1 //===-- UnixSignals.cpp ---------------------------------------------------===//
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/Target/UnixSignals.h"
10 #include "Plugins/Process/Utility/FreeBSDSignals.h"
11 #include "Plugins/Process/Utility/LinuxSignals.h"
12 #include "Plugins/Process/Utility/NetBSDSignals.h"
13 #include "lldb/Host/HostInfo.h"
14 #include "lldb/Utility/ArchSpec.h"
15 #include <optional>
16 #include <sstream>
17 
18 using namespace lldb_private;
19 using namespace llvm;
20 
21 UnixSignals::Signal::Signal(const char *name, bool default_suppress,
22                             bool default_stop, bool default_notify,
23                             const char *description, const char *alias)
24     : m_name(name), m_alias(alias), m_description(),
25       m_suppress(default_suppress), m_stop(default_stop),
26       m_notify(default_notify),
27       m_default_suppress(default_suppress), m_default_stop(default_stop),
28       m_default_notify(default_notify) {
29   if (description)
30     m_description.assign(description);
31 }
32 
33 lldb::UnixSignalsSP UnixSignals::Create(const ArchSpec &arch) {
34   const auto &triple = arch.GetTriple();
35   switch (triple.getOS()) {
36   case llvm::Triple::Linux:
37     return std::make_shared<LinuxSignals>();
38   case llvm::Triple::FreeBSD:
39   case llvm::Triple::OpenBSD:
40     return std::make_shared<FreeBSDSignals>();
41   case llvm::Triple::NetBSD:
42     return std::make_shared<NetBSDSignals>();
43   default:
44     return std::make_shared<UnixSignals>();
45   }
46 }
47 
48 lldb::UnixSignalsSP UnixSignals::CreateForHost() {
49   static lldb::UnixSignalsSP s_unix_signals_sp =
50       Create(HostInfo::GetArchitecture());
51   return s_unix_signals_sp;
52 }
53 
54 // UnixSignals constructor
55 UnixSignals::UnixSignals() { Reset(); }
56 
57 UnixSignals::UnixSignals(const UnixSignals &rhs) : m_signals(rhs.m_signals) {}
58 
59 UnixSignals::~UnixSignals() = default;
60 
61 void UnixSignals::Reset() {
62   // This builds one standard set of Unix Signals. If yours aren't quite in
63   // this order, you can either subclass this class, and use Add & Remove to
64   // change them or you can subclass and build them afresh in your constructor.
65   //
66   // Note: the signals below are the Darwin signals. Do not change these!
67 
68   m_signals.clear();
69 
70   // clang-format off
71   //        SIGNO   NAME            SUPPRESS  STOP    NOTIFY  DESCRIPTION
72   //        ======  ==============  ========  ======  ======  ===================================================
73   AddSignal(1,      "SIGHUP",       false,    true,   true,   "hangup");
74   AddSignal(2,      "SIGINT",       true,     true,   true,   "interrupt");
75   AddSignal(3,      "SIGQUIT",      false,    true,   true,   "quit");
76   AddSignal(4,      "SIGILL",       false,    true,   true,   "illegal instruction");
77   AddSignal(5,      "SIGTRAP",      true,     true,   true,   "trace trap (not reset when caught)");
78   AddSignal(6,      "SIGABRT",      false,    true,   true,   "abort()");
79   AddSignal(7,      "SIGEMT",       false,    true,   true,   "pollable event");
80   AddSignal(8,      "SIGFPE",       false,    true,   true,   "floating point exception");
81   AddSignal(9,      "SIGKILL",      false,    true,   true,   "kill");
82   AddSignal(10,     "SIGBUS",       false,    true,   true,   "bus error");
83   AddSignal(11,     "SIGSEGV",      false,    true,   true,   "segmentation violation");
84   AddSignal(12,     "SIGSYS",       false,    true,   true,   "bad argument to system call");
85   AddSignal(13,     "SIGPIPE",      false,    false,  false,  "write on a pipe with no one to read it");
86   AddSignal(14,     "SIGALRM",      false,    false,  false,  "alarm clock");
87   AddSignal(15,     "SIGTERM",      false,    true,   true,   "software termination signal from kill");
88   AddSignal(16,     "SIGURG",       false,    false,  false,  "urgent condition on IO channel");
