libsmb/smb_share_modes.c

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/*
   Samba share mode database library external interface library.
   Used by non-Samba products needing access to the Samba share mode db.
                                                                                                                                  
   Copyright (C) Jeremy Allison 2005 - 2006

   sharemodes_procid functions (C) Copyright (C) Volker Lendecke 2005

     ** NOTE! The following LGPL license applies to this module only.
     ** This does NOT imply that all of Samba is released
     ** under the LGPL
                                                                                                                                  
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
                                                                                                                                  
   This 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
   Lesser General Public License for more details.
                                                                                                                                  
   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "includes.h"
#include "smb_share_modes.h"

/* Database context handle. */
struct smbdb_ctx {
        TDB_CONTEXT *smb_tdb;
};

/* Remove the paranoid malloc checker. */
#ifdef malloc
#undef malloc
#endif

int smb_create_share_mode_entry_ex(struct smbdb_ctx *db_ctx, uint64_t dev,
                                uint64_t ino, const struct smb_share_mode_entry *new_entry,
                                const char *sharepath, const char *filename);

static BOOL sharemodes_procid_equal(const struct process_id *p1, const struct process_id *p2)
{
        return (p1->pid == p2->pid);
}

static pid_t sharemodes_procid_to_pid(const struct process_id *proc)
{
        return proc->pid;
}

/*
 * open/close sharemode database.
 */

struct smbdb_ctx *smb_share_mode_db_open(const char *db_path)
{
        struct smbdb_ctx *smb_db = (struct smbdb_ctx *)malloc(sizeof(struct smbdb_ctx));

        if (!smb_db) {
                return NULL;
        }

        memset(smb_db, '\0', sizeof(struct smbdb_ctx));

        smb_db->smb_tdb = tdb_open(db_path,
                                0, TDB_DEFAULT|TDB_CLEAR_IF_FIRST,
                                O_RDWR|O_CREAT,
                                0644);

        if (!smb_db->smb_tdb) {
                free(smb_db);
                return NULL;
        }

        /* Should check that this is the correct version.... */
        return smb_db;
}

/* key and data records in the tdb locking database */
struct locking_key {
        SMB_DEV_T dev;
        SMB_INO_T inode;
};

int smb_share_mode_db_close(struct smbdb_ctx *db_ctx)
{
        int ret = tdb_close(db_ctx->smb_tdb);
        free(db_ctx);
        return ret;
}

static TDB_DATA get_locking_key(uint64_t dev, uint64_t ino)
{
        static struct locking_key lk;
        TDB_DATA ld;

        memset(&lk, '\0', sizeof(struct locking_key));
        lk.dev = (SMB_DEV_T)dev;
        lk.inode = (SMB_INO_T)ino;
        ld.dptr = (char *)&lk;
        ld.dsize = sizeof(lk);
        return ld;
}

/*
 * lock/unlock entry in sharemode database.
 */

int smb_lock_share_mode_entry(struct smbdb_ctx *db_ctx,
                                uint64_t dev,
                                uint64_t ino)
{
        return tdb_chainlock(db_ctx->smb_tdb, get_locking_key(dev, ino));
}
                                                                                                                                  
int smb_unlock_share_mode_entry(struct smbdb_ctx *db_ctx,
                                uint64_t dev,
                                uint64_t ino)
{
        return tdb_chainunlock(db_ctx->smb_tdb, get_locking_key(dev, ino));
}

/*
 * Check if an external smb_share_mode_entry and an internal share_mode entry match.
 */

static int share_mode_entry_equal(const struct smb_share_mode_entry *e_entry,
                                const struct share_mode_entry *entry)
{
        return (sharemodes_procid_equal(&e_entry->pid, &entry->pid) &&
                e_entry->file_id == (uint32_t)entry->share_file_id &&
                e_entry->open_time.tv_sec == entry->time.tv_sec &&
                e_entry->open_time.tv_usec == entry->time.tv_usec &&
                e_entry->share_access == (uint32_t)entry->share_access &&
                e_entry->access_mask == (uint32_t)entry->access_mask &&
                e_entry->dev == (uint64_t)entry->dev && 
                e_entry->ino == (uint64_t)entry->inode);
}

