1 // Copyright (c) 2010, Google Inc.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
8 //     * Redistributions of source code must retain the above copyright
9 // notice, this list of conditions and the following disclaimer.
10 //     * Redistributions in binary form must reproduce the above
11 // copyright notice, this list of conditions and the following disclaimer
12 // in the documentation and/or other materials provided with the
13 // distribution.
14 //     * Neither the name of Google Inc. nor the names of its
15 // contributors may be used to endorse or promote products derived from
16 // this software without specific prior written permission.
17 //
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 
30 // This code writes out minidump files:
31 //   http://msdn.microsoft.com/en-us/library/ms680378(VS.85,loband).aspx
32 //
33 // Minidumps are a Microsoft format which Breakpad uses for recording crash
34 // dumps. This code has to run in a compromised environment (the address space
35 // may have received SIGSEGV), thus the following rules apply:
36 //   * You may not enter the dynamic linker. This means that we cannot call
37 //     any symbols in a shared library (inc libc). Because of this we replace
38 //     libc functions in linux_libc_support.h.
39 //   * You may not call syscalls via the libc wrappers. This rule is a subset
40 //     of the first rule but it bears repeating. We have direct wrappers
41 //     around the system calls in linux_syscall_support.h.
42 //   * You may not malloc. There's an alternative allocator in memory.h and
43 //     a canonical instance in the LinuxDumper object. We use the placement
44 //     new form to allocate objects and we don't delete them.
45 
46 #include "client/linux/handler/minidump_descriptor.h"
47 #include "client/linux/minidump_writer/minidump_writer.h"
48 #include "client/minidump_file_writer-inl.h"
49 
50 #include <ctype.h>
51 #include <errno.h>
52 #include <fcntl.h>
53 #include <link.h>
54 #include <stdio.h>
55 #if defined(__ANDROID__)
56 #include <sys/system_properties.h>
57 #endif
58 #include <sys/types.h>
59 #include <sys/ucontext.h>
60 #include <sys/user.h>
61 #include <sys/utsname.h>
62 #include <time.h>
63 #include <unistd.h>
64 
65 #include <algorithm>
66 
67 #include "client/linux/dump_writer_common/seccomp_unwinder.h"
68 #include "client/linux/dump_writer_common/thread_info.h"
69 #include "client/linux/dump_writer_common/ucontext_reader.h"
70 #include "client/linux/handler/exception_handler.h"
71 #include "client/linux/minidump_writer/cpu_set.h"
72 #include "client/linux/minidump_writer/line_reader.h"
73 #include "client/linux/minidump_writer/linux_dumper.h"
74 #include "client/linux/minidump_writer/linux_ptrace_dumper.h"
75 #include "client/linux/minidump_writer/proc_cpuinfo_reader.h"
76 #include "client/minidump_file_writer.h"
77 #include "common/linux/linux_libc_support.h"
78 #include "common/minidump_type_helper.h"
79 #include "google_breakpad/common/minidump_format.h"
80 #include "third_party/lss/linux_syscall_support.h"
81 
82 namespace {
83 
84 using google_breakpad::AppMemoryList;
85 using google_breakpad::ExceptionHandler;
86 using google_breakpad::CpuSet;
87 using google_breakpad::LineReader;
88 using google_breakpad::LinuxDumper;
89 using google_breakpad::LinuxPtraceDumper;
90 using google_breakpad::MDTypeHelper;
91 using google_breakpad::MappingEntry;
92 using google_breakpad::MappingInfo;
93 using google_breakpad::MappingList;
94 using google_breakpad::MinidumpFileWriter;
95 using google_breakpad::PageAllocator;
96 using google_breakpad::ProcCpuInfoReader;
97 using google_breakpad::RawContextCPU;
98 using google_breakpad::SeccompUnwinder;
99 using google_breakpad::ThreadInfo;
100 using google_breakpad::TypedMDRVA;
101 using google_breakpad::UContextReader;
102 using google_breakpad::UntypedMDRVA;
103 using google_breakpad::wasteful_vector;
104 
105 typedef MDTypeHelper<sizeof(void*)>::MDRawDebug MDRawDebug;
106 typedef MDTypeHelper<sizeof(void*)>::MDRawLinkMap MDRawLinkMap;
107 
108 class MinidumpWriter {
109  public:
110   // The following kLimit* constants are for when minidump_size_limit_ is set
111   // and the minidump size might exceed it.
112   //
113   // Estimate for how big each thread's stack will be (in bytes).
114   static const unsigned kLimitAverageThreadStackLength = 8 * 1024;
115   // Number of threads whose stack size we don't want to limit.  These base
116   // threads will simply be the first N threads returned by the dumper (although
117   // the crashing thread will never be limited).  Threads beyond this count are
118   // the extra threads.
119   static const unsigned kLimitBaseThreadCount = 20;
120   // Maximum stack size to dump for any extra thread (in bytes).
121   static const unsigned kLimitMaxExtraThreadStackLen = 2 * 1024;
122   // Make sure this number of additional bytes can fit in the minidump
123   // (exclude the stack data).
124   static const unsigned kLimitMinidumpFudgeFactor = 64 * 1024;
125 
MinidumpWriter(const char * minidump_path,int minidump_fd,const ExceptionHandler::CrashContext * context,const MappingList & mappings,const AppMemoryList & appmem,LinuxDumper * dumper)126   MinidumpWriter(const char* minidump_path,
127                  int minidump_fd,
128                  const ExceptionHandler::CrashContext* context,
129                  const MappingList& mappings,
130                  const AppMemoryList& appmem,
131                  LinuxDumper* dumper)
132       : fd_(minidump_fd),
133         path_(minidump_path),
134         ucontext_(context ? &context->context : NULL),
135 #if !defined(__ARM_EABI__) && !defined(__mips__)
136         float_state_(context ? &context->float_state : NULL),
137 #endif
138         dumper_(dumper),
139         minidump_size_limit_(-1),
140         memory_blocks_(dumper_->allocator()),
141         mapping_list_(mappings),
142         app_memory_list_(appmem) {
143     // Assert there should be either a valid fd or a valid path, not both.
144     assert(fd_ != -1 || minidump_path);
145     assert(fd_ == -1 || !minidump_path);
146   }
147 
Init()148   bool Init() {
149     if (!dumper_->Init())
150       return false;
151 
152     if (fd_ != -1)
153       minidump_writer_.SetFile(fd_);
154     else if (!minidump_writer_.Open(path_))
155       return false;
156 
157     return dumper_->ThreadsSuspend();
158   }
159 
~MinidumpWriter()160   ~MinidumpWriter() {
161     // Don't close the file descriptor when it's been provided explicitly.
162     // Callers might still need to use it.
163     if (fd_ == -1)
164       minidump_writer_.Close();
165     dumper_->ThreadsResume();
166   }
167 
Dump()168   bool Dump() {
169     // A minidump file contains a number of tagged streams. This is the number
170     // of stream which we write.
