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1 // Copyright (c) 2009, 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 // Converts a minidump file to a core file which gdb can read.
31 // Large parts lifted from the userspace core dumper:
32 //   http://code.google.com/p/google-coredumper/
33 //
34 // Usage: minidump-2-core [-v] 1234.dmp > core
35 
36 #include <elf.h>
37 #include <errno.h>
38 #include <inttypes.h>
39 #include <link.h>
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <sys/user.h>
44 #include <unistd.h>
45 
46 #include <map>
47 #include <string>
48 #include <vector>
49 
50 #include "common/linux/memory_mapped_file.h"
51 #include "common/minidump_type_helper.h"
52 #include "common/scoped_ptr.h"
53 #include "google_breakpad/common/minidump_format.h"
54 #include "third_party/lss/linux_syscall_support.h"
55 #include "tools/linux/md2core/minidump_memory_range.h"
56 
57 #if __WORDSIZE == 64
58   #define ELF_CLASS ELFCLASS64
59 #else
60   #define ELF_CLASS ELFCLASS32
61 #endif
62 #define Ehdr   ElfW(Ehdr)
63 #define Phdr   ElfW(Phdr)
64 #define Shdr   ElfW(Shdr)
65 #define Nhdr   ElfW(Nhdr)
66 #define auxv_t ElfW(auxv_t)
67 
68 
69 #if defined(__x86_64__)
70   #define ELF_ARCH  EM_X86_64
71 #elif defined(__i386__)
72   #define ELF_ARCH  EM_386
73 #elif defined(__arm__)
74   #define ELF_ARCH  EM_ARM
75 #elif defined(__mips__)
76   #define ELF_ARCH  EM_MIPS
77 #endif
78 
79 #if defined(__arm__)
80 // GLibc/ARM and Android/ARM both use 'user_regs' for the structure type
81 // containing core registers, while they use 'user_regs_struct' on other
82 // architectures. This file-local typedef simplifies the source code.
83 typedef user_regs user_regs_struct;
84 #endif
85 
86 using google_breakpad::MDTypeHelper;
87 using google_breakpad::MemoryMappedFile;
88 using google_breakpad::MinidumpMemoryRange;
89 
90 typedef MDTypeHelper<sizeof(ElfW(Addr))>::MDRawDebug MDRawDebug;
91 typedef MDTypeHelper<sizeof(ElfW(Addr))>::MDRawLinkMap MDRawLinkMap;
92 
93 static const MDRVA kInvalidMDRVA = static_cast<MDRVA>(-1);
94 static bool verbose;
95 static std::string g_custom_so_basedir;
96 
usage(const char * argv0)97 static int usage(const char* argv0) {
98   fprintf(stderr, "Usage: %s [-v] <minidump file>\n", argv0);
99   return 1;
100 }
101 
102 // Write all of the given buffer, handling short writes and EINTR. Return true
103 // iff successful.
104 static bool
writea(int fd,const void * idata,size_t length)105 writea(int fd, const void* idata, size_t length) {
106   const uint8_t* data = (const uint8_t*) idata;
107 
108   size_t done = 0;
109   while (done < length) {
110     ssize_t r;
111     do {
112       r = write(fd, data + done, length - done);
113     } while (r == -1 && errno == EINTR);
114 
115     if (r < 1)
116       return false;
117     done += r;
118   }
119 
120   return true;
121 }
122 
123 /* Dynamically determines the byte sex of the system. Returns non-zero
124  * for big-endian machines.
125  */
sex()126 static inline int sex() {
127   int probe = 1;
128   return !*(char *)&probe;
129 }
130 
131 typedef struct elf_timeval {    /* Time value with microsecond resolution    */
132   long tv_sec;                  /* Seconds                                   */
133   long tv_usec;                 /* Microseconds                              */
134 } elf_timeval;
135 
136 typedef struct elf_siginfo {    /* Information about signal (unused)         */
137   int32_t si_signo;             /* Signal number                             */
138   int32_t si_code;              /* Extra code                                */
139   int32_t si_errno;             /* Errno                                     */
140 } elf_siginfo;
141 
142 typedef struct prstatus {       /* Information about thread; includes CPU reg*/
143   elf_siginfo    pr_info;       /* Info associated with signal               */
144   uint16_t       pr_cursig;     /* Current signal                            */
145   unsigned long  pr_sigpend;    /* Set of pending signals                    */
146   unsigned long  pr_sighold;    /* Set of held signals                       */
147   pid_t          pr_pid;        /* Process ID                                */
148   pid_t          pr_ppid;       /* Parent's process ID                       */
149   pid_t          pr_pgrp;       /* Group ID                                  */
150   pid_t          pr_sid;        /* Session ID                                */
151   elf_timeval    pr_utime;      /* User time                                 */
152   elf_timeval    pr_stime;      /* System time                               */
153   elf_timeval    pr_cutime;     /* Cumulative user time                      */
154   elf_timeval    pr_cstime;     /* Cumulative system time                    */
155   user_regs_struct pr_reg;      /* CPU registers                             */
156   uint32_t       pr_fpvalid;    /* True if math co-processor being used      */
157 } prstatus;
158 
159 typedef struct prpsinfo {       /* Information about process                 */
160   unsigned char  pr_state;      /* Numeric process state                     */
161   char           pr_sname;      /* Char for pr_state                         */
162   unsigned char  pr_zomb;       /* Zombie                                    */
163   signed char    pr_nice;       /* Nice val                                  */
164   unsigned long  pr_flag;       /* Flags                                     */
165 #if defined(__x86_64__) || defined(__mips__)
166   uint32_t       pr_uid;        /* User ID                                   */
167   uint32_t       pr_gid;        /* Group ID                                  */
168 #else
169   uint16_t       pr_uid;        /* User ID                                   */
170   uint16_t       pr_gid;        /* Group ID                                  */
171 #endif
172   pid_t          pr_pid;        /* Process ID                                */
173   pid_t          pr_ppid;       /* Parent's process ID                       */
174   pid_t          pr_pgrp;       /* Group ID                                  */
175   pid_t          pr_sid;        /* Session ID                                */
176   char           pr_fname[16];  /* Filename of executable                    */
177   char           pr_psargs[80]; /* Initial part of arg list                  */
178 } prpsinfo;
179 
180 // We parse the minidump file and keep the parsed information in this structure
181 struct CrashedProcess {
CrashedProcessCrashedProcess182   CrashedProcess()
183       : crashing_tid(-1),
184         auxv(NULL),
185         auxv_length(0) {
186     memset(&prps, 0, sizeof(prps));
187     prps.pr_sname = 'R';
188     memset(&debug, 0, sizeof(debug));
189   }
190 
191   struct Mapping {
MappingCrashedProcess::Mapping192     Mapping()
