cmd/wall/wall.c

	wall.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*  Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */


/*
 * Copyright 1988-2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <signal.h>
#include <stdio.h>
#include <grp.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <sys/stat.h>
#include <utmpx.h>
#include <sys/utsname.h>
#include <dirent.h>
#include <pwd.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include <locale.h>
#include <syslog.h>
#include <sys/wait.h>
#include <limits.h>

/*
 * utmpx defines wider fields for user and line.  For compatibility of output,
 * we are limiting these to the old maximums in utmp. Define UTMPX_NAMELEN
 * to use the full lengths.
 */
#ifndef UTMPX_NAMELEN
/* XXX - utmp -fix name length */
#define NMAX    (_POSIX_LOGIN_NAME_MAX - 1)
#define LMAX    12
#else /* UTMPX_NAMELEN */
#define NMAX    (sizeof (((struct utmpx *)0)->ut_user)
#define LMAX    (sizeof (((struct utmpx *)0)->ut_line)
#endif /* UTMPX_NAMELEN */

static char mesg[3000];
static char *infile;
static int  gflag;
static struct   group *pgrp;
static char *grpname;
static char line[MAXNAMLEN+1] = "???";
static char systm[MAXNAMLEN+1];
static time_t   tloc;
static struct   utsname utsn;
static char who[9]  = "???";
static char time_buf[50];
#define DATE_FMT    "%a %b %e %H:%M:%S"

static void sendmes(struct utmpx *);
static int chkgrp(char *);
static char *copy_str_till(char *, char *, char, int);

int
main(int argc, char *argv[])
{
    int i = 0;
    struct utmpx *p;
    FILE    *f;
    char    *ptr, *start;
    struct  passwd *pwd;
    char    *term_name;
    int c;
    int aflag = 0;
    int errflg = 0;

    (void) setlocale(LC_ALL, "");

    while ((c = getopt(argc, argv, "g:a")) != EOF)
        switch (c) {
        case 'a':
            aflag++;
            break;
        case 'g':
            if (gflag) {
                (void) fprintf(stderr,
                    "Only one group allowed\n");
                exit(1);
            }
            if ((pgrp = getgrnam(grpname = optarg)) == NULL) {
                (void) fprintf(stderr, "Unknown group %s\n",
                    grpname);
                exit(1);
            }
            gflag++;
            break;
        case '?':
            errflg++;
            break;
        }

    if (errflg) {
        (void) fprintf(stderr,
            "Usage: wall [-a] [-g group] [files...]\n");
        return (1);
    }

    if (optind < argc)
        infile = argv[optind];

    if (uname(&utsn) == -1) {
        (void) fprintf(stderr, "wall: uname() failed, %s\n",
            strerror(errno));
        exit(2);
    }
    (void) strcpy(systm, utsn.nodename);

    /*
     * Get the name of the terminal wall is running from.
     */

    if ((term_name = ttyname(fileno(stderr))) != NULL) {
        /*
         * skip the leading "/dev/" in term_name
         */
        (void) strncpy(line, &term_name[5], sizeof (line) - 1);
    }

    if (who[0] == '?') {
        if (pwd = getpwuid(getuid()))
            (void) strncpy(&who[0], pwd->pw_name, sizeof (who));
    }

    f = stdin;
    if (infile) {
        f = fopen(infile, "r");
        if (f == NULL) {
            (void) fprintf(stderr, "Cannot open %s\n", infile);
            exit(1);
        }
    }

    start = &mesg[0];
    ptr = start;
    while ((ptr - start) < 3000) {
        size_t n;

        if (fgets(ptr, &mesg[sizeof (mesg)] - ptr, f) == NULL)
            break;
        if ((n = strlen(ptr)) == 0)
            break;
        ptr += n;
    }
    (void) fclose(f);

    /*
     * If the request is from the rwall daemon then use the caller's
     * name and host.  We determine this if all of the following is true:
     *  1) First 5 characters are "From "
     *  2) Next non-white characters are of the form "name@host:"
     */
    if (strcmp(line, "???") == 0) {
        char rwho[MAXNAMLEN+1];
        char rsystm[MAXNAMLEN+1];
        char *cp;

        if (strncmp(mesg, "From ", 5) == 0) {
            cp = &mesg[5];
            cp = copy_str_till(rwho, cp, '@', MAXNAMLEN + 1);
            if (rwho[0] != '\0') {
                cp = copy_str_till(rsystm, ++cp, ':',
                    MAXNAMLEN + 1);
                if (rsystm[0] != '\0') {
                    (void) strcpy(systm, rsystm);
                    (void) strncpy(rwho, who, 9);
                    (void) strcpy(line, "rpc.rwalld");
                }
            }
        }
    }
    (void) time(&tloc);
    (void) strftime(time_buf, sizeof (time_buf),
                DATE_FMT, localtime(&tloc));

    setutxent();
    while ((p = getutxent()) != NULL) {
        if (p->ut_type != USER_PROCESS)
            continue;
        /*
         * if (-a option OR NOT pty window login), send the message
         */
        if (aflag || !nonuser(*p))
            sendmes(p);
    }
    endutxent();

