elf/dl-main.h

   1 /* Information collection during ld.so startup.
   2    Copyright (C) 1995-2021 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _DL_MAIN
  20 #define _DL_MAIN
  21
  22 #include <ldsodefs.h>
  23 #include <limits.h>
  24 #include <stdlib.h>
  25
  26 /* Length limits for names and paths, to protect the dynamic linker,
  27    particularly when __libc_enable_secure is active.  */
  28 #ifdef NAME_MAX
  29 # define SECURE_NAME_LIMIT NAME_MAX
  30 #else
  31 # define SECURE_NAME_LIMIT 255
  32 #endif
  33 #ifdef PATH_MAX
  34 # define SECURE_PATH_LIMIT PATH_MAX
  35 #else
  36 # define SECURE_PATH_LIMIT 1024
  37 #endif
  38
  39 /* Strings containing colon-separated lists of audit modules.  */
  40 struct audit_list
  41 {
  42   /* Array of strings containing colon-separated path lists.  Each
  43      audit module needs its own namespace, so pre-allocate the largest
  44      possible list.  */
  45   const char *audit_strings[DL_NNS];
  46
  47   /* Number of entries added to audit_strings.  */
  48   size_t length;
  49
  50   /* Index into the audit_strings array (for the iteration phase).  */
  51   size_t current_index;
  52
  53   /* Tail of audit_strings[current_index] which still needs
  54      processing.  */
  55   const char *current_tail;
  56
  57   /* Scratch buffer for returning a name which is part of the strings
  58      in audit_strings.  */
  59   char fname[SECURE_NAME_LIMIT];
  60 };
  61
  62 /* This is a list of all the modes the dynamic loader can be in.  */
  63 enum rtld_mode
  64   {
  65     rtld_mode_normal, rtld_mode_list, rtld_mode_verify, rtld_mode_trace,
  66     rtld_mode_list_tunables, rtld_mode_list_diagnostics, rtld_mode_help,
  67   };
  68
  69 /* Aggregated state information extracted from environment variables
  70    and the ld.so command line.  */
  71 struct dl_main_state
  72 {
  73   struct audit_list audit_list;
  74
  75   /* The library search path.  */
  76   const char *library_path;
  77
  78   /* Where library_path comes from.  LD_LIBRARY_PATH or --library-path.  */
  79   const char *library_path_source;
  80
  81   /* The list preloaded objects from LD_PRELOAD.  */
  82   const char *preloadlist;
  83
  84   /* The preload list passed as a command argument.  */
  85   const char *preloadarg;
  86
  87   /* Additional glibc-hwcaps subdirectories to search first.
  88      Colon-separated list.  */
  89   const char *glibc_hwcaps_prepend;
  90
  91   /* Mask for the internal glibc-hwcaps subdirectories.
  92      Colon-separated list.  */
  93   const char *glibc_hwcaps_mask;
  94
  95   enum rtld_mode mode;
  96
  97   /* True if any of the debugging options is enabled.  */
  98   bool any_debug;
  99
 100   /* True if information about versions has to be printed.  */
 101   bool version_info;
 102 };
 103
 104 /* Helper function to invoke _dl_init_paths with the right arguments
 105    from *STATE.  */
 106 static inline void
 107 call_init_paths (const struct dl_main_state *state)
 108 {
 109   _dl_init_paths (state->library_path, state->library_path_source,
 110                   state->glibc_hwcaps_prepend, state->glibc_hwcaps_mask);
 111 }
 112
 113 /* Print ld.so usage information and exit.  */
 114 _Noreturn void _dl_usage (const char *argv0, const char *wrong_option)
 115   attribute_hidden;
 116
 117 /* Print ld.so version information and exit.  */
 118 _Noreturn void _dl_version (void) attribute_hidden;
 119
 120 /* Print ld.so --help output and exit.  */
 121 _Noreturn void _dl_help (const char *argv0, struct dl_main_state *state)
 122   attribute_hidden;
 123
 124 /* Print a diagnostics dump.  */
 125 _Noreturn void _dl_print_diagnostics (char **environ) attribute_hidden;
 126
 127 #endif /* _DL_MAIN */