path: root/src/common/mac/dump_syms.mm

//
// Copyright (c) 2006, 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.

// dump_syms.mm: Create a symbol file for use with minidumps

#include <unistd.h>
#include <signal.h>

#include <mach/machine.h>
#include <mach-o/arch.h>
#include <mach-o/fat.h>
#include <mach-o/loader.h>
#include <mach-o/nlist.h>
#include <mach-o/stab.h>

#import <Foundation/Foundation.h>

#import "dump_syms.h"
#import "common/mac/file_id.h"

using google_airbag::FileID;

static NSString *kAddressSymbolKey = @"symbol";
static NSString *kAddressConvertedSymbolKey = @"converted_symbol";
static NSString *kAddressSourceLineKey = @"line";
static NSString *kFunctionSizeKey = @"size";
static NSString *kHeaderBaseAddressKey = @"baseAddr";
static NSString *kHeaderSizeKey = @"size";
static NSString *kHeaderOffsetKey = @"offset";  // Offset to the header
static NSString *kHeaderIs64BitKey = @"is64";
static NSString *kHeaderCPUTypeKey = @"cpuType";
static NSString *kUnknownSymbol = @"???";

@interface DumpSymbols(PrivateMethods)
- (NSString *)stringFromTask:(NSString *)action args:(NSArray *)args
                  standardIn:(NSFileHandle *)standardIn;
- (NSArray *)convertCPlusPlusSymbols:(NSArray *)symbols;
- (void)convertSymbols;
- (void)addFunction:(NSString *)name line:(int)line address:(uint64_t)address;
- (BOOL)processSymbolItem:(struct nlist_64 *)list stringTable:(char *)table;
- (BOOL)loadSymbolInfo:(void *)base offset:(uint32_t)offset;
- (BOOL)loadSymbolInfo64:(void *)base offset:(uint32_t)offset;
- (BOOL)loadSymbolInfoForArchitecture;
- (BOOL)loadHeader:(void *)base offset:(uint32_t)offset;
- (BOOL)loadHeader64:(void *)base offset:(uint32_t)offset;
- (BOOL)loadModuleInfo;
- (NSMutableString *)generateSymbolFileString;
@end

static BOOL StringHeadMatches(NSString *str, NSString *head) {
  int headLen = [head length];
  int strLen = [str length];

  if (headLen > strLen)
    return NO;

  return [[str substringToIndex:headLen] isEqualToString:head];
}

static BOOL StringTailMatches(NSString *str, NSString *tail) {
  int tailLen = [tail length];
  int strLen = [str length];

  if (tailLen > strLen)
    return NO;

  return [[str substringFromIndex:strLen - tailLen] isEqualToString:tail];
}

@implementation DumpSymbols
//=============================================================================
- (NSString *)stringFromTask:(NSString *)action args:(NSArray *)args
                  standardIn:(NSFileHandle *)standardIn {
  NSTask *task = [[NSTask alloc] init];
  [task setLaunchPath:action];
  NSPipe *pipe = [NSPipe pipe];
  [task setStandardOutput:pipe];
  NSFileHandle *output = [pipe fileHandleForReading];

  if (standardIn)
    [task setStandardInput:standardIn];

  if (args)
    [task setArguments:args];

  [task launch];

  // This seems a bit strange, but when using [task waitUntilExit], it hangs
  // waiting for data, but there isn't any.  So, we'll poll for data,
  // take a short nap, and then ask again
  BOOL done = NO;
  NSMutableData *allData = [NSMutableData data];
  NSData *data = nil;
  int exceptionCount = 0;

  while (!done) {
    data = nil;
    // If there's a communications problem with the task, this might throw
    // an exception.  We'll catch and keep trying.
    @try {
      data = [output availableData];
    }
    @catch (NSException *e) {
      ++exceptionCount;
    }

    [allData appendData:data];

    // Loop over the data until we're no longer returning data.  If we're
    // still receiving data, sleep for 1/2 second and let the task
    // continue.  If we keep receiving exceptions, bail out
    if (![data length] && data || exceptionCount > 10)
      done = YES;
    else
      usleep(500);
  }

  // Gather any remaining data
  [task waitUntilExit];
  data = [output availableData];
  [allData appendData:data];
  [task release];

  return [[[NSString alloc] initWithData:allData
                                encoding:NSUTF8StringEncoding] autorelease];
}

