How to get mach-o uuid of a running process? - iphone

Question

to get UUID on mac i can use
dwarfdump -u path/to/compile/executable
also i can get UUID with simple crash
in 'Binary Images' section
Is the way to get UUID without crash on ios device?

Answer 1

An executable's (mach-o file) UUID is created by the linker ld and is stored in a load command named LC_UUID. You can see all load commands of a mach-o file using otool:
otool -l path_to_executable
> ...
> Load command 8
> cmd LC_UUID
> cmdsize 24
> uuid 3AB82BF6-8F53-39A0-BE2D-D5AEA84D8BA6
> ...
Any process can access its mach-o header using a global symbol named _mh_execute_header. Using this symbol you can iterate over the load commands to search LC_UUID. The payload of the command is the UUID:
#import <mach-o/ldsyms.h>
NSString *executableUUID()
{
const uint8_t *command = (const uint8_t *)(&_mh_execute_header + 1);
for (uint32_t idx = 0; idx < _mh_execute_header.ncmds; ++idx) {
if (((const struct load_command *)command)->cmd == LC_UUID) {
command += sizeof(struct load_command);
return [NSString stringWithFormat:#"%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
command[0], command[1], command[2], command[3],
command[4], command[5],
command[6], command[7],
command[8], command[9],
command[10], command[11], command[12], command[13], command[14], command[15]];
} else {
command += ((const struct load_command *)command)->cmdsize;
}
}
return nil;
}