static int wait_for_break (pid_t pid, struct user_regs_struct *state, int *status)
{
int ret;
if (ptrace (PTRACE_SYSCALL, pid, 0, 0) == -1)
return -1; // FAIL
if ((ret = wait_for_stopped (pid, true, status)))
return ret;
if (ptrace (PTRACE_GETREGS, pid, 0, state) == -1)
return -1;
return 0;
}
bool DFInstanceLinux::attach() {
TRACE << "STARTING ATTACH" << m_attach_count;
if (is_attached()) {
m_attach_count++;
TRACE << "ALREADY ATTACHED SKIPPING..." << m_attach_count;
return true;
}
if (ptrace(PTRACE_ATTACH, m_pid, 0, 0) == -1) { // unable to attach
perror("ptrace attach");
LOGE << "Could not attach to PID" << m_pid;
return false;
}
wait_for_stopped();
m_attach_count++;
TRACE << "FINISHED ATTACH" << m_attach_count;
return m_attach_count > 0;
}
int main (int argc, char *argv[])
{
pid_t pid;
int status = 1;
struct tracer *tracer = NULL;
struct process *process = NULL;
if (argc < 2)
return 1;
pid = fork ();
if (pid < 0)
{
perror ("fork");
return 2;
}
if (pid == 0)
fork_and_trace_child (argv);
if (wait_for_stopped (pid, false, &status))
{
fprintf (stderr, "child process unexpectedly dead\n");
return 3;
}
/*
When delivering syscall traps, set bit 7 in the signal number
(i.e., deliver SIGTRAP | 0x80). This makes it easy for the tracer
to tell the difference between normal traps and those caused by a
syscall. (PTRACE_O_TRACESYSGOOD may not work on all architectures.)
*/
if (ptrace (PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACESYSGOOD) == -1)
return 5;
status = 1;
if (!(tracer = tracer_alloc ()))
{
fprintf (stderr, "Can not allocate tracer\n");
goto end;
}
if (!(process = process_alloc (pid)))
{
fprintf (stderr, "Can not allocate process\n");
goto end;
}
if (tracer_add_process (tracer, process) == -1)
{
fprintf (stderr, "Cannot add process to tracer\n");
goto end;
}
/* process = NULL should be here (!) */
for (;;)
{
struct user_regs_struct state1;
struct user_regs_struct state2;
if (wait_for_break (pid, &state1, &status))
break;
if (wait_for_break (pid, &state2, &status))
break;
trace_syscall (process, &state1, &state2);
}
process = NULL;
status &= 0xff;
end:
if (process)
process_destroy (process);
if (tracer)
tracer_destroy (tracer);
return status;
}
