| Current File : //usr/include/sigsegv.h |
/* Page fault handling library.
Copyright (C) 1998-1999, 2002, 2004-2008 Bruno Haible <bruno@clisp.org>
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#ifndef _SIGSEGV_H
#define _SIGSEGV_H
#include <ucontext.h>
/* HAVE_SIGSEGV_RECOVERY
is defined if the system supports catching SIGSEGV. */
#if 1
# define HAVE_SIGSEGV_RECOVERY 1
#endif
/* HAVE_STACK_OVERFLOW_RECOVERY
is defined if stack overflow can be caught. */
#if 1
# define HAVE_STACK_OVERFLOW_RECOVERY 1
#endif
#ifdef __cplusplus
extern "C" {
#endif
#define LIBSIGSEGV_VERSION 0x0206 /* version number: (major<<8) + minor */
extern int libsigsegv_version; /* Likewise */
/* -------------------------------------------------------------------------- */
/*
* The type of a global SIGSEGV handler.
* The fault address is passed as argument.
* The access type (read access or write access) is not passed; your handler
* has to know itself how to distinguish these two cases.
* The second argument is 0, meaning it could also be a stack overflow, or 1,
* meaning the handler should seriously try to fix the fault.
* The return value should be nonzero if the handler has done its job
* and no other handler should be called, or 0 if the handler declines
* responsibility for the given address.
*
* The handler is run at a moment when nothing about the global state of the
* program is known. Therefore it cannot use facilities that manipulate global
* variables or locks. In particular, it cannot use malloc(); use mmap()
* instead. It cannot use fopen(); use open() instead. Etc. All global
* variables that are accessed by the handler should be marked 'volatile'.
*/
typedef int (*sigsegv_handler_t) (void* fault_address, int serious);
/*
* Installs a global SIGSEGV handler.
* This should be called once only, and it ignores any previously installed
* SIGSEGV handler.
* Returns 0 on success, or -1 if the system doesn't support catching SIGSEGV.
*/
extern int sigsegv_install_handler (sigsegv_handler_t handler);
/*
* Deinstalls the global SIGSEGV handler.
* This goes back to the state where no SIGSEGV handler is installed.
*/
extern void sigsegv_deinstall_handler (void);
#if LIBSIGSEGV_VERSION >= 0x0206
/*
* Prepares leaving a SIGSEGV handler (through longjmp or similar means).
* Control is transferred by calling CONTINUATION with CONT_ARG1, CONT_ARG2,
* CONT_ARG3 as arguments.
* CONTINUATION must not return.
* The sigsegv_leave_handler function may return if called from a SIGSEGV
* handler; its return value should be used as the handler's return value.
* The sigsegv_leave_handler function does not return if called from a
* stack overflow handler.
*/
extern int sigsegv_leave_handler (void (*continuation) (void*, void*, void*), void* cont_arg1, void* cont_arg2, void* cont_arg3);
#else /* older versions of libsigsegv */
/*
* Prepares leaving a SIGSEGV handler (through longjmp or similar means).
* Limitation: This function could only be called once on MacOS X.
*/
extern void sigsegv_leave_handler (void);
#endif
/*
* The type of a context passed to a stack overflow handler.
* This type is system dependent; on some platforms it is an 'ucontext_t *',
* on some platforms it is a 'struct sigcontext *', on others merely an
* opaque 'void *'.
*/
typedef ucontext_t *stackoverflow_context_t;
/*
* The type of a stack overflow handler.
* Such a handler should perform a longjmp call in order to reduce the amount
* of stack needed. It must not return.
* The emergency argument is 0 when the stack could be repared, or 1 if the
* application should better save its state and exit now.
*
* The handler is run at a moment when nothing about the global state of the
* program is known. Therefore it cannot use facilities that manipulate global
* variables or locks. In particular, it cannot use malloc(); use mmap()
* instead. It cannot use fopen(); use open() instead. Etc. All global
* variables that are accessed by the handler should be marked 'volatile'.
*/
typedef void (*stackoverflow_handler_t) (int emergency, stackoverflow_context_t scp);
/*
* Installs a stack overflow handler.
* The extra_stack argument is a pointer to a pre-allocated area used as a
* stack for executing the handler. It is typically allocated by use of
* `alloca' during `main'. Its size should be sufficiently large.
* The following code determines an appropriate size:
* #include <signal.h>
* #ifndef SIGSTKSZ / * glibc defines SIGSTKSZ for this purpose * /
* # define SIGSTKSZ 16384 / * on most platforms, 16 KB are sufficient * /
* #endif
* Returns 0 on success, or -1 if the system doesn't support catching stack
* overflow.
*/
extern int stackoverflow_install_handler (stackoverflow_handler_t handler,
void* extra_stack, unsigned long extra_stack_size);
/*
* Deinstalls the stack overflow handler.
*/
extern void stackoverflow_deinstall_handler (void);
/* -------------------------------------------------------------------------- */
/*
* The following structure and functions permit to define different SIGSEGV
* policies on different address ranges.
*/
/*
* The type of a local SIGSEGV handler.
* The fault address is passed as argument.
* The second argument is fixed arbitrary user data.
* The return value should be nonzero if the handler has done its job
* and no other handler should be called, or 0 if the handler declines
* responsibility for the given address.
*/
typedef int (*sigsegv_area_handler_t) (void* fault_address, void* user_arg);
/*
* This structure represents a table of memory areas (address range intervals),
* with an local SIGSEGV handler for each.
*/
typedef
struct sigsegv_dispatcher {
void* tree;
}
sigsegv_dispatcher;
/*
* Initializes a sigsegv_dispatcher structure.
*/
extern void sigsegv_init (sigsegv_dispatcher* dispatcher);
/*
* Adds a local SIGSEGV handler to a sigsegv_dispatcher structure.
* It will cover the interval [address..address+len-1].
* Returns a "ticket" that can be used to remove the handler later.
*/
extern void* sigsegv_register (sigsegv_dispatcher* dispatcher,
void* address, unsigned long len,
sigsegv_area_handler_t handler, void* handler_arg);
/*
* Removes a local SIGSEGV handler.
*/
extern void sigsegv_unregister (sigsegv_dispatcher* dispatcher, void* ticket);
/*
* Call the local SIGSEGV handler responsible for the given fault address.
* Return the handler's return value. 0 means that no handler has been found,
* or that a handler was found but declined responsibility.
*/
extern int sigsegv_dispatch (sigsegv_dispatcher* dispatcher, void* fault_address);
/* -------------------------------------------------------------------------- */
#ifdef __cplusplus
}
#endif
#endif /* _SIGSEGV_H */