193       : permissions(0xFFFFFFFF),
194         start_address(0),
195         end_address(0),
196         offset(0) {
197     }
198 
199     uint32_t permissions;
200     uint64_t start_address, end_address, offset;
201     std::string filename;
202     std::string data;
203   };
204   std::map<uint64_t, Mapping> mappings;
205 
206   pid_t crashing_tid;
207   int fatal_signal;
208 
209   struct Thread {
210     pid_t tid;
211     user_regs_struct regs;
212 #if defined(__i386__) || defined(__x86_64__) || defined(__mips__)
213     user_fpregs_struct fpregs;
214 #endif
215 #if defined(__i386__)
216     user_fpxregs_struct fpxregs;
217 #endif
218     uintptr_t stack_addr;
219     const uint8_t* stack;
220     size_t stack_length;
221   };
222   std::vector<Thread> threads;
223 
224   const uint8_t* auxv;
225   size_t auxv_length;
226 
227   prpsinfo prps;
228 
229   std::map<uintptr_t, std::string> signatures;
230 
231   std::string dynamic_data;
232   MDRawDebug debug;
233   std::vector<MDRawLinkMap> link_map;
234 };
235 
236 #if defined(__i386__)
237 static uint32_t
U32(const uint8_t * data)238 U32(const uint8_t* data) {
239   uint32_t v;
240   memcpy(&v, data, sizeof(v));
241   return v;
242 }
243 
244 static uint16_t
U16(const uint8_t * data)245 U16(const uint8_t* data) {
246   uint16_t v;
247   memcpy(&v, data, sizeof(v));
248   return v;
249 }
250 
251 static void
ParseThreadRegisters(CrashedProcess::Thread * thread,const MinidumpMemoryRange & range)252 ParseThreadRegisters(CrashedProcess::Thread* thread,
253                      const MinidumpMemoryRange& range) {
254   const MDRawContextX86* rawregs = range.GetData<MDRawContextX86>(0);
255 
256   thread->regs.ebx = rawregs->ebx;
257   thread->regs.ecx = rawregs->ecx;
258   thread->regs.edx = rawregs->edx;
259   thread->regs.esi = rawregs->esi;
260   thread->regs.edi = rawregs->edi;
261   thread->regs.ebp = rawregs->ebp;
262   thread->regs.eax = rawregs->eax;
263   thread->regs.xds = rawregs->ds;
264   thread->regs.xes = rawregs->es;
265   thread->regs.xfs = rawregs->fs;
266   thread->regs.xgs = rawregs->gs;
267   thread->regs.orig_eax = rawregs->eax;
268   thread->regs.eip = rawregs->eip;
269   thread->regs.xcs = rawregs->cs;
270   thread->regs.eflags = rawregs->eflags;
271   thread->regs.esp = rawregs->esp;
272   thread->regs.xss = rawregs->ss;
273 
274   thread->fpregs.cwd = rawregs->float_save.control_word;
275   thread->fpregs.swd = rawregs->float_save.status_word;
276   thread->fpregs.twd = rawregs->float_save.tag_word;
277   thread->fpregs.fip = rawregs->float_save.error_offset;
278   thread->fpregs.fcs = rawregs->float_save.error_selector;
279   thread->fpregs.foo = rawregs->float_save.data_offset;
280   thread->fpregs.fos = rawregs->float_save.data_selector;
281   memcpy(thread->fpregs.st_space, rawregs->float_save.register_area,
282          10 * 8);
283 
284   thread->fpxregs.cwd = rawregs->float_save.control_word;
285   thread->fpxregs.swd = rawregs->float_save.status_word;
286   thread->fpxregs.twd = rawregs->float_save.tag_word;
287   thread->fpxregs.fop = U16(rawregs->extended_registers + 6);
288   thread->fpxregs.fip = U16(rawregs->extended_registers + 8);
289   thread->fpxregs.fcs = U16(rawregs->extended_registers + 12);
290   thread->fpxregs.foo = U16(rawregs->extended_registers + 16);
291   thread->fpxregs.fos = U16(rawregs->extended_registers + 20);
292   thread->fpxregs.mxcsr = U32(rawregs->extended_registers + 24);
293   memcpy(thread->fpxregs.st_space, rawregs->extended_registers + 32, 128);
294   memcpy(thread->fpxregs.xmm_space, rawregs->extended_registers + 160, 128);
295 }
296 #elif defined(__x86_64__)
297 static void
ParseThreadRegisters(CrashedProcess::Thread * thread,const MinidumpMemoryRange & range)298 ParseThreadRegisters(CrashedProcess::Thread* thread,
299                      const MinidumpMemoryRange& range) {
300   const MDRawContextAMD64* rawregs = range.GetData<MDRawContextAMD64>(0);
301 
302   thread->regs.r15 = rawregs->r15;
303   thread->regs.r14 = rawregs->r14;
304   thread->regs.r13 = rawregs->r13;
305   thread->regs.r12 = rawregs->r12;
306   thread->regs.rbp = rawregs->rbp;
307   thread->regs.rbx = rawregs->rbx;
308   thread->regs.r11 = rawregs->r11;
309   thread->regs.r10 = rawregs->r10;
310   thread->regs.r9 = rawregs->r9;
311   thread->regs.r8 = rawregs->r8;
312   thread->regs.rax = rawregs->rax;
313   thread->regs.rcx = rawregs->rcx;
314   thread->regs.rdx = rawregs->rdx;
315   thread->regs.rsi = rawregs->rsi;
316   thread->regs.rdi = rawregs->rdi;
317   thread->regs.orig_rax = rawregs->rax;
318   thread->regs.rip = rawregs->rip;
319   thread->regs.cs  = rawregs->cs;
320   thread->regs.eflags = rawregs->eflags;
321   thread->regs.rsp = rawregs->rsp;
322   thread->regs.ss = rawregs->ss;
323   thread->regs.fs_base = 0;
324   thread->regs.gs_base = 0;
325   thread->regs.ds = rawregs->ds;
326   thread->regs.es = rawregs->es;
327   thread->regs.fs = rawregs->fs;
328   thread->regs.gs = rawregs->gs;
329 
330   thread->fpregs.cwd = rawregs->flt_save.control_word;
331   thread->fpregs.swd = rawregs->flt_save.status_word;
332   thread->fpregs.ftw = rawregs->flt_save.tag_word;
333   thread->fpregs.fop = rawregs->flt_save.error_opcode;
334   thread->fpregs.rip = rawregs->flt_save.error_offset;
335   thread->fpregs.rdp = rawregs->flt_save.data_offset;
336   thread->fpregs.mxcsr = rawregs->flt_save.mx_csr;
337   thread->fpregs.mxcr_mask = rawregs->flt_save.mx_csr_mask;
338   memcpy(thread->fpregs.st_space, rawregs->flt_save.float_registers, 8 * 16);
339   memcpy(thread->fpregs.xmm_space, rawregs->flt_save.xmm_registers, 16 * 16);
340 }
341 #elif defined(__arm__)
342 static void
ParseThreadRegisters(CrashedProcess::Thread * thread,const MinidumpMemoryRange & range)343 ParseThreadRegisters(CrashedProcess::Thread* thread,
344                      const MinidumpMemoryRange& range) {
345   const MDRawContextARM* rawregs = range.GetData<MDRawContextARM>(0);
346 
347   thread->regs.uregs[0] = rawregs->iregs[0];
348   thread->regs.uregs[1] = rawregs->iregs[1];
349   thread->regs.uregs[2] = rawregs->iregs[2];
350   thread->regs.uregs[3] = rawregs->iregs[3];
351   thread->regs.uregs[4] = rawregs->iregs[4];
352   thread->regs.uregs[5] = rawregs->iregs[5];
353   thread->regs.uregs[6] = rawregs->iregs[6];
354   thread->regs.uregs[7] = rawregs->iregs[7];
355   thread->regs.uregs[8] = rawregs->iregs[8];
356   thread->regs.uregs[9] = rawregs->iregs[9];
357   thread->regs.uregs[10] = rawregs->iregs[10];
358   thread->regs.uregs[11] = rawregs->iregs[11];
359   thread->regs.uregs[12] = rawregs->iregs[12];
360   thread->regs.uregs[13] = rawregs->iregs[13];
361   thread->regs.uregs[14] = rawregs->iregs[14];
362   thread->regs.uregs[15] = rawregs->iregs[15];
363 
364   thread->regs.uregs[16] = rawregs->cpsr;
365   thread->regs.uregs[17] = 0;  // what is ORIG_r0 exactly?
