sysdeps/generic/dl-cache.h

   1 /* Support for reading /etc/ld.so.cache files written by Linux ldconfig.
   2    Copyright (C) 1999, 2000, 2002 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <stdint.h>
  21
  22 #ifndef _DL_CACHE_DEFAULT_ID
  23 # define _DL_CACHE_DEFAULT_ID   3
  24 #endif
  25
  26 #ifndef _dl_cache_check_flags
  27 # define _dl_cache_check_flags(flags)                   \
  28   ((flags) == 1 || (flags) == _DL_CACHE_DEFAULT_ID)
  29 #endif
  30
  31 #ifndef LD_SO_CACHE
  32 # define LD_SO_CACHE SYSCONFDIR "/ld.so.cache"
  33 #endif
  34
  35 #define CACHEMAGIC "ld.so-1.7.0"
  36
  37 /* libc5 and glibc 2.0/2.1 use the same format.  For glibc 2.2 another
  38    format has been added in a compatible way:
  39    The beginning of the string table is used for the new table:
  40         old_magic
  41         nlibs
  42         libs[0]
  43         ...
  44         libs[nlibs-1]
  45         pad, new magic needs to be aligned
  46              - this is string[0] for the old format
  47         new magic - this is string[0] for the new format
  48         newnlibs
  49         ...
  50         newlibs[0]
  51         ...
  52         newlibs[newnlibs-1]
  53         string 1
  54         string 2
  55         ...
  56 */
  57 struct file_entry
  58 {
  59   int flags;            /* This is 1 for an ELF library.  */
  60   unsigned int key, value; /* String table indices.  */
  61 };
  62
  63 struct cache_file
  64 {
  65   char magic[sizeof CACHEMAGIC - 1];
  66   unsigned int nlibs;
  67   struct file_entry libs[0];
  68 };
  69
  70 #define CACHEMAGIC_NEW "glibc-ld.so.cache"
  71 #define CACHE_VERSION "1.1"
  72 #define CACHEMAGIC_VERSION_NEW CACHEMAGIC_NEW CACHE_VERSION
  73
  74
  75 struct file_entry_new
  76 {
  77   int32_t flags;                /* This is 1 for an ELF library.  */
  78   uint32_t key, value;          /* String table indices.  */
  79   uint32_t osversion;           /* Required OS version.  */
  80   uint64_t hwcap;               /* Hwcap entry.  */
  81 };
  82
  83 struct cache_file_new
  84 {
  85   char magic[sizeof CACHEMAGIC_NEW - 1];
  86   char version[sizeof CACHE_VERSION - 1];
  87   uint32_t nlibs;               /* Number of entries.  */
  88   uint32_t len_strings;         /* Size of string table. */
  89   uint32_t unused[5];           /* Leave space for future extensions
  90                                    and align to 8 byte boundary.  */
  91   struct file_entry_new libs[0]; /* Entries describing libraries.  */
  92   /* After this the string table of size len_strings is found.  */
  93 };
  94
  95 /* Used to align cache_file_new.  */
  96 #define ALIGN_CACHE(addr)                               \
  97 (((addr) + __alignof__ (struct cache_file_new) -1)      \
  98  & (~(__alignof__ (struct cache_file_new) - 1)))
  99
 100 static int
 101 __attribute__ ((__unused__))
 102 _dl_cache_libcmp (const char *p1, const char *p2)
 103 {
 104   while (*p1 != '\0')
 105     {
 106       if (*p1 >= '0' && *p1 <= '9')
 107         {
 108           if (*p2 >= '0' && *p2 <= '9')
 109             {
 110               /* Must compare this numerically.  */
 111               int val1;
 112               int val2;
 113
 114               val1 = *p1++ - '0';
 115               val2 = *p2++ - '0';
 116               while (*p1 >= '0' && *p1 <= '9')
 117                 val1 = val1 * 10 + *p1++ - '0';
 118               while (*p2 >= '0' && *p2 <= '9')
 119                 val2 = val2 * 10 + *p2++ - '0';
 120               if (val1 != val2)
 121                 return val1 - val2;
 122             }
 123           else
 124             return 1;
 125         }
 126       else if (*p2 >= '0' && *p2 <= '9')
 127         return -1;
 128       else if (*p1 != *p2)
 129         return *p1 - *p2;
 130       else
 131         {
 132           ++p1;
 133           ++p2;
 134         }
 135     }
 136   return *p1 - *p2;
 137 }