mirror of https://github.com/grpc/grpc.git
yang-g
4 years ago
parent
b7df39f095
commit
cf26f0133a
33 changed files with 250 additions and 49 deletions
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/*
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* |
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* Copyright 2020 gRPC authors. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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* |
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*/ |
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#include <grpc/support/port_platform.h> |
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#include "src/core/lib/gpr/strerror.h" |
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#include <array> |
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#include <cerrno> |
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#include <cstddef> |
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#include <cstdio> |
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#include <cstring> |
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#include <string> |
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#include <type_traits> |
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// The implementation below is mostly copied from abseil because it is internal
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// there.
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namespace grpc_core { |
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namespace { |
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// `ErrnoSaver` captures the value of `errno` upon construction and restores it
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// upon deletion. It is used in low-level code and must be super fast. Do not
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// add instrumentation, even in debug modes.
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class ErrnoSaver { |
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public: |
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ErrnoSaver() : saved_errno_(errno) {} |
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~ErrnoSaver() { errno = saved_errno_; } |
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int operator()() const { return saved_errno_; } |
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private: |
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const int saved_errno_; |
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}; |
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const char* StrErrorAdaptor(int errnum, char* buf, size_t buflen) { |
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#if defined(GPR_WINDOWS) |
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int rc = strerror_s(buf, buflen, errnum); |
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buf[buflen - 1] = '\0'; // guarantee NUL termination
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if (rc == 0 && strncmp(buf, "Unknown error", buflen) == 0) *buf = '\0'; |
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return buf; |
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#else |
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// The type of `ret` is platform-specific; both of these branches must compile
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// either way but only one will execute on any given platform:
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auto ret = strerror_r(errnum, buf, buflen); |
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if (std::is_same<decltype(ret), int>::value) { |
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// XSI `strerror_r`; `ret` is `int`:
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if (ret) *buf = '\0'; |
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return buf; |
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} else { |
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// GNU `strerror_r`; `ret` is `char *`:
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return reinterpret_cast<const char*>(ret); |
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} |
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#endif |
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} |
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std::string StrErrorInternal(int errnum) { |
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char buf[100]; |
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const char* str = StrErrorAdaptor(errnum, buf, sizeof buf); |
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if (*str == '\0') { |
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snprintf(buf, sizeof buf, "Unknown error %d", errnum); |
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str = buf; |
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} |
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return str; |
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} |
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// kSysNerr is the number of errors from a recent glibc. `StrError()` falls back
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// to `StrErrorAdaptor()` if the value is larger than this.
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constexpr int kSysNerr = 135; |
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std::array<std::string, kSysNerr>* NewStrErrorTable() { |
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auto* table = new std::array<std::string, kSysNerr>; |
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for (int i = 0; i < static_cast<int>(table->size()); ++i) { |
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(*table)[i] = StrErrorInternal(i); |
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} |
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return table; |
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} |
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} // namespace
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std::string StrError(int errnum) { |
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ErrnoSaver errno_saver; |
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static const auto* table = NewStrErrorTable(); |
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if (errnum >= 0 && errnum < static_cast<int>(table->size())) { |
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return (*table)[errnum]; |
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} |
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return StrErrorInternal(errnum); |
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} |
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} // namespace grpc_core
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@ -0,0 +1,35 @@ |
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/*
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* |
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* Copyright 2020 gRPC authors. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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* |
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*/ |
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#ifndef GRPC_CORE_LIB_GPR_STRERROR_H |
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#define GRPC_CORE_LIB_GPR_STRERROR_H |
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#include <grpc/support/port_platform.h> |
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#include <string> |
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namespace grpc_core { |
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// `strerror` is not thread-safe. This wrapper is a portable thread-safe
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// implementation. It does not modify `errno`.
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// The implementation is copied from abseil's internal.
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std::string StrError(int errnum); |
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} // namespace grpc_core
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#endif /* GRPC_CORE_LIB_GPR_STRERROR_H */ |
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