/*
 * Create an internal Samba share_mode entry from an external smb_share_mode_entry.
 */

static void create_share_mode_entry(struct share_mode_entry *out,
                                const struct smb_share_mode_entry *in)
{
        memset(out, '\0', sizeof(struct share_mode_entry));

        out->pid = in->pid;
        out->share_file_id = (unsigned long)in->file_id;
        out->time.tv_sec = in->open_time.tv_sec;
        out->time.tv_usec = in->open_time.tv_usec;
        out->share_access = in->share_access;
        out->access_mask = in->access_mask;
        out->dev = (SMB_DEV_T)in->dev;
        out->inode = (SMB_INO_T)in->ino;
        out->uid = (uint32)geteuid();
        out->flags = 0;
}

/*
 * Return the current share mode list for an open file.
 * This uses similar (but simplified) logic to locking/locking.c
 */

int smb_get_share_mode_entries(struct smbdb_ctx *db_ctx,
                                uint64_t dev,
                                uint64_t ino,
                                struct smb_share_mode_entry **pp_list,
                                unsigned char *p_delete_on_close)
{
        TDB_DATA db_data;
        struct smb_share_mode_entry *list = NULL;
        int num_share_modes = 0;
        struct locking_data *ld = NULL; /* internal samba db state. */
        struct share_mode_entry *shares = NULL;
        size_t i;
        int list_num;

        *pp_list = NULL;
        *p_delete_on_close = 0;

        db_data = tdb_fetch(db_ctx->smb_tdb, get_locking_key(dev, ino));
        if (!db_data.dptr) {
                return 0;
        }

        ld = (struct locking_data *)db_data.dptr;
        num_share_modes = ld->u.s.num_share_mode_entries;

        if (!num_share_modes) {
                free(db_data.dptr);
                return 0;
        }

        list = (struct smb_share_mode_entry *)malloc(sizeof(struct smb_share_mode_entry)*num_share_modes);
        if (!list) {
                free(db_data.dptr);
                return -1;
        }

        memset(list, '\0', num_share_modes * sizeof(struct smb_share_mode_entry));

        shares = (struct share_mode_entry *)(db_data.dptr + sizeof(struct locking_data));

        list_num = 0;
        for (i = 0; i < num_share_modes; i++) {
                struct share_mode_entry *share = &shares[i];
                struct smb_share_mode_entry *sme = &list[list_num];
                struct process_id pid = share->pid;

                /* Check this process really exists. */
                if (kill(sharemodes_procid_to_pid(&pid), 0) == -1 && (errno == ESRCH)) {
                        continue; /* No longer exists. */
                }

                /* Ignore deferred open entries. */
                if (share->op_type == DEFERRED_OPEN_ENTRY) {
                        continue;
                }

                /* Copy into the external list. */
                sme->dev = (uint64_t)share->dev;
                sme->ino = (uint64_t)share->inode;
                sme->share_access = (uint32_t)share->share_access;
                sme->access_mask = (uint32_t)share->access_mask;
                sme->open_time.tv_sec = share->time.tv_sec;
                sme->open_time.tv_usec = share->time.tv_usec;
                sme->file_id = (uint32_t)share->share_file_id;
                sme->pid = share->pid;
                list_num++;
        }

        if (list_num == 0) {
                free(db_data.dptr);
                free(list);
                return 0;
        }

        *p_delete_on_close = ld->u.s.delete_on_close;
        *pp_list = list;
        free(db_data.dptr);
        return list_num;
}

/* 
 * Create an entry in the Samba share mode db.
 */

int smb_create_share_mode_entry_ex(struct smbdb_ctx *db_ctx,
                                uint64_t dev,
                                uint64_t ino,
                                const struct smb_share_mode_entry *new_entry,
                                const char *sharepath, /* Must be absolute utf8 path. */
                                const char *filename) /* Must be relative utf8 path. */
{
        TDB_DATA db_data;
        TDB_DATA locking_key =  get_locking_key(dev, ino);
        int orig_num_share_modes = 0;
        struct locking_data *ld = NULL; /* internal samba db state. */
        struct share_mode_entry *shares = NULL;
        char *new_data_p = NULL;
        size_t new_data_size = 0;

        db_data = tdb_fetch(db_ctx->smb_tdb, locking_key);
        if (!db_data.dptr) {
                /* We must create the entry. */
                db_data.dptr = (char *)malloc(
                        sizeof(struct locking_data) +
                        sizeof(struct share_mode_entry) +
                        strlen(sharepath) + 1 +
                        strlen(filename) + 1);
                if (!db_data.dptr) {
                        return -1;
                }
                ld = (struct locking_data *)db_data.dptr;
                memset(ld, '\0', sizeof(struct locking_data));
                ld->u.s.num_share_mode_entries = 1;
                ld->u.s.delete_on_close = 0;
                ld->u.s.delete_token_size = 0;
                shares = (struct share_mode_entry *)(db_data.dptr + sizeof(struct locking_data));
                create_share_mode_entry(shares, new_entry);

