From 0e98551307eb5a7a59cc74982b386dc95f4c4f89 Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=C3=A9r=C3=A9mie=20Galarneau?= Date: Thu, 23 Jan 2020 17:09:13 -0500 Subject: [PATCH] directory-handle: add an equals method MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Add an "equals" method to both implementations of directory-handle. The "directory fd" implementation uses the underlying inode of the directory to perform comparisons. Signed-off-by: Jérémie Galarneau Change-Id: I9c97f75ea6a79168d772268fca490aee7c333ae2 --- src/common/compat/directory-handle.c | 46 ++++++++++++++++++++++++++++ src/common/compat/directory-handle.h | 10 ++++++ 2 files changed, 56 insertions(+) diff --git a/src/common/compat/directory-handle.c b/src/common/compat/directory-handle.c index d9d1e2337..15ee5b5de 100644 --- a/src/common/compat/directory-handle.c +++ b/src/common/compat/directory-handle.c @@ -93,6 +93,26 @@ 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 +164,23 @@ 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); + } + } else { + handle->directory_inode = RESERVED_AT_FDCWD_INO; + } handle->dirfd = dirfd; urcu_ref_init(&handle->ref); end: @@ -199,6 +231,13 @@ 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) { @@ -550,6 +589,13 @@ 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->path, rhs->path) == 0; +} + static void lttng_directory_handle_invalidate(struct lttng_directory_handle *handle) { diff --git a/src/common/compat/directory-handle.h b/src/common/compat/directory-handle.h index 5974e36e3..0ad5c8510 100644 --- a/src/common/compat/directory-handle.h +++ b/src/common/compat/directory-handle.h @@ -37,6 +37,7 @@ enum lttng_directory_handle_rmdir_recursive_flags { #ifdef COMPAT_DIRFD struct lttng_directory_handle { struct urcu_ref ref; + ino_t directory_inode; int dirfd; }; @@ -256,4 +257,13 @@ int lttng_directory_handle_remove_subdirectory_recursive_as_user( const struct lttng_credentials *creds, int flags); +/* + * Compare two directory handles. + * + * Returns true if the two directory handles are equal, false otherwise. + */ +LTTNG_HIDDEN +bool lttng_directory_handle_equals(const struct lttng_directory_handle *lhs, + const struct lttng_directory_handle *rhs); + #endif /* _COMPAT_PATH_HANDLE_H */ -- 2.34.1