    (void) alarm(60);
    do {
        i = (int)wait((int *)0);
    } while (i != -1 || errno != ECHILD);

    return (0);
}

/*
 * Copy src to destination upto but not including the delim.
 * Leave dst empty if delim not found or whitespace encountered.
 * Return pointer to next character (delim, whitespace, or '\0')
 */
static char *
copy_str_till(char *dst, char *src, char delim, int len)
{
    int i = 0;

    while (*src != '\0' && i < len) {
        if (isspace(*src)) {
            dst[0] = '\0';
            return (src);
        }
        if (*src == delim) {
            dst[i] = '\0';
            return (src);
        }
        dst[i++] = *src++;
    }
    dst[0] = '\0';
    return (src);
}

/*
 * Note to future maintainers: with the change of wall to use the
 * getutxent() API, the forked children (created by this function)
 * must call _exit as opposed to exit. This is necessary to avoid
 * unwanted fflushing of getutxent's stdio stream (caused by atexit
 * processing).
 */
static void
sendmes(struct utmpx *p)
{
    int i;
    char *s;
    static char device[LMAX + 6];
    char *bp;
    int ibp;
    FILE *f;
    int fd;

    if (gflag)
        if (!chkgrp(p->ut_user))
            return;
    while ((i = (int)fork()) == -1) {
        (void) alarm(60);
        (void) wait((int *)0);
        (void) alarm(0);
    }

    if (i)
        return;

    (void) signal(SIGHUP, SIG_IGN);
    (void) alarm(60);
    s = &device[0];
    (void) snprintf(s, sizeof (device), "/dev/%.*s", LMAX, p->ut_line);

    /* check if the device is really a tty */
    if ((fd = open(s, O_WRONLY|O_NOCTTY|O_NONBLOCK)) == -1) {
        (void) fprintf(stderr, "Cannot send to %.*s on %s\n",
            NMAX, p->ut_user, s);
        perror("open");
        (void) fflush(stderr);
        _exit(1);
    } else {
        if (!isatty(fd)) {
            (void) fprintf(stderr,
                "Cannot send to device %.*s %s\n",
                LMAX, p->ut_line,
                "because it's not a tty");
            openlog("wall", 0, LOG_AUTH);
            syslog(LOG_CRIT, "%.*s in utmpx is not a tty\n",
                LMAX, p->ut_line);
            closelog();
            (void) fflush(stderr);
            _exit(1);
        }
    }
#ifdef DEBUG
    (void) close(fd);
    f = fopen("wall.debug", "a");
#else
    f = fdopen(fd, "w");
#endif
    if (f == NULL) {
        (void) fprintf(stderr, "Cannot send to %-.*s on %s\n",
            NMAX, &p->ut_user[0], s);
        perror("open");
        (void) fflush(stderr);
        _exit(1);
    }
    (void) fprintf(f,
        "\07\07\07Broadcast Message from %s (%s) on %s %19.19s",
        who, line, systm, time_buf);
    if (gflag)
        (void) fprintf(f, " to group %s", grpname);
    (void) fprintf(f, "...\n");
#ifdef DEBUG
    (void) fprintf(f, "DEBUG: To %.8s on %s\n", p->ut_user, s);
#endif
    i = strlen(mesg);
    for (bp = mesg; --i >= 0; bp++) {
        ibp = (unsigned int)((unsigned char) *bp);
        if (*bp == '\n')
            (void) putc('\r', f);
        if (isprint(ibp) || *bp == '\r' || *bp == '\013' ||
            *bp == ' ' || *bp == '\t' || *bp == '\n' || *bp == '\007') {
            (void) putc(*bp, f);
        } else {
            if (!isascii(*bp)) {
                (void) fputs("M-", f);
                *bp = toascii(*bp);
            }
            if (iscntrl(*bp)) {
                (void) putc('^', f);
                (void) putc(*bp + 0100, f);
            }
            else
                (void) putc(*bp, f);
        }

        if (*bp == '\n')
            (void) fflush(f);

        if (ferror(f) || feof(f)) {
            (void) printf("\n\007Write failed\n");
            (void) fflush(stdout);
            _exit(1);
        }
    }
    (void) fclose(f);
    (void) close(fd);
    _exit(0);
}


static int
chkgrp(char *name)
{
    int i;
    char *p;

    for (i = 0; pgrp->gr_mem[i] && pgrp->gr_mem[i][0]; i++) {
        for (p = name; *p && *p != ' '; p++);
        *p = 0;
        if (strncmp(name, pgrp->gr_mem[i], 8) == 0)
            return (1);
    }

    return (0);
}