directory-handle: print `errno` reason on `unlinkat()` error

[lttng-tools.git] / src / common / compat / directory-handle.c

diff --git a/src/common/compat/directory-handle.c b/src/common/compat/directory-handle.c
index d9d1e233757bdb76bbabdc51436ac13b02388574..aea4be5fe27ffc54e3c9c873fa36209317cb2ba9 100644 (file)
--- a/src/common/compat/directory-handle.c
+++ b/src/common/compat/directory-handle.c
@@ -1,18 +1,8 @@
 /*
- * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #include <common/compat/directory-handle.h>
@@ -36,9 +26,6 @@
  * of the internal API below.
  */
 static
-int lttng_directory_handle_stat(const struct lttng_directory_handle *handle,
-               const char *path, struct stat *st);
-static
 int lttng_directory_handle_mkdir(
                const struct lttng_directory_handle *handle,
                const char *path, mode_t mode);
@@ -93,6 +80,26 @@ void lttng_directory_handle_release(struct urcu_ref *ref);
 
 #ifdef COMPAT_DIRFD
 
+/*
+ * Special inode number reserved to represent the "current working directory".
+ * ino_t is spec'ed as being an unsigned integral type.
+ */
+#define RESERVED_AT_FDCWD_INO                      \
+       ({                                         \
+               uint64_t reserved_val;             \
+               switch (sizeof(ino_t)) {           \
+               case 4:                            \
+                       reserved_val = UINT32_MAX; \
+                       break;                     \
+               case 8:                            \
+                       reserved_val = UINT64_MAX; \
+                       break;                     \
+               default:                           \
+                       abort();                   \
+               }                                  \
+               (ino_t) reserved_val;              \
+       })
+
 LTTNG_HIDDEN
 struct lttng_directory_handle *lttng_directory_handle_create(const char *path)
 {
@@ -144,11 +151,25 @@ LTTNG_HIDDEN
 struct lttng_directory_handle *lttng_directory_handle_create_from_dirfd(
                int dirfd)
 {
+       int ret;
        struct lttng_directory_handle *handle = zmalloc(sizeof(*handle));
+       struct stat stat_buf;
 
        if (!handle) {
                goto end;
        }
+
+       if (dirfd != AT_FDCWD) {
+               ret = fstat(dirfd, &stat_buf);
+               if (ret) {
+                       PERROR("Failed to fstat directory file descriptor %i", dirfd);
+                       lttng_directory_handle_release(&handle->ref);
+                       handle = NULL;
+                       goto end;
+               }
+       } else {
+               handle->directory_inode = RESERVED_AT_FDCWD_INO;
+       }
        handle->dirfd = dirfd;
        urcu_ref_init(&handle->ref);
 end:
@@ -162,6 +183,10 @@ void lttng_directory_handle_release(struct urcu_ref *ref)
        struct lttng_directory_handle *handle =
                        container_of(ref, struct lttng_directory_handle, ref);
 
+       if (handle->destroy_cb) {
+               handle->destroy_cb(handle, handle->destroy_cb_data);
+       }
+
        if (handle->dirfd == AT_FDCWD || handle->dirfd == -1) {
                goto end;
        }
@@ -199,19 +224,33 @@ end:
        return new_handle;
 }
 
+LTTNG_HIDDEN
+bool lttng_directory_handle_equals(const struct lttng_directory_handle *lhs,
+               const struct lttng_directory_handle *rhs)
+{
+       return lhs->directory_inode == rhs->directory_inode;
+}
+
 static
 void lttng_directory_handle_invalidate(struct lttng_directory_handle *handle)
 {
        handle->dirfd = -1;
 }
 
-static
+LTTNG_HIDDEN
 int lttng_directory_handle_stat(const struct lttng_directory_handle *handle,
                const char *path, struct stat *st)
 {
        return fstatat(handle->dirfd, path, st, 0);
 }
 
+LTTNG_HIDDEN
+bool lttng_directory_handle_uses_fd(
+               const struct lttng_directory_handle *handle)
+{
+       return handle->dirfd != AT_FDCWD;
+}
+
 static
 int lttng_directory_handle_mkdir(
                const struct lttng_directory_handle *handle,
@@ -316,7 +355,12 @@ static
 int lttng_directory_handle_rmdir(
                const struct lttng_directory_handle *handle, const char *name)
 {
-       return unlinkat(handle->dirfd, name, AT_REMOVEDIR);
+       int ret = unlinkat(handle->dirfd, name, AT_REMOVEDIR);
+       if (ret) {
+               PERROR("Failed to remove directory `%s`", name);
+       }
+
+       return ret;
 }
 
 static
@@ -550,13 +594,20 @@ end:
        return new_handle;
 }
 
+LTTNG_HIDDEN
+bool lttng_directory_handle_equals(const struct lttng_directory_handle *lhs,
+               const struct lttng_directory_handle *rhs)
+{
+       return strcmp(lhs->base_path, rhs->base_path) == 0;
+}
+
 static
 void lttng_directory_handle_invalidate(struct lttng_directory_handle *handle)
 {
        handle->base_path = NULL;
 }
 
-static
+LTTNG_HIDDEN
 int lttng_directory_handle_stat(const struct lttng_directory_handle *handle,
                const char *subdirectory, struct stat *st)
 {
@@ -574,6 +625,13 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
+bool lttng_directory_handle_uses_fd(
+               const struct lttng_directory_handle *handle)
+{
+       return false;
+}
+
 static
 int lttng_directory_handle_mkdir(const struct lttng_directory_handle *handle,
                const char *subdirectory, mode_t mode)