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If the session leader dies, s_leader is set to NULL and getsid() may

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dereference a NULL pointer, causing a panic.  Instead of following
s_leader to find the session id, store it in the session structure.

Jukka found the following info:

	BTW - I just found what I have been looking for. Std 1003.1
	Part 1: SYSTEM API [C LANGUAGE] section 2.2.2.80 states quite
	explicitly...

	Session lifetime: The period between when a session is created
	and the end of lifetime of all the process groups that remain
	as members of the session.

	So, this quite clearly tells that while there is any single
	process in any process group which is a member of the session,
	the session remains as an independent entity.

Reviewed by:	peter
Submitted by:	"Jukka A. Ukkonen" <jau@jau.tmt.tele.fi>
This commit is contained in:
Don Lewis 1998-11-09 15:08:04 +00:00
parent 87bc830f60
commit 643a8daaaf
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=41038
4 changed files with 12 additions and 6 deletions
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8
sys/kern/kern_fork.c
View File

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)kern_fork.c 8.6 (Berkeley) 4/8/94
* $Id: kern_fork.c,v 1.50 1997/12/12 04:00:58 dyson Exp $
* $Id: kern_fork.c,v 1.51 1998/01/22 17:29:46 dyson Exp $
*/
#include "opt_ktrace.h"
@ -271,7 +271,8 @@ fork1(p1, flags)
again:
for (; p2 != 0; p2 = p2->p_list.le_next) {
while (p2->p_pid == nextpid ||
p2->p_pgrp->pg_id == nextpid) {
p2->p_pgrp->pg_id == nextpid ||
p2->p_session->s_sid == nextpid) {
nextpid++;
if (nextpid >= pidchecked)
goto retry;
@ -281,6 +282,9 @@ fork1(p1, flags)
if (p2->p_pgrp->pg_id > nextpid &&
pidchecked > p2->p_pgrp->pg_id)
pidchecked = p2->p_pgrp->pg_id;
if (p2->p_session->s_sid > nextpid &&
pidchecked > p2->p_session->s_sid)
pidchecked = p2->p_session->s_sid;
}
if (!doingzomb) {
doingzomb = 1;

3
sys/kern/kern_proc.c
View File

@ -31,7 +31,7 @@
* SUCH DAMAGE.
*
* @(#)kern_proc.c 8.7 (Berkeley) 2/14/95
* $Id: kern_proc.c,v 1.36 1998/02/20 13:52:14 bde Exp $
* $Id: kern_proc.c,v 1.37 1998/07/11 07:45:40 bde Exp $
*/
#include <sys/param.h>
@ -223,6 +223,7 @@ enterpgrp(p, pgid, mksess)
MALLOC(sess, struct session *, sizeof(struct session),
M_SESSION, M_WAITOK);
sess->s_leader = p;
sess->s_sid = p->p_pid;
sess->s_count = 1;
sess->s_ttyvp = NULL;
sess->s_ttyp = NULL;

4
sys/kern/kern_prot.c
View File

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)kern_prot.c 8.6 (Berkeley) 1/21/94
* $Id: kern_prot.c,v 1.39 1997/12/20 03:05:46 sef Exp $
* $Id: kern_prot.c,v 1.40 1998/06/10 10:28:29 dfr Exp $
*/
/*
@ -151,7 +151,7 @@ getsid(p, uap)
if ((p == pfind(uap->pid)) == 0)
return ESRCH;
found:
p->p_retval[0] = p->p_pgrp->pg_session->s_leader->p_pid;
p->p_retval[0] = p->p_session->s_sid;
return 0;
}

3
sys/sys/proc.h
View File

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)proc.h 8.15 (Berkeley) 5/19/95
* $Id: proc.h,v 1.57 1998/04/04 13:26:14 phk Exp $
* $Id: proc.h,v 1.58 1998/05/28 09:30:26 phk Exp $
*/
#ifndef _SYS_PROC_H_
@ -61,6 +61,7 @@ struct session {
struct proc *s_leader; /* Session leader. */
struct vnode *s_ttyvp; /* Vnode of controlling terminal. */
struct tty *s_ttyp; /* Controlling terminal. */
pid_t s_sid; /* Session ID */
char s_login[roundup(MAXLOGNAME, sizeof(long))]; /* Setlogin() name. */
};