usr/src/cmd/ttymon/tmsac.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, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  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"
  31
  32
  33 #include <stdlib.h>
  34 #include <stdio.h>
  35 #include <errno.h>
  36 #include <fcntl.h>
  37 #include <signal.h>
  38 #include <string.h>
  39 #include <unistd.h>
  40 #include "ttymon.h"
  41 #include "tmextern.h"
  42 #include "sac.h"
  43
  44 /*
  45  *      openpid - open the pid and put ttymon's pid in it
  46  *              - put an advisory lock on the file
  47  *              - to prevent another instance of ttymon in same directory
  48  *              - SAC also makes use of the lock
  49  *              - fd 0 is reserved for pid file
  50  */
  51 void
  52 openpid()
  53 {
  54         extern  int Lckfd;
  55         char lockbuf[16];       /* large enough for a PID string */
  56
  57         (void)close(0);
  58         /* open for read first, otherwise, may delete the pid already there*/
  59         if ((Lckfd = open(PIDFILE, O_RDONLY)) != -1) {
  60                 if (lockf(Lckfd, F_TEST, 0L) == -1)
  61                         fatal("pid file is locked. ttymon may already be "
  62                             "running!");
  63                 (void)close(Lckfd);
  64         }
  65
  66         if ((Lckfd = open(PIDFILE, O_WRONLY|O_CREAT|O_TRUNC, 0644 )) != 0)
  67                 fatal("open pid file failed: %s", strerror(errno));
  68
  69         if (lockf(Lckfd, F_LOCK, 0L) == -1)
  70                 fatal("lock pid file failed: %s", strerror(errno));
  71
  72         (void) snprintf(lockbuf, sizeof (lockbuf), "%ld", getpid());
  73         (void) write(Lckfd, lockbuf, strlen(lockbuf) + 1);
  74 #ifdef  DEBUG
  75         log("fd(pid)\t = %d", Lckfd);
  76 #endif
  77 }
  78
  79 /*
  80  * openpipes() -- open pmpipe and sacpipe to communicate with SAC
  81  *             -- Pfd, Sfd are global file descriptors for pmpipe, sacpipe
  82  */
  83
  84 void
  85 openpipes()
  86 {
  87         extern  int Pfd, Sfd;
  88
  89         Sfd = open(SACPIPE, O_WRONLY);
  90         if (Sfd < 0)
  91                 fatal("open sacpipe failed: %s", strerror(errno));
  92
  93         Pfd = open(PMPIPE, O_RDWR|O_NONBLOCK);
  94         if (Pfd < 0)
  95                 fatal("open pmpipe failed: %s", strerror(errno));
  96
  97 #ifdef  DEBUG
  98         log("fd(sacpipe)\t = %d",Sfd);
  99         log("fd(pmpipe)\t = %d",Pfd);
 100 #endif
 101 }
 102
 103 /*
 104  * remove_env(env) - remove an environment variable from the environment
 105  */
 106 static  void
 107 remove_env(env)
 108 char    *env;
 109 {
 110         extern  char    **environ;
 111         char    **p;
 112         char    **rp = NULL;
 113
 114         p = environ;
 115         if (p == NULL)
 116                 return;
 117         while (*p) {
 118                 if (strncmp(*p, env,strlen(env)) == 0)
 119                         rp = p;
 120                 p++;
 121         }
 122         if (rp) {
 123                 *rp = *--p;
 124                 *p = NULL;
 125         }
 126 }
 127
 128 /*
 129  * get_environ() -- get env variables PMTAG, ISTATE
 130  *               -- set global variables Tag, State
 131  */
 132
 133 void
 134 get_environ()
 135 {
 136         extern  char State, *Istate, *Tag;
 137
 138         if ((Tag = getenv("PMTAG")) == NULL)
 139                 fatal("PMTAG is missing");
 140
 141         if ((Istate = getenv("ISTATE")) == NULL)
 142                 fatal("ISTATE is missing");
 143
 144         State = (!strcmp(Istate, "enabled")) ? PM_ENABLED : PM_DISABLED;
 145
 146         /*
 147          * remove the environment variables so they will not
 148          * be passed to the children
 149          */
 150         remove_env("ISTATE");
 151         remove_env("PMTAG");
 152 }
 153
 154 /*
 155  * sacpoll      - the event handler when sac event is posted
 156  */
 157 void
 158 sacpoll()
 159 {
 160         int     ret;
 161         char    oldState;
 162         struct  sacmsg sacmsg;
 163         struct  pmmsg pmmsg;
 164         sigset_t        cset;
 165         sigset_t        tset;
 166
 167 #ifdef  DEBUG
 168         debug("in sacpoll");
 169 #endif
 170
 171         /* we don't want to be interrupted by sigchild now */
 172         (void)sigprocmask(SIG_SETMASK, NULL, &cset);
 173         tset = cset;
 174         (void)sigaddset(&tset, SIGCLD);
 175         (void)sigprocmask(SIG_SETMASK, &tset, NULL);
 176
 177         /*
 178          *      read sac messages, one at a time until no message
 179          *      is left on the pipe.
