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Annotation of 43BSDTahoe/bin/wall.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1980 Regents of the University of California.
                      3:  * All rights reserved.  The Berkeley software License Agreement
                      4:  * specifies the terms and conditions for redistribution.
                      5:  */
                      6: 
                      7: #ifndef lint
                      8: char copyright[] =
                      9: "@(#) Copyright (c) 1980 Regents of the University of California.\n\
                     10:  All rights reserved.\n";
                     11: #endif not lint
                     12: 
                     13: #ifndef lint
                     14: static char sccsid[] = "@(#)wall.c     5.4 (Berkeley) 10/22/87";
                     15: #endif not lint
                     16: 
                     17: /*
                     18:  * wall.c - Broadcast a message to all users.
                     19:  *
                     20:  * This program is not related to David Wall, whose Stanford Ph.D. thesis
                     21:  * is entitled "Mechanisms for Broadcast and Selective Broadcast".
                     22:  */
                     23: 
                     24: #include <stdio.h>
                     25: #include <utmp.h>
                     26: #include <errno.h>
                     27: #include <signal.h>
                     28: #include <sys/time.h>
                     29: #include <fcntl.h>
                     30: #include <sys/types.h>
                     31: #include <sys/stat.h>
                     32: 
                     33: #define IGNOREUSER     "sleeper"
                     34: 
                     35: char   hostname[32];
                     36: char   mesg[3000];
                     37: int    msize,sline;
                     38: struct utmp *utmp;
                     39: char   *strcpy();
                     40: char   *strcat();
                     41: char   *malloc();
                     42: char   who[9] = "???";
                     43: long   clock, time();
                     44: struct tm *localtime();
                     45: struct tm *localclock;
                     46: 
                     47: extern errno;
                     48: 
                     49: main(argc, argv)
                     50: char *argv[];
                     51: {
                     52:        register int i, c;
                     53:        register struct utmp *p;
                     54:        int f;
                     55:        struct stat statb;
                     56: 
                     57:        (void) gethostname(hostname, sizeof (hostname));
                     58:        if ((f = open("/etc/utmp", O_RDONLY, 0)) < 0) {
                     59:                fprintf(stderr, "Cannot open /etc/utmp\n");
                     60:                exit(1);
                     61:        }
                     62:        clock = time( 0 );
                     63:        localclock = localtime( &clock );
                     64:        sline = ttyslot();      /* 'utmp' slot no. of sender */
                     65:        (void) fstat(f, &statb);
                     66:        utmp = (struct utmp *)malloc(statb.st_size);
                     67:        c = read(f, (char *)utmp, statb.st_size);
                     68:        (void) close(f);
                     69:        c /= sizeof(struct utmp);
                     70:        if (sline)
                     71:                strncpy(who, utmp[sline].ut_name, sizeof(utmp[sline].ut_name));
                     72:        (void)sprintf(mesg,
                     73:            "\n\007\007Broadcast Message from %s@%s (%.*s) at %d:%02d ...\r\n\n"
                     74:                , who
                     75:                , hostname
                     76:                , sizeof(utmp[sline].ut_line)
                     77:                , utmp[sline].ut_line
                     78:                , localclock -> tm_hour
                     79:                , localclock -> tm_min
                     80:        );
                     81:        msize = strlen(mesg);
                     82:        if (argc >= 2) {
                     83:                /* take message from unix file instead of standard input */
                     84:                if (freopen(argv[1], "r", stdin) == NULL) {
                     85:                        perror(argv[1]);
                     86:                        exit(1);
                     87:                }
                     88:        }
                     89:        while ((i = getchar()) != EOF) {
                     90:                if (i == '\n')
                     91:                        mesg[msize++] = '\r';
                     92:                if (msize >= sizeof mesg) {
                     93:                        fprintf(stderr, "Message too long\n");
                     94:                        exit(1);
                     95:                }
                     96:                mesg[msize++] = i;
                     97:        }
                     98:        fclose(stdin);
                     99:        for (i=0; i<c; i++) {
                    100:                p = &utmp[i];
                    101:                if (p->ut_name[0] == 0 ||
                    102:                    strncmp(p->ut_name, IGNOREUSER, sizeof(p->ut_name)) == 0)
                    103:                        continue;
                    104:                sendmes(p->ut_line);
                    105:        }
                    106:        exit(0);
                    107: }
                    108: 
                    109: sendmes(tty)
                    110: char *tty;
                    111: {
                    112:        register f, flags;
                    113:        static char t[50] = "/dev/";
                    114:        int e, i;
                    115: 
                    116:        strcpy(t + 5, tty);
                    117: 
                    118:        if ((f = open(t, O_WRONLY|O_NDELAY)) < 0) {
                    119:                if (errno != EWOULDBLOCK)
                    120:                        perror(t);
                    121:                return;
                    122:        }
                    123:        if ((flags = fcntl(f, F_GETFL, 0)) == -1) {
                    124:                perror(t);
                    125:                return;
                    126:        }
                    127:        if (fcntl(f, F_SETFL, flags | FNDELAY) == -1)
                    128:                goto oldway;
                    129:        i = write(f, mesg, msize);
                    130:        e = errno;
                    131:        (void) fcntl(f, F_SETFL, flags);
                    132:        if (i == msize) {
                    133:                (void) close(f);
                    134:                return;
                    135:        }
                    136:        if (e != EWOULDBLOCK) {
                    137:                errno = e;
                    138:                perror(t);
                    139:                (void) close(f);
                    140:                return;
                    141:        }
                    142: oldway:
                    143:        while ((i = fork()) == -1)
                    144:                if (wait((int *)0) == -1) {
                    145:                        fprintf(stderr, "Try again\n");
                    146:                        return;
                    147:                }
                    148:        if (i) {
                    149:                (void) close(f);
                    150:                return;
                    151:        }
                    152: 
                    153:        (void) write(f, mesg, msize);
                    154:        exit(0);
                    155: }

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