171     unsigned kNumWriters = 13;
172 
173     TypedMDRVA<MDRawHeader> header(&minidump_writer_);
174     TypedMDRVA<MDRawDirectory> dir(&minidump_writer_);
175     if (!header.Allocate())
176       return false;
177     if (!dir.AllocateArray(kNumWriters))
178       return false;
179     my_memset(header.get(), 0, sizeof(MDRawHeader));
180 
181     header.get()->signature = MD_HEADER_SIGNATURE;
182     header.get()->version = MD_HEADER_VERSION;
183     header.get()->time_date_stamp = time(NULL);
184     header.get()->stream_count = kNumWriters;
185     header.get()->stream_directory_rva = dir.position();
186 
187     unsigned dir_index = 0;
188     MDRawDirectory dirent;
189 
190     if (!WriteThreadListStream(&dirent))
191       return false;
192     dir.CopyIndex(dir_index++, &dirent);
193 
194     if (!WriteMappings(&dirent))
195       return false;
196     dir.CopyIndex(dir_index++, &dirent);
197 
198     if (!WriteAppMemory())
199       return false;
200 
201     if (!WriteMemoryListStream(&dirent))
202       return false;
203     dir.CopyIndex(dir_index++, &dirent);
204 
205     if (!WriteExceptionStream(&dirent))
206       return false;
207     dir.CopyIndex(dir_index++, &dirent);
208 
209     if (!WriteSystemInfoStream(&dirent))
210       return false;
211     dir.CopyIndex(dir_index++, &dirent);
212 
213     dirent.stream_type = MD_LINUX_CPU_INFO;
214     if (!WriteFile(&dirent.location, "/proc/cpuinfo"))
215       NullifyDirectoryEntry(&dirent);
216     dir.CopyIndex(dir_index++, &dirent);
217 
218     dirent.stream_type = MD_LINUX_PROC_STATUS;
219     if (!WriteProcFile(&dirent.location, GetCrashThread(), "status"))
220       NullifyDirectoryEntry(&dirent);
221     dir.CopyIndex(dir_index++, &dirent);
222 
223     dirent.stream_type = MD_LINUX_LSB_RELEASE;
224     if (!WriteFile(&dirent.location, "/etc/lsb-release"))
225       NullifyDirectoryEntry(&dirent);
226     dir.CopyIndex(dir_index++, &dirent);
227 
228     dirent.stream_type = MD_LINUX_CMD_LINE;
229     if (!WriteProcFile(&dirent.location, GetCrashThread(), "cmdline"))
230       NullifyDirectoryEntry(&dirent);
231     dir.CopyIndex(dir_index++, &dirent);
232 
233     dirent.stream_type = MD_LINUX_ENVIRON;
234     if (!WriteProcFile(&dirent.location, GetCrashThread(), "environ"))
235       NullifyDirectoryEntry(&dirent);
236     dir.CopyIndex(dir_index++, &dirent);
237 
238     dirent.stream_type = MD_LINUX_AUXV;
239     if (!WriteProcFile(&dirent.location, GetCrashThread(), "auxv"))
240       NullifyDirectoryEntry(&dirent);
241     dir.CopyIndex(dir_index++, &dirent);
242 
243     dirent.stream_type = MD_LINUX_MAPS;
244     if (!WriteProcFile(&dirent.location, GetCrashThread(), "maps"))
245       NullifyDirectoryEntry(&dirent);
246     dir.CopyIndex(dir_index++, &dirent);
247 
248     dirent.stream_type = MD_LINUX_DSO_DEBUG;
249     if (!WriteDSODebugStream(&dirent))
250       NullifyDirectoryEntry(&dirent);
251     dir.CopyIndex(dir_index++, &dirent);
252 
253     // If you add more directory entries, don't forget to update kNumWriters,
254     // above.
255 
256     dumper_->ThreadsResume();
257     return true;
258   }
259 
FillThreadStack(MDRawThread * thread,uintptr_t stack_pointer,int max_stack_len,uint8_t ** stack_copy)260   bool FillThreadStack(MDRawThread* thread, uintptr_t stack_pointer,
261                        int max_stack_len, uint8_t** stack_copy) {
262     *stack_copy = NULL;
263     const void* stack;
264     size_t stack_len;
265     if (dumper_->GetStackInfo(&stack, &stack_len, stack_pointer)) {
266       UntypedMDRVA memory(&minidump_writer_);
267       if (max_stack_len >= 0 &&
268           stack_len > static_cast<unsigned int>(max_stack_len)) {
269         stack_len = max_stack_len;
270       }
271       if (!memory.Allocate(stack_len))
272         return false;
273       *stack_copy = reinterpret_cast<uint8_t*>(Alloc(stack_len));
274       dumper_->CopyFromProcess(*stack_copy, thread->thread_id, stack,
275                                stack_len);
276       memory.Copy(*stack_copy, stack_len);
277       thread->stack.start_of_memory_range =
278           reinterpret_cast<uintptr_t>(stack);
279       thread->stack.memory = memory.location();
280       memory_blocks_.push_back(thread->stack);
281     } else {
282       thread->stack.start_of_memory_range = stack_pointer;
283       thread->stack.memory.data_size = 0;
284       thread->stack.memory.rva = minidump_writer_.position();
285     }
286     return true;
287   }
288 
289   // Write information about the threads.
WriteThreadListStream(MDRawDirectory * dirent)290   bool WriteThreadListStream(MDRawDirectory* dirent) {
291     const unsigned num_threads = dumper_->threads().size();
292 
293     TypedMDRVA<uint32_t> list(&minidump_writer_);
294     if (!list.AllocateObjectAndArray(num_threads, sizeof(MDRawThread)))
295       return false;
296 
297     dirent->stream_type = MD_THREAD_LIST_STREAM;
298     dirent->location = list.location();
299 
300     *list.get() = num_threads;
301 
302     // If there's a minidump size limit, check if it might be exceeded.  Since
303     // most of the space is filled with stack data, just check against that.
304     // If this expects to exceed the limit, set extra_thread_stack_len such
305     // that any thread beyond the first kLimitBaseThreadCount threads will
306     // have only kLimitMaxExtraThreadStackLen bytes dumped.
307     int extra_thread_stack_len = -1;  // default to no maximum
308     if (minidump_size_limit_ >= 0) {
309       const unsigned estimated_total_stack_size = num_threads *
310           kLimitAverageThreadStackLength;
311       const off_t estimated_minidump_size = minidump_writer_.position() +
312           estimated_total_stack_size + kLimitMinidumpFudgeFactor;
313       if (estimated_minidump_size > minidump_size_limit_)
314         extra_thread_stack_len = kLimitMaxExtraThreadStackLen;
315     }
316 
317     for (unsigned i = 0; i < num_threads; ++i) {
318       MDRawThread thread;
319       my_memset(&thread, 0, sizeof(thread));
320       thread.thread_id = dumper_->threads()[i];
321 
322       // We have a different source of information for the crashing thread. If
323       // we used the actual state of the thread we would find it running in the
324       // signal handler with the alternative stack, which would be deeply
325       // unhelpful.
326       if (static_cast<pid_t>(thread.thread_id) == GetCrashThread() &&
327           ucontext_ &&
328           !dumper_->IsPostMortem()) {
329         uint8_t* stack_copy;
330         const uintptr_t stack_ptr = UContextReader::GetStackPointer(ucontext_);
331         if (!FillThreadStack(&thread, stack_ptr, -1, &stack_copy))
332           return false;
333 
334         // Copy 256 bytes around crashing instruction pointer to minidump.
335         const size_t kIPMemorySize = 256;
336         uint64_t ip = UContextReader::GetInstructionPointer(ucontext_);
337         // Bound it to the upper and lower bounds of the memory map
338         // it's contained within. If it's not in mapped memory,
339         // don't bother trying to write it.
340         bool ip_is_mapped = false;
341         MDMemoryDescriptor ip_memory_d;
342         for (unsigned j = 0; j < dumper_->mappings().size(); ++j) {
343           const MappingInfo& mapping = *dumper_->mappings()[j];
344           if (ip >= mapping.start_addr &&
345               ip < mapping.start_addr + mapping.size) {
346             ip_is_mapped = true;
347             // Try to get 128 bytes before and after the IP, but
348             // settle for whatever's available.
