1 /*
2 opt.delscn.c - implementation of the elf_delscn(3) function.
3 Copyright (C) 1995 - 2001 Michael Riepe
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
18 */
19
20 #include <private.h>
21
22 #ifndef lint
23 static const char rcsid[] = "@(#) $Id: opt.delscn.c,v 1.12 2008/05/23 08:15:35 michael Exp $";
24 #endif /* lint */
25
26 static size_t
_newindex(size_t old,size_t index)27 _newindex(size_t old, size_t index) {
28 return old == index ? SHN_UNDEF : (old > index ? old - 1 : old);
29 }
30
31 static void
_elf32_update_shdr(Elf * elf,size_t index)32 _elf32_update_shdr(Elf *elf, size_t index) {
33 Elf32_Shdr *shdr;
34 Elf_Scn *scn;
35
36 ((Elf32_Ehdr*)elf->e_ehdr)->e_shnum = elf->e_scn_n->s_index + 1;
37 for (scn = elf->e_scn_1; scn; scn = scn->s_link) {
38 shdr = &scn->s_shdr32;
39 switch (shdr->sh_type) {
40 case SHT_REL:
41 case SHT_RELA:
42 shdr->sh_info = _newindex(shdr->sh_info, index);
43 /* fall through */
44 case SHT_DYNSYM:
45 case SHT_DYNAMIC:
46 case SHT_HASH:
47 case SHT_SYMTAB:
48 #if __LIBELF_SYMBOL_VERSIONS
49 #if __LIBELF_SUN_SYMBOL_VERSIONS
50 case SHT_SUNW_verdef:
51 case SHT_SUNW_verneed:
52 case SHT_SUNW_versym:
53 #else /* __LIBELF_SUN_SYMBOL_VERSIONS */
54 case SHT_GNU_verdef:
55 case SHT_GNU_verneed:
56 case SHT_GNU_versym:
57 #endif /* __LIBELF_SUN_SYMBOL_VERSIONS */
58 #endif /* __LIBELF_SYMBOL_VERSIONS */
59 shdr->sh_link = _newindex(shdr->sh_link, index);
60 /* fall through */
61 default:
62 break;
63 }
64 }
65 }
66
67 #if __LIBELF64
68
69 static void
_elf64_update_shdr(Elf * elf,size_t index)70 _elf64_update_shdr(Elf *elf, size_t index) {
71 Elf64_Shdr *shdr;
72 Elf_Scn *scn;
73
74 ((Elf64_Ehdr*)elf->e_ehdr)->e_shnum = elf->e_scn_n->s_index + 1;
75 for (scn = elf->e_scn_1; scn; scn = scn->s_link) {
76 shdr = &scn->s_shdr64;
77 switch (shdr->sh_type) {
78 case SHT_REL:
79 case SHT_RELA:
80 shdr->sh_info = _newindex(shdr->sh_info, index);
81 /* fall through */
82 case SHT_DYNSYM:
83 case SHT_DYNAMIC:
84 case SHT_HASH:
85 case SHT_SYMTAB:
86 #if __LIBELF_SYMBOL_VERSIONS
87 #if __LIBELF_SUN_SYMBOL_VERSIONS
88 case SHT_SUNW_verdef:
89 case SHT_SUNW_verneed:
90 case SHT_SUNW_versym:
91 #else /* __LIBELF_SUN_SYMBOL_VERSIONS */
92 case SHT_GNU_verdef:
93 case SHT_GNU_verneed:
94 case SHT_GNU_versym:
95 #endif /* __LIBELF_SUN_SYMBOL_VERSIONS */
96 #endif /* __LIBELF_SYMBOL_VERSIONS */
97 shdr->sh_link = _newindex(shdr->sh_link, index);
98 /* fall through */
99 default:
100 break;
101 }
102 }
103 }
104
105 #endif /* __LIBELF64 */
106
107 size_t
elf_delscn(Elf * elf,Elf_Scn * scn)108 elf_delscn(Elf *elf, Elf_Scn *scn) {
109 Elf_Scn *pscn;
110 Scn_Data *sd;
111 Scn_Data *tmp;
112 size_t index;
113
114 if (!elf || !scn) {
115 return SHN_UNDEF;
116 }
117 elf_assert(elf->e_magic == ELF_MAGIC);
118 elf_assert(scn->s_magic == SCN_MAGIC);
119 elf_assert(elf->e_ehdr);
120 if (scn->s_elf != elf) {
121 seterr(ERROR_ELFSCNMISMATCH);
122 return SHN_UNDEF;
123 }
124 elf_assert(elf->e_scn_1);
125 if (scn == elf->e_scn_1) {
126 seterr(ERROR_NULLSCN);
127 return SHN_UNDEF;
128 }
129
130 /*
131 * Find previous section.
132 */
133 for (pscn = elf->e_scn_1; pscn->s_link; pscn = pscn->s_link) {
134 if (pscn->s_link == scn) {
135 break;
136 }
137 }
138 if (pscn->s_link != scn) {
139 seterr(ERROR_ELFSCNMISMATCH);
140 return SHN_UNDEF;
141 }
142 /*
143 * Unlink section.
144 */
145 if (elf->e_scn_n == scn) {
146 elf->e_scn_n = pscn;
147 }
148 pscn->s_link = scn->s_link;
149 index = scn->s_index;
150 /*
151 * Free section descriptor and data.
152 */
153 for (sd = scn->s_data_1; sd; sd = tmp) {
154 elf_assert(sd->sd_magic == DATA_MAGIC);
155 elf_assert(sd->sd_scn == scn);
156 tmp = sd->sd_link;
157 if (sd->sd_free_data && sd->sd_memdata) {
158 free(sd->sd_memdata);
159 }
160 if (sd->sd_freeme) {
161 free(sd);
162 }
163 }
164 if ((sd = scn->s_rawdata)) {
165 elf_assert(sd->sd_magic == DATA_MAGIC);
166 elf_assert(sd->sd_scn == scn);
167 if (sd->sd_free_data && sd->sd_memdata) {
168 free(sd->sd_memdata);
169 }
170 if (sd->sd_freeme) {
171 free(sd);
172 }
173 }
174 if (scn->s_freeme) {
175 elf_assert(scn->s_index > 0);
176 free(scn);
177 }
178 /*
179 * Adjust section indices.
180 */
181 for (scn = pscn->s_link; scn; scn = scn->s_link) {
182 elf_assert(scn->s_index > index);
183 scn->s_index--;
184 }
185 /*
186 * Adjust ELF header and well-known section headers.
187 */
188 if (elf->e_class == ELFCLASS32) {
189 _elf32_update_shdr(elf, index);
190 return index;
191 }
192 #if __LIBELF64
193 else if (elf->e_class == ELFCLASS64) {
194 _elf64_update_shdr(elf, index);
195 return index;
196 }
197 #endif /* __LIBELF64 */
198 else if (valid_class(elf->e_class)) {
199 seterr(ERROR_UNIMPLEMENTED);
200 }
201 else {
202 seterr(ERROR_UNKNOWN_CLASS);
203 }
204 return SHN_UNDEF;
205 }
206