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      1 /*	$NetBSD: libdwarf_loclist.c,v 1.5 2024/03/03 17:37:32 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2009,2011 Kai Wang
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include "_libdwarf.h"
     30 
     31 __RCSID("$NetBSD: libdwarf_loclist.c,v 1.5 2024/03/03 17:37:32 christos Exp $");
     32 ELFTC_VCSID("Id: libdwarf_loclist.c 3061 2014-06-02 00:42:41Z kaiwang27");
     33 
     34 static int
     35 _dwarf_loclist_add_locdesc(Dwarf_Debug dbg, Dwarf_CU cu, Dwarf_Section *ds,
     36     Dwarf_Unsigned *off, Dwarf_Locdesc **ld, Dwarf_Signed *ldlen,
     37     Dwarf_Unsigned *total_len, Dwarf_Error *error)
     38 {
     39 	uint64_t start, end;
     40 	int i, len, ret;
     41 
     42 	if (total_len != NULL)
     43 		*total_len = 0;
     44 
     45 	for (i = 0; *off < ds->ds_size; i++) {
     46 		start = dbg->read(ds->ds_data, off, cu->cu_pointer_size);
     47 		end = dbg->read(ds->ds_data, off, cu->cu_pointer_size);
     48 		if (ld != NULL) {
     49 			ld[i]->ld_lopc = start;
     50 			ld[i]->ld_hipc = end;
     51 		}
     52 
     53 		if (total_len != NULL)
     54 			*total_len += 2 * cu->cu_pointer_size;
     55 
     56 		/* Check if it is the end entry. */
     57 		if (start == 0 && end ==0) {
     58 			i++;
     59 			break;
     60 		}
     61 
     62 		/* Check if it is base-select entry. */
     63 		if ((cu->cu_pointer_size == 4 && start == ~0U) ||
     64 		    (cu->cu_pointer_size == 8 && start == ~0ULL))
     65 			continue;
     66 
     67 		/* Otherwise it's normal entry. */
     68 		len = dbg->read(ds->ds_data, off, 2);
     69 		if (*off + len > ds->ds_size) {
     70 			DWARF_SET_ERROR(dbg, error,
     71 			    DW_DLE_DEBUG_LOC_SECTION_SHORT);
     72 			return (DW_DLE_DEBUG_LOC_SECTION_SHORT);
     73 		}
     74 
     75 		if (total_len != NULL)
     76 			*total_len += len;
     77 
     78 		if (ld != NULL) {
     79 			ret = _dwarf_loc_fill_locdesc(dbg, ld[i],
     80 			    ds->ds_data + *off, len, cu->cu_pointer_size,
     81 			    cu->cu_length_size == 4 ? 4 : 8, cu->cu_version,
     82 			    error);
     83 			if (ret != DW_DLE_NONE)
     84 				return (ret);
     85 		}
     86 
     87 		*off += len;
     88 	}
     89 
     90 	if (ldlen != NULL)
     91 		*ldlen = i;
     92 
     93 	return (DW_DLE_NONE);
     94 }
     95 
     96 int
     97 _dwarf_loclist_find(Dwarf_Debug dbg, Dwarf_CU cu, uint64_t lloff,
     98     Dwarf_Locdesc ***ret_llbuf, Dwarf_Signed *listlen,
     99     Dwarf_Unsigned *entry_len, Dwarf_Error *error)
    100 {
    101 	Dwarf_Locdesc **llbuf;
    102 	Dwarf_Section *ds;
    103 	Dwarf_Signed ldlen;
    104 	Dwarf_Unsigned off;
    105 	int i, ret;
    106 
    107 	if ((ds = _dwarf_find_section(dbg, ".debug_loc")) == NULL) {
    108 		DWARF_SET_ERROR(dbg, error, DW_DLE_NO_ENTRY);
    109 		return (DW_DLE_NO_ENTRY);
    110 	}
    111 
    112 	if (lloff >= ds->ds_size) {
    113 		DWARF_SET_ERROR(dbg, error, DW_DLE_NO_ENTRY);
    114 		return (DW_DLE_NO_ENTRY);
    115 	}
    116 
    117 	/* Get the number of locdesc the first round. */
    118 	off = lloff;
    119 	ret = _dwarf_loclist_add_locdesc(dbg, cu, ds, &off, NULL, &ldlen,
    120 	    NULL, error);
    121 	if (ret != DW_DLE_NONE)
    122 		return (ret);
    123 
    124 	if (ldlen == 0)
    125 		return (DW_DLE_NO_ENTRY);
    126 
    127 	/*
    128 	 * Dwarf_Locdesc list memory is allocated in this way (one more level
    129 	 * of indirect) to make the loclist API be compatible with SGI libdwarf.
    130 	 */
    131 	if ((llbuf = calloc(ldlen, sizeof(Dwarf_Locdesc *))) == NULL) {
    132 		DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
    133 		return (DW_DLE_MEMORY);
    134 	}
    135 	for (i = 0; i < ldlen; i++) {
    136 		if ((llbuf[i] = calloc(1, sizeof(Dwarf_Locdesc))) == NULL) {
    137 			DWARF_SET_ERROR(dbg, error, DW_DLE_MEMORY);
    138 			ret = DW_DLE_MEMORY;
    139 			goto fail_cleanup;
    140 		}
    141 	}
    142 
    143 	off = lloff;
    144 
    145 	/* Fill in locdesc. */
    146 	ret = _dwarf_loclist_add_locdesc(dbg, cu, ds, &off, llbuf, NULL,
    147 	    entry_len, error);
    148 	if (ret != DW_DLE_NONE)
    149 		goto fail_cleanup;
    150 
    151 	*ret_llbuf = llbuf;
    152 	*listlen = ldlen;
    153 
    154 	return (DW_DLE_NONE);
    155 
    156 fail_cleanup:
    157 
    158 	if (llbuf != NULL) {
    159 		for (i = 0; i < ldlen; i++) {
    160 			if (llbuf[i]->ld_s)
    161 				free(llbuf[i]->ld_s);
    162 			free(llbuf[i]);
    163 		}
    164 		free(llbuf);
    165 	}
    166 
    167 	return (ret);
    168 }
    169