//=============================================================================
- (NSArray *)convertCPlusPlusSymbols:(NSArray *)symbols {
  NSString *action = @"/usr/bin/c++filt";
  unsigned int count = [symbols count];

  // It's possible that we have too many symbols on the command line.
  // Unfortunately, c++filt doesn't take a file containing names, so we'll
  // copy the symbols to a temporary file and use that as stdin.
  char buffer[PATH_MAX];
  snprintf(buffer, sizeof(buffer), "/tmp/dump_syms_filtXXXXX");
  int fd = mkstemp(buffer);
  char nl = '\n';
  for (unsigned int i = 0; i < count; ++i) {
    const char *symbol = [[symbols objectAtIndex:i] UTF8String];
    write(fd, symbol, strlen(symbol));
    write(fd, &nl, 1);
  }

  // Reset to the beginning and wrap up with a file handle
  lseek(fd, 0, SEEK_SET);
  NSArray *args = [NSArray arrayWithObject:@"-n"];
  NSFileHandle *fh = [[NSFileHandle alloc] initWithFileDescriptor:fd
                                                   closeOnDealloc:YES];
  NSArray *result = [[self stringFromTask:action args:args standardIn:fh]
      componentsSeparatedByString:@"\n"];

  [fh release];

  return result;
}

//=============================================================================
- (void)convertSymbols {
  unsigned int count = [cppAddresses_ count];
  NSMutableArray *symbols = [[NSMutableArray alloc] initWithCapacity:count];

  // Sort addresses for processing
  NSArray *addresses = [cppAddresses_ sortedArrayUsingSelector:
    @selector(compare:)];

  for (unsigned int i = 0; i < count; ++i) {
    NSMutableDictionary *dict = [addresses_ objectForKey:
      [addresses objectAtIndex:i]];
    NSString *symbol = [dict objectForKey:kAddressSymbolKey];

    // Make sure that the symbol is valid
    if ([symbol length] < 1)
      symbol = kUnknownSymbol;

    [symbols addObject:symbol];
  }

  NSArray *converted = [self convertCPlusPlusSymbols:symbols];
  [symbols release];

  for (unsigned int i = 0; i < count; ++i) {
    NSMutableDictionary *dict = [addresses_ objectForKey:
      [addresses objectAtIndex:i]];
    NSString *symbol = [converted objectAtIndex:i];

    // Only add if this is a non-zero length symbol
    if ([symbol length])
      [dict setObject:symbol forKey:kAddressConvertedSymbolKey];
  }
}

//=============================================================================
- (void)addFunction:(NSString *)name line:(int)line address:(uint64_t)address {
  NSNumber *addressNum = [NSNumber numberWithUnsignedLongLong:address];

  if (!address)
    return;

  // If the function starts with "_Z" or "__Z" then add it to the list of
  // addresses to run through the c++filt
  BOOL isCPP = NO;

  if (StringHeadMatches(name, @"__Z")) {
    // Remove the leading underscore
    name = [name substringFromIndex:1];
    isCPP = YES;
  } else if (StringHeadMatches(name, @"_Z")) {
    isCPP = YES;
  }

  // Filter out non-functions
  if (StringTailMatches(name, @".eh"))
    return;

  if (StringTailMatches(name, @"__func__"))
    return;

  if (StringTailMatches(name, @"GCC_except_table"))
    return;

  if (isCPP) {
    if (!cppAddresses_)
      cppAddresses_ = [[NSMutableArray alloc] init];
    [cppAddresses_ addObject:addressNum];
  } else if ([name characterAtIndex:0] == '_') {
    // Remove the leading underscore
    name = [name substringFromIndex:1];
  }

  // If there's already an entry for this address, check and see if we can add
  // either the symbol, or a missing line #
  NSMutableDictionary *dict = [addresses_ objectForKey:addressNum];

  if (!dict) {
    dict = [[NSMutableDictionary alloc] init];
    [addresses_ setObject:dict forKey:addressNum];
    [dict release];
  }

  if (name && ![dict objectForKey:kAddressSymbolKey])
    [dict setObject:name forKey:kAddressSymbolKey];

  if (line && ![dict objectForKey:kAddressSourceLineKey])
    [dict setObject:[NSNumber numberWithUnsignedInt:line]
             forKey:kAddressSourceLineKey];

  // Save the function name so that we can add the end of function address
  if ([name length])
    lastFunctionStart_ = addressNum;
}

