use openat() when the parent dir is avaialable

Author: bertschinger

include/bf.h

@@ -325,20 +325,6 @@ typedef enum {
    CLOSE_DB  = 0x04,
 } CleanUpTasks;
 
-/*
- * A reference-counted directory handle.
- */
-struct dir_rc {
-   DIR *dir;
-   uint64_t rc;
-};
-
-struct dir_rc *open_dir_rc(int optional_fd, char *path);
-int get_dir_fd(struct dir_rc *dir);
-void dir_inc(struct dir_rc *dir);
-struct dir_rc *dir_clone(struct dir_rc *dir);
-void dir_dec(struct dir_rc *dir);
-
 /*
  * Minimum data needs to be passed around between threads.
  *
@@ -376,6 +362,20 @@ struct work *new_work_with_name(const char *prefix, const size_t prefix_len,
                                 const char *basename, const size_t basename_len);
 void free_work(struct work *w);
 
+/*
+ * A reference-counted directory handle.
+ */
+struct dir_rc {
+   DIR *dir;
+   uint64_t rc;
+};
+
+struct dir_rc *open_dir_rc(struct work *w);
+int get_dir_fd(struct dir_rc *dir);
+void dir_inc(struct dir_rc *dir);
+struct dir_rc *dir_clone(struct dir_rc *dir);
+void dir_dec(struct dir_rc *dir);
+
 /* extra data used by entries that does not depend on data from other directories */
 struct entry_data {
    int           parent_fd;    /* holds an FD that can be used for fstatat(2), etc. */

src/bf.c

@@ -581,38 +581,43 @@ INSTALL_NUMBER(SIZE, size_t, "%zu")
 INSTALL_NUMBER(UINT64, uint64_t, "%" PRIu64)
 
 /*
- * Create a new reference-counted DIR object. If optional_fd is a valid FD, then
- * openat() the new DIR relative to that FD. Otherwise, just opendir() the path.
+ * Create a new reference-counted DIR object for the given `struct work`.
+ *
+ * If work->parent_dir is a non-NULL dir_rc, then openat() the new DIR relative to it.
+ *     This assumes that w->basename_len is correctly initialized!
+ *
+ * Otherwise, just opendir() the path.
  *
  * Increments the refcount on the new object.
  */
-struct dir_rc *open_dir_rc(int optional_fd, char *path) {
+struct dir_rc *open_dir_rc(struct work *w) {
     DIR *dir;
 
-    if (optional_fd < 0) {
-        dir = opendir(path);
-    } else {
-        // XXX: assuming path is relative to optional_fd here... is this the right way to go????
-        // or do I need to do something like basename(path) first?
-        int fd = openat(optional_fd, path, O_RDONLY|O_DIRECTORY);
+    if (w->parent_dir) {
+        int d_fd = get_dir_fd(w->parent_dir);
+        char *basename = w->name + w->name_len - w->basename_len;
+        int fd = openat(d_fd, basename, O_RDONLY|O_DIRECTORY);
         if (fd < 0) {
             return NULL;
         }
         dir = fdopendir(fd);
+    } else {
+        dir = opendir(w->name);
     }
 
     if (!dir) {
         return NULL;
     }
 
     struct dir_rc *new = calloc(1, sizeof(*new));
+    // printf("creating dir at %p\n", new);
     new->dir = dir;
     dir_inc(new);
     return new;
 }
 
