linux/tools/lib/bpf/libbpf_errno.c
Xin Liu c9883ee9d1 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: Xin Liu <liuxin350@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20221210082045.233697-1-liuxin350@huawei.com
2022-12-14 18:39:33 +01:00

76 lines
2.3 KiB
C

// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/*
* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
* Copyright (C) 2015 Huawei Inc.
* Copyright (C) 2017 Nicira, Inc.
*/
#undef _GNU_SOURCE
#include <stdio.h>
#include <string.h>
#include "libbpf.h"
#include "libbpf_internal.h"
/* make sure libbpf doesn't use kernel-only integer typedefs */
#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
#define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START)
#define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c)
#define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
static const char *libbpf_strerror_table[NR_ERRNO] = {
[ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf",
[ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid",
[ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost",
[ERRCODE_OFFSET(ENDIAN)] = "Endian mismatch",
[ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf",
[ERRCODE_OFFSET(RELOC)] = "Relocation failed",
[ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
[ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
[ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
[ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type",
[ERRCODE_OFFSET(WRNGPID)] = "Wrong pid in netlink message",
[ERRCODE_OFFSET(INVSEQ)] = "Invalid netlink sequence",
[ERRCODE_OFFSET(NLPARSE)] = "Incorrect netlink message parsing",
};
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) {
ret = strerror_r(err, buf, size);
buf[size - 1] = '\0';
return libbpf_err_errno(ret);
}
if (err < __LIBBPF_ERRNO__END) {
const char *msg;
msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
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;
}
ret = snprintf(buf, size, "Unknown libbpf error %d", err);
buf[size - 1] = '\0';
if (ret >= size)
return libbpf_err(-ERANGE);
return libbpf_err(-ENOENT);
}