Real-time collaboration for Jupyter Notebooks, Linux Terminals, LaTeX, VS Code, R IDE, and more,
all in one place.

1
//
2
//  main.m
3
//  flatten-macho
4
//
5
//  Created by qwertyoruiop on 4/6/17.
6
//  Copyright © 2017 qwertyoruiop. All rights reserved.
7
//
8

9
#import <Foundation/Foundation.h>
10
#import <mach-o/loader.h>
11
#import <fcntl.h>
12
#import <unistd.h>
13
#import <sys/stat.h>
14
#import <sys/mman.h>
15

16
int main(int argc, const char * argv[]) {
17
  if(argc != 3)
18
  {
19
    printf("usage: %s <input> <output>\n", argv[0]);
20
    return -1;
21
  }
22
  int fd = open(argv[1], O_RDONLY);
23
  int fd_w = open(argv[2], O_RDWR|O_CREAT|O_TRUNC, 0755);
24

25
  char header[0x4000];
26
  pread(fd, header, 0x4000, 0);
27

28
  struct mach_header_64* mh = header;
29
  uint64_t min = -1;
30
  uint64_t max = 0;
31
  struct load_command* lc = mh+1;
32
  for (int i = 0; i < mh->ncmds; i++) {
33
    if (lc->cmd == LC_SEGMENT_64)
34
    {
35
      struct segment_command_64* sg = lc;
36
      if (strcmp(sg->segname, "__PAGEZERO") != 0) {
37
        printf("segment %s\n", sg->segname);
38
        if (sg->vmaddr < min) min = sg->vmaddr;
39
        if (sg->vmaddr+sg->vmsize > max) max = sg->vmaddr+sg->vmsize;
40
      }
41
    }
42
    lc = (((char*)lc)+lc->cmdsize);
43
  }
44

45
  printf("found base: %llx, max: %llx\n", min, max);
46
  if(lseek(fd_w, max, SEEK_SET) == -1)
47
  {
48
    printf("seek failed\n");
49
    return -1;
50
  }
51

52
  lc = mh+1;
53
  for (int i = 0; i < mh->ncmds; i++) {
54
    if (lc->cmd == LC_SEGMENT_64)
55
    {
56
      struct segment_command_64* sg = lc;
57
      printf("mapping to %llx %llx %llx\n", sg->vmaddr, sg->fileoff, sg->filesize);
58

59
      if (sg->filesize == 0) {
60
        lc = (((char*)lc)+lc->cmdsize);
61
        continue;
62
      } // ignore pagezero
63
      char* map = mmap(0, sg->vmsize, PROT_READ, MAP_ANON|MAP_PRIVATE, -1, 0);
64
      if(mmap(map, sg->filesize, PROT_READ, MAP_FIXED|MAP_FILE|MAP_PRIVATE,fd,sg->fileoff) == MAP_FAILED)
65
      {
66
        printf("mmap failed\n");
67
        return -1;
68
      }
69
      printf("seeking to %llx\n", sg->vmaddr-min);
70
      lseek(fd_w, sg->vmaddr-min, SEEK_SET);
71
      write(fd_w, map, sg->vmsize);
72
      munmap(map, sg->vmsize);
73
    }
74
    lc = (((char*)lc)+lc->cmdsize);
75
  }
76

77
  return 0;
78
}
79

80

81