From: Stefan Metzmacher <metze@samba.org>
Date: Fri, 18 Jun 2021 13:31:58 +0000 (+0000)
Subject: vfs_preopen: completely reset the queue if the name structure changes
X-Git-Tag: tevent-0.11.0~98
X-Git-Url: http://git.samba.org/?a=commitdiff_plain;h=0900ab40d6de6b6d878b6a48cb3df464d536d91b;p=samba.git

vfs_preopen: completely reset the queue if the name structure changes

There's no point in trying to check if the current number is part
of the existing queue. This makes the logic at least more unstandable
to me.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>
---

diff --git a/source3/modules/vfs_preopen.c b/source3/modules/vfs_preopen.c
index 5640c30d666..f9f20ea6dc5 100644
--- a/source3/modules/vfs_preopen.c
+++ b/source3/modules/vfs_preopen.c
@@ -60,6 +60,7 @@ struct preopen_state {
 				 */
 
 	struct samba_path_matching *preopen_names;
+	ssize_t last_match_idx; /* remember the last match */
 };
 
 static void preopen_helper_destroy(struct preopen_helper *c)
@@ -342,6 +343,7 @@ static struct preopen_state *preopen_state_get(vfs_handle_struct *handle)
 		TALLOC_FREE(state);
 		return NULL;
 	}
+	state->last_match_idx = -1;
 
 	if (!SMB_VFS_HANDLE_TEST_DATA(handle)) {
 		SMB_VFS_HANDLE_SET_DATA(handle, state, preopen_free_helpers,
@@ -407,7 +409,9 @@ static int preopen_openat(struct vfs_handle_struct *handle,
 	char *new_template = NULL;
 	size_t new_start = 0;
 	int new_digits = -1;
+	size_t new_end = 0;
 	ssize_t match_idx = -1;
+	bool need_reset = false;
 
 	DEBUG(10, ("preopen_open called on %s\n", smb_fname_str_dbg(smb_fname)));
 
@@ -477,6 +481,48 @@ static int preopen_openat(struct vfs_handle_struct *handle,
 		TALLOC_FREE(new_template);
 		return res;
 	}
+	new_end = new_start + new_digits;
+
+	if (state->last_match_idx != match_idx) {
+		/*
+		 * If a different pattern caused the match
+		 * we better reset the queue
+		 */
+		need_reset = true;
+	} else if (state->number_start != new_start) {
+		/*
+		 * If the digits started at a different possition
+		 * we better reset the queue
+		 */
+		need_reset = true;
+	} else if (state->num_digits != new_digits) {
+		/*
+		 * If number of digits changed
+		 * we better reset the queue
+		 */
+		need_reset = true;
+	} else if (strncmp(state->template_fname, new_template, new_start) != 0) {
+		/*
+		 * If name before the digits changed
+		 * we better reset the queue
+		 */
+		need_reset = true;
+	} else if (strcmp(state->template_fname + new_end, new_template + new_end) != 0) {
+		/*
+		 * If name after the digits changed
+		 * we better reset the queue
+		 */
+		need_reset = true;
+	}
+
+	if (need_reset) {
+		/*
+		 * Reset the queue
+		 */
+		state->fnum_sent = 0;
+		state->fnum_queue_end = 0;
+		state->last_match_idx = match_idx;
+	}
 
 	TALLOC_FREE(state->template_fname);
 	state->template_fname = new_template;