1 /* Free resources associated with Elf descriptor.
2 Copyright (C) 1998,1999,2000,2001,2002,2004,2005,2007,2015,2016 Red Hat, Inc.
3 This file is part of elfutils.
4 Written by Ulrich Drepper <drepper@redhat.com>, 1998.
5
6 This file is free software; you can redistribute it and/or modify
7 it under the terms of either
8
9 * the GNU Lesser General Public License as published by the Free
10 Software Foundation; either version 3 of the License, or (at
11 your option) any later version
12
13 or
14
15 * the GNU General Public License as published by the Free
16 Software Foundation; either version 2 of the License, or (at
17 your option) any later version
18
19 or both in parallel, as here.
20
21 elfutils is distributed in the hope that it will be useful, but
22 WITHOUT ANY WARRANTY; without even the implied warranty of
23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 General Public License for more details.
25
26 You should have received copies of the GNU General Public License and
27 the GNU Lesser General Public License along with this program. If
28 not, see <http://www.gnu.org/licenses/>. */
29
30 #ifdef HAVE_CONFIG_H
31 # include <config.h>
32 #endif
33
34 #include <assert.h>
35 #include <stddef.h>
36 #include <stdlib.h>
37 #include <sys/mman.h>
38
39 #include "libelfP.h"
40
41
42 int
elf_end(Elf * elf)43 elf_end (Elf *elf)
44 {
45 Elf *parent;
46
47 if (elf == NULL)
48 /* This is allowed and is a no-op. */
49 return 0;
50
51 /* Make sure we are alone. */
52 rwlock_wrlock (elf->lock);
53
54 if (elf->ref_count != 0 && --elf->ref_count != 0)
55 {
56 /* Not yet the last activation. */
57 int result = elf->ref_count;
58 rwlock_unlock (elf->lock);
59 return result;
60 }
61
62 if (elf->kind == ELF_K_AR)
63 {
64 /* We cannot remove the descriptor now since we still have some
65 descriptors which depend on it. But we can free the archive
66 symbol table since this is only available via the archive ELF
67 descriptor. The long name table cannot be freed yet since
68 the archive headers for the ELF files in the archive point
69 into this array. */
70 if (elf->state.ar.ar_sym != (Elf_Arsym *) -1l)
71 free (elf->state.ar.ar_sym);
72 elf->state.ar.ar_sym = NULL;
73
74 if (elf->state.ar.children != NULL)
75 return 0;
76 }
77
78 /* Remove this structure from the children list. */
79 parent = elf->parent;
80 if (parent != NULL)
81 {
82 /* This is tricky. Lock must be acquire from the father to
83 the child but here we already have the child lock. We
84 solve this problem by giving free the child lock. The
85 state of REF_COUNT==0 is handled all over the library, so
86 this should be ok. */
87 rwlock_unlock (elf->lock);
88 rwlock_rdlock (parent->lock);
89 rwlock_wrlock (elf->lock);
90
91 if (parent->state.ar.children == elf)
92 parent->state.ar.children = elf->next;
93 else
94 {
95 struct Elf *child = parent->state.ar.children;
96
97 while (child->next != elf)
98 child = child->next;
99
100 child->next = elf->next;
101 }
102
103 rwlock_unlock (parent->lock);
104 }
105
106 /* This was the last activation. Free all resources. */
107 switch (elf->kind)
108 {
109 case ELF_K_AR:
110 if (elf->state.ar.long_names != NULL)
111 free (elf->state.ar.long_names);
112 break;
113
114 case ELF_K_ELF:
115 {
116 Elf_Data_Chunk *rawchunks
117 = (elf->class == ELFCLASS32
118 || (offsetof (struct Elf, state.elf32.rawchunks)
119 == offsetof (struct Elf, state.elf64.rawchunks))
120 ? elf->state.elf32.rawchunks
121 : elf->state.elf64.rawchunks);