//=============================================================================
- (BOOL)processSymbolItem:(struct nlist_64 *)list stringTable:(char *)table {
  uint32_t n_strx = list->n_un.n_strx;
  BOOL result = NO;

  // Extract debugging information:
  // Doc: http://developer.apple.com/documentation/DeveloperTools/gdb/stabs/stabs_toc.html
  // Header: /usr/include/mach-o/stab.h:
  if (list->n_type == N_SO)  {
    NSString *src = [NSString stringWithUTF8String:&table[n_strx]];
    NSString *ext = [src pathExtension];
    NSNumber *address = [NSNumber numberWithUnsignedLongLong:list->n_value];

    // TODO(waylonis):Ensure that we get the full path for the source file
    // from the first N_SO record
    // If there is an extension, we'll consider it source code
    if ([ext length]) {
      if (!sources_)
        sources_ = [[NSMutableDictionary alloc] init];
      // Save the source associated with an address
      [sources_ setObject:src forKey:address];

      result = YES;
    }
  } else if (list->n_type == N_FUN) {
    NSString *fn = [NSString stringWithUTF8String:&table[n_strx]];
    NSRange range = [fn rangeOfString:@":" options:NSBackwardsSearch];

    if (![fn length] || !range.length)
      return NO;

    // The function has a ":" followed by some stuff
    fn = [fn substringToIndex:range.location];
    [self addFunction:fn line:list->n_desc address:list->n_value];
    result = YES;
  } else if (list->n_type == N_SLINE) {
    [self addFunction:nil line:list->n_desc address:list->n_value];
    result = YES;
  } else if ((list->n_type & N_TYPE) == N_SECT &&
             !(list->n_type & N_STAB)) {
    // Regular symbols or ones that are external
    NSString *fn = [NSString stringWithUTF8String:&table[n_strx]];
    [self addFunction:fn line:0 address:list->n_value];
    result = YES;
  } else if (list->n_type == N_ENSYM) {
    // End of symbols for current function
    if (lastFunctionStart_) {
      unsigned long long start = [lastFunctionStart_ unsignedLongLongValue];
      unsigned long long size = list->n_value - start;
      NSMutableDictionary *dict = [addresses_ objectForKey:lastFunctionStart_];
      assert(dict);
      [dict setObject:[NSNumber numberWithUnsignedLongLong:size]
               forKey:kFunctionSizeKey];
    }
  }

  return result;
}

#define SwapLongLongIfNeeded(a) (swap ? NXSwapLongLong(a) : (a))
#define SwapLongIfNeeded(a) (swap ? NXSwapLong(a) : (a))
#define SwapIntIfNeeded(a) (swap ? NXSwapInt(a) : (a))
#define SwapShortIfNeeded(a) (swap ? NXSwapShort(a) : (a))
//=============================================================================
- (BOOL)loadSymbolInfo:(void *)base offset:(uint32_t)offset {
  struct mach_header *header = (struct mach_header *)((uint32_t)base + offset);
  BOOL swap = (header->magic == MH_CIGAM);
  uint32_t count = SwapLongIfNeeded(header->ncmds);
  struct load_command *cmd =
    (struct load_command *)((uint32_t)header + sizeof(struct mach_header));
  uint32_t symbolTableCommand = SwapLongIfNeeded(LC_SYMTAB);
  BOOL result = NO;

  if (!addresses_)
    addresses_ = [[NSMutableDictionary alloc] init];

  for (uint32_t i = 0; cmd && (i < count); i++) {
    if (cmd->cmd == symbolTableCommand) {
      struct symtab_command *symtab = (struct symtab_command *)cmd;
      uint32_t ncmds = SwapLongIfNeeded(symtab->nsyms);
      uint32_t symoff = SwapLongIfNeeded(symtab->symoff);
      uint32_t stroff = SwapLongIfNeeded(symtab->stroff);
      struct nlist *list = (struct nlist *)((uint32_t)base + symoff + offset);
      char *strtab = ((char *)header + stroff);

