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Signals sent specifically to a particular thread must

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be delivered to that thread, regardless of whether it
has it masked or not.

Previously, if the targeted thread had the signal masked,
it would be put on the processes' siglist. If
another thread has the signal umasked or unmasks it before
the target, then the thread it was intended for would never
receive it.

This patch attempts to solve the problem by requiring callers
of tdsignal() to say whether the signal is for the thread or
for the process. If it is for the process, then normal processing
occurs and any thread that has it unmasked can receive it.
But if it is destined for a specific thread, it is put on
that thread's pending list regardless of whether it is currently
masked or not.

The new behaviour still needs more work, though.  If the signal
is reposted for some reason it is always posted back to the
thread that handled it because the information regarding the
target of the signal has been lost by then.

Reviewed by:	jdp, jeff, bde (style)
This commit is contained in:
mtm 2003-07-03 19:09:59 +00:00
parent 87561c3aaf
commit 6f4ee681fd
5 changed files with 25 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/kern/kern_kse.c
View File

@ -413,7 +413,7 @@ kse_thr_interrupt(struct thread *td, struct kse_thr_interrupt_args *uap)
if (sig > 0) {
td2->td_flags &= ~TDF_INTERRUPT;
mtx_unlock_spin(&sched_lock);
tdsignal(td2, sig);
tdsignal(td2, sig, SIGTARGET_P);
} else if (sig == 0) {
mtx_unlock_spin(&sched_lock);
} else {

26
sys/kern/kern_sig.c
View File

@ -95,7 +95,7 @@ static int filt_signal(struct knote *kn, long hint);
static struct thread *sigtd(struct proc *p, int sig, int prop);
static int kern_sigtimedwait(struct thread *td, sigset_t set,
siginfo_t *info, struct timespec *timeout);
static void do_tdsignal(struct thread *td, int sig);
static void do_tdsignal(struct thread *td, int sig, sigtarget_t target);
struct filterops sig_filtops =
{ 0, filt_sigattach, filt_sigdetach, filt_signal };
@ -761,7 +761,7 @@ sigwait(struct thread *td, struct sigwait_args *uap)
/* Repost if we got an error. */
if (error && info.si_signo) {
PROC_LOCK(td->td_proc);
tdsignal(td, info.si_signo);
tdsignal(td, info.si_signo, SIGTARGET_TD);
PROC_UNLOCK(td->td_proc);
}
return (error);
@ -800,7 +800,7 @@ sigtimedwait(struct thread *td, struct sigtimedwait_args *uap)
/* Repost if we got an error. */
if (error && info.si_signo) {
PROC_LOCK(td->td_proc);
tdsignal(td, info.si_signo);
tdsignal(td, info.si_signo, SIGTARGET_TD);
PROC_UNLOCK(td->td_proc);
} else {
td->td_retval[0] = info.si_signo;
@ -831,7 +831,7 @@ sigwaitinfo(struct thread *td, struct sigwaitinfo_args *uap)
/* Repost if we got an error. */
if (error && info.si_signo) {
PROC_LOCK(td->td_proc);
tdsignal(td, info.si_signo);
tdsignal(td, info.si_signo, SIGTARGET_TD);
PROC_UNLOCK(td->td_proc);
} else {
td->td_retval[0] = info.si_signo;
@ -1538,7 +1538,7 @@ trapsignal(struct thread *td, int sig, u_long code)
mtx_unlock(&ps->ps_mtx);
p->p_code = code; /* XXX for core dump/debugger */
p->p_sig = sig; /* XXX to verify code */
tdsignal(td, sig);
tdsignal(td, sig, SIGTARGET_TD);
}
PROC_UNLOCK(p);
}
@ -1607,21 +1607,21 @@ psignal(struct proc *p, int sig)
*/
td = sigtd(p, sig, prop);
tdsignal(td, sig);
tdsignal(td, sig, SIGTARGET_P);
}
/*
* MPSAFE
*/
void
tdsignal(struct thread *td, int sig)
tdsignal(struct thread *td, int sig, sigtarget_t target)
{
sigset_t saved;
struct proc *p = td->td_proc;
if (p->p_flag & P_SA)
saved = p->p_siglist;
do_tdsignal(td, sig);
do_tdsignal(td, sig, target);
if ((p->p_flag & P_SA) && !(p->p_flag & P_SIGEVENT)) {
if (SIGSETEQ(saved, p->p_siglist))
return;
@ -1634,7 +1634,7 @@ tdsignal(struct thread *td, int sig)
}
static void
do_tdsignal(struct thread *td, int sig)
do_tdsignal(struct thread *td, int sig, sigtarget_t target)
{
struct proc *p;
register sig_t action;
@ -1656,10 +1656,12 @@ do_tdsignal(struct thread *td, int sig)
/*
* If this thread is blocking this signal then we'll leave it in the
* proc so that we can find it in the first thread that unblocks it.
* proc so that we can find it in the first thread that unblocks
* it-- unless the signal is meant for the thread and not the process.
*/
if (SIGISMEMBER(td->td_sigmask, sig))
siglist = &p->p_siglist;
if (target == SIGTARGET_P)
siglist = SIGISMEMBER(td->td_sigmask, sig) ?
&p->p_siglist : &td->td_siglist;
else
siglist = &td->td_siglist;

6
sys/kern/kern_thr.c
View File

@ -258,11 +258,7 @@ thr_kill(struct thread *td, struct thr_kill_args *uap)
goto out;
}
/*
* We need a way to force this to go into this thread's siglist.
* Until then blocked signals will go to the proc.
*/
tdsignal(ttd, uap->sig);
tdsignal(ttd, uap->sig, SIGTARGET_TD);
out:
PROC_UNLOCK(p);

2
sys/kern/kern_thread.c
View File

@ -413,7 +413,7 @@ kse_thr_interrupt(struct thread *td, struct kse_thr_interrupt_args *uap)
if (sig > 0) {
td2->td_flags &= ~TDF_INTERRUPT;
mtx_unlock_spin(&sched_lock);
tdsignal(td2, sig);
tdsignal(td2, sig, SIGTARGET_P);
} else if (sig == 0) {
mtx_unlock_spin(&sched_lock);
} else {

9
sys/sys/signalvar.h
View File

@ -205,6 +205,13 @@ __sigseteq(sigset_t *set1, sigset_t *set2)
#ifdef _KERNEL
/*
* Specifies the target of a signal.
* P - Doesn't matter which thread it gets delivered to.
* TD - Must be delivered to a specific thread.
*/
typedef enum sigtarget_enum { SIGTARGET_P, SIGTARGET_TD } sigtarget_t;
/* Return nonzero if process p has an unmasked pending signal. */
#define SIGPENDING(td) \
(!SIGISEMPTY((td)->td_siglist) && \
@ -267,7 +274,7 @@ void sigexit(struct thread *td, int signum) __dead2;
int sig_ffs(sigset_t *set);
void siginit(struct proc *p);
void signotify(struct thread *td);
void tdsignal(struct thread *td, int sig);
void tdsignal(struct thread *td, int sig, sigtarget_t target);
void trapsignal(struct thread *td, int sig, u_long code);
/*