366 }
367 #elif defined(__mips__)
368 static void
ParseThreadRegisters(CrashedProcess::Thread * thread,const MinidumpMemoryRange & range)369 ParseThreadRegisters(CrashedProcess::Thread* thread,
370                      const MinidumpMemoryRange& range) {
371   const MDRawContextMIPS* rawregs = range.GetData<MDRawContextMIPS>(0);
372 
373   for (int i = 0; i < MD_CONTEXT_MIPS_GPR_COUNT; ++i)
374     thread->regs.regs[i] = rawregs->iregs[i];
375 
376   thread->regs.lo = rawregs->mdlo;
377   thread->regs.hi = rawregs->mdhi;
378   thread->regs.epc = rawregs->epc;
379   thread->regs.badvaddr = rawregs->badvaddr;
380   thread->regs.status = rawregs->status;
381   thread->regs.cause = rawregs->cause;
382 
383   for (int i = 0; i < MD_FLOATINGSAVEAREA_MIPS_FPR_COUNT; ++i)
384     thread->fpregs.regs[i] = rawregs->float_save.regs[i];
385 
386   thread->fpregs.fpcsr = rawregs->float_save.fpcsr;
387 #if _MIPS_SIM == _ABIO32
388   thread->fpregs.fir = rawregs->float_save.fir;
389 #endif
390 }
391 #else
392 #error "This code has not been ported to your platform yet"
393 #endif
394 
395 static void
ParseThreadList(CrashedProcess * crashinfo,const MinidumpMemoryRange & range,const MinidumpMemoryRange & full_file)396 ParseThreadList(CrashedProcess* crashinfo, const MinidumpMemoryRange& range,
397                 const MinidumpMemoryRange& full_file) {
398   const uint32_t num_threads = *range.GetData<uint32_t>(0);
399   if (verbose) {
400     fprintf(stderr,
401             "MD_THREAD_LIST_STREAM:\n"
402             "Found %d threads\n"
403             "\n\n",
404             num_threads);
405   }
406   for (unsigned i = 0; i < num_threads; ++i) {
407     CrashedProcess::Thread thread;
408     memset(&thread, 0, sizeof(thread));
409     const MDRawThread* rawthread =
410         range.GetArrayElement<MDRawThread>(sizeof(uint32_t), i);
411     thread.tid = rawthread->thread_id;
412     thread.stack_addr = rawthread->stack.start_of_memory_range;
413     MinidumpMemoryRange stack_range =
414         full_file.Subrange(rawthread->stack.memory);
415     thread.stack = stack_range.data();
416     thread.stack_length = rawthread->stack.memory.data_size;
417 
418     ParseThreadRegisters(&thread,
419                          full_file.Subrange(rawthread->thread_context));
420 
421     crashinfo->threads.push_back(thread);
422   }
423 }
424 
425 static void
ParseSystemInfo(CrashedProcess * crashinfo,const MinidumpMemoryRange & range,const MinidumpMemoryRange & full_file)426 ParseSystemInfo(CrashedProcess* crashinfo, const MinidumpMemoryRange& range,
427                 const MinidumpMemoryRange& full_file) {
428   const MDRawSystemInfo* sysinfo = range.GetData<MDRawSystemInfo>(0);
429   if (!sysinfo) {
430     fprintf(stderr, "Failed to access MD_SYSTEM_INFO_STREAM\n");
431     _exit(1);
432   }
433 #if defined(__i386__)
434   if (sysinfo->processor_architecture != MD_CPU_ARCHITECTURE_X86) {
435     fprintf(stderr,
436             "This version of minidump-2-core only supports x86 (32bit)%s.\n",
437             sysinfo->processor_architecture == MD_CPU_ARCHITECTURE_AMD64 ?
438             ",\nbut the minidump file is from a 64bit machine" : "");
439     _exit(1);
440   }
441 #elif defined(__x86_64__)
442   if (sysinfo->processor_architecture != MD_CPU_ARCHITECTURE_AMD64) {
443     fprintf(stderr,
444             "This version of minidump-2-core only supports x86 (64bit)%s.\n",
445             sysinfo->processor_architecture == MD_CPU_ARCHITECTURE_X86 ?
