support-findfirst-for-write-only-directories   [plain text]

PR-5243958 cannot copy into dropbox

The OS X client uses the findfirst call to get some file attributes,
but this code path depends on being able to open the containing
directory even though it might not be necessary.

In the specific case where we know we are searching for a filename
(not a wildcard), we now allow the directory open to fail. This
assumes that a subsequent stat will give us an authoritative result
(which is true for case-insensitive file systems).

This should be viewed as an interim fix to make dropboxes work. The
real fix involves tearing apart the whole findfirst code path so
we can propagate state and error correctly.

Index: samba/source/smbd/dir.c
===================================================================
--- samba/source/smbd/dir.c.orig
+++ samba/source/smbd/dir.c
@@ -160,10 +160,8 @@ static void dptr_idleoldest(void)
 	 */
 
 	for(; dptr; dptr = dptr->prev) {
-		if (dptr->dir_hnd) {
-			dptr_idle(dptr);
-			return;
-		}
+		dptr_idle(dptr);
+		return;
 	}
 }
 
@@ -318,8 +316,9 @@ void dptr_idlecnum(connection_struct *co
 {
 	struct dptr_struct *dptr;
 	for(dptr = dirptrs; dptr; dptr = dptr->next) {
-		if (dptr->conn == conn && dptr->dir_hnd)
+		if (dptr->conn == conn) {
 			dptr_idle(dptr);
+		}
 	}
 }
 
@@ -332,8 +331,9 @@ void dptr_closepath(char *path,uint16 sp
 	struct dptr_struct *dptr, *next;
 	for(dptr = dirptrs; dptr; dptr = next) {
 		next = dptr->next;
-		if (spid == dptr->spid && strequal(dptr->path,path))
+		if (spid == dptr->spid && strequal(dptr->path,path)) {
 			dptr_close_internal(dptr);
+		}
 	}
 }
 
@@ -643,6 +643,22 @@ const char *dptr_ReadDirName(struct dptr
 			return NULL;
 		}
 	}
+
+	/* We can get here if we were searching for a filename (not a wildcard)
+	 * but we weren't able to open the containing directory. We have no
+	 * hope of iterating, so we can only return NULL here.
+	 */
+	if (dptr->dir_hnd->dir == NULL) {
+		/* XXX What we should be doing here is saving the errno from
+		 * when we originally failed to open the directory. We need to
+		 * return an NT_STATUS at this point so we can faithfully tell
+		 * the client that we couldn't search for the file (distinct
+		 * from the file not being found).
+		 */
+		dptr->dir_hnd->offset = *poffset = END_OF_DIRECTORY_OFFSET;
+		return NULL;
+	}
+
 	return dptr_normal_ReadDirName(dptr, poffset, pst);
 }
 
@@ -1063,7 +1079,7 @@ BOOL is_visible_file(connection_struct *
  Open a directory.
 ********************************************************************/
 
-struct smb_Dir *OpenDir(connection_struct *conn, const char *name, const char *mask, uint32 attr)
+struct smb_Dir *OpenDir(connection_struct *conn, const char *path, const char *mask, uint32 attr)
 {
 	struct smb_Dir *dirp = SMB_MALLOC_P(struct smb_Dir);
 	if (!dirp) {
@@ -1073,14 +1089,30 @@ struct smb_Dir *OpenDir(connection_struc
 
 	dirp->conn = conn;
 
-	dirp->dir_path = SMB_STRDUP(name);
+	dirp->dir_path = SMB_STRDUP(path);
 	if (!dirp->dir_path) {
 		goto fail;
 	}
+
 	dirp->dir = SMB_VFS_OPENDIR(conn, dirp->dir_path, mask, attr);
 	if (!dirp->dir) {
-		DEBUG(5,("OpenDir: Can't open %s. %s\n", dirp->dir_path, strerror(errno) ));
-		goto fail;
+		/* Unless we will be doing a wildcard search, iterating over
+		 * the whole directory, or the path isn't a directory,
+		 * we can try to muddle on without a directory handle.
+		 */
+		if (errno == ENOENT || errno == ENOTDIR ||
+		    mask == NULL || ms_has_wild(mask)) {
+			DEBUG(5, ("OpenDir: can't open directory '%s': %s\n",
+				dirp->dir_path, strerror(errno) ));
+			goto fail;
+		}
+
+		/* We now have a directory handle that is not backed by an open
+		 * directory. The only valid operation is to close or to read
+		 * the (non-wildcard) name.
+		 */
+		DEBUG(5, ("OpenDir: can't open directory '%s': %s, continuing\n",
+			dirp->dir_path, strerror(errno) ));
 	}
 
 	dirp->name_cache = SMB_CALLOC_ARRAY(struct name_cache_entry, NAME_CACHE_SIZE);
@@ -1138,6 +1170,8 @@ const char *ReadDirName(struct smb_Dir *
 	const char *n;
 	connection_struct *conn = dirp->conn;
 
+	SMB_ASSERT(dirp->dir != NULL);
+
 	/* Cheat to allow . and .. to be the first entries returned. */
 	if (((*poffset == START_OF_DIRECTORY_OFFSET) || (*poffset == DOT_DOT_DIRECTORY_OFFSET)) && (dirp->file_number < 2)) {
 		if (dirp->file_number == 0) {
@@ -1178,7 +1212,10 @@ const char *ReadDirName(struct smb_Dir *
 
 void RewindDir(struct smb_Dir *dirp, long *poffset)
 {
+	SMB_ASSERT(dirp->dir != NULL);
+
 	SMB_VFS_REWINDDIR(dirp->conn, dirp->dir);
+
 	dirp->file_number = 0;
 	dirp->offset = START_OF_DIRECTORY_OFFSET;
 	*poffset = START_OF_DIRECTORY_OFFSET;
@@ -1190,6 +1227,7 @@ void RewindDir(struct smb_Dir *dirp, lon
 
 void SeekDir(struct smb_Dir *dirp, long offset)
 {
+	SMB_ASSERT(dirp->dir != NULL);
 	if (offset != dirp->offset) {
 		if (offset == START_OF_DIRECTORY_OFFSET) {
 			RewindDir(dirp, &offset);
@@ -1252,6 +1290,11 @@ BOOL SearchDir(struct smb_Dir *dirp, con
 	const char *entry;
 	connection_struct *conn = dirp->conn;
 
+	/* Search is only valid for wildcards and we must have an open
+	 * directory for those.
+	 */
+	SMB_ASSERT(dirp->dir != NULL);
+
 	/* Search back in the name cache. */
 	for (i = dirp->name_cache_index; i >= 0; i--) {
 		struct name_cache_entry *e = &dirp->name_cache[i];