Add mdb_copy for backing up a DB environment

[openldap] / libraries / libmdb / mdb.c

diff --git a/libraries/libmdb/mdb.c b/libraries/libmdb/mdb.c
index 262919a24c8bf2b63b3be7aa1c846bda1597fffe..7d9ea5cd4a4edad68bf592742ec26d0d28e72b6b 100644 (file)
--- a/libraries/libmdb/mdb.c
+++ b/libraries/libmdb/mdb.c
@@ -32,6 +32,7 @@
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
+#define _GNU_SOURCE
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/param.h>
@@ -3280,6 +3281,101 @@ mdb_env_close0(MDB_env *env, int excl)
        env->me_lfd = INVALID_HANDLE_VALUE;     /* Mark env as reset */
 }
 
+int
+mdb_env_copy(MDB_env *env, const char *path)
+{
+       MDB_txn *txn = NULL;
+       int rc, len, oflags;
+       size_t wsize;
+       char *lpath, *ptr;
+       HANDLE newfd = INVALID_HANDLE_VALUE;
+
+       if (env->me_flags & MDB_NOSUBDIR) {
+               lpath = path;
+       } else {
+               len = strlen(path);
+               len += sizeof(DATANAME);
+               lpath = malloc(len);
+               if (!lpath)
+                       return ENOMEM;
+               sprintf(lpath, "%s" DATANAME, path);
+       }
+
+       /* The destination path must exist, but the destination file must not.
+        * We don't want the OS to cache the writes, since the source data is
+        * already in the OS cache.
+        */
+#ifdef _WIN32
+       newfd = CreateFile(lpath, GENERIC_WRITE, 0, NULL, CREATE_NEW,
+                               FILE_FLAG_NO_BUFFERING|FILE_FLAG_WRITE_THROUGH, NULL);
+#else
+       newfd = open(lpath, O_WRONLY|O_CREAT|O_EXCL
+#ifdef O_DIRECT
+               |O_DIRECT
+#endif
+               , 0666);
+#endif
+       if (!(env->me_flags & MDB_NOSUBDIR))
+               free(lpath);
+       if (newfd == INVALID_HANDLE_VALUE) {
+               rc = ErrCode();
+               goto leave;
+       }
+
+#ifdef F_NOCACHE       /* __APPLE__ */
+       rc = fcntl(newfd, F_NOCACHE, 1);
+       if (rc) {
+               rc = ErrCode();
+               goto leave;
+       }
+#endif
+
+       /* Temporarily block writers until we snapshot the meta pages */
+       LOCK_MUTEX_W(env);
+
+       rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
+       if (rc) {
+               UNLOCK_MUTEX_W(env);
+               goto leave;
+       }
+
+       wsize = env->me_psize * 2;
+#ifdef _WIN32
+       {
+               DWORD len;
+               rc = WriteFile(newfd, env->me_map, wsize, &len, NULL);
+               rc = (len == wsize) ? MDB_SUCCESS : ErrCode();
+       }
+#else
+       rc = write(newfd, env->me_map, wsize);
+       rc = (rc == (int)wsize) ? MDB_SUCCESS : ErrCode();
+#endif
+       UNLOCK_MUTEX_W(env);
+
+       if (rc)
+               goto leave;
+
+       ptr = env->me_map + wsize;
+       wsize = txn->mt_next_pgno * env->me_psize - wsize;
+#ifdef _WIN32
+       {
+               DWORD len;
+               rc = WriteFile(newfd, ptr, wsize, &len, NULL);
+               rc = (len == wsize) ? MDB_SUCCESS : ErrCode();
+       }
+#else
+       rc = write(newfd, ptr, wsize);
+       rc = (rc == (int)wsize) ? MDB_SUCCESS : ErrCode();
+#endif
+       mdb_txn_abort(txn);
+
+leave:
+       if (newfd != INVALID_HANDLE_VALUE)
+               close(newfd);
+
+       return rc;
+}
+
 void
 mdb_env_close(MDB_env *env)
 {