usr/src/usr.sbin/rwhod/rwhod.c

#ifndef lint
static char sccsid[] = "@(#)rwhod.c     4.30 (Berkeley) 85/06/06";
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/file.h>

#include <net/if.h>
#include <netinet/in.h>

#include <nlist.h>
#include <stdio.h>
#include <signal.h>
#include <errno.h>
#include <utmp.h>
#include <ctype.h>
#include <netdb.h>
#include <syslog.h>
#include "rwhod.h"

/*
 * Alarm interval. Don't forget to change the down time check in ruptime
 * if this is changed.
 */
#define AL_INTERVAL (3 * 60)

struct  sockaddr_in sin = { AF_INET };

extern  errno;

char    myname[32];

struct  nlist nl[] = {
#define NL_AVENRUN      0
        { "_avenrun" },
#define NL_BOOTTIME     1
        { "_boottime" },
        0
};

/*
 * We communicate with each neighbor in
 * a list constructed at the time we're
 * started up.  Neighbors are currently
 * directly connected via a hardware interface.
 */
struct  neighbor {
        struct  neighbor *n_next;
        char    *n_name;                /* interface name */
        char    *n_addr;                /* who to send to */
        int     n_addrlen;              /* size of address */
        int     n_flags;                /* should forward?, interface flags */
};

struct  neighbor *neighbors;
struct  whod mywd;
struct  servent *sp;
int     s, utmpf, kmemf = -1;

#define WHDRSIZE        (sizeof (mywd) - sizeof (mywd.wd_we))
#define RWHODIR         "/usr/spool/rwho"

int     onalrm();
char    *strcpy(), *sprintf(), *malloc();
long    lseek();
int     getkmem();
struct  in_addr inet_makeaddr();

main()
{
        struct sockaddr_in from;
        char path[64];
        int addr, on = 1;
        struct hostent *hp;

        if (getuid()) {
                fprintf(stderr, "rwhod: not super user\n");
                exit(1);
        }
        sp = getservbyname("who", "udp");
        if (sp == 0) {
                fprintf(stderr, "rwhod: udp/who: unknown service\n");
                exit(1);
        }
#ifndef DEBUG
        if (fork())
                exit(0);
        { int s;
          for (s = 0; s < 10; s++)
                (void) close(s);
          (void) open("/", 0);
          (void) dup2(0, 1);
          (void) dup2(0, 2);
          s = open("/dev/tty", 2);
          if (s >= 0) {
                ioctl(s, TIOCNOTTY, 0);
                (void) close(s);
          }
        }
#endif
        (void) chdir("/dev");
        (void) signal(SIGHUP, getkmem);
        openlog("rwhod", LOG_PID, 0);
        /*
         * Establish host name as returned by system.
         */
        if (gethostname(myname, sizeof (myname) - 1) < 0) {
                syslog(LOG_ERR, "gethostname: %m");
                exit(1);
        }
        strncpy(mywd.wd_hostname, myname, sizeof (myname) - 1);
        utmpf = open("/etc/utmp", O_RDONLY);
        if (utmpf < 0) {
                (void) close(creat("/etc/utmp", 0644));
                utmpf = open("/etc/utmp", O_RDONLY);
        }
        if (utmpf < 0) {
                syslog(LOG_ERR, "/etc/utmp: %m");
                exit(1);
        }
        getkmem();
        if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
                syslog(LOG_ERR, "socket: %m");
                exit(1);
        }
        if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &on, sizeof (on)) < 0) {
                syslog(LOG_ERR, "setsockopt SO_BROADCAST: %m");
                exit(1);
        }
        hp = gethostbyname(myname);
        if (hp == NULL) {
                syslog(LOG_ERR, "%s: don't know my own name", myname);
                exit(1);
        }
        sin.sin_family = hp->h_addrtype;
        sin.sin_port = sp->s_port;
        if (bind(s, &sin, sizeof (sin)) < 0) {
                syslog(LOG_ERR, "bind: %m");
                exit(1);
        }
        if (!configure(s))
                exit(1);
        signal(SIGALRM, onalrm);
        onalrm();
        for (;;) {
                struct whod wd;
                int cc, whod, len = sizeof (from);

