summaryrefslogtreecommitdiffstats
path: root/libelf/elf_end.c
blob: 7ea876c32ab0c980b3c517bbe4c822f47b0eb1ce (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
/* Free resources associated with Elf descriptor.
   Copyright (C) 1998,1999,2000,2001,2002,2004,2005,2007,2015 Red Hat, Inc.
   This file is part of elfutils.
   Written by Ulrich Drepper <drepper@redhat.com>, 1998.

   This file is free software; you can redistribute it and/or modify
   it under the terms of either

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at
       your option) any later version

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at
       your option) any later version

   or both in parallel, as here.

   elfutils is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received copies of the GNU General Public License and
   the GNU Lesser General Public License along with this program.  If
   not, see <http://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <assert.h>
#include <stddef.h>
#include <stdlib.h>
#include <sys/mman.h>

#include "libelfP.h"


int
elf_end (Elf *elf)
{
  Elf *parent;

  if (elf == NULL)
    /* This is allowed and is a no-op.  */
    return 0;

  /* Make sure we are alone.  */
  rwlock_wrlock (elf->lock);

  if (elf->ref_count != 0 && --elf->ref_count != 0)
    {
      /* Not yet the last activation.  */
      int result = elf->ref_count;
      rwlock_unlock (elf->lock);
      return result;
    }

  if (elf->kind == ELF_K_AR)
    {
      /* We cannot remove the descriptor now since we still have some
	 descriptors which depend on it.  But we can free the archive
	 symbol table since this is only available via the archive ELF
	 descriptor.  The long name table cannot be freed yet since
	 the archive headers for the ELF files in the archive point
	 into this array.  */
      if (elf->state.ar.ar_sym != (Elf_Arsym *) -1l)
	free (elf->state.ar.ar_sym);
      elf->state.ar.ar_sym = NULL;

      if (elf->state.ar.children != NULL)
	return 0;
    }

  /* Remove this structure from the children list.  */
  parent = elf->parent;
  if (parent != NULL)
    {
      /* This is tricky.  Lock must be acquire from the father to
	 the child but here we already have the child lock.  We
	 solve this problem by giving free the child lock.  The
	 state of REF_COUNT==0 is handled all over the library, so
	 this should be ok.  */
      rwlock_unlock (elf->lock);
      rwlock_rdlock (parent->lock);
      rwlock_wrlock (elf->lock);

      if (parent->state.ar.children == elf)
	parent->state.ar.children = elf->next;
      else
	{
	  struct Elf *child = parent->state.ar.children;

	  while (child->next != elf)
	    child = child->next;

	  child->next = elf->next;
	}

      rwlock_unlock (parent->lock);
    }

  /* This was the last activation.  Free all resources.  */
  switch (elf->kind)
    {
    case ELF_K_AR:
      if (elf->state.ar.long_names != NULL)
	free (elf->state.ar.long_names);
      break;

    case ELF_K_ELF:
      {
	Elf_Data_Chunk *rawchunks
	  = (elf->class == ELFCLASS32
	     || (offsetof (struct Elf, state.elf32.rawchunks)
		 == offsetof (struct Elf, state.elf64.rawchunks))
	     ? elf->state.elf32.rawchunks
	     : elf->state.elf64.rawchunks);
	while (rawchunks != NULL)
	  {
	    Elf_Data_Chunk *next = rawchunks->next;
	    if (rawchunks->dummy_scn.flags & ELF_F_MALLOCED)
	      free (rawchunks->data.d.d_buf);
	    free (rawchunks);
	    rawchunks = next;
	  }

	Elf_ScnList *list = (elf->class == ELFCLASS32
			     || (offsetof (struct Elf, state.elf32.scns)
				 == offsetof (struct Elf, state.elf64.scns))
			     ? &elf->state.elf32.scns
			     : &elf->state.elf64.scns);

	do
	  {
	    /* Free all separately allocated section headers.  */
	    size_t cnt = list->max;

	    while (cnt-- > 0)
	      {
		/* These pointers can be NULL; it's safe to use
		   'free' since it will check for this.  */
		Elf_Scn *scn = &list->data[cnt];
		Elf_Data_List *runp;

		if ((scn->shdr_flags & ELF_F_MALLOCED) != 0)
		  /* It doesn't matter which pointer.  */
		  free (scn->shdr.e32);

		/* If the file has the same byte order and the
		   architecture doesn't require overly stringent
		   alignment the raw data buffer is the same as the
		   one used for presenting to the caller.  */
		if (scn->data_base != scn->rawdata_base)
		  free (scn->data_base);

		/* The section data is allocated if we couldn't mmap
		   the file.  */
		if (elf->map_address == NULL)
		  free (scn->rawdata_base);

		/* Free the list of data buffers for the section.
		   We don't free the buffers themselves since this
		   is the users job.  */
		runp = scn->data_list.next;
		while (runp != NULL)
		  {
		    Elf_Data_List *oldp = runp;
		    runp = runp->next;
		    if ((oldp->flags & ELF_F_MALLOCED) != 0)
		      free (oldp);
		  }
	      }

	    /* Free the memory for the array.  */
	    Elf_ScnList *oldp = list;
	    list = list->next;
	    assert (list == NULL || oldp->cnt == oldp->max);
	    if (oldp != (elf->class == ELFCLASS32
			 || (offsetof (struct Elf, state.elf32.scns)
			     == offsetof (struct Elf, state.elf64.scns))
			 ? &elf->state.elf32.scns
			 : &elf->state.elf64.scns))
	      free (oldp);
	  }
	while (list != NULL);
      }

      /* Free the section header.  */
      if (elf->state.elf.shdr_malloced  != 0)
	free (elf->class == ELFCLASS32
	      || (offsetof (struct Elf, state.elf32.shdr)
		  == offsetof (struct Elf, state.elf64.shdr))
	      ? (void *) elf->state.elf32.shdr
	      : (void *) elf->state.elf64.shdr);

      /* Free the program header.  */
      if ((elf->state.elf.phdr_flags & ELF_F_MALLOCED) != 0)
	free (elf->class == ELFCLASS32
	      || (offsetof (struct Elf, state.elf32.phdr)
		  == offsetof (struct Elf, state.elf64.phdr))
	      ? (void *) elf->state.elf32.phdr
	      : (void *) elf->state.elf64.phdr);
      break;

    default:
      break;
    }

  if (elf->map_address != NULL && parent == NULL)
    {
      /* The file was read or mapped for this descriptor.  */
      if ((elf->flags & ELF_F_MALLOCED) != 0)
	free (elf->map_address);
      else if ((elf->flags & ELF_F_MMAPPED) != 0)
	munmap (elf->map_address, elf->maximum_size);
    }

  rwlock_unlock (elf->lock);
  rwlock_fini (elf->lock);

  /* Finally the descriptor itself.  */
  free (elf);

  return (parent != NULL && parent->ref_count == 0
	  ? INTUSE(elf_end) (parent) : 0);
}
INTDEF(elf_end)