446             ",\nbut the minidump file is from a 32bit machine" : "");
447     _exit(1);
448   }
449 #elif defined(__arm__)
450   if (sysinfo->processor_architecture != MD_CPU_ARCHITECTURE_ARM) {
451     fprintf(stderr,
452             "This version of minidump-2-core only supports ARM (32bit).\n");
453     _exit(1);
454   }
455 #elif defined(__mips__)
456   if (sysinfo->processor_architecture != MD_CPU_ARCHITECTURE_MIPS) {
457     fprintf(stderr,
458             "This version of minidump-2-core only supports mips (32bit).\n");
459     _exit(1);
460   }
461 #else
462 #error "This code has not been ported to your platform yet"
463 #endif
464   if (!strstr(full_file.GetAsciiMDString(sysinfo->csd_version_rva).c_str(),
465               "Linux") &&
466       sysinfo->platform_id != MD_OS_NACL) {
467     fprintf(stderr, "This minidump was not generated by Linux or NaCl.\n");
468     _exit(1);
469   }
470 
471   if (verbose) {
472     fprintf(stderr,
473             "MD_SYSTEM_INFO_STREAM:\n"
474             "Architecture: %s\n"
475             "Number of processors: %d\n"
476             "Processor level: %d\n"
477             "Processor model: %d\n"
478             "Processor stepping: %d\n",
479             sysinfo->processor_architecture == MD_CPU_ARCHITECTURE_X86
480             ? "i386"
481             : sysinfo->processor_architecture == MD_CPU_ARCHITECTURE_AMD64
482             ? "x86-64"
483             : sysinfo->processor_architecture == MD_CPU_ARCHITECTURE_ARM
484             ? "ARM"
485             : sysinfo->processor_architecture == MD_CPU_ARCHITECTURE_MIPS
486             ? "MIPS"
487             : "???",
488             sysinfo->number_of_processors,
489             sysinfo->processor_level,
490             sysinfo->processor_revision >> 8,
491             sysinfo->processor_revision & 0xFF);
492     if (sysinfo->processor_architecture == MD_CPU_ARCHITECTURE_X86 ||
493         sysinfo->processor_architecture == MD_CPU_ARCHITECTURE_AMD64) {
494       fputs("Vendor id: ", stderr);
495       const char *nul =
496         (const char *)memchr(sysinfo->cpu.x86_cpu_info.vendor_id, 0,
497                              sizeof(sysinfo->cpu.x86_cpu_info.vendor_id));
498       fwrite(sysinfo->cpu.x86_cpu_info.vendor_id,
499              nul ? nul - (const char *)&sysinfo->cpu.x86_cpu_info.vendor_id[0]
500              : sizeof(sysinfo->cpu.x86_cpu_info.vendor_id), 1, stderr);
501       fputs("\n", stderr);
502     }
503     fprintf(stderr, "OS: %s\n",
504             full_file.GetAsciiMDString(sysinfo->csd_version_rva).c_str());
505     fputs("\n\n", stderr);
506   }
507 }
508 
509 static void
ParseCPUInfo(CrashedProcess * crashinfo,const MinidumpMemoryRange & range)510 ParseCPUInfo(CrashedProcess* crashinfo, const MinidumpMemoryRange& range) {
511   if (verbose) {
512     fputs("MD_LINUX_CPU_INFO:\n", stderr);
513     fwrite(range.data(), range.length(), 1, stderr);
514     fputs("\n\n\n", stderr);
515   }
516 }
517 
518 static void
ParseProcessStatus(CrashedProcess * crashinfo,const MinidumpMemoryRange & range)519 ParseProcessStatus(CrashedProcess* crashinfo,
520                    const MinidumpMemoryRange& range) {
521   if (verbose) {
522     fputs("MD_LINUX_PROC_STATUS:\n", stderr);
523     fwrite(range.data(), range.length(), 1, stderr);
524     fputs("\n\n", stderr);
525   }
526 }
527 
528 static void
ParseLSBRelease(CrashedProcess * crashinfo,const MinidumpMemoryRange & range)529 ParseLSBRelease(CrashedProcess* crashinfo, const MinidumpMemoryRange& range) {
530   if (verbose) {
531     fputs("MD_LINUX_LSB_RELEASE:\n", stderr);
532     fwrite(range.data(), range.length(), 1, stderr);
533     fputs("\n\n", stderr);
534   }
535 }
536 
537 static void
ParseMaps(CrashedProcess * crashinfo,const MinidumpMemoryRange & range)538 ParseMaps(CrashedProcess* crashinfo, const MinidumpMemoryRange& range) {
539   if (verbose) {
540     fputs("MD_LINUX_MAPS:\n", stderr);
541     fwrite(range.data(), range.length(), 1, stderr);
542   }
543   for (const uint8_t* ptr = range.data();
544        ptr < range.data() + range.length();) {
545     const uint8_t* eol = (uint8_t*)memchr(ptr, '\n',
546                                        range.data() + range.length() - ptr);
547     std::string line((const char*)ptr,
548                      eol ? eol - ptr : range.data() + range.length() - ptr);
549     ptr = eol ? eol + 1 : range.data() + range.length();
550     unsigned long long start, stop, offset;
551     char* permissions = NULL;
552     char* filename = NULL;
553     sscanf(line.c_str(), "%llx-%llx %m[-rwxp] %llx %*[:0-9a-f] %*d %ms",
554            &start, &stop, &permissions, &offset, &filename);
555     if (filename && *filename == '/') {
556       CrashedProcess::Mapping mapping;
557       mapping.permissions = 0;
558       if (strchr(permissions, 'r')) {
559         mapping.permissions |= PF_R;
560       }
561       if (strchr(permissions, 'w')) {
562         mapping.permissions |= PF_W;
563       }
564       if (strchr(permissions, 'x')) {
565         mapping.permissions |= PF_X;
566       }
567       mapping.start_address = start;
568       mapping.end_address = stop;
569       mapping.offset = offset;
570       if (filename) {
571         mapping.filename = filename;
572       }
573       crashinfo->mappings[mapping.start_address] = mapping;
574     }
575     free(permissions);
576     free(filename);
577   }
578   if (verbose) {
579     fputs("\n\n\n", stderr);
580   }
581 }
582 
583 static void
ParseEnvironment(CrashedProcess * crashinfo,const MinidumpMemoryRange & range)584 ParseEnvironment(CrashedProcess* crashinfo, const MinidumpMemoryRange& range) {
585   if (verbose) {
586     fputs("MD_LINUX_ENVIRON:\n", stderr);
587     char* env = new char[range.length()];
588     memcpy(env, range.data(), range.length());
589     int nul_count = 0;
590     for (char *ptr = env;;) {
591       ptr = (char *)memchr(ptr, '\000', range.length() - (ptr - env));
592       if (!ptr) {
593         break;
594       }
595       if (ptr > env && ptr[-1] == '\n') {
596         if (++nul_count > 5) {
597           // Some versions of Chrome try to rewrite the process' command line
598           // in a way that causes the environment to be corrupted. Afterwards,
599           // part of the environment will contain the trailing bit of the
600           // command line. The rest of the environment will be filled with
601           // NUL bytes.
602           // We detect this corruption by counting the number of consecutive
603           // NUL bytes. Normally, we would not expect any consecutive NUL
604           // bytes. But we are conservative and only suppress printing of
605           // the environment if we see at least five consecutive NULs.
606           fputs("Environment has been corrupted; no data available", stderr);
607           goto env_corrupted;
608         }
609       } else {
610         nul_count = 0;
611       }
612       *ptr = '\n';
613     }
614     fwrite(env, range.length(), 1, stderr);
615   env_corrupted:
616     delete[] env;
617     fputs("\n\n\n", stderr);
618   }
619 }
620 
621 static void
ParseAuxVector(CrashedProcess * crashinfo,const MinidumpMemoryRange & range)622 ParseAuxVector(CrashedProcess* crashinfo, const MinidumpMemoryRange& range) {
623   // Some versions of Chrome erroneously used the MD_LINUX_AUXV stream value
624   // when dumping /proc/$x/maps
625   if (range.length() > 17) {
626     // The AUXV vector contains binary data, whereas the maps always begin
627     // with an 8+ digit hex address followed by a hyphen and another 8+ digit
628     // address.
