* c-stack: Catching stack overflow on most platforms without libsigsegv
@ 2021-05-17 1:49 Bruno Haible
2021-05-18 6:00 ` Paul Eggert
0 siblings, 1 reply; 3+ messages in thread
From: Bruno Haible @ 2021-05-17 1:49 UTC (permalink / raw)
To: Paul Eggert; +Cc: bug-gnulib
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Hi Paul,
Here is a proposed patch to make use of the new 'sigsegv' module
(quasi a mini libsigsegv without library dependencies), so that
* On most systems, catching stack overflow becomes possible without
link dependencies. (The only notable exceptions, where GNU libsigsegv
are still needed, are native Windows and older versions of various
OSes: Mac OS X 10.5, probably NetBSD 7, and such.)
* In particular, glibc systems are no longer left behind, compared to
Solaris.
I have verified this patch by building and m4 snapshot with it on
- glibc
- newest glibc > 2.33 snapshot
- Solaris 11/sparc64
- Cygwin
- Minix (just to test a case where catching stack overflow is not supported).
And I had tested the 'sigsegv' module on ca. 58 platforms, from IRIX 6.5 to
musl libc on Linux/s390x.
Bruno
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From 7832467d9d79753185664f702c50fb91dd5311eb Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Mon, 17 May 2021 03:36:35 +0200
Subject: [PATCH] c-stack: Catching stack overflow on most platforms without
libsigsegv.
* lib/c-stack.c: Remove all Solaris-specific code. Include <sigsegv.h>
always.
* m4/c-stack.m4: Remove all Solaris-specific code.
(gl_C_STACK): Test $with_libsigsegv from module 'sigsegv'.
* modules/c-stack (Files): Remove m4/libsigsegv.m4.
(Depends-on): Add sigsegv. Remove havelib, intprops, inttypes, mempcpy,
sigaction, stdbool.
---
ChangeLog | 11 ++
lib/c-stack.c | 188 +-------------------------
m4/c-stack.m4 | 413 ++------------------------------------------------------
modules/c-stack | 8 +-
4 files changed, 27 insertions(+), 593 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index e3ab1ff..ae60171 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
2021-05-16 Bruno Haible <bruno@clisp.org>
+ c-stack: Catching stack overflow on most platforms without libsigsegv.
+ * lib/c-stack.c: Remove all Solaris-specific code. Include <sigsegv.h>
+ always.
+ * m4/c-stack.m4: Remove all Solaris-specific code.
+ (gl_C_STACK): Test $with_libsigsegv from module 'sigsegv'.
+ * modules/c-stack (Files): Remove m4/libsigsegv.m4.
+ (Depends-on): Add sigsegv. Remove havelib, intprops, inttypes, mempcpy,
+ sigaction, stdbool.
+
+2021-05-16 Bruno Haible <bruno@clisp.org>
+
sigsegv, c-stack: Avoid compilation error with glibc >= 2.34.
* lib/sigsegv.in.h (SIGSTKSZ): On glibc systems, redefine to a suitable
constant.
diff --git a/lib/c-stack.c b/lib/c-stack.c
index 3e8cd25..1965bdd 100644
--- a/lib/c-stack.c
+++ b/lib/c-stack.c
@@ -39,59 +39,27 @@
#include <errno.h>
#include <inttypes.h>
-
#include <signal.h>
-#if ! HAVE_STACK_T && ! defined stack_t
-typedef struct sigaltstack stack_t;
-#endif
-
-#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
-
-/* Pre-2008 POSIX declared ucontext_t in ucontext.h instead of signal.h. */
-#if HAVE_UCONTEXT_H
-# include <ucontext.h>
-#endif
-
#include <unistd.h>
#if DEBUG
# include <stdio.h>
#endif
+#include <sigsegv.h>
+
+#include "exitfail.h"
+#include "getprogname.h"
#include "idx.h"
+#include "ignore-value.h"
#include "gettext.h"
#define _(msgid) gettext (msgid)
-#if HAVE_LIBSIGSEGV
-# include <sigsegv.h>
-#endif
-
-/* Use libsigsegv only if needed; kernels like Solaris can detect
- stack overflow without the overhead of an external library.
