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- Lock proctree_lock instead of pgrpsess_lock.

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- Use temporary variables to hold a pointer to a pgrp while we dink with it
  while not holding either the associated proc lock or proctree_lock.  It
  is in theory possible that p->p_pgrp could change out from under us.
This commit is contained in:
John Baldwin 2002-04-16 17:09:22 +00:00
parent c8b1829d8e
commit 596325f154
2 changed files with 42 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

65
sys/kern/tty.c
View File

@ -731,6 +731,7 @@ ttioctl(tp, cmd, data, flag)
{
register struct proc *p;
struct thread *td;
struct pgrp *pgrp;
int s, error;
td = curthread; /* XXX */
@ -770,30 +771,30 @@ ttioctl(tp, cmd, data, flag)
case TIOCSETP:
case TIOCSLTC:
#endif
PGRPSESS_SLOCK();
sx_slock(&proctree_lock);
PROC_LOCK(p);
while (isbackground(p, tp) && !(p->p_flag & P_PPWAIT) &&
!SIGISMEMBER(p->p_sigignore, SIGTTOU) &&
!SIGISMEMBER(p->p_sigmask, SIGTTOU)) {
if (p->p_pgrp->pg_jobc == 0) {
pgrp = p->p_pgrp;
PROC_UNLOCK(p);
PGRPSESS_SUNLOCK();
if (pgrp->pg_jobc == 0) {
sx_sunlock(&proctree_lock);
return (EIO);
}
PROC_UNLOCK(p);
PGRP_LOCK(p->p_pgrp);
PGRPSESS_SUNLOCK();
pgsignal(p->p_pgrp, SIGTTOU, 1);
PGRP_UNLOCK(p->p_pgrp);
PGRP_LOCK(pgrp);
sx_sunlock(&proctree_lock);
pgsignal(pgrp, SIGTTOU, 1);
PGRP_UNLOCK(pgrp);
error = ttysleep(tp, &lbolt, TTOPRI | PCATCH, "ttybg1",
0);
if (error)
return (error);
PGRPSESS_SLOCK();
sx_slock(&proctree_lock);
PROC_LOCK(p);
}
PROC_UNLOCK(p);
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
break;
}
@ -1053,11 +1054,11 @@ ttioctl(tp, cmd, data, flag)
break;
case TIOCSCTTY: /* become controlling tty */
/* Session ctty vnode pointer set in vnode layer. */
PGRPSESS_SLOCK();
sx_slock(&proctree_lock);
if (!SESS_LEADER(p) ||
((p->p_session->s_ttyvp || tp->t_session) &&
(tp->t_session != p->p_session))) {
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
return (EPERM);
}
tp->t_session = p->p_session;
@ -1068,29 +1069,27 @@ ttioctl(tp, cmd, data, flag)
PROC_LOCK(p);
p->p_flag |= P_CONTROLT;
PROC_UNLOCK(p);
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
break;
case TIOCSPGRP: { /* set pgrp of tty */
register struct pgrp *pgrp;
PGRPSESS_SLOCK();
sx_slock(&proctree_lock);
pgrp = pgfind(*(int *)data);
if (!isctty(p, tp)) {
if (pgrp != NULL)
PGRP_UNLOCK(pgrp);
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
return (ENOTTY);
}
if (pgrp == NULL) {
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
return (EPERM);
}
PGRP_UNLOCK(pgrp);
if (pgrp->pg_session != p->p_session) {
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
return (EPERM);
}
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
tp->t_pgrp = pgrp;
break;
}
@ -1527,7 +1526,7 @@ ttymodem(tp, flag)
SET(tp->t_state, TS_ZOMBIE);
CLR(tp->t_state, TS_CONNECTED);
if (tp->t_session) {
PGRPSESS_SLOCK();
sx_slock(&proctree_lock);
if (tp->t_session->s_leader) {
struct proc *p;
@ -1536,7 +1535,7 @@ ttymodem(tp, flag)
psignal(p, SIGHUP);
PROC_UNLOCK(p);
}
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
}
ttyflush(tp, FREAD | FWRITE);
return (0);
@ -1601,6 +1600,7 @@ ttread(tp, uio, flag)
int has_stime = 0, last_cc = 0;
long slp = 0; /* XXX this should be renamed `timo'. */
struct timeval stime;
struct pgrp *pg;
loop:
s = spltty();
@ -1620,20 +1620,21 @@ ttread(tp, uio, flag)
*/
if (isbackground(p, tp)) {
splx(s);
PGRPSESS_SLOCK();
sx_slock(&proctree_lock);
PROC_LOCK(p);
if (SIGISMEMBER(p->p_sigignore, SIGTTIN) ||
SIGISMEMBER(p->p_sigmask, SIGTTIN) ||
(p->p_flag & P_PPWAIT) || p->p_pgrp->pg_jobc == 0) {
PROC_UNLOCK(p);
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
return (EIO);
}
pg = p->p_pgrp;
PROC_UNLOCK(p);
PGRP_LOCK(p->p_pgrp);
PGRPSESS_SUNLOCK();
pgsignal(p->p_pgrp, SIGTTIN, 1);
PGRP_UNLOCK(p->p_pgrp);
PGRP_LOCK(pg);
sx_sunlock(&proctree_lock);
pgsignal(pg, SIGTTIN, 1);
PGRP_UNLOCK(pg);
error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, "ttybg2", 0);
if (error)
return (error);
@ -1939,7 +1940,7 @@ ttwrite(tp, uio, flag)
* Hang the process if it's in the background.
*/
p = curproc;
PGRPSESS_SLOCK();
sx_slock(&proctree_lock);
PROC_LOCK(p);
if (isbackground(p, tp) &&
ISSET(tp->t_lflag, TOSTOP) && !(p->p_flag & P_PPWAIT) &&
@ -1947,13 +1948,13 @@ ttwrite(tp, uio, flag)
!SIGISMEMBER(p->p_sigmask, SIGTTOU)) {
if (p->p_pgrp->pg_jobc == 0) {
PROC_UNLOCK(p);
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
error = EIO;
goto out;
}
PROC_UNLOCK(p);
PGRP_LOCK(p->p_pgrp);
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
pgsignal(p->p_pgrp, SIGTTOU, 1);
PGRP_UNLOCK(p->p_pgrp);
error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, "ttybg4", 0);
@ -1962,7 +1963,7 @@ ttwrite(tp, uio, flag)
goto loop;
} else {
PROC_UNLOCK(p);
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
}
/*
* Process the user's data in at most OBUFSIZ chunks. Perform any

