usr/src/libexec/rbootd/rbootd.c

/*
 * Copyright (c) 1992 Regents of the University of California.
 * Copyright (c) 1988, 1992 The University of Utah and the Center
 *      for Software Science (CSS).
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Center for Software Science of the University of Utah Computer
 * Science Department.  CSS requests users of this software to return
 * to css-dist@cs.utah.edu any improvements that they make and grant
 * CSS redistribution rights.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)rbootd.c    5.2 (Berkeley) %G%
 *
 * Utah $Hdr: rbootd.c 3.1 92/07/06$
 * Author: Jeff Forys, University of Utah CSS
 */

#ifndef lint
static char sccsid[] = "@(#)rbootd.c    5.2 (Berkeley) %G%";
#endif /* not lint */

#include <sys/param.h>
#include <sys/ioctl.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "defs.h"


/* fd mask macros (backward compatibility with 4.2BSD) */
#ifndef FD_SET
#ifdef  notdef
typedef struct fd_set {         /* this should already be in 4.2 */
        int fds_bits[1];
} fd_set;
#endif
#define FD_ZERO(p)      ((p)->fds_bits[0] = 0)
#define FD_SET(n, p)    ((p)->fds_bits[0] |= (1 << (n)))
#define FD_CLR(n, p)    ((p)->fds_bits[0] &= ~(1 << (n)))
#define FD_ISSET(n, p)  ((p)->fds_bits[0] & (1 << (n)))
#endif

int
main(argc, argv)
        int argc;
        char *argv[];
{
        int c, fd, omask, maxfds;
        fd_set rset;

        /*
         *  Find what name we are running under.
         */
        ProgName = (ProgName = rindex(argv[0],'/')) ? ++ProgName : *argv;

        /*
         *  Close any open file descriptors.
         *  Temporarily leave stdin & stdout open for `-d',
         *  and stderr open for any pre-syslog error messages.
         */
        {
                int i, nfds = getdtablesize();

                for (i = 0; i < nfds; i++)
                        if (i != fileno(stdin) && i != fileno(stdout) &&
                            i != fileno(stderr))
                                (void) close(i);
        }

        /*
         *  Parse any arguments.
         */
        while ((c = getopt(argc, argv, "adi:")) != EOF)
                switch(c) {
                    case 'a':
                        BootAny++;
                        break;
                    case 'd':
                        DebugFlg++;
                        break;
                    case 'i':
                        IntfName = optarg;
                        break;
                }
        for (; optind < argc; optind++) {
                if (ConfigFile == NULL)
                        ConfigFile = argv[optind];
                else {
                        fprintf(stderr,
                                "%s: too many config files (`%s' ignored)\n",
                                ProgName, argv[optind]);
                }
        }

        if (ConfigFile == NULL)                 /* use default config file */
                ConfigFile = DfltConfig;

        if (DebugFlg) {
                DbgFp = stdout;                         /* output to stdout */

                (void) signal(SIGUSR1, SIG_IGN);        /* dont muck w/DbgFp */
                (void) signal(SIGUSR2, SIG_IGN);
        } else {
                (void) fclose(stdin);                   /* dont need these */
                (void) fclose(stdout);

                /*
                 *  Fork off a child to do the work & exit.
                 */
                switch(fork()) {
                        case -1:        /* fork failed */
                                fprintf(stderr, "%s: ", ProgName);
                                perror("fork");
                                Exit(0);
                        case 0:         /* this is the CHILD */
                                break;
                        default:        /* this is the PARENT */
                                _exit(0);
                }

                /*
                 *  Try to disassociate from the current tty.
                 */
                {
                        char *devtty = "/dev/tty";
                        int i;

                        if ((i = open(devtty, O_RDWR)) < 0) {
                                /* probably already disassociated */
                                if (setpgrp(0, 0) < 0) {
                                        fprintf(stderr, "%s: ", ProgName);
                                        perror("setpgrp");
                                }
                        } else {
                                if (ioctl(i, (u_long)TIOCNOTTY, (char *)0) < 0){
                                        fprintf(stderr, "%s: ", ProgName);
                                        perror("ioctl");
                                }
                                (void) close(i);
                        }
                }