629     char addresses[18];
630     memcpy(addresses, range.data(), 17);
631     addresses[17] = '\000';
632     if (strspn(addresses, "0123456789abcdef-") == 17) {
633       ParseMaps(crashinfo, range);
634       return;
635     }
636   }
637 
638   crashinfo->auxv = range.data();
639   crashinfo->auxv_length = range.length();
640 }
641 
642 static void
ParseCmdLine(CrashedProcess * crashinfo,const MinidumpMemoryRange & range)643 ParseCmdLine(CrashedProcess* crashinfo, const MinidumpMemoryRange& range) {
644   // The command line is supposed to use NUL bytes to separate arguments.
645   // As Chrome rewrites its own command line and (incorrectly) substitutes
646   // spaces, this is often not the case in our minidump files.
647   const char* cmdline = (const char*) range.data();
648   if (verbose) {
649     fputs("MD_LINUX_CMD_LINE:\n", stderr);
650     unsigned i = 0;
651     for (; i < range.length() && cmdline[i] && cmdline[i] != ' '; ++i) { }
652     fputs("argv[0] = \"", stderr);
653     fwrite(cmdline, i, 1, stderr);
654     fputs("\"\n", stderr);
655     for (unsigned j = ++i, argc = 1; j < range.length(); ++j) {
656       if (!cmdline[j] || cmdline[j] == ' ') {
657         fprintf(stderr, "argv[%d] = \"", argc++);
658         fwrite(cmdline + i, j - i, 1, stderr);
659         fputs("\"\n", stderr);
660         i = j + 1;
661       }
662     }
663     fputs("\n\n", stderr);
664   }
665 
666   const char *binary_name = cmdline;
667   for (size_t i = 0; i < range.length(); ++i) {
668     if (cmdline[i] == '/') {
669       binary_name = cmdline + i + 1;
670     } else if (cmdline[i] == 0 || cmdline[i] == ' ') {
671       static const size_t fname_len = sizeof(crashinfo->prps.pr_fname) - 1;
672       static const size_t args_len = sizeof(crashinfo->prps.pr_psargs) - 1;
673       memset(crashinfo->prps.pr_fname, 0, fname_len + 1);
674       memset(crashinfo->prps.pr_psargs, 0, args_len + 1);
675       unsigned len = cmdline + i - binary_name;
676       memcpy(crashinfo->prps.pr_fname, binary_name,
677                len > fname_len ? fname_len : len);
678 
679       len = range.length() > args_len ? args_len : range.length();
680       memcpy(crashinfo->prps.pr_psargs, cmdline, len);
681       for (unsigned j = 0; j < len; ++j) {
682         if (crashinfo->prps.pr_psargs[j] == 0)
683           crashinfo->prps.pr_psargs[j] = ' ';
684       }
685       break;
686     }
687   }
688 }
689 
690 static void
ParseDSODebugInfo(CrashedProcess * crashinfo,const MinidumpMemoryRange & range,const MinidumpMemoryRange & full_file)691 ParseDSODebugInfo(CrashedProcess* crashinfo, const MinidumpMemoryRange& range,
692                   const MinidumpMemoryRange& full_file) {
693   const MDRawDebug* debug = range.GetData<MDRawDebug>(0);
694   if (!debug) {
695     return;
696   }
697   if (verbose) {
698     fprintf(stderr,
699             "MD_LINUX_DSO_DEBUG:\n"
700             "Version: %d\n"
701             "Number of DSOs: %d\n"
702             "Brk handler: 0x%" PRIx64 "\n"
703             "Dynamic loader at: 0x%" PRIx64 "\n"
704             "_DYNAMIC: 0x%" PRIx64 "\n",
705             debug->version,
706             debug->dso_count,
707             static_cast<uint64_t>(debug->brk),
708             static_cast<uint64_t>(debug->ldbase),
709             static_cast<uint64_t>(debug->dynamic));
710   }
711   crashinfo->debug = *debug;
712   if (range.length() > sizeof(MDRawDebug)) {
713     char* dynamic_data = (char*)range.data() + sizeof(MDRawDebug);
714     crashinfo->dynamic_data.assign(dynamic_data,
715                                    range.length() - sizeof(MDRawDebug));
716   }
717   if (debug->map != kInvalidMDRVA) {
718     for (unsigned int i = 0; i < debug->dso_count; ++i) {
719       const MDRawLinkMap* link_map =
720           full_file.GetArrayElement<MDRawLinkMap>(debug->map, i);
721       if (link_map) {
722         if (verbose) {
723           fprintf(stderr,
724                   "#%03d: %" PRIx64 ", %" PRIx64 ", \"%s\"\n",
725                   i, static_cast<uint64_t>(link_map->addr),
726                   static_cast<uint64_t>(link_map->ld),
727                   full_file.GetAsciiMDString(link_map->name).c_str());
728         }
729         crashinfo->link_map.push_back(*link_map);
730       }
731     }
732   }
733   if (verbose) {
734     fputs("\n\n", stderr);
735   }
736 }
737 
738 static void
ParseExceptionStream(CrashedProcess * crashinfo,const MinidumpMemoryRange & range)739 ParseExceptionStream(CrashedProcess* crashinfo,
740                      const MinidumpMemoryRange& range) {
741   const MDRawExceptionStream* exp = range.GetData<MDRawExceptionStream>(0);
742   crashinfo->crashing_tid = exp->thread_id;
743   crashinfo->fatal_signal = (int) exp->exception_record.exception_code;
744 }
745 
746 static bool
WriteThread(const CrashedProcess::Thread & thread,int fatal_signal)747 WriteThread(const CrashedProcess::Thread& thread, int fatal_signal) {
748   struct prstatus pr;
749   memset(&pr, 0, sizeof(pr));
750 
751   pr.pr_info.si_signo = fatal_signal;
752   pr.pr_cursig = fatal_signal;
753   pr.pr_pid = thread.tid;
754   memcpy(&pr.pr_reg, &thread.regs, sizeof(user_regs_struct));
755 
756   Nhdr nhdr;
757   memset(&nhdr, 0, sizeof(nhdr));
758   nhdr.n_namesz = 5;
759   nhdr.n_descsz = sizeof(struct prstatus);
760   nhdr.n_type = NT_PRSTATUS;
761   if (!writea(1, &nhdr, sizeof(nhdr)) ||
762       !writea(1, "CORE\0\0\0\0", 8) ||
763       !writea(1, &pr, sizeof(struct prstatus))) {
764     return false;
765   }
766 
767 #if defined(__i386__) || defined(__x86_64__)
768   nhdr.n_descsz = sizeof(user_fpregs_struct);
769   nhdr.n_type = NT_FPREGSET;
770   if (!writea(1, &nhdr, sizeof(nhdr)) ||
771       !writea(1, "CORE\0\0\0\0", 8) ||
772       !writea(1, &thread.fpregs, sizeof(user_fpregs_struct))) {
773     return false;
774   }
775 #endif
776 
777 #if defined(__i386__)
778   nhdr.n_descsz = sizeof(user_fpxregs_struct);
779   nhdr.n_type = NT_PRXFPREG;
780   if (!writea(1, &nhdr, sizeof(nhdr)) ||
781       !writea(1, "LINUX\0\0\0", 8) ||
782       !writea(1, &thread.fpxregs, sizeof(user_fpxregs_struct))) {
783     return false;
784   }
785 #endif
786 
787   return true;
788 }
789 
790 static void
ParseModuleStream(CrashedProcess * crashinfo,const MinidumpMemoryRange & range,const MinidumpMemoryRange & full_file)791 ParseModuleStream(CrashedProcess* crashinfo, const MinidumpMemoryRange& range,
792                   const MinidumpMemoryRange& full_file) {
793   if (verbose) {
794     fputs("MD_MODULE_LIST_STREAM:\n", stderr);
795   }
796   const uint32_t num_mappings = *range.GetData<uint32_t>(0);
797   for (unsigned i = 0; i < num_mappings; ++i) {
798     CrashedProcess::Mapping mapping;
799     const MDRawModule* rawmodule = reinterpret_cast<const MDRawModule*>(
800         range.GetArrayElement(sizeof(uint32_t), MD_MODULE_SIZE, i));
801     mapping.start_address = rawmodule->base_of_image;
802     mapping.end_address = rawmodule->size_of_image + rawmodule->base_of_image;
803 
804     if (crashinfo->mappings.find(mapping.start_address) ==
805         crashinfo->mappings.end()) {
806       // We prefer data from MD_LINUX_MAPS over MD_MODULE_LIST_STREAM, as
807       // the former is a strict superset of the latter.