349             ip_memory_d.start_of_memory_range =
350               std::max(mapping.start_addr,
351                        uintptr_t(ip - (kIPMemorySize / 2)));
352             uintptr_t end_of_range =
353               std::min(uintptr_t(ip + (kIPMemorySize / 2)),
354                        uintptr_t(mapping.start_addr + mapping.size));
355             ip_memory_d.memory.data_size =
356               end_of_range - ip_memory_d.start_of_memory_range;
357             break;
358           }
359         }
360 
361         if (ip_is_mapped) {
362           UntypedMDRVA ip_memory(&minidump_writer_);
363           if (!ip_memory.Allocate(ip_memory_d.memory.data_size))
364             return false;
365           uint8_t* memory_copy =
366               reinterpret_cast<uint8_t*>(Alloc(ip_memory_d.memory.data_size));
367           dumper_->CopyFromProcess(
368               memory_copy,
369               thread.thread_id,
370               reinterpret_cast<void*>(ip_memory_d.start_of_memory_range),
371               ip_memory_d.memory.data_size);
372           ip_memory.Copy(memory_copy, ip_memory_d.memory.data_size);
373           ip_memory_d.memory = ip_memory.location();
374           memory_blocks_.push_back(ip_memory_d);
375         }
376 
377         TypedMDRVA<RawContextCPU> cpu(&minidump_writer_);
378         if (!cpu.Allocate())
379           return false;
380         my_memset(cpu.get(), 0, sizeof(RawContextCPU));
381 #if !defined(__ARM_EABI__) && !defined(__mips__)
382         UContextReader::FillCPUContext(cpu.get(), ucontext_, float_state_);
383 #else
384         UContextReader::FillCPUContext(cpu.get(), ucontext_);
385 #endif
386         if (stack_copy)
387           SeccompUnwinder::PopSeccompStackFrame(cpu.get(), thread, stack_copy);
388         thread.thread_context = cpu.location();
389         crashing_thread_context_ = cpu.location();
390       } else {
391         ThreadInfo info;
392         if (!dumper_->GetThreadInfoByIndex(i, &info))
393           return false;
394 
395         uint8_t* stack_copy;
396         int max_stack_len = -1;  // default to no maximum for this thread
397         if (minidump_size_limit_ >= 0 && i >= kLimitBaseThreadCount)
398           max_stack_len = extra_thread_stack_len;
399         if (!FillThreadStack(&thread, info.stack_pointer, max_stack_len,
400             &stack_copy))
401           return false;
402 
403         TypedMDRVA<RawContextCPU> cpu(&minidump_writer_);
404         if (!cpu.Allocate())
405           return false;
406         my_memset(cpu.get(), 0, sizeof(RawContextCPU));
407         info.FillCPUContext(cpu.get());
408         if (stack_copy)
409           SeccompUnwinder::PopSeccompStackFrame(cpu.get(), thread, stack_copy);
410         thread.thread_context = cpu.location();
411         if (dumper_->threads()[i] == GetCrashThread()) {
412           crashing_thread_context_ = cpu.location();
413           if (!dumper_->IsPostMortem()) {
414             // This is the crashing thread of a live process, but
415             // no context was provided, so set the crash address
416             // while the instruction pointer is already here.
417             dumper_->set_crash_address(info.GetInstructionPointer());
418           }
419         }
420       }
421 
422       list.CopyIndexAfterObject(i, &thread, sizeof(thread));
423     }
424 
425     return true;
426   }
427 
428   // Write application-provided memory regions.
WriteAppMemory()429   bool WriteAppMemory() {
430     for (AppMemoryList::const_iterator iter = app_memory_list_.begin();
431          iter != app_memory_list_.end();
432          ++iter) {
433       uint8_t* data_copy =
434         reinterpret_cast<uint8_t*>(dumper_->allocator()->Alloc(iter->length));
435       dumper_->CopyFromProcess(data_copy, GetCrashThread(), iter->ptr,
436                                iter->length);
437 
438       UntypedMDRVA memory(&minidump_writer_);
439       if (!memory.Allocate(iter->length)) {
440         return false;
441       }
442       memory.Copy(data_copy, iter->length);
443       MDMemoryDescriptor desc;
444       desc.start_of_memory_range = reinterpret_cast<uintptr_t>(iter->ptr);
445       desc.memory = memory.location();
446       memory_blocks_.push_back(desc);
447     }
448 
449     return true;
450   }
451 
ShouldIncludeMapping(const MappingInfo & mapping)452   static bool ShouldIncludeMapping(const MappingInfo& mapping) {
453     if (mapping.name[0] == 0 ||  // only want modules with filenames.
454         // Only want to include one mapping per shared lib.
455         // Avoid filtering executable mappings.
456         (mapping.offset != 0 && !mapping.exec) ||
457         mapping.size < 4096) {  // too small to get a signature for.
458       return false;
459     }
460 
461     return true;
462   }
463 
464   // If there is caller-provided information about this mapping
465   // in the mapping_list_ list, return true. Otherwise, return false.
HaveMappingInfo(const MappingInfo & mapping)466   bool HaveMappingInfo(const MappingInfo& mapping) {
467     for (MappingList::const_iterator iter = mapping_list_.begin();
468          iter != mapping_list_.end();
469          ++iter) {
470       // Ignore any mappings that are wholly contained within
471       // mappings in the mapping_info_ list.
472       if (mapping.start_addr >= iter->first.start_addr &&
473           (mapping.start_addr + mapping.size) <=
474           (iter->first.start_addr + iter->first.size)) {
475         return true;
476       }
477     }
478     return false;
479   }
480 
481   // Write information about the mappings in effect. Because we are using the
482   // minidump format, the information about the mappings is pretty limited.
483   // Because of this, we also include the full, unparsed, /proc/$x/maps file in
484   // another stream in the file.
WriteMappings(MDRawDirectory * dirent)485   bool WriteMappings(MDRawDirectory* dirent) {
486     const unsigned num_mappings = dumper_->mappings().size();
487     unsigned num_output_mappings = mapping_list_.size();
488 
489     for (unsigned i = 0; i < dumper_->mappings().size(); ++i) {
490       const MappingInfo& mapping = *dumper_->mappings()[i];
491       if (ShouldIncludeMapping(mapping) && !HaveMappingInfo(mapping))
492         num_output_mappings++;
493     }
494 
495     TypedMDRVA<uint32_t> list(&minidump_writer_);
496     if (num_output_mappings) {
497       if (!list.AllocateObjectAndArray(num_output_mappings, MD_MODULE_SIZE))
498         return false;
499     } else {
500       // Still create the module list stream, although it will have zero
501       // modules.
502       if (!list.Allocate())
503         return false;
504     }
505 
506     dirent->stream_type = MD_MODULE_LIST_STREAM;
507     dirent->location = list.location();
508     *list.get() = num_output_mappings;
509 
510     // First write all the mappings from the dumper
511     unsigned int j = 0;
512     for (unsigned i = 0; i < num_mappings; ++i) {
513       const MappingInfo& mapping = *dumper_->mappings()[i];
514       if (!ShouldIncludeMapping(mapping) || HaveMappingInfo(mapping))
515         continue;
516 
517       MDRawModule mod;
518       if (!FillRawModule(mapping, true, i, mod, NULL))
519         return false;
520       list.CopyIndexAfterObject(j++, &mod, MD_MODULE_SIZE);
521     }
522     // Next write all the mappings provided by the caller
523     for (MappingList::const_iterator iter = mapping_list_.begin();
524          iter != mapping_list_.end();
525          ++iter) {
526       MDRawModule mod;
527       if (!FillRawModule(iter->first, false, 0, mod, iter->second))
528         return false;
529       list.CopyIndexAfterObject(j++, &mod, MD_MODULE_SIZE);
530     }
531 
532     return true;
533   }
534 
535   // Fill the MDRawModule |mod| with information about the provided
536   // |mapping|. If |identifier| is non-NULL, use it instead of calculating
537   // a file ID from the mapping.
