path: root/elf/ldconfig.c

/* Copyright (C) 1999, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Andreas Jaeger <aj@suse.de>, 1999.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <alloca.h>
#include <argp.h>
#include <dirent.h>
#include <elf.h>
#include <error.h>
#include <errno.h>
#include <libintl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>

#include "ldconfig.h"
#include "dl-cache.h"

/* We don't need this here - silence the compiler.  */
#define _dl_sysdep_message(string, args...) do {} while (0);

#include "dl-procinfo.h"

#ifndef LD_SO_CONF
# define LD_SO_CONF SYSCONFDIR "/ld.so.conf"
#endif

/* Get libc version number.  */
#include <version.h>

#define PACKAGE _libc_intl_domainname

struct lib_entry
  {
    int flags;
    unsigned long int hwcap;
    char *lib;
    char *path;
  };

static const struct
{
  const char *name;
  int flag;
} lib_types [] =
{
  {"libc4", FLAG_LIBC4},
  {"libc5", FLAG_ELF_LIBC5},
  {"libc6", FLAG_ELF_LIBC6},
  {"glibc2", FLAG_ELF_LIBC6}
};


/* List of directories to handle.  */
struct dir_entry
{
  char *path;
  int flag;
  struct dir_entry *next;
};

/* The list is unsorted, contains no duplicates.  Entries are added at
   the end.  */
static struct dir_entry *dir_entries;

/* Flags for different options.  */
/* Print Cache.  */
static int opt_print_cache = 0;

/* Be verbose.  */
int opt_verbose = 0;

/* Format to support.  */
/* 0: only libc5/glibc2; 1: both; 2: only glibc 2.2.  */
int opt_format = 1;

/* Build cache.  */
static int opt_build_cache = 1;

/* Generate links.  */
static int opt_link = 1;

/* Only process directories specified on the command line.  */
static int opt_only_cline = 0;

/* Path to root for chroot.  */
static char *opt_chroot;

/* Manually link given shared libraries.  */
static int opt_manual_link = 0;

/* Cache file to use.  */
static char *cache_file;

/* Configuration file.  */
static const char *config_file;

/* Name and version of program.  */
static void print_version (FILE *stream, struct argp_state *state);
void (*argp_program_version_hook) (FILE *, struct argp_state *)
     = print_version;

/* Definitions of arguments for argp functions.  */
static const struct argp_option options[] =
{
  { "print-cache", 'p', NULL, 0, N_("Print cache"), 0},
  { "verbose", 'v', NULL, 0, N_("Generate verbose messages"), 0},
  { NULL, 'N', NULL, 0, N_("Don't build cache"), 0},
  { NULL, 'X', NULL, 0, N_("Don't generate links"), 0},
  { NULL, 'r', "ROOT", 0, N_("Change to and use ROOT as root directory"), 0},
  { NULL, 'C', "CACHE", 0, N_("Use CACHE as cache file"), 0},
  { NULL, 'f', "CONF", 0, N_("Use CONF as configuration file"), 0},
  { NULL, 'n', NULL, 0, N_("Only process directories specified on the command line.  Don't build cache."), 0},
  { NULL, 'l', NULL, 0, N_("Manually link individual libraries."), 0},
  { "format", 'c', "FORMAT", 0, N_("Format to use: new, old or compat (default)"), 0},
  { NULL, 0, NULL, 0, NULL, 0 }
};

/* Short description of program.  */
static const char doc[] = N_("Configure Dynamic Linker Run Time Bindings.");

/* Prototype for option handler.  */
static error_t parse_opt (int key, char *arg, struct argp_state *state);

/* Data structure to communicate with argp functions.  */
static struct argp argp =
{
  options, parse_opt, NULL, doc, NULL, NULL, NULL
};

/* Check if string corresponds to an important hardware capability.  */
static int
is_hwcap (const char *name)
{
  int hwcap_idx = _dl_string_hwcap (name);

  if (hwcap_idx != -1 && ((1 << hwcap_idx) & HWCAP_IMPORTANT))
    return 1;
  return 0;
}

