Home | History | Annotate | Download | only in libelf
      1 /* Free resources associated with Elf descriptor.
      2    Copyright (C) 1998,1999,2000,2001,2002,2004,2005,2007 Red Hat, Inc.
      3    This file is part of Red Hat elfutils.
      4    Written by Ulrich Drepper <drepper (at) redhat.com>, 1998.
      5 
      6    Red Hat elfutils is free software; you can redistribute it and/or modify
      7    it under the terms of the GNU General Public License as published by the
      8    Free Software Foundation; version 2 of the License.
      9 
     10    Red Hat elfutils is distributed in the hope that it will be useful, but
     11    WITHOUT ANY WARRANTY; without even the implied warranty of
     12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13    General Public License for more details.
     14 
     15    You should have received a copy of the GNU General Public License along
     16    with Red Hat elfutils; if not, write to the Free Software Foundation,
     17    Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
     18 
     19    In addition, as a special exception, Red Hat, Inc. gives You the
     20    additional right to link the code of Red Hat elfutils with code licensed
     21    under any Open Source Initiative certified open source license
     22    (http://www.opensource.org/licenses/index.php) which requires the
     23    distribution of source code with any binary distribution and to
     24    distribute linked combinations of the two.  Non-GPL Code permitted under
     25    this exception must only link to the code of Red Hat elfutils through
     26    those well defined interfaces identified in the file named EXCEPTION
     27    found in the source code files (the "Approved Interfaces").  The files
     28    of Non-GPL Code may instantiate templates or use macros or inline
     29    functions from the Approved Interfaces without causing the resulting
     30    work to be covered by the GNU General Public License.  Only Red Hat,
     31    Inc. may make changes or additions to the list of Approved Interfaces.
     32    Red Hat's grant of this exception is conditioned upon your not adding
     33    any new exceptions.  If you wish to add a new Approved Interface or
     34    exception, please contact Red Hat.  You must obey the GNU General Public
     35    License in all respects for all of the Red Hat elfutils code and other
     36    code used in conjunction with Red Hat elfutils except the Non-GPL Code
     37    covered by this exception.  If you modify this file, you may extend this
     38    exception to your version of the file, but you are not obligated to do
     39    so.  If you do not wish to provide this exception without modification,
     40    you must delete this exception statement from your version and license
     41    this file solely under the GPL without exception.
     42 
     43    Red Hat elfutils is an included package of the Open Invention Network.
     44    An included package of the Open Invention Network is a package for which
     45    Open Invention Network licensees cross-license their patents.  No patent
     46    license is granted, either expressly or impliedly, by designation as an
     47    included package.  Should you wish to participate in the Open Invention
     48    Network licensing program, please visit www.openinventionnetwork.com
     49    <http://www.openinventionnetwork.com>.  */
     50 
     51 #ifdef HAVE_CONFIG_H
     52 # include <config.h>
     53 #endif
     54 
     55 #include <assert.h>
     56 #include <stddef.h>
     57 #include <stdlib.h>
     58 #include <sys/mman.h>
     59 
     60 #include "libelfP.h"
     61 
     62 
     63 int
     64 elf_end (elf)
     65      Elf *elf;
     66 {
     67   Elf *parent;
     68 
     69   if (elf == NULL)
     70     /* This is allowed and is a no-op.  */
     71     return 0;
     72 
     73   /* Make sure we are alone.  */
     74   rwlock_wrlock (elf->lock);
     75 
     76   if (elf->ref_count != 0 && --elf->ref_count != 0)
     77     {
     78       /* Not yet the last activation.  */
     79       int result = elf->ref_count;
     80       rwlock_unlock (elf->lock);
     81       return result;
     82     }
     83 
     84   if (elf->kind == ELF_K_AR)
     85     {
     86       /* We cannot remove the descriptor now since we still have some
     87 	 descriptors which depend on it.  But we can free the archive
     88 	 symbol table since this is only available via the archive ELF
     89 	 descriptor.  The long name table cannot be freed yet since
     90 	 the archive headers for the ELF files in the archive point
     91 	 into this array.  */
     92       if (elf->state.ar.ar_sym != (Elf_Arsym *) -1l)
     93 	free (elf->state.ar.ar_sym);
     94       elf->state.ar.ar_sym = NULL;
     95 
     96       if (elf->state.ar.children != NULL)
     97 	return 0;
     98     }
     99 
    100   /* Remove this structure from the children list.  */
    101   parent = elf->parent;
    102   if (parent != NULL)
    103     {
    104       /* This is tricky.  Lock must be acquire from the father to
    105 	 the child but here we already have the child lock.  We
    106 	 solve this problem by giving free the child lock.  The
