1 //===-- Log.cpp -------------------------------------------------*- C++ -*-===//
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 "lldb/Utility/Log.h"
10 #include "lldb/Utility/VASPrintf.h"
11 
12 #include "llvm/ADT/SmallString.h"
13 #include "llvm/ADT/Twine.h"
14 #include "llvm/ADT/iterator.h"
15 
16 #include "llvm/Support/Chrono.h"
17 #include "llvm/Support/ManagedStatic.h"
18 #include "llvm/Support/Path.h"
19 #include "llvm/Support/Signals.h"
20 #include "llvm/Support/Threading.h"
21 #include "llvm/Support/raw_ostream.h"
22 
23 #include <chrono>
24 #include <cstdarg>
25 #include <mutex>
26 #include <utility>
27 
28 #include <assert.h>
29 #if defined(_WIN32)
30 #include <process.h>
31 #else
32 #include <unistd.h>
33 #include <pthread.h>
34 #endif
35 
36 using namespace lldb_private;
37 
38 llvm::ManagedStatic<Log::ChannelMap> Log::g_channel_map;
39 
40 void Log::ForEachCategory(
41     const Log::ChannelMap::value_type &entry,
42     llvm::function_ref<void(llvm::StringRef, llvm::StringRef)> lambda) {
43   lambda("all", "all available logging categories");
44   lambda("default", "default set of logging categories");
45   for (const auto &category : entry.second.m_channel.categories)
46     lambda(category.name, category.description);
47 }
48 
49 void Log::ListCategories(llvm::raw_ostream &stream,
50                          const ChannelMap::value_type &entry) {
51   stream << llvm::formatv("Logging categories for '{0}':\n", entry.first());
52   ForEachCategory(entry,
53                   [&stream](llvm::StringRef name, llvm::StringRef description) {
54                     stream << llvm::formatv("  {0} - {1}\n", name, description);
55                   });
56 }
57 
58 uint32_t Log::GetFlags(llvm::raw_ostream &stream, const ChannelMap::value_type &entry,
59                          llvm::ArrayRef<const char *> categories) {
60   bool list_categories = false;
61   uint32_t flags = 0;
62   for (const char *category : categories) {
63     if (llvm::StringRef("all").equals_lower(category)) {
64       flags |= UINT32_MAX;
65       continue;
66     }
67     if (llvm::StringRef("default").equals_lower(category)) {
68       flags |= entry.second.m_channel.default_flags;
69       continue;
70     }
71     auto cat = llvm::find_if(
72         entry.second.m_channel.categories,
73         [&](const Log::Category &c) { return c.name.equals_lower(category); });
74     if (cat != entry.second.m_channel.categories.end()) {
75       flags |= cat->flag;
76       continue;
77     }
78     stream << llvm::formatv("error: unrecognized log category '{0}'\n",
79                             category);
80     list_categories = true;
81   }
82   if (list_categories)
83     ListCategories(stream, entry);
84   return flags;
85 }
86 
87 void Log::Enable(const std::shared_ptr<llvm::raw_ostream> &stream_sp,
88                  uint32_t options, uint32_t flags) {
89   llvm::sys::ScopedWriter lock(m_mutex);
90 
91   uint32_t mask = m_mask.fetch_or(flags, std::memory_order_relaxed);
92   if (mask | flags) {
93     m_options.store(options, std::memory_order_relaxed);
94     m_stream_sp = stream_sp;
95     m_channel.log_ptr.store(this, std::memory_order_relaxed);
96   }
97 }
98 
99 void Log::Disable(uint32_t flags) {
100   llvm::sys::ScopedWriter lock(m_mutex);
101 
102   uint32_t mask = m_mask.fetch_and(~flags, std::memory_order_relaxed);
103   if (!(mask & ~flags)) {
104     m_stream_sp.reset();
105     m_channel.log_ptr.store(nullptr, std::memory_order_relaxed);
106   }
107 }
108 
109 const Flags Log::GetOptions() const {
110   return m_options.load(std::memory_order_relaxed);
111 }
112 
113 const Flags Log::GetMask() const {
114   return m_mask.load(std::memory_order_relaxed);
115 }
116 
117 void Log::PutCString(const char *cstr) { Printf("%s", cstr); }
118 void Log::PutString(llvm::StringRef str) { PutCString(str.str().c_str()); }
119 
120 // Simple variable argument logging with flags.