/* Get hwcap encoding of path.  */
static unsigned long int
path_hwcap (const char *path)
{
  char *str = xstrdup (path);
  char *ptr;
  unsigned long int hwcap = 0;
  unsigned long int h;

  size_t len;

  len = strlen (str);
  if (str[len] == '/')
    str[len] = '\0';

  /* Search pathname from the end and check for hwcap strings.  */
  for (;;)
    {
      ptr = strrchr (str, '/');

      if (ptr == NULL)
	break;

      h = _dl_string_hwcap (ptr+1);

      if (h == -1)
	break;
      hwcap += 1 << h;

      /* Search the next part of the path.  */
      *ptr = '\0';
    }

  free (str);
  return hwcap;
}

/* Handle program arguments.  */
static error_t
parse_opt (int key, char *arg, struct argp_state *state)
{
  switch (key)
    {
    case 'C':
      cache_file = arg;
      break;
    case 'f':
      config_file = arg;
      break;
    case 'l':
      opt_manual_link = 1;
      break;
    case 'N':
      opt_build_cache = 0;
      break;
    case 'n':
      opt_build_cache = 0;
      opt_only_cline = 1;
      break;
    case 'p':
      opt_print_cache = 1;
      break;
    case 'r':
      opt_chroot = arg;
      break;
    case 'v':
      opt_verbose = 1;
      break;
    case 'X':
      opt_link = 0;
      break;
    case 'c':
      if (strcmp (arg, "old") == 0)
	opt_format = 0;
      else if (strcmp (arg, "compat") == 0)
	opt_format = 1;
      else if (strcmp (arg, "new") == 0)
	opt_format = 2;
      break;
    default:
      return ARGP_ERR_UNKNOWN;
    }

  return 0;
}

/* Print the version information.  */
static void
print_version (FILE *stream, struct argp_state *state)
{
  fprintf (stream, "ldconfig (GNU %s) %s\n", PACKAGE, VERSION);
  fprintf (stream, gettext ("\
Copyright (C) %s Free Software Foundation, Inc.\n\
This is free software; see the source for copying conditions.  There is NO\n\
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
"), "2000");
  fprintf (stream, gettext ("Written by %s.\n"),
	   "Andreas Jaeger");
}

/* Add a single directory entry.  */
static void
add_single_dir (struct dir_entry *entry, int verbose)
{
  struct dir_entry *ptr, *prev;

  ptr = dir_entries;
  prev = ptr;
  while (ptr != NULL)
    {
      /* Check for duplicates.  */
      if (strcmp (ptr->path, entry->path) == 0)
	{
	  if (opt_verbose && verbose)
	    error (0, 0, _("Path `%s' given more than once"), entry->path);
	  /* Use the newer information.  */
	  ptr->flag = entry->flag;
	  free (entry);
	  break;
	}
      prev = ptr;
      ptr = ptr->next;
    }
  /* Is this the first entry?  */
  if (ptr == NULL && dir_entries == NULL)
    dir_entries = entry;
  else if (ptr == NULL)
    prev->next = entry;
}

/* Add one directory to the list of directories to process.  */
static void
add_dir (const char *line)
{
  char *equal_sign;
  struct dir_entry *entry;
  unsigned int i;

  entry = xmalloc (sizeof (struct dir_entry));
  entry->next = NULL;

  /* Search for an '=' sign.  */
  entry->path = xstrdup (line);
  equal_sign = strchr (entry->path, '=');
  if (equal_sign)
    {
      *equal_sign = '\0';
      ++equal_sign;
      entry->flag = FLAG_ANY;
      for (i = 0; i < sizeof (lib_types) / sizeof (lib_types [0]); ++i)
	if (strcmp (equal_sign, lib_types[i].name) == 0)
	  {
	    entry->flag = lib_types[i].flag;
	    break;
	  }
      if (entry->flag == FLAG_ANY)
	error (0, 0, _("%s is not a known library type"), equal_sign);
    }
  else
    {
      entry->flag = FLAG_ANY;
    }

