aboutsummaryrefslogtreecommitdiff
path: root/src/common/solaris/dump_symbols.cc
blob: b9fc74f609a905a5a63d3f18a46dbffdf948eefd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
// Copyright (c) 2007, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// Author: Alfred Peng

#include <demangle.h>
#include <fcntl.h>
#include <gelf.h>
#include <link.h>
#include <sys/mman.h>
#include <stab.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include <functional>
#include <vector>

#include "common/solaris/dump_symbols.h"
#include "common/solaris/file_id.h"
#include "common/solaris/guid_creator.h"
#include "processor/scoped_ptr.h"

// This namespace contains helper functions.
namespace {

// Symbol table entry for stabs. Sun CC specific.
struct slist {
  // String table index.
  unsigned int n_strx;
  // Stab type. 
  unsigned char n_type;
  char n_other;
  short n_desc;
  unsigned long n_value;
};

// Infomation of a line.
struct LineInfo {
  // Offset from start of the function.
  // Load from stab symbol.
  GElf_Off rva_to_func;
  // Offset from base of the loading binary.
  GElf_Off rva_to_base;
  // Size of the line.
  // The first line: equals to rva_to_func.
  // The other lines: the difference of rva_to_func of the line and
  // rva_to_func of the previous N_SLINE.
  uint32_t size;
  // Line number.
  uint32_t line_num;
};

// Information of a function.
struct FuncInfo {
  // Name of the function.
  const char *name;
  // Offset from the base of the loading address.
  GElf_Off rva_to_base;
  // Virtual address of the function.
  // Load from stab symbol.
  GElf_Addr addr;
  // Size of the function.
  // Equal to rva_to_func of the last function line.
  uint32_t size;
  // Total size of stack parameters.
  uint32_t stack_param_size;
  // Line information array.
  std::vector<struct LineInfo> line_info;
};

// Information of a source file.
struct SourceFileInfo {
  // Name of the source file.
  const char *name;
  // Starting address of the source file.
  GElf_Addr addr;
  // Id of the source file.
  int source_id;
  // Functions information.
  std::vector<struct FuncInfo> func_info;
};

// Information of a symbol table.
// This is the root of all types of symbol.
struct SymbolInfo {
  std::vector<struct SourceFileInfo> source_file_info;
};

// Stab section name.
const char *kStabName = ".stab";

// Stab str section name.
const char *kStabStrName = ".stabstr";

// Default buffer lenght for demangle.
const int demangleLen = 2000;

// Demangle using demangle library on Solaris.
std::string Demangle(const char *mangled) {
  int status = 0;
  char *demangled = (char *)malloc(demangleLen);
  if (!demangled) {
    fprintf(stderr, "no enough memory.\n");
    goto out;
  }

  if ((status = cplus_demangle(mangled, demangled, demangleLen)) ==
      DEMANGLE_ESPACE) {
    fprintf(stderr, "incorrect demangle.\n");
    goto out;
  }

  std::string str(demangled);
  free(demangled);
  return str;

out:
  return std::string(mangled);
}

// Find the prefered loading address of the binary.
GElf_Addr GetLoadingAddress(const GElf_Phdr *program_headers, int nheader) {
  for (int i = 0; i < nheader; ++i) {
    const GElf_Phdr &header = program_headers[i];
    // For executable, it is the PT_LOAD segment with offset to zero.
    if (header.p_type == PT_LOAD && header.p_offset == 0)
      return header.p_vaddr;
  }
  // For other types of ELF, return 0.
  return 0;
}

bool WriteFormat(int fd, const char *fmt, ...) {
  va_list list;
  char buffer[4096];
  ssize_t expected, written;
  va_start(list, fmt);
  vsnprintf(buffer, sizeof(buffer), fmt, list);
  expected = strlen(buffer);
  written = write(fd, buffer, strlen(buffer));
  va_end(list);
  return expected == written;
}

bool IsValidElf(const GElf_Ehdr *elf_header) {
  return memcmp(elf_header, ELFMAG, SELFMAG) == 0;
}

static bool FindSectionByName(Elf *elf, const char *name,
                              int shstrndx,
                              GElf_Shdr *shdr) {
  assert(name != NULL);

  if (strlen(name) == 0)
    return false;

