get size of a loaded image

image_size.m

uint64_t get_image_size(struct mach_header_64 *mh) {
    struct load_command *cmd = (struct load_command *)((uint8_t *)mh + sizeof(struct mach_header_64));
    uint64_t max_addr = 0;
    for (uint32_t i = 0; i < mh->ncmds; i++) {
        if (cmd->cmd == LC_SEGMENT_64) {
            struct segment_command_64 *seg = (struct segment_command_64 *)cmd;
            uint64_t seg_end = seg->vmaddr + seg->vmsize;
            if (seg_end > max_addr) {
                max_addr = seg_end;
            }
        }
        cmd = (struct load_command *)((uint8_t *)cmd + cmd->cmdsize);
    }
    
    return max_addr - ((struct segment_command_64 *)((uint8_t *)mh + sizeof(struct mach_header_64)))->vmaddr;
}