  /* Canonify path: for now only remove trailing slashes.  */
  i = strlen (entry->path) - 1;
  while (entry->path[i] == '/' && i > 0)
    {
      entry->path [i] = '\0';
      --i;
    }

  add_single_dir (entry, 1);
}


static int
chroot_stat (const char *real_path, const char *path, struct stat64 *st)
{
  int ret;
  char *canon_path;

  if (!opt_chroot)
    return stat64 (real_path, st);

  ret = lstat64 (real_path, st);
  if (ret || !S_ISLNK (st->st_mode))
    return ret;

  canon_path = chroot_canon (opt_chroot, path);
  if (canon_path == NULL)
    return -1;

  ret = stat64 (canon_path, st);
  free (canon_path);
  return ret;
}

/* Create a symbolic link from soname to libname in directory path.  */
static void
create_links (const char *real_path, const char *path, const char *libname,
	      const char *soname)
{
  char *full_libname, *full_soname;
  char *real_full_libname, *real_full_soname;
  struct stat64 stat_lib, stat_so, lstat_so;
  int do_link = 1;
  int do_remove = 1;
  /* XXX: The logics in this function should be simplified.  */

  /* Get complete path.  */
  full_libname = alloca (strlen (path) + strlen (libname) + 2);
  full_soname = alloca (strlen (path) + strlen (libname) + 2);
  sprintf (full_libname, "%s/%s", path, libname);
  sprintf (full_soname, "%s/%s", path, soname);
  if (opt_chroot)
    {
      real_full_libname = alloca (strlen (real_path) + strlen (libname) + 2);
      real_full_soname = alloca (strlen (real_path) + strlen (libname) + 2);
      sprintf (real_full_libname, "%s/%s", real_path, libname);
      sprintf (real_full_soname, "%s/%s", real_path, soname);
    }
  else
    {
      real_full_libname = full_libname;
      real_full_soname = full_soname;
    }

  /* Does soname already exist and point to the right library?  */
  if (chroot_stat (real_full_soname, full_soname, &stat_so) == 0)
    {
      if (chroot_stat (real_full_libname, full_libname, &stat_lib))
	{
	  error (0, 0, _("Can't stat %s\n"), full_libname);
	  return;
	}
      if (stat_lib.st_dev == stat_so.st_dev
	  && stat_lib.st_ino == stat_so.st_ino)
	/* Link is already correct.  */
	do_link = 0;
      else if (lstat64 (full_soname, &lstat_so) == 0
	       && !S_ISLNK (lstat_so.st_mode))
	{
	  error (0, 0, _("%s is not a symbolic link\n"), full_soname);
	  do_link = 0;
	  do_remove = 0;
	}
    }
  else if (lstat64 (real_full_soname, &lstat_so) != 0
	   || !S_ISLNK (lstat_so.st_mode))
    /* Unless it is a stale symlink, there is no need to remove.  */
    do_remove = 0;

  if (opt_verbose)
    printf ("\t%s -> %s", soname, libname);

  if (do_link && opt_link)
    {
      /* Remove old link.  */
      if (do_remove)
	if (unlink (real_full_soname))
	  {
	    error (0, 0, _("Can't unlink %s"), full_soname);
	    do_link = 0;
	  }
      /* Create symbolic link.  */
      if (do_link && symlink (libname, real_full_soname))
	{
	  error (0, 0, _("Can't link %s to %s"), full_soname, libname);
	  do_link = 0;
	}
      if (opt_verbose)
	{
	  if (do_link)
	    fputs (_(" (changed)\n"), stdout);
	  else
	    fputs (_(" (SKIPPED)\n"), stdout);
	}
    }
  else if (opt_verbose)
    fputs ("\n", stdout);
}

/* Manually link the given library.  */
static void
manual_link (char *library)
{
  char *path;
  char *real_path;
  char *real_library;
  char *libname;
  char *soname;
  struct stat64 stat_buf;
  int flag;