FillRawModule(const MappingInfo & mapping,bool member,unsigned int mapping_id,MDRawModule & mod,const uint8_t * identifier)538   bool FillRawModule(const MappingInfo& mapping,
539                      bool member,
540                      unsigned int mapping_id,
541                      MDRawModule& mod,
542                      const uint8_t* identifier) {
543     my_memset(&mod, 0, MD_MODULE_SIZE);
544 
545     mod.base_of_image = mapping.start_addr;
546     mod.size_of_image = mapping.size;
547 
548     uint8_t cv_buf[MDCVInfoPDB70_minsize + NAME_MAX];
549     uint8_t* cv_ptr = cv_buf;
550 
551     const uint32_t cv_signature = MD_CVINFOPDB70_SIGNATURE;
552     my_memcpy(cv_ptr, &cv_signature, sizeof(cv_signature));
553     cv_ptr += sizeof(cv_signature);
554     uint8_t* signature = cv_ptr;
555     cv_ptr += sizeof(MDGUID);
556     if (identifier) {
557       // GUID was provided by caller.
558       my_memcpy(signature, identifier, sizeof(MDGUID));
559     } else {
560       // Note: ElfFileIdentifierForMapping() can manipulate the |mapping.name|.
561       dumper_->ElfFileIdentifierForMapping(mapping, member,
562                                            mapping_id, signature);
563     }
564     my_memset(cv_ptr, 0, sizeof(uint32_t));  // Set age to 0 on Linux.
565     cv_ptr += sizeof(uint32_t);
566 
567     char file_name[NAME_MAX];
568     char file_path[NAME_MAX];
569     LinuxDumper::GetMappingEffectiveNameAndPath(
570         mapping, file_path, sizeof(file_path), file_name, sizeof(file_name));
571 
572     const size_t file_name_len = my_strlen(file_name);
573     UntypedMDRVA cv(&minidump_writer_);
574     if (!cv.Allocate(MDCVInfoPDB70_minsize + file_name_len + 1))
575       return false;
576 
577     // Write pdb_file_name
578     my_memcpy(cv_ptr, file_name, file_name_len + 1);
579     cv.Copy(cv_buf, MDCVInfoPDB70_minsize + file_name_len + 1);
580 
581     mod.cv_record = cv.location();
582 
583     MDLocationDescriptor ld;
584     if (!minidump_writer_.WriteString(file_path, my_strlen(file_path), &ld))
585       return false;
586     mod.module_name_rva = ld.rva;
587     return true;
588   }
589 
WriteMemoryListStream(MDRawDirectory * dirent)590   bool WriteMemoryListStream(MDRawDirectory* dirent) {
591     TypedMDRVA<uint32_t> list(&minidump_writer_);
592     if (memory_blocks_.size()) {
593       if (!list.AllocateObjectAndArray(memory_blocks_.size(),
594                                        sizeof(MDMemoryDescriptor)))
595         return false;
596     } else {
597       // Still create the memory list stream, although it will have zero
598       // memory blocks.
599       if (!list.Allocate())
600         return false;
601     }
602 
603     dirent->stream_type = MD_MEMORY_LIST_STREAM;
604     dirent->location = list.location();
605 
606     *list.get() = memory_blocks_.size();
607 
608     for (size_t i = 0; i < memory_blocks_.size(); ++i) {
609       list.CopyIndexAfterObject(i, &memory_blocks_[i],
610                                 sizeof(MDMemoryDescriptor));
611     }
612     return true;
613   }
614 
WriteExceptionStream(MDRawDirectory * dirent)615   bool WriteExceptionStream(MDRawDirectory* dirent) {
616     TypedMDRVA<MDRawExceptionStream> exc(&minidump_writer_);
617     if (!exc.Allocate())
618       return false;
619     my_memset(exc.get(), 0, sizeof(MDRawExceptionStream));
620 
621     dirent->stream_type = MD_EXCEPTION_STREAM;
622     dirent->location = exc.location();
623 
624     exc.get()->thread_id = GetCrashThread();
625     exc.get()->exception_record.exception_code = dumper_->crash_signal();
626     exc.get()->exception_record.exception_address = dumper_->crash_address();
627     exc.get()->thread_context = crashing_thread_context_;
628 
629     return true;
630   }
631 
WriteSystemInfoStream(MDRawDirectory * dirent)632   bool WriteSystemInfoStream(MDRawDirectory* dirent) {
633     TypedMDRVA<MDRawSystemInfo> si(&minidump_writer_);
634     if (!si.Allocate())
635       return false;
636     my_memset(si.get(), 0, sizeof(MDRawSystemInfo));
637 
638     dirent->stream_type = MD_SYSTEM_INFO_STREAM;
639     dirent->location = si.location();
640 
641     WriteCPUInformation(si.get());
642     WriteOSInformation(si.get());
643 
644     return true;
645   }
646 
WriteDSODebugStream(MDRawDirectory * dirent)647   bool WriteDSODebugStream(MDRawDirectory* dirent) {
648     ElfW(Phdr)* phdr = reinterpret_cast<ElfW(Phdr) *>(dumper_->auxv()[AT_PHDR]);
649     char* base;
650     int phnum = dumper_->auxv()[AT_PHNUM];
651     if (!phnum || !phdr)
652       return false;
653 
654     // Assume the program base is at the beginning of the same page as the PHDR
655     base = reinterpret_cast<char *>(reinterpret_cast<uintptr_t>(phdr) & ~0xfff);
656 
657     // Search for the program PT_DYNAMIC segment
658     ElfW(Addr) dyn_addr = 0;
659     for (; phnum >= 0; phnum--, phdr++) {
660       ElfW(Phdr) ph;
661       if (!dumper_->CopyFromProcess(&ph, GetCrashThread(), phdr, sizeof(ph)))
662         return false;
663 
664       // Adjust base address with the virtual address of the PT_LOAD segment
665       // corresponding to offset 0
666       if (ph.p_type == PT_LOAD && ph.p_offset == 0) {
667         base -= ph.p_vaddr;
668       }
669       if (ph.p_type == PT_DYNAMIC) {
670         dyn_addr = ph.p_vaddr;
671       }
672     }
673     if (!dyn_addr)
674       return false;
675 
676     ElfW(Dyn) *dynamic = reinterpret_cast<ElfW(Dyn) *>(dyn_addr + base);
677 
678     // The dynamic linker makes information available that helps gdb find all
679     // DSOs loaded into the program. If this information is indeed available,
680     // dump it to a MD_LINUX_DSO_DEBUG stream.
