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dirinfo.c

/*
 * dirinfo.c --- maintains the directory information table for e2fsck.
 *
 * Copyright (C) 1993 Theodore Ts'o.  This file may be redistributed
 * under the terms of the GNU Public License.
 */

#undef DIRINFO_DEBUG

#include "e2fsck.h"
#include <sys/stat.h>
#include <fcntl.h>
#include "uuid/uuid.h"

#include <ext2fs/tdb.h>

struct dir_info_db {
      int         count;
      int         size;
      struct dir_info *array;
      struct dir_info *last_lookup;
      char        *tdb_fn;
      TDB_CONTEXT *tdb;
};

struct dir_info_iter {
      int   i;
      TDB_DATA    tdb_iter;
};

struct dir_info_ent {
      ext2_ino_t        dotdot;     /* Parent according to '..' */
      ext2_ino_t        parent; /* Parent according to treewalk */
};


static void e2fsck_put_dir_info(e2fsck_t ctx, struct dir_info *dir);

static void setup_tdb(e2fsck_t ctx, ext2_ino_t num_dirs)
{
      struct dir_info_db      *db = ctx->dir_info;
      unsigned int            threshold;
      errcode_t         retval;
      char              *tdb_dir, uuid[40];
      int               fd, enable;

      profile_get_string(ctx->profile, "scratch_files", "directory", 0, 0,
                     &tdb_dir);
      profile_get_uint(ctx->profile, "scratch_files",
                   "numdirs_threshold", 0, 0, &threshold);
      profile_get_boolean(ctx->profile, "scratch_files",
                      "dirinfo", 0, 1, &enable);

      if (!enable || !tdb_dir || access(tdb_dir, W_OK) ||
          (threshold && num_dirs <= threshold))
            return;

      retval = ext2fs_get_mem(strlen(tdb_dir) + 64, &db->tdb_fn);
      if (retval)
            return;

      uuid_unparse(ctx->fs->super->s_uuid, uuid);
      sprintf(db->tdb_fn, "%s/%s-dirinfo-XXXXXX", tdb_dir, uuid);
      fd = mkstemp(db->tdb_fn);
      db->tdb = tdb_open(db->tdb_fn, 0, TDB_CLEAR_IF_FIRST,
                     O_RDWR | O_CREAT | O_TRUNC, 0600);
      close(fd);
}

static void setup_db(e2fsck_t ctx)
{
      struct dir_info_db      *db;
      ext2_ino_t        num_dirs;
      errcode_t         retval;

      db = (struct dir_info_db *)
            e2fsck_allocate_memory(ctx, sizeof(struct dir_info_db),
                               "directory map db");
      db->count = db->size = 0;
      db->array = 0;

      ctx->dir_info = db;

      retval = ext2fs_get_num_dirs(ctx->fs, &num_dirs);
      if (retval)
            num_dirs = 1024;  /* Guess */

      setup_tdb(ctx, num_dirs);

      if (db->tdb) {
#ifdef DIRINFO_DEBUG
            printf("Note: using tdb!\n");
#endif
            return;
      }

      db->size = num_dirs + 10;
      db->array  = (struct dir_info *)
            e2fsck_allocate_memory(ctx, db->size
                               * sizeof (struct dir_info),
                               "directory map");
}

/*
 * This subroutine is called during pass1 to create a directory info
 * entry.  During pass1, the passed-in parent is 0; it will get filled
 * in during pass2.
 */
void e2fsck_add_dir_info(e2fsck_t ctx, ext2_ino_t ino, ext2_ino_t parent)
{
      struct dir_info_db      *db;
      struct dir_info   *dir, ent;
      int               i, j;
      errcode_t         retval;
      unsigned long           old_size;

#ifdef DIRINFO_DEBUG
      printf("add_dir_info for inode (%lu, %lu)...\n", ino, parent);
#endif
      if (!ctx->dir_info)
            setup_db(ctx);
      db = ctx->dir_info;

      if (ctx->dir_info->count >= ctx->dir_info->size) {
            old_size = ctx->dir_info->size * sizeof(struct dir_info);
            ctx->dir_info->size += 10;
            retval = ext2fs_resize_mem(old_size, ctx->dir_info->size *
                                 sizeof(struct dir_info),
                                 &ctx->dir_info->array);
            if (retval) {
                  ctx->dir_info->size -= 10;
                  return;
            }
      }

      ent.ino = ino;
      ent.parent = parent;
      ent.dotdot = parent;

      if (db->tdb) {
            e2fsck_put_dir_info(ctx, &ent);
            return;
      }

