elf/dl-usage.c

   1 /* Print usage information and help for ld.so.
   2    Copyright (C) 1995-2023 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) 2023 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   _dl_printf ("  (libraries located via %s)\n", LD_SO_CACHE);
 103
 104   print_search_path_for_help_1 (__rtld_search_dirs.dirs);
 105 }
 106
 107 /* Print the header for print_hwcaps_subdirectories.  */
 108 static void
 109 print_hwcaps_subdirectories_header (bool *nothing_printed)
 110 {
 111   if (*nothing_printed)
 112     {
 113       _dl_printf ("\n\
 114 Subdirectories of glibc-hwcaps directories, in priority order:\n");
 115       *nothing_printed = false;
 116     }
 117 }
 118
 119 /* Print the HWCAP name itself, indented.  */
 120 static void
 121 print_hwcaps_subdirectories_name (const struct dl_hwcaps_split *split)
 122 {
 123   _dl_write (STDOUT_FILENO, "  ", 2);
 124   _dl_write (STDOUT_FILENO, split->segment, split->length);
 125 }
 126
 127 /* Print the list of recognized glibc-hwcaps subdirectories.  */
 128 static void
 129 print_hwcaps_subdirectories (const struct dl_main_state *state)
 130 {
 131   bool nothing_printed = true;
 132   struct dl_hwcaps_split split;
 133
 134   /* The prepended glibc-hwcaps subdirectories.  */
 135   _dl_hwcaps_split_init (&split, state->glibc_hwcaps_prepend);
 136   while (_dl_hwcaps_split (&split))
 137     {
 138       print_hwcaps_subdirectories_header (&nothing_printed);
 139       print_hwcaps_subdirectories_name (&split);
 140       _dl_printf (" (searched)\n");
 141     }
 142
 143   /* The built-in glibc-hwcaps subdirectories.  Do the filtering
 144      manually, so that more precise diagnostics are possible.  */
 145   uint32_t mask = _dl_hwcaps_subdirs_active ();
 146   _dl_hwcaps_split_init (&split, _dl_hwcaps_subdirs);
 147   while (_dl_hwcaps_split (&split))
 148     {
 149       print_hwcaps_subdirectories_header (&nothing_printed);
 150       print_hwcaps_subdirectories_name (&split);
 151       bool listed = _dl_hwcaps_contains (state->glibc_hwcaps_mask,
 152                                          split.segment, split.length);
 153       if (mask & 1)
 154         _dl_printf (" (supported, %s)\n", listed ? "searched" : "masked");
 155       else if (!listed)
 156         _dl_printf (" (masked)\n");
 157       else
 158         _dl_printf ("\n");
 159       mask >>= 1;
 160     }
 161
 162   if (nothing_printed)
 163     _dl_printf ("\n\
 164 No subdirectories of glibc-hwcaps directories are searched.\n");
 165 }
 166
 167 void
 168 _dl_help (const char *argv0, struct dl_main_state *state)
 169 {
 170   _dl_printf ("\
 171 Usage: %s [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\
 172 You have invoked 'ld.so', the program interpreter for dynamically-linked\n\
 173 ELF programs.  Usually, the program interpreter is invoked automatically\n\
 174 when a dynamically-linked executable is started.\n\
 175 \n\
 176 You may invoke the program interpreter program directly from the command\n\
 177 line to load and run an ELF executable file; this is like executing that\n\
 178 file itself, but always uses the program interpreter you invoked,\n\
 179 instead of the program interpreter specified in the executable file you\n\
 180 run.  Invoking the program interpreter directly provides access to\n\
 181 additional diagnostics, and changing the dynamic linker behavior without\n\
 182 setting environment variables (which would be inherited by subprocesses).\n\
 183 \n\
 184   --list                list all dependencies and how they are resolved\n\
 185   --verify              verify that given object really is a dynamically linked\n\
 186                         object we can handle\n\
 187   --inhibit-cache       Do not use " LD_SO_CACHE "\n\
 188   --library-path PATH   use given PATH instead of content of the environment\n\
 189                         variable LD_LIBRARY_PATH\n\
 190   --glibc-hwcaps-prepend LIST\n\
 191                         search glibc-hwcaps subdirectories in LIST\n\
 192   --glibc-hwcaps-mask LIST\n\
 193                         only search built-in subdirectories if in LIST\n\
 194   --inhibit-rpath LIST  ignore RUNPATH and RPATH information in object names\n\
 195                         in LIST\n\
 196   --audit LIST          use objects named in LIST as auditors\n\
 197   --preload LIST        preload objects named in LIST\n\
 198   --argv0 STRING        set argv[0] to STRING before running\n\
 199   --list-tunables       list all tunables with minimum and maximum values\n\
 200   --list-diagnostics    list diagnostics information\n\
 201   --help                display this help and exit\n\
 202   --version             output version information and exit\n\
 203 \n\
 204 This program interpreter self-identifies as: " RTLD "\n\
 205 ",
 206               argv0);
 207   print_search_path_for_help (state);
 208   print_hwcaps_subdirectories (state);
 209   _exit (EXIT_SUCCESS);
 210 }