- However, BOGUS_SI_ADDR_ON_STACK_OVERFLOW indicates a buggy
- Solaris kernel, and a too-small LIBSIGSEGV_VERSION indicates a
- libsigsegv so old that it does not work around the bug. */
-#define USE_LIBSIGSEGV (!HAVE_XSI_STACK_OVERFLOW_HEURISTIC && HAVE_LIBSIGSEGV \
- && ! (BOGUS_SI_ADDR_UPON_STACK_OVERFLOW \
- && LIBSIGSEGV_VERSION < 0x020D))
-
-#include "exitfail.h"
-#include "ignore-value.h"
-#include "intprops.h"
-#include "getprogname.h"
-
-#if defined SA_ONSTACK && defined SA_SIGINFO
-# define SIGINFO_WORKS 1
-#else
-# define SIGINFO_WORKS 0
-# ifndef SA_ONSTACK
-# define SA_ONSTACK 0
-# endif
-#endif
+#if HAVE_STACK_OVERFLOW_RECOVERY
/* Storage for the alternate signal stack.
64 KiB is not too large for Gnulib-using apps, and is large enough
@@ -113,9 +81,6 @@ static _GL_ASYNC_SAFE void (* volatile segv_action) (int);
static char const * volatile program_error_message;
static char const * volatile stack_overflow_message;
-#if (USE_LIBSIGSEGV \
- || (HAVE_DECL_SIGALTSTACK && HAVE_STACK_OVERFLOW_HANDLING))
-
/* Output an error message, then exit with status EXIT_FAILURE if it
appears to have been a stack overflow, or with a core dump
otherwise. This function is async-signal-safe. */
@@ -125,12 +90,6 @@ static char const * volatile progname;
static _GL_ASYNC_SAFE _Noreturn void
die (int signo)
{
-# if !SIGINFO_WORKS && !USE_LIBSIGSEGV
- /* 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;
-# endif
segv_action (signo);
char const *message = signo ? program_error_message : stack_overflow_message;
@@ -171,10 +130,6 @@ null_action (int signo _GL_UNUSED)
{
}
-#endif /* SIGALTSTACK || LIBSIGSEGV */
-
-#if USE_LIBSIGSEGV
-
/* Pacify GCC 9.3.1, which otherwise would complain about segv_handler. */
# if 4 < __GNUC__ + (6 <= __GNUC_MINOR__)
# pragma GCC diagnostic ignored "-Wsuggest-attribute=pure"
@@ -247,136 +202,7 @@ c_stack_action (_GL_ASYNC_SAFE void (*action) (int))
return 0;
}
-#elif HAVE_DECL_SIGALTSTACK && HAVE_STACK_OVERFLOW_HANDLING
-
-# if SIGINFO_WORKS
-
-static size_t volatile page_size;
-
-/* Handle a segmentation violation and exit. This function is
- async-signal-safe. */
-
-static _GL_ASYNC_SAFE _Noreturn void
-segv_handler (int signo, siginfo_t *info, void *context _GL_UNUSED)
-{
- /* Clear SIGNO if it seems to have been a stack overflow. */
-
- /* If si_code is nonpositive, something like raise (SIGSEGV) occurred
- so it cannot be a stack overflow. */
- bool cannot_be_stack_overflow = info->si_code <= 0;
-
- /* An unaligned address cannot be a stack overflow. */
-# if FAULT_YIELDS_SIGBUS
- cannot_be_stack_overflow |= signo == SIGBUS && info->si_code == BUS_ADRALN;
-# endif
-
- /* If we can't easily determine that it is not a stack overflow,
- 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 heuristic. 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. */
- if (!cannot_be_stack_overflow)
- {
-# if BOGUS_SI_ADDR_UPON_STACK_OVERFLOW
- signo = 0;
-# else
