1/* Free resources associated with Elf descriptor.
2   Copyright (C) 1998,1999,2000,2001,2002,2004,2005,2007,2015 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
42int
43elf_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		  free (scn->rawdata_base);
171
172		/* Free the list of data buffers for the section.
173		   We don't free the buffers themselves since this
174		   is the users job.  */
175		runp = scn->data_list.next;
176		while (runp != NULL)
177		  {
178		    Elf_Data_List *oldp = runp;
179		    runp = runp->next;
180		    if ((oldp->flags & ELF_F_MALLOCED) != 0)
181		      free (oldp);
182		  }
183	      }
184
185	    /* Free the memory for the array.  */
186	    Elf_ScnList *oldp = list;
187	    list = list->next;
188	    assert (list == NULL || oldp->cnt == oldp->max);
189	    if (oldp != (elf->class == ELFCLASS32
190			 || (offsetof (struct Elf, state.elf32.scns)
191			     == offsetof (struct Elf, state.elf64.scns))
192			 ? &elf->state.elf32.scns
193			 : &elf->state.elf64.scns))
194	      free (oldp);
195	  }
196	while (list != NULL);
197      }
198
199      /* Free the section header.  */
200      if (elf->state.elf.shdr_malloced  != 0)
201	free (elf->class == ELFCLASS32
202	      || (offsetof (struct Elf, state.elf32.shdr)
203		  == offsetof (struct Elf, state.elf64.shdr))
204	      ? (void *) elf->state.elf32.shdr
205	      : (void *) elf->state.elf64.shdr);
206
207      /* Free the program header.  */
208      if ((elf->state.elf.phdr_flags & ELF_F_MALLOCED) != 0)
209	free (elf->class == ELFCLASS32
210	      || (offsetof (struct Elf, state.elf32.phdr)
211		  == offsetof (struct Elf, state.elf64.phdr))
212	      ? (void *) elf->state.elf32.phdr
213	      : (void *) elf->state.elf64.phdr);
214      break;
215
216    default:
217      break;
218    }
219
220  if (elf->map_address != NULL && parent == NULL)
221    {
222      /* The file was read or mapped for this descriptor.  */
223      if ((elf->flags & ELF_F_MALLOCED) != 0)
224	free (elf->map_address);
225      else if ((elf->flags & ELF_F_MMAPPED) != 0)
226	munmap (elf->map_address, elf->maximum_size);
227    }
228
229  rwlock_unlock (elf->lock);
230  rwlock_fini (elf->lock);
231
232  /* Finally the descriptor itself.  */
233  free (elf);
234
235  return (parent != NULL && parent->ref_count == 0
236	  ? INTUSE(elf_end) (parent) : 0);
237}
238INTDEF(elf_end)
239