Commit c9883ee9 authored by Xin Liu's avatar Xin Liu Committed by Daniel Borkmann
Browse files

libbpf: Optimized return value in libbpf_strerror when errno is libbpf errno 



This is a small improvement in libbpf_strerror. When libbpf_strerror
is used to obtain the system error description, if the length of the
buf is insufficient, libbpf_sterror returns ERANGE and sets errno to
ERANGE.

However, this processing is not performed when the error code
customized by libbpf is obtained. Make some minor improvements here,
return -ERANGE and set errno to ERANGE when buf is not enough for
custom description.

Signed-off-by: default avatarXin Liu <liuxin350@huawei.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20221210082045.233697-1-liuxin350@huawei.com
parent 7e68dd7d

tools/lib/bpf/libbpf_errno.c

+12 −4
Original line number Diff line number Diff line
@@ -39,14 +39,14 @@ static const char *libbpf_strerror_table[NR_ERRNO] = { 


int libbpf_strerror(int err, char *buf, size_t size)

{

	int ret;



	if (!buf || !size)

		return libbpf_err(-EINVAL);



	err = err > 0 ? err : -err;



	if (err < __LIBBPF_ERRNO__START) {

		int ret;



		ret = strerror_r(err, buf, size);

		buf[size - 1] = '\0';

		return libbpf_err_errno(ret);
@@ -56,12 +56,20 @@ int libbpf_strerror(int err, char *buf, size_t size) 
		const char *msg;



		msg = libbpf_strerror_table[ERRNO_OFFSET(err)];

		snprintf(buf, size, "%s", msg);

		ret = snprintf(buf, size, "%s", msg);

		buf[size - 1] = '\0';

		/* The length of the buf and msg is positive.

		 * A negative number may be returned only when the

		 * size exceeds INT_MAX. Not likely to appear.

		 */

		if (ret >= size)

			return libbpf_err(-ERANGE);

		return 0;

	}



	snprintf(buf, size, "Unknown libbpf error %d", err);

	ret = snprintf(buf, size, "Unknown libbpf error %d", err);

	buf[size - 1] = '\0';

	if (ret >= size)

		return libbpf_err(-ERANGE);

	return libbpf_err(-ENOENT);

}