- /* If the faulting address is within the stack, or within one
- page of the stack, assume that it is a stack overflow. */
- uintptr_t faulting_address = (uintptr_t) info->si_addr;
-
- /* On all platforms we know of, the first page is not in the
- stack to catch null pointer dereferening. However, all other
- pages might be in the stack. */
- void *stack_base = (void *) (uintptr_t) page_size;
- uintptr_t stack_size = 0; stack_size -= page_size;
-# if HAVE_XSI_STACK_OVERFLOW_HEURISTIC
- /* Tighten the stack bounds via the XSI heuristic. */
- ucontext_t const *user_context = context;
- stack_base = user_context->uc_stack.ss_sp;
- stack_size = user_context->uc_stack.ss_size;
-# endif
- uintptr_t base = (uintptr_t) stack_base,
- lo = (INT_SUBTRACT_WRAPV (base, page_size, &lo) || lo < page_size
- ? page_size : lo),
- hi = ((INT_ADD_WRAPV (base, stack_size, &hi)
- || INT_ADD_WRAPV (hi, page_size - 1, &hi))
- ? UINTPTR_MAX : hi);
- if (lo <= faulting_address && faulting_address <= hi)
- signo = 0;
-# endif
-
-# if DEBUG
- {
- char buf[1024];
- ignore_value (write (STDERR_FILENO, buf,
- sprintf (buf,
- ("segv_handler code=%d fault=%p base=%p"
- " size=0x%zx page=0x%zx signo=%d\n"),
- info->si_code, info->si_addr, stack_base,
- stack_size, page_size, signo)));
- }
-# endif
- }
-
- die (signo);
-}
-# endif
-
-int
-c_stack_action (_GL_ASYNC_SAFE void (*action) (int))
-{
- stack_t st;
- st.ss_flags = 0;
- st.ss_sp = alternate_signal_stack;
- st.ss_size = sizeof alternate_signal_stack;
-# if SIGALTSTACK_SS_REVERSED
- /* Irix mistakenly treats ss_sp as the upper bound, rather than
- lower bound, of the alternate stack. */
- st.ss_size -= sizeof (void *);
- char *ss_sp = st.ss_sp;
- st.ss_sp = ss_sp + st.ss_size;
-# endif
- int r = sigaltstack (&st, NULL);
- if (r != 0)
- return r;
-
- segv_action = action ? action : null_action;
- program_error_message = _("program error");
- stack_overflow_message = _("stack overflow");
- progname = getprogname ();
-
-# if SIGINFO_WORKS
- page_size = sysconf (_SC_PAGESIZE);
-# endif
-
- struct sigaction act;
- sigemptyset (&act.sa_mask);
-
-# if SIGINFO_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
- 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 /* ! (USE_LIBSIGSEGV
- || (HAVE_DECL_SIGALTSTACK && HAVE_STACK_OVERFLOW_HANDLING)) */
+#else /* !HAVE_STACK_OVERFLOW_RECOVERY */
int
c_stack_action (_GL_ASYNC_SAFE void (*action) (int) _GL_UNUSED)
diff --git a/m4/c-stack.m4 b/m4/c-stack.m4
index 3131dd5..7cccb06 100644
--- a/m4/c-stack.m4
+++ b/m4/c-stack.m4
@@ -7,412 +7,15 @@
# Written by Paul Eggert.
-# serial 22
-
-AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
- [
- AC_REQUIRE([AC_CANONICAL_HOST])
- AC_CHECK_FUNCS_ONCE([setrlimit])
- AC_CHECK_HEADERS_ONCE([ucontext.h])
-
- dnl List of signals that are sent when an invalid virtual memory address
- dnl is accessed, or when the stack overflows.
- dnl Either { SIGSEGV } or { SIGSEGV, SIGBUS }.
