所以我意识到我可以在IDA Pro中打开一个二进制文件,并确定分段的开始/停止位置。有可能在运行时在Cocoa中确定吗?
我假设有一些启用此功能的c级库函数,我在mach标头中戳了一下,但找不到很多:/
提前致谢!
最佳答案
可可不包含用于处理Mach-O文件的类。您需要使用系统提供的Mach-O功能。您正确地阅读了Mach-O标头。
我编写了一个小程序,接受一个Mach-O文件名作为输入,并转储有关其分段的信息。请注意,此程序仅处理x86_64体系结构的精简文件(即非胖文件/通用文件)。
请注意,我也不会检查所有操作,也不检查文件是否是格式正确的Mach-O文件。做适当的检查留给读者练习。
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <mach-o/loader.h>
#include <sys/mman.h>
#include <sys/stat.h>
int main(int argc, char *argv[]) {
int fd;
struct stat stat_buf;
size_t size;
char *addr = NULL;
struct mach_header_64 *mh;
struct load_command *lc;
struct segment_command_64 *sc;
// Open the file and get its size
fd = open(argv[1], O_RDONLY);
fstat(fd, &stat_buf);
size = stat_buf.st_size;
// Map the file to memory
addr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_FILE | MAP_PRIVATE, fd, 0);
// The first bytes of a Mach-O file comprise its header
mh = (struct mach_header_64 *)addr;
// Load commands follow the header
addr += sizeof(struct mach_header_64);
printf("There are %d load commands\n", mh->ncmds);
for (int i = 0; i < mh->ncmds; i++) {
lc = (struct load_command *)addr;
if (lc->cmdsize == 0) continue;
// If the load command is a (64-bit) segment,
// print information about the segment
if (lc->cmd == LC_SEGMENT_64) {
sc = (struct segment_command_64 *)addr;
printf("Segment %s\n\t"
"vmaddr 0x%llx\n\t"
"vmsize 0x%llx\n\t"
"fileoff %llu\n\t"
"filesize %llu\n",
sc->segname,
sc->vmaddr,
sc->vmsize,
sc->fileoff,
sc->filesize);
}
// Advance to the next load command
addr += lc->cmdsize;
}
printf("\nDone.\n");
munmap(addr, size);
close(fd);
return 0;
}
您只需要针对x86_64位编译该程序,然后针对x86_64 Mach-O二进制文件运行它。例如,假设您已将该程序另存为test.c:
$ clang test.c -arch x86_64 -o test
$ ./test ./test
There are 11 load commands
Segment __PAGEZERO
vmaddr 0x0
vmsize 0x100000000
fileoff 0
filesize 0
Segment __TEXT
vmaddr 0x100000000
vmsize 0x1000
fileoff 0
filesize 4096
Segment __DATA
vmaddr 0x100001000
vmsize 0x1000
fileoff 4096
filesize 4096
Segment __LINKEDIT
vmaddr 0x100002000
vmsize 0x1000
fileoff 8192
filesize 624
Done.
如果您想获得更多有关如何读取Mach-O文件的示例,cctools on Apple’s Open Source Web site可能是最好的选择。您还需要阅读Mac OS X ABI Mach-O File Format Reference。