1 #define SD_JOURNAL_SUPPRESS_LOCATION
2 
3 #include <systemd/sd-journal.h>
4 #include <unistd.h>
5 
6 #include <phosphor-logging/lg2.hpp>
7 
8 #include <algorithm>
9 #include <bitset>
10 #include <cstdarg>
11 #include <cstdio>
12 #include <iostream>
13 #include <mutex>
14 #include <source_location>
15 #include <sstream>
16 #include <vector>
17 
18 namespace lg2::details
19 {
20 /** Convert unsigned to string using format flags. */
21 static std::string value_to_string(uint64_t f, uint64_t v)
22 {
23     switch (f & (hex | bin | dec).value)
24     {
25         // For binary, use bitset<>::to_string.
26         // Treat values without a field-length format flag as 64 bit.
27         case bin.value:
28         {
29             switch (f & (field8 | field16 | field32 | field64).value)
30             {
31                 case field8.value:
32                 {
33                     return "0b" + std::bitset<8>(v).to_string();
34                 }
35                 case field16.value:
36                 {
37                     return "0b" + std::bitset<16>(v).to_string();
38                 }
39                 case field32.value:
40                 {
41                     return "0b" + std::bitset<32>(v).to_string();
42                 }
43                 case field64.value:
44                 default:
45                 {
46                     return "0b" + std::bitset<64>(v).to_string();
47                 }
48             }
49         }
50 
51         // For hex, use the appropriate sprintf.
52         case hex.value:
53         {
54             char value[19];
55             const char* format = nullptr;
56 
57             switch (f & (field8 | field16 | field32 | field64).value)
58             {
59                 case field8.value:
60                 {
61                     format = "0x%02" PRIx64;
62                     break;
63                 }
64 
65                 case field16.value:
66                 {
67                     format = "0x%04" PRIx64;
68                     break;
69                 }
70 
71                 case field32.value:
72                 {
73                     format = "0x%08" PRIx64;
74                     break;
75                 }
76 
77                 case field64.value:
78                 {
79                     format = "0x%016" PRIx64;
80                     break;
81                 }
82 
83                 default:
84                 {
85                     format = "0x%" PRIx64;
86                     break;
87                 }
88             }
89 
90             snprintf(value, sizeof(value), format, v);
91             return value;
92         }
93 
94         // For dec, use the simple to_string.
95         case dec.value:
96         default:
97         {
98             return std::to_string(v);
99         }
100     }
101 }
102 
103 /** Convert signed to string using format flags. */
104 static std::string value_to_string(uint64_t f, int64_t v)
105 {
106     // If hex or bin was requested just use the unsigned formatting
107     // rules. (What should a negative binary number look like otherwise?)
108     if (f & (hex | bin).value)
109     {
110         return value_to_string(f, static_cast<uint64_t>(v));
111     }
112     return std::to_string(v);
113 }
114 
115 /** Convert float to string using format flags. */
116 static std::string value_to_string(uint64_t, double v)
117 {
118     // No format flags supported for floats.
119     return std::to_string(v);
120 }
121 
122 // Positions of various strings in an iovec.