      // Process each command, looking for debugging stuff
      for (uint32_t j = 0; j < ncmds; ++j, ++list) {
        // Fill in an nlist_64 structure and process with that
        struct nlist_64 nlist64;
        nlist64.n_un.n_strx = SwapLongIfNeeded(list->n_un.n_strx);
        nlist64.n_type = list->n_type;
        nlist64.n_sect = list->n_sect;
        nlist64.n_desc = SwapIntIfNeeded(list->n_desc);
        nlist64.n_value = (uint64_t)SwapLongIfNeeded(list->n_value);

        if ([self processSymbolItem:&nlist64 stringTable:strtab])
          result = YES;
      }
    }

    uint32_t cmdSize = SwapLongIfNeeded(cmd->cmdsize);
    cmd = (struct load_command *)((uint32_t)cmd + cmdSize);
  }

  return result;
}

//=============================================================================
- (BOOL)loadSymbolInfo64:(void *)base offset:(uint32_t)offset {
  struct mach_header_64 *header = (struct mach_header_64 *)
    ((uint32_t)base + offset);
  BOOL swap = (header->magic == MH_CIGAM_64);
  uint32_t count = SwapLongIfNeeded(header->ncmds);
  struct load_command *cmd =
    (struct load_command *)((uint32_t)header + sizeof(struct mach_header));
  uint32_t symbolTableCommand = SwapLongIfNeeded(LC_SYMTAB);
  BOOL result = NO;

  for (uint32_t i = 0; cmd && (i < count); i++) {
    if (cmd->cmd == symbolTableCommand) {
      struct symtab_command *symtab = (struct symtab_command *)cmd;
      uint32_t ncmds = SwapLongIfNeeded(symtab->nsyms);
      uint32_t symoff = SwapLongIfNeeded(symtab->symoff);
      uint32_t stroff = SwapLongIfNeeded(symtab->stroff);
      struct nlist_64 *list = (struct nlist_64 *)((uint32_t)base + symoff);
      char *strtab = ((char *)header + stroff);

      // Process each command, looking for debugging stuff
      for (uint32_t j = 0; j < ncmds; ++j, ++list) {
        if (!(list->n_type & (N_STAB | N_TYPE)))
          continue;

        // Fill in an nlist_64 structure and process with that
        struct nlist_64 nlist64;
        nlist64.n_un.n_strx = SwapLongIfNeeded(list->n_un.n_strx);
        nlist64.n_type = list->n_type;
        nlist64.n_sect = list->n_sect;
        nlist64.n_desc = SwapIntIfNeeded(list->n_desc);
        nlist64.n_value = SwapLongLongIfNeeded(list->n_value);

        if ([self processSymbolItem:&nlist64 stringTable:strtab])
          result = YES;
      }
    }

    uint32_t cmdSize = SwapLongIfNeeded(cmd->cmdsize);
    cmd = (struct load_command *)((uint32_t)cmd + cmdSize);
  }

  return result;
}

//=============================================================================
- (BOOL)loadSymbolInfoForArchitecture {
  NSMutableData *data = [[NSMutableData alloc]
    initWithContentsOfMappedFile:sourcePath_];
  NSDictionary *headerInfo = [headers_ objectForKey:architecture_];
  void *base = [data mutableBytes];
  uint32_t offset =
    [[headerInfo objectForKey:kHeaderOffsetKey] unsignedLongValue];
  BOOL is64 = [[headerInfo objectForKey:kHeaderIs64BitKey] boolValue];
  BOOL result = is64 ? [self loadSymbolInfo64:base offset:offset] :
    [self loadSymbolInfo:base offset:offset];

  [data release];
  return result;
}

//=============================================================================
- (BOOL)loadHeader:(void *)base offset:(uint32_t)offset {
  struct mach_header *header = (struct mach_header *)((uint32_t)base + offset);
  BOOL swap = (header->magic == MH_CIGAM);
  uint32_t count = SwapLongIfNeeded(header->ncmds);
  struct load_command *cmd =
    (struct load_command *)((uint32_t)header + sizeof(struct mach_header));

  for (uint32_t i = 0; cmd && (i < count); i++) {
    uint32_t segmentCommand = SwapLongIfNeeded(LC_SEGMENT);
    if (cmd->cmd == segmentCommand) {
      struct segment_command *seg = (struct segment_command *)cmd;
      if (!strcmp(seg->segname, "__TEXT")) {
        uint32_t addr = SwapLongIfNeeded(seg->vmaddr);
        uint32_t size = SwapLongIfNeeded(seg->vmsize);
        cpu_type_t cpu = SwapIntIfNeeded(header->cputype);
        NSString *cpuStr = (cpu == CPU_TYPE_I386) ? @"x86" : @"ppc";

