glibc/elf/cache.c

/* Copyright (C) 1999-2003,2005,2006 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Andreas Jaeger <aj@suse.de>, 1999.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 2 as
   published by the Free Software Foundation.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#include <errno.h>
#include <error.h>
#include <dirent.h>
#include <inttypes.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>

struct cache_entry
{
  char *lib;			/* Library name.  */
  char *path;			/* Path to find library.  */
  int flags;			/* Flags to indicate kind of library.  */
  unsigned int osversion;	/* Required OS version.  */
  uint64_t hwcap;		/* Important hardware capabilities.  */
  int bits_hwcap;		/* Number of bits set in hwcap.  */
  struct cache_entry *next;	/* Next entry in list.  */
};

/* List of all cache entries.  */
static struct cache_entry *entries;

static const char *flag_descr[] =
{ "libc4", "ELF", "libc5", "libc6"};

/* Print a single entry.  */
static void
print_entry (const char *lib, int flag, unsigned int osversion,
	     uint64_t hwcap, const char *key)
{
  printf ("\t%s (", lib);
  switch (flag & FLAG_TYPE_MASK)
    {
    case FLAG_LIBC4:
    case FLAG_ELF:
    case FLAG_ELF_LIBC5:
    case FLAG_ELF_LIBC6:
      fputs (flag_descr[flag & FLAG_TYPE_MASK], stdout);
      break;
    default:
      fputs (_("unknown"), stdout);
      break;
    }
  switch (flag & FLAG_REQUIRED_MASK)
    {
    case FLAG_SPARC_LIB64:
      fputs (",64bit", stdout);
      break;
    case FLAG_IA64_LIB64:
      fputs (",IA-64", stdout);
      break;
    case FLAG_X8664_LIB64:
      fputs (",x86-64", stdout);
      break;
    case FLAG_S390_LIB64:
      fputs(",64bit", stdout);
      break;
    case FLAG_POWERPC_LIB64:
      fputs(",64bit", stdout);
      break;
    case FLAG_MIPS64_LIBN32:
      fputs(",N32", stdout);
      break;
    case FLAG_MIPS64_LIBN64:
      fputs(",64bit", stdout);
    case 0:
      break;
    default:
      printf (",%d", flag & FLAG_REQUIRED_MASK);
      break;
    }
  if (hwcap != 0)
    printf (", hwcap: %#.16" PRIx64, hwcap);
  if (osversion != 0)
    {
      static const char *const abi_tag_os[] =
      {
	[0] = "Linux",
	[1] = "Hurd",
	[2] = "Solaris",
	[3] = "FreeBSD",
	[4] = "kNetBSD",
	[5] = "Syllable",
	[6] = N_("Unknown OS")
      };
#define MAXTAG (sizeof abi_tag_os / sizeof abi_tag_os[0] - 1)
      unsigned int os = osversion >> 24;

      printf (_(", OS ABI: %s %d.%d.%d"),
	      _(abi_tag_os[os > MAXTAG ? MAXTAG : os]),
	      (osversion >> 16) & 0xff,
	      (osversion >> 8) & 0xff,
	      osversion & 0xff);
    }
  printf (") => %s\n", key);
}


/* Print the whole cache file, if a file contains the new cache format
   hidden in the old one, print the contents of the new format.  */
void
print_cache (const char *cache_name)
{
  size_t cache_size;
  struct stat64 st;
  int fd;
  unsigned int i;
  struct cache_file *cache;
  struct cache_file_new *cache_new = NULL;
  const char *cache_data;
  int format = 0;

  fd = open (cache_name, O_RDONLY);
  if (fd < 0)
    error (EXIT_FAILURE, errno, _("Can't open cache file %s\n"), cache_name);

  if (fstat64 (fd, &st) < 0
      /* No need to map the file if it is empty.  */
      || st.st_size == 0)
    {
      close (fd);
      return;
    }

  cache = mmap (0, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
  if (cache == MAP_FAILED)
    error (EXIT_FAILURE, errno, _("mmap of cache file failed.\n"));
  cache_size = st.st_size;

  if (cache_size < sizeof (struct cache_file))
    error (EXIT_FAILURE, 0, _("File is not a cache file.\n"));

