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548c2ede0d
strerror_r(), used from libbpf-specific libbpf_strerror_r() wrapper is documented to return error in two different ways, depending on glibc version. Take that into account when handling strerror_r()'s own errors, which happens when we pass some non-standard (internal) kernel error to it. Before this patch we'd have "ERROR: strerror_r(524)=22", which is quite confusing. Now for the same situation we'll see a bit less visually scary "unknown error (-524)". At least we won't confuse user with irrelevant EINVAL (22). Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240507001335.1445325-5-andrii@kernel.org Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
34 lines
1020 B
C
34 lines
1020 B
C
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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#undef _GNU_SOURCE
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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#include "str_error.h"
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/* make sure libbpf doesn't use kernel-only integer typedefs */
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#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
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/*
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* Wrapper to allow for building in non-GNU systems such as Alpine Linux's musl
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* libc, while checking strerror_r() return to avoid having to check this in
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* all places calling it.
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*/
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char *libbpf_strerror_r(int err, char *dst, int len)
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{
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int ret = strerror_r(err < 0 ? -err : err, dst, len);
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/* on glibc <2.13, ret == -1 and errno is set, if strerror_r() can't
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* handle the error, on glibc >=2.13 *positive* (errno-like) error
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* code is returned directly
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*/
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if (ret == -1)
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ret = errno;
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if (ret) {
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if (ret == EINVAL)
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/* strerror_r() doesn't recognize this specific error */
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snprintf(dst, len, "unknown error (%d)", err < 0 ? err : -err);
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else
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snprintf(dst, len, "ERROR: strerror_r(%d)=%d", err, ret);
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}
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return dst;
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}
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