  /* Prepare arguments for create_links call.  Split library name in
     directory and filename first.  Since path is allocated, we've got
     to be careful to free at the end.  */
  path = xstrdup (library);
  libname = strrchr (path, '/');

  if (libname)
    {
      /* Successfully split names.  Check if path is just "/" to avoid
         an empty path.  */
      if (libname == path)
	{
	  libname = library + 1;
	  path = xrealloc (path, 2);
	  strcpy (path, "/");
	}
      else
	{
	  *libname = '\0';
	  ++libname;
	}
    }
  else
    {
      /* There's no path, construct one. */
      libname = library;
      path = xrealloc (path, 2);
      strcpy (path, ".");
    }

  if (opt_chroot)
    {
      real_path = chroot_canon (opt_chroot, path);
      if (real_path == NULL)
	{
	  error (0, errno, _("Can't find %s"), path);
	  free (path);
	  return;
	}
      real_library = alloca (strlen (real_path) + strlen (libname) + 2);
      sprintf (real_library, "%s/%s", real_path, libname);
    }
  else
    {
      real_path = path;
      real_library = library;
    }

  /* Do some sanity checks first.  */
  if (lstat64 (real_library, &stat_buf))
    {
      error (0, errno, _("Can't lstat %s"), library);
      free (path);
      return;
    }
  /* We don't want links here!  */
  else if (!S_ISREG (stat_buf.st_mode))
    {
      error (0, 0, _("Ignored file %s since it is not a regular file."),
	     library);
      free (path);
      return;
    }
  if (process_file (real_library, library, libname, &flag, &soname, 0))
    {
      error (0, 0, _("No link created since soname could not be found for %s"),
	     library);
      free (path);
      return;
    }
  create_links (real_path, path, libname, soname);
  free (soname);
  free (path);
}


/* Read a whole directory and search for libraries.
   The purpose is two-fold:
   - search for libraries which will be added to the cache
   - create symbolic links to the soname for each library

   This has to be done separatly for each directory.

   To keep track of which libraries to add to the cache and which
   links to create, we save a list of all libraries.

   The algorithm is basically:
   for all libraries in the directory do
     get soname of library
     if soname is already in list
       if new library is newer, replace entry
       otherwise ignore this library
     otherwise add library to list

   For example, if the two libraries libxy.so.1.1 and libxy.so.1.2
   exist and both have the same soname, e.g. libxy.so, a symbolic link
   is created from libxy.so.1.2 (the newer one) to libxy.so.
   libxy.so.1.2 and libxy.so are added to the cache - but not
   libxy.so.1.1.  */

/* Information for one library.  */
struct dlib_entry
{
  char *name;
  char *soname;
  int flag;
  int is_link;
  struct dlib_entry *next;
};


static void
search_dir (const struct dir_entry *entry)
{
  DIR *dir;
  struct dirent *direntry;
  char *file_name, *dir_name, *real_file_name, *real_name;
  int file_name_len, real_file_name_len, len;
  char *soname;
  struct dlib_entry *dlibs;
  struct dlib_entry *dlib_ptr;
  struct stat64 stat_buf;
  int is_link;
  unsigned long int hwcap = path_hwcap (entry->path);

  file_name_len = PATH_MAX;
  file_name = alloca (file_name_len);

  dlibs = NULL;

  if (opt_verbose)
    {
      if (hwcap != 0)
	printf ("%s: (hwcap: 0x%lx)\n", entry->path, hwcap);
      else
	printf ("%s:\n", entry->path);
    }

  if (opt_chroot)
    {
      dir_name = chroot_canon (opt_chroot, entry->path);
      real_file_name_len = PATH_MAX;
      real_file_name = alloca (real_file_name_len);
    }
  else
    {
      dir_name = entry->path;
      real_file_name_len = 0;
      real_file_name = file_name;
    }

  if (dir_name == NULL || (dir = opendir (dir_name)) == NULL)
    {
      if (opt_verbose)
	error (0, errno, _("Can't open directory %s"), entry->path);
      if (opt_chroot && dir_name)
	free (dir_name);
      return;
    }

