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      1 /*-
      2  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      3  * All rights reserved.
      4  *
      5  * This code is derived from software contributed to The NetBSD Foundation
      6  * by Matt Thomas of 3am Software Foundry.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     19  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     20  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     21  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     27  * POSSIBILITY OF SUCH DAMAGE.
     28  */
     29 
     30 #include <sys/cdefs.h>
     31 #ifndef lint
     32 __RCSID("$NetBSD: find_exidx.c,v 1.4 2014/08/10 23:35:27 matt Exp $");
     33 #endif /* not lint */
     34 
     35 #include "debug.h"
     36 #include "rtld.h"
     37 
     38 #if defined(__ARM_EABI__) && !defined(__ARM_DWARF_EH__)
     39 
     40 _Unwind_Ptr
     41 __gnu_Unwind_Find_exidx(_Unwind_Ptr pc, int * pcount)
     42 {
     43 	const Obj_Entry *obj;
     44 	_Unwind_Ptr start = NULL;
     45 	int count = 0;
     46 
     47 	dbg(("__gnu_Unwind_Find_exidx"));
     48 
     49 	_rtld_shared_enter();
     50 
     51 	vaddr_t va = (vaddr_t)pc;
     52 	for (obj = _rtld_objlist; obj != NULL; obj = obj->next) {
     53 		/*
     54 		 * If the address we are looking for is inside this object,
     55 		 * we've found the object to inspect.
     56 		 */
     57 		if ((vaddr_t)obj->mapbase <= va
     58 		    && va < (vaddr_t)obj->mapbase + obj->mapsize)
     59 			break;
     60 	}
     61 
     62 	/*
     63 	 * If we found an object and it has some exception data, we
     64 	 * need to see if the address matches a PT_LOAD section.
     65 	 */
     66 	if (obj != NULL && obj->exidx_start != NULL) {
     67 		va -= (vaddr_t)obj->relocbase;
     68 		const Elf_Phdr *ph = obj->phdr;
     69 		const Elf_Phdr * const phlimit = ph + obj->phsize / sizeof(*ph);
     70 		for (; ph < phlimit; ph++) {
     71 			if (ph->p_type == PT_LOAD
     72 			    && ph->p_vaddr <= va
     73 			    && va < ph->p_vaddr + ph->p_memsz) {
     74 				count = obj->exidx_sz / 8;
     75 				start = obj->exidx_start;
     76 				break;
     77 			}
     78 		}
     79 	}
     80 
     81 	_rtld_shared_exit();
     82 
     83 	/*
     84 	 * deal with the return values.
     85 	 */
     86 	*pcount = count;
     87 	return start;
     88 }
     89 
     90 #endif
     91