681     struct r_debug* r_debug = NULL;
682     uint32_t dynamic_length = 0;
683 
684     for (int i = 0; ; ++i) {
685       ElfW(Dyn) dyn;
686       dynamic_length += sizeof(dyn);
687       if (!dumper_->CopyFromProcess(&dyn, GetCrashThread(), dynamic + i,
688                                     sizeof(dyn))) {
689         return false;
690       }
691 
692 #ifdef __mips__
693       if (dyn.d_tag == DT_MIPS_RLD_MAP) {
694         r_debug = reinterpret_cast<struct r_debug*>(dyn.d_un.d_ptr);
695         continue;
696       }
697 #else
698       if (dyn.d_tag == DT_DEBUG) {
699         r_debug = reinterpret_cast<struct r_debug*>(dyn.d_un.d_ptr);
700         continue;
701       }
702 #endif
703       else if (dyn.d_tag == DT_NULL) {
704         break;
705       }
706     }
707 
708     // The "r_map" field of that r_debug struct contains a linked list of all
709     // loaded DSOs.
710     // Our list of DSOs potentially is different from the ones in the crashing
711     // process. So, we have to be careful to never dereference pointers
712     // directly. Instead, we use CopyFromProcess() everywhere.
713     // See <link.h> for a more detailed discussion of the how the dynamic
714     // loader communicates with debuggers.
715 
716     // Count the number of loaded DSOs
717     int dso_count = 0;
718     struct r_debug debug_entry;
719     if (!dumper_->CopyFromProcess(&debug_entry, GetCrashThread(), r_debug,
720                                   sizeof(debug_entry))) {
721       return false;
722     }
723     for (struct link_map* ptr = debug_entry.r_map; ptr; ) {
724       struct link_map map;
725       if (!dumper_->CopyFromProcess(&map, GetCrashThread(), ptr, sizeof(map)))
726         return false;
727 
728       ptr = map.l_next;
729       dso_count++;
730     }
731 
732     MDRVA linkmap_rva = minidump_writer_.kInvalidMDRVA;
733     if (dso_count > 0) {
734       // If we have at least one DSO, create an array of MDRawLinkMap
735       // entries in the minidump file.
736       TypedMDRVA<MDRawLinkMap> linkmap(&minidump_writer_);
737       if (!linkmap.AllocateArray(dso_count))
738         return false;
739       linkmap_rva = linkmap.location().rva;
740       int idx = 0;
741 
742       // Iterate over DSOs and write their information to mini dump
743       for (struct link_map* ptr = debug_entry.r_map; ptr; ) {
744         struct link_map map;
745         if (!dumper_->CopyFromProcess(&map, GetCrashThread(), ptr, sizeof(map)))
746           return  false;
747 
748         ptr = map.l_next;
749         char filename[257] = { 0 };
750         if (map.l_name) {
751           dumper_->CopyFromProcess(filename, GetCrashThread(), map.l_name,
752                                    sizeof(filename) - 1);
753         }
754         MDLocationDescriptor location;
755         if (!minidump_writer_.WriteString(filename, 0, &location))
756           return false;
757         MDRawLinkMap entry;
758         entry.name = location.rva;
759         entry.addr = map.l_addr;
760         entry.ld = reinterpret_cast<uintptr_t>(map.l_ld);
761         linkmap.CopyIndex(idx++, &entry);
762       }
763     }
764 
765     // Write MD_LINUX_DSO_DEBUG record
766     TypedMDRVA<MDRawDebug> debug(&minidump_writer_);
767     if (!debug.AllocateObjectAndArray(1, dynamic_length))
768       return false;
769     my_memset(debug.get(), 0, sizeof(MDRawDebug));
770     dirent->stream_type = MD_LINUX_DSO_DEBUG;
771     dirent->location = debug.location();
772 
773     debug.get()->version = debug_entry.r_version;
774     debug.get()->map = linkmap_rva;
775     debug.get()->dso_count = dso_count;
776     debug.get()->brk = debug_entry.r_brk;
777     debug.get()->ldbase = debug_entry.r_ldbase;
778     debug.get()->dynamic = reinterpret_cast<uintptr_t>(dynamic);
779 
780     wasteful_vector<char> dso_debug_data(dumper_->allocator(), dynamic_length);
781     // The passed-in size to the constructor (above) is only a hint.
782     // Must call .resize() to do actual initialization of the elements.
783     dso_debug_data.resize(dynamic_length);
784     dumper_->CopyFromProcess(&dso_debug_data[0], GetCrashThread(), dynamic,
785                              dynamic_length);
786     debug.CopyIndexAfterObject(0, &dso_debug_data[0], dynamic_length);
787 
788     return true;
789   }
790 
set_minidump_size_limit(off_t limit)791   void set_minidump_size_limit(off_t limit) { minidump_size_limit_ = limit; }
792 
793  private:
Alloc(unsigned bytes)794   void* Alloc(unsigned bytes) {
795     return dumper_->allocator()->Alloc(bytes);
796   }
797 
GetCrashThread() const798   pid_t GetCrashThread() const {
799     return dumper_->crash_thread();
800   }
801 
NullifyDirectoryEntry(MDRawDirectory * dirent)802   void NullifyDirectoryEntry(MDRawDirectory* dirent) {
803     dirent->stream_type = 0;
804     dirent->location.data_size = 0;
805     dirent->location.rva = 0;
806   }
807 
808 #if defined(__i386__) || defined(__x86_64__) || defined(__mips__)
WriteCPUInformation(MDRawSystemInfo * sys_info)809   bool WriteCPUInformation(MDRawSystemInfo* sys_info) {
810     char vendor_id[sizeof(sys_info->cpu.x86_cpu_info.vendor_id) + 1] = {0};
811     static const char vendor_id_name[] = "vendor_id";
812 
813     struct CpuInfoEntry {
814       const char* info_name;
815       int value;
816       bool found;
817     } cpu_info_table[] = {
818       { "processor", -1, false },
819 #if defined(__i386__) || defined(__x86_64__)
820       { "model", 0, false },
821       { "stepping",  0, false },
822       { "cpu family", 0, false },
823 #endif
824     };
825 
826     // processor_architecture should always be set, do this first
827     sys_info->processor_architecture =
828 #if defined(__mips__)
829         MD_CPU_ARCHITECTURE_MIPS;
830 #elif defined(__i386__)
831         MD_CPU_ARCHITECTURE_X86;
832 #else
833         MD_CPU_ARCHITECTURE_AMD64;
834 #endif
835 
836     const int fd = sys_open("/proc/cpuinfo", O_RDONLY, 0);
837     if (fd < 0)
838       return false;
839 
840     {
841       PageAllocator allocator;
842       ProcCpuInfoReader* const reader = new(allocator) ProcCpuInfoReader(fd);
843       const char* field;
844       while (reader->GetNextField(&field)) {
845         for (size_t i = 0;
846              i < sizeof(cpu_info_table) / sizeof(cpu_info_table[0]);
847              i++) {
848           CpuInfoEntry* entry = &cpu_info_table[i];
849           if (i > 0 && entry->found) {
850             // except for the 'processor' field, ignore repeated values.
851             continue;
852           }
853           if (!my_strcmp(field, entry->info_name)) {
854             size_t value_len;
855             const char* value = reader->GetValueAndLen(&value_len);
856             if (value_len == 0)
857               continue;
858 
859             uintptr_t val;
860             if (my_read_decimal_ptr(&val, value) == value)
861               continue;
862 
863             entry->value = static_cast<int>(val);
864             entry->found = true;
865           }
866         }
867 
868         // special case for vendor_id
869         if (!my_strcmp(field, vendor_id_name)) {
870           size_t value_len;
871           const char* value = reader->GetValueAndLen(&value_len);
872           if (value_len > 0)
873             my_strlcpy(vendor_id, value, sizeof(vendor_id));
874         }
875       }
876       sys_close(fd);
877     }
878 
879     // make sure we got everything we wanted
880     for (size_t i = 0;
881          i < sizeof(cpu_info_table) / sizeof(cpu_info_table[0]);
882          i++) {
883       if (!cpu_info_table[i].found) {
884         return false;
885       }
886     }
887     // cpu_info_table[0] holds the last cpu id listed in /proc/cpuinfo,
888     // assuming this is the highest id, change it to the number of CPUs
889     // by adding one.