  Elf_Scn *scn = NULL;

  while ((scn = elf_nextscn(elf, scn)) != NULL) {
    if (gelf_getshdr(scn, shdr) == (GElf_Shdr *)0) {
      fprintf(stderr, "failed to read section header: %s\n", elf_errmsg(0));
      return false;
    }

    const char *section_name = elf_strptr(elf, shstrndx, shdr->sh_name);
    if (!section_name) {
      fprintf(stderr, "Section name error: %s\n", elf_errmsg(-1));
      continue;
    }

    if (strcmp(section_name, name) == 0)
      return true;
  }

  return false;
}

// The parameter size is used for FPO-optimized code, and
// this is all tied up with the debugging data for Windows x86.
// Set it to 0 on Solaris.
int LoadStackParamSize(struct slist *list,
                       struct slist *list_end,
                       struct FuncInfo *func_info) {
  struct slist *cur_list = list;
  int step = 1;
  while (cur_list < list_end && cur_list->n_type == N_PSYM) {
    ++cur_list;
    ++step;
  }

  func_info->stack_param_size = 0;
  return step;
}

int LoadLineInfo(struct slist *list,
                 struct slist *list_end,
                 struct FuncInfo *func_info) {
  struct slist *cur_list = list;
  do {
    // Skip non line information.
    while (cur_list < list_end && cur_list->n_type != N_SLINE) {
      // Only exit when got another function, or source file.
      if (cur_list->n_type == N_FUN || cur_list->n_type == N_SO)
        return cur_list - list;
      ++cur_list;
    }
    struct LineInfo line;
    while (cur_list < list_end && cur_list->n_type == N_SLINE) {
      line.rva_to_func = cur_list->n_value;
      // n_desc is a signed short
      line.line_num = (unsigned short)cur_list->n_desc;
      func_info->line_info.push_back(line);
      ++cur_list;
    }
    if (cur_list == list_end && cur_list->n_type == N_ENDM)
      break;
  } while (list < list_end);

  return cur_list - list;
}

int LoadFuncSymbols(struct slist *list,
                    struct slist *list_end,
                    const GElf_Shdr *stabstr_section,
                    GElf_Word base,
                    struct SourceFileInfo *source_file_info) {
  struct slist *cur_list = list;
  assert(cur_list->n_type == N_SO);
  ++cur_list;

  source_file_info->func_info.clear();
  while (cur_list < list_end) {
    // Go until the function symbol.
    while (cur_list < list_end && cur_list->n_type != N_FUN) {
      if (cur_list->n_type == N_SO) {
        return cur_list - list;
      }
      ++cur_list;
      continue;
    }
    while (cur_list->n_type == N_FUN) {
      struct FuncInfo func_info;
      memset(&func_info, 0, sizeof(func_info));
      func_info.name =
        reinterpret_cast<char *>(cur_list->n_strx +
                                 stabstr_section->sh_offset + base);
      // The n_value field is always 0 from stab generated by Sun CC.
      // TODO(Alfred): Find the correct value.
      func_info.addr = cur_list->n_value;
      ++cur_list;
      if (cur_list->n_type != N_ESYM && cur_list->n_type != N_ISYM &&
          cur_list->n_type != N_FUN) {
        // Stack parameter size.
        cur_list += LoadStackParamSize(cur_list, list_end, &func_info);
        // Line info.
        cur_list += LoadLineInfo(cur_list, list_end, &func_info);
      }
      // Functions in this module should have address bigger than the module
      // starting address.
      //
      // These two values are always 0 with Sun CC.
      // TODO(Alfred): Get the correct value or remove the condition statement.
      if (func_info.addr >= source_file_info->addr) {
        source_file_info->func_info.push_back(func_info);
      }
    }
  }
  return cur_list - list;
}

// Compute size and rva information based on symbols loaded from stab section.
bool ComputeSizeAndRVA(GElf_Addr loading_addr, struct SymbolInfo *symbols) {
  std::vector<struct SourceFileInfo> *sorted_files =
    &(symbols->source_file_info);
  for (size_t i = 0; i < sorted_files->size(); ++i) {
    struct SourceFileInfo &source_file = (*sorted_files)[i];
    std::vector<struct FuncInfo> *sorted_functions = &(source_file.func_info);
    for (size_t j = 0; j < sorted_functions->size(); ++j) {
      struct FuncInfo &func_info = (*sorted_functions)[j];
      assert(func_info.addr >= loading_addr);
      func_info.rva_to_base = func_info.addr - loading_addr;
      int line_count = func_info.line_info.size();
      func_info.size =
        (line_count == 0) ? 0 :
                            func_info.line_info[line_count - 1].rva_to_func;
      // Compute function and line size.
      for (size_t k = 0; k < line_count; ++k) {
        struct LineInfo &line_info = func_info.line_info[k];
        if (k == 0) {
          line_info.size = line_info.rva_to_func;
        } else {
          line_info.size =
            line_info.rva_to_func - func_info.line_info[k - 1].rva_to_func;
        }
        line_info.rva_to_base = line_info.rva_to_func + func_info.rva_to_base;
      }  // for each line.
    }  // for each function.
  }  // for each source file.
  return true;
}