808       crashinfo->mappings[mapping.start_address] = mapping;
809     }
810 
811     const MDCVInfoPDB70* record = reinterpret_cast<const MDCVInfoPDB70*>(
812         full_file.GetData(rawmodule->cv_record.rva, MDCVInfoPDB70_minsize));
813     char guid[40];
814     sprintf(guid, "%08X-%04X-%04X-%02X%02X-%02X%02X%02X%02X%02X%02X",
815             record->signature.data1, record->signature.data2,
816             record->signature.data3,
817             record->signature.data4[0], record->signature.data4[1],
818             record->signature.data4[2], record->signature.data4[3],
819             record->signature.data4[4], record->signature.data4[5],
820             record->signature.data4[6], record->signature.data4[7]);
821     std::string filename =
822         full_file.GetAsciiMDString(rawmodule->module_name_rva);
823     size_t slash = filename.find_last_of('/');
824     std::string basename = slash == std::string::npos ?
825       filename : filename.substr(slash + 1);
826     if (strcmp(guid, "00000000-0000-0000-0000-000000000000")) {
827       std::string prefix;
828       if (!g_custom_so_basedir.empty())
829         prefix = g_custom_so_basedir;
830       else
831         prefix = std::string("/var/lib/breakpad/") + guid + "-" + basename;
832 
833       crashinfo->signatures[rawmodule->base_of_image] = prefix + basename;
834     }
835 
836     if (verbose) {
837       fprintf(stderr, "0x%08llX-0x%08llX, ChkSum: 0x%08X, GUID: %s, \"%s\"\n",
838               (unsigned long long)rawmodule->base_of_image,
839               (unsigned long long)rawmodule->base_of_image +
840               rawmodule->size_of_image,
841               rawmodule->checksum, guid, filename.c_str());
842     }
843   }
844   if (verbose) {
845     fputs("\n\n", stderr);
846   }
847 }
848 
849 static void
AddDataToMapping(CrashedProcess * crashinfo,const std::string & data,uintptr_t addr)850 AddDataToMapping(CrashedProcess* crashinfo, const std::string& data,
851                  uintptr_t addr) {
852   for (std::map<uint64_t, CrashedProcess::Mapping>::iterator
853          iter = crashinfo->mappings.begin();
854        iter != crashinfo->mappings.end();
855        ++iter) {
856     if (addr >= iter->second.start_address &&
857         addr < iter->second.end_address) {
858       CrashedProcess::Mapping mapping = iter->second;
859       if ((addr & ~4095) != iter->second.start_address) {
860         // If there are memory pages in the mapping prior to where the
861         // data starts, truncate the existing mapping so that it ends with
862         // the page immediately preceding the data region.
863         iter->second.end_address = addr & ~4095;
864         if (!mapping.filename.empty()) {
865           // "mapping" is a copy of "iter->second". We are splitting the
866           // existing mapping into two separate ones when we write the data
867           // to the core file. The first one does not have any associated
868           // data in the core file, the second one is backed by data that is
869           // included with the core file.
870           // If this mapping wasn't supposed to be anonymous, then we also
871           // have to update the file offset upon splitting the mapping.
872           mapping.offset += iter->second.end_address -
873             iter->second.start_address;
874         }
875       }
876       // Create a new mapping that contains the data contents. We often
877       // limit the amount of data that is actually written to the core
878       // file. But it is OK if the mapping itself extends past the end of
879       // the data.
880       mapping.start_address = addr & ~4095;
881       mapping.data.assign(addr & 4095, 0).append(data);
882       mapping.data.append(-mapping.data.size() & 4095, 0);
883       crashinfo->mappings[mapping.start_address] = mapping;
884       return;
885     }
886   }
887   // Didn't find a suitable existing mapping for the data. Create a new one.
888   CrashedProcess::Mapping mapping;
889   mapping.permissions = PF_R | PF_W;
890   mapping.start_address = addr & ~4095;
891   mapping.end_address =
892     (addr + data.size() + 4095) & ~4095;
893   mapping.data.assign(addr & 4095, 0).append(data);
894   mapping.data.append(-mapping.data.size() & 4095, 0);
895   crashinfo->mappings[mapping.start_address] = mapping;
896 }
897 
898 static void
AugmentMappings(CrashedProcess * crashinfo,const MinidumpMemoryRange & full_file)899 AugmentMappings(CrashedProcess* crashinfo,
900                 const MinidumpMemoryRange& full_file) {
901   // For each thread, find the memory mapping that matches the thread's stack.
902   // Then adjust the mapping to include the stack dump.
903   for (unsigned i = 0; i < crashinfo->threads.size(); ++i) {
904     const CrashedProcess::Thread& thread = crashinfo->threads[i];
905     AddDataToMapping(crashinfo,
906                      std::string((char *)thread.stack, thread.stack_length),
907                      thread.stack_addr);
908   }
909 
910   // Create a new link map with information about DSOs. We move this map to
911   // the beginning of the address space, as this area should always be
912   // available.