  if (memcmp (cache->magic, CACHEMAGIC, sizeof CACHEMAGIC - 1))
    {
      /* This can only be the new format without the old one.  */
      cache_new = (struct cache_file_new *) cache;

      if (memcmp (cache_new->magic, CACHEMAGIC_NEW, sizeof CACHEMAGIC_NEW - 1)
	  || memcmp (cache_new->version, CACHE_VERSION,
		      sizeof CACHE_VERSION - 1))
	error (EXIT_FAILURE, 0, _("File is not a cache file.\n"));
      format = 1;
      /* This is where the strings start.  */
      cache_data = (const char *) cache_new;
    }
  else
    {
      size_t offset = ALIGN_CACHE (sizeof (struct cache_file)
				   + (cache->nlibs
				      * sizeof (struct file_entry)));
      /* This is where the strings start.  */
      cache_data = (const char *) &cache->libs[cache->nlibs];

      /* Check for a new cache embedded in the old format.  */
      if (cache_size >
	  (offset + sizeof (struct cache_file_new)))
	{

	  cache_new = (struct cache_file_new *) ((void *)cache + offset);

	  if (memcmp (cache_new->magic, CACHEMAGIC_NEW,
		      sizeof CACHEMAGIC_NEW - 1) == 0
	      && memcmp (cache_new->version, CACHE_VERSION,
			 sizeof CACHE_VERSION - 1) == 0)
	    {
	      cache_data = (const char *) cache_new;
	      format = 1;
	    }
	}
    }

  if (format == 0)
    {
      printf (_("%d libs found in cache `%s'\n"), cache->nlibs, cache_name);

      /* Print everything.  */
      for (i = 0; i < cache->nlibs; i++)
	print_entry (cache_data + cache->libs[i].key,
		     cache->libs[i].flags, 0, 0,
		     cache_data + cache->libs[i].value);
    }
  else if (format == 1)
    {
      printf (_("%d libs found in cache `%s'\n"),
	      cache_new->nlibs, cache_name);

      /* Print everything.  */
      for (i = 0; i < cache_new->nlibs; i++)
	print_entry (cache_data + cache_new->libs[i].key,
		     cache_new->libs[i].flags,
		     cache_new->libs[i].osversion,
		     cache_new->libs[i].hwcap,
		     cache_data + cache_new->libs[i].value);
    }
  /* Cleanup.  */
  munmap (cache, cache_size);
  close (fd);
}

/* Initialize cache data structures.  */
void
init_cache (void)
{
  entries = NULL;
}



static
int compare (const struct cache_entry *e1, const struct cache_entry *e2)
{
  int res;

  /* We need to swap entries here to get the correct sort order.  */
  res = _dl_cache_libcmp (e2->lib, e1->lib);
  if (res == 0)
    {
      if (e1->flags < e2->flags)
	return 1;
      else if (e1->flags > e2->flags)
	return -1;
      /* Sort by most specific hwcap.  */
      else if (e2->bits_hwcap > e1->bits_hwcap)
	return 1;
      else if (e2->bits_hwcap < e1->bits_hwcap)
	return -1;
      else if (e2->hwcap > e1->hwcap)
	return 1;
      else if (e2->hwcap < e1->hwcap)
	return -1;
      if (e2->osversion > e1->osversion)
	return 1;
      if (e2->osversion < e1->osversion)
	return -1;
    }
  return res;
}

/* Save the contents of the cache.  */
void
save_cache (const char *cache_name)
{
  struct cache_entry *entry;
  int fd, idx_old, idx_new;
  size_t total_strlen, len;
  char *strings, *str, *temp_name;
  struct cache_file *file_entries = NULL;
  struct cache_file_new *file_entries_new = NULL;
  size_t file_entries_size = 0;
  size_t file_entries_new_size = 0;
  unsigned int str_offset;
  /* Number of cache entries.  */
  int cache_entry_count = 0;
  /* Number of normal cache entries.  */
  int cache_entry_old_count = 0;
  /* Pad for alignment of cache_file_new.  */
  size_t pad;

