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e9fc3ce99b
Implement changes to error reporting for high-level libbpf APIs to make them
less surprising and less error-prone to users:
- in all the cases when error happens, errno is set to an appropriate error
value;
- in libbpf 1.0 mode, all pointer-returning APIs return NULL on error and
error code is communicated through errno; this applies both to APIs that
already returned NULL before (so now they communicate more detailed error
codes), as well as for many APIs that used ERR_PTR() macro and encoded
error numbers as fake pointers.
- in legacy (default) mode, those APIs that were returning ERR_PTR(err),
continue doing so, but still set errno.
With these changes, errno can be always used to extract actual error,
regardless of legacy or libbpf 1.0 modes. This is utilized internally in
libbpf in places where libbpf uses it's own high-level APIs.
libbpf_get_error() is adapted to handle both cases completely transparently to
end-users (and is used by libbpf consistently as well).
More context, justification, and discussion can be found in "Libbpf: the road
to v1.0" document ([0]).
[0] https://docs.google.com/document/d/1UyjTZuPFWiPFyKk1tV5an11_iaRuec6U-ZESZ54nNTY
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210525035935.1461796-5-andrii@kernel.org
68 lines
2.0 KiB
C
68 lines
2.0 KiB
C
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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/*
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* Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
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* Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
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* Copyright (C) 2015 Huawei Inc.
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* Copyright (C) 2017 Nicira, Inc.
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*/
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#undef _GNU_SOURCE
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#include <stdio.h>
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#include <string.h>
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#include "libbpf.h"
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#include "libbpf_internal.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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#define ERRNO_OFFSET(e) ((e) - __LIBBPF_ERRNO__START)
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#define ERRCODE_OFFSET(c) ERRNO_OFFSET(LIBBPF_ERRNO__##c)
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#define NR_ERRNO (__LIBBPF_ERRNO__END - __LIBBPF_ERRNO__START)
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static const char *libbpf_strerror_table[NR_ERRNO] = {
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[ERRCODE_OFFSET(LIBELF)] = "Something wrong in libelf",
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[ERRCODE_OFFSET(FORMAT)] = "BPF object format invalid",
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[ERRCODE_OFFSET(KVERSION)] = "'version' section incorrect or lost",
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[ERRCODE_OFFSET(ENDIAN)] = "Endian mismatch",
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[ERRCODE_OFFSET(INTERNAL)] = "Internal error in libbpf",
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[ERRCODE_OFFSET(RELOC)] = "Relocation failed",
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[ERRCODE_OFFSET(VERIFY)] = "Kernel verifier blocks program loading",
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[ERRCODE_OFFSET(PROG2BIG)] = "Program too big",
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[ERRCODE_OFFSET(KVER)] = "Incorrect kernel version",
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[ERRCODE_OFFSET(PROGTYPE)] = "Kernel doesn't support this program type",
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[ERRCODE_OFFSET(WRNGPID)] = "Wrong pid in netlink message",
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[ERRCODE_OFFSET(INVSEQ)] = "Invalid netlink sequence",
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[ERRCODE_OFFSET(NLPARSE)] = "Incorrect netlink message parsing",
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};
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int libbpf_strerror(int err, char *buf, size_t size)
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{
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if (!buf || !size)
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return libbpf_err(-EINVAL);
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err = err > 0 ? err : -err;
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if (err < __LIBBPF_ERRNO__START) {
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int ret;
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ret = strerror_r(err, buf, size);
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buf[size - 1] = '\0';
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return libbpf_err_errno(ret);
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}
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if (err < __LIBBPF_ERRNO__END) {
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const char *msg;
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msg = libbpf_strerror_table[ERRNO_OFFSET(err)];
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snprintf(buf, size, "%s", msg);
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buf[size - 1] = '\0';
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return 0;
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}
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snprintf(buf, size, "Unknown libbpf error %d", err);
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buf[size - 1] = '\0';
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return libbpf_err(-ENOENT);
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}
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