- case "$host_os" in
- sunos4* | freebsd* | dragonfly* | midnightbsd* | openbsd* | mirbsd* | netbsd* | kfreebsd* | knetbsd*) # BSD systems
- FAULT_YIELDS_SIGBUS=1 ;;
- hpux*) # HP-UX
- FAULT_YIELDS_SIGBUS=1 ;;
- macos* | darwin*) # Mac OS X
- FAULT_YIELDS_SIGBUS=1 ;;
- gnu*) # Hurd
- FAULT_YIELDS_SIGBUS=1 ;;
- *)
- FAULT_YIELDS_SIGBUS=0 ;;
- esac
- AC_DEFINE_UNQUOTED([FAULT_YIELDS_SIGBUS], [$FAULT_YIELDS_SIGBUS],
- [Define to 1 if an invalid memory address access may yield a SIGBUS.])
-
- AC_CACHE_CHECK([for working C stack overflow detection],
- [gl_cv_sys_stack_overflow_works],
- [AC_RUN_IFELSE([AC_LANG_SOURCE(
- [[
- #include <unistd.h>
- #include <signal.h>
- #if HAVE_SETRLIMIT
- # include <sys/types.h>
- # include <sys/time.h>
- # include <sys/resource.h>
- #endif
- /* In glibc >= 2.34, when _GNU_SOURCE is defined, SIGSTKSZ is
- no longer a compile-time constant. But we need a simple
- constant here. */
- #if __GLIBC__ >= 2
- # undef SIGSTKSZ
- # if defined __ia64__
- # define SIGSTKSZ 262144
- # else
- # define SIGSTKSZ 16384
- # endif
- #endif
- #ifndef SIGSTKSZ
- # define SIGSTKSZ 16384
- #endif
-
- static union
- {
- char buffer[2 * SIGSTKSZ];
- long double ld;
- long u;
- void *p;
- } alternate_signal_stack;
-
- static void
- segv_handler (int signo)
- {
- _exit (0);
- }
-
- static int
- c_stack_action ()
- {
- stack_t st;
- struct sigaction act;
- int r;
-
- st.ss_flags = 0;
- /* Use the midpoint to avoid Irix sigaltstack bug. */
- st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ;
- st.ss_size = SIGSTKSZ;
- r = sigaltstack (&st, 0);
- if (r != 0)
- return 1;
-
- sigemptyset (&act.sa_mask);
- act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
- act.sa_handler = segv_handler;
- #if FAULT_YIELDS_SIGBUS
- if (sigaction (SIGBUS, &act, 0) < 0)
- return 2;
- #endif
- if (sigaction (SIGSEGV, &act, 0) < 0)
- return 3;
- return 0;
- }
- static volatile int *
- recurse_1 (volatile int n, volatile int *p)
- {
- if (n >= 0)
- *recurse_1 (n + 1, p) += n;
- return p;
- }
- static int
- recurse (volatile int n)
- {
- int sum = 0;
- return *recurse_1 (n, &sum);
- }
- int
- main ()
- {
- int result;
- #if HAVE_SETRLIMIT && defined RLIMIT_STACK
- /* 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);
- #endif
-
- result = c_stack_action ();
- if (result != 0)
- return result;
- return recurse (0);
- }
- ]])],
- [gl_cv_sys_stack_overflow_works=yes],
- [gl_cv_sys_stack_overflow_works=no],
- [case "$host_os" in
- # Guess no on native Windows.
- mingw*) gl_cv_sys_stack_overflow_works="guessing no" ;;
- *) gl_cv_sys_stack_overflow_works=cross-compiling ;;
- esac
- ])
- ])
-
- if test "$gl_cv_sys_stack_overflow_works" = yes; then
- AC_DEFINE([HAVE_STACK_OVERFLOW_HANDLING], [1],
- [Define to 1 if extending the stack slightly past the limit causes
- a SIGSEGV which can be handled on an alternate stack established
- with sigaltstack.])