  while ((direntry = readdir (dir)) != NULL)
    {
      int flag;
#ifdef _DIRENT_HAVE_D_TYPE
      /* We only look at links and regular files.  */
      if (direntry->d_type != DT_UNKNOWN
	  && direntry->d_type != DT_LNK
	  && direntry->d_type != DT_REG
	  && direntry->d_type != DT_DIR)
	continue;
#endif /* _DIRENT_HAVE_D_TYPE  */
      /* Does this file look like a shared library or is it a hwcap
	 subdirectory?  The dynamic linker is also considered as
	 shared library.  */
      if (((strncmp (direntry->d_name, "lib", 3) != 0
	    && strncmp (direntry->d_name, "ld-", 3) != 0)
	   || strstr (direntry->d_name, ".so") == NULL)
	  && !is_hwcap (direntry->d_name))
	continue;
      len = strlen (entry->path) + strlen (direntry->d_name);
      if (len > file_name_len)
	{
	  file_name_len = len + 1;
	  file_name = alloca (file_name_len);
	  if (!opt_chroot)
	    real_file_name = file_name;
	}
      sprintf (file_name, "%s/%s", entry->path, direntry->d_name);
      if (opt_chroot)
	{
	  len = strlen (dir_name) + strlen (direntry->d_name);
	  if (len > real_file_name_len)
	    {
	      real_file_name_len = len + 1;
	      real_file_name = alloca (real_file_name_len);
	    }
	  sprintf (real_file_name, "%s/%s", dir_name, direntry->d_name);
	}
#ifdef _DIRENT_HAVE_D_TYPE
      if (direntry->d_type != DT_UNKNOWN)
	stat_buf.st_mode = DTTOIF (direntry->d_type);
      else
#endif
	if (lstat64 (real_file_name, &stat_buf))
	  {
	    error (0, errno, _("Can't lstat %s"), file_name);
	    continue;
	  }

      if (S_ISDIR (stat_buf.st_mode) && is_hwcap (direntry->d_name))
	{
	  /* Handle subdirectory later.  */
	  struct dir_entry *new_entry;

	  new_entry = xmalloc (sizeof (struct dir_entry));
	  new_entry->path = xstrdup (file_name);
	  new_entry->flag = entry->flag;
	  new_entry->next = NULL;
	  add_single_dir (new_entry, 0);
	  continue;
	}
      else if (!S_ISREG (stat_buf.st_mode) && !S_ISLNK (stat_buf.st_mode))
	continue;

      is_link = S_ISLNK (stat_buf.st_mode);
      if (opt_chroot && is_link)
	{
	  real_name = chroot_canon (opt_chroot, file_name);
	  if (real_name == NULL)
	    {
	      if (strstr (file_name, ".so") == NULL)
		error (0, 0, _("Input file %s not found.\n"), file_name);
	      continue;
	    }
	}
      else
	real_name = real_file_name;

      if (process_file (real_name, file_name, direntry->d_name, &flag,
			&soname, is_link))
	{
	  if (real_name != real_file_name)
	    free (real_name);
	  continue;
	}

      if (real_name != real_file_name)
	free (real_name);

      /* Links will just point to itself.  */
      if (is_link)
	{
	  free (soname);
	  soname = xstrdup (direntry->d_name);
	}

      if (flag == FLAG_ELF
	  && (entry->flag == FLAG_ELF_LIBC5
	      || entry->flag == FLAG_ELF_LIBC6))
	flag = entry->flag;
      /* Some sanity checks to print warnings.  */
      if (opt_verbose)
	{
	  if (flag == FLAG_ELF_LIBC5 && entry->flag != FLAG_ELF_LIBC5
	      && entry->flag != FLAG_ANY)
	    error (0, 0, _("libc5 library %s in wrong directory"), file_name);
	  if (flag == FLAG_ELF_LIBC6 && entry->flag != FLAG_ELF_LIBC6
	      && entry->flag != FLAG_ANY)
	    error (0, 0, _("libc6 library %s in wrong directory"), file_name);
	  if (flag == FLAG_LIBC4 && entry->flag != FLAG_LIBC4
	      && entry->flag != FLAG_ANY)
	    error (0, 0, _("libc4 library %s in wrong directory"), file_name);
	}

