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/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* SPDX-License-Identifier: MPL-2.0
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/*! \file isc/backtrace.h
* \brief provide a back trace of the running process to help debug problems.
*
* This module tries to get a back trace of the process using some platform
* dependent way when available. It also manages an internal symbol table
* that maps function addresses used in the process to their textual symbols.
* This module is expected to be used to help debug when some fatal error
* happens.
*
* IMPORTANT NOTE: since the (major) intended use case of this module is
* dumping a back trace on a fatal error, normally followed by self termination,
* functions defined in this module generally doesn't employ assertion checks
* (if it did, a program bug could cause infinite recursive calls to a
* backtrace function). These functions still perform minimal checks and return
* ISC_R_FAILURE if they detect an error, but the caller should therefore be
* very careful about the use of these functions, and generally discouraged to
* use them except in an exit path. The exception is
* isc_backtrace_getsymbolfromindex(), which is expected to be used in a
* non-error-handling context and validates arguments with assertion checks.
*/
#ifndef ISC_BACKTRACE_H
#define ISC_BACKTRACE_H 1
/***
*** Imports
***/
#include <isc/types.h>
/***
*** Types
***/
struct isc_backtrace_symmap {
void *addr;
const char *symbol;
};
LIBISC_EXTERNAL_DATA extern const int isc__backtrace_nsymbols;
LIBISC_EXTERNAL_DATA extern const isc_backtrace_symmap_t
isc__backtrace_symtable[];
/***
*** Functions
***/
ISC_LANG_BEGINDECLS
isc_result_t
isc_backtrace_gettrace(void **addrs, int maxaddrs, int *nframes);
/*%<
* Get a back trace of the running process above this function itself. On
* success, addrs[i] will store the address of the call point of the i-th
* stack frame (addrs[0] is the caller of this function). *nframes will store
* the total number of frames.
*
* Requires (note that these are not ensured by assertion checks, see above):
*
*\li 'addrs' is a valid array containing at least 'maxaddrs' void * entries.
*
*\li 'nframes' must be non NULL.
*
* Returns:
*
*\li #ISC_R_SUCCESS
*\li #ISC_R_FAILURE
*\li #ISC_R_NOTFOUND
*\li #ISC_R_NOTIMPLEMENTED
*/
isc_result_t
isc_backtrace_getsymbolfromindex(int index, const void **addrp,
const char **symbolp);
/*%<
* Returns the content of the internal symbol table of the given index.
* On success, *addrsp and *symbolp point to the address and the symbol of
* the 'index'th entry of the table, respectively. If 'index' is not in the
* range of the symbol table, ISC_R_RANGE will be returned.
*
* Requires
*
*\li 'addrp' must be non NULL && '*addrp' == NULL.
*
*\li 'symbolp' must be non NULL && '*symbolp' == NULL.
*
* Returns:
*
*\li #ISC_R_SUCCESS
*\li #ISC_R_RANGE
*/
isc_result_t
isc_backtrace_getsymbol(const void *addr, const char **symbolp,
unsigned long *offsetp);
/*%<
* Searches the internal symbol table for the symbol that most matches the
* given 'addr'. On success, '*symbolp' will point to the name of function
* to which the address 'addr' belong, and '*offsetp' will store the offset
* from the function's entry address to 'addr'.
*
* Requires (note that these are not ensured by assertion checks, see above):
*
*\li 'symbolp' must be non NULL && '*symbolp' == NULL.
*
*\li 'offsetp' must be non NULL.
*
* Returns:
*
*\li #ISC_R_SUCCESS
*\li #ISC_R_FAILURE
*\li #ISC_R_NOTFOUND
*/
ISC_LANG_ENDDECLS
#endif /* ISC_BACKTRACE_H */
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