89   AddSignal(17,     "SIGSTOP",      true,     true,   true,   "sendable stop signal not from tty");
90   AddSignal(18,     "SIGTSTP",      false,    true,   true,   "stop signal from tty");
91   AddSignal(19,     "SIGCONT",      false,    false,  true,   "continue a stopped process");
92   AddSignal(20,     "SIGCHLD",      false,    false,  false,  "to parent on child stop or exit");
93   AddSignal(21,     "SIGTTIN",      false,    true,   true,   "to readers process group upon background tty read");
94   AddSignal(22,     "SIGTTOU",      false,    true,   true,   "to readers process group upon background tty write");
95   AddSignal(23,     "SIGIO",        false,    false,  false,  "input/output possible signal");
96   AddSignal(24,     "SIGXCPU",      false,    true,   true,   "exceeded CPU time limit");
97   AddSignal(25,     "SIGXFSZ",      false,    true,   true,   "exceeded file size limit");
98   AddSignal(26,     "SIGVTALRM",    false,    false,  false,  "virtual time alarm");
99   AddSignal(27,     "SIGPROF",      false,    false,  false,  "profiling time alarm");
100   AddSignal(28,     "SIGWINCH",     false,    false,  false,  "window size changes");
101   AddSignal(29,     "SIGINFO",      false,    true,   true,   "information request");
102   AddSignal(30,     "SIGUSR1",      false,    true,   true,   "user defined signal 1");
103   AddSignal(31,     "SIGUSR2",      false,    true,   true,   "user defined signal 2");
104   // clang-format on
105 }
106 
107 void UnixSignals::AddSignal(int signo, const char *name, bool default_suppress,
108                             bool default_stop, bool default_notify,
109                             const char *description, const char *alias) {
110   Signal new_signal(name, default_suppress, default_stop, default_notify,
111                     description, alias);
112   m_signals.insert(std::make_pair(signo, new_signal));
113   ++m_version;
114 }
115 
116 void UnixSignals::AddSignalCode(int signo, int code,
117                                 const llvm::StringLiteral description,
118                                 SignalCodePrintOption print_option) {
119   collection::iterator signal = m_signals.find(signo);
120   assert(signal != m_signals.end() &&
121          "Tried to add code to signal that does not exist.");
122   signal->second.m_codes.insert(
123       std::pair{code, SignalCode{description, print_option}});
124   ++m_version;
125 }
126 
127 void UnixSignals::RemoveSignal(int signo) {
128   collection::iterator pos = m_signals.find(signo);
129   if (pos != m_signals.end())
130     m_signals.erase(pos);
131   ++m_version;
132 }
133 
134 const char *UnixSignals::GetSignalAsCString(int signo) const {
135   collection::const_iterator pos = m_signals.find(signo);
136   if (pos == m_signals.end())
137     return nullptr;
138   else
139     return pos->second.m_name.GetCString();
140 }
141 
142 std::string
143 UnixSignals::GetSignalDescription(int32_t signo, std::optional<int32_t> code,
144                                   std::optional<lldb::addr_t> addr,
145                                   std::optional<lldb::addr_t> lower,
146                                   std::optional<lldb::addr_t> upper) const {
147   std::string str;
148 
149   collection::const_iterator pos = m_signals.find(signo);
150   if (pos != m_signals.end()) {
151     str = pos->second.m_name.GetCString();
152 
153     if (code) {
154       std::map<int32_t, SignalCode>::const_iterator cpos =
155           pos->second.m_codes.find(*code);
156       if (cpos != pos->second.m_codes.end()) {
157         const SignalCode &sc = cpos->second;
158         str += ": ";
159         if (sc.m_print_option != SignalCodePrintOption::Bounds)
160           str += sc.m_description.str();
161 
162         std::stringstream strm;
163         switch (sc.m_print_option) {
164         case SignalCodePrintOption::None:
165           break;
166         case SignalCodePrintOption::Address:
167           if (addr)
168             strm << " (fault address: 0x" << std::hex << *addr << ")";
169           break;
170         case SignalCodePrintOption::Bounds:
171           if (lower && upper && addr) {
172             if ((unsigned long)(*addr) < *lower)
173               strm << "lower bound violation ";
174             else
175               strm << "upper bound violation ";
176 
177             strm << "(fault address: 0x" << std::hex << *addr;
178             strm << ", lower bound: 0x" << std::hex << *lower;
179             strm << ", upper bound: 0x" << std::hex << *upper;
180             strm << ")";
181           } else
182             strm << sc.m_description.str();
183 
184           break;
185         }
186         str += strm.str();
187       }
188     }
189   }
190 
191   return str;
192 }
193 
194 bool UnixSignals::SignalIsValid(int32_t signo) const {
195   return m_signals.find(signo) != m_signals.end();
196 }
197 
198 llvm::StringRef UnixSignals::GetShortName(llvm::StringRef name) const {
199   return name.substr(3); // Remove "SIG" from name
200 }
201 
202 int32_t UnixSignals::GetSignalNumberFromName(const char *name) const {
203   ConstString const_name(name);
204 
205   collection::const_iterator pos, end = m_signals.end();
206   for (pos = m_signals.begin(); pos != end; pos++) {
207     if ((const_name == pos->second.m_name) ||
208         (const_name == pos->second.m_alias) ||
209         (const_name == GetShortName(pos->second.m_name)) ||
210         (const_name == GetShortName(pos->second.m_alias)))
211       return pos->first;
212   }
213 
214   int32_t signo;
215   if (llvm::to_integer(name, signo))
216     return signo;
217   return LLDB_INVALID_SIGNAL_NUMBER;
218 }
219 
220 int32_t UnixSignals::GetFirstSignalNumber() const {
221   if (m_signals.empty())
222     return LLDB_INVALID_SIGNAL_NUMBER;
223 
224   return (*m_signals.begin()).first;
225 }
226 
227 int32_t UnixSignals::GetNextSignalNumber(int32_t current_signal) const {
228   collection::const_iterator pos = m_signals.find(current_signal);
229   collection::const_iterator end = m_signals.end();
230   if (pos == end)
231     return LLDB_INVALID_SIGNAL_NUMBER;
232   else {
233     pos++;
234     if (pos == end)
235       return LLDB_INVALID_SIGNAL_NUMBER;
236     else
237       return pos->first;
238   }
239 }
240 
241 const char *UnixSignals::GetSignalInfo(int32_t signo, bool &should_suppress,
242                                        bool &should_stop,
243                                        bool &should_notify) const {
244   collection::const_iterator pos = m_signals.find(signo);
245   if (pos == m_signals.end())
246     return nullptr;
247   else {
248     const Signal &signal = pos->second;
249     should_suppress = signal.m_suppress;
250     should_stop = signal.m_stop;
251     should_notify = signal.m_notify;
252     return signal.m_name.AsCString("");
253   }
254 }
255 
256 bool UnixSignals::GetShouldSuppress(int signo) const {
257   collection::const_iterator pos = m_signals.find(signo);
258   if (pos != m_signals.end())
259     return pos->second.m_suppress;
260   return false;
261 }
262 
263 bool UnixSignals::SetShouldSuppress(int signo, bool value) {
264   collection::iterator pos = m_signals.find(signo);
265   if (pos != m_signals.end()) {
266     pos->second.m_suppress = value;
267     ++m_version;
268     return true;
269   }
270   return false;
271 }
272 
273 bool UnixSignals::SetShouldSuppress(const char *signal_name, bool value) {
274   const int32_t signo = GetSignalNumberFromName(signal_name);
275   if (signo != LLDB_INVALID_SIGNAL_NUMBER)
276     return SetShouldSuppress(signo, value);
277   return false;
278 }
279 
280 bool UnixSignals::GetShouldStop(int signo) const {
281   collection::const_iterator pos = m_signals.find(signo);
282   if (pos != m_signals.end())
283     return pos->second.m_stop;
284   return false;
285 }
286 
287 bool UnixSignals::SetShouldStop(int signo, bool value) {
