chase: CHASE_MKDIR_0755 requires CHASE_NONEXISTENT and/or CHASE_PARENT

When CHASE_MKDIR_0755 is specified without CHASE_NONEXISTENT and
CHASE_PARENT, then chase() succeeds only when the file specified by
the path already exists, and in that case, chase() does not create
any parent directories, and CHASE_MKDIR_0755 is meaningless.

Let's mention that CHASE_MKDIR_0755 needs to be specified with
CHASE_NONEXISTENT or CHASE_PARENT, and adds a assertion about that.

diff --git a/src/basic/chase.c b/src/basic/chase.c
index f167a439adff3a37239d8162798dab4d1eb0dd4b..eb4bda07a6f99d2e6e4290de5d36aabf26a07b8a 100644 (file)
--- a/src/basic/chase.c
+++ b/src/basic/chase.c
@@ -85,6 +85,7 @@ int chaseat(int dir_fd, const char *path, ChaseFlags flags, char **ret_path, int
         assert(!FLAGS_SET(flags, CHASE_PREFIX_ROOT));
         assert(!FLAGS_SET(flags, CHASE_STEP|CHASE_EXTRACT_FILENAME));
         assert(!FLAGS_SET(flags, CHASE_TRAIL_SLASH|CHASE_EXTRACT_FILENAME));
+        assert(!FLAGS_SET(flags, CHASE_MKDIR_0755) || (flags & (CHASE_NONEXISTENT | CHASE_PARENT)) != 0);
         assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
 
         /* Either the file may be missing, or we return an fd to the final object, but both make no sense */

diff --git a/src/basic/chase.h b/src/basic/chase.h
index 7e9ebe0685de92d528d503def3f7a62642d264cd..40121f7d70c7483082b9d51e9e2c01b0db42d7c3 100644 (file)
--- a/src/basic/chase.h
+++ b/src/basic/chase.h
@@ -24,8 +24,14 @@ typedef enum ChaseFlags {
                                              * full path is still stored in ret_path and only the returned
                                              * file descriptor will point to the parent directory. Note that
                                              * the result path is the root or '.', then the file descriptor
-                                             * also points to the result path even if this flag is set. */
-        CHASE_MKDIR_0755         = 1 << 11, /* Create any missing parent directories in the given path. */
+                                             * also points to the result path even if this flag is set.
+                                             * When this specified, chase() will succeed with 1 even if the
+                                             * file points to the last path component does not exist. */
+        CHASE_MKDIR_0755         = 1 << 11, /* Create any missing parent directories in the given path. This
+                                             * needs to be set with CHASE_NONEXISTENT and/or CHASE_PARENT.
+                                             * Note, chase_and_open() or friends always add CHASE_PARENT flag
+                                             * when internally call chase(), hence CHASE_MKDIR_0755 can be
+                                             * safely set without CHASE_NONEXISTENT and CHASE_PARENT. */
         CHASE_EXTRACT_FILENAME   = 1 << 12, /* Only return the last component of the resolved path */
 } ChaseFlags;
 

diff --git a/src/test/test-chase.c b/src/test/test-chase.c
index dee781929d9ada5e50e4102fa0ffc60c1689a249..1e98f5c6ed29e4960dd17b2b86bdbdc56f56b945 100644 (file)
--- a/src/test/test-chase.c
+++ b/src/test/test-chase.c
@@ -509,7 +509,7 @@ TEST(chaseat) {
         assert_se(streq(result, "q"));
         result = mfree(result);
 
-        assert_se(chaseat(tfd, "i/../p", CHASE_MKDIR_0755, NULL, NULL) == -ENOENT);
+        assert_se(chaseat(tfd, "i/../p", CHASE_MKDIR_0755|CHASE_NONEXISTENT, NULL, NULL) == -ENOENT);
 
         /* Test CHASE_FILENAME */