elf/dl-usage.c

   1 /* Print usage information and help for ld.so.
   2    Copyright (C) 1995-2024 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 #include <dl-cache.h>
  20 #include <dl-main.h>
  21 #include <ldsodefs.h>
  22 #include <unistd.h>
  23 #include "version.h"
  24
  25 #include <dl-procinfo.h>
  26 #include <dl-hwcaps.h>
  27
  28 void
  29 _dl_usage (const char *argv0, const char *wrong_option)
  30 {
  31   if (wrong_option != NULL)
  32     _dl_error_printf ("%s: unrecognized option '%s'\n", argv0, wrong_option);
  33   else
  34     _dl_error_printf ("%s: missing program name\n", argv0);
  35   _dl_error_printf ("Try '%s --help' for more information.\n", argv0);
  36   _exit (EXIT_FAILURE);
  37 }
  38
  39 void
  40 _dl_version (void)
  41 {
  42   _dl_printf ("\
  43 ld.so " PKGVERSION RELEASE " release version " VERSION ".\n\
  44 Copyright (C) 2024 Free Software Foundation, Inc.\n\
  45 This is free software; see the source for copying conditions.\n\
  46 There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A\n\
  47 PARTICULAR PURPOSE.\n\
  48 ");
  49   _exit (EXIT_SUCCESS);
  50 }
  51
  52 /* Print part of the library search path (from a single source).  */
  53 static void
  54 print_search_path_for_help_1 (struct r_search_path_elem **list)
  55 {
  56   if (list == NULL || list == (void *) -1)
  57     /* Path is missing or marked as inactive.  */
  58     return;
  59
  60   for (; *list != NULL; ++list)
  61     {
  62       _dl_write (STDOUT_FILENO, "  ", 2);
  63       const char *name = (*list)->dirname;
  64       size_t namelen = (*list)->dirnamelen;
  65       if (namelen == 0)
  66         {
  67           /* The empty string denotes the current directory.  */
  68           name = ".";
  69           namelen = 1;
  70         }
  71       else if (namelen > 1)
  72         /* Remove the trailing slash.  */
  73         --namelen;
  74       _dl_write (STDOUT_FILENO, name, namelen);
  75       _dl_printf (" (%s)\n", (*list)->what);
  76     }
  77 }
  78
  79 /* Prints the library search path.  See _dl_init_paths in dl-load.c
  80    how this information is populated.  */
  81 static void
  82 print_search_path_for_help (struct dl_main_state *state)
  83 {
  84   if (__rtld_search_dirs.dirs == NULL)
  85     /* The run-time search paths have not yet been initialized.  */
  86     call_init_paths (state);
  87
  88   _dl_printf ("\nShared library search path:\n");
  89
  90   /* The print order should reflect the processing in
  91      _dl_map_object.  */
  92
  93   struct link_map *map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
  94   if (map != NULL)
  95     print_search_path_for_help_1 (map->l_rpath_dirs.dirs);
  96
  97   print_search_path_for_help_1 (__rtld_env_path_list.dirs);
  98
  99   if (map != NULL)
 100     print_search_path_for_help_1 (map->l_runpath_dirs.dirs);
 101
 102   if (!GLRO(dl_inhibit_cache))
 103     _dl_printf ("  (libraries located via %s)\n", LD_SO_CACHE);
 104
 105   print_search_path_for_help_1 (__rtld_search_dirs.dirs);
 106 }
 107
 108 /* Print the header for print_hwcaps_subdirectories.  */
 109 static void
 110 print_hwcaps_subdirectories_header (bool *nothing_printed)
 111 {
 112   if (*nothing_printed)
 113     {
 114       _dl_printf ("\n\
 115 Subdirectories of glibc-hwcaps directories, in priority order:\n");
 116       *nothing_printed = false;
 117     }
 118 }
 119
 120 /* Print the HWCAP name itself, indented.  */
 121 static void
 122 print_hwcaps_subdirectories_name (const struct dl_hwcaps_split *split)
 123 {
 124   _dl_write (STDOUT_FILENO, "  ", 2);
 125   _dl_write (STDOUT_FILENO, split->segment, split->length);
 126 }
 127
 128 /* Print the list of recognized glibc-hwcaps subdirectories.  */
 129 static void
 130 print_hwcaps_subdirectories (const struct dl_main_state *state)