      /* Add library to list.  */
      for (dlib_ptr = dlibs; dlib_ptr != NULL; dlib_ptr = dlib_ptr->next)
	{
	  /* Is soname already in list?  */
	  if (strcmp (dlib_ptr->soname, soname) == 0)
	    {
	      /* Prefer a file to a link, otherwise check which one
		 is newer.  */
	      if ((!is_link && dlib_ptr->is_link)
		  || (is_link == dlib_ptr->is_link
		      && _dl_cache_libcmp (dlib_ptr->name, direntry->d_name) < 0))
		{
		  /* It's newer - add it.  */
		  /* Flag should be the same - sanity check.  */
		  if (dlib_ptr->flag != flag)
		    {
		      if (dlib_ptr->flag == FLAG_ELF
			  && (flag == FLAG_ELF_LIBC5 || flag == FLAG_ELF_LIBC6))
			dlib_ptr->flag = flag;
		      else if ((dlib_ptr->flag == FLAG_ELF_LIBC5
				|| dlib_ptr->flag == FLAG_ELF_LIBC6)
			       && flag == FLAG_ELF)
			dlib_ptr->flag = flag;
		      else
			error (0, 0, _("libraries %s and %s in directory %s have same soname but different type."),
			       dlib_ptr->name, direntry->d_name, entry->path);
		    }
		  free (dlib_ptr->name);
		  dlib_ptr->name = xstrdup (direntry->d_name);
		  dlib_ptr->is_link = is_link;
		}
	      /* Don't add this library, abort loop.  */
	      /* Also free soname, since it's dynamically allocated.  */
	      free (soname);
	      break;
	    }
	}
      /* Add the library if it's not already in.  */
      if (dlib_ptr == NULL)
	{
	  dlib_ptr = (struct dlib_entry *)xmalloc (sizeof (struct dlib_entry));
	  dlib_ptr->name = xstrdup (direntry->d_name);
	  dlib_ptr->flag = flag;
	  dlib_ptr->soname = soname;
	  dlib_ptr->is_link = is_link;
	  /* Add at head of list.  */
	  dlib_ptr->next = dlibs;
	  dlibs = dlib_ptr;
	}
    }

  closedir (dir);

  /* Now dlibs contains a list of all libs - add those to the cache
     and created all symbolic links.  */
  for (dlib_ptr = dlibs; dlib_ptr != NULL; dlib_ptr = dlib_ptr->next)
    {
      /* Don't create links to links.  */
      if (dlib_ptr->is_link == 0)
	create_links (dir_name, entry->path, dlib_ptr->name,
		      dlib_ptr->soname);
      if (opt_build_cache)
	add_to_cache (entry->path, dlib_ptr->soname, dlib_ptr->flag, hwcap);
    }

  /* Free all resources.  */
  while (dlibs)
    {
      dlib_ptr = dlibs;
      free (dlib_ptr->soname);
      free (dlib_ptr->name);
      dlibs = dlibs->next;
      free (dlib_ptr);
    }

  if (opt_chroot && dir_name)
    free (dir_name);
}

/* Search through all libraries.  */
static void
search_dirs (void)
{
  struct dir_entry *entry;

  for (entry = dir_entries; entry != NULL; entry = entry->next)
    search_dir (entry);

  /* Free all allocated memory.  */
  while (dir_entries)
    {
      entry = dir_entries;
      dir_entries = dir_entries->next;
      free (entry->path);
      free (entry);
    }
}


