1 //===-- Implementation of a class for mapping signals to strings ----------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "signal_to_string.h" 10 #include "platform_signals.h" 11 12 #include "src/__support/CPP/span.h" 13 #include "src/__support/CPP/string_view.h" 14 #include "src/__support/CPP/stringstream.h" 15 #include "src/__support/StringUtil/message_mapper.h" 16 #include "src/__support/integer_to_string.h" 17 #include "src/__support/macros/attributes.h" 18 #include "src/__support/macros/config.h" 19 20 #include <signal.h> 21 #include <stddef.h> 22 23 namespace LIBC_NAMESPACE_DECL { 24 namespace internal { 25 26 constexpr size_t max_buff_size() { 27 constexpr size_t base_str_len = sizeof("Real-time signal"); 28 // the buffer should be able to hold "Real-time signal" + ' ' + num_str 29 return (base_str_len + 1 + IntegerToString<int>::buffer_size()) * 30 sizeof(char); 31 } 32 33 // This is to hold signal strings that have to be custom built. It may be 34 // rewritten on every call to strsignal (or other signal to string function). 35 constexpr size_t SIG_BUFFER_SIZE = max_buff_size(); 36 LIBC_THREAD_LOCAL char signal_buffer[SIG_BUFFER_SIZE]; 37 38 constexpr size_t TOTAL_STR_LEN = total_str_len(PLATFORM_SIGNALS); 39 40 constexpr size_t SIG_ARRAY_SIZE = max_key_val(PLATFORM_SIGNALS) + 1; 41 42 constexpr MessageMapper<SIG_ARRAY_SIZE, TOTAL_STR_LEN> 43 signal_mapper(PLATFORM_SIGNALS); 44 45 cpp::string_view build_signal_string(int sig_num, cpp::span<char> buffer) { 46 cpp::string_view base_str; 47 if (sig_num >= SIGRTMIN && sig_num <= SIGRTMAX) { 48 base_str = cpp::string_view("Real-time signal"); 49 sig_num -= SIGRTMIN; 50 } else { 51 base_str = cpp::string_view("Unknown signal"); 52 } 53 54 // if the buffer can't hold "Unknown signal" + ' ' + num_str, then just 55 // return "Unknown signal". 56 if (buffer.size() < 57 (base_str.size() + 1 + IntegerToString<int>::buffer_size())) 58 return base_str; 59 60 cpp::StringStream buffer_stream( 61 {const_cast<char *>(buffer.data()), buffer.size()}); 62 buffer_stream << base_str << ' ' << sig_num << '\0'; 63 return buffer_stream.str(); 64 } 65 66 } // namespace internal 67 68 cpp::string_view get_signal_string(int sig_num) { 69 return get_signal_string( 70 sig_num, {internal::signal_buffer, internal::SIG_BUFFER_SIZE}); 71 } 72 73 cpp::string_view get_signal_string(int sig_num, cpp::span<char> buffer) { 74 auto opt_str = internal::signal_mapper.get_str(sig_num); 75 if (opt_str) 76 return *opt_str; 77 else 78 return internal::build_signal_string(sig_num, buffer); 79 } 80 81 } // namespace LIBC_NAMESPACE_DECL 82