path: root/elf/ldconfig.c

/* Copyright (C) 1999 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 <argp.h>
#include <dirent.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"

#ifndef LD_SO_CACHE
# define LD_SO_CACHE "/etc/ld.so.cache"
#endif

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

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

#define PACKAGE _libc_intl_domainname

struct lib_entry
  {
    int flags;
    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;

/* 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;

/* Cache file to use.  */
static const 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, 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
};



/* 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 '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;
    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\
"), "1999");
  fprintf (stream, gettext ("Written by %s.\n"),
	   "Andreas Jaeger");
}

/* Add one directory to the list of directories to process.  */
static void
add_dir (const char *line)
{
  char *equal_sign;
  struct dir_entry *entry, *ptr, *prev;
  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;
    }
  
  ptr = dir_entries;
  prev = ptr;
  while (ptr != NULL)
    {
      /* Check for duplicates.  */
      if (strcmp (ptr->path, entry->path) == 0)
	{
	  if (opt_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;
}


/* Create a symbolic link from soname to libname in directory path.  */
static void
create_links (const char *path, const char *libname, const char *soname)
{
  char full_libname [PATH_MAX], full_soname [PATH_MAX];
  struct stat 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.  */
  snprintf (full_libname, sizeof full_libname, "%s/%s", path, libname);
  snprintf (full_soname, sizeof full_soname, "%s/%s", path, soname);

  /* Does soname already exist and point to the right library?  */
  if (stat (full_soname, &stat_so) == 0)
    {
      if (stat (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 (lstat (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 (lstat (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 (full_soname))
	  {
	    error (0, 0, _("Can't unlink %s"), full_soname);
	    do_link = 0;
	  }
      /* Create symbolic link.  */
      if (do_link && symlink (libname, 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);
}

/* 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 buf [PATH_MAX];
  char *soname;
  struct dlib_entry *dlibs;
  struct dlib_entry *dlib_ptr;
  int nchars;
  struct stat stat_buf;
  int is_link;
  
  dlibs = NULL;

  if (opt_verbose)
    printf ("%s:\n", entry->path);
  
  dir = opendir (entry->path);
  if (dir == NULL)
    {
      if (opt_verbose)
	error (0, errno, _("Can't open directory %s"), entry->path);
      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)
	continue;
#endif /* _DIRENT_HAVE_D_TYPE  */

      /* Does this file look like a shared library?  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)
	continue;
      nchars = snprintf (buf, sizeof (buf), "%s/%s", entry->path,
			 direntry->d_name);
      /* Check for overflow.  */
      if (nchars >= (int) sizeof (buf))
	{
	  error (0, 0, _("buffer for snprintf too small for %s/%s--file is ignored\n"),
		 entry->path, direntry->d_name);
	  continue;
	}
      if (lstat (buf, &stat_buf))
	{
	  error (0, errno, _("Can't lstat %s"), buf);
	  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 (process_file (buf, direntry->d_name, &flag, &soname, is_link))
	continue;

      /* 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"), buf);
	  if (flag == FLAG_ELF_LIBC6 && entry->flag != FLAG_ELF_LIBC6
	      && entry->flag != FLAG_ANY)
	    error (0, 0, _("libc6 library %s in wrong directory"), buf);
	  if (flag == FLAG_LIBC4 && entry->flag != FLAG_LIBC4
	      && entry->flag != FLAG_ANY)
	    error (0, 0, _("libc4 library %s in wrong directory"), buf);
	}
      
      /* 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
		      && 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 (entry->path, dlib_ptr->name, dlib_ptr->soname);
      if (opt_build_cache)
	add_to_cache (entry->path, dlib_ptr->soname, dlib_ptr->flag);
    }

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

/* 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;
  char *line = NULL;
  size_t len = 0;
  
  file = fopen (filename, "r");

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

  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 (remaining != argc)
    {
      int i;
      for (i = remaining; i < argc; ++i)
	add_dir (argv [i]);
    }

  if (cache_file == NULL)
    cache_file = LD_SO_CACHE;

  if (config_file == NULL)
    config_file = LD_SO_CONF;
  
  /* Chroot first.  */
  if (opt_chroot)
    {
      if (chroot (opt_chroot))
	/* Report failure and exit program.  */
	error (EXIT_FAILURE, errno, _("Can't chroot to %s"), opt_chroot);
      /* chroot doesn't change the working directory, let's play safe.  */
      if (chdir ("/"))
	error (EXIT_FAILURE, errno, _("Can't chdir to /"));
    }

  if (opt_print_cache)
    {
      print_cache (cache_file);
      exit (0);
    }

  if (opt_build_cache)
    init_cache ();

  if (!opt_only_cline)
    {
      /* Always add the standard search paths.  */
      add_dir ("/lib");
      add_dir ("/usr/lib");

      parse_conf (config_file);
    }
  
  search_dirs ();

  if (opt_build_cache)
    save_cache (cache_file);

  return 0;
}