  /* The cache entries are sorted already, save them in this order. */

  /* Count the length of all strings.  */
  /* The old format doesn't contain hwcap entries and doesn't contain
     libraries in subdirectories with hwcaps entries.  Count therefore
     also all entries with hwcap == 0.  */
  total_strlen = 0;
  for (entry = entries; entry != NULL; entry = entry->next)
    {
      /* Account the final NULs.  */
      total_strlen += strlen (entry->lib) + strlen (entry->path) + 2;
      ++cache_entry_count;
      if (entry->hwcap == 0)
	++cache_entry_old_count;
    }

  /* Create the on disk cache structure.  */
  /* First an array for all strings.  */
  strings = (char *)xmalloc (total_strlen);

  if (opt_format != 2)
    {
      /* struct cache_file_new is 64-bit aligned on some arches while
	 only 32-bit aligned on other arches.  Duplicate last old
	 cache entry so that new cache in ld.so.cache can be used by
	 both.  */
      if (opt_format != 0)
	cache_entry_old_count = (cache_entry_old_count + 1) & ~1;

      /* And the list of all entries in the old format.  */
      file_entries_size = sizeof (struct cache_file)
	+ cache_entry_old_count * sizeof (struct file_entry);
      file_entries = (struct cache_file *) xmalloc (file_entries_size);

      /* Fill in the header.  */
      memset (file_entries, 0, sizeof (struct cache_file));
      memcpy (file_entries->magic, CACHEMAGIC, sizeof CACHEMAGIC - 1);

      file_entries->nlibs = cache_entry_old_count;
    }

  if (opt_format != 0)
    {
      /* And the list of all entries in the new format.  */
      file_entries_new_size = sizeof (struct cache_file_new)
	+ cache_entry_count * sizeof (struct file_entry_new);
      file_entries_new =
	(struct cache_file_new *) xmalloc (file_entries_new_size);

      /* Fill in the header.  */
      memset (file_entries_new, 0, sizeof (struct cache_file_new));
      memcpy (file_entries_new->magic, CACHEMAGIC_NEW,
	      sizeof CACHEMAGIC_NEW - 1);
      memcpy (file_entries_new->version, CACHE_VERSION,
	      sizeof CACHE_VERSION - 1);

      file_entries_new->nlibs = cache_entry_count;
      file_entries_new->len_strings = total_strlen;
    }

  pad = ALIGN_CACHE (file_entries_size) - file_entries_size;

  /* If we have both formats, we hide the new format in the strings
     table, we have to adjust all string indices for this so that
     old libc5/glibc 2 dynamic linkers just ignore them.  */
  if (opt_format != 0)
    str_offset = file_entries_new_size;
  else
    str_offset = 0;

  str = strings;
  for (idx_old = 0, idx_new = 0, entry = entries; entry != NULL;
       entry = entry->next, ++idx_new)
    {
      /* First the library.  */
      if (opt_format != 2 && entry->hwcap == 0)
	{
	  file_entries->libs[idx_old].flags = entry->flags;
	  /* XXX: Actually we can optimize here and remove duplicates.  */
	  file_entries->libs[idx_old].key = str_offset + pad;
	}
      if (opt_format != 0)
	{
	  /* We could subtract file_entries_new_size from str_offset -
	     not doing so makes the code easier, the string table
	     always begins at the beginning of the the new cache
	     struct.  */
	  file_entries_new->libs[idx_new].flags = entry->flags;
	  file_entries_new->libs[idx_new].osversion = entry->osversion;
	  file_entries_new->libs[idx_new].hwcap = entry->hwcap;
	  file_entries_new->libs[idx_new].key = str_offset;
	}
      len = strlen (entry->lib);
      str = stpcpy (str, entry->lib);
      /* Account the final NUL.  */
      ++str;
      str_offset += len + 1;
      /* Then the path.  */
      if (opt_format != 2 && entry->hwcap == 0)
	file_entries->libs[idx_old].value = str_offset + pad;
      if (opt_format != 0)
	file_entries_new->libs[idx_new].value = str_offset;
      len = strlen (entry->path);
      str = stpcpy (str, entry->path);
      /* Account the final NUL.  */
      ++str;
      str_offset += len + 1;
      /* Ignore entries with hwcap for old format.  */
      if (entry->hwcap == 0)
	++idx_old;
    }