/* Parse configuration file.  */
static void
parse_conf (const char *filename)
{
  FILE *file = NULL;
  char *line = NULL;
  const char *canon;
  size_t len = 0;

  if (opt_chroot)
    {
      canon = chroot_canon (opt_chroot, filename);
      if (canon)
	file = fopen (canon, "r");
      else
	canon = filename;
    }
  else
    {
      canon = filename;
      file = fopen (filename, "r");
    }

  if (file == NULL)
    {
      error (0, errno, _("Can't open configuration file %s"), canon);
      if (canon != filename)
	free ((char *) canon);
      return;
    }

  if (canon != filename)
    free ((char *) canon);

  do
    {
      ssize_t n = getline (&line, &len, file);
      if (n < 0)
	break;

      if (line[n - 1] == '\n')
	line[n - 1] = '\0';

      /* Because the file format does not know any form of quoting we
	 can search forward for the next '#' character and if found
	 make it terminating the line.  */
      *strchrnul (line, '#') = '\0';

      /* If the line is blank it is ignored.  */
      if (line[0] == '\0')
	continue;

      add_dir (line);
    } while (!feof (file));

  /* Free buffer and close file.  */
  free (line);
  fclose (file);
}


int
main (int argc, char **argv)
{
  int remaining;

  /* Parse and process arguments.  */
  argp_parse (&argp, argc, argv, 0, &remaining, NULL);

  /* Remaining arguments are additional libraries if opt_manual_link
     is not set.  */
  if (remaining != argc && !opt_manual_link)
    {
      int i;
      for (i = remaining; i < argc; ++i)
	add_dir (argv [i]);
    }

  if (opt_chroot)
    {
      /* Normalize the path a bit, we might need it for printing later.  */
      char *endp = strchr (opt_chroot, '\0');
      while (endp > opt_chroot && endp[-1] == '/')
	--endp;
      *endp = '\0';
      if (endp == opt_chroot)
	opt_chroot = NULL;

      if (opt_chroot)
	{
	  /* It is faster to use chroot if we can.  */
	  if (!chroot (opt_chroot))
	    {
	      if (chdir ("/"))
		error (EXIT_FAILURE, errno, _("Can't chdir to /"));
	      opt_chroot = NULL;
	    }
	}
    }

  if (cache_file == NULL)
    {
      cache_file = alloca (strlen (LD_SO_CACHE) + 1);
      strcpy (cache_file, LD_SO_CACHE);
    }

  if (config_file == NULL)
    config_file = LD_SO_CONF;

  if (opt_print_cache)
    {
      if (opt_chroot)
	{
	  char *p = chroot_canon (opt_chroot, cache_file);
	  if (p == NULL)
	    error (EXIT_FAILURE, errno, _("Can't open cache file %s\n"),
		   cache_file);
	  cache_file = p;
	}
      print_cache (cache_file);
      if (opt_chroot)
	free (cache_file);
      exit (0);
    }

  if (opt_chroot)
    {
      /* Canonicalize the directory name of cache_file, not cache_file,
         because we'll rename a temporary cache file to it.  */
      char *p = strrchr (cache_file, '/');
      char *canon = chroot_canon (opt_chroot,
				  p ? (*p = '\0', cache_file) : "/");

      if (canon == NULL)
	{
	  error (EXIT_FAILURE, errno,
		 _("Can't open cache file directory %s\n"),
		 p ? cache_file : "/");
	}

      if (p)
	++p;
      else
	p = cache_file;

      cache_file = alloca (strlen (canon) + strlen (p) + 2);
      sprintf (cache_file, "%s/%s", canon, p);
      free (canon);
    }

  if (opt_manual_link)
    {
      /* Link all given libraries manually.  */
      int i;

      for (i = remaining; i < argc; ++i)
	manual_link (argv [i]);

      exit (0);
    }


  if (opt_build_cache)
    init_cache ();

  if (!opt_only_cline)
    {
      /* Always add the standard search paths.  */
      add_dir (SLIBDIR);
      if (strcmp (SLIBDIR, LIBDIR))
	add_dir (LIBDIR);

      parse_conf (config_file);
    }

  search_dirs ();

  if (opt_build_cache)
    save_cache (cache_file);

  return 0;
}