                cc = recvfrom(s, (char *)&wd, sizeof (struct whod), 0,
                        &from, &len);
                if (cc <= 0) {
                        if (cc < 0 && errno != EINTR)
                                syslog(LOG_WARNING, "recv: %m");
                        continue;
                }
                if (from.sin_port != sp->s_port) {
                        syslog(LOG_WARNING, "%d: bad from port",
                                ntohs(from.sin_port));
                        continue;
                }
#ifdef notdef
                if (gethostbyname(wd.wd_hostname) == 0) {
                        syslog(LOG_WARNING, "%s: unknown host",
                                wd.wd_hostname);
                        continue;
                }
#endif
                if (wd.wd_vers != WHODVERSION)
                        continue;
                if (wd.wd_type != WHODTYPE_STATUS)
                        continue;
                if (!verify(wd.wd_hostname)) {
                        syslog(LOG_WARNING, "malformed host name from %x",
                                from.sin_addr);
                        continue;
                }
                (void) sprintf(path, "%s/whod.%s", RWHODIR, wd.wd_hostname);
                whod = creat(path, 0666);
                if (whod < 0) {
                        syslog(LOG_WARNING, "%s: %m", path);
                        continue;
                }
#if vax || pdp11
                {
                        int i, n = (cc - WHDRSIZE)/sizeof(struct whoent);
                        struct whoent *we;

                        /* undo header byte swapping before writing to file */
                        wd.wd_sendtime = ntohl(wd.wd_sendtime);
                        for (i = 0; i < 3; i++)
                                wd.wd_loadav[i] = ntohl(wd.wd_loadav[i]);
                        wd.wd_boottime = ntohl(wd.wd_boottime);
                        we = wd.wd_we;
                        for (i = 0; i < n; i++) {
                                we->we_idle = ntohl(we->we_idle);
                                we->we_utmp.out_time =
                                    ntohl(we->we_utmp.out_time);
                                we++;
                        }
                }
#endif
                (void) time(&wd.wd_recvtime);
                (void) write(whod, (char *)&wd, cc);
                (void) close(whod);
        }
}

/*
 * Check out host name for unprintables
 * and other funnies before allowing a file
 * to be created.  Sorry, but blanks aren't allowed.
 */
verify(name)
        register char *name;
{
        register int size = 0;

        while (*name) {
                if (!isascii(*name) || !(isalnum(*name) || ispunct(*name)))
                        return (0);
                name++, size++;
        }
        return (size > 0);
}

int     utmptime;
int     utmpent;
int     utmpsize = 0;
struct  utmp *utmp;
int     alarmcount;

onalrm()
{
        register int i;
        struct stat stb;
        register struct whoent *we = mywd.wd_we, *wlast;
        int cc;
        double avenrun[3];
        time_t now = time(0);
        register struct neighbor *np;

        if (alarmcount % 10 == 0)
                getkmem();
        alarmcount++;
        (void) fstat(utmpf, &stb);
        if ((stb.st_mtime != utmptime) || (stb.st_size > utmpsize)) {
                utmptime = stb.st_mtime;
                if (stb.st_size > utmpsize) {
                        utmpsize = stb.st_size + 10 * sizeof(struct utmp);
                        if (utmp)
                                utmp = (struct utmp *)realloc(utmp, utmpsize);
                        else
                                utmp = (struct utmp *)malloc(utmpsize);
                        if (! utmp) {
                                fprintf(stderr, "rwhod: malloc failed\n");
                                utmpsize = 0;
                                goto done;
                        }
                }
                (void) lseek(utmpf, (long)0, L_SET);
                cc = read(utmpf, (char *)utmp, stb.st_size);
                if (cc < 0) {
                        perror("/etc/utmp");
                        goto done;
                }
                wlast = &mywd.wd_we[1024 / sizeof (struct whoent) - 1];
                utmpent = cc / sizeof (struct utmp);
                for (i = 0; i < utmpent; i++)
                        if (utmp[i].ut_name[0]) {
                                bcopy(utmp[i].ut_line, we->we_utmp.out_line,
                                   sizeof (utmp[i].ut_line));
                                bcopy(utmp[i].ut_name, we->we_utmp.out_name,
                                   sizeof (utmp[i].ut_name));
                                we->we_utmp.out_time = htonl(utmp[i].ut_time);
                                if (we >= wlast)
                                        break;
                                we++;
                        }
                utmpent = we - mywd.wd_we;
        }
        we = mywd.wd_we;
        for (i = 0; i < utmpent; i++) {
                if (stat(we->we_utmp.out_line, &stb) >= 0)
                        we->we_idle = htonl(now - stb.st_atime);
                we++;
        }
        (void) lseek(kmemf, (long)nl[NL_AVENRUN].n_value, L_SET);
        (void) read(kmemf, (char *)avenrun, sizeof (avenrun));
        for (i = 0; i < 3; i++)
                mywd.wd_loadav[i] = htonl((u_long)(avenrun[i] * 100));
        cc = (char *)we - (char *)&mywd;
        mywd.wd_sendtime = htonl(time(0));
        mywd.wd_vers = WHODVERSION;
        mywd.wd_type = WHODTYPE_STATUS;
        for (np = neighbors; np != NULL; np = np->n_next)
                (void) sendto(s, (char *)&mywd, cc, 0,
                        np->n_addr, np->n_addrlen);
done:
        (void) alarm(AL_INTERVAL);
}