                (void) signal(SIGUSR1, DebugOn);
                (void) signal(SIGUSR2, DebugOff);
        }

        (void) fclose(stderr);          /* finished with it */

#ifdef SYSLOG4_2
        openlog(ProgName, LOG_PID);
#else
        openlog(ProgName, LOG_PID, LOG_DAEMON);
#endif

        /*
         *  If no interface was specified, get one now.
         *
         *  This is convoluted because we want to get the default interface
         *  name for the syslog("restarted") message.  If BpfGetIntfName()
         *  runs into an error, it will return a syslog-able error message
         *  (in `errmsg') which will be displayed here.
         */
        if (IntfName == NULL) {
                char *errmsg;

                if ((IntfName = BpfGetIntfName(&errmsg)) == NULL) {
                        syslog(LOG_NOTICE, "restarted (??)");
                        syslog(LOG_ERR, errmsg);
                        Exit(0);
                }
        }

        syslog(LOG_NOTICE, "restarted (%s)", IntfName);

        (void) signal(SIGHUP, ReConfig);
        (void) signal(SIGINT, Exit);
        (void) signal(SIGTERM, Exit);

        /*
         *  Grab our host name and pid.
         */
        if (gethostname(MyHost, MAXHOSTNAMELEN) < 0) {
                syslog(LOG_ERR, "gethostname: %m");
                Exit(0);
        }
        MyHost[MAXHOSTNAMELEN] = '\0';

        MyPid = getpid();

        /*
         *  Write proc's pid to a file.
         */
        {
                FILE *fp;

                if ((fp = fopen(PidFile, "w")) != NULL) {
                        (void) fprintf(fp, "%d\n", MyPid);
                        (void) fclose(fp);
                } else {
                        syslog(LOG_WARNING, "fopen: failed (%s)", PidFile);
                }
        }

        /*
         *  All boot files are relative to the boot directory, we might
         *  as well chdir() there to make life easier.
         */
        if (chdir(BootDir) < 0) {
                syslog(LOG_ERR, "chdir: %m (%s)", BootDir);
                Exit(0);
        }

        /*
         *  Initial configuration.
         */
        omask = sigblock(sigmask(SIGHUP));      /* prevent reconfig's */
        if (GetBootFiles() == 0)                /* get list of boot files */
                Exit(0);
        if (ParseConfig() == 0)                 /* parse config file */
                Exit(0);

        /*
         *  Open and initialize a BPF device for the appropriate interface.
         *  If an error is encountered, a message is displayed and Exit()
         *  is called.
         */
        fd = BpfOpen();

        (void) sigsetmask(omask);               /* allow reconfig's */

        /*
         *  Main loop: receive a packet, determine where it came from,
         *  and if we service this host, call routine to handle request.
         */
        maxfds = fd + 1;
        FD_ZERO(&rset);
        FD_SET(fd, &rset);
        for (;;) {
                struct timeval timeout;
                fd_set r;
                int nsel;

                r = rset;

                if (RmpConns == NULL) {         /* timeout isnt necessary */
                        nsel = select(maxfds, &r, (fd_set *)0, (fd_set *)0,
                                      (struct timeval *)0);
                } else {
                        timeout.tv_sec = RMP_TIMEOUT;
                        timeout.tv_usec = 0;
                        nsel = select(maxfds, &r, (fd_set *)0, (fd_set *)0,
                                      &timeout);
                }

                if (nsel < 0) {
                        if (errno == EINTR)
                                continue;
                        syslog(LOG_ERR, "select: %m");
                        Exit(0);
                } else if (nsel == 0) {         /* timeout */
                        DoTimeout();                    /* clear stale conns */
                        continue;
                }

                if (FD_ISSET(fd, &r)) {
                        RMPCONN rconn;
                        CLIENT *client, *FindClient();
                        int doread = 1;

                        while (BpfRead(&rconn, doread)) {
                                doread = 0;

                                if (DbgFp != NULL)      /* display packet */
                                        DispPkt(&rconn,DIR_RCVD);

                                omask = sigblock(sigmask(SIGHUP));

