From 2910aa77b2feea39fc0618598e275b138a346e71 Mon Sep 17 00:00:00 2001 From: comex Date: Sun, 24 Jan 2021 15:17:02 -0500 Subject: [network] Error handling reform `network.cpp` has several error paths which either: - report "Unhandled host socket error=n" and return `SUCCESS`, or - switch on a few possible errors, log them, and translate them to Errno; the same switch statement is copied and pasted in multiple places in the code Convert these paths to use a helper function `GetAndLogLastError`, which is roughly the equivalent of one of the switch statements, but: - handling more cases (both ones that were already in `Errno`, and a few more I added), and - using OS functions to convert the error to a string when logging, so it'll describe the error even if it's not one of the ones in the switch statement. - To handle this, refactor the logic in `GetLastErrorMsg` to expose a new function `NativeErrorToString` which takes the error number explicitly as an argument. And improve the Windows version a bit. Also, add a test which exercises two random error paths. --- src/common/common_funcs.h | 6 +++++- src/common/misc.cpp | 44 +++++++++++++++++++++++++++++--------------- 2 files changed, 34 insertions(+), 16 deletions(-) (limited to 'src/common') diff --git a/src/common/common_funcs.h b/src/common/common_funcs.h index 71b64e32a..4ace2cd33 100644 --- a/src/common/common_funcs.h +++ b/src/common/common_funcs.h @@ -52,9 +52,13 @@ __declspec(dllimport) void __stdcall DebugBreak(void); // Generic function to get last error message. // Call directly after the command or use the error num. // This function might change the error code. -// Defined in Misc.cpp. +// Defined in misc.cpp. [[nodiscard]] std::string GetLastErrorMsg(); +// Like GetLastErrorMsg(), but passing an explicit error code. +// Defined in misc.cpp. +[[nodiscard]] std::string NativeErrorToString(int e); + #define DECLARE_ENUM_FLAG_OPERATORS(type) \ [[nodiscard]] constexpr type operator|(type a, type b) noexcept { \ using T = std::underlying_type_t; \ diff --git a/src/common/misc.cpp b/src/common/misc.cpp index 1d5393597..495385b9e 100644 --- a/src/common/misc.cpp +++ b/src/common/misc.cpp @@ -12,27 +12,41 @@ #include "common/common_funcs.h" -// Generic function to get last error message. -// Call directly after the command or use the error num. -// This function might change the error code. -std::string GetLastErrorMsg() { - static constexpr std::size_t buff_size = 255; - char err_str[buff_size]; - +std::string NativeErrorToString(int e) { #ifdef _WIN32 - FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, nullptr, GetLastError(), - MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), err_str, buff_size, nullptr); - return std::string(err_str, buff_size); -#elif defined(__GLIBC__) && (_GNU_SOURCE || (_POSIX_C_SOURCE < 200112L && _XOPEN_SOURCE < 600)) + LPSTR err_str; + + DWORD res = FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER | + FORMAT_MESSAGE_IGNORE_INSERTS, + nullptr, e, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), + reinterpret_cast(&err_str), 1, nullptr); + if (!res) { + return "(FormatMessageA failed to format error)"; + } + std::string ret(err_str); + LocalFree(err_str); + return ret; +#else + char err_str[255]; +#if defined(__GLIBC__) && (_GNU_SOURCE || (_POSIX_C_SOURCE < 200112L && _XOPEN_SOURCE < 600)) // Thread safe (GNU-specific) - const char* str = strerror_r(errno, err_str, buff_size); + const char* str = strerror_r(e, err_str, sizeof(err_str)); return std::string(str); #else // Thread safe (XSI-compliant) - const int success = strerror_r(errno, err_str, buff_size); - if (success != 0) { - return {}; + int second_err = strerror_r(e, err_str, sizeof(err_str)); + if (second_err != 0) { + return "(strerror_r failed to format error)"; } return std::string(err_str); +#endif // GLIBC etc. +#endif // _WIN32 +} + +std::string GetLastErrorMsg() { +#ifdef _WIN32 + return NativeErrorToString(GetLastError()); +#else + return NativeErrorToString(errno); #endif } -- cgit v1.2.3