/
niceSOFT
/
diffutils
Обзор
Документация
Войти
/
niceSOFT
/
diffutils
Код
Задачи
Вики
Пакеты
0
Релизы
0
Аналитика
Безопасность
v2.8
lib/c-stack.c
237 строк
6 KB
Paul Eggert
(c_stack_die) [!HAVE_SIGINFO_T]: Don't use info.
24 мар 2002, 10:36
24 мар 2002, 10:36
78899f4
Код
Авторство
О чём код?
/* Stack overflow handling. Copyright (C) 2002 Free Software Foundation, Inc. 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. This program 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 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. */ /* Written by Paul Eggert. */ /* This module assumes that each stack frame is smaller than a page. If you use alloca, dynamic arrays, or large local variables, your program may extend the stack by more than a page at a time. If so, the code below may incorrectly report a program error, or worse yet, may not detect the overflow at all. To avoid this problem, don't use large local arrays. */ #if HAVE_CONFIG_H # include <config.h> #endif #include "gettext.h" #define _(msgid) gettext (msgid) #include <errno.h> #ifndef ENOTSUP # define ENOTSUP EINVAL #endif #if HAVE_INTTYPES_H # include <inttypes.h> #else # if HAVE_STDINT_H # include <stdint.h> # endif #endif #include <signal.h> #include <stdlib.h> #include <string.h> #if HAVE_UNISTD_H # include <unistd.h> #endif #ifndef STDERR_FILENO # define STDERR_FILENO 2 #endif #include "c-stack.h" #include "exitfail.h" extern char *program_name; #if HAVE_XSI_STACK_OVERFLOW_HEURISTIC # include <ucontext.h> /* 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; uintmax_t u; void *p; } alternate_signal_stack; /* Direction of the C runtime stack. This function is async-signal-safe. */ # 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 /* The SIGSEGV handler. */ static void (* volatile segv_action) (int, siginfo_t *, void *); /* Handle a segmentation violation and exit. This function is async-signal-safe. */ static void segv_handler (int signo, siginfo_t *info, void *context) { /* Clear SIGNO if it seems to have been a stack overflow. */ 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. */ 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) signo = 0; } segv_action (signo, info, context); } #endif /* HAVE_XSI_STACK_OVERFLOW_HEURISTIC */ /* Translated messages for program errors and stack overflow. Do not translate them in the signal handler, since gettext is not async-signal-safe. */ static char const * volatile program_error_message; static char const * volatile stack_overflow_message; /* 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. */ void c_stack_die (int signo, siginfo_t *info, void *context) { char const *message = signo ? program_error_message : stack_overflow_message; write (STDERR_FILENO, program_name, strlen (program_name)); write (STDERR_FILENO, ": ", 2); write (STDERR_FILENO, message, strlen (message)); write (STDERR_FILENO, "\n", 1); if (! signo) _exit (exit_failure); #if HAVE_SIGINFO_T if (context && info && 0 <= info->si_code) { /* Re-raise the exception at the same address. */ char *addr = info->si_addr; *addr = 0; } #endif kill (getpid (), signo); } /* Set up ACTION so that it is invoked on C stack overflow. Return -1 (setting errno) if this cannot be done. ACTION must invoke only async-signal-safe functions. ACTION together with its callees must not require more than SIGSTKSZ bytes of stack space. */ int c_stack_action (void (*action) (int, siginfo_t *, void *)) { #if ! HAVE_XSI_STACK_OVERFLOW_HEURISTIC errno = ENOTSUP; return -1; #else struct sigaction act; stack_t st; int r; st.ss_flags = 0; st.ss_sp = alternate_signal_stack.buffer; st.ss_size = sizeof alternate_signal_stack.buffer; r = sigaltstack (&st, 0); if (r != 0) return r; program_error_message = _("program error"); stack_overflow_message = _("stack overflow"); segv_action = action; 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; return sigaction (SIGSEGV, &act, 0); #endif } #if DEBUG #include <stdio.h> 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, char **argv) { program_name = argv[0]; c_stack_action (c_stack_die); return recurse ("\1"); } #endif /* DEBUG */ /* Local Variables: compile-command: "gcc -D_GNU_SOURCE -DDEBUG \ -DHAVE_INTTYPES_H -DHAVE_SIGINFO_T \ -DHAVE_XSI_STACK_OVERFLOW_HEURISTIC -DHAVE_UNISTD_H \ -Wall -W -g c-stack.c -o c-stack" End: */