    107 	 state of REF_COUNT==0 is handled all over the library, so
    108 	 this should be ok.  */
    109       rwlock_unlock (elf->lock);
    110       rwlock_rdlock (parent->lock);
    111       rwlock_wrlock (elf->lock);
    112 
    113       if (parent->state.ar.children == elf)
    114 	parent->state.ar.children = elf->next;
    115       else
    116 	{
    117 	  struct Elf *child = parent->state.ar.children;
    118 
    119 	  while (child->next != elf)
    120 	    child = child->next;
    121 
    122 	  child->next = elf->next;
    123 	}
    124 
    125       rwlock_unlock (parent->lock);
    126     }
    127 
    128   /* This was the last activation.  Free all resources.  */
    129   switch (elf->kind)
    130     {
    131     case ELF_K_AR:
    132       if (elf->state.ar.long_names != NULL)
    133 	free (elf->state.ar.long_names);
    134       break;
    135 
    136     case ELF_K_ELF:
    137       {
    138 	Elf_Data_Chunk *rawchunks
    139 	  = (elf->class == ELFCLASS32
    140 	     || (offsetof (struct Elf, state.elf32.rawchunks)
    141 		 == offsetof (struct Elf, state.elf64.rawchunks))
    142 	     ? elf->state.elf32.rawchunks
    143 	     : elf->state.elf64.rawchunks);
    144 	while (rawchunks != NULL)
    145 	  {
    146 	    Elf_Data_Chunk *next = rawchunks->next;
    147 	    if (rawchunks->dummy_scn.flags & ELF_F_MALLOCED)
    148 	      free (rawchunks->data.d.d_buf);
    149 	    free (rawchunks);
    150 	    rawchunks = next;
    151 	  }
    152 
    153 	Elf_ScnList *list = (elf->class == ELFCLASS32
    154 			     || (offsetof (struct Elf, state.elf32.scns)
    155 				 == offsetof (struct Elf, state.elf64.scns))
    156 			     ? &elf->state.elf32.scns
    157 			     : &elf->state.elf64.scns);
    158 
    159 	do
    160 	  {
    161 	    /* Free all separately allocated section headers.  */
    162 	    size_t cnt = list->max;
    163 
    164 	    while (cnt-- > 0)
    165 	      {
    166 		/* These pointers can be NULL; it's safe to use
    167 		   'free' since it will check for this.  */
    168 		Elf_Scn *scn = &list->data[cnt];
    169 		Elf_Data_List *runp;
    170 
    171 		if ((scn->shdr_flags & ELF_F_MALLOCED) != 0)
    172 		  /* It doesn't matter which pointer.  */
    173 		  free (scn->shdr.e32);
    174 
    175 		/* If the file has the same byte order and the
    176 		   architecture doesn't require overly stringent
    177 		   alignment the raw data buffer is the same as the
    178 		   one used for presenting to the caller.  */
    179 		if (scn->data_base != scn->rawdata_base)
    180 		  free (scn->data_base);
    181 
    182 		/* The section data is allocated if we couldn't mmap
    183 		   the file.  */
    184 		if (elf->map_address == NULL)
    185 		  free (scn->rawdata_base);
    186 
    187 		/* Free the list of data buffers for the section.
    188 		   We don't free the buffers themselves since this
    189 		   is the users job.  */
    190 		runp = scn->data_list.next;
    191 		while (runp != NULL)
    192 		  {
    193 		    Elf_Data_List *oldp = runp;
    194 		    runp = runp->next;
    195 		    if ((oldp->flags & ELF_F_MALLOCED) != 0)
    196 		      free (oldp);
    197 		  }
    198 	      }
    199 
    200 	    /* Free the memory for the array.  */
    201 	    Elf_ScnList *oldp = list;
    202 	    list = list->next;
    203 	    assert (list == NULL || oldp->cnt == oldp->max);
    204 	    if (oldp != (elf->class == ELFCLASS32
    205 			 || (offsetof (struct Elf, state.elf32.scns)
    206 			     == offsetof (struct Elf, state.elf64.scns))
    207 			 ? &elf->state.elf32.scns
    208 			 : &elf->state.elf64.scns))
    209 	      free (oldp);
    210 	  }
    211 	while (list != NULL);
    212       }
    213 
    214       /* Free the section header.  */
    215       if (elf->state.elf.shdr_malloced  != 0)
    216 	free (elf->class == ELFCLASS32
    217 	      || (offsetof (struct Elf, state.elf32.shdr)
    218 		  == offsetof (struct Elf, state.elf64.shdr))
    219 	      ? (void *) elf->state.elf32.shdr
    220 	      : (void *) elf->state.elf64.shdr);
    221 
    222       /* Free the program header.  */
    223       if ((elf->state.elf.phdr_flags & ELF_F_MALLOCED) != 0)
    224 	free (elf->class == ELFCLASS32
    225 	      || (offsetof (struct Elf, state.elf32.phdr)
    226 		  == offsetof (struct Elf, state.elf64.phdr))
    227 	      ? (void *) elf->state.elf32.phdr
    228 	      : (void *) elf->state.elf64.phdr);
    229       break;
    230 
    231     default:
    232       break;
    233     }
    234 
    235   if (elf->map_address != NULL && parent == NULL)
    236     {
    237       /* The file was read or mapped for this descriptor.  */
    238       if ((elf->flags & ELF_F_MALLOCED) != 0)
    239 	free (elf->map_address);
    240       else if ((elf->flags & ELF_F_MMAPPED) != 0)
    241 	munmap (elf->map_address, elf->maximum_size);
    242     }
    243 
    244   rwlock_fini (elf->lock);
    245 
    246   /* Finally the descriptor itself.  */
    247   free (elf);
    248 
    249   return (parent != NULL && parent->ref_count == 0
    250 	  ? INTUSE(elf_end) (parent) : 0);
    251 }
    252 INTDEF(elf_end)
    253