (void (*action) (int) __attribute__ ((unused)))
@@ -273,39 +340,3 @@ c_stack_action (void (*action) (int) __attribute__ ((unused)))
}
#endif
-
-
-
-#if DEBUG
-
-int volatile exit_failure;
-
-static long
-recurse (char *p)
-{
- char array[500];
- array[0] = 1;
- return *p + recurse (array);
-}
-
-char *program_name;
-
-int
-main (int argc __attribute__ ((unused)), char **argv)
-{
- program_name = argv[0];
- fprintf (stderr,
- "The last output line should contain \"stack overflow\".\n");
- if (c_stack_action (0) == 0)
- return recurse ("\1");
- perror ("c_stack_action");
- return 1;
-}
-
-#endif /* DEBUG */
-
-/*
-Local Variables:
-compile-command: "gcc -DDEBUG -DHAVE_CONFIG_H -I.. -g -O -Wall -W c-stack.c"
-End:
-*/