From: Michael Orlitzky <michael@orlitzky.com>
Date: Mon, 18 Jun 2018 01:28:32 +0000 (-0400)
Subject: src/libadacl.c: simplify the "." and ".." path handling.
X-Git-Tag: v0.4.1~4
X-Git-Url: https://gitweb.michael.orlitzky.com/?a=commitdiff_plain;h=cb2ef6b2386de44200124904c7a03ce8512f3585;p=apply-default-acl.git

src/libadacl.c: simplify the "." and ".." path handling.

The initial fix for the path arguments "." and ".." was a little
hacky, but necessary to get the test suite passing. Now the logic is a
little cleaner, and both paths are handled in one special-case rather
than two separate "if" statements.
---

diff --git a/src/libadacl.c b/src/libadacl.c
index 911e69a..8ff0c17 100644
--- a/src/libadacl.c
+++ b/src/libadacl.c
@@ -1004,24 +1004,18 @@ int apply_default_acl(const char* path, bool recursive) {
   }
   char* parent = dirname(dirname_path_copy);
 
-  /* Just kidding, if the path is ".", then dirname will do the wrong
-   * thing and give us "." as its parent, too. So, we handle that as a
-   * special case.
-   *
-   * WARNING: it is important that "parent" itself is not used after
-   * this point; otherwise we would need to store the correct parent
-   * path in there. But since everything uses file descriptors from
-   * now on, we only need to ensure that we get the correct parent_fd
-   * below. */
-  if (strcmp(path, ".") == 0 && strcmp(parent, ".") == 0) {
-    parent_fd = safe_open("..", O_DIRECTORY | O_NOFOLLOW);
-  }
-  else if (strcmp(path, "..") == 0 && strcmp(parent, ".") == 0) {
-    parent_fd = safe_open("../..", O_DIRECTORY | O_NOFOLLOW);
-  }
-  else {
-    parent_fd = safe_open(parent, O_DIRECTORY | O_NOFOLLOW);
+  /* 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.
+   */
+  bool path_is_dots = strcmp(path, ".") == 0 || strcmp(path, "..") == 0;
+  char dots_parent[6] = "../";
+  if (path_is_dots) {
+    parent = strcat(dots_parent, path);
   }
+
+  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)
@@ -1047,14 +1041,11 @@ int apply_default_acl(const char* path, bool recursive) {
     goto cleanup;
   }
 
-  /* If the basename is ".", then we don't want to open "." relative
-     to the parent_fd, so we need another special case for that
-     path. */
-  if (strcmp(path, ".") == 0 && strcmp(parent, ".") == 0) {
-    fd = open(".", O_NOFOLLOW);
-  }
-  else if (strcmp(path, "..") == 0 && strcmp(parent, ".") == 0) {
-    fd = open("..", O_NOFOLLOW);
+  /* 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. */
+  if (path_is_dots) {
+    fd = open(path, O_NOFOLLOW);
   }
   else {
     fd = openat(parent_fd, basename(basename_path_copy), O_NOFOLLOW);