-
- dnl The ss_sp field of a stack_t is, according to POSIX, the lowest address
- dnl of the memory block designated as an alternate stack. But IRIX 5.3
- dnl interprets it as the highest address!
- AC_CACHE_CHECK([for correct stack_t interpretation],
- [gl_cv_sigaltstack_low_base], [
- AC_RUN_IFELSE([
- AC_LANG_SOURCE([[
-#include <stdlib.h>
-#include <signal.h>
-#if HAVE_SYS_SIGNAL_H
-# include <sys/signal.h>
-#endif
-/* In glibc >= 2.34, when _GNU_SOURCE is defined, SIGSTKSZ is no longer a
- compile-time constant. But we need a simple constant here. */
-#if __GLIBC__ >= 2
-# undef SIGSTKSZ
-# if defined __ia64__
-# define SIGSTKSZ 262144
-# else
-# define SIGSTKSZ 16384
-# endif
-#endif
-#ifndef SIGSTKSZ
-# define SIGSTKSZ 16384
-#endif
-volatile char *stack_lower_bound;
-volatile char *stack_upper_bound;
-static void check_stack_location (volatile char *addr)
-{
- if (addr >= stack_lower_bound && addr <= stack_upper_bound)
- exit (0);
- else
- exit (1);
-}
-static void stackoverflow_handler (int sig)
-{
- char dummy;
- check_stack_location (&dummy);
-}
-int main ()
-{
- char mystack[2 * SIGSTKSZ];
- stack_t altstack;
- struct sigaction action;
- /* Install the alternate stack. */
- altstack.ss_sp = mystack + SIGSTKSZ;
- altstack.ss_size = SIGSTKSZ;
- stack_lower_bound = (char *) altstack.ss_sp;
- stack_upper_bound = (char *) altstack.ss_sp + altstack.ss_size - 1;
- altstack.ss_flags = 0; /* no SS_DISABLE */
- if (sigaltstack (&altstack, NULL) < 0)
- exit (2);
- /* Install the SIGSEGV handler. */
- sigemptyset (&action.sa_mask);
- action.sa_handler = &stackoverflow_handler;
- action.sa_flags = SA_ONSTACK;
- if (sigaction (SIGSEGV, &action, (struct sigaction *) NULL) < 0)
- exit(3);
- /* Provoke a SIGSEGV. */
- raise (SIGSEGV);
- exit (4);
-}]])],
- [gl_cv_sigaltstack_low_base=yes],
- [gl_cv_sigaltstack_low_base=no],
- [gl_cv_sigaltstack_low_base=cross-compiling])])
- if test "$gl_cv_sigaltstack_low_base" = no; then
- AC_DEFINE([SIGALTSTACK_SS_REVERSED], [1],
- [Define if sigaltstack() interprets the stack_t.ss_sp field
- incorrectly, as the highest address of the alternate stack range
- rather than as the lowest address.])
- fi
-
- case $host_os--$host_cpu in
- solaris2.11--sparc*)
- AC_DEFINE([BOGUS_SI_ADDR_UPON_STACK_OVERFLOW], [1],
- [Define to 1 if the faulting address (info->si_addr)
- might be incorrect on stack overflow.])
- gl_bogus_si_addr=1;;
- *) gl_bogus_si_addr=0;;
- esac
-
- AC_CACHE_CHECK([for precise C stack overflow detection],
- [gl_cv_sys_xsi_stack_overflow_heuristic],
- [dnl On Linux/sparc64 (both in 32-bit and 64-bit mode), it would be wrong
- dnl to set HAVE_XSI_STACK_OVERFLOW_HEURISTIC to 1, because the third
- dnl argument passed to the segv_handler is a 'struct sigcontext *', not
- dnl an 'ucontext_t *'. It would lead to a failure of test-c-stack2.sh.
- dnl If $gl_bogus_si_addr is 1, there is no point to the heuristic.