121 void Log::Printf(const char *format, ...) {
122   va_list args;
123   va_start(args, format);
124   VAPrintf(format, args);
125   va_end(args);
126 }
127 
128 // All logging eventually boils down to this function call. If we have a
129 // callback registered, then we call the logging callback. If we have a valid
130 // file handle, we also log to the file.
131 void Log::VAPrintf(const char *format, va_list args) {
132   llvm::SmallString<64> FinalMessage;
133   llvm::raw_svector_ostream Stream(FinalMessage);
134   WriteHeader(Stream, "", "");
135 
136   llvm::SmallString<64> Content;
137   lldb_private::VASprintf(Content, format, args);
138 
139   Stream << Content << "\n";
140 
141   WriteMessage(FinalMessage.str());
142 }
143 
144 // Printing of errors that are not fatal.
145 void Log::Error(const char *format, ...) {
146   va_list args;
147   va_start(args, format);
148   VAError(format, args);
149   va_end(args);
150 }
151 
152 void Log::VAError(const char *format, va_list args) {
153   llvm::SmallString<64> Content;
154   VASprintf(Content, format, args);
155 
156   Printf("error: %s", Content.c_str());
157 }
158 
159 // Printing of warnings that are not fatal only if verbose mode is enabled.
160 void Log::Verbose(const char *format, ...) {
161   if (!GetVerbose())
162     return;
163 
164   va_list args;
165   va_start(args, format);
166   VAPrintf(format, args);
167   va_end(args);
168 }
169 
170 // Printing of warnings that are not fatal.
171 void Log::Warning(const char *format, ...) {
172   llvm::SmallString<64> Content;
173   va_list args;
174   va_start(args, format);
175   VASprintf(Content, format, args);
176   va_end(args);
177 
178   Printf("warning: %s", Content.c_str());
179 }
180 
181 void Log::Initialize() {
182 #ifdef LLVM_ON_UNIX
183   pthread_atfork(nullptr, nullptr, &Log::DisableLoggingChild);
184 #endif
185   InitializeLldbChannel();
186 }
187 
188 void Log::Register(llvm::StringRef name, Channel &channel) {
189   auto iter = g_channel_map->try_emplace(name, channel);
190   assert(iter.second == true);
191   (void)iter;
192 }
193 
194 void Log::Unregister(llvm::StringRef name) {
195   auto iter = g_channel_map->find(name);
196   assert(iter != g_channel_map->end());
197   iter->second.Disable(UINT32_MAX);
198   g_channel_map->erase(iter);
199 }
200 
201 bool Log::EnableLogChannel(
202     const std::shared_ptr<llvm::raw_ostream> &log_stream_sp,
203     uint32_t log_options, llvm::StringRef channel,
204     llvm::ArrayRef<const char *> categories, llvm::raw_ostream &error_stream) {
205   auto iter = g_channel_map->find(channel);
206   if (iter == g_channel_map->end()) {
207     error_stream << llvm::formatv("Invalid log channel '{0}'.\n", channel);
208     return false;
209   }
210   uint32_t flags = categories.empty()
211                        ? iter->second.m_channel.default_flags
212                        : GetFlags(error_stream, *iter, categories);
213   iter->second.Enable(log_stream_sp, log_options, flags);
214   return true;
215 }
216 
217 bool Log::DisableLogChannel(llvm::StringRef channel,
218                             llvm::ArrayRef<const char *> categories,
219                             llvm::raw_ostream &error_stream) {
220   auto iter = g_channel_map->find(channel);
221   if (iter == g_channel_map->end()) {
222     error_stream << llvm::formatv("Invalid log channel '{0}'.\n", channel);
223     return false;
224   }
225   uint32_t flags = categories.empty()
226                        ? UINT32_MAX
227                        : GetFlags(error_stream, *iter, categories);
228   iter->second.Disable(flags);
229   return true;
230 }
231 
232 bool Log::ListChannelCategories(llvm::StringRef channel,
233                                 llvm::raw_ostream &stream) {
234   auto ch = g_channel_map->find(channel);
235   if (ch == g_channel_map->end()) {
236     stream << llvm::formatv("Invalid log channel '{0}'.\n", channel);
237     return false;
238   }
239   ListCategories(stream, *ch);
240   return true;
241 }
242 
243 void Log::DisableAllLogChannels() {
244   for (auto &entry : *g_channel_map)