        [headers_ setObject:[NSDictionary dictionaryWithObjectsAndKeys:
          [NSNumber numberWithUnsignedLongLong:(uint64_t)addr],
          kHeaderBaseAddressKey,
          [NSNumber numberWithUnsignedLongLong:(uint64_t)size], kHeaderSizeKey,
          [NSNumber numberWithUnsignedLong:offset], kHeaderOffsetKey,
          [NSNumber numberWithBool:NO], kHeaderIs64BitKey,
          [NSNumber numberWithUnsignedLong:cpu], kHeaderCPUTypeKey,
          nil] forKey:cpuStr];

        return YES;
      }
    }

    uint32_t cmdSize = SwapLongIfNeeded(cmd->cmdsize);
    cmd = (struct load_command *)((uint32_t)cmd + cmdSize);
  }

  return NO;
}

//=============================================================================
- (BOOL)loadHeader64:(void *)base offset:(uint32_t)offset {
  struct mach_header_64 *header =
    (struct mach_header_64 *)((uint32_t)base + offset);
  BOOL swap = (header->magic == MH_CIGAM_64);
  uint32_t count = SwapLongIfNeeded(header->ncmds);
  struct load_command *cmd =
    (struct load_command *)((uint32_t)header + sizeof(struct mach_header_64));

  for (uint32_t i = 0; cmd && (i < count); i++) {
    uint32_t segmentCommand = SwapLongIfNeeded(LC_SEGMENT_64);
    if (cmd->cmd == segmentCommand) {
      struct segment_command_64 *seg = (struct segment_command_64 *)cmd;
      if (!strcmp(seg->segname, "__TEXT")) {
        uint64_t addr = SwapLongLongIfNeeded(seg->vmaddr);
        uint64_t size = SwapLongLongIfNeeded(seg->vmsize);
        cpu_type_t cpu = SwapIntIfNeeded(header->cputype);
        cpu &= (~CPU_ARCH_ABI64);
        NSString *cpuStr = (cpu == CPU_TYPE_I386) ? @"x86_64" : @"ppc64";

        [headers_ setObject:[NSDictionary dictionaryWithObjectsAndKeys:
          [NSNumber numberWithUnsignedLongLong:addr], kHeaderBaseAddressKey,
          [NSNumber numberWithUnsignedLongLong:size], kHeaderSizeKey,
          [NSNumber numberWithUnsignedLong:offset], kHeaderOffsetKey,
          [NSNumber numberWithBool:YES], kHeaderIs64BitKey,
          nil] forKey:cpuStr];
        return YES;
      }
    }

    uint32_t cmdSize = SwapLongIfNeeded(cmd->cmdsize);
    cmd = (struct load_command *)((uint32_t)cmd + cmdSize);
  }

  return NO;
}

//=============================================================================
- (BOOL)loadModuleInfo {
  uint64_t result = 0;
  NSMutableData *data = [[NSMutableData alloc]
    initWithContentsOfMappedFile:sourcePath_];
  void *bytes = [data mutableBytes];
  struct fat_header *fat = (struct fat_header *)bytes;

  if (!fat) {
    [data release];
    return 0;
  }

  // Gather some information based on the header
  BOOL isFat = fat->magic == FAT_MAGIC || fat->magic == FAT_CIGAM;
  BOOL is64 = fat->magic == MH_MAGIC_64 || fat->magic == MH_CIGAM_64;
  BOOL is32 = fat->magic == MH_MAGIC || fat->magic == MH_CIGAM;
  BOOL swap = fat->magic == FAT_CIGAM || fat->magic == MH_CIGAM_64 ||
    fat->magic == MH_CIGAM;

  if (!is64 && !is32 && !isFat) {
    [data release];
    return 0;
  }

  // Load any available architectures and save the information
  headers_ = [[NSMutableDictionary alloc] init];

  if (isFat) {
    struct fat_arch *archs =
      (struct fat_arch *)((uint32_t)fat + sizeof(struct fat_header));
    uint32_t count = SwapLongIfNeeded(fat->nfat_arch);

    for (uint32_t i = 0; i < count; ++i) {
      archs[i].cputype = SwapIntIfNeeded(archs[i].cputype);
      archs[i].cpusubtype = SwapIntIfNeeded(archs[i].cpusubtype);
      archs[i].offset = SwapLongIfNeeded(archs[i].offset);
      archs[i].size = SwapLongIfNeeded(archs[i].size);
      archs[i].align = SwapLongIfNeeded(archs[i].align);

      if (archs[i].cputype & CPU_ARCH_ABI64)
        result = [self loadHeader64:bytes offset:archs[i].offset];
      else
        result = [self loadHeader:bytes offset:archs[i].offset];
    }
  } else if (is32) {
    result = [self loadHeader:bytes offset:0];
  } else {
    result = [self loadHeader64:bytes offset:0];
  }

