Linux 3.5.4 Ptrace (series Nine) __linux

This paper mainly analyzes the single step debugging function of Ptrace

The meaning of Single-step debugging I believe that we have been very clear, ptrace_singlestep parameters can be tracked by the program to step.

Ptrace_singlestep Restarts the stopped program so that it executes an instruction and then stops. We use the following code to verify this.

list11.c

#include "ptrace.h"
void main (int argc,char *argv[])
{
  pid_t child;
  int status,data;
  int trace_process;
  Trace_process=atoi (argv[1]);
  Track the target process, attach to stop the tracked process (stopped)

  Ptrace (ptrace_attach,trace_process,0,0);
  Wait (&status);

  Prints the signal information
  if (wifstopped (status) {
    printf ("The stopped by the attach!\n") that causes the trace process to stop;
    fprintf (stderr, "%s\n", Strsignal (Wstopsig (status));
  }

  Wakes the tracked process in Single-step mode, after the trace process executes an instruction and stops.
    Ptrace (ptrace_singlestep,trace_process,0,0);
    while (1) {
    //printf ("Just to-1!\n");

    When the tracked process is single-step, the trace process stops, and the wait is awakened by wait
    (&status);

    Out of Loop
    if (wifexited (status) {
      fprintf (stderr, "%s", Strsignal (Wexitstatus (status)) when the process is being tracked to exit;
      printf ("The Child is Exit!\n");
      break;
    else{

    Step, know i=10 this statement, and then replace I with 245.
     Data=ptrace (ptrace_peekdata,trace_process,0x08049764,0);
     if (data==10) {
        printf ("The data now is%d\n", data);
        data=245;
        Ptrace (ptrace_pokedata,trace_process,0x08049764,data);
        Ptrace (ptrace_cont,trace_process,0,0);
        break;
      }
    }
   Ptrace (ptrace_singlestep,trace_process,0,0);
  }

The wait wakes at the end of the child process. Wait
  (&status);
  if (wifexited (status)) {
    printf ("The" "the" is over!\n);
  }
}

#include "ptrace.h"
int i;
void Main ()
{sleep
  ();
  printf ("The Child is Start!\n");
  i=10;
  printf ("child5:i=%d\n", I);
}

1. Compiling two source files

2, in a terminal running CHILD5.O

3, in another terminal running LIST11.O (also can be on the same terminal)

The results of the operation are as follows