From fe4cb796df46b5b5801ee2d397243ae7e9271b9c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Sat, 2 Nov 2019 12:09:37 +0100 Subject: [PATCH] libbpf: Fix error handling in bpf_map__reuse_fd() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit bpf_map__reuse_fd() was calling close() in the error path before returning an error value based on errno. However, close can change errno, so that can lead to potentially misleading error messages. Instead, explicitly store errno in the err variable before each goto. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/157269297769.394725.12634985106772698611.stgit@toke.dk --- src/libbpf.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/src/libbpf.c b/src/libbpf.c index c80f316..36152c8 100644 --- a/src/libbpf.c +++ b/src/libbpf.c @@ -1917,16 +1917,22 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd) return -errno; new_fd = open("/", O_RDONLY | O_CLOEXEC); - if (new_fd < 0) + if (new_fd < 0) { + err = -errno; goto err_free_new_name; + } new_fd = dup3(fd, new_fd, O_CLOEXEC); - if (new_fd < 0) + if (new_fd < 0) { + err = -errno; goto err_close_new_fd; + } err = zclose(map->fd); - if (err) + if (err) { + err = -errno; goto err_close_new_fd; + } free(map->name); map->fd = new_fd; @@ -1945,7 +1951,7 @@ err_close_new_fd: close(new_fd); err_free_new_name: free(new_name); - return -errno; + return err; } int bpf_map__resize(struct bpf_map *map, __u32 max_entries)