890     cpu_info_table[0].value++;
891 
892     sys_info->number_of_processors = cpu_info_table[0].value;
893 #if defined(__i386__) || defined(__x86_64__)
894     sys_info->processor_level      = cpu_info_table[3].value;
895     sys_info->processor_revision   = cpu_info_table[1].value << 8 |
896                                      cpu_info_table[2].value;
897 #endif
898 
899     if (vendor_id[0] != '\0') {
900       my_memcpy(sys_info->cpu.x86_cpu_info.vendor_id, vendor_id,
901                 sizeof(sys_info->cpu.x86_cpu_info.vendor_id));
902     }
903     return true;
904   }
905 #elif defined(__arm__) || defined(__aarch64__)
WriteCPUInformation(MDRawSystemInfo * sys_info)906   bool WriteCPUInformation(MDRawSystemInfo* sys_info) {
907     // The CPUID value is broken up in several entries in /proc/cpuinfo.
908     // This table is used to rebuild it from the entries.
909     const struct CpuIdEntry {
910       const char* field;
911       char        format;
912       char        bit_lshift;
913       char        bit_length;
914     } cpu_id_entries[] = {
915       { "CPU implementer", 'x', 24, 8 },
916       { "CPU variant", 'x', 20, 4 },
917       { "CPU part", 'x', 4, 12 },
918       { "CPU revision", 'd', 0, 4 },
919     };
920 
921     // The ELF hwcaps are listed in the "Features" entry as textual tags.
922     // This table is used to rebuild them.
923     const struct CpuFeaturesEntry {
924       const char* tag;
925       uint32_t hwcaps;
926     } cpu_features_entries[] = {
927 #if defined(__arm__)
928       { "swp",  MD_CPU_ARM_ELF_HWCAP_SWP },
929       { "half", MD_CPU_ARM_ELF_HWCAP_HALF },
930       { "thumb", MD_CPU_ARM_ELF_HWCAP_THUMB },
931       { "26bit", MD_CPU_ARM_ELF_HWCAP_26BIT },
932       { "fastmult", MD_CPU_ARM_ELF_HWCAP_FAST_MULT },
933       { "fpa", MD_CPU_ARM_ELF_HWCAP_FPA },
934       { "vfp", MD_CPU_ARM_ELF_HWCAP_VFP },
935       { "edsp", MD_CPU_ARM_ELF_HWCAP_EDSP },
936       { "java", MD_CPU_ARM_ELF_HWCAP_JAVA },
937       { "iwmmxt", MD_CPU_ARM_ELF_HWCAP_IWMMXT },
938       { "crunch", MD_CPU_ARM_ELF_HWCAP_CRUNCH },
939       { "thumbee", MD_CPU_ARM_ELF_HWCAP_THUMBEE },
940       { "neon", MD_CPU_ARM_ELF_HWCAP_NEON },
941       { "vfpv3", MD_CPU_ARM_ELF_HWCAP_VFPv3 },
942       { "vfpv3d16", MD_CPU_ARM_ELF_HWCAP_VFPv3D16 },
943       { "tls", MD_CPU_ARM_ELF_HWCAP_TLS },
944       { "vfpv4", MD_CPU_ARM_ELF_HWCAP_VFPv4 },
945       { "idiva", MD_CPU_ARM_ELF_HWCAP_IDIVA },
946       { "idivt", MD_CPU_ARM_ELF_HWCAP_IDIVT },
947       { "idiv", MD_CPU_ARM_ELF_HWCAP_IDIVA | MD_CPU_ARM_ELF_HWCAP_IDIVT },
948 #elif defined(__aarch64__)
949       // No hwcaps on aarch64.
950 #endif
951     };
952 
953     // processor_architecture should always be set, do this first
954     sys_info->processor_architecture =
955 #if defined(__aarch64__)
956         MD_CPU_ARCHITECTURE_ARM64;
957 #else
958         MD_CPU_ARCHITECTURE_ARM;
959 #endif
960 
961     // /proc/cpuinfo is not readable under various sandboxed environments
962     // (e.g. Android services with the android:isolatedProcess attribute)
963     // prepare for this by setting default values now, which will be
964     // returned when this happens.
965     //
966     // Note: Bogus values are used to distinguish between failures (to
967     //       read /sys and /proc files) and really badly configured kernels.
968     sys_info->number_of_processors = 0;
969     sys_info->processor_level = 1U;  // There is no ARMv1
970     sys_info->processor_revision = 42;
971     sys_info->cpu.arm_cpu_info.cpuid = 0;
972     sys_info->cpu.arm_cpu_info.elf_hwcaps = 0;
973 
974     // Counting the number of CPUs involves parsing two sysfs files,
975     // because the content of /proc/cpuinfo will only mirror the number
976     // of 'online' cores, and thus will vary with time.
977     // See http://www.kernel.org/doc/Documentation/cputopology.txt
978     {
979       CpuSet cpus_present;
980       CpuSet cpus_possible;
981 
982       int fd = sys_open("/sys/devices/system/cpu/present", O_RDONLY, 0);
983       if (fd >= 0) {
984         cpus_present.ParseSysFile(fd);
985         sys_close(fd);
986 
987         fd = sys_open("/sys/devices/system/cpu/possible", O_RDONLY, 0);
988         if (fd >= 0) {
989           cpus_possible.ParseSysFile(fd);
990           sys_close(fd);
991 
992           cpus_present.IntersectWith(cpus_possible);
993           int cpu_count = cpus_present.GetCount();
994           if (cpu_count > 255)
995             cpu_count = 255;
996           sys_info->number_of_processors = static_cast<uint8_t>(cpu_count);
997         }
998       }
999     }
1000 
1001     // Parse /proc/cpuinfo to reconstruct the CPUID value, as well
1002     // as the ELF hwcaps field. For the latter, it would be easier to
1003     // read /proc/self/auxv but unfortunately, this file is not always
1004     // readable from regular Android applications on later versions
1005     // (>= 4.1) of the Android platform.
1006     const int fd = sys_open("/proc/cpuinfo", O_RDONLY, 0);
1007     if (fd < 0) {
1008       // Do not return false here to allow the minidump generation
1009       // to happen properly.
1010       return true;
1011     }
1012 
1013     {
1014       PageAllocator allocator;
1015       ProcCpuInfoReader* const reader =
1016           new(allocator) ProcCpuInfoReader(fd);
1017       const char* field;
1018       while (reader->GetNextField(&field)) {
1019         for (size_t i = 0;
1020              i < sizeof(cpu_id_entries)/sizeof(cpu_id_entries[0]);
1021              ++i) {
1022           const CpuIdEntry* entry = &cpu_id_entries[i];
1023           if (my_strcmp(entry->field, field) != 0)
1024             continue;
1025           uintptr_t result = 0;
1026           const char* value = reader->GetValue();
1027           const char* p = value;
1028           if (value[0] == '0' && value[1] == 'x') {
1029             p = my_read_hex_ptr(&result, value+2);
1030           } else if (entry->format == 'x') {
1031             p = my_read_hex_ptr(&result, value);
1032           } else {
1033             p = my_read_decimal_ptr(&result, value);
1034           }
1035           if (p == value)
1036             continue;
1037 
1038           result &= (1U << entry->bit_length)-1;
1039           result <<= entry->bit_lshift;
1040           sys_info->cpu.arm_cpu_info.cpuid |=
1041               static_cast<uint32_t>(result);
1042         }
1043 #if defined(__arm__)
1044         // Get the architecture version from the "Processor" field.
