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
23namespace LIBC_NAMESPACE_DECL {
24namespace internal {
25
26constexpr 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).
35constexpr size_t SIG_BUFFER_SIZE = max_buff_size();
36LIBC_THREAD_LOCAL char signal_buffer[SIG_BUFFER_SIZE];
37
38constexpr size_t TOTAL_STR_LEN = total_str_len(PLATFORM_SIGNALS);
39
40constexpr size_t SIG_ARRAY_SIZE = max_key_val(PLATFORM_SIGNALS) + 1;
41
42constexpr MessageMapper<SIG_ARRAY_SIZE, TOTAL_STR_LEN>
43 signal_mapper(PLATFORM_SIGNALS);
44
45cpp::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
68cpp::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
73cpp::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

source code of libc/src/__support/StringUtil/signal_to_string.cpp