source: branches/samba-3.2.x/source/modules/vfs_fileid.c@ 579

/*
 * VFS module to alter the algorithm to calculate
 * the struct file_id used as key for the share mode
 * and byte range locking db's.
 *
 * Copyright (C) 2007, Stefan Metzmacher
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

#include "includes.h"

static int vfs_fileid_debug_level = DBGC_VFS;

#undef DBGC_CLASS
#define DBGC_CLASS vfs_fileid_debug_level

struct fileid_mount_entry {
        SMB_DEV_T device;
        const char *mnt_fsname;
        fsid_t fsid;
        uint64_t devid;
};

struct fileid_handle_data {
        uint64_t (*device_mapping_fn)(struct fileid_handle_data *data,
                                      SMB_DEV_T dev);
        unsigned num_mount_entries;
        struct fileid_mount_entry *mount_entries;
};

/* load all the mount entries from the mtab */
static void fileid_load_mount_entries(struct fileid_handle_data *data)
{
        FILE *f;
        struct mntent *m;

        data->num_mount_entries = 0;
        TALLOC_FREE(data->mount_entries);

        f = setmntent("/etc/mtab", "r");
        if (!f) return;

        while ((m = getmntent(f))) {
                struct stat st;
                struct statfs sfs;
                struct fileid_mount_entry *cur;

                if (stat(m->mnt_dir, &st) != 0) continue;
                if (statfs(m->mnt_dir, &sfs) != 0) continue;

                if (strncmp(m->mnt_fsname, "/dev/", 5) == 0) {
                        m->mnt_fsname += 5;
                }

                data->mount_entries = TALLOC_REALLOC_ARRAY(data,
                                                           data->mount_entries,
                                                           struct fileid_mount_entry,
                                                           data->num_mount_entries+1);
                if (data->mount_entries == NULL) {
                        goto nomem;
                }

                cur = &data->mount_entries[data->num_mount_entries];
                cur->device     = st.st_dev;
                cur->mnt_fsname = talloc_strdup(data->mount_entries,
                                                m->mnt_fsname);
                if (!cur->mnt_fsname) goto nomem;
                cur->fsid       = sfs.f_fsid;
                cur->devid      = (uint64_t)-1;

                data->num_mount_entries++;
        }
        endmntent(f);
        return;
        
nomem:
        if (f) endmntent(f);

        data->num_mount_entries = 0;
        TALLOC_FREE(data->mount_entries);

        return;
}

/* find a mount entry given a dev_t */
static struct fileid_mount_entry *fileid_find_mount_entry(struct fileid_handle_data *data,
                                                          SMB_DEV_T dev)
{
        int i;

        if (data->num_mount_entries == 0) {
                fileid_load_mount_entries(data);
        }
        for (i=0;i<data->num_mount_entries;i++) {
                if (data->mount_entries[i].device == dev) {
                        return &data->mount_entries[i];
                }
        }
        /* 2nd pass after reloading */
        fileid_load_mount_entries(data);
        for (i=0;i<data->num_mount_entries;i++) {
                if (data->mount_entries[i].device == dev) {
                        return &data->mount_entries[i];
                }
        }       
        return NULL;
}