1045         // Note that it is also available in the "CPU architecture" field,
1046         // however, some existing kernels are misconfigured and will report
1047         // invalid values here (e.g. 6, while the CPU is ARMv7-A based).
1048         // The "Processor" field doesn't have this issue.
1049         if (!my_strcmp(field, "Processor")) {
1050           size_t value_len;
1051           const char* value = reader->GetValueAndLen(&value_len);
1052           // Expected format: <text> (v<level><endian>)
1053           // Where <text> is some text like "ARMv7 Processor rev 2"
1054           // and <level> is a decimal corresponding to the ARM
1055           // architecture number. <endian> is either 'l' or 'b'
1056           // and corresponds to the endianess, it is ignored here.
1057           while (value_len > 0 && my_isspace(value[value_len-1]))
1058             value_len--;
1059 
1060           size_t nn = value_len;
1061           while (nn > 0 && value[nn-1] != '(')
1062             nn--;
1063           if (nn > 0 && value[nn] == 'v') {
1064             uintptr_t arch_level = 5;
1065             my_read_decimal_ptr(&arch_level, value + nn + 1);
1066             sys_info->processor_level = static_cast<uint16_t>(arch_level);
1067           }
1068         }
1069 #elif defined(__aarch64__)
1070         // The aarch64 architecture does not provide the architecture level
1071         // in the Processor field, so we instead check the "CPU architecture"
1072         // field.
1073         if (!my_strcmp(field, "CPU architecture")) {
1074           uintptr_t arch_level = 0;
1075           const char* value = reader->GetValue();
1076           const char* p = value;
1077           p = my_read_decimal_ptr(&arch_level, value);
1078           if (p == value)
1079             continue;
1080           sys_info->processor_level = static_cast<uint16_t>(arch_level);
1081         }
1082 #endif
1083         // Rebuild the ELF hwcaps from the 'Features' field.
1084         if (!my_strcmp(field, "Features")) {
1085           size_t value_len;
1086           const char* value = reader->GetValueAndLen(&value_len);
1087 
1088           // Parse each space-separated tag.
1089           while (value_len > 0) {
1090             const char* tag = value;
1091             size_t tag_len = value_len;
1092             const char* p = my_strchr(tag, ' ');
1093             if (p != NULL) {
1094               tag_len = static_cast<size_t>(p - tag);
1095               value += tag_len + 1;
1096               value_len -= tag_len + 1;
1097             } else {
1098               tag_len = strlen(tag);
1099               value_len = 0;
1100             }
1101             for (size_t i = 0;
1102                 i < sizeof(cpu_features_entries)/
1103                     sizeof(cpu_features_entries[0]);
1104                 ++i) {
1105               const CpuFeaturesEntry* entry = &cpu_features_entries[i];
1106               if (tag_len == strlen(entry->tag) &&
1107                   !memcmp(tag, entry->tag, tag_len)) {
1108                 sys_info->cpu.arm_cpu_info.elf_hwcaps |= entry->hwcaps;
1109                 break;
1110               }
1111             }
1112           }
1113         }
1114       }
1115       sys_close(fd);
1116     }
1117 
1118     return true;
1119   }
1120 #else
1121 #  error "Unsupported CPU"
1122 #endif
1123 
WriteFile(MDLocationDescriptor * result,const char * filename)1124   bool WriteFile(MDLocationDescriptor* result, const char* filename) {
1125     const int fd = sys_open(filename, O_RDONLY, 0);
1126     if (fd < 0)
1127       return false;
1128 
1129     // We can't stat the files because several of the files that we want to
1130     // read are kernel seqfiles, which always have a length of zero. So we have
1131     // to read as much as we can into a buffer.
1132     static const unsigned kBufSize = 1024 - 2*sizeof(void*);
1133     struct Buffers {
1134       Buffers* next;
1135       size_t len;
1136       uint8_t data[kBufSize];
1137     } *buffers = reinterpret_cast<Buffers*>(Alloc(sizeof(Buffers)));
1138     buffers->next = NULL;
1139     buffers->len = 0;
1140 
1141     size_t total = 0;
1142     for (Buffers* bufptr = buffers;;) {
1143       ssize_t r;
1144       do {
1145         r = sys_read(fd, &bufptr->data[bufptr->len], kBufSize - bufptr->len);
1146       } while (r == -1 && errno == EINTR);
1147 
1148       if (r < 1)
1149         break;
1150 
1151       total += r;
1152       bufptr->len += r;
1153       if (bufptr->len == kBufSize) {
1154         bufptr->next = reinterpret_cast<Buffers*>(Alloc(sizeof(Buffers)));
1155         bufptr = bufptr->next;
1156         bufptr->next = NULL;
1157         bufptr->len = 0;
1158       }
1159     }
1160     sys_close(fd);
1161 
1162     if (!total)
1163       return false;
1164 
1165     UntypedMDRVA memory(&minidump_writer_);
1166     if (!memory.Allocate(total))
1167       return false;
1168     for (MDRVA pos = memory.position(); buffers; buffers = buffers->next) {
1169       // Check for special case of a zero-length buffer.  This should only
1170       // occur if a file's size happens to be a multiple of the buffer's
1171       // size, in which case the final sys_read() will have resulted in
1172       // zero bytes being read after the final buffer was just allocated.
1173       if (buffers->len == 0) {
1174         // This can only occur with final buffer.
1175         assert(buffers->next == NULL);
1176         continue;
1177       }
1178       memory.Copy(pos, &buffers->data, buffers->len);
1179       pos += buffers->len;
1180     }
1181     *result = memory.location();
1182     return true;
1183   }
1184 
WriteOSInformation(MDRawSystemInfo * sys_info)1185   bool WriteOSInformation(MDRawSystemInfo* sys_info) {
1186 #if defined(__ANDROID__)
1187     sys_info->platform_id = MD_OS_ANDROID;
1188 #else
1189     sys_info->platform_id = MD_OS_LINUX;
1190 #endif
1191 
1192     struct utsname uts;
1193     if (uname(&uts))
1194       return false;
1195 
1196     static const size_t buf_len = 512;
1197     char buf[buf_len] = {0};
1198     size_t space_left = buf_len - 1;
1199     const char* info_table[] = {
1200       uts.sysname,
1201       uts.release,
1202       uts.version,
1203       uts.machine,
1204       NULL
1205     };
1206     bool first_item = true;
1207     for (const char** cur_info = info_table; *cur_info; cur_info++) {
1208       static const char separator[] = " ";
1209       size_t separator_len = sizeof(separator) - 1;
1210       size_t info_len = my_strlen(*cur_info);
1211       if (info_len == 0)
1212         continue;
1213 
1214       if (space_left < info_len + (first_item ? 0 : separator_len))
1215         break;
1216 
1217       if (!first_item) {
1218         my_strlcat(buf, separator, sizeof(buf));
1219         space_left -= separator_len;
1220       }
1221 
1222       first_item = false;
1223       my_strlcat(buf, *cur_info, sizeof(buf));
1224       space_left -= info_len;
1225     }
1226 
1227     MDLocationDescriptor location;
1228     if (!minidump_writer_.WriteString(buf, 0, &location))
1229       return false;
1230     sys_info->csd_version_rva = location.rva;
1231 
1232     return true;
1233   }
1234 
WriteProcFile(MDLocationDescriptor * result,pid_t pid,const char * filename)1235   bool WriteProcFile(MDLocationDescriptor* result, pid_t pid,
1236                      const char* filename) {
1237     char buf[NAME_MAX];
1238     if (!dumper_->BuildProcPath(buf, pid, filename))
1239       return false;
1240     return WriteFile(result, buf);
1241   }
1242 
1243   // Only one of the 2 member variables below should be set to a valid value.
1244   const int fd_;  // File descriptor where the minidum should be written.
1245   const char* path_;  // Path to the file where the minidum should be written.
1246 
1247   const struct ucontext* const ucontext_;  // also from the signal handler
1248 #if !defined(__ARM_EABI__) && !defined(__mips__)
1249   const google_breakpad::fpstate_t* const float_state_;  // ditto
1250 #endif
1251   LinuxDumper* dumper_;
1252   MinidumpFileWriter minidump_writer_;
1253   off_t minidump_size_limit_;
1254   MDLocationDescriptor crashing_thread_context_;
1255   // Blocks of memory written to the dump. These are all currently
1256   // written while writing the thread list stream, but saved here
1257   // so a memory list stream can be written afterwards.
1258   wasteful_vector<MDMemoryDescriptor> memory_blocks_;
1259   // Additional information about some mappings provided by the caller.
1260   const MappingList& mapping_list_;
1261   // Additional memory regions to be included in the dump,
1262   // provided by the caller.
1263   const AppMemoryList& app_memory_list_;
1264 };
1265 
1266 
WriteMinidumpImpl(const char * minidump_path,int minidump_fd,off_t minidump_size_limit,pid_t crashing_process,const void * blob,size_t blob_size,const MappingList & mappings,const AppMemoryList & appmem)1267 bool WriteMinidumpImpl(const char* minidump_path,
1268                        int minidump_fd,
1269                        off_t minidump_size_limit,
1270                        pid_t crashing_process,
1271                        const void* blob, size_t blob_size,
1272                        const MappingList& mappings,
1273                        const AppMemoryList& appmem) {
1274   LinuxPtraceDumper dumper(crashing_process);
1275   const ExceptionHandler::CrashContext* context = NULL;
1276   if (blob) {
1277     if (blob_size != sizeof(ExceptionHandler::CrashContext))
1278       return false;
1279     context = reinterpret_cast<const ExceptionHandler::CrashContext*>(blob);
1280     dumper.set_crash_address(
1281         reinterpret_cast<uintptr_t>(context->siginfo.si_addr));
1282     dumper.set_crash_signal(context->siginfo.si_signo);
1283     dumper.set_crash_thread(context->tid);
1284   }
1285   MinidumpWriter writer(minidump_path, minidump_fd, context, mappings,
1286                         appmem, &dumper);
1287   // Set desired limit for file size of minidump (-1 means no limit).
1288   writer.set_minidump_size_limit(minidump_size_limit);
1289   if (!writer.Init())
1290     return false;
1291   return writer.Dump();
1292 }
1293 
1294 }  // namespace
1295 
1296 namespace google_breakpad {
1297 
WriteMinidump(const char * minidump_path,pid_t crashing_process,const void * blob,size_t blob_size)1298 bool WriteMinidump(const char* minidump_path, pid_t crashing_process,
1299                    const void* blob, size_t blob_size) {
1300   return WriteMinidumpImpl(minidump_path, -1, -1,
1301                            crashing_process, blob, blob_size,
1302                            MappingList(), AppMemoryList());
1303 }
1304 
WriteMinidump(int minidump_fd,pid_t crashing_process,const void * blob,size_t blob_size)1305 bool WriteMinidump(int minidump_fd, pid_t crashing_process,
1306                    const void* blob, size_t blob_size) {
1307   return WriteMinidumpImpl(NULL, minidump_fd, -1,
1308                            crashing_process, blob, blob_size,
1309                            MappingList(), AppMemoryList());
1310 }
1311 
WriteMinidump(const char * minidump_path,pid_t process,pid_t process_blamed_thread)1312 bool WriteMinidump(const char* minidump_path, pid_t process,
1313                    pid_t process_blamed_thread) {
1314   LinuxPtraceDumper dumper(process);
1315   // MinidumpWriter will set crash address
1316   dumper.set_crash_signal(MD_EXCEPTION_CODE_LIN_DUMP_REQUESTED);
1317   dumper.set_crash_thread(process_blamed_thread);
1318   MinidumpWriter writer(minidump_path, -1, NULL, MappingList(),
1319                         AppMemoryList(), &dumper);
1320   if (!writer.Init())
1321     return false;
1322   return writer.Dump();
1323 }
1324 
WriteMinidump(const char * minidump_path,pid_t crashing_process,const void * blob,size_t blob_size,const MappingList & mappings,const AppMemoryList & appmem)1325 bool WriteMinidump(const char* minidump_path, pid_t crashing_process,
1326                    const void* blob, size_t blob_size,
1327                    const MappingList& mappings,
1328                    const AppMemoryList& appmem) {
1329   return WriteMinidumpImpl(minidump_path, -1, -1, crashing_process,
1330                            blob, blob_size,
1331                            mappings, appmem);
1332 }
1333 
WriteMinidump(int minidump_fd,pid_t crashing_process,const void * blob,size_t blob_size,const MappingList & mappings,const AppMemoryList & appmem)1334 bool WriteMinidump(int minidump_fd, pid_t crashing_process,
1335                    const void* blob, size_t blob_size,
1336                    const MappingList& mappings,
1337                    const AppMemoryList& appmem) {
1338   return WriteMinidumpImpl(NULL, minidump_fd, -1, crashing_process,
1339                            blob, blob_size,
1340                            mappings, appmem);
1341 }
1342 
WriteMinidump(const char * minidump_path,off_t minidump_size_limit,pid_t crashing_process,const void * blob,size_t blob_size,const MappingList & mappings,const AppMemoryList & appmem)1343 bool WriteMinidump(const char* minidump_path, off_t minidump_size_limit,
1344                    pid_t crashing_process,
1345                    const void* blob, size_t blob_size,
1346                    const MappingList& mappings,
1347                    const AppMemoryList& appmem) {
1348   return WriteMinidumpImpl(minidump_path, -1, minidump_size_limit,
1349                            crashing_process, blob, blob_size,
1350                            mappings, appmem);
1351 }
1352 
WriteMinidump(int minidump_fd,off_t minidump_size_limit,pid_t crashing_process,const void * blob,size_t blob_size,const MappingList & mappings,const AppMemoryList & appmem)1353 bool WriteMinidump(int minidump_fd, off_t minidump_size_limit,
1354                    pid_t crashing_process,
1355                    const void* blob, size_t blob_size,
1356                    const MappingList& mappings,
1357                    const AppMemoryList& appmem) {
1358   return WriteMinidumpImpl(NULL, minidump_fd, minidump_size_limit,
1359                            crashing_process, blob, blob_size,
1360                            mappings, appmem);
1361 }
1362 
WriteMinidump(const char * filename,const MappingList & mappings,const AppMemoryList & appmem,LinuxDumper * dumper)1363 bool WriteMinidump(const char* filename,
1364                    const MappingList& mappings,
1365                    const AppMemoryList& appmem,
1366                    LinuxDumper* dumper) {
1367   MinidumpWriter writer(filename, -1, NULL, mappings, appmem, dumper);
1368   if (!writer.Init())
1369     return false;
1370   return writer.Dump();
1371 }
1372 
1373 }  // namespace google_breakpad
1374