288   collection::iterator pos = m_signals.find(signo);
289   if (pos != m_signals.end()) {
290     pos->second.m_stop = value;
291     ++m_version;
292     return true;
293   }
294   return false;
295 }
296 
297 bool UnixSignals::SetShouldStop(const char *signal_name, bool value) {
298   const int32_t signo = GetSignalNumberFromName(signal_name);
299   if (signo != LLDB_INVALID_SIGNAL_NUMBER)
300     return SetShouldStop(signo, value);
301   return false;
302 }
303 
304 bool UnixSignals::GetShouldNotify(int signo) const {
305   collection::const_iterator pos = m_signals.find(signo);
306   if (pos != m_signals.end())
307     return pos->second.m_notify;
308   return false;
309 }
310 
311 bool UnixSignals::SetShouldNotify(int signo, bool value) {
312   collection::iterator pos = m_signals.find(signo);
313   if (pos != m_signals.end()) {
314     pos->second.m_notify = value;
315     ++m_version;
316     return true;
317   }
318   return false;
319 }
320 
321 bool UnixSignals::SetShouldNotify(const char *signal_name, bool value) {
322   const int32_t signo = GetSignalNumberFromName(signal_name);
323   if (signo != LLDB_INVALID_SIGNAL_NUMBER)
324     return SetShouldNotify(signo, value);
325   return false;
326 }
327 
328 int32_t UnixSignals::GetNumSignals() const { return m_signals.size(); }
329 
330 int32_t UnixSignals::GetSignalAtIndex(int32_t index) const {
331   if (index < 0 || m_signals.size() <= static_cast<size_t>(index))
332     return LLDB_INVALID_SIGNAL_NUMBER;
333   auto it = m_signals.begin();
334   std::advance(it, index);
335   return it->first;
336 }
337 
338 uint64_t UnixSignals::GetVersion() const { return m_version; }
339 
340 std::vector<int32_t>
341 UnixSignals::GetFilteredSignals(std::optional<bool> should_suppress,
342                                 std::optional<bool> should_stop,
343                                 std::optional<bool> should_notify) {
344   std::vector<int32_t> result;
345   for (int32_t signo = GetFirstSignalNumber();
346        signo != LLDB_INVALID_SIGNAL_NUMBER;
347        signo = GetNextSignalNumber(signo)) {
348 
349     bool signal_suppress = false;
350     bool signal_stop = false;
351     bool signal_notify = false;
352     GetSignalInfo(signo, signal_suppress, signal_stop, signal_notify);
353 
354     // If any of filtering conditions are not met, we move on to the next
355     // signal.
356     if (should_suppress && signal_suppress != *should_suppress)
357       continue;
358 
359     if (should_stop && signal_stop != *should_stop)
360       continue;
361 
362     if (should_notify && signal_notify != *should_notify)
363       continue;
364 
365     result.push_back(signo);
366   }
367 
368   return result;
369 }
370 
371 void UnixSignals::IncrementSignalHitCount(int signo) {
372   collection::iterator pos = m_signals.find(signo);
373   if (pos != m_signals.end())
374     pos->second.m_hit_count += 1;
375 }
376 
377 json::Value UnixSignals::GetHitCountStatistics() const {
378   json::Array json_signals;
379   for (const auto &pair: m_signals) {
380     if (pair.second.m_hit_count > 0)
381       json_signals.emplace_back(json::Object{
382         { pair.second.m_name.GetCString(), pair.second.m_hit_count }
383       });
384   }
385   return std::move(json_signals);
386 }
387 
388 void UnixSignals::Signal::Reset(bool reset_stop, bool reset_notify,
389                                 bool reset_suppress) {
390   if (reset_stop)
391     m_stop = m_default_stop;
392   if (reset_notify)
393     m_notify = m_default_notify;
394   if (reset_suppress)
395     m_suppress = m_default_suppress;
396 }
397 
398 bool UnixSignals::ResetSignal(int32_t signo, bool reset_stop,
399                                  bool reset_notify, bool reset_suppress) {
400     auto elem = m_signals.find(signo);
401     if (elem == m_signals.end())
402       return false;
403     (*elem).second.Reset(reset_stop, reset_notify, reset_suppress);
404     return true;
405 }
406 
407