sysdeps/generic/dl-cache.h

   1 /* Support for reading /etc/ld.so.cache files written by Linux ldconfig.
   2    Copyright (C) 1999-2018 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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <stdint.h>
  20
  21 #ifndef _DL_CACHE_DEFAULT_ID
  22 # define _DL_CACHE_DEFAULT_ID   3
  23 #endif
  24
  25 #ifndef _dl_cache_check_flags
  26 # define _dl_cache_check_flags(flags)                   \
  27   ((flags) == 1 || (flags) == _DL_CACHE_DEFAULT_ID)
  28 #endif
  29
  30 #ifndef LD_SO_CACHE
  31 # define LD_SO_CACHE SYSCONFDIR "/ld.so.cache"
  32 #endif
  33
  34 #ifndef add_system_dir
  35 # define add_system_dir(dir) add_dir (dir)
  36 #endif
  37
  38 #define CACHEMAGIC "ld.so-1.7.0"
  39
  40 /* libc5 and glibc 2.0/2.1 use the same format.  For glibc 2.2 another
  41    format has been added in a compatible way:
  42    The beginning of the string table is used for the new table:
  43         old_magic
  44         nlibs
  45         libs[0]
  46         ...
  47         libs[nlibs-1]
  48         pad, new magic needs to be aligned
  49              - this is string[0] for the old format
  50         new magic - this is string[0] for the new format
  51         newnlibs
  52         ...
  53         newlibs[0]
  54         ...
  55         newlibs[newnlibs-1]
  56         string 1
  57         string 2
  58         ...
  59 */
  60 struct file_entry
  61 {
  62   int flags;            /* This is 1 for an ELF library.  */
  63   unsigned int key, value; /* String table indices.  */
  64 };
  65
  66 struct cache_file
  67 {
  68   char magic[sizeof CACHEMAGIC - 1];
  69   unsigned int nlibs;
  70   struct file_entry libs[0];
  71 };
  72
  73 #define CACHEMAGIC_NEW "glibc-ld.so.cache"
  74 #define CACHE_VERSION "1.1"
  75 #define CACHEMAGIC_VERSION_NEW CACHEMAGIC_NEW CACHE_VERSION
  76
  77
  78 struct file_entry_new
  79 {
  80   int32_t flags;                /* This is 1 for an ELF library.  */
  81   uint32_t key, value;          /* String table indices.  */
  82   uint32_t osversion;           /* Required OS version.  */
  83   uint64_t hwcap;               /* Hwcap entry.  */
  84 };
  85
  86 struct cache_file_new
  87 {
  88   char magic[sizeof CACHEMAGIC_NEW - 1];
  89   char version[sizeof CACHE_VERSION - 1];
  90   uint32_t nlibs;               /* Number of entries.  */
  91   uint32_t len_strings;         /* Size of string table. */
  92   uint32_t unused[5];           /* Leave space for future extensions
  93                                    and align to 8 byte boundary.  */
  94   struct file_entry_new libs[0]; /* Entries describing libraries.  */
  95   /* After this the string table of size len_strings is found.  */
  96 };
  97
  98 /* Used to align cache_file_new.  */
  99 #define ALIGN_CACHE(addr)                               \
 100 (((addr) + __alignof__ (struct cache_file_new) -1)      \
 101  & (~(__alignof__ (struct cache_file_new) - 1)))
 102
 103 extern int _dl_cache_libcmp (const char *p1, const char *p2) attribute_hidden;