getkmem()
{
        struct nlist *nlp;
        static ino_t vmunixino;
        static time_t vmunixctime;
        struct stat sb;

        if (stat("/vmunix", &sb) < 0) {
                if (vmunixctime)
                        return;
        } else {
                if (sb.st_ctime == vmunixctime && sb.st_ino == vmunixino)
                        return;
                vmunixctime = sb.st_ctime;
                vmunixino= sb.st_ino;
        }
        if (kmemf >= 0)
                (void) close(kmemf);
loop:
        if (nlist("/vmunix", nl)) {
                syslog(LOG_WARNING, "/vmunix namelist botch");
                sleep(300);
                goto loop;
        }
        kmemf = open("/dev/kmem", O_RDONLY);
        if (kmemf < 0) {
                syslog(LOG_ERR, "/dev/kmem: %m");
                exit(1);
        }
        (void) lseek(kmemf, (long)nl[NL_BOOTTIME].n_value, L_SET);
        (void) read(kmemf, (char *)&mywd.wd_boottime,
            sizeof (mywd.wd_boottime));
        mywd.wd_boottime = htonl(mywd.wd_boottime);
}

/*
 * Figure out device configuration and select
 * networks which deserve status information.
 */
configure(s)
        int s;
{
        char buf[BUFSIZ];
        struct ifconf ifc;
        struct ifreq ifreq, *ifr;
        struct sockaddr_in *sin;
        register struct neighbor *np;
        int n;

        ifc.ifc_len = sizeof (buf);
        ifc.ifc_buf = buf;
        if (ioctl(s, SIOCGIFCONF, (char *)&ifc) < 0) {
                syslog(LOG_ERR, "ioctl (get interface configuration)");
                return (0);
        }
        ifr = ifc.ifc_req;
        for (n = ifc.ifc_len / sizeof (struct ifreq); n > 0; n--, ifr++) {
                for (np = neighbors; np != NULL; np = np->n_next)
                        if (np->n_name &&
                            strcmp(ifr->ifr_name, np->n_name) == 0)
                                break;
                if (np != NULL)
                        continue;
                ifreq = *ifr;
                np = (struct neighbor *)malloc(sizeof (*np));
                if (np == NULL)
                        continue;
                np->n_name = malloc(strlen(ifr->ifr_name) + 1);
                if (np->n_name == NULL) {
                        free((char *)np);
                        continue;
                }
                strcpy(np->n_name, ifr->ifr_name);
                np->n_addrlen = sizeof (ifr->ifr_addr);
                np->n_addr = malloc(np->n_addrlen);
                if (np->n_addr == NULL) {
                        free(np->n_name);
                        free((char *)np);
                        continue;
                }
                bcopy((char *)&ifr->ifr_addr, np->n_addr, np->n_addrlen);
                if (ioctl(s, SIOCGIFFLAGS, (char *)&ifreq) < 0) {
                        syslog(LOG_ERR, "ioctl (get interface flags)");
                        free((char *)np);
                        continue;
                }
                if ((ifreq.ifr_flags & IFF_UP) == 0 ||
                    (ifreq.ifr_flags & (IFF_BROADCAST|IFF_POINTOPOINT)) == 0) {
                        free((char *)np);
                        continue;
                }
                np->n_flags = ifreq.ifr_flags;
                if (np->n_flags & IFF_POINTOPOINT) {
                        if (ioctl(s, SIOCGIFDSTADDR, (char *)&ifreq) < 0) {
                                syslog(LOG_ERR, "ioctl (get dstaddr)");
                                free((char *)np);
                                continue;
                        }
                        /* we assume addresses are all the same size */
                        bcopy((char *)&ifreq.ifr_dstaddr,
                          np->n_addr, np->n_addrlen);
                }
                if (np->n_flags & IFF_BROADCAST) {
                        if (ioctl(s, SIOCGIFBRDADDR, (char *)&ifreq) < 0) {
                                syslog(LOG_ERR, "ioctl (get broadaddr)");
                                free((char *)np);
                                continue;
                        }
                        /* we assume addresses are all the same size */
                        bcopy((char *)&ifreq.ifr_broadaddr,
                          np->n_addr, np->n_addrlen);
                }
                /* gag, wish we could get rid of Internet dependencies */
                sin = (struct sockaddr_in *)np->n_addr;
                sin->sin_port = sp->s_port;
                np->n_next = neighbors;
                neighbors = np;
        }
        return (1);
}

