From a93f22e050e3bc971f341ab4580d39266713133b Mon Sep 17 00:00:00 2001
From: Ralph Ronnquist <ralph.ronnquist@gmail.com>
Date: Thu, 11 Nov 2021 19:07:24 +1100
Subject: [PATCH] rework sanitized_source_directory using realpath

---
 fuse_xattrs.c | 42 ++++++++----------------------------------
 1 file changed, 8 insertions(+), 34 deletions(-)

diff --git a/fuse_xattrs.c b/fuse_xattrs.c
index 01d4d26..3539c65 100644
--- a/fuse_xattrs.c
+++ b/fuse_xattrs.c
@@ -194,45 +194,20 @@ static struct fuse_operations xmp_oper = {
 
 /**
  * Check if the path is valid. If it's a relative path,
- * prepend the working path.
+ * prepend the working path. Ensure it ends with /
  * @param path relative or absolute path to eval.
  * @return new string with absolute path
  */
 const char *sanitized_source_directory(const char *path) {
-    char *absolute_path;
-    if (strlen(path) == 0) {
-        return NULL;
+    char *absolute_path = stralloc( PATH_MAX );
+    if ( ( strlen( path ) == 0 ) ||
+	 ( realpath( path, absolute_path ) == 0 ) ||
+	 ( is_directory( absolute_path ) == -1 ) ) {
+	return NULL; // Path badness
     }
 
-    /* absolute path, we don't do anything */
-    if (path[0] == '/') {
-        if (is_directory(path) == -1) {
-            return NULL;
-        }
-        absolute_path = strdup(path);
-        return absolute_path;
-    }
-
-    static char cwd[MAXPATHLEN];
-    char *pwd = getcwd(cwd, sizeof(cwd));
-    size_t len = strlen(pwd) + 1 + strlen(path) + 1;
-    int has_trailing_backslash = (path[strlen(path)-1] == '/');
-    if (!has_trailing_backslash)
-        len++;
-
-    absolute_path = (char*) malloc(sizeof(char) * len);
-    memset(absolute_path, '\0', len);
-    sprintf(absolute_path, "%s/%s", pwd, path);
-
-    if(!has_trailing_backslash)
-        absolute_path[len-2] = '/';
-
-    if (is_directory(absolute_path) == -1) {
-        strfree(absolute_path);
-        return NULL;
-    }
-
-    return absolute_path;
+    // Append "/" and allocate new memory for the string
+    return strdup( strcat( absolute_path, "/" ) );
 }
 
 enum {
@@ -304,7 +279,6 @@ int main(int argc, char *argv[]) {
     if ( xattrs_config.sidecar_dir ) {
 	xattrs_config.sidecar_dir =
 	    sanitized_source_directory( xattrs_config.sidecar_dir );
-	return 0;
     }
     
     if (!xattrs_config.source_dir) {
-- 
2.39.2