913   static const uintptr_t start_addr = 4096;
914   std::string data;
915   struct r_debug debug = { 0 };
916   debug.r_version = crashinfo->debug.version;
917   debug.r_brk = (ElfW(Addr))crashinfo->debug.brk;
918   debug.r_state = r_debug::RT_CONSISTENT;
919   debug.r_ldbase = (ElfW(Addr))crashinfo->debug.ldbase;
920   debug.r_map = crashinfo->debug.dso_count > 0 ?
921     (struct link_map*)(start_addr + sizeof(debug)) : 0;
922   data.append((char*)&debug, sizeof(debug));
923 
924   struct link_map* prev = 0;
925   for (std::vector<MDRawLinkMap>::iterator iter = crashinfo->link_map.begin();
926        iter != crashinfo->link_map.end();
927        ++iter) {
928     struct link_map link_map = { 0 };
929     link_map.l_addr = (ElfW(Addr))iter->addr;
930     link_map.l_name = (char*)(start_addr + data.size() + sizeof(link_map));
931     link_map.l_ld = (ElfW(Dyn)*)iter->ld;
932     link_map.l_prev = prev;
933     prev = (struct link_map*)(start_addr + data.size());
934     std::string filename = full_file.GetAsciiMDString(iter->name);
935 
936     // Look up signature for this filename. If available, change filename
937     // to point to GUID, instead.
938     std::map<uintptr_t, std::string>::const_iterator guid =
939       crashinfo->signatures.find((uintptr_t)iter->addr);
940     if (guid != crashinfo->signatures.end()) {
941       filename = guid->second;
942     }
943 
944     if (std::distance(iter, crashinfo->link_map.end()) == 1) {
945       link_map.l_next = 0;
946     } else {
947       link_map.l_next = (struct link_map*)(start_addr + data.size() +
948                                            sizeof(link_map) +
949                                            ((filename.size() + 8) & ~7));
950     }
951     data.append((char*)&link_map, sizeof(link_map));
952     data.append(filename);
953     data.append(8 - (filename.size() & 7), 0);
954   }
955   AddDataToMapping(crashinfo, data, start_addr);
956 
957   // Map the page containing the _DYNAMIC array
958   if (!crashinfo->dynamic_data.empty()) {
959     // Make _DYNAMIC DT_DEBUG entry point to our link map
960     for (int i = 0;; ++i) {
961       ElfW(Dyn) dyn;
962       if ((i+1)*sizeof(dyn) > crashinfo->dynamic_data.length()) {
963       no_dt_debug:
964         if (verbose) {
965           fprintf(stderr, "No DT_DEBUG entry found\n");
966         }
967         return;
968       }
969       memcpy(&dyn, crashinfo->dynamic_data.c_str() + i*sizeof(dyn),
970              sizeof(dyn));
971       if (dyn.d_tag == DT_DEBUG) {
972         crashinfo->dynamic_data.replace(i*sizeof(dyn) +
973                                        offsetof(ElfW(Dyn), d_un.d_ptr),
974                                        sizeof(start_addr),
975                                        (char*)&start_addr, sizeof(start_addr));
976         break;
977       } else if (dyn.d_tag == DT_NULL) {
978         goto no_dt_debug;
979       }
980     }
981     AddDataToMapping(crashinfo, crashinfo->dynamic_data,
982                      (uintptr_t)crashinfo->debug.dynamic);
983   }
984 }
985 
986 int
main(int argc,char ** argv)987 main(int argc, char** argv) {
988   int argi = 1;
989   while (argi < argc && argv[argi][0] == '-') {
990     if (!strcmp(argv[argi], "-v")) {
991       verbose = true;
992     } else if (!strcmp(argv[argi], "--sobasedir")) {
993       argi++;
994       if (argi >= argc) {
995         fprintf(stderr, "--sobasedir expects an argument.");
996         return usage(argv[0]);
997       }
998 
999       g_custom_so_basedir = argv[argi];
1000     } else {
1001       return usage(argv[0]);
1002     }
1003     argi++;
1004   }
1005 
1006   if (argc != argi + 1)
1007     return usage(argv[0]);
1008 
1009   MemoryMappedFile mapped_file(argv[argi], 0);
1010   if (!mapped_file.data()) {
1011     fprintf(stderr, "Failed to mmap dump file\n");
1012     return 1;
1013   }
1014 
1015   MinidumpMemoryRange dump(mapped_file.data(), mapped_file.size());
1016 
1017   const MDRawHeader* header = dump.GetData<MDRawHeader>(0);
1018 
1019   CrashedProcess crashinfo;
1020 
1021   // Always check the system info first, as that allows us to tell whether
1022   // this is a minidump file that is compatible with our converter.
1023   bool ok = false;
1024   for (unsigned i = 0; i < header->stream_count; ++i) {
1025     const MDRawDirectory* dirent =
1026         dump.GetArrayElement<MDRawDirectory>(header->stream_directory_rva, i);
1027     switch (dirent->stream_type) {
1028       case MD_SYSTEM_INFO_STREAM:
1029         ParseSystemInfo(&crashinfo, dump.Subrange(dirent->location), dump);
1030         ok = true;
1031         break;
1032       default:
1033         break;
1034     }
1035   }
1036   if (!ok) {
1037     fprintf(stderr, "Cannot determine input file format.\n");
1038     _exit(1);
1039   }
1040 
1041   for (unsigned i = 0; i < header->stream_count; ++i) {
1042     const MDRawDirectory* dirent =
1043         dump.GetArrayElement<MDRawDirectory>(header->stream_directory_rva, i);
1044     switch (dirent->stream_type) {
1045       case MD_THREAD_LIST_STREAM:
1046         ParseThreadList(&crashinfo, dump.Subrange(dirent->location), dump);
1047         break;
1048       case MD_LINUX_CPU_INFO:
1049         ParseCPUInfo(&crashinfo, dump.Subrange(dirent->location));
1050         break;
1051       case MD_LINUX_PROC_STATUS:
1052         ParseProcessStatus(&crashinfo, dump.Subrange(dirent->location));
1053         break;
1054       case MD_LINUX_LSB_RELEASE:
1055         ParseLSBRelease(&crashinfo, dump.Subrange(dirent->location));
1056         break;
1057       case MD_LINUX_ENVIRON:
1058         ParseEnvironment(&crashinfo, dump.Subrange(dirent->location));
1059         break;
1060       case MD_LINUX_MAPS:
1061         ParseMaps(&crashinfo, dump.Subrange(dirent->location));
