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29 
30 // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
31 
32 // module.cc: Implement google_breakpad::Module.  See module.h.
33 
34 #include "common/module.h"
35 
36 #include <assert.h>
37 #include <errno.h>
38 #include <stdio.h>
39 #include <string.h>
40 
41 #include <iostream>
42 #include <utility>
43 
44 namespace google_breakpad {
45 
46 using std::dec;
47 using std::hex;
48 
49 
Module(const string & name,const string & os,const string & architecture,const string & id,const string & code_id)50 Module::Module(const string &name, const string &os,
51                const string &architecture, const string &id,
52                const string &code_id /* = "" */) :
53     name_(name),
54     os_(os),
55     architecture_(architecture),
56     id_(id),
57     code_id_(code_id),
58     load_address_(0) { }
59 
~Module()60 Module::~Module() {
61   for (FileByNameMap::iterator it = files_.begin(); it != files_.end(); ++it)
62     delete it->second;
63   for (FunctionSet::iterator it = functions_.begin();
64        it != functions_.end(); ++it) {
65     delete *it;
66   }
67   for (vector<StackFrameEntry *>::iterator it = stack_frame_entries_.begin();
68        it != stack_frame_entries_.end(); ++it) {
69     delete *it;
70   }
71   for (ExternSet::iterator it = externs_.begin(); it != externs_.end(); ++it)
72     delete *it;
73 }
74 
SetLoadAddress(Address address)75 void Module::SetLoadAddress(Address address) {
76   load_address_ = address;
77 }
78 
SetAddressRanges(const vector<Range> & ranges)79 void Module::SetAddressRanges(const vector<Range>& ranges) {
80   address_ranges_ = ranges;
81 }
82 
AddFunction(Function * function)83 void Module::AddFunction(Function *function) {
84   // FUNC lines must not hold an empty name, so catch the problem early if
85   // callers try to add one.
86   assert(!function->name.empty());
87 
88   if (!AddressIsInModule(function->address)) {
89     return;
90   }
91 
92   // FUNCs are better than PUBLICs as they come with sizes, so remove an extern
93   // with the same address if present.
94   Extern ext(function->address);
95   ExternSet::iterator it_ext = externs_.find(&ext);
96   if (it_ext == externs_.end() &&
97       architecture_ == "arm" &&
98       (function->address & 0x1) == 0) {
99     // ARM THUMB functions have bit 0 set. ARM64 does not have THUMB.
100     Extern arm_thumb_ext(function->address | 0x1);
101     it_ext = externs_.find(&arm_thumb_ext);
102   }
103   if (it_ext != externs_.end()) {
104     delete *it_ext;
105     externs_.erase(it_ext);
106   }
107 #if _DEBUG
108   {
109     // There should be no other PUBLIC symbols that overlap with the function.
110     for (const Range& range : function->ranges) {
111       Extern debug_ext(range.address);
112       ExternSet::iterator it_debug = externs_.lower_bound(&ext);
113       assert(it_debug == externs_.end() ||
114              (*it_debug)->address >= range.address + range.size);
115     }
116   }
117 #endif
118 
119   std::pair<FunctionSet::iterator,bool> ret = functions_.insert(function);
120   if (!ret.second && (*ret.first != function)) {
121     // Free the duplicate that was not inserted because this Module
122     // now owns it.
123     delete function;
124   }
125 }
126 
AddFunctions(vector<Function * >::iterator begin,vector<Function * >::iterator end)127 void Module::AddFunctions(vector<Function *>::iterator begin,
128                           vector<Function *>::iterator end) {
129   for (vector<Function *>::iterator it = begin; it != end; ++it)
130     AddFunction(*it);
131 }
132 
AddStackFrameEntry(StackFrameEntry * stack_frame_entry)133 void Module::AddStackFrameEntry(StackFrameEntry *stack_frame_entry) {
134   if (!AddressIsInModule(stack_frame_entry->address)) {
135     return;
136   }
137 
138   stack_frame_entries_.push_back(stack_frame_entry);
139 }
140 
AddExtern(Extern * ext)141 void Module::AddExtern(Extern *ext) {
142   if (!AddressIsInModule(ext->address)) {
143     return;
144   }
145 
146   std::pair<ExternSet::iterator,bool> ret = externs_.insert(ext);
147   if (!ret.second) {
148     // Free the duplicate that was not inserted because this Module
149     // now owns it.
