LCOV - code coverage report
Current view: top level - elfutils/libelf - elf_update.c (source / functions) Hit Total Coverage
Test: lcov.out Lines: 45 65 69.2 %
Date: 2013-03-08 Functions: 2 2 100.0 %
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: 47 72 65.3 %

           Branch data     Line data    Source code
       1                 :            : /* Update data structures for changes and write them out.
       2                 :            :    Copyright (C) 1999, 2000, 2001, 2002, 2004, 2005, 2006 Red Hat, Inc.
       3                 :            :    This file is part of elfutils.
       4                 :            :    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
       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 <libelf.h>
      35                 :            : #include <unistd.h>
      36                 :            : #include <sys/mman.h>
      37                 :            : #include <sys/stat.h>
      38                 :            : 
      39                 :            : #include "libelfP.h"
      40                 :            : 
      41                 :            : 
      42                 :            : static off_t
      43                 :         66 : write_file (Elf *elf, off_t size, int change_bo, size_t shnum)
      44                 :            : {
      45                 :         66 :   int class = elf->class;
      46                 :            : 
      47                 :            :   /* Check the mode bits now, before modification might change them.  */
      48                 :            :   struct stat st;
      49         [ -  + ]:         66 :   if (unlikely (fstat (elf->fildes, &st) != 0))
      50                 :            :     {
      51                 :          0 :       __libelf_seterrno (ELF_E_WRITE_ERROR);
      52                 :            :       return -1;
      53                 :            :     }
      54                 :            : 
      55                 :            :   /* Adjust the size in any case.  We do this even if we use `write'.
      56                 :            :      We cannot do this if this file is in an archive.  We also don't
      57                 :            :      do it *now* if we are shortening the file since this would
      58                 :            :      prevent programs to use the data of the file in generating the
      59                 :            :      new file.  We truncate the file later in this case.  */
      60         [ +  - ]:         66 :   if (elf->parent == NULL
      61         [ +  + ]:         66 :       && (elf->maximum_size == ~((size_t) 0)
      62         [ +  - ]:         64 :           || (size_t) size > elf->maximum_size)
      63         [ -  + ]:         66 :       && unlikely (ftruncate (elf->fildes, size) != 0))
      64                 :            :     {
      65                 :          0 :       __libelf_seterrno (ELF_E_WRITE_ERROR);
      66                 :            :       return -1;
      67                 :            :     }
      68                 :            : 
      69                 :            :   /* Try to map the file if this isn't done yet.  */
      70 [ +  + ][ +  + ]:         66 :   if (elf->map_address == NULL && elf->cmd == ELF_C_WRITE_MMAP)
      71                 :            :     {
      72                 :            : #if _MUDFLAP
      73                 :            :       /* Mudflap doesn't grok that our mmap'd data is ok.  */
      74                 :            : #else
      75                 :         48 :       elf->map_address = mmap (NULL, size, PROT_READ | PROT_WRITE,
      76                 :            :                                MAP_SHARED, elf->fildes, 0);
      77         [ -  + ]:         48 :       if (unlikely (elf->map_address == MAP_FAILED))
      78                 :          0 :         elf->map_address = NULL;
      79                 :            : #endif
      80                 :            :     }
      81                 :            : 
      82         [ +  + ]:         66 :   if (elf->map_address != NULL)
      83                 :            :     {
      84                 :            :       /* The file is mmaped.  */
      85         [ -  + ]:         50 :       if ((class == ELFCLASS32
      86                 :         22 :            ? __elf32_updatemmap (elf, change_bo, shnum)
      87         [ +  + ]:         72 :            : __elf64_updatemmap (elf, change_bo, shnum)) != 0)
      88                 :            :         /* Some problem while writing.  */
      89                 :          0 :         size = -1;
      90                 :            :     }
      91                 :            :   else
      92                 :            :     {
      93                 :            :       /* The file is not mmaped.  */
      94         [ -  + ]:         16 :       if ((class == ELFCLASS32
      95                 :         11 :            ? __elf32_updatefile (elf, change_bo, shnum)
      96         [ +  + ]:         27 :            : __elf64_updatefile (elf, change_bo, shnum)) != 0)
      97                 :            :         /* Some problem while writing.  */
      98                 :          0 :         size = -1;
      99                 :            :     }
     100                 :            : 
     101         [ +  - ]:         66 :   if (size != -1
     102         [ +  - ]:         66 :       && elf->parent == NULL
     103         [ +  + ]:         66 :       && elf->maximum_size != ~((size_t) 0)
     104         [ -  + ]:         64 :       && (size_t) size < elf->maximum_size
     105         [ #  # ]:          0 :       && unlikely (ftruncate (elf->fildes, size) != 0))
     106                 :            :     {
     107                 :          0 :       __libelf_seterrno (ELF_E_WRITE_ERROR);
     108                 :          0 :       size = -1;
     109                 :            :     }
     110                 :            : 
     111                 :            :   /* POSIX says that ftruncate and write may clear the S_ISUID and S_ISGID
     112                 :            :      mode bits.  So make sure we restore them afterwards if they were set.
