1 /*-
2  * Copyright (c) 2006,2008 Joseph Koshy
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <assert.h>
28 #include <libelf.h>
29 
30 #include "_libelf.h"
31 
32 ELFTC_VCSID("$Id: libelf_extended.c 3174 2015-03-27 17:13:41Z emaste $");
33 
34 /*
35  * Retrieve section #0, allocating a new section if needed.
36  */
37 static Elf_Scn *
38 _libelf_getscn0(Elf *e)
39 {
40 	Elf_Scn *s;
41 
42 	if ((s = STAILQ_FIRST(&e->e_u.e_elf.e_scn)) != NULL)
43 		return (s);
44 
45 	return (_libelf_allocate_scn(e, (size_t) SHN_UNDEF));
46 }
47 
48 int
49 _libelf_setshnum(Elf *e, void *eh, int ec, size_t shnum)
50 {
51 	Elf_Scn *scn;
52 
53 	if (shnum >= SHN_LORESERVE) {
54 		if ((scn = _libelf_getscn0(e)) == NULL)
55 			return (0);
56 
57 		assert(scn->s_ndx == SHN_UNDEF);
58 
59 		if (ec == ELFCLASS32)
60 			scn->s_shdr.s_shdr32.sh_size = shnum;
61 		else
62 			scn->s_shdr.s_shdr64.sh_size = shnum;
63 
64 		(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
65 
66 		shnum = 0;
67 	}
68 
69 	if (ec == ELFCLASS32)
70 		((Elf32_Ehdr *) eh)->e_shnum = shnum & 0xFFFFU;
71 	else
72 		((Elf64_Ehdr *) eh)->e_shnum = shnum & 0xFFFFU;
73 
74 
75 	return (1);
76 }
77 
78 int
79 _libelf_setshstrndx(Elf *e, void *eh, int ec, size_t shstrndx)
80 {
81 	Elf_Scn *scn;
82 
83 	if (shstrndx >= SHN_LORESERVE) {
84 		if ((scn = _libelf_getscn0(e)) == NULL)
85 			return (0);
86 
87 		assert(scn->s_ndx == SHN_UNDEF);
88 
89 		if (ec == ELFCLASS32)
90 			scn->s_shdr.s_shdr32.sh_link = shstrndx;
91 		else
92 			scn->s_shdr.s_shdr64.sh_link = shstrndx;
93 
94 		(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
95 
96 		shstrndx = SHN_XINDEX;
97 	}
98 
99 	if (ec == ELFCLASS32)
100 		((Elf32_Ehdr *) eh)->e_shstrndx = shstrndx & 0xFFFFU;
101 	else
102 		((Elf64_Ehdr *) eh)->e_shstrndx = shstrndx & 0xFFFFU;
103 
104 	return (1);
105 }
106 
107 int
108 _libelf_setphnum(Elf *e, void *eh, int ec, size_t phnum)
109 {
110 	Elf_Scn *scn;
111 
112 	if (phnum >= PN_XNUM) {
113 		if ((scn = _libelf_getscn0(e)) == NULL)
114 			return (0);
115 
116 		assert(scn->s_ndx == SHN_UNDEF);
117 
118 		if (ec == ELFCLASS32)
119 			scn->s_shdr.s_shdr32.sh_info = phnum;
120 		else
121 			scn->s_shdr.s_shdr64.sh_info = phnum;
122 
123 		(void) elf_flagshdr(scn, ELF_C_SET, ELF_F_DIRTY);
124 
125 		phnum = PN_XNUM;
126 	}
127 
128 	if (ec == ELFCLASS32)
129 		((Elf32_Ehdr *) eh)->e_phnum = phnum & 0xFFFFU;
130 	else
131 		((Elf64_Ehdr *) eh)->e_phnum = phnum & 0xFFFFU;
132 
133 	return (1);
134 }
135