      /*
       * Normally, add_dir_info is called with each inode in
       * sequential order; but once in a while (like when pass 3
       * needs to recreate the root directory or lost+found
       * directory) it is called out of order.  In those cases, we
       * need to move the dir_info entries down to make room, since
       * the dir_info array needs to be sorted by inode number for
       * get_dir_info()'s sake.
       */
      if (ctx->dir_info->count &&
          ctx->dir_info->array[ctx->dir_info->count-1].ino >= ino) {
            for (i = ctx->dir_info->count-1; i > 0; i--)
                  if (ctx->dir_info->array[i-1].ino < ino)
                        break;
            dir = &ctx->dir_info->array[i];
            if (dir->ino != ino)
                  for (j = ctx->dir_info->count++; j > i; j--)
                        ctx->dir_info->array[j] = ctx->dir_info->array[j-1];
      } else
            dir = &ctx->dir_info->array[ctx->dir_info->count++];

      dir->ino = ino;
      dir->dotdot = parent;
      dir->parent = parent;
}

/*
 * get_dir_info() --- given an inode number, try to find the directory
 * information entry for it.
 */
static struct dir_info *e2fsck_get_dir_info(e2fsck_t ctx, ext2_ino_t ino)
{
      struct dir_info_db      *db = ctx->dir_info;
      int               low, high, mid;
      struct dir_info_ent     *buf;
      static struct dir_info  ret_dir_info;

      if (!db)
            return 0;

#ifdef DIRINFO_DEBUG
      printf("e2fsck_get_dir_info %d...", ino);
#endif

      if (db->tdb) {
            TDB_DATA key, data;

            key.dptr = (unsigned char *) &ino;
            key.dsize = sizeof(ext2_ino_t);

            data = tdb_fetch(db->tdb, key);
            if (!data.dptr) {
                  if (tdb_error(db->tdb) != TDB_ERR_NOEXIST)
                        printf("fetch failed: %s\n",
                               tdb_errorstr(db->tdb));
                  return 0;
            }

            buf = (struct dir_info_ent *) data.dptr;
            ret_dir_info.ino = ino;
            ret_dir_info.dotdot = buf->dotdot;
            ret_dir_info.parent = buf->parent;
#ifdef DIRINFO_DEBUG
            printf("(%d,%d,%d)\n", ino, buf->dotdot, buf->parent);
#endif
            free(data.dptr);
            return &ret_dir_info;
      }

      if (db->last_lookup && db->last_lookup->ino == ino)
            return db->last_lookup;

      low = 0;
      high = ctx->dir_info->count-1;
      if (ino == ctx->dir_info->array[low].ino) {
#ifdef DIRINFO_DEBUG
            printf("(%d,%d,%d)\n", ino,
                   ctx->dir_info->array[low].dotdot,
                   ctx->dir_info->array[low].parent);
#endif
            return &ctx->dir_info->array[low];
      }
      if (ino == ctx->dir_info->array[high].ino) {
#ifdef DIRINFO_DEBUG
            printf("(%d,%d,%d)\n", ino,
                   ctx->dir_info->array[high].dotdot,
                   ctx->dir_info->array[high].parent);
#endif
            return &ctx->dir_info->array[high];
      }

      while (low < high) {
            mid = (low+high)/2;
            if (mid == low || mid == high)
                  break;
            if (ino == ctx->dir_info->array[mid].ino) {
#ifdef DIRINFO_DEBUG
                  printf("(%d,%d,%d)\n", ino,
                         ctx->dir_info->array[mid].dotdot,
                         ctx->dir_info->array[mid].parent);
#endif
                  return &ctx->dir_info->array[mid];
            }
            if (ino < ctx->dir_info->array[mid].ino)
                  high = mid;
            else
                  low = mid;
      }
      return 0;
}

static void e2fsck_put_dir_info(e2fsck_t ctx, struct dir_info *dir)
{
      struct dir_info_db      *db = ctx->dir_info;
      struct dir_info_ent     buf;
      TDB_DATA          key, data;

#ifdef DIRINFO_DEBUG
      printf("e2fsck_put_dir_info (%d, %d, %d)...", dir->ino, dir->dotdot,
             dir->parent);
#endif

      if (!db->tdb)
            return;

      buf.parent = dir->parent;
      buf.dotdot = dir->dotdot;

      key.dptr = (unsigned char *) &dir->ino;
      key.dsize = sizeof(ext2_ino_t);
      data.dptr = (unsigned char *) &buf;
      data.dsize = sizeof(buf);

      if (tdb_store(db->tdb, key, data, TDB_REPLACE) == -1) {
            printf("store failed: %s\n", tdb_errorstr(db->tdb));
      }
      return;
}