14
sys/kern/tty_pty.c
View File

@ -234,25 +234,27 @@ ptsread(dev, uio, flag)
struct proc *p = td->td_proc;
register struct tty *tp = dev->si_tty;
register struct pt_ioctl *pti = dev->si_drv1;
struct pgrp *pg;
int error = 0;
again:
if (pti->pt_flags & PF_REMOTE) {
while (isbackground(p, tp)) {
PGRPSESS_SLOCK();
sx_slock(&proctree_lock);
PROC_LOCK(p);
if (SIGISMEMBER(p->p_sigignore, SIGTTIN) ||
SIGISMEMBER(p->p_sigmask, SIGTTIN) ||
p->p_pgrp->pg_jobc == 0 || p->p_flag & P_PPWAIT) {
PROC_UNLOCK(p);
PGRPSESS_SUNLOCK();
sx_sunlock(&proctree_lock);
return (EIO);
}
pg = p->p_pgrp;
PROC_UNLOCK(p);
PGRP_LOCK(p->p_pgrp);
PGRPSESS_SUNLOCK();
pgsignal(p->p_pgrp, SIGTTIN, 1);
PGRP_UNLOCK(p->p_pgrp);
PGRP_LOCK(pg);
sx_sunlock(&proctree_lock);
pgsignal(pg, SIGTTIN, 1);
PGRP_UNLOCK(pg);
error = ttysleep(tp, &lbolt, TTIPRI | PCATCH, "ptsbg",
0);
if (error)