  /* Duplicate last old cache entry if needed.  */
  if (opt_format != 2
      && idx_old < cache_entry_old_count)
    file_entries->libs[idx_old] = file_entries->libs[idx_old - 1];

  /* Write out the cache.  */

  /* Write cache first to a temporary file and rename it later.  */
  temp_name = xmalloc (strlen (cache_name) + 2);
  sprintf (temp_name, "%s~", cache_name);
  /* First remove an old copy if it exists.  */
  if (unlink (temp_name) && errno != ENOENT)
    error (EXIT_FAILURE, errno, _("Can't remove old temporary cache file %s"),
	   temp_name);

  /* Create file.  */
  fd = open (temp_name, O_CREAT|O_WRONLY|O_TRUNC|O_NOFOLLOW,
	     S_IROTH|S_IRGRP|S_IRUSR|S_IWUSR);
  if (fd < 0)
    error (EXIT_FAILURE, errno, _("Can't create temporary cache file %s"),
	   temp_name);

  /* Write contents.  */
  if (opt_format != 2)
    {
      if (write (fd, file_entries, file_entries_size)
	  != (ssize_t) file_entries_size)
	error (EXIT_FAILURE, errno, _("Writing of cache data failed"));
    }
  if (opt_format != 0)
    {
      /* Align cache.  */
      if (opt_format != 2)
	{
	  char zero[pad];
	  memset (zero, '\0', pad);
	  if (write (fd, zero, pad) != (ssize_t) pad)
	    error (EXIT_FAILURE, errno, _("Writing of cache data failed"));
	}
      if (write (fd, file_entries_new, file_entries_new_size)
	  != (ssize_t) file_entries_new_size)
	error (EXIT_FAILURE, errno, _("Writing of cache data failed"));
    }

  if (write (fd, strings, total_strlen) != (ssize_t) total_strlen)
    error (EXIT_FAILURE, errno, _("Writing of cache data failed"));

  close (fd);

  /* Make sure user can always read cache file */
  if (chmod (temp_name, S_IROTH|S_IRGRP|S_IRUSR|S_IWUSR))
    error (EXIT_FAILURE, errno,
	   _("Changing access rights of %s to %#o failed"), temp_name,
	   S_IROTH|S_IRGRP|S_IRUSR|S_IWUSR);

  /* Move temporary to its final location.  */
  if (rename (temp_name, cache_name))
    error (EXIT_FAILURE, errno, _("Renaming of %s to %s failed"), temp_name,
	   cache_name);

  /* Free all allocated memory.  */
  free (file_entries_new);
  free (file_entries);
  free (strings);

  while (entries)
    {
      entry = entries;
      free (entry->path);
      free (entry->lib);
      entries = entries->next;
      free (entry);
    }
}


/* Add one library to the cache.  */
void
add_to_cache (const char *path, const char *lib, int flags,
	      unsigned int osversion, uint64_t hwcap)
{
  struct cache_entry *new_entry, *ptr, *prev;
  char *full_path;
  size_t len, i;

  new_entry = (struct cache_entry *) xmalloc (sizeof (struct cache_entry));

  len = strlen (lib) + strlen (path) + 2;

  full_path = (char *) xmalloc (len);
  snprintf (full_path, len, "%s/%s", path, lib);

  new_entry->lib = xstrdup (lib);
  new_entry->path = full_path;
  new_entry->flags = flags;
  new_entry->osversion = osversion;
  new_entry->hwcap = hwcap;
  new_entry->bits_hwcap = 0;

  /* Count the number of bits set in the masked value.  */
  for (i = 0; (~((1ULL << i) - 1) & hwcap) != 0 && i < 8 * sizeof (hwcap); ++i)
    if ((hwcap & (1ULL << i)) != 0)
      ++new_entry->bits_hwcap;


  /* Keep the list sorted - search for right place to insert.  */
  ptr = entries;
  prev = entries;
  while (ptr != NULL)
    {
      if (compare (ptr, new_entry) > 0)
	break;
      prev = ptr;
      ptr = ptr->next;
    }
  /* Is this the first entry?  */
  if (ptr == entries)
    {
      new_entry->next = entries;
      entries = new_entry;
    }
  else
    {
      new_entry->next = prev->next;
      prev->next = new_entry;
    }
}