Messages in this thread Patch in this message | | | From | Xin Liu <> | Subject | [PATCH bpf-next] libbpf: fix errno is overwritten after being closed. | Date | Fri, 23 Dec 2022 21:36:18 +0800 |
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In the ensure_good_fd function, if the fcntl function succeeds but the close function fails, ensure_good_fd returns a normal fd and sets errno, which may cause users to misunderstand. The close failure is not a serious problem, and the correct FD has been handed over to the upper-layer application. Let's restore errno here.
Signed-off-by: Xin Liu <liuxin350@huawei.com> --- tools/lib/bpf/libbpf_internal.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 377642ff51fc..98333a6c38e9 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -543,10 +543,9 @@ static inline int ensure_good_fd(int fd) fd = fcntl(fd, F_DUPFD_CLOEXEC, 3); saved_errno = errno; close(old_fd); - if (fd < 0) { + errno = saved_errno; + if (fd < 0) pr_warn("failed to dup FD %d to FD > 2: %d\n", old_fd, -saved_errno); - errno = saved_errno; - } } return fd; } -- 2.33.0
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