Allow debugger to specify that children of the traced process should be
automatically traced. Extend the ptrace(PL_LWPINFO) to report that child just forked. Reviewed by: davidxu, jhb MFC after: 2 weeks
This commit is contained in:
parent
f1d16bd892
commit
6fa39a7327
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=217819
@ -338,7 +338,7 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
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struct vmspace *vm2)
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{
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struct proc *p1, *pptr;
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int trypid;
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int p2_held, trypid;
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struct filedesc *fd;
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struct filedesc_to_leader *fdtol;
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struct sigacts *newsigacts;
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@ -346,6 +346,7 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
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sx_assert(&proctree_lock, SX_SLOCKED);
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sx_assert(&allproc_lock, SX_XLOCKED);
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p2_held = 0;
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p1 = td->td_proc;
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/*
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@ -632,6 +633,8 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
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PROC_SLOCK(p2);
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p2->p_state = PRS_NORMAL;
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PROC_SUNLOCK(p2);
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PROC_LOCK(p1);
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#ifdef KDTRACE_HOOKS
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/*
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* Tell the DTrace fasttrap provider about the new process
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@ -640,19 +643,33 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
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* later on.
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*/
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if (dtrace_fasttrap_fork) {
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PROC_LOCK(p1);
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PROC_LOCK(p2);
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dtrace_fasttrap_fork(p1, p2);
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PROC_UNLOCK(p2);
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PROC_UNLOCK(p1);
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}
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#endif
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/*
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* If RFSTOPPED not requested, make child runnable and add to
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* run queue.
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*/
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if ((p1->p_flag & (P_TRACED | P_FOLLOWFORK)) == (P_TRACED |
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P_FOLLOWFORK)) {
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/*
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* Arrange for debugger to receive the fork event.
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*
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* We can report PL_FLAG_FORKED regardless of
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* P_FOLLOWFORK settings, but it does not make a sense
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* for runaway child.
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*/
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td->td_dbgflags |= TDB_FORK;
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td->td_dbg_forked = p2->p_pid;
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PROC_LOCK(p2);
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td2->td_dbgflags |= TDB_STOPATFORK;
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_PHOLD(p2);
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p2_held = 1;
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PROC_UNLOCK(p2);
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}
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if ((flags & RFSTOPPED) == 0) {
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/*
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* If RFSTOPPED not requested, make child runnable and
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* add to run queue.
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*/
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thread_lock(td2);
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TD_SET_CAN_RUN(td2);
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sched_add(td2, SRQ_BORING);
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@ -662,7 +679,6 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
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/*
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* Now can be swapped.
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*/
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PROC_LOCK(p1);
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_PRELE(p1);
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PROC_UNLOCK(p1);
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@ -672,12 +688,20 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
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knote_fork(&p1->p_klist, p2->p_pid);
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SDT_PROBE(proc, kernel, , create, p2, p1, flags, 0, 0);
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/*
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* Wait until debugger is attached to child.
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*/
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PROC_LOCK(p2);
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while ((td2->td_dbgflags & TDB_STOPATFORK) != 0)
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cv_wait(&p2->p_dbgwait, &p2->p_mtx);
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if (p2_held)
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_PRELE(p2);
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/*
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* Preserve synchronization semantics of vfork. If waiting for
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* child to exec or exit, set P_PPWAIT on child, and sleep on our
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* proc (in case of exit).
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*/
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PROC_LOCK(p2);
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while (p2->p_flag & P_PPWAIT)
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cv_wait(&p2->p_pwait, &p2->p_mtx);
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PROC_UNLOCK(p2);
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@ -883,8 +907,37 @@ fork_exit(void (*callout)(void *, struct trapframe *), void *arg,
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void
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fork_return(struct thread *td, struct trapframe *frame)
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{
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struct proc *p, *dbg;
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if (td->td_dbgflags & TDB_STOPATFORK) {
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p = td->td_proc;
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sx_xlock(&proctree_lock);
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PROC_LOCK(p);
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if ((p->p_pptr->p_flag & (P_TRACED | P_FOLLOWFORK)) ==
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(P_TRACED | P_FOLLOWFORK)) {
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/*
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* If debugger still wants auto-attach for the
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* parent's children, do it now.
