diff options
| -rw-r--r-- | src/basic/fd-util.c | 27 | ||||
| -rw-r--r-- | src/basic/fd-util.h | 2 | ||||
| -rw-r--r-- | src/test/test-fs-util.c | 6 |
3 files changed, 23 insertions, 12 deletions
diff --git a/src/basic/fd-util.c b/src/basic/fd-util.c index 8ae79fb69..21c9d8b87 100644 --- a/src/basic/fd-util.c +++ b/src/basic/fd-util.c @@ -431,7 +431,6 @@ int move_fd(int from, int to, int cloexec) { int acquire_data_fd(const void *data, size_t size, unsigned flags) { - char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)]; _cleanup_close_pair_ int pipefds[2] = { -1, -1 }; char pattern[] = "/dev/shm/data-fd-XXXXXX"; _cleanup_close_ int fd = -1; @@ -541,12 +540,7 @@ try_dev_shm: return -EIO; /* Let's reopen the thing, in order to get an O_RDONLY fd for the original O_RDWR one */ - xsprintf(procfs_path, "/proc/self/fd/%i", fd); - r = open(procfs_path, O_RDONLY|O_CLOEXEC); - if (r < 0) - return -errno; - - return r; + return fd_reopen(fd, O_RDONLY|O_CLOEXEC); } try_dev_shm_without_o_tmpfile: @@ -729,3 +723,22 @@ finish: return r; } + +int fd_reopen(int fd, int flags) { + char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)]; + int new_fd; + + /* Reopens the specified fd with new flags. This is useful for convert an O_PATH fd into a regular one, or to + * turn O_RDWR fds into O_RDONLY fds. + * + * This doesn't work on sockets (since they cannot be open()ed, ever). + * + * This implicitly resets the file read index to 0. */ + + xsprintf(procfs_path, "/proc/self/fd/%i", fd); + new_fd = open(procfs_path, flags); + if (new_fd < 0) + return -errno; + + return new_fd; +} diff --git a/src/basic/fd-util.h b/src/basic/fd-util.h index cb4677ec4..0f5a950f1 100644 --- a/src/basic/fd-util.h +++ b/src/basic/fd-util.h @@ -117,3 +117,5 @@ static inline int make_null_stdio(void) { (fd) = -1; \ _fd_; \ }) + +int fd_reopen(int fd, int flags); diff --git a/src/test/test-fs-util.c b/src/test/test-fs-util.c index ba01eea4e..35bb699c3 100644 --- a/src/test/test-fs-util.c +++ b/src/test/test-fs-util.c @@ -270,17 +270,13 @@ static void test_chase_symlinks(void) { pfd = chase_symlinks(p, NULL, CHASE_OPEN, NULL); if (pfd != -ENOENT) { - char procfs[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(pfd) + 1]; _cleanup_close_ int fd = -1; sd_id128_t a, b; assert_se(pfd >= 0); - xsprintf(procfs, "/proc/self/fd/%i", pfd); - - fd = open(procfs, O_RDONLY|O_CLOEXEC); + fd = fd_reopen(pfd, O_RDONLY|O_CLOEXEC); assert_se(fd >= 0); - safe_close(pfd); assert_se(id128_read_fd(fd, ID128_PLAIN, &a) >= 0); |