/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1988, 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * This program is not related to David Wall, whose Stanford Ph.D. thesis
 * is entitled "Mechanisms for Broadcast and Selective Broadcast".
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/uio.h>

#include <ctype.h>
#include <err.h>
#include <grp.h>
#include <locale.h>
#include <paths.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utmpx.h>
#include <wchar.h>
#include <wctype.h>

#include "ttymsg.h"

static void makemsg(char *);
static void usage(void) __dead2;

static struct wallgroup {
        struct wallgroup *next;
        char            *name;
        gid_t           gid;
} *grouplist;
static int nobanner;
static int mbufsize;
static char *mbuf;

static int
ttystat(char *line)
{
        struct stat sb;
        char ttybuf[MAXPATHLEN];

        (void)snprintf(ttybuf, sizeof(ttybuf), "%s%s", _PATH_DEV, line);
        if (stat(ttybuf, &sb) == 0) {
                return (0);
        } else
                return (-1);
}

int
main(int argc, char *argv[])
{
        struct iovec iov;
        struct utmpx *utmp;
        int ch;
        int ingroup;
        struct wallgroup *g;
        struct group *grp;
        char **np;
        const char *p;
        struct passwd *pw;

        (void)setlocale(LC_CTYPE, "");

        while ((ch = getopt(argc, argv, "g:n")) != -1)
                switch (ch) {
                case 'n':
                        /* undoc option for shutdown: suppress banner */
                        if (geteuid() == 0)
                                nobanner = 1;
                        break;
                case 'g':
                        g = (struct wallgroup *)malloc(sizeof *g);
                        g->next = grouplist;
                        g->name = optarg;
                        g->gid = -1;
                        grouplist = g;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;
        if (argc > 1)
                usage();

        for (g = grouplist; g; g = g->next) {
                grp = getgrnam(g->name);
                if (grp != NULL)
                        g->gid = grp->gr_gid;
                else
                        warnx("%s: no such group", g->name);
        }

        makemsg(*argv);

        iov.iov_base = mbuf;
        iov.iov_len = mbufsize;
        /* NOSTRICT */
        while ((utmp = getutxent()) != NULL) {
                if (utmp->ut_type != USER_PROCESS)
                        continue;
                if (ttystat(utmp->ut_line) != 0)
                        continue;
                if (grouplist) {
                        ingroup = 0;
                        pw = getpwnam(utmp->ut_user);
                        if (!pw)
                                continue;
                        for (g = grouplist; g && ingroup == 0; g = g->next) {
                                if (g->gid == (gid_t)-1)
                                        continue;
                                if (g->gid == pw->pw_gid)
                                        ingroup = 1;
                                else if ((grp = getgrgid(g->gid)) != NULL) {
                                        for (np = grp->gr_mem; *np; np++) {
                                                if (strcmp(*np, utmp->ut_user) == 0) {
                                                        ingroup = 1;
                                                        break;
                                                }
                                        }
                                }
                        }
                        if (ingroup == 0)
                                continue;
                }
                if ((p = ttymsg(&iov, 1, utmp->ut_line, 60*5)) != NULL)
                        warnx("%s", p);
        }
        exit(0);
}

static void
usage(void)
{
        (void)fprintf(stderr, "usage: wall [-g group] [file]\n");
        exit(1);
}

void
makemsg(char *fname)
{
        int cnt;
        wchar_t ch;
        struct tm *lt;
        struct passwd *pw;
        struct stat sbuf;
        time_t now;
        FILE *fp;
        int fd;
        char hostname[MAXHOSTNAMELEN], tmpname[64];
        wchar_t *p, *tmp, lbuf[256], codebuf[13];
        const char *tty;
        const char *whom;
        gid_t egid;

        (void)snprintf(tmpname, sizeof(tmpname), "%s/wall.XXXXXX", _PATH_TMP);
        if ((fd = mkstemp(tmpname)) == -1 || !(fp = fdopen(fd, "r+")))
                err(1, "can't open temporary file");
        (void)unlink(tmpname);

        if (!nobanner) {
                tty = ttyname(STDERR_FILENO);
                if (tty == NULL)
                        tty = "no tty";

                if (!(whom = getlogin()))
                        whom = (pw = getpwuid(getuid())) ? pw->pw_name : "???";
                (void)gethostname(hostname, sizeof(hostname));
                (void)time(&now);
                lt = localtime(&now);

                /*
                 * all this stuff is to blank out a square for the message;
                 * we wrap message lines at column 79, not 80, because some
                 * terminals wrap after 79, some do not, and we can't tell.
                 * Which means that we may leave a non-blank character
                 * in column 80, but that can't be helped.
                 */
                (void)fwprintf(fp, L"\r%79s\r\n", " ");
                (void)swprintf(lbuf, sizeof(lbuf)/sizeof(wchar_t),
                    L"Broadcast Message from %s@%s",
                    whom, hostname);
                (void)fwprintf(fp, L"%-79.79S\007\007\r\n", lbuf);
                (void)swprintf(lbuf, sizeof(lbuf)/sizeof(wchar_t),
                    L"        (%s) at %d:%02d %s...", tty,
                    lt->tm_hour, lt->tm_min, lt->tm_zone);
                (void)fwprintf(fp, L"%-79.79S\r\n", lbuf);
        }
        (void)fwprintf(fp, L"%79s\r\n", " ");

        if (fname) {
                egid = getegid();
                setegid(getgid());
                if (freopen(fname, "r", stdin) == NULL)
                        err(1, "can't read %s", fname);
                if (setegid(egid) != 0)
                        err(1, "setegid failed");
        }
        cnt = 0;
        while (fgetws(lbuf, sizeof(lbuf)/sizeof(wchar_t), stdin)) {
                for (p = lbuf; (ch = *p) != L'\0'; ++p, ++cnt) {
                        if (ch == L'\r') {
                                putwc(L'\r', fp);
                                cnt = 0;
                                continue;
                        } else if (ch == L'\n') {
                                for (; cnt < 79; ++cnt)
                                        putwc(L' ', fp);
                                putwc(L'\r', fp);
                                putwc(L'\n', fp);
                                break;
                        }
                        if (cnt == 79) {
                                putwc(L'\r', fp);
                                putwc(L'\n', fp);
                                cnt = 0;
                        }
                        if (iswprint(ch) || iswspace(ch) || ch == L'\a' || ch == L'\b') {
                                putwc(ch, fp);
                        } else {
                                (void)swprintf(codebuf, sizeof(codebuf)/sizeof(wchar_t), L"<0x%X>", ch);
                                for (tmp = codebuf; *tmp != L'\0'; ++tmp) {
                                        putwc(*tmp, fp);
                                        if (++cnt == 79) {
                                                putwc(L'\r', fp);
                                                putwc(L'\n', fp);
                                                cnt = 0;
                                        }
                                }
                                --cnt;
                        }
                }
        }
        (void)fwprintf(fp, L"%79s\r\n", " ");
        rewind(fp);

        if (fstat(fd, &sbuf))
                err(1, "can't stat temporary file");
        mbufsize = sbuf.st_size;
        if (!(mbuf = malloc((u_int)mbufsize)))
                err(1, "out of memory");
        if ((int)fread(mbuf, sizeof(*mbuf), mbufsize, fp) != mbufsize)
                err(1, "can't read temporary file");
        fclose(fp);
}