bool LoadAllSymbols(const GElf_Shdr *stab_section,
                    const GElf_Shdr *stabstr_section,
                    GElf_Addr loading_addr,
                    GElf_Word base,
                    struct SymbolInfo *symbols) {
  if (stab_section == NULL || stabstr_section == NULL)
    return false;

  struct slist *lists =
    reinterpret_cast<struct slist *>(stab_section->sh_offset + base);
  int nstab = stab_section->sh_size / sizeof(struct slist);
  int source_id = 0;
  // First pass, load all symbols from the object file.
  for (int i = 0; i < nstab; ) {
    int step = 1;
    struct slist *cur_list = lists + i;
    if (cur_list->n_type == N_SO) {
      // FUNC <address> <size> <param_stack_size> <function>
      struct SourceFileInfo source_file_info;
      source_file_info.name =
        reinterpret_cast<char *>(cur_list->n_strx +
                                 stabstr_section->sh_offset + base);
      // The n_value field is always 0 from stab generated by Sun CC.
      // TODO(Alfred): Find the correct value.
      source_file_info.addr = cur_list->n_value;
      if (strchr(source_file_info.name, '.'))
        source_file_info.source_id = source_id++;
      else
        source_file_info.source_id = -1;
      step = LoadFuncSymbols(cur_list, lists + nstab - 1,
                             stabstr_section, base, &source_file_info);
      symbols->source_file_info.push_back(source_file_info);
    }
    i += step;
  }
  // Second pass, compute the size of functions and lines.
  return ComputeSizeAndRVA(loading_addr, symbols);
}

bool LoadSymbols(Elf *elf, GElf_Ehdr *elf_header, struct SymbolInfo *symbols,
                 void *obj_base) {
  GElf_Word base = reinterpret_cast<GElf_Word>(obj_base);
  GElf_Addr loading_addr = GetLoadingAddress(
      reinterpret_cast<GElf_Phdr *>(elf_header->e_phoff + base),
      elf_header->e_phnum);

  const GElf_Shdr *sections =
    reinterpret_cast<GElf_Shdr *>(elf_header->e_shoff + base);
  GElf_Shdr stab_section;
  if (!FindSectionByName(elf, kStabName, elf_header->e_shstrndx,
                         &stab_section)) {
    fprintf(stderr, "Stab section not found.\n");
    return false;
  }
  GElf_Shdr stabstr_section;
  if (!FindSectionByName(elf, kStabStrName, elf_header->e_shstrndx,
                         &stabstr_section)) {
    fprintf(stderr, "Stabstr section not found.\n");
    return false;
  }

  // Load symbols.
  return LoadAllSymbols(&stab_section, &stabstr_section, loading_addr, base, symbols);
}

bool WriteModuleInfo(int fd, GElf_Half arch, const std::string &obj_file) {
  const char *arch_name = NULL;
  if (arch == EM_386)
    arch_name = "x86";
  else if (arch == EM_X86_64)
    arch_name = "x86_64";
  else
    return false;

  unsigned char identifier[16];
  google_breakpad::FileID file_id(obj_file.c_str());
  if (file_id.ElfFileIdentifier(identifier)) {
    char identifier_str[40];
    file_id.ConvertIdentifierToString(identifier,
                                      identifier_str, sizeof(identifier_str));
    std::string filename = obj_file;
    size_t slash_pos = obj_file.find_last_of("/");
    if (slash_pos != std::string::npos)
      filename = obj_file.substr(slash_pos + 1);
    return WriteFormat(fd, "MODULE solaris %s %s %s\n", arch_name,
                       identifier_str, filename.c_str());
  }
  return false;
}

bool WriteSourceFileInfo(int fd, const struct SymbolInfo &symbols) {
  for (size_t i = 0; i < symbols.source_file_info.size(); ++i) {
    if (symbols.source_file_info[i].source_id != -1) {
      const char *name = symbols.source_file_info[i].name;
      if (!WriteFormat(fd, "FILE %d %s\n",
                       symbols.source_file_info[i].source_id, name))
        return false;
    }
  }
  return true;
}

bool WriteOneFunction(int fd, int source_id,
                      const struct FuncInfo &func_info){
  // Discard the ending part of the name.
  std::string func_name(func_info.name);
  std::string::size_type last_colon = func_name.find_last_of(':');
  if (last_colon != std::string::npos)
    func_name = func_name.substr(0, last_colon);
  func_name = Demangle(func_name.c_str());

  if (func_info.size < 0)
    return true;