 131 {
 132   bool nothing_printed = true;
 133   struct dl_hwcaps_split split;
 134
 135   /* The prepended glibc-hwcaps subdirectories.  */
 136   _dl_hwcaps_split_init (&split, state->glibc_hwcaps_prepend);
 137   while (_dl_hwcaps_split (&split))
 138     {
 139       print_hwcaps_subdirectories_header (&nothing_printed);
 140       print_hwcaps_subdirectories_name (&split);
 141       _dl_printf (" (searched)\n");
 142     }
 143
 144   /* The built-in glibc-hwcaps subdirectories.  Do the filtering
 145      manually, so that more precise diagnostics are possible.  */
 146   uint32_t mask = _dl_hwcaps_subdirs_active ();
 147   _dl_hwcaps_split_init (&split, _dl_hwcaps_subdirs);
 148   while (_dl_hwcaps_split (&split))
 149     {
 150       print_hwcaps_subdirectories_header (&nothing_printed);
 151       print_hwcaps_subdirectories_name (&split);
 152       bool listed = _dl_hwcaps_contains (state->glibc_hwcaps_mask,
 153                                          split.segment, split.length);
 154       if (mask & 1)
 155         _dl_printf (" (supported, %s)\n", listed ? "searched" : "masked");
 156       else if (!listed)
 157         _dl_printf (" (masked)\n");
 158       else
 159         _dl_printf ("\n");
 160       mask >>= 1;
 161     }
 162
 163   if (nothing_printed)
 164     _dl_printf ("\n\
 165 No subdirectories of glibc-hwcaps directories are searched.\n");
 166 }
 167
 168 void
 169 _dl_help (const char *argv0, struct dl_main_state *state)
 170 {
 171   _dl_printf ("\
 172 Usage: %s [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
 173 You have invoked 'ld.so', the program interpreter for dynamically-linked\n\
 174 ELF programs.  Usually, the program interpreter is invoked automatically\n\
 175 when a dynamically-linked executable is started.\n\
 176 \n\
 177 You may invoke the program interpreter program directly from the command\n\
 178 line to load and run an ELF executable file; this is like executing that\n\
 179 file itself, but always uses the program interpreter you invoked,\n\
 180 instead of the program interpreter specified in the executable file you\n\
 181 run.  Invoking the program interpreter directly provides access to\n\
 182 additional diagnostics, and changing the dynamic linker behavior without\n\
 183 setting environment variables (which would be inherited by subprocesses).\n\
 184 \n\
 185   --list                list all dependencies and how they are resolved\n\
 186   --verify              verify that given object really is a dynamically linked\n\
 187                         object we can handle\n\
 188   --inhibit-cache       Do not use " LD_SO_CACHE "\n\
 189   --library-path PATH   use given PATH instead of content of the environment\n\
 190                         variable LD_LIBRARY_PATH\n\
 191   --glibc-hwcaps-prepend LIST\n\
 192                         search glibc-hwcaps subdirectories in LIST\n\
 193   --glibc-hwcaps-mask LIST\n\
 194                         only search built-in subdirectories if in LIST\n\
 195   --inhibit-rpath LIST  ignore RUNPATH and RPATH information in object names\n\
 196                         in LIST\n\
 197   --audit LIST          use objects named in LIST as auditors\n\
 198   --preload LIST        preload objects named in LIST\n\
 199   --argv0 STRING        set argv[0] to STRING before running\n\
 200   --list-tunables       list all tunables with minimum and maximum values\n\
 201   --list-diagnostics    list diagnostics information\n\
 202   --help                display this help and exit\n\
 203   --version             output version information and exit\n\
 204 \n\
 205 This program interpreter self-identifies as: " RTLD "\n\
 206 ",
 207               argv0);
 208   print_search_path_for_help (state);
 209   print_hwcaps_subdirectories (state);
 210   _exit (EXIT_SUCCESS);
 211 }