src/libadacl.c: rewrite acl_set_entry() as acl_update_entry().

It turns out we only need to update existing entries in our ACLs, to
mask the execute permissions. Since we never need to create new
entries, the name "acl_set_entry" was not quite right. The
new-entry-creation code has been removed from the bottom half of the
function, and it has been renamed to "acl_update_entry".

diff --git a/src/libadacl.c b/src/libadacl.c
index d99cb8f6bfbae32b86503c084d19c3f36061aae7..22f5d7b3ad900dbcc5f8bb9c01d90e62bb897a96 100644 (file)
--- a/src/libadacl.c
+++ b/src/libadacl.c
@@ -199,51 +199,41 @@ int safe_open(const char* pathname, int flags) {
 
 
 /**
- * @brief Update (or create) an entry in an @b minimal ACL.
- *
- * This function will not work if @c aclp contains extended
- * entries. This is fine for our purposes, since we call @c wipe_acls
- * on each path before applying the default to it.
- *
- * The assumption that there are no extended entries makes things much
- * simpler. For example, we only have to update the @c ACL_USER_OBJ,
- * @c ACL_GROUP_OBJ, and @c ACL_OTHER entries -- all others can simply
- * be created anew. This means we don't have to fool around comparing
- * named-user/group entries.
+ * @brief Update an entry in an @b minimal ACL.
  *
  * @param aclp
- *   A pointer to the acl_t structure whose entry we want to modify.
+ *   A pointer to the acl_t structure whose entry we want to update.
  *
  * @param entry
- *   The new entry. If @c entry contains a user/group/other entry, we
- *   update the existing one. Otherwise we create a new entry.
- *
- * @return If there is an unexpected library error, @c ACL_ERROR is
- *   returned. Otherwise, @c ACL_SUCCESS.
+ *   The new entry.
  *
+ * @return
+ *   - @c ACL_SUCCESS - If we update an existing entry.
+ *   - @c ACL_FAILURE - If we don't find an entry to update.
+ *   - @c ACL_ERROR - Unexpected library error.
  */
-int acl_set_entry(acl_t* aclp, acl_entry_t entry) {
+int acl_update_entry(acl_t aclp, acl_entry_t entry) {
   if (aclp == NULL || entry == NULL) {
     errno = EINVAL;
-    perror("acl_set_entry (args)");
+    perror("acl_update_entry (args)");
     return ACL_ERROR;
   }
 
   acl_tag_t entry_tag;
   if (acl_get_tag_type(entry, &entry_tag) == ACL_ERROR) {
-    perror("acl_set_entry (acl_get_tag_type)");
+    perror("acl_update_entry (acl_get_tag_type)");
     return ACL_ERROR;
   }
 
   acl_permset_t entry_permset;
   if (acl_get_permset(entry, &entry_permset) == ACL_ERROR) {
-    perror("acl_set_entry (acl_get_permset)");
+    perror("acl_update_entry (acl_get_permset)");
     return ACL_ERROR;
   }
 
   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 result = acl_get_entry(aclp, ACL_FIRST_ENTRY, &existing_entry);
 
   while (result == ACL_SUCCESS) {
     acl_tag_t existing_tag = ACL_UNDEFINED_TAG;
@@ -256,64 +246,24 @@ int acl_set_entry(acl_t* aclp, acl_entry_t entry) {
     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_set_entry (acl_set_permset)");
+        perror("acl_update_entry (acl_set_permset)");
         return ACL_ERROR;
       }
 
       return ACL_SUCCESS;
     }
 
-    result = acl_get_entry(*aclp, ACL_NEXT_ENTRY, &existing_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) {
-    perror("acl_set_entry (acl_get_entry)");
-    return ACL_ERROR;
-  }
-
-  /* If we've made it this far, we need to add a new entry to the
-     ACL. */
-  acl_entry_t new_entry;
-
-  /* The acl_create_entry() function can allocate new memory and/or
-   * change the location of the ACL structure entirely. When that
-   * happens, the value pointed to by aclp is updated, which means
-   * that a new acl_t gets "passed out" to our caller, eventually to
-   * be fed to acl_free(). In other words, we should still be freeing
-   * the right thing, even if the value pointed to by aclp changes.
-   */
-  if (acl_create_entry(aclp, &new_entry) == ACL_ERROR) {
-    perror("acl_set_entry (acl_create_entry)");
-    return ACL_ERROR;
-  }
-
-  if (acl_set_tag_type(new_entry, entry_tag) == ACL_ERROR) {
-    perror("acl_set_entry (acl_set_tag_type)");
+    perror("acl_update_entry (acl_get_entry)");
     return ACL_ERROR;
   }
 
-  if (acl_set_permset(new_entry, entry_permset) == ACL_ERROR) {
-    perror("acl_set_entry (acl_set_permset)");
-    return ACL_ERROR;
-  }
-
-  if (entry_tag == ACL_USER || entry_tag == ACL_GROUP) {
-    /* We need to set the qualifier too. */
-    void* entry_qual = acl_get_qualifier(entry);
-    if (entry_qual == (void*)NULL) {
-      perror("acl_set_entry (acl_get_qualifier)");
-      return ACL_ERROR;
-    }
-
-    if (acl_set_qualifier(new_entry, entry_qual) == ACL_ERROR) {
-      perror("acl_set_entry (acl_set_qualifier)");
-      return ACL_ERROR;
-    }
-  }
-
-  return ACL_SUCCESS;
+  return ACL_FAILURE;
 }
 
 
@@ -917,25 +867,8 @@ int apply_default_acl_ex(const char* path,
       }
     }
 
-    /* Finally, add the permset to the access ACL. It's actually
-     * important that we pass in the address of "new_acl" here, and not
-     * "new_acl" itself. Why? The call to acl_create_entry() within
-     * acl_set_entry() can allocate new memory for the entry.
-     * Sometimes that can be done in-place, in which case everything
-     * is cool and the new memory gets released when we call
-     * acl_free(acl).
-     *
-     * But occasionally, the whole ACL structure will have to be moved
-     * in order to allocate the extra space. When that happens,
-     * acl_create_entry() modifies the pointer it was passed (in this
-     * case, &acl) to point to the new location. We want to call
-     * acl_free() on the new location, and since acl_free() gets
-     * called right here, we need acl_create_entry() to update the
-     * value of "new_acl". To do that, it needs the address of "new_acl".
-     */
-
-    if (acl_set_entry(&new_acl, entry) == ACL_ERROR) {
-      perror("apply_default_acl_ex (acl_set_entry)");
+    if (acl_update_entry(new_acl, entry) == ACL_ERROR) {
+      perror("apply_default_acl_ex (acl_update_entry)");
       result = ACL_ERROR;
       goto cleanup;
     }