/*
 * Free the dir_info structure when it isn't needed any more.
 */
void e2fsck_free_dir_info(e2fsck_t ctx)
{
      if (ctx->dir_info) {
            if (ctx->dir_info->tdb)
                  tdb_close(ctx->dir_info->tdb);
            if (ctx->dir_info->tdb_fn) {
                  unlink(ctx->dir_info->tdb_fn);
                  free(ctx->dir_info->tdb_fn);
            }
            ctx->dir_info->size = 0;
            ctx->dir_info->count = 0;
            ext2fs_free_mem(&ctx->dir_info);
            ctx->dir_info = 0;
      }
}

/*
 * Return the count of number of directories in the dir_info structure
 */
int e2fsck_get_num_dirinfo(e2fsck_t ctx)
{
      return ctx->dir_info ? ctx->dir_info->count : 0;
}

extern struct dir_info_iter *e2fsck_dir_info_iter_begin(e2fsck_t ctx)
{
      struct dir_info_iter *iter;
      struct dir_info_db *db = ctx->dir_info;

      iter = e2fsck_allocate_memory(ctx, sizeof(struct dir_info_iter),
                              "dir_info iterator");
      memset(iter, 0, sizeof(iter));

      if (db->tdb)
            iter->tdb_iter = tdb_firstkey(db->tdb);

      return iter;
}

extern void e2fsck_dir_info_iter_end(e2fsck_t ctx EXT2FS_ATTR((unused)),
                             struct dir_info_iter *iter)
{
      if (iter->tdb_iter.dptr)
            free(iter->tdb_iter.dptr);
      ext2fs_free_mem(&iter);
}

/*
 * A simple interator function
 */
struct dir_info *e2fsck_dir_info_iter(e2fsck_t ctx, struct dir_info_iter *iter)
{
      TDB_DATA data, key;
      struct dir_info_db *db = ctx->dir_info;
      struct dir_info_ent *buf;
      static struct dir_info ret_dir_info;

      if (!ctx->dir_info || !iter)
            return 0;

      if (db->tdb) {
            if (iter->tdb_iter.dptr == 0)
                  return 0;
            key = iter->tdb_iter;
            data = tdb_fetch(db->tdb, key);
            if (!data.dptr) {
                  printf("iter fetch failed: %s\n",
                         tdb_errorstr(db->tdb));
                  return 0;
            }
            buf = (struct dir_info_ent *) data.dptr;
            ret_dir_info.ino = *((ext2_ino_t *) iter->tdb_iter.dptr);
            ret_dir_info.dotdot = buf->dotdot;
            ret_dir_info.parent = buf->parent;
            iter->tdb_iter = tdb_nextkey(db->tdb, key);
            free(key.dptr);
            free(data.dptr);
            return &ret_dir_info;
      }

      if (iter->i >= ctx->dir_info->count)
            return 0;

#ifdef DIRINFO_DEBUG
      printf("iter(%d, %d, %d)...", ctx->dir_info->array[iter->i].ino,
             ctx->dir_info->array[iter->i].dotdot,
             ctx->dir_info->array[iter->i].parent);
#endif
      ctx->dir_info->last_lookup = ctx->dir_info->array + iter->i++;
      return(ctx->dir_info->last_lookup);
}

/*
 * This function only sets the parent pointer, and requires that
 * dirinfo structure has already been created.
 */
int e2fsck_dir_info_set_parent(e2fsck_t ctx, ext2_ino_t ino,
                         ext2_ino_t parent)
{
      struct dir_info *p;

      p = e2fsck_get_dir_info(ctx, ino);
      if (!p)
            return 1;
      p->parent = parent;
      e2fsck_put_dir_info(ctx, p);
      return 0;
}

/*
 * This function only sets the dot dot pointer, and requires that
 * dirinfo structure has already been created.
 */
int e2fsck_dir_info_set_dotdot(e2fsck_t ctx, ext2_ino_t ino,
                         ext2_ino_t dotdot)
{
      struct dir_info *p;

      p = e2fsck_get_dir_info(ctx, ino);
      if (!p)
            return 1;
      p->dotdot = dotdot;
      e2fsck_put_dir_info(ctx, p);
      return 0;
}

/*
 * This function only sets the parent pointer, and requires that
 * dirinfo structure has already been created.
 */
int e2fsck_dir_info_get_parent(e2fsck_t ctx, ext2_ino_t ino,
                         ext2_ino_t *parent)
{
      struct dir_info *p;

      p = e2fsck_get_dir_info(ctx, ino);
      if (!p)
            return 1;
      *parent = p->parent;
      return 0;
}

/*
 * This function only sets the dot dot pointer, and requires that
 * dirinfo structure has already been created.
 */
int e2fsck_dir_info_get_dotdot(e2fsck_t ctx, ext2_ino_t ino,
                         ext2_ino_t *dotdot)
{
      struct dir_info *p;

      p = e2fsck_get_dir_info(ctx, ino);
      if (!p)
            return 1;
      *dotdot = p->dotdot;
      return 0;
}


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