kernel/syscall/pgrpsys.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  27 /*        All Rights Reserved   */
  28
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"        /* from SVr4.0 1.78 */
  31
  32 #include <sys/param.h>
  33 #include <sys/types.h>
  34 #include <sys/sysmacros.h>
  35 #include <sys/systm.h>
  36 #include <sys/errno.h>
  37 #include <sys/file.h>
  38 #include <sys/proc.h>
  39 #include <sys/session.h>
  40 #include <sys/debug.h>
  41
  42 /* ARGSUSED */
  43 int
  44 setpgrp(int flag, int pid, int pgid)
  45 {
  46         proc_t  *p = curproc;
  47         int     retval = 0;
  48         int     sid;
  49
  50         switch (flag) {
  51
  52         case 1: /* setpgrp() */
  53                 mutex_enter(&pidlock);
  54                 if (p->p_sessp->s_sidp != p->p_pidp && !pgmembers(p->p_pid)) {
  55                         mutex_exit(&pidlock);
  56                         sess_create();
  57                 } else
  58                         mutex_exit(&pidlock);
  59                 mutex_enter(&p->p_splock);
  60                 sid = p->p_sessp->s_sid;
  61                 mutex_exit(&p->p_splock);
  62                 return (sid);
  63
  64         case 3: /* setsid() */
  65                 mutex_enter(&pidlock);
  66                 if (p->p_pgidp == p->p_pidp || pgmembers(p->p_pid)) {
  67                         mutex_exit(&pidlock);
  68                         return (set_errno(EPERM));
  69                 }
  70                 mutex_exit(&pidlock);
  71                 sess_create();
  72                 mutex_enter(&p->p_splock);
  73                 sid = p->p_sessp->s_sid;
  74                 mutex_exit(&p->p_splock);
  75                 return (sid);
  76
  77         case 5: /* setpgid() */
  78         {
  79                 mutex_enter(&pidlock);
  80                 if (pid == 0)
  81                         pid = p->p_pid;
  82                 else if (pid < 0 || pid >= maxpid) {
  83                         mutex_exit(&pidlock);
  84                         return (set_errno(EINVAL));
  85                 } else if (pid != p->p_pid) {
  86                         for (p = p->p_child; /* empty */; p = p->p_sibling) {
  87                                 if (p == NULL) {
  88                                         mutex_exit(&pidlock);
  89                                         return (set_errno(ESRCH));
  90                                 }
  91                                 if (p->p_pid == pid)
  92                                         break;
  93                         }
  94                         if (p->p_flag & SEXECED) {
  95                                 mutex_exit(&pidlock);
  96                                 return (set_errno(EACCES));
  97                         }
  98                         if (p->p_sessp != ttoproc(curthread)->p_sessp) {
  99                                 mutex_exit(&pidlock);
 100                                 return (set_errno(EPERM));
 101                         }
 102                 }
 103
 104                 if (p->p_sessp->s_sid == pid) {
 105                         mutex_exit(&pidlock);
 106                         return (set_errno(EPERM));
 107                 }
 108
 109                 if (pgid == 0)
 110                         pgid = p->p_pid;
 111                 else if (pgid < 0 || pgid >= maxpid) {
 112                         mutex_exit(&pidlock);
 113                         return (set_errno(EINVAL));
 114                 }
 115
 116                 if (p->p_pgrp == pgid) {
 117                         mutex_exit(&pidlock);
 118                         break;
 119                 } else if (p->p_pid == pgid) {
 120                         /*
 121                          * We need to protect p_pgidp with p_lock because
 122                          * /proc looks at it while holding only p_lock.
 123                          */
 124                         mutex_enter(&p->p_lock);
 125                         pgexit(p);
 126                         pgjoin(p, p->p_pidp);
 127                         mutex_exit(&p->p_lock);
 128                 } else {
 129                         register proc_t *q;
 130
 131                         if ((q = pgfind(pgid)) == NULL ||
 132                             q->p_sessp != p->p_sessp) {
 133                                 mutex_exit(&pidlock);
 134                                 return (set_errno(EPERM));
 135                         }
 136                         /*
 137                          * See comment above about p_lock and /proc
 138                          */
 139                         mutex_enter(&p->p_lock);
 140                         pgexit(p);
 141                         pgjoin(p, q->p_pgidp);
 142                         mutex_exit(&p->p_lock);
 143                 }
 144                 mutex_exit(&pidlock);
 145                 break;
 146         }
 147
 148         case 0: /* getpgrp() */
 149                 mutex_enter(&pidlock);
 150                 retval = p->p_pgrp;
 151                 mutex_exit(&pidlock);
 152                 break;
 153
 154         case 2: /* getsid() */
 155         case 4: /* getpgid() */
 156                 if (pid < 0 || pid >= maxpid) {
 157                         return (set_errno(EINVAL));
 158                 }
 159                 mutex_enter(&pidlock);
 160                 if (pid != 0 && p->p_pid != pid &&
 161                     ((p = prfind(pid)) == NULL || p->p_stat == SIDL)) {
 162                         mutex_exit(&pidlock);
 163                         return (set_errno(ESRCH));
 164                 }
 165                 if (flag == 2)
 166                         retval = p->p_sessp->s_sid;
 167                 else
 168                         retval = p->p_pgrp;
 169                 mutex_exit(&pidlock);
 170                 break;
 171
 172         }
 173         return (retval);
 174 }