 180          *      the pipe is open with O_NONBLOCK, read will return -1
 181          *      and errno = EAGAIN if nothing is on the pipe
 182          */
 183         for (;;) {
 184
 185                 ret = read(Pfd, &sacmsg, sizeof(sacmsg));
 186                 if (ret < 0) {
 187                         switch(errno) {
 188                         case EAGAIN:
 189                                 /* no more data on the pipe */
 190                                 (void)sigprocmask(SIG_SETMASK, &cset, NULL);
 191                                 return;
 192                         case EINTR:
 193                                 break;
 194                         default:
 195                                 fatal("pmpipe read failed: %s",
 196                                     strerror(errno));
 197                                 break;  /*NOTREACHED*/
 198                         }
 199                 }
 200                 else if (ret == 0) {
 201                         /* no more data on the pipe */
 202                         (void)sigprocmask(SIG_SETMASK, &cset, NULL);
 203                         return;
 204                 }
 205                 else {
 206                         pmmsg.pm_size = 0;
 207                         (void) strcpy(pmmsg.pm_tag, Tag);
 208                         pmmsg.pm_maxclass = TM_MAXCLASS;
 209                         pmmsg.pm_type = PM_STATUS;
 210                         switch(sacmsg.sc_type) {
 211                         case SC_STATUS:
 212                                 break;
 213                         case SC_ENABLE:
 214                                 log("Got SC_ENABLE message");
 215                                 oldState = State;
 216                                 State = PM_ENABLED;
 217                                 if (State != oldState) {
 218 #ifdef  DEBUG
 219                                         debug("state changed to ENABLED");
 220 #endif
 221                                         state_change();
 222                                 }
 223                                 break;
 224                         case SC_DISABLE:
 225                                 log("Got SC_DISABLE message");
 226                                 oldState = State;
 227                                 State = PM_DISABLED;
 228                                 if (State != oldState) {
 229 #ifdef  DEBUG
 230                                         debug("state changed to DISABLED");
 231 #endif
 232                                         state_change();
 233                                 }
 234                                 break;
 235                         case SC_READDB:
 236                                 log("Got SC_READDB message");
 237                                 Reread_flag = 1;
 238                                 break;
 239                         default:
 240                                 log("Got unknown message %d", sacmsg.sc_type);
 241                                 pmmsg.pm_type = PM_UNKNOWN;
 242                                 break;
 243                         } /* end switch */
 244                         pmmsg.pm_state = State;
 245
 246                         while (write(Sfd, &pmmsg, sizeof(pmmsg)) != sizeof(pmmsg)) {
 247                                 if (errno == EINTR)
 248                                         continue;
 249                                 log("sanity response to SAC failed: %s",
 250                                     strerror(errno));
 251                                 break;
 252                         }
 253                 }
 254         } /* end for loop */
 255 }