path: root/elf/dl-usage.c

/* Print usage information and help for ld.so.
   Copyright (C) 1995-2021 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-procinfo.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) 2021 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.  */
    call_init_paths (state);

  _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");
}

/* Print the header for print_hwcaps_subdirectories.  */
static void
print_hwcaps_subdirectories_header (bool *nothing_printed)
{
  if (*nothing_printed)
    {
      _dl_printf ("\n\
Subdirectories of glibc-hwcaps directories, in priority order:\n");
      *nothing_printed = false;
    }
}

/* Print the HWCAP name itself, indented.  */
static void
print_hwcaps_subdirectories_name (const struct dl_hwcaps_split *split)
{
  _dl_write (STDOUT_FILENO, "  ", 2);
  _dl_write (STDOUT_FILENO, split->segment, split->length);
}

/* Print the list of recognized glibc-hwcaps subdirectories.  */
static void
print_hwcaps_subdirectories (const struct dl_main_state *state)
{
  bool nothing_printed = true;
  struct dl_hwcaps_split split;

  /* The prepended glibc-hwcaps subdirectories.  */
  _dl_hwcaps_split_init (&split, state->glibc_hwcaps_prepend);
  while (_dl_hwcaps_split (&split))
    {
      print_hwcaps_subdirectories_header (&nothing_printed);
      print_hwcaps_subdirectories_name (&split);
      bool first = true;
      print_hwcap_1 (&first, true, "searched");
      print_hwcap_1_finish (&first);
    }

  /* The built-in glibc-hwcaps subdirectories.  Do the filtering
     manually, so that more precise diagnostics are possible.  */
  uint32_t mask = _dl_hwcaps_subdirs_active ();
  _dl_hwcaps_split_init (&split, _dl_hwcaps_subdirs);
  while (_dl_hwcaps_split (&split))
    {
      print_hwcaps_subdirectories_header (&nothing_printed);
      print_hwcaps_subdirectories_name (&split);
      bool first = true;
      print_hwcap_1 (&first, mask & 1, "supported");
      bool listed = _dl_hwcaps_contains (state->glibc_hwcaps_mask,
                                         split.segment, split.length);
      print_hwcap_1 (&first, !listed, "masked");
      print_hwcap_1 (&first, (mask & 1) && listed, "searched");
      print_hwcap_1_finish (&first);
      mask >>= 1;
    }

  if (nothing_printed)
    _dl_printf ("\n\
No subdirectories of glibc-hwcaps directories are searched.\n"