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*/
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dbg = p->p_pptr->p_pptr;
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p->p_flag |= P_TRACED;
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p->p_oppid = p->p_pptr->p_pid;
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proc_reparent(p, dbg);
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sx_xunlock(&proctree_lock);
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ptracestop(td, SIGSTOP);
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} else {
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/*
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* ... otherwise clear the request.
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*/
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sx_xunlock(&proctree_lock);
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td->td_dbgflags &= ~TDB_STOPATFORK;
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cv_broadcast(&p->p_dbgwait);
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}
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PROC_UNLOCK(p);
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}
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userret(td, frame);
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#ifdef KTRACE
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if (KTRPOINT(td, KTR_SYSRET))
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ktrsysret(SYS_fork, 0, 0);
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@ -230,6 +230,7 @@ proc_init(void *mem, int size, int flags)
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mtx_init(&p->p_mtx, "process lock", NULL, MTX_DEF | MTX_DUPOK);
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mtx_init(&p->p_slock, "process slock", NULL, MTX_SPIN | MTX_RECURSE);
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cv_init(&p->p_pwait, "ppwait");
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cv_init(&p->p_dbgwait, "dbgwait");
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TAILQ_INIT(&p->p_threads); /* all threads in proc */
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EVENTHANDLER_INVOKE(process_init, p);
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p->p_stats = pstats_alloc();
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@ -2393,6 +2393,10 @@ ptracestop(struct thread *td, int sig)
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p->p_xthread = td;
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p->p_flag |= (P_STOPPED_SIG|P_STOPPED_TRACE);
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sig_suspend_threads(td, p, 0);
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if ((td->td_dbgflags & TDB_STOPATFORK) != 0) {
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td->td_dbgflags &= ~TDB_STOPATFORK;
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cv_broadcast(&p->p_dbgwait);
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}
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stopme:
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thread_suspend_switch(td);
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if (!(p->p_flag & P_TRACED)) {
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@ -392,9 +392,9 @@ syscallret(struct thread *td, int error, struct syscall_args *sa __unused)
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*/
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STOPEVENT(p, S_SCX, sa->code);
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PTRACESTOP_SC(p, td, S_PT_SCX);
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if (traced || (td->td_dbgflags & TDB_EXEC) != 0) {
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if (traced || (td->td_dbgflags & (TDB_EXEC | TDB_FORK)) != 0) {
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PROC_LOCK(p);
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td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC);
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td->td_dbgflags &= ~(TDB_SCX | TDB_EXEC | TDB_FORK);
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PROC_UNLOCK(p);
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}
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}
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@ -94,6 +94,7 @@ struct ptrace_lwpinfo32 {
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sigset_t pl_siglist; /* LWP pending signal */
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struct siginfo32 pl_siginfo; /* siginfo for signal */
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char pl_tdname[MAXCOMLEN + 1]; /* LWP name. */
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int pl_child_pid; /* New child pid */
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};
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#endif
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@ -476,6 +477,7 @@ ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
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pl32->pl_siglist = pl->pl_siglist;
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siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
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strcpy(pl32->pl_tdname, pl->pl_tdname);
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pl32->pl_child_pid = pl->pl_child_pid;
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}
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#endif /* COMPAT_FREEBSD32 */
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@ -657,6 +659,7 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
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case PT_TO_SCE:
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case PT_TO_SCX:
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case PT_SYSCALL:
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case PT_FOLLOW_FORK:
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case PT_DETACH:
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sx_xlock(&proctree_lock);
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proctree_locked = 1;
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@ -852,6 +855,13 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
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td2->td_dbgflags &= ~TDB_SUSPEND;
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break;
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case PT_FOLLOW_FORK:
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if (data)
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p->p_flag |= P_FOLLOWFORK;
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else
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p->p_flag &= ~P_FOLLOWFORK;
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break;
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case PT_STEP:
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case PT_CONTINUE:
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case PT_TO_SCE:
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@ -912,7 +922,7 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
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if (pp == initproc)
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p->p_sigparent = SIGCHLD;
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}
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p->p_flag &= ~(P_TRACED | P_WAITED);
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p->p_flag &= ~(P_TRACED | P_WAITED | P_FOLLOWFORK);
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p->p_oppid = 0;
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/* should we send SIGCHLD? */
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@ -1118,6 +1128,10 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
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pl->pl_flags |= PL_FLAG_SCX;
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if (td2->td_dbgflags & TDB_EXEC)
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pl->pl_flags |= PL_FLAG_EXEC;
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if (td2->td_dbgflags & TDB_FORK) {
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pl->pl_flags |= PL_FLAG_FORKED;
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pl->pl_child_pid = td2->td_dbg_forked;
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}
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pl->pl_sigmask = td2->td_sigmask;
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pl->pl_siglist = td2->td_siglist;
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strcpy(pl->pl_tdname, td2->td_name);
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@ -265,6 +265,7 @@ struct thread {
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int td_ng_outbound; /* (k) Thread entered ng from above. */
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struct osd td_osd; /* (k) Object specific data. */
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struct vm_map_entry *td_map_def_user; /* (k) Deferred entries. */
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pid_t td_dbg_forked; /* (c) Child pid for debugger. */
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#define td_endzero td_rqindex
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/* Copied during fork1() or thread_sched_upcall(). */
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@ -374,6 +375,10 @@ do { \
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#define TDB_SCE 0x00000008 /* Thread performs syscall enter */
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#define TDB_SCX 0x00000010 /* Thread performs syscall exit */
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#define TDB_EXEC 0x00000020 /* TDB_SCX from exec(2) family */
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#define TDB_FORK 0x00000040 /* TDB_SCX from fork(2) that created new
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process */
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#define TDB_STOPATFORK 0x00000080 /* Stop at the return from fork (child
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only) */
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/*
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* "Private" flags kept in td_pflags:
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@ -557,7 +562,9 @@ struct proc {
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STAILQ_HEAD(, ktr_request) p_ktr; /* (o) KTR event queue. */
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LIST_HEAD(, mqueue_notifier) p_mqnotifier; /* (c) mqueue notifiers.*/
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struct kdtrace_proc *p_dtrace; /* (*) DTrace-specific data. */
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struct cv p_pwait; /* (*) wait cv for exit/exec */
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struct cv p_pwait; /* (*) wait cv for exit/exec. */
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struct cv p_dbgwait; /* (*) wait cv for debugger attach
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after fork. */
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};
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#define p_session p_pgrp->pg_session
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@ -573,7 +580,7 @@ struct proc {
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#define P_ADVLOCK 0x00001 /* Process may hold a POSIX advisory lock. */
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#define P_CONTROLT 0x00002 /* Has a controlling terminal. */
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#define P_KTHREAD 0x00004 /* Kernel thread (*). */
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#define P_UNUSED0 0x00008 /* available. */
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#define P_FOLLOWFORK 0x00008 /* Attach parent debugger to children. */
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#define P_PPWAIT 0x00010 /* Parent is waiting for child to exec/exit. */
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#define P_PROFIL 0x00020 /* Has started profiling. */
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#define P_STOPPROF 0x00040 /* Has thread requesting to stop profiling. */
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@ -63,6 +63,8 @@
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#define PT_TO_SCX 21
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#define PT_SYSCALL 22
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#define PT_FOLLOW_FORK 23
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#define PT_GETREGS 33 /* get general-purpose registers */
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#define PT_SETREGS 34 /* set general-purpose registers */
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#define PT_GETFPREGS 35 /* get floating-point registers */
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@ -104,10 +106,12 @@ struct ptrace_lwpinfo {
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#define PL_FLAG_SCX 0x08 /* syscall leave point */
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#define PL_FLAG_EXEC 0x10 /* exec(2) succeeded */
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#define PL_FLAG_SI 0x20 /* siginfo is valid */
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#define PL_FLAG_FORKED 0x40 /* new child */
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sigset_t pl_sigmask; /* LWP signal mask */
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sigset_t pl_siglist; /* LWP pending signal */
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struct __siginfo pl_siginfo; /* siginfo for signal */
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char pl_tdname[MAXCOMLEN + 1]; /* LWP name */
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int pl_child_pid; /* New child pid */
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};
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/* Argument structure for PT_VM_ENTRY. */
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