                memcpy(db_data.dptr + sizeof(struct locking_data) + sizeof(struct share_mode_entry),
                        sharepath,
                        strlen(sharepath) + 1);
                memcpy(db_data.dptr + sizeof(struct locking_data) + sizeof(struct share_mode_entry) +
                        strlen(sharepath) + 1,
                        filename,
                        strlen(filename) + 1);

                db_data.dsize = sizeof(struct locking_data) + sizeof(struct share_mode_entry) +
                                        strlen(sharepath) + 1 +
                                        strlen(filename) + 1;
                if (tdb_store(db_ctx->smb_tdb, locking_key, db_data, TDB_INSERT) == -1) {
                        free(db_data.dptr);
                        return -1;
                }
                free(db_data.dptr);
                return 0;
        }

        /* Entry exists, we must add a new entry. */
        new_data_p = (char *)malloc(
                db_data.dsize + sizeof(struct share_mode_entry));
        if (!new_data_p) {
                free(db_data.dptr);
                return -1;
        }

        ld = (struct locking_data *)db_data.dptr;
        orig_num_share_modes = ld->u.s.num_share_mode_entries;

        /* Copy the original data. */
        memcpy(new_data_p, db_data.dptr, sizeof(struct locking_data) + (orig_num_share_modes * sizeof(struct share_mode_entry)));

        /* Add in the new share mode */
        shares = (struct share_mode_entry *)(new_data_p + sizeof(struct locking_data) +
                        (orig_num_share_modes * sizeof(struct share_mode_entry)));

        create_share_mode_entry(shares, new_entry);

        ld = (struct locking_data *)new_data_p;
        ld->u.s.num_share_mode_entries++;

        /* Append the original delete_token and filenames. */
        memcpy(new_data_p + sizeof(struct locking_data) + (ld->u.s.num_share_mode_entries * sizeof(struct share_mode_entry)),
                db_data.dptr + sizeof(struct locking_data) + (orig_num_share_modes * sizeof(struct share_mode_entry)),
                db_data.dsize - sizeof(struct locking_data) - (orig_num_share_modes * sizeof(struct share_mode_entry)));

        new_data_size = db_data.dsize + sizeof(struct share_mode_entry);

        free(db_data.dptr);

        db_data.dptr = new_data_p;
        db_data.dsize = new_data_size;

        if (tdb_store(db_ctx->smb_tdb, locking_key, db_data, TDB_REPLACE) == -1) {
                free(db_data.dptr);
                return -1;
        }
        free(db_data.dptr);
        return 0;
}

/* 
 * Create an entry in the Samba share mode db. Original interface - doesn't
 * Distinguish between share path and filename. Fudge this by using a
 * sharepath of / and a relative filename of (filename+1).
 */

int smb_create_share_mode_entry(struct smbdb_ctx *db_ctx,
                                uint64_t dev,
                                uint64_t ino,
                                const struct smb_share_mode_entry *new_entry,
                                const char *filename) /* Must be absolute utf8 path. */
{
        if (*filename != '/') {
                abort();
        }
        return smb_create_share_mode_entry_ex(db_ctx, dev, ino, new_entry,
                                                "/", &filename[1]);
}

int smb_delete_share_mode_entry(struct smbdb_ctx *db_ctx,
                                uint64_t dev,
                                uint64_t ino,
                                const struct smb_share_mode_entry *del_entry)
{
        TDB_DATA db_data;
        TDB_DATA locking_key =  get_locking_key(dev, ino);
        int orig_num_share_modes = 0;
        struct locking_data *ld = NULL; /* internal samba db state. */
        struct share_mode_entry *shares = NULL;
        char *new_data_p = NULL;
        size_t remaining_size = 0;
        size_t i, num_share_modes;
        const char *remaining_ptr = NULL;

        db_data = tdb_fetch(db_ctx->smb_tdb, locking_key);
        if (!db_data.dptr) {
                return -1; /* Error - missing entry ! */
        }

        ld = (struct locking_data *)db_data.dptr;
        orig_num_share_modes = ld->u.s.num_share_mode_entries;
        shares = (struct share_mode_entry *)(db_data.dptr + sizeof(struct locking_data));

        if (orig_num_share_modes == 1) {
                /* Only one entry - better be ours... */
                if (!share_mode_entry_equal(del_entry, shares)) {
                        /* Error ! We can't delete someone else's entry ! */
                        free(db_data.dptr);
                        return -1;
                }
                /* It's ours - just remove the entire record. */
                free(db_data.dptr);
                return tdb_delete(db_ctx->smb_tdb, locking_key);
        }

