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      1 /*	$NetBSD: gelf_dyn.c,v 1.7 2026/05/17 21:40:50 jkoshy Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2006,2008 Joseph Koshy
      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 #if HAVE_NBTOOL_CONFIG_H
     30 # include "nbtool_config.h"
     31 #endif
     32 
     33 #include <sys/cdefs.h>
     34 
     35 #include <assert.h>
     36 #include <gelf.h>
     37 #include <limits.h>
     38 #include <stdint.h>
     39 
     40 #include "_libelf.h"
     41 
     42 ELFTC_VCSID("Id: gelf_dyn.c 4074 2025-01-07 15:34:21Z jkoshy");
     43 
     44 __RCSID("$NetBSD: gelf_dyn.c,v 1.7 2026/05/17 21:40:50 jkoshy Exp $");
     45 
     46 GElf_Dyn *
     47 gelf_getdyn(Elf_Data *ed, int ndx, GElf_Dyn *dst)
     48 {
     49 	Elf *e;
     50 	size_t msz;
     51 	Elf_Scn *scn;
     52 	unsigned int ec;
     53 	Elf32_Dyn *dyn32;
     54 	Elf64_Dyn *dyn64;
     55 	uint32_t sh_type;
     56 	struct _Libelf_Data *d;
     57 
     58 	d = (struct _Libelf_Data *) ed;
     59 
     60 	if (d == NULL || ndx < 0 || dst == NULL ||
     61 	    (scn = d->d_scn) == NULL ||
     62 	    (e = scn->s_elf) == NULL) {
     63 		LIBELF_SET_ERROR(ARGUMENT, 0);
     64 		return (NULL);
     65 	}
     66 
     67 	ec = e->e_class;
     68 	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
     69 
     70 	if (ec == ELFCLASS32)
     71 		sh_type = scn->s_shdr.s_shdr32.sh_type;
     72 	else
     73 		sh_type = scn->s_shdr.s_shdr64.sh_type;
     74 
     75 	if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
     76 		LIBELF_SET_ERROR(ARGUMENT, 0);
     77 		return (NULL);
     78 	}
     79 
     80 	if ((msz = _libelf_msize(ELF_T_DYN, ec, e->e_version)) == 0)
     81 		return (NULL);
     82 
     83 	assert(ndx >= 0);
     84 
     85 	if (msz * (size_t) ndx >= d->d_data.d_size) {
     86 		LIBELF_SET_ERROR(ARGUMENT, 0);
     87 		return (NULL);
     88 	}
     89 
     90 	if (ec == ELFCLASS32) {
     91 		dyn32 = (Elf32_Dyn *) d->d_data.d_buf + ndx;
     92 
     93 		dst->d_tag      = dyn32->d_tag;
     94 		dst->d_un.d_val = (Elf64_Xword) dyn32->d_un.d_val;
     95 
     96 	} else {
     97 
     98 		dyn64 = (Elf64_Dyn *) d->d_data.d_buf + ndx;
     99 
    100 		*dst = *dyn64;
    101 	}
    102 
    103 	return (dst);
    104 }
    105 
    106 int
    107 gelf_update_dyn(Elf_Data *ed, int ndx, GElf_Dyn *ds)
    108 {
    109 	Elf *e;
    110 	size_t msz;
    111 	Elf_Scn *scn;
    112 	unsigned int ec;
    113 	Elf32_Dyn *dyn32;
    114 	Elf64_Dyn *dyn64;
    115 	uint32_t sh_type;
    116 	struct _Libelf_Data *d;
    117 
    118 	d = (struct _Libelf_Data *) ed;
    119 
    120 	if (d == NULL || ndx < 0 || ds == NULL ||
    121 	    (scn = d->d_scn) == NULL ||
    122 	    (e = scn->s_elf) == NULL) {
    123 		LIBELF_SET_ERROR(ARGUMENT, 0);
    124 		return (0);
    125 	}
    126 
    127 	ec = e->e_class;
    128 	assert(ec == ELFCLASS32 || ec == ELFCLASS64);
    129 
    130 	if (ec == ELFCLASS32)
    131 		sh_type = scn->s_shdr.s_shdr32.sh_type;
    132 	else
    133 		sh_type = scn->s_shdr.s_shdr64.sh_type;
    134 
    135 	if (_libelf_xlate_shtype(sh_type) != ELF_T_DYN) {
    136 		LIBELF_SET_ERROR(ARGUMENT, 0);
    137 		return (0);
    138 	}
    139 
    140 	if ((msz = _libelf_msize(ELF_T_DYN, ec, e->e_version)) == 0)
    141 		return (0);
    142 
    143 	assert(ndx >= 0);
    144 
    145 	if (msz * (size_t) ndx >= d->d_data.d_size) {
    146 		LIBELF_SET_ERROR(ARGUMENT, 0);
    147 		return (0);
    148 	}
    149 
    150 	if (ec == ELFCLASS32) {
    151 		dyn32 = (Elf32_Dyn *) d->d_data.d_buf + ndx;
    152 
    153 		LIBELF_COPY_S32(dyn32, ds, d_tag);
    154 		LIBELF_COPY_U32(dyn32, ds, d_un.d_val);
    155 	} else {
    156 		dyn64 = (Elf64_Dyn *) d->d_data.d_buf + ndx;
    157 
    158 		*dyn64 = *ds;
    159 	}
    160 
    161 	return (1);
    162 }
    163