 /*
- * Get a DIR * out of a dir_rc.
+ * Get a directory FD out of a dir_rc.
  */
 int get_dir_fd(struct dir_rc *dir) {
     return gufi_dirfd(dir->dir);
@@ -622,6 +627,7 @@ int get_dir_fd(struct dir_rc *dir) {
  * Increment the reference count for a dir_rc.
  */
 void dir_inc(struct dir_rc *dir) {
+    // printf("incrementing dir at %p\n", dir);
     // XXX: is relaxed OK here?
     __atomic_fetch_add(&dir->rc, 1, __ATOMIC_ACQ_REL);
 }
@@ -640,7 +646,9 @@ struct dir_rc *dir_clone(struct dir_rc *dir) {
  */
 void dir_dec(struct dir_rc *dir) {
     if (dir) {
+        // printf("decrementing dir at %p\n", dir);
         if (__atomic_sub_fetch(&dir->rc, 1, __ATOMIC_ACQ_REL) == 0) {
+            // printf("freeing dir at %p\n", dir);
             closedir(dir->dir);
             free(dir);
         }

src/gufi_dir2index.c

@@ -203,7 +203,7 @@ static int processdir(QPTPool_t *ctx, const size_t id, void *data, void *args) {
         goto cleanup;
     }
 
-    struct dir_rc *dir_rc = open_dir_rc(-1, nda.work->name);
+    struct dir_rc *dir_rc = open_dir_rc(nda.work);
     if (!dir_rc) {
         const int err = errno;
         fprintf(stderr, "Error: Could not open directory \"%s\": %s (%d)\n", nda.work->name, strerror(err), err);

src/gufi_dir2trace.c

@@ -136,7 +136,7 @@ static int processdir(QPTPool_t *ctx, const size_t id, void *data, void *args) {
 
     decompress_work(&work, data);
 
-    struct dir_rc *dir_rc = open_dir_rc(-1, work->name);
+    struct dir_rc *dir_rc = open_dir_rc(work);
     if (!dir_rc) {
         rc = 1;
         goto cleanup;

src/gufi_index2dir.c

@@ -265,7 +265,7 @@ static int processdir(struct QPTPool * ctx, const size_t id, void * data, void *
     sqlite3 *db = NULL;
     int rc = 0;
 
-    struct dir_rc *dir_rc = open_dir_rc(-1, work->name);
+    struct dir_rc *dir_rc = open_dir_rc(work);
     if (!dir_rc) {
         fprintf(stderr, "Could not open directory \"%s\"\n", work->name);
         rc = 1;

src/gufi_treesummary.c

@@ -134,7 +134,7 @@ static int processdir(QPTPool_t *ctx, const size_t id, void *data, void *args) {
         goto out_free;
     }
 
-    struct dir_rc *dir_rc = open_dir_rc(-1, passmywork->name);
+    struct dir_rc *dir_rc = open_dir_rc(passmywork);
     if (!dir_rc) {
         goto out_free;
     }

src/parallel_cpr.c

@@ -231,7 +231,7 @@ static int cpr_dir(QPTPool_t *ctx, const size_t id, void *data, void *args) {
 
     int rc = 0;
 
-    struct dir_rc *dir_rc = open_dir_rc(-1, work->name);
+    struct dir_rc *dir_rc = open_dir_rc(work);
     if (!dir_rc) {
         print_error_and_goto("Could not open_directory", work->name, cleanup);
     }

test/unit/googletest/descend.cpp.in

@@ -93,7 +93,7 @@ TEST(descend, builddir) {
     const char root[] = "@CMAKE_BINARY_DIR@";
     struct work *work = new_work_with_name(nullptr, 0, root, strlen(root));
 
-    struct dir_rc *dir_rc = open_dir_rc(-1, work->name);
+    struct dir_rc *dir_rc = open_dir_rc(work);
     ASSERT_NE(dir_rc, nullptr);
     DIR *dir = dir_rc->dir;
 
@@ -249,7 +249,7 @@ TEST(descend, swap) {
     // descend to swap
     struct work *work = new_work_with_name(nullptr, 0, root, strlen(root));
 
-    struct dir_rc *dir_rc = open_dir_rc(-1, work->name);
+    struct dir_rc *dir_rc = open_dir_rc(work);
     ASSERT_NE(dir_rc, nullptr);
     DIR *dir = dir_rc->dir;