        /* More than one - allocate a new record minus the one we'll delete. */
        new_data_p = (char *)malloc(
                db_data.dsize - sizeof(struct share_mode_entry));
        if (!new_data_p) {
                free(db_data.dptr);
                return -1;
        }

        /* Copy the header. */
        memcpy(new_data_p, db_data.dptr, sizeof(struct locking_data));

        num_share_modes = 0;
        for (i = 0; i < orig_num_share_modes; i++) {
                struct share_mode_entry *share = &shares[i];
                struct process_id pid = share->pid;

                /* Check this process really exists. */
                if (kill(sharemodes_procid_to_pid(&pid), 0) == -1 && (errno == ESRCH)) {
                        continue; /* No longer exists. */
                }

                if (share_mode_entry_equal(del_entry, share)) {
                        continue; /* This is our delete taget. */
                }

                memcpy(new_data_p + sizeof(struct locking_data) +
                                (num_share_modes * sizeof(struct share_mode_entry)),
                        share, sizeof(struct share_mode_entry) );

                num_share_modes++;
        }

        if (num_share_modes == 0) {
                /* None left after pruning. Delete record. */
                free(db_data.dptr);
                free(new_data_p);
                return tdb_delete(db_ctx->smb_tdb, locking_key);
        }

        /* Copy any delete token plus the terminating filenames. */
        remaining_ptr = db_data.dptr + sizeof(struct locking_data) + (orig_num_share_modes * sizeof(struct share_mode_entry));
        remaining_size = db_data.dsize - (remaining_ptr - db_data.dptr);

        memcpy(new_data_p + sizeof(struct locking_data) + (num_share_modes * sizeof(struct share_mode_entry)),
                remaining_ptr,
                remaining_size);

        free(db_data.dptr);

        db_data.dptr = new_data_p;

        /* Re-save smaller record. */
        ld = (struct locking_data *)db_data.dptr;
        ld->u.s.num_share_mode_entries = num_share_modes;

        db_data.dsize = sizeof(struct locking_data) + (num_share_modes * sizeof(struct share_mode_entry)) + remaining_size;

        if (tdb_store(db_ctx->smb_tdb, locking_key, db_data, TDB_REPLACE) == -1) {
                free(db_data.dptr);
                return -1;
        }
        free(db_data.dptr);
        return 0;
}

int smb_change_share_mode_entry(struct smbdb_ctx *db_ctx,
                                uint64_t dev,
                                uint64_t ino,
                                const struct smb_share_mode_entry *set_entry,
                                const struct smb_share_mode_entry *new_entry)
{
        TDB_DATA db_data;
        TDB_DATA locking_key =  get_locking_key(dev, ino);
        int num_share_modes = 0;
        struct locking_data *ld = NULL; /* internal samba db state. */
        struct share_mode_entry *shares = NULL;
        size_t i;
        int found_entry = 0;

        db_data = tdb_fetch(db_ctx->smb_tdb, locking_key);
        if (!db_data.dptr) {
                return -1; /* Error - missing entry ! */
        }

        ld = (struct locking_data *)db_data.dptr;
        num_share_modes = ld->u.s.num_share_mode_entries;
        shares = (struct share_mode_entry *)(db_data.dptr + sizeof(struct locking_data));

        for (i = 0; i < num_share_modes; i++) {
                struct share_mode_entry *share = &shares[i];
                struct process_id pid = share->pid;

                /* Check this process really exists. */
                if (kill(sharemodes_procid_to_pid(&pid), 0) == -1 && (errno == ESRCH)) {
                        continue; /* No longer exists. */
                }

                if (share_mode_entry_equal(set_entry, share)) {
                        create_share_mode_entry(share, new_entry);
                        found_entry = 1;
                        break;
                }
        }

        if (!found_entry) {
                free(db_data.dptr);
                return -1;
        }

        /* Save modified data. */
        if (tdb_store(db_ctx->smb_tdb, locking_key, db_data, TDB_REPLACE) == -1) {
                free(db_data.dptr);
                return -1;
        }
        free(db_data.dptr);
        return 0;
}

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