- case "${host_os}--${host_cpu}--${gl_bogus_si_addr}" in
- linux*--sparc* | *--1)
- gl_cv_sys_xsi_stack_overflow_heuristic=no
- ;;
- *)
- AC_RUN_IFELSE(
- [AC_LANG_SOURCE(
- [[
- #include <unistd.h>
- #include <signal.h>
- #if HAVE_UCONTEXT_H
- # include <ucontext.h>
- #endif
- #if HAVE_SETRLIMIT
- # include <sys/types.h>
- # include <sys/time.h>
- # include <sys/resource.h>
- #endif
- /* In glibc >= 2.34, when _GNU_SOURCE is defined, SIGSTKSZ is
- no longer a compile-time constant. But we need a simple
- constant here. */
- #if __GLIBC__ >= 2
- # undef SIGSTKSZ
- # if defined __ia64__
- # define SIGSTKSZ 262144
- # else
- # define SIGSTKSZ 16384
- # endif
- #endif
- #ifndef SIGSTKSZ
- # define SIGSTKSZ 16384
- #endif
-
- static union
- {
- char buffer[2 * SIGSTKSZ];
- long double ld;
- long u;
- void *p;
- } alternate_signal_stack;
-
- #if STACK_DIRECTION
- # define find_stack_direction(ptr) STACK_DIRECTION
- #else
- static int
- find_stack_direction (char const *addr)
- {
- char dummy;
- return (! addr ? find_stack_direction (&dummy)
- : addr < &dummy ? 1 : -1);
- }
- #endif
-
- static void
- segv_handler (int signo, siginfo_t *info, void *context)
- {
- if (0 < info->si_code)
- {
- /* For XSI heuristics to work, we need uc_stack to
- describe the interrupted stack (as on Solaris), and
- not the currently executing stack (as on Linux). */
- ucontext_t const *user_context = context;
- char const *stack_min = user_context->uc_stack.ss_sp;
- size_t stack_size = user_context->uc_stack.ss_size;
- char const *faulting_address = info->si_addr;
- size_t s = faulting_address - stack_min;
- size_t page_size = sysconf (_SC_PAGESIZE);
- if (find_stack_direction (0) < 0)
- s += page_size;
- if (s < stack_size + page_size)
- _exit (0);
- _exit (4);
- }
- _exit (5);
- }
-
- static int
- c_stack_action ()
- {
- stack_t st;
- struct sigaction act;
- int r;
-
- st.ss_flags = 0;
- /* Use the midpoint to avoid Irix sigaltstack bug. */
- st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ;
- st.ss_size = SIGSTKSZ;
- r = sigaltstack (&st, 0);
- if (r != 0)
- return 1;
-
- sigemptyset (&act.sa_mask);
- act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
- act.sa_sigaction = segv_handler;
- #if FAULT_YIELDS_SIGBUS
- if (sigaction (SIGBUS, &act, 0) < 0)
- return 2;
- #endif
- if (sigaction (SIGSEGV, &act, 0) < 0)
- return 3;
- return 0;
- }
- static volatile int *
- recurse_1 (volatile int n, volatile int *p)
- {
- if (n >= 0)
- *recurse_1 (n + 1, p) += n;
- return p;
- }
- static int
- recurse (volatile int n)
- {
- int sum = 0;
- return *recurse_1 (n, &sum);
- }
- int
- main ()
- {
- int result;
- #if HAVE_SETRLIMIT && defined RLIMIT_STACK
- /* 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);
- #endif
-
- result = c_stack_action ();
- if (result != 0)
- return result;
- return recurse (0);
- }
- ]])],
- [gl_cv_sys_xsi_stack_overflow_heuristic=yes],
- [gl_cv_sys_xsi_stack_overflow_heuristic=no],
- [gl_cv_sys_xsi_stack_overflow_heuristic=cross-compiling])
- ;;
- esac
- ])
-
- if test "$gl_cv_sys_xsi_stack_overflow_heuristic" = yes; then
- AC_DEFINE([HAVE_XSI_STACK_OVERFLOW_HEURISTIC], [1],
- [Define to 1 if extending the stack slightly past the limit causes
- a SIGSEGV, and an alternate stack can be established with sigaltstack,
- and the signal handler is passed a context that specifies the
- run time stack. This behavior is defined by POSIX 1003.1-2001
- with the X/Open System Interface (XSI) option
- and is a standardized way to implement a SEGV-based stack
- overflow detection heuristic.])