  [data release];
  return result;
}

//=============================================================================
static 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)outputSymbolFile:(int)fd {
  // Get the baseAddress for this architecture
  NSDictionary *archDict = [headers_ objectForKey:architecture_];
  NSNumber *baseAddressNum = [archDict objectForKey:kHeaderBaseAddressKey];
  uint64_t baseAddress =
    baseAddressNum ? [baseAddressNum unsignedLongLongValue] : 0;
  NSNumber *moduleSizeNum = [archDict objectForKey:kHeaderSizeKey];
  uint64_t moduleSize =
    moduleSizeNum ? [moduleSizeNum unsignedLongLongValue] : 0;

  lastFunctionStart_ = nil;

  // Gather the information
  [self loadSymbolInfoForArchitecture];
  [self convertSymbols];

  NSArray *sortedAddresses = [[addresses_ allKeys]
    sortedArrayUsingSelector:@selector(compare:)];

  // UUID
  FileID file_id([sourcePath_ fileSystemRepresentation]);
  unsigned char identifier[16];
  char identifierStr[40];
  const char *moduleName = [[sourcePath_ lastPathComponent] UTF8String];
  int cpu_type = [[archDict objectForKey:kHeaderCPUTypeKey] unsignedLongValue];
  if (file_id.MachoIdentifier(cpu_type, identifier)) {
    FileID::ConvertIdentifierToString(identifier, identifierStr,
                                      sizeof(identifierStr));
  }
  else {
    strlcpy(identifierStr, moduleName, sizeof(identifierStr));
  }

  // Remove the dashes from the string
  NSMutableString *compactedStr =
    [NSMutableString stringWithCString:identifierStr encoding:NSASCIIStringEncoding];
  [compactedStr replaceOccurrencesOfString:@"-" withString:@"" options:0
                                     range:NSMakeRange(0, [compactedStr length])];

  if (!WriteFormat(fd, "MODULE mac %s %s0 %s\n", [architecture_ UTF8String],
                   [compactedStr UTF8String], moduleName)) {
    return NO;
  }

  // Sources ordered by address
  NSArray *sources = [[sources_ allKeys]
    sortedArrayUsingSelector:@selector(compare:)];
  unsigned int sourceCount = [sources count];
  for (unsigned int i = 0; i < sourceCount; ++i) {
    NSString *file = [sources_ objectForKey:[sources objectAtIndex:i]];
    if (!WriteFormat(fd, "FILE %d %s\n", i + 1, [file UTF8String]))
      return NO;
  }

  // Symbols
  char terminatingChar = '\n';
  uint32_t fileIdx = 0, nextFileIdx = 0;
  uint64_t nextSourceFileAddress = 0;
  NSNumber *nextAddress;
  uint64_t nextAddressVal;
  unsigned int addressCount = [sortedAddresses count];

  for (unsigned int i = 0; i < addressCount; ++i) {
    NSNumber *address = [sortedAddresses objectAtIndex:i];
    uint64_t addressVal = [address unsignedLongLongValue] - baseAddress;

    // Get the next address to calculate the length
    if (i + 1 < addressCount) {
      nextAddress = [sortedAddresses objectAtIndex:i + 1];
      nextAddressVal = [nextAddress unsignedLongLongValue] - baseAddress;
    } else {
      nextAddressVal = baseAddress + moduleSize;
      // The symbol reader doesn't want a trailing newline
      terminatingChar = '\0';
    }

    NSDictionary *dict = [addresses_ objectForKey:address];
    NSNumber *line = [dict objectForKey:kAddressSourceLineKey];
    NSString *symbol = [dict objectForKey:kAddressConvertedSymbolKey];

    if (!symbol)
      symbol = [dict objectForKey:kAddressSymbolKey];

    // Skip some symbols
    if (StringHeadMatches(symbol, @"__gnu"))
      continue;

    if (StringHeadMatches(symbol, @"typeinfo "))
      continue;

    if (StringHeadMatches(symbol, @"EH_frame"))
      continue;

    if (StringHeadMatches(symbol, @"GCC_except_table"))
      continue;