122 while (rawchunks != NULL)
123 {
124 Elf_Data_Chunk *next = rawchunks->next;
125 if (rawchunks->dummy_scn.flags & ELF_F_MALLOCED)
126 free (rawchunks->data.d.d_buf);
127 free (rawchunks);
128 rawchunks = next;
129 }
130
131 Elf_ScnList *list = (elf->class == ELFCLASS32
132 || (offsetof (struct Elf, state.elf32.scns)
133 == offsetof (struct Elf, state.elf64.scns))
134 ? &elf->state.elf32.scns
135 : &elf->state.elf64.scns);
136
137 do
138 {
139 /* Free all separately allocated section headers. */
140 size_t cnt = list->max;
141
142 while (cnt-- > 0)
143 {
144 /* These pointers can be NULL; it's safe to use
145 'free' since it will check for this. */
146 Elf_Scn *scn = &list->data[cnt];
147 Elf_Data_List *runp;
148
149 if ((scn->shdr_flags & ELF_F_MALLOCED) != 0)
150 /* It doesn't matter which pointer. */
151 free (scn->shdr.e32);
152
153 /* Free zdata if uncompressed, but not yet used as
154 rawdata_base. If it is already used it will be
155 freed below. */
156 if (scn->zdata_base != scn->rawdata_base)
157 free (scn->zdata_base);
158
159 /* If the file has the same byte order and the
160 architecture doesn't require overly stringent
161 alignment the raw data buffer is the same as the
162 one used for presenting to the caller. */
163 if (scn->data_base != scn->rawdata_base)
164 free (scn->data_base);
165
166 /* The section data is allocated if we couldn't mmap
167 the file. Or if we had to decompress. */
168 if (elf->map_address == NULL
169 || scn->rawdata_base == scn->zdata_base
170 || (scn->flags & ELF_F_MALLOCED) != 0)
171 free (scn->rawdata_base);
172
173 /* Free the list of data buffers for the section.
174 We don't free the buffers themselves since this
175 is the users job. */
176 runp = scn->data_list.next;
177 while (runp != NULL)
178 {
179 Elf_Data_List *oldp = runp;
180 runp = runp->next;
181 if ((oldp->flags & ELF_F_MALLOCED) != 0)
182 free (oldp);
183 }
184 }
185
186 /* Free the memory for the array. */
187 Elf_ScnList *oldp = list;
188 list = list->next;
189 assert (list == NULL || oldp->cnt == oldp->max);
190 if (oldp != (elf->class == ELFCLASS32
191 || (offsetof (struct Elf, state.elf32.scns)
192 == offsetof (struct Elf, state.elf64.scns))
193 ? &elf->state.elf32.scns
194 : &elf->state.elf64.scns))
195 free (oldp);
196 }
197 while (list != NULL);
198 }
199
200 /* Free the section header. */
201 if (elf->state.elf.shdr_malloced != 0)
202 free (elf->class == ELFCLASS32
203 || (offsetof (struct Elf, state.elf32.shdr)
204 == offsetof (struct Elf, state.elf64.shdr))
205 ? (void *) elf->state.elf32.shdr
206 : (void *) elf->state.elf64.shdr);
207
208 /* Free the program header. */
209 if ((elf->state.elf.phdr_flags & ELF_F_MALLOCED) != 0)
210 free (elf->class == ELFCLASS32
211 || (offsetof (struct Elf, state.elf32.phdr)
212 == offsetof (struct Elf, state.elf64.phdr))
213 ? (void *) elf->state.elf32.phdr
214 : (void *) elf->state.elf64.phdr);
215 break;
216
217 default:
218 break;
219 }
220
221 if (elf->map_address != NULL && parent == NULL)
222 {
223 /* The file was read or mapped for this descriptor. */
224 if ((elf->flags & ELF_F_MALLOCED) != 0)
225 free (elf->map_address);
226 else if ((elf->flags & ELF_F_MMAPPED) != 0)
227 munmap (elf->map_address, elf->maximum_size);
228 }
229
230 rwlock_unlock (elf->lock);
231 rwlock_fini (elf->lock);
232
233 /* Finally the descriptor itself. */
234 free (elf);
235
236 return (parent != NULL && parent->ref_count == 0
237 ? INTUSE(elf_end) (parent) : 0);
238 }
239 INTDEF(elf_end)
240