- fi
- fi])
-
-
-AC_DEFUN([gl_PREREQ_C_STACK],
- [AC_REQUIRE([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC])
-
- AC_CHECK_FUNCS_ONCE([sigaltstack])
- AC_CHECK_DECLS([sigaltstack], , , [[#include <signal.h>]])
-
- AC_CHECK_HEADERS_ONCE([ucontext.h])
-
- AC_CHECK_TYPES([stack_t], , , [[#include <signal.h>]])
-
- dnl c-stack does not need -lsigsegv if the system has XSI heuristics.
- if test "$gl_cv_sys_xsi_stack_overflow_heuristic" != yes; then
- gl_LIBSIGSEGV
- if test "$gl_cv_lib_sigsegv" = yes; then
- AC_SUBST([LIBCSTACK], [$LIBSIGSEGV])
- AC_SUBST([LTLIBCSTACK], [$LTLIBSIGSEGV])
- fi
- fi
-])
+# serial 23
AC_DEFUN([gl_C_STACK],
[
- dnl Prerequisites of lib/c-stack.c.
- gl_PREREQ_C_STACK
+ dnl 'c-stack' needs -lsigsegv if and only if the 'sigsegv' module needs it.
+ if test "$with_libsigsegv" = yes; then
+ if test "$gl_cv_lib_sigsegv" = yes; then
+ AC_SUBST([LIBCSTACK], [$LIBSIGSEGV])
+ AC_SUBST([LTLIBCSTACK], [$LTLIBSIGSEGV])
+ fi
+ fi
])
diff --git a/modules/c-stack b/modules/c-stack
index 4c80f31..32a4120 100644
--- a/modules/c-stack
+++ b/modules/c-stack
@@ -5,7 +5,6 @@ Files:
lib/c-stack.h
lib/c-stack.c
m4/c-stack.m4
-m4/libsigsegv.m4
Depends-on:
c99
@@ -13,15 +12,10 @@ errno
exitfail
getprogname
gettext-h
-havelib
idx
ignore-value
-intprops
-inttypes
-mempcpy
raise
-sigaction
-stdbool
+sigsegv
stddef
unistd
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: c-stack: Catching stack overflow on most platforms without libsigsegv
2021-05-17 1:49 c-stack: Catching stack overflow on most platforms without libsigsegv Bruno Haible
@ 2021-05-18 6:00 ` Paul Eggert
2021-05-18 17:40 ` Bruno Haible
0 siblings, 1 reply; 3+ messages in thread
From: Paul Eggert @ 2021-05-18 6:00 UTC (permalink / raw)
To: Bruno Haible; +Cc: bug-gnulib
That looks good, thanks. And thanks for all the work with libsigsegv.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: c-stack: Catching stack overflow on most platforms without libsigsegv
2021-05-18 6:00 ` Paul Eggert
@ 2021-05-18 17:40 ` Bruno Haible
0 siblings, 0 replies; 3+ messages in thread
From: Bruno Haible @ 2021-05-18 17:40 UTC (permalink / raw)
To: Paul Eggert; +Cc: bug-gnulib
Paul Eggert wrote:
> That looks good, thanks. And thanks for all the work with libsigsegv.
Pushed.
Bruno
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-05-18 17:41 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-05-17 1:49 c-stack: Catching stack overflow on most platforms without libsigsegv Bruno Haible
2021-05-18 6:00 ` Paul Eggert
2021-05-18 17:40 ` Bruno Haible
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