123 static constexpr size_t pos_msg = 0;
124 static constexpr size_t pos_fmtmsg = 1;
125 static constexpr size_t pos_prio = 2;
126 static constexpr size_t pos_file = 3;
127 static constexpr size_t pos_line = 4;
128 static constexpr size_t pos_func = 5;
129 static constexpr size_t static_locs = pos_func + 1;
130 
131 /** No-op output of a message. */
132 static void noop_extra_output(level, const std::source_location&,
133                               const std::string&)
134 {}
135 
136 /** std::cerr output of a message. */
137 static void cerr_extra_output(level l, const std::source_location& s,
138                               const std::string& m)
139 {
140     static const char* const defaultFormat = []() {
141         const char* f = getenv("LG2_FORMAT");
142         if (nullptr == f)
143         {
144             f = "<%l> %m";
145         }
146         return f;
147     }();
148 
149     const char* format = defaultFormat;
150 
151     std::stringstream stream;
152 
153     while (*format)
154     {
155         if (*format != '%')
156         {
157             stream << *format;
158             ++format;
159             continue;
160         }
161 
162         ++format;
163         switch (*format)
164         {
165             case '%':
166             case '\0':
167                 stream << '%';
168                 break;
169 
170             case 'f':
171                 stream << s.function_name();
172                 break;
173 
174             case 'F':
175                 stream << s.file_name();
176                 break;
177 
178             case 'l':
179                 stream << static_cast<uint64_t>(l);
180                 break;
181 
182             case 'L':
183                 stream << s.line();
184                 break;
185 
186             case 'm':
187                 stream << m;
188                 break;
189 
190             default:
191                 stream << '%' << *format;
192                 break;
193         }
194 
195         if (*format != '\0')
196         {
197             ++format;
198         }
199     }
200 
201     static std::mutex mutex;
202 
203     // Prevent multiple threads from clobbering the stderr lines of each other
204     std::scoped_lock lock(mutex);
205 
206     // Ensure this line makes it out before releasing mutex for next line
207     std::cerr << stream.str() << std::endl;
208 }
209 
210 // Use the cerr output method if we are on a TTY or if explicitly set via
211 // environment variable.
212 static auto extra_output_method = (isatty(fileno(stderr)) ||
213                                    nullptr != getenv("LG2_FORCE_STDERR"))
214                                       ? cerr_extra_output
215                                       : noop_extra_output;
216 
217 // Do_log implementation.
218 void do_log(level l, const std::source_location& s, const char* m, ...)
219 {
220     using namespace std::string_literals;
221 
222     std::vector<std::string> strings{static_locs};
223 
224     std::string message{m};
225 
226     // Assign all the static fields.
227     strings[pos_fmtmsg] = "LOG2_FMTMSG="s + m;
228     strings[pos_prio] = "PRIORITY="s + std::to_string(static_cast<uint64_t>(l));
229     strings[pos_file] = "CODE_FILE="s + s.file_name();
230     strings[pos_line] = "CODE_LINE="s + std::to_string(s.line());
231     strings[pos_func] = "CODE_FUNC="s + s.function_name();
232 
233     // Handle all the va_list args.
234     std::va_list args;
235     va_start(args, m);
236     while (true)
237     {
238         // Get the header out.
239         auto h_ptr = va_arg(args, const char*);
240         if (h_ptr == nullptr)
241         {
242             break;
243         }
244         std::string h{h_ptr};
245 
246         // Get the format flag.
247         auto f = va_arg(args, uint64_t);
248 
249         // Handle the value depending on which type format flag it has.
250         std::string value = {};
251         switch (f & (signed_val | unsigned_val | str | floating).value)
252         {
253             case signed_val.value:
254             {
255                 auto v = va_arg(args, int64_t);
256                 value = value_to_string(f, v);
257                 break;
258             }
259 
260             case unsigned_val.value:
261             {
262                 auto v = va_arg(args, uint64_t);
263                 value = value_to_string(f, v);
264                 break;
265             }
266 
267             case str.value:
268             {
269                 value = va_arg(args, const char*);
270                 break;
271             }
272 
273             case floating.value:
274             {
275                 auto v = va_arg(args, double);
276                 value = value_to_string(f, v);
277                 break;
278             }
279         }
280 
281         // Create the field for this value.
282         strings.emplace_back(h + '=' + value);
283 
284         // Check for {HEADER} in the message and replace with value.
285         auto h_brace = '{' + h + '}';
286         if (auto start = message.find(h_brace); start != std::string::npos)
287         {
288             message.replace(start, h_brace.size(), value);
289         }
290     }
291     va_end(args);
292 
293     // Add the final message into the strings array.
294     strings[pos_msg] = "MESSAGE="s + message.data();
295 
296     // Trasform strings -> iovec.
297     std::vector<iovec> iov{};
298     std::ranges::transform(strings, std::back_inserter(iov), [](auto& s) {
299         return iovec{s.data(), s.length()};
300     });
301 
302     // Output the iovec.
303     sd_journal_sendv(iov.data(), strings.size());
304     extra_output_method(l, s, message);
305 }
306 
307 } // namespace lg2::details
308