                                /*
                                 *  If we do not restrict service, set the
                                 *  client to NULL (ProcessPacket() handles
                                 *  this).  Otherwise, check that we can
                                 *  service this host; if not, log a message
                                 *  and ignore the packet.
                                 */
                                if (BootAny) {
                                        client = NULL;
                                } else if ((client=FindClient(&rconn))==NULL) {
                                        syslog(LOG_INFO,
                                               "%s: boot packet ignored",
                                               EnetStr(&rconn));
                                        (void) sigsetmask(omask);
                                        continue;
                                }

                                ProcessPacket(&rconn,client);

                                (void) sigsetmask(omask);
                        }
                }
        }
}

/*
**  DoTimeout -- Free any connections that have timed out.
**
**      Parameters:
**              None.
**
**      Returns:
**              Nothing.
**
**      Side Effects:
**              - Timed out connections in `RmpConns' will be freed.
*/
void
DoTimeout()
{
        register RMPCONN *rtmp;
        struct timeval now;

        (void) gettimeofday(&now, (struct timezone *)0);

        /*
         *  For each active connection, if RMP_TIMEOUT seconds have passed
         *  since the last packet was sent, delete the connection.
         */
        for (rtmp = RmpConns; rtmp != NULL; rtmp = rtmp->next)
                if ((rtmp->tstamp.tv_sec + RMP_TIMEOUT) < now.tv_sec) {
                        syslog(LOG_WARNING, "%s: connection timed out (%u)",
                               EnetStr(rtmp), rtmp->rmp.r_type);
                        RemoveConn(rtmp);
                }
}

/*
**  FindClient -- Find client associated with a packet.
**
**      Parameters:
**              rconn - the new packet.
**
**      Returns:
**              Pointer to client info if found, NULL otherwise.
**
**      Side Effects:
**              None.
**
**      Warnings:
**              - This routine must be called with SIGHUP blocked since
**                a reconfigure can invalidate the information returned.
*/

CLIENT *
FindClient(rconn)
        register RMPCONN *rconn;
{
        register CLIENT *ctmp;

        for (ctmp = Clients; ctmp != NULL; ctmp = ctmp->next)
                if (bcmp((char *)&rconn->rmp.hp_hdr.saddr[0],
                         (char *)&ctmp->addr[0], RMP_ADDRLEN) == 0)
                        break;

        return(ctmp);
}

/*
**  Exit -- Log an error message and exit.
**
**      Parameters:
**              sig - caught signal (or zero if not dying on a signal).
**
**      Returns:
**              Does not return.
**
**      Side Effects:
**              - This process ceases to exist.
*/
void
Exit(sig)
        int sig;
{
        if (sig > 0)
                syslog(LOG_ERR, "going down on signal %d", sig);
        else
                syslog(LOG_ERR, "going down with fatal error");
        BpfClose();
        exit(1);
}

/*
**  ReConfig -- Get new list of boot files and reread config files.
**
**      Parameters:
**              None.
**
**      Returns:
**              Nothing.
**
**      Side Effects:
**              - All active connections are dropped.
**              - List of boot-able files is changed.
**              - List of clients is changed.
**
**      Warnings:
**              - This routine must be called with SIGHUP blocked.
*/
void
ReConfig(signo)
        int signo;
{
        syslog(LOG_NOTICE, "reconfiguring boot server");

        FreeConns();

        if (GetBootFiles() == 0)
                Exit(0);

        if (ParseConfig() == 0)
                Exit(0);
}

/*
**  DebugOff -- Turn off debugging.
**
**      Parameters:
**              None.
**
**      Returns:
**              Nothing.
**
**      Side Effects:
**              - Debug file is closed.
*/
void
DebugOff(signo)
        int signo;
{
        if (DbgFp != NULL)
                (void) fclose(DbgFp);

        DbgFp = NULL;
}

/*
**  DebugOn -- Turn on debugging.
**
**      Parameters:
**              None.
**
**      Returns:
**              Nothing.
**
**      Side Effects:
**              - Debug file is opened/truncated if not already opened,
**                otherwise do nothing.
*/
void
DebugOn(signo)
        int signo;
{
        if (DbgFp == NULL) {
                if ((DbgFp = fopen(DbgFile, "w")) == NULL)
                        syslog(LOG_ERR, "can't open debug file (%s)", DbgFile);
        }
}