Function kern_ptrace

freebsd/kern/sys_process.c:604–1324

}

int
kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
{
	struct iovec iov;
	struct uio uio;
	struct proc *curp, *p, *pp;
	struct thread *td2 = NULL, *td3;
	struct ptrace_io_desc *piod = NULL;
	struct ptrace_lwpinfo *pl;
	struct ptrace_sc_ret *psr;
	int error, num, tmp;
	int proctree_locked = 0;
	lwpid_t tid = 0, *buf;
#ifdef COMPAT_FREEBSD32
	int wrap32 = 0, safe = 0;
#endif

	curp = td->td_proc;

	/* Lock proctree before locking the process. */
	switch (req) {
	case PT_TRACE_ME:
	case PT_ATTACH:
	case PT_STEP:
	case PT_CONTINUE:
	case PT_TO_SCE:
	case PT_TO_SCX:
	case PT_SYSCALL:
	case PT_FOLLOW_FORK:
	case PT_LWP_EVENTS:
	case PT_GET_EVENT_MASK:
	case PT_SET_EVENT_MASK:
	case PT_DETACH:
	case PT_GET_SC_ARGS:
		sx_xlock(&proctree_lock);
		proctree_locked = 1;
		break;
	default:
		break;
	}

	if (req == PT_TRACE_ME) {
		p = td->td_proc;
		PROC_LOCK(p);
	} else {
		if (pid <= PID_MAX) {
			if ((p = pfind(pid)) == NULL) {
				if (proctree_locked)
					sx_xunlock(&proctree_lock);
				return (ESRCH);
			}
		} else {
			td2 = tdfind(pid, -1);
			if (td2 == NULL) {
				if (proctree_locked)
					sx_xunlock(&proctree_lock);
				return (ESRCH);
			}