     113                 :            :      This is not atomic if someone else chmod's the file while we operate.  */
     114         [ +  - ]:         66 :   if (size != -1
     115         [ -  + ]:         66 :       && unlikely (st.st_mode & (S_ISUID | S_ISGID))
     116                 :            :       /* fchmod ignores the bits we cannot change.  */
     117         [ #  # ]:          0 :       && unlikely (fchmod (elf->fildes, st.st_mode) != 0))
     118                 :            :     {
     119                 :          0 :       __libelf_seterrno (ELF_E_WRITE_ERROR);
     120                 :          0 :       size = -1;
     121                 :            :     }
     122                 :            : 
     123 [ +  - ][ +  - ]:         66 :   if (size != -1 && elf->parent == NULL)
     124                 :         66 :     elf->maximum_size = size;
     125                 :            : 
     126                 :            :   return size;
     127                 :            : }
     128                 :            : 
     129                 :            : 
     130                 :            : off_t
     131                 :         70 : elf_update (elf, cmd)
     132                 :            :      Elf *elf;
     133                 :            :      Elf_Cmd cmd;
     134                 :            : {
     135                 :            :   size_t shnum;
     136                 :            :   off_t size;
     137                 :         70 :   int change_bo = 0;
     138                 :            : 
     139         [ +  + ]:         70 :   if (cmd != ELF_C_NULL
     140                 :         70 :       && cmd != ELF_C_WRITE
     141         [ -  + ]:          9 :       && unlikely (cmd != ELF_C_WRITE_MMAP))
     142                 :            :     {
     143                 :          0 :       __libelf_seterrno (ELF_E_INVALID_CMD);
     144                 :            :       return -1;
     145                 :            :     }
     146                 :            : 
     147         [ +  - ]:         70 :   if (elf == NULL)
     148                 :            :     return -1;
     149                 :            : 
     150         [ -  + ]:         70 :   if (elf->kind != ELF_K_ELF)
     151                 :            :     {
     152                 :          0 :       __libelf_seterrno (ELF_E_INVALID_HANDLE);
     153                 :            :       return -1;
     154                 :            :     }
     155                 :            : 
     156                 :            :   rwlock_wrlock (elf->lock);
     157                 :            : 
     158                 :            :   /* Make sure we have an ELF header.  */
     159         [ -  + ]:         70 :   if (elf->state.elf.ehdr == NULL)
     160                 :            :     {
     161                 :          0 :       __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR);
     162                 :          0 :       size = -1;
     163                 :          0 :       goto out;
     164                 :            :     }
     165                 :            : 
     166                 :            :   /* Determine the number of sections.  */
     167                 :        140 :   shnum = (elf->state.elf.scns_last->cnt == 0
     168                 :            :            ? 0
     169         [ +  + ]:         70 :            : 1 + elf->state.elf.scns_last->data[elf->state.elf.scns_last->cnt - 1].index);
     170                 :            : 
     171                 :            :   /* Update the ELF descriptor.  First, place the program header.  It
     172                 :            :      will come right after the ELF header.  The count the size of all
     173                 :            :      sections and finally place the section table.  */
     174                 :        140 :   size = (elf->class == ELFCLASS32
     175                 :            :           ? __elf32_updatenull_wrlock (elf, &change_bo, shnum)
     176         [ +  + ]:         70 :           : __elf64_updatenull_wrlock (elf, &change_bo, shnum));
     177         [ +  - ]:         70 :   if (likely (size != -1)
     178                 :            :       /* See whether we actually have to write out the data.  */
     179         [ +  + ]:         70 :       && (cmd == ELF_C_WRITE || cmd == ELF_C_WRITE_MMAP))
     180                 :            :     {
     181         [ +  + ]:         66 :       if (elf->cmd != ELF_C_RDWR
     182                 :         66 :           && elf->cmd != ELF_C_RDWR_MMAP
     183         [ +  + ]:         62 :           && elf->cmd != ELF_C_WRITE
     184         [ -  + ]:         48 :           && unlikely (elf->cmd != ELF_C_WRITE_MMAP))
     185                 :            :         {
     186                 :          0 :           __libelf_seterrno (ELF_E_UPDATE_RO);
     187                 :          0 :           size = -1;
     188                 :            :         }
     189         [ -  + ]:         66 :       else if (unlikely (elf->fildes == -1))
     190                 :            :         {
     191                 :            :           /* We closed the file already.  */
     192                 :          0 :           __libelf_seterrno (ELF_E_FD_DISABLED);
     193                 :          0 :           size = -1;
     194                 :            :         }
     195                 :            :       else
     196                 :         70 :         size = write_file (elf, size, change_bo, shnum);
     197                 :            :     }
     198                 :            : 
     199                 :            :  out:
     200                 :            :   rwlock_unlock (elf->lock);
     201                 :            : 
     202                 :            :   return size;
     203                 :            : }

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