  // rva_to_base could be unsigned long(32 bit) or unsigned long long(64 bit).
  if (WriteFormat(fd, "FUNC %llx %d %d %s\n",
                  (long long)func_info.rva_to_base,
                  func_info.size,
                  func_info.stack_param_size,
                  func_name.c_str())) {
    for (size_t i = 0; i < func_info.line_info.size(); ++i) {
      const struct LineInfo &line_info = func_info.line_info[i];
      if (!WriteFormat(fd, "%llx %d %d %d\n",
                       (long long)line_info.rva_to_base,
                       line_info.size,
                       line_info.line_num,
                       source_id))
        return false;
    }
    return true;
  }
  return false;
}

bool WriteFunctionInfo(int fd, const struct SymbolInfo &symbols) {
  for (size_t i = 0; i < symbols.source_file_info.size(); ++i) {
    const struct SourceFileInfo &file_info = symbols.source_file_info[i];
    for (size_t j = 0; j < file_info.func_info.size(); ++j) {
      const struct FuncInfo &func_info = file_info.func_info[j];
      if (!WriteOneFunction(fd, file_info.source_id, func_info))
        return false;
    }
  }
  return true;
}

bool DumpStabSymbols(int fd, const struct SymbolInfo &symbols) {
  return WriteSourceFileInfo(fd, symbols) &&
    WriteFunctionInfo(fd, symbols);
}

//
// FDWrapper
//
// Wrapper class to make sure opened file is closed.
//
class FDWrapper {
 public:
  explicit FDWrapper(int fd) :
    fd_(fd) {
    }
  ~FDWrapper() {
    if (fd_ != -1)
      close(fd_);
  }
  int get() {
    return fd_;
  }
  int release() {
    int fd = fd_;
    fd_ = -1;
    return fd;
  }
 private:
  int fd_;
};

//
// MmapWrapper
//
// Wrapper class to make sure mapped regions are unmapped.
//
class MmapWrapper {
 public:
  MmapWrapper(void *mapped_address, size_t mapped_size) :
    base_(mapped_address), size_(mapped_size) {
  }
  ~MmapWrapper() {
    if (base_ != NULL) {
      assert(size_ > 0);
      munmap((char *)base_, size_);
    }
  }
  void release() {
    base_ = NULL;
    size_ = 0;
  }

 private:
  void *base_;
  size_t size_;
};

}  // namespace

namespace google_breakpad {

class AutoElfEnder {
 public:
  AutoElfEnder(Elf *elf) : elf_(elf) {}
  ~AutoElfEnder() { if (elf_) elf_end(elf_); }
 private:
  Elf *elf_;
};


bool DumpSymbols::WriteSymbolFile(const std::string &obj_file, int sym_fd) {
  if (elf_version(EV_CURRENT) == EV_NONE) {
    fprintf(stderr, "elf_version() failed: %s\n", elf_errmsg(0));
    return false;
  }

  int obj_fd = open(obj_file.c_str(), O_RDONLY);
  if (obj_fd < 0)
    return false;
  FDWrapper obj_fd_wrapper(obj_fd);
  struct stat st;
  if (fstat(obj_fd, &st) != 0 && st.st_size <= 0)
    return false;
  void *obj_base = mmap(NULL, st.st_size,
                        PROT_READ, MAP_PRIVATE, obj_fd, 0);
  if (!obj_base)
    return false;
  MmapWrapper map_wrapper(obj_base, st.st_size);
  GElf_Ehdr elf_header;
  Elf *elf = elf_begin(obj_fd, ELF_C_READ, NULL);
  AutoElfEnder elfEnder(elf);

  if (gelf_getehdr(elf, &elf_header) == (GElf_Ehdr *)NULL) {
    fprintf(stderr, "failed to read elf header: %s\n", elf_errmsg(-1));
    return false;
  }

  if (!IsValidElf(&elf_header)) {
    fprintf(stderr, "header magic doesn't match\n");
    return false;
  }
  struct SymbolInfo symbols;
  if (!LoadSymbols(elf, &elf_header, &symbols, obj_base))
    return false;
  // Write to symbol file.
  if (WriteModuleInfo(sym_fd, elf_header.e_machine, obj_file) &&
      DumpStabSymbols(sym_fd, symbols))
    return true;

  return false;
}

}  // namespace google_breakpad