change-bundle-id.m

// -*- c-basic-offset:2; tab-width:8; -*-
/*
 *  change-bundle-id.m
 *
 *  Created by Chris Suter on 16/5/2008.
 *  Copyright 2008 Coriolis Systems. All rights reserved.
 *
 */

#import <Foundation/Foundation.h>
#import <stdio.h>
#import <assert.h>
#import <mach-o/fat.h>
#import <mach-o/loader.h>
#import <libkern/OSByteOrder.h>
#import <sys/stat.h>
#import <sys/mman.h>

int main (int argc, const char * argv[]) 
{
  if (argc < 4) {
    printf ("usage: %s <file> <bundle ID> <bundle name>\n"
	    "       Updates the bundle ID held in Info.plist section of the mach-o file.\n",
	    argv[0]);
    return 1;
  }
  
  [[NSAutoreleasePool alloc] init];
  
  NSString *newID = [NSString stringWithUTF8String:argv[2]];
  NSString *newName = [NSString stringWithUTF8String:argv[3]];
  
  int fd = open (argv[1], O_RDWR);
  
  if (fd < 0) {
    fprintf (stderr, "Failed to open `%s'\n", argv[1]);
    return 1;
  }

  assert (fd >= 0);
  
  struct stat sb;
  
  if (fstat (fd, &sb) < 0) {
    fprintf (stderr, "fstat failed\n");
    return 1;
  }
  
  void *file = mmap (NULL, sb.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  
  if (!file) {
    fprintf (stderr, "mmap failed\n");
    return 1;
  }

  struct fat_header *fat_hdr = (struct fat_header *)file;
  
  struct mach_header *mach_hdr = NULL;
  unsigned num_archs, arch_ndx = 0;
  struct fat_arch *arch;
  unsigned num_done = 0;
  bool swap_mach;
  
  bool swap_fat = fat_hdr->magic != FAT_MAGIC;
  
  if (swap_fat && fat_hdr->magic != FAT_CIGAM) {
    // See if it's thin file...
    mach_hdr = (struct mach_header *)file;
    
    if (mach_hdr->magic != MH_MAGIC && mach_hdr->magic != MH_CIGAM) {
      fprintf (stderr, "Unexpected FAT or MACH-O header\n");
      return 1;
    }
    
    arch = NULL;
    num_archs = 1;
    goto thin_file;
  }
    
  num_archs = swap_fat ? OSSwapInt32 (fat_hdr->nfat_arch) : fat_hdr->nfat_arch;
  
  arch = (struct fat_arch *)&fat_hdr[1];
  
  for (arch_ndx = 0;
       arch_ndx < num_archs; 
       ++arch_ndx, ++arch) {
    mach_hdr = (struct mach_header *)((char *)file
				      + (swap_fat ? OSSwapInt32 (arch->offset) : arch->offset));
    
  thin_file:
    
    swap_mach = mach_hdr->magic != MH_MAGIC;
    
    if (swap_mach && mach_hdr->magic != MH_CIGAM) {
      fprintf (stderr, "Unexpected MACH-O header\n");
      return 1;
    }
    
    unsigned num_cmds = mach_hdr->ncmds;
    if (swap_mach)
      num_cmds = OSSwapInt32 (num_cmds);
    
    struct load_command *lc = (struct load_command *)&mach_hdr[1];
    unsigned cmd_size;
    
    for (unsigned cmd_ndx = 0; 
	 cmd_ndx < num_cmds; 
	 ++cmd_ndx, lc = (struct load_command *)((char *)lc + cmd_size)) {
      uint32_t cmd = swap_mach ? OSSwapInt32 (lc->cmd) : lc->cmd;
      cmd_size = swap_mach ? OSSwapInt32 (lc->cmdsize) : lc->cmdsize;
    
      if (cmd != LC_SEGMENT)
	continue;
     
      struct segment_command *sc = (struct segment_command *)lc;
      
      if (memcmp (sc->segname, "__TEXT", 7))
	continue;

      unsigned num_sects = swap_mach ? OSSwapInt32 (sc->nsects) : sc->nsects;
      
      struct section *sect = (struct section *)&sc[1];
      
      for (unsigned sect_ndx = 0; sect_ndx < num_sects; ++sect_ndx, ++sect) {
	if (memcmp (sect->sectname, "__info_plist", 13))
	  continue;
	
	uint32_t offset = swap_mach ? OSSwapInt32 (sect->offset) : sect->offset;
	uint32_t size = swap_mach ? OSSwapInt32 (sect->size) : sect->size;
	
	NSString *error;
	
	// Got it. Now read it in and parse it
	NSMutableDictionary *plist
	  = [NSPropertyListSerialization propertyListFromData:
	      [NSData dataWithBytesNoCopy:(char *)mach_hdr + offset
				   length:size
			     freeWhenDone:NO]
					     mutabilityOption:NSPropertyListMutableContainers
						       format:NULL
					     errorDescription:&error];
	if (!plist) {
	  fprintf (stderr, "Unable to parse property list\n");
	  return 1;
	}
      
	[plist setObject:newID forKey:(NSString *)kCFBundleIdentifierKey];
	[plist setObject:newName forKey:(NSString *)kCFBundleNameKey];
	
	NSData *d = [NSPropertyListSerialization dataFromPropertyList:plist
							       format:kCFPropertyListXMLFormat_v1_0 
						     errorDescription:&error];

	assert (d);
	if ([d length] > size) {
	  fprintf (stderr, "No room for new bundle ID\n");
	  return 1;
	}
	
	memcpy ((char *)mach_hdr + offset, [d bytes], [d length]);
	bzero ((char *)mach_hdr + offset + [d length], size - [d length]);
	sect->size = swap_mach ? OSSwapInt32 ([d length]) : [d length];
	++num_done;
	goto next_arch;
      } // for (...sect_ndx...)
    } // for (...cmd_ndx...)
  next_arch:
    ;
  } // for (...arch_ndx...)
  
  printf ("Updated bundle ID for %u archictecture(s)\n", num_done);
  
  return 0;
}