/* Print usage information and help for ld.so.

   Copyright (C) 1995-2020 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <https://www.gnu.org/licenses/>.  */

#include <dl-cache.h>

#include <dl-main.h>

#include <ldsodefs.h>

#include <unistd.h>

#include "version.h"

#include <dl-hwcaps.h>

void

_dl_usage (const char *argv0, const char *wrong_option)

{

  if (wrong_option != NULL)

    _dl_error_printf ("%s: unrecognized option '%s'\n", argv0, wrong_option);

  else

    _dl_error_printf ("%s: missing program name\n", argv0);

  _dl_error_printf ("Try '%s --help' for more information.\n", argv0);

  _exit (EXIT_FAILURE);

}

void

_dl_version (void)

{

  _dl_printf ("\

ld.so " PKGVERSION RELEASE " release version " VERSION ".\n\

Copyright (C) 2020 Free Software Foundation, Inc.\n\

This is free software; see the source for copying conditions.\n\

There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A\n\

PARTICULAR PURPOSE.\n\

");

  _exit (EXIT_SUCCESS);

}

/* Print part of the library search path (from a single source).  */

static void

print_search_path_for_help_1 (struct r_search_path_elem **list)

{

  if (list == NULL || list == (void *) -1)

    /* Path is missing or marked as inactive.  */

    return;

  for (; *list != NULL; ++list)

    {

      _dl_write (STDOUT_FILENO, "  ", 2);

      const char *name = (*list)->dirname;

      size_t namelen = (*list)->dirnamelen;

      if (namelen == 0)

        {

          /* The empty string denotes the current directory.  */

          name = ".";

          namelen = 1;

        }

      else if (namelen > 1)

        /* Remove the trailing slash.  */

        --namelen;

      _dl_write (STDOUT_FILENO, name, namelen);

      _dl_printf (" (%s)\n", (*list)->what);

    }

}

/* Prints the library search path.  See _dl_init_paths in dl-load.c

   how this information is populated.  */

static void

print_search_path_for_help (struct dl_main_state *state)

{

  if (__rtld_search_dirs.dirs == NULL)

    /* The run-time search paths have not yet been initialized.  */

    _dl_init_paths (state->library_path, state->library_path_source);

  _dl_printf ("\nShared library search path:\n");

  /* The print order should reflect the processing in

     _dl_map_object.  */

  struct link_map *map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;

  if (map != NULL)

    print_search_path_for_help_1 (map->l_rpath_dirs.dirs);

  print_search_path_for_help_1 (__rtld_env_path_list.dirs);

  if (map != NULL)

    print_search_path_for_help_1 (map->l_runpath_dirs.dirs);

  _dl_printf ("  (libraries located via %s)\n", LD_SO_CACHE);

  print_search_path_for_help_1 (__rtld_search_dirs.dirs);

}

/* Helper function for printing flags associated with a HWCAP name.  */

static void

print_hwcap_1 (bool *first, bool active, const char *label)

{

  if (active)

    {

      if (*first)

        {

          _dl_printf (" (");

          *first = false;

        }

      else

        _dl_printf (", ");

      _dl_printf ("%s", label);

    }

}

/* Called after a series of print_hwcap_1 calls to emit the line

   terminator.  */

static void

print_hwcap_1_finish (bool *first)

{

  if (*first)

    _dl_printf ("\n");

  else

    _dl_printf (")\n");

}

/* Write a list of hwcap subdirectories to standard output.  See

 _dl_important_hwcaps in dl-hwcaps.c.  */

static void

print_legacy_hwcap_directories (void)

{

  _dl_printf ("\n\

Legacy HWCAP subdirectories under library search path directories:\n");

  const char *platform = GLRO (dl_platform);

  if (platform != NULL)

    _dl_printf ("  %s (AT_PLATFORM; supported, searched)\n", platform);

  _dl_printf ("  tls (supported, searched)\n");

  uint64_t hwcap_mask = GET_HWCAP_MASK();

  uint64_t searched = GLRO (dl_hwcap) & hwcap_mask;

  for (int n = 63; n >= 0; --n)

    {

      uint64_t bit = 1ULL << n;

      if (HWCAP_IMPORTANT & bit)

        {

          _dl_printf ("  %s", _dl_hwcap_string (n));

          bool first = true;

          print_hwcap_1 (&first, GLRO (dl_hwcap) & bit, "supported");

          print_hwcap_1 (&first, !(hwcap_mask & bit), "masked");

          print_hwcap_1 (&first, searched & bit, "searched");

          print_hwcap_1_finish (&first);

        }

    }

}

void

_dl_help (const char *argv0, struct dl_main_state *state)

{

  _dl_printf ("\

Usage: %s [OPTION]... EXECUTABLE-FILE [ARGS-FOR-PROGRAM...]\n\

You have invoked 'ld.so', the program interpreter for dynamically-linked\n\

ELF programs.  Usually, the program interpreter is invoked automatically\n\

when a dynamically-linked executable is started.\n\

\n\

You may invoke the program interpreter program directly from the command\n\

line to load and run an ELF executable file; this is like executing that\n\

file itself, but always uses the program interpreter you invoked,\n\

instead of the program interpreter specified in the executable file you\n\

run.  Invoking the program interpreter directly provides access to\n\

additional diagnostics, and changing the dynamic linker behavior without\n\

setting environment variables (which would be inherited by subprocesses).\n\

\n\

  --list                list all dependencies and how they are resolved\n\

  --verify              verify that given object really is a dynamically linked\n\

                        object we can handle\n\

  --inhibit-cache       Do not use " LD_SO_CACHE "\n\

  --library-path PATH   use given PATH instead of content of the environment\n\

                        variable LD_LIBRARY_PATH\n\

  --inhibit-rpath LIST  ignore RUNPATH and RPATH information in object names\n\

                        in LIST\n\

  --audit LIST          use objects named in LIST as auditors\n\

  --preload LIST        preload objects named in LIST\n\

  --argv0 STRING        set argv[0] to STRING before running\n\

  --help                display this help and exit\n\

  --version             output version information and exit\n\

\n\

This program interpreter self-identifies as: " RTLD "\n\

",

              argv0);

  print_search_path_for_help (state);

  print_legacy_hwcap_directories ();

  _exit (EXIT_SUCCESS);

}