/*
 * Return the possible subnetwork number from an internet address.
 * If the address is of the form of a subnet address (most significant
 * bit of the host part is set), believe the subnet exists.
 * Otherwise, return the network number.  Any subnet number is only valid
 * if this is a ``local'' net.
 */
inet_subnetof(in)
        struct in_addr in;
{
        register u_long i = ntohl(in.s_addr);

        if (IN_CLASSA(i)) {
                if (IN_SUBNETA(i))
                        return ((i & IN_CLASSA_SUBNET) >> IN_CLASSA_SUBNSHIFT);
                else
                        return ((i & IN_CLASSA_NET) >> IN_CLASSA_NSHIFT);
        } else if (IN_CLASSB(i)) {
                if (IN_SUBNETB(i))
                        return ((i & IN_CLASSB_SUBNET) >> IN_CLASSB_SUBNSHIFT);
                else
                        return ((i & IN_CLASSB_NET) >> IN_CLASSB_NSHIFT);
        } else
                return ((i & IN_CLASSC_NET) >> IN_CLASSC_NSHIFT);
}

#ifdef DEBUG
sendto(s, buf, cc, flags, to, tolen)
        int s;
        char *buf;
        int cc, flags;
        char *to;
        int tolen;
{
        register struct whod *w = (struct whod *)buf;
        register struct whoent *we;
        struct sockaddr_in *sin = (struct sockaddr_in *)to;
        char *interval();

        printf("sendto %x.%d\n", ntohl(sin->sin_addr), ntohs(sin->sin_port));
        printf("hostname %s %s\n", w->wd_hostname,
           interval(ntohl(w->wd_sendtime) - ntohl(w->wd_boottime), "  up"));
        printf("load %4.2f, %4.2f, %4.2f\n",
            ntohl(w->wd_loadav[0]) / 100.0, ntohl(w->wd_loadav[1]) / 100.0,
            ntohl(w->wd_loadav[2]) / 100.0);
        cc -= WHDRSIZE;
        for (we = w->wd_we, cc /= sizeof (struct whoent); cc > 0; cc--, we++) {
                time_t t = ntohl(we->we_utmp.out_time);
                printf("%-8.8s %s:%s %.12s",
                        we->we_utmp.out_name,
                        w->wd_hostname, we->we_utmp.out_line,
                        ctime(&t)+4);
                we->we_idle = ntohl(we->we_idle) / 60;
                if (we->we_idle) {
                        if (we->we_idle >= 100*60)
                                we->we_idle = 100*60 - 1;
                        if (we->we_idle >= 60)
                                printf(" %2d", we->we_idle / 60);
                        else
                                printf("   ");
                        printf(":%02d", we->we_idle % 60);
                }
                printf("\n");
        }
}

char *
interval(time, updown)
        int time;
        char *updown;
{
        static char resbuf[32];
        int days, hours, minutes;

        if (time < 0 || time > 3*30*24*60*60) {
                (void) sprintf(resbuf, "   %s ??:??", updown);
                return (resbuf);
        }
        minutes = (time + 59) / 60;             /* round to minutes */
        hours = minutes / 60; minutes %= 60;
        days = hours / 24; hours %= 24;
        if (days)
                (void) sprintf(resbuf, "%s %2d+%02d:%02d",
                    updown, days, hours, minutes);
        else
                (void) sprintf(resbuf, "%s    %2d:%02d",
                    updown, hours, minutes);
        return (resbuf);
}
#endif