245     entry.second.Disable(UINT32_MAX);
246 }
247 
248 void Log::ForEachChannelCategory(
249     llvm::StringRef channel,
250     llvm::function_ref<void(llvm::StringRef, llvm::StringRef)> lambda) {
251   auto ch = g_channel_map->find(channel);
252   if (ch == g_channel_map->end())
253     return;
254 
255   ForEachCategory(*ch, lambda);
256 }
257 
258 std::vector<llvm::StringRef> Log::ListChannels() {
259   std::vector<llvm::StringRef> result;
260   for (const auto &channel : *g_channel_map)
261     result.push_back(channel.first());
262   return result;
263 }
264 
265 void Log::ListAllLogChannels(llvm::raw_ostream &stream) {
266   if (g_channel_map->empty()) {
267     stream << "No logging channels are currently registered.\n";
268     return;
269   }
270 
271   for (const auto &channel : *g_channel_map)
272     ListCategories(stream, channel);
273 }
274 
275 bool Log::GetVerbose() const {
276   return m_options.load(std::memory_order_relaxed) & LLDB_LOG_OPTION_VERBOSE;
277 }
278 
279 void Log::WriteHeader(llvm::raw_ostream &OS, llvm::StringRef file,
280                       llvm::StringRef function) {
281   Flags options = GetOptions();
282   static uint32_t g_sequence_id = 0;
283   // Add a sequence ID if requested
284   if (options.Test(LLDB_LOG_OPTION_PREPEND_SEQUENCE))
285     OS << ++g_sequence_id << " ";
286 
287   // Timestamp if requested
288   if (options.Test(LLDB_LOG_OPTION_PREPEND_TIMESTAMP)) {
289     auto now = std::chrono::duration<double>(
290         std::chrono::system_clock::now().time_since_epoch());
291     OS << llvm::formatv("{0:f9} ", now.count());
292   }
293 
294   // Add the process and thread if requested
295   if (options.Test(LLDB_LOG_OPTION_PREPEND_PROC_AND_THREAD))
296     OS << llvm::formatv("[{0,0+4}/{1,0+4}] ", getpid(),
297                         llvm::get_threadid());
298 
299   // Add the thread name if requested
300   if (options.Test(LLDB_LOG_OPTION_PREPEND_THREAD_NAME)) {
301     llvm::SmallString<32> thread_name;
302     llvm::get_thread_name(thread_name);
303 
304     llvm::SmallString<12> format_str;
305     llvm::raw_svector_ostream format_os(format_str);
306     format_os << "{0,-" << llvm::alignTo<16>(thread_name.size()) << "} ";
307     OS << llvm::formatv(format_str.c_str(), thread_name);
308   }
309 
310   if (options.Test(LLDB_LOG_OPTION_BACKTRACE))
311     llvm::sys::PrintStackTrace(OS);
312 
313   if (options.Test(LLDB_LOG_OPTION_PREPEND_FILE_FUNCTION) &&
314       (!file.empty() || !function.empty())) {
315     file = llvm::sys::path::filename(file).take_front(40);
316     function = function.take_front(40);
317     OS << llvm::formatv("{0,-60:60} ", (file + ":" + function).str());
318   }
319 }
320 
321 void Log::WriteMessage(const std::string &message) {
322   // Make a copy of our stream shared pointer in case someone disables our log
323   // while we are logging and releases the stream
324   auto stream_sp = GetStream();
325   if (!stream_sp)
326     return;
327 
328   Flags options = GetOptions();
329   if (options.Test(LLDB_LOG_OPTION_THREADSAFE)) {
330     static std::recursive_mutex g_LogThreadedMutex;
331     std::lock_guard<std::recursive_mutex> guard(g_LogThreadedMutex);
332     *stream_sp << message;
333     stream_sp->flush();
334   } else {
335     *stream_sp << message;
336     stream_sp->flush();
337   }
338 }
339 
340 void Log::Format(llvm::StringRef file, llvm::StringRef function,
341                  const llvm::formatv_object_base &payload) {
342   std::string message_string;
343   llvm::raw_string_ostream message(message_string);
344   WriteHeader(message, file, function);
345   message << payload << "\n";
346   WriteMessage(message.str());
347 }
348 
349 void Log::DisableLoggingChild() {
350   // Disable logging by clearing out the atomic variable after forking -- if we
351   // forked while another thread held the channel mutex, we would deadlock when
352   // trying to write to the log.
353   for (auto &c: *g_channel_map)
354     c.second.m_channel.log_ptr.store(nullptr, std::memory_order_relaxed);
355 }
356