150     delete ext;
151   }
152 }
153 
GetFunctions(vector<Function * > * vec,vector<Function * >::iterator i)154 void Module::GetFunctions(vector<Function *> *vec,
155                           vector<Function *>::iterator i) {
156   vec->insert(i, functions_.begin(), functions_.end());
157 }
158 
GetExterns(vector<Extern * > * vec,vector<Extern * >::iterator i)159 void Module::GetExterns(vector<Extern *> *vec,
160                         vector<Extern *>::iterator i) {
161   vec->insert(i, externs_.begin(), externs_.end());
162 }
163 
FindFile(const string & name)164 Module::File *Module::FindFile(const string &name) {
165   // A tricky bit here.  The key of each map entry needs to be a
166   // pointer to the entry's File's name string.  This means that we
167   // can't do the initial lookup with any operation that would create
168   // an empty entry for us if the name isn't found (like, say,
169   // operator[] or insert do), because such a created entry's key will
170   // be a pointer the string passed as our argument.  Since the key of
171   // a map's value type is const, we can't fix it up once we've
172   // created our file.  lower_bound does the lookup without doing an
173   // insertion, and returns a good hint iterator to pass to insert.
174   // Our "destiny" is where we belong, whether we're there or not now.
175   FileByNameMap::iterator destiny = files_.lower_bound(&name);
176   if (destiny == files_.end()
177       || *destiny->first != name) {  // Repeated string comparison, boo hoo.
178     File *file = new File(name);
179     file->source_id = -1;
180     destiny = files_.insert(destiny,
181                             FileByNameMap::value_type(&file->name, file));
182   }
183   return destiny->second;
184 }
185 
FindFile(const char * name)186 Module::File *Module::FindFile(const char *name) {
187   string name_string = name;
188   return FindFile(name_string);
189 }
190 
FindExistingFile(const string & name)191 Module::File *Module::FindExistingFile(const string &name) {
192   FileByNameMap::iterator it = files_.find(&name);
193   return (it == files_.end()) ? NULL : it->second;
194 }
195 
GetFiles(vector<File * > * vec)196 void Module::GetFiles(vector<File *> *vec) {
197   vec->clear();
198   for (FileByNameMap::iterator it = files_.begin(); it != files_.end(); ++it)
199     vec->push_back(it->second);
200 }
201 
GetStackFrameEntries(vector<StackFrameEntry * > * vec) const202 void Module::GetStackFrameEntries(vector<StackFrameEntry *> *vec) const {
203   *vec = stack_frame_entries_;
204 }
205 
AssignSourceIds()206 void Module::AssignSourceIds() {
207   // First, give every source file an id of -1.
208   for (FileByNameMap::iterator file_it = files_.begin();
209        file_it != files_.end(); ++file_it) {
210     file_it->second->source_id = -1;
211   }
212 
213   // Next, mark all files actually cited by our functions' line number
214   // info, by setting each one's source id to zero.
215   for (FunctionSet::const_iterator func_it = functions_.begin();
216        func_it != functions_.end(); ++func_it) {
217     Function *func = *func_it;
218     for (vector<Line>::iterator line_it = func->lines.begin();
219          line_it != func->lines.end(); ++line_it)
220       line_it->file->source_id = 0;
221   }
222 
223   // Finally, assign source ids to those files that have been marked.
224   // We could have just assigned source id numbers while traversing
225   // the line numbers, but doing it this way numbers the files in
226   // lexicographical order by name, which is neat.
