Re: [PATCH bpf] samples/bpf: Fix the error return code of xdp_redirect's main()
From: Jesper Dangaard Brouer <hidden>
Date: 2021-07-02 10:29:43
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On 16/06/2021 06.25, Wang Hai wrote:
Fix to return a negative error code from the error handling case instead of 0, as done elsewhere in this function.
The main() function in C should never return a negative value on Unix POSIX systems. There is a good explaination in exit(3p): `man 3p exit` The value of status may be 0, EXIT_SUCCESS, EXIT_FAILURE, or any other value, though only the least significant 8 bits (that is, status & 0377) shall be available to a waiting parent process. Thus, negative values are often seen as 255 in the $? program exit status variable $?. Also explained in exit(3): The C standard specifies two constants, EXIT_SUCCESS=0 and EXIT_FAILURE=1. I see the 'samples/bpf/xdp_redirect_user.c' in most places just use 0 or 1.
quoted hunk ↗ jump to hunk
If bpf_map_update_elem() failed, main() should return a negative error. Fixes: 832622e6bd18 ("xdp: sample program for new bpf_redirect helper") Signed-off-by: Wang Hai <redacted> --- samples/bpf/xdp_redirect_user.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/samples/bpf/xdp_redirect_user.c b/samples/bpf/xdp_redirect_user.c index 41d705c3a1f7..c903f1ccc15e 100644 --- a/samples/bpf/xdp_redirect_user.c +++ b/samples/bpf/xdp_redirect_user.c@@ -213,5 +213,5 @@ int main(int argc, char **argv) poll_stats(2, ifindex_out); out: - return 0; + return ret; }
(Sorry, I didn't complain it time as I see this patch is already applied)