write.c revision 200160
11590Srgrimes/* 21590Srgrimes * Copyright (c) 1989, 1993 31590Srgrimes * The Regents of the University of California. All rights reserved. 41590Srgrimes * 51590Srgrimes * This code is derived from software contributed to Berkeley by 61590Srgrimes * Jef Poskanzer and Craig Leres of the Lawrence Berkeley Laboratory. 71590Srgrimes * 81590Srgrimes * Redistribution and use in source and binary forms, with or without 91590Srgrimes * modification, are permitted provided that the following conditions 101590Srgrimes * are met: 111590Srgrimes * 1. Redistributions of source code must retain the above copyright 121590Srgrimes * notice, this list of conditions and the following disclaimer. 131590Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141590Srgrimes * notice, this list of conditions and the following disclaimer in the 151590Srgrimes * documentation and/or other materials provided with the distribution. 161590Srgrimes * 3. All advertising materials mentioning features or use of this software 171590Srgrimes * must display the following acknowledgement: 181590Srgrimes * This product includes software developed by the University of 191590Srgrimes * California, Berkeley and its contributors. 201590Srgrimes * 4. Neither the name of the University nor the names of its contributors 211590Srgrimes * may be used to endorse or promote products derived from this software 221590Srgrimes * without specific prior written permission. 231590Srgrimes * 241590Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 251590Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 261590Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 271590Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 281590Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 291590Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 301590Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 311590Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 321590Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 331590Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 341590Srgrimes * SUCH DAMAGE. 351590Srgrimes */ 361590Srgrimes 371590Srgrimes#ifndef lint 3828794Scharnierstatic const char copyright[] = 391590Srgrimes"@(#) Copyright (c) 1989, 1993\n\ 401590Srgrimes The Regents of the University of California. All rights reserved.\n"; 4187682Smarkm#endif 421590Srgrimes 4391378Sdwmalone#if 0 441590Srgrimes#ifndef lint 4591378Sdwmalonestatic char sccsid[] = "@(#)write.c 8.1 (Berkeley) 6/6/93"; 4628794Scharnier#endif 4791378Sdwmalone#endif 481590Srgrimes 4991378Sdwmalone#include <sys/cdefs.h> 5091378Sdwmalone__FBSDID("$FreeBSD: head/usr.bin/write/write.c 200160 2009-12-05 20:22:26Z ed $"); 5191378Sdwmalone 521590Srgrimes#include <sys/param.h> 531590Srgrimes#include <sys/signal.h> 541590Srgrimes#include <sys/stat.h> 551590Srgrimes#include <sys/file.h> 561590Srgrimes#include <sys/time.h> 571590Srgrimes#include <ctype.h> 5828794Scharnier#include <err.h> 5929430Sache#include <locale.h> 6019190Salex#include <paths.h> 611590Srgrimes#include <pwd.h> 621590Srgrimes#include <stdio.h> 6391378Sdwmalone#include <stdlib.h> 641590Srgrimes#include <string.h> 65200160Sed#define _ULOG_POSIX_NAMES 66200160Sed#include <ulog.h> 6728794Scharnier#include <unistd.h> 681590Srgrimes 6992922Simpvoid done(int); 7092922Simpvoid do_write(char *, char *, uid_t); 7192922Simpstatic void usage(void); 7292922Simpint term_chk(char *, int *, time_t *, int); 7392922Simpvoid wr_fputs(unsigned char *s); 7492922Simpvoid search_utmp(char *, char *, char *, uid_t); 7592922Simpint utmp_chk(char *, char *); 761590Srgrimes 7728794Scharnierint 78102944Sdwmalonemain(int argc, char **argv) 791590Srgrimes{ 801590Srgrimes time_t atime; 811590Srgrimes uid_t myuid; 821590Srgrimes int msgsok, myttyfd; 8328794Scharnier char tty[MAXPATHLEN], *mytty; 841590Srgrimes 8529430Sache (void)setlocale(LC_CTYPE, ""); 8629430Sache 8797454Stjr while (getopt(argc, argv, "") != -1) 8897454Stjr usage(); 8997454Stjr argc -= optind; 9097454Stjr argv += optind; 9197454Stjr 921590Srgrimes /* check that sender has write enabled */ 931590Srgrimes if (isatty(fileno(stdin))) 941590Srgrimes myttyfd = fileno(stdin); 951590Srgrimes else if (isatty(fileno(stdout))) 961590Srgrimes myttyfd = fileno(stdout); 971590Srgrimes else if (isatty(fileno(stderr))) 981590Srgrimes myttyfd = fileno(stderr); 9928794Scharnier else 10028794Scharnier errx(1, "can't find your tty"); 10128794Scharnier if (!