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      1 /*	$NetBSD: libelf_extended.c,v 1.6 2025/12/25 18:58:13 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 <libelf.h>
     37 
     38 #include "_libelf.h"
     39 
     40 ELFTC_VCSID("Id: libelf_extended.c 4074 2025-01-07 15:34:21Z jkoshy");
     41 
     42 __RCSID("$NetBSD: libelf_extended.c,v 1.6 2025/12/25 18:58:13 jkoshy Exp $");
     43 
     44 /*
     45  * Retrieve section #0, allocating a new section if needed.
     46  */
     47 static Elf_Scn *
     48 _libelf_getscn0(Elf *e)
     49 {
     50 	Elf_Scn *s;
     51 
     52 	if ((s = STAILQ_FIRST(&e->e_u.e_elf.e_scn)) != NULL)
     53 		return (s);
     54 
     55 	return (_libelf_allocate_scn(e, (size_t) SHN_UNDEF));
     56 }
     57 
     58 int
     59 _libelf_setshnum(Elf *e, void *eh, unsigned int ec, size_t shnum)
     60 {
     61 	Elf_Scn *scn;
     62 
     63 	if (shnum >= SHN_LORESERVE) {
     64 		if ((scn = _libelf_getscn0(e)) == NULL)
     65 			return (0);
     66 
     67 		assert(scn->s_ndx == SHN_UNDEF);
     68 
     69 		if (ec == ELFCLASS32)
     70 			scn->s_shdr.s_shdr32.sh_size = (Elf32_Word) shnum;
     71 		else
     72 			scn->s_shdr.s_shdr64.sh_size = shnum;
     73 
     74 		(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
     75 
     76 		shnum = 0;
     77 	}
     78 
     79 	if (ec == ELFCLASS32)
     80 		((Elf32_Ehdr *) eh)->e_shnum = shnum & 0xFFFFU;
     81 	else
     82 		((Elf64_Ehdr *) eh)->e_shnum = shnum & 0xFFFFU;
     83 
     84 
     85 	return (1);
     86 }
     87 
     88 int
     89 _libelf_setshstrndx(Elf *e, void *eh, unsigned int ec, size_t shstrndx)
     90 {
     91 	Elf_Scn *scn;
     92 
     93 	if (shstrndx >= SHN_LORESERVE) {
     94 		if ((scn = _libelf_getscn0(e)) == NULL)
     95 			return (0);
     96 
     97 		assert(scn->s_ndx == SHN_UNDEF);
     98 
     99 		if (ec == ELFCLASS32)
    100 			scn->s_shdr.s_shdr32.sh_link = (Elf32_Word) shstrndx;
    101 		else
    102 			scn->s_shdr.s_shdr64.sh_link = (Elf64_Word) shstrndx;
    103 
    104 		(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
    105 
    106 		shstrndx = SHN_XINDEX;
    107 	}
    108 
    109 	if (ec == ELFCLASS32)
    110 		((Elf32_Ehdr *) eh)->e_shstrndx = shstrndx & 0xFFFFU;
    111 	else
    112 		((Elf64_Ehdr *) eh)->e_shstrndx = shstrndx & 0xFFFFU;
    113 
    114 	return (1);
    115 }
    116 
    117 int
    118 _libelf_setphnum(Elf *e, void *eh, unsigned int ec, size_t phnum)
    119 {
    120 	Elf_Scn *scn;
    121 
    122 	if (phnum >= PN_XNUM) {
    123 		if ((scn = _libelf_getscn0(e)) == NULL)
    124 			return (0);
    125 
    126 		assert(scn->s_ndx == SHN_UNDEF);
    127 
    128 		if (ec == ELFCLASS32)
    129 			scn->s_shdr.s_shdr32.sh_info = (Elf32_Word) phnum;
    130 		else
    131 			scn->s_shdr.s_shdr64.sh_info = (Elf64_Word) phnum;
    132 
    133 		(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
    134 
    135 		phnum = PN_XNUM;
    136 	}
    137 
    138 	if (ec == ELFCLASS32)
    139 		((Elf32_Ehdr *) eh)->e_phnum = phnum & 0xFFFFU;
    140 	else
    141 		((Elf64_Ehdr *) eh)->e_phnum = phnum & 0xFFFFU;
    142 
    143 	return (1);
    144 }
    145