227   int next_source_id = 0;
228   for (FileByNameMap::iterator file_it = files_.begin();
229        file_it != files_.end(); ++file_it) {
230     if (!file_it->second->source_id)
231       file_it->second->source_id = next_source_id++;
232   }
233 }
234 
ReportError()235 bool Module::ReportError() {
236   fprintf(stderr, "error writing symbol file: %s\n",
237           strerror(errno));
238   return false;
239 }
240 
WriteRuleMap(const RuleMap & rule_map,std::ostream & stream)241 bool Module::WriteRuleMap(const RuleMap &rule_map, std::ostream &stream) {
242   for (RuleMap::const_iterator it = rule_map.begin();
243        it != rule_map.end(); ++it) {
244     if (it != rule_map.begin())
245       stream << ' ';
246     stream << it->first << ": " << it->second;
247   }
248   return stream.good();
249 }
250 
AddressIsInModule(Address address) const251 bool Module::AddressIsInModule(Address address) const {
252   if (address_ranges_.empty()) {
253     return true;
254   }
255   for (const auto& segment : address_ranges_) {
256     if (address >= segment.address &&
257         address < segment.address + segment.size) {
258       return true;
259     }
260   }
261   return false;
262 }
263 
Write(std::ostream & stream,SymbolData symbol_data)264 bool Module::Write(std::ostream &stream, SymbolData symbol_data) {
265   stream << "MODULE " << os_ << " " << architecture_ << " "
266          << id_ << " " << name_ << "\n";
267   if (!stream.good())
268     return ReportError();
269 
270   if (!code_id_.empty()) {
271     stream << "INFO CODE_ID " << code_id_ << "\n";
272   }
273 
274   if (symbol_data != ONLY_CFI) {
275     AssignSourceIds();
276 
277     // Write out files.
278     for (FileByNameMap::iterator file_it = files_.begin();
279          file_it != files_.end(); ++file_it) {
280       File *file = file_it->second;
281       if (file->source_id >= 0) {
282         stream << "FILE " << file->source_id << " " <<  file->name << "\n";
283         if (!stream.good())
284           return ReportError();
285       }
286     }
287 
288     // Write out functions and their lines.
289     for (FunctionSet::const_iterator func_it = functions_.begin();
290          func_it != functions_.end(); ++func_it) {
291       Function *func = *func_it;
292       vector<Line>::iterator line_it = func->lines.begin();
293       for (auto range_it = func->ranges.cbegin();
294            range_it != func->ranges.cend(); ++range_it) {
295         stream << "FUNC " << hex
296                << (range_it->address - load_address_) << " "
297                << range_it->size << " "
298                << func->parameter_size << " "
299                << func->name << dec << "\n";
300 
301         if (!stream.good())
302           return ReportError();
303 
304         while ((line_it != func->lines.end()) &&
305                (line_it->address >= range_it->address) &&
306                (line_it->address < (range_it->address + range_it->size))) {
307           stream << hex
308                  << (line_it->address - load_address_) << " "
309                  << line_it->size << " "
310                  << dec
311                  << line_it->number << " "
312                  << line_it->file->source_id << "\n";
313 
314           if (!stream.good())
315             return ReportError();
316 
317           ++line_it;
318         }
319       }
320     }
321 
322     // Write out 'PUBLIC' records.
323     for (ExternSet::const_iterator extern_it = externs_.begin();
324          extern_it != externs_.end(); ++extern_it) {
325       Extern *ext = *extern_it;
326       stream << "PUBLIC " << hex
327              << (ext->address - load_address_) << " 0 "
328              << ext->name << dec << "\n";
329     }
330   }
331 
332   if (symbol_data != NO_CFI) {
333     // Write out 'STACK CFI INIT' and 'STACK CFI' records.
334     vector<StackFrameEntry *>::const_iterator frame_it;
335     for (frame_it = stack_frame_entries_.begin();
336          frame_it != stack_frame_entries_.end(); ++frame_it) {
337       StackFrameEntry *entry = *frame_it;
338       stream << "STACK CFI INIT " << hex
339              << (entry->address - load_address_) << " "
340              << entry->size << " " << dec;
341       if (!stream.good()
342           || !WriteRuleMap(entry->initial_rules, stream))
343         return ReportError();
344 
345       stream << "\n";
346 
347       // Write out this entry's delta rules as 'STACK CFI' records.
348       for (RuleChangeMap::const_iterator delta_it = entry->rule_changes.begin();
349            delta_it != entry->rule_changes.end(); ++delta_it) {
350         stream << "STACK CFI " << hex
351                << (delta_it->first - load_address_) << " " << dec;
352         if (!stream.good()
353             || !WriteRuleMap(delta_it->second, stream))
354           return ReportError();
355 
356         stream << "\n";
357       }
358     }
359   }
360 
361   return true;
362 }
363 
364 }  // namespace google_breakpad
365