    // Find the source file (if any) that contains this address
    while (sourceCount && (addressVal >= nextSourceFileAddress)) {
      fileIdx = nextFileIdx;

      if (nextFileIdx < sourceCount) {
        NSNumber *addr = [sources objectAtIndex:nextFileIdx];
        ++nextFileIdx;
        nextSourceFileAddress = [addr unsignedLongLongValue] - baseAddress;
      } else {
        nextSourceFileAddress = baseAddress + moduleSize;
        break;
      }
    }

    if (line) {
      if (symbol) {
        NSNumber *functionLength = [dict objectForKey:kFunctionSizeKey];
        uint64_t functionLengthVal = [functionLength unsignedLongLongValue];

        // Function
        if (!WriteFormat(fd, "FUNC %llx %llx 0 %s\n", addressVal,
                         functionLengthVal, [symbol UTF8String]))
          return NO;
      }

      // Source line
      uint64_t length = nextAddressVal - addressVal;
      if (!WriteFormat(fd, "%llx %llx %d %d\n", addressVal, length,
                       [line unsignedIntValue], fileIdx))
        return NO;
    } else {
      // PUBLIC <address> <stack-size> <name>
      if (!WriteFormat(fd, "PUBLIC %llx 0 %s\n", addressVal,
                       [symbol UTF8String]))
        return NO;
    }
  }

  return YES;
}

//=============================================================================
- (id)initWithContentsOfFile:(NSString *)path {
  if ((self = [super init])) {

    if (![[NSFileManager defaultManager] fileExistsAtPath:path]) {
      [self autorelease];
      return nil;
    }

    sourcePath_ = [path copy];

    if (![self loadModuleInfo]) {
      [self autorelease];
      return nil;
    }

    // If there's more than one, use the native one
    if ([headers_ count] > 1) {
      const NXArchInfo *localArchInfo = NXGetLocalArchInfo();

      if (localArchInfo) {
        cpu_type_t cpu = localArchInfo->cputype;
        NSString *arch;

        if (cpu & CPU_ARCH_ABI64)
          arch = ((cpu & ~CPU_ARCH_ABI64) == CPU_TYPE_X86) ?
            @"x86_64" : @"ppc64";
        else
          arch = (cpu == CPU_TYPE_X86) ? @"x86" : @"ppc";

        [self setArchitecture:arch];
      }
    } else {
      // Specify the default architecture
      [self setArchitecture:[[headers_ allKeys] objectAtIndex:0]];
    }
  }

  return self;
}

//=============================================================================
- (NSArray *)availableArchitectures {
  return [headers_ allKeys];
}

//=============================================================================
- (void)dealloc {
  [sourcePath_ release];
  [architecture_ release];
  [addresses_ release];
  [sources_ release];
  [headers_ release];

  [super dealloc];
}

//=============================================================================
- (BOOL)setArchitecture:(NSString *)architecture {
  NSString *normalized = [architecture lowercaseString];
  BOOL isValid = NO;

  if ([normalized isEqualToString:@"ppc"]) {
    isValid = YES;
  }
  else if ([normalized isEqualToString:@"i386"]) {
    normalized = @"x86";
    isValid = YES;
  }
  else if ([normalized isEqualToString:@"x86"]) {
    isValid = YES;
  }
  else if ([normalized isEqualToString:@"ppc64"]) {
    isValid = YES;
  }
  else if ([normalized isEqualToString:@"x86_64"]) {
    isValid = YES;
  }

  if (isValid) {
    if (![headers_ objectForKey:normalized])
      return NO;

    [architecture_ autorelease];
    architecture_ = [architecture copy];
  }

  return isValid;
}

//=============================================================================
- (NSString *)architecture {
  return architecture_;
}

//=============================================================================
- (BOOL)writeSymbolFile:(NSString *)destinationPath {
  const char *dest = [destinationPath fileSystemRepresentation];
  int fd;

  if ([[destinationPath substringToIndex:1] isEqualToString:@"-"])
    fd = STDOUT_FILENO;
  else
    fd = open(dest, O_WRONLY | O_CREAT | O_TRUNC, 0666);

  if (fd == -1)
    return NO;

  BOOL result = [self outputSymbolFile:fd];

  close(fd);

  return result;
}

@end