1062         break;
1063       case MD_LINUX_AUXV:
1064         ParseAuxVector(&crashinfo, dump.Subrange(dirent->location));
1065         break;
1066       case MD_LINUX_CMD_LINE:
1067         ParseCmdLine(&crashinfo, dump.Subrange(dirent->location));
1068         break;
1069       case MD_LINUX_DSO_DEBUG:
1070         ParseDSODebugInfo(&crashinfo, dump.Subrange(dirent->location), dump);
1071         break;
1072       case MD_EXCEPTION_STREAM:
1073         ParseExceptionStream(&crashinfo, dump.Subrange(dirent->location));
1074         break;
1075       case MD_MODULE_LIST_STREAM:
1076         ParseModuleStream(&crashinfo, dump.Subrange(dirent->location), dump);
1077         break;
1078       default:
1079         if (verbose)
1080           fprintf(stderr, "Skipping %x\n", dirent->stream_type);
1081     }
1082   }
1083 
1084   AugmentMappings(&crashinfo, dump);
1085 
1086   // Write the ELF header. The file will look like:
1087   //   ELF header
1088   //   Phdr for the PT_NOTE
1089   //   Phdr for each of the thread stacks
1090   //   PT_NOTE
1091   //   each of the thread stacks
1092   Ehdr ehdr;
1093   memset(&ehdr, 0, sizeof(Ehdr));
1094   ehdr.e_ident[0] = ELFMAG0;
1095   ehdr.e_ident[1] = ELFMAG1;
1096   ehdr.e_ident[2] = ELFMAG2;
1097   ehdr.e_ident[3] = ELFMAG3;
1098   ehdr.e_ident[4] = ELF_CLASS;
1099   ehdr.e_ident[5] = sex() ? ELFDATA2MSB : ELFDATA2LSB;
1100   ehdr.e_ident[6] = EV_CURRENT;
1101   ehdr.e_type     = ET_CORE;
1102   ehdr.e_machine  = ELF_ARCH;
1103   ehdr.e_version  = EV_CURRENT;
1104   ehdr.e_phoff    = sizeof(Ehdr);
1105   ehdr.e_ehsize   = sizeof(Ehdr);
1106   ehdr.e_phentsize= sizeof(Phdr);
1107   ehdr.e_phnum    = 1 +                         // PT_NOTE
1108                     crashinfo.mappings.size();  // memory mappings
1109   ehdr.e_shentsize= sizeof(Shdr);
1110   if (!writea(1, &ehdr, sizeof(Ehdr)))
1111     return 1;
1112 
1113   size_t offset = sizeof(Ehdr) + ehdr.e_phnum * sizeof(Phdr);
1114   size_t filesz = sizeof(Nhdr) + 8 + sizeof(prpsinfo) +
1115                   // sizeof(Nhdr) + 8 + sizeof(user) +
1116                   sizeof(Nhdr) + 8 + crashinfo.auxv_length +
1117                   crashinfo.threads.size() * (
1118                     (sizeof(Nhdr) + 8 + sizeof(prstatus))
1119 #if defined(__i386__) || defined(__x86_64__)
1120                    + sizeof(Nhdr) + 8 + sizeof(user_fpregs_struct)
1121 #endif
1122 #if defined(__i386__)
1123                    + sizeof(Nhdr) + 8 + sizeof(user_fpxregs_struct)
1124 #endif
1125                     );
1126 
1127   Phdr phdr;
1128   memset(&phdr, 0, sizeof(Phdr));
1129   phdr.p_type = PT_NOTE;
1130   phdr.p_offset = offset;
1131   phdr.p_filesz = filesz;
1132   if (!writea(1, &phdr, sizeof(phdr)))
1133     return 1;
1134 
1135   phdr.p_type = PT_LOAD;
1136   phdr.p_align = 4096;
1137   size_t note_align = phdr.p_align - ((offset+filesz) % phdr.p_align);
1138   if (note_align == phdr.p_align)
1139     note_align = 0;
1140   offset += note_align;
1141 
1142   for (std::map<uint64_t, CrashedProcess::Mapping>::const_iterator iter =
1143          crashinfo.mappings.begin();
1144        iter != crashinfo.mappings.end(); ++iter) {
1145     const CrashedProcess::Mapping& mapping = iter->second;
1146     if (mapping.permissions == 0xFFFFFFFF) {
1147       // This is a map that we found in MD_MODULE_LIST_STREAM (as opposed to
1148       // MD_LINUX_MAPS). It lacks some of the information that we would like
1149       // to include.
1150       phdr.p_flags = PF_R;
1151     } else {
1152       phdr.p_flags = mapping.permissions;
1153     }
1154     phdr.p_vaddr = mapping.start_address;
1155     phdr.p_memsz = mapping.end_address - mapping.start_address;
1156     if (mapping.data.size()) {
1157       offset += filesz;
1158       filesz = mapping.data.size();
1159       phdr.p_filesz = mapping.data.size();
1160       phdr.p_offset = offset;
1161     } else {
1162       phdr.p_filesz = 0;
1163       phdr.p_offset = 0;
1164     }
1165     if (!writea(1, &phdr, sizeof(phdr)))
1166       return 1;
1167   }
1168 
1169   Nhdr nhdr;
1170   memset(&nhdr, 0, sizeof(nhdr));
1171   nhdr.n_namesz = 5;
1172   nhdr.n_descsz = sizeof(prpsinfo);
1173   nhdr.n_type = NT_PRPSINFO;
1174   if (!writea(1, &nhdr, sizeof(nhdr)) ||
1175       !writea(1, "CORE\0\0\0\0", 8) ||
1176       !writea(1, &crashinfo.prps, sizeof(prpsinfo))) {
1177     return 1;
1178   }
1179 
1180   nhdr.n_descsz = crashinfo.auxv_length;
1181   nhdr.n_type = NT_AUXV;
1182   if (!writea(1, &nhdr, sizeof(nhdr)) ||
1183       !writea(1, "CORE\0\0\0\0", 8) ||
1184       !writea(1, crashinfo.auxv, crashinfo.auxv_length)) {
1185     return 1;
1186   }
1187 
1188   for (unsigned i = 0; i < crashinfo.threads.size(); ++i) {
1189     if (crashinfo.threads[i].tid == crashinfo.crashing_tid) {
1190       WriteThread(crashinfo.threads[i], crashinfo.fatal_signal);
1191       break;
1192     }
1193   }
1194 
1195   for (unsigned i = 0; i < crashinfo.threads.size(); ++i) {
1196     if (crashinfo.threads[i].tid != crashinfo.crashing_tid)
1197       WriteThread(crashinfo.threads[i], 0);
1198   }
1199 
1200   if (note_align) {
1201     google_breakpad::scoped_array<char> scratch(new char[note_align]);
1202     memset(scratch.get(), 0, note_align);
1203     if (!writea(1, scratch.get(), note_align))
1204       return 1;
1205   }
1206 
1207   for (std::map<uint64_t, CrashedProcess::Mapping>::const_iterator iter =
1208          crashinfo.mappings.begin();
1209        iter != crashinfo.mappings.end(); ++iter) {
1210     const CrashedProcess::Mapping& mapping = iter->second;
1211     if (mapping.data.size()) {
1212       if (!writea(1, mapping.data.c_str(), mapping.data.size()))
1213         return 1;
1214     }
1215   }
1216 
1217   return 0;
1218 }
1219