stc/libadacl.c: use a "cleanup" routine in acl_update_entry().

[apply-default-acl.git] / src / libadacl.c

diff --git a/src/libadacl.c b/src/libadacl.c
index cdd07fcfee7c7400256e9ea619cc6abea99a195d..5bca89fe405dc1a030bdab0ef4ccd55b8d5eab71 100644 (file)
--- a/src/libadacl.c
+++ b/src/libadacl.c
@@ -259,39 +259,47 @@ int acl_update_entry(acl_t aclp, acl_entry_t entry) {
     return ACL_ERROR;
   }
 
+  /* Our return value. Default to failure, and change to success if we
+     actually update something. */
+  int result = ACL_FAILURE;
+
   acl_entry_t existing_entry;
   /* Loop through the given ACL looking for matching entries. */
-  int result = acl_get_entry(aclp, ACL_FIRST_ENTRY, &existing_entry);
+  int get_entry_result = acl_get_entry(aclp, ACL_FIRST_ENTRY, &existing_entry);
 
-  while (result == ACL_SUCCESS) {
+  while (get_entry_result == ACL_SUCCESS) {
     acl_tag_t existing_tag = ACL_UNDEFINED_TAG;
 
     if (acl_get_tag_type(existing_entry, &existing_tag) == ACL_ERROR) {
        perror("set_acl_tag_permset (acl_get_tag_type)");
-       return ACL_ERROR;
+       result = ACL_ERROR;
+       goto cleanup;
     }
 
     if (existing_tag == entry_tag) {
       /* If we update something, we're done and return ACL_SUCCESS */
       if (acl_set_permset(existing_entry, entry_permset) == ACL_ERROR) {
-        perror("acl_update_entry (acl_set_permset)");
-        return ACL_ERROR;
+       perror("acl_update_entry (acl_set_permset)");
+       result = ACL_ERROR;
+       goto cleanup;
       }
 
-      return ACL_SUCCESS;
+      result = ACL_SUCCESS;
+      goto cleanup;
     }
 
-    result = acl_get_entry(aclp, ACL_NEXT_ENTRY, &existing_entry);
+    get_entry_result = acl_get_entry(aclp, ACL_NEXT_ENTRY, &existing_entry);
   }
 
   /* This catches both the initial acl_get_entry and the ones at the
      end of the loop. */
-  if (result == ACL_ERROR) {
+  if (get_entry_result == ACL_ERROR) {
     perror("acl_update_entry (acl_get_entry)");
-    return ACL_ERROR;
+    result = ACL_ERROR;
   }
 
-  return ACL_FAILURE;
+ cleanup:
+  return result;
 }
 
 
@@ -1003,7 +1011,30 @@ int apply_default_acl(const char* path, bool recursive) {
     return ACL_ERROR;
   }
   char* parent = dirname(dirname_path_copy);
+
+  basename_path_copy = strdup(path);
+  if (basename_path_copy == NULL) {
+    perror("apply_default_acl (strdup)");
+    result = ACL_ERROR;
+    goto cleanup;
+  }
+  char* child = basename(basename_path_copy);
+
+  /* Just kidding, if the path is "." or "..", then dirname will do
+   * the wrong thing and give us "." as its parent, too. So, we handle
+   * those as special cases. We use "child" instead of "path" here to
+   * catch things like "./" and "../"
+   */
+  bool path_is_dots = strcmp(child, ".") == 0 || strcmp(child, "..") == 0;
+  char dots_parent[6] = "../";
+  if (path_is_dots) {
+    /* We know that "child" contains no more than two characters here, and
+       using strncat to enforce that belief keeps clang-tidy happy. */
+    parent = strncat(dots_parent, child, 2);
+  }
+
   parent_fd = safe_open(parent, O_DIRECTORY | O_NOFOLLOW);
+
   if (parent_fd == OPEN_ERROR) {
     if (errno == ELOOP || errno == ENOTDIR) {
       /* We hit a symlink, either in the last path component (ELOOP)
@@ -1019,15 +1050,20 @@ int apply_default_acl(const char* path, bool recursive) {
   }
 
   /* We already obtained the parent fd safely, so if we use the
-     basename of path here instead of the full thing, then we can get
-     away with using openat() and spare ourselves the slowness of
-     another safe_open(). */
-  basename_path_copy = strdup(path);
-  if (basename_path_copy == NULL) {
-    perror("apply_default_acl (strdup)");
-    return ACL_ERROR;
+   * basename of path here instead of the full thing, then we can get
+   * away with using openat() and spare ourselves the slowness of
+   * another safe_open().
+   *
+   * Note that if the basename is "." or "..", then we don't want to
+   * open it relative to the parent_fd, so we need another special
+   * case for those paths here.
+   */
+  if (path_is_dots) {
+    fd = open(child, O_NOFOLLOW);
+  }
+  else {
+    fd = openat(parent_fd, child, O_NOFOLLOW);
   }
-  fd = openat(parent_fd, basename(basename_path_copy), O_NOFOLLOW);
   if (fd == OPEN_ERROR) {
     if (errno == ELOOP || errno == ENOTDIR) {
       /* We hit a symlink, either in the last path component (ELOOP)