vm_write returns (os/kern) invalid address

I have did a self signed code codesign -- bu开发者_StackOverflow中文版t not sure why vm_write is failing.(I am using 10.6.6)

trying to figure out what is missing to make it work -- I appreciate some help of this issues.

#include <mach/vm_map.h>
#include <mach/mach_traps.h>
#include <mach/mach_error.h>

int main (int argc, const char * argv[])
{

    //get the task for PID
    kern_return_t err;
    int pid = 73002; // PID of process in the system
    mach_port_name_t t;


    err = task_for_pid(mach_task_self(), pid, &t);


    if(0 != err)
    {
        printf("task_for_pid : %s",mach_error_string(err));
    }

    vm_address_t address;
    vm_size_t size = 108;

    err =  vm_allocate(t,&address,size,TRUE);

    if(0 != err)
    {
        printf("vm_allocate : %s",mach_error_string(err));
    }

    vm_offset_t data = pid;
    mach_msg_type_number_t dataCnt = sizeof(pid);

    err = vm_write(t,address,data,dataCnt);

    if(0 != err)
    {
        printf("vm_write : %s",mach_error_string(err));
    }


    return 0;
}

Update:

1. self signed code codesign --- I have generated the certificate in the system and used for codesign.

2. vm_write returns (os/kern) invalid address (return value is "1")

You should be using the more-up-to-date mach_vm_address_t, mach_vm_size_t, mach_vm_allocate, mach_vm_offset_t, mach_vm_write(), etc. As far as I remember from experience, the older API's don't particularly work well on 64-bit processes (which can be quite relevant on 10.6). Also, use pid_t instead of int for the process ID.

The other poster is right that you're incorrectly passing the third argument to vm_write, and perhaps you want to pass &data, but you should be using mach_vm_write by the way. I'd expect your program to crash or try to write garbage with the way you were using vm_write, but the error returned seems to be KERN_INVALID_ADDRESS, which indicates that it failed writing to the memory address in the process.

I reckon you signed your code correctly if task_for_pid returns without errors. You should also use the constant KERN_SUCCESS, not 0 where appropriate.

The third argument of vm_write takes a pointer to a memory location (pointer_t), yet you pass the PID which simply isn't a valid memory location. You need to pass a correct memory location, like:

char *text = "123";
err = vm_write(t, address, text, strlen(text));

... which would pass the pointer to a static string.