(mytty = ttyname(myttyfd))) 10228794Scharnier errx(1, "can't find your tty's name"); 103173572Sjhb if (!strncmp(mytty, _PATH_DEV, strlen(_PATH_DEV))) 104173572Sjhb mytty += strlen(_PATH_DEV); 1051590Srgrimes if (term_chk(mytty, &msgsok, &atime, 1)) 1061590Srgrimes exit(1); 10728794Scharnier if (!msgsok) 10828794Scharnier errx(1, "you have write permission turned off"); 1091590Srgrimes 1101590Srgrimes myuid = getuid(); 1111590Srgrimes 1121590Srgrimes /* check args */ 1131590Srgrimes switch (argc) { 11497454Stjr case 1: 11597454Stjr search_utmp(argv[0], tty, mytty, myuid); 1161590Srgrimes do_write(tty, mytty, myuid); 1171590Srgrimes break; 11897454Stjr case 2: 11997454Stjr if (!strncmp(argv[1], _PATH_DEV, strlen(_PATH_DEV))) 12097454Stjr argv[1] += strlen(_PATH_DEV); 12197454Stjr if (utmp_chk(argv[0], argv[1])) 12297454Stjr errx(1, "%s is not logged in on %s", argv[0], argv[1]); 12397454Stjr if (term_chk(argv[1], &msgsok, &atime, 1)) 1241590Srgrimes exit(1); 12528794Scharnier if (myuid && !msgsok) 12697454Stjr errx(1, "%s has messages disabled on %s", argv[0], argv[1]); 12797454Stjr do_write(argv[1], mytty, myuid); 1281590Srgrimes break; 1291590Srgrimes default: 13028794Scharnier usage(); 1311590Srgrimes } 13229430Sache done(0); 13328794Scharnier return (0); 1341590Srgrimes} 1351590Srgrimes 13628794Scharnierstatic void 137102944Sdwmaloneusage(void) 13828794Scharnier{ 13928794Scharnier (void)fprintf(stderr, "usage: write user [tty]\n"); 14028794Scharnier exit(1); 14128794Scharnier} 14228794Scharnier 1431590Srgrimes/* 1441590Srgrimes * utmp_chk - checks that the given user is actually logged in on 1451590Srgrimes * the given tty 1461590Srgrimes */ 14728794Scharnierint 148102944Sdwmaloneutmp_chk(char *user, char *tty) 1491590Srgrimes{ 150200160Sed struct utmpx lu, *u; 1511590Srgrimes 152200160Sed strncpy(lu.ut_line, tty, sizeof lu.ut_line); 153200160Sed setutxent(); 154200160Sed while ((u = getutxline(&lu)) != NULL) 155200160Sed if (u->ut_type == USER_PROCESS && 156200160Sed strcmp(user, u->ut_user) == 0) { 157200160Sed endutxent(); 1581590Srgrimes return(0); 1591590Srgrimes } 160200160Sed endutxent(); 1611590Srgrimes return(1); 1621590Srgrimes} 1631590Srgrimes 1641590Srgrimes/* 1651590Srgrimes * search_utmp - search utmp for the "best" terminal to write to 1661590Srgrimes * 1671590Srgrimes * Ignores terminals with messages disabled, and of the rest, returns 1681590Srgrimes * the one with the most recent access time. Returns as value the number 1691590Srgrimes * of the user's terminals with messages enabled, or -1 if the user is 1701590Srgrimes * not logged in at all. 1711590Srgrimes * 1721590Srgrimes * Special case for writing to yourself - ignore the terminal you're 1731590Srgrimes * writing from, unless that's the only terminal with messages enabled. 1741590Srgrimes */ 17528794Scharniervoid 176102944Sdwmalonesearch_utmp(char *user, char *tty, char *mytty, uid_t myuid) 1771590Srgrimes{ 178200160Sed struct utmpx *u; 1791590Srgrimes time_t bestatime, atime; 180200160Sed int nloggedttys, nttys, msgsok, user_is_me; 1811590Srgrimes 1821590Srgrimes nloggedttys = nttys = 0; 1831590Srgrimes bestatime = 0; 1841590Srgrimes user_is_me = 0; 185200160Sed 186200160Sed setutxent(); 187200160Sed while ((u = getutxent()) != NULL) 188200160Sed if (u->ut_type == USER_PROCESS && 189200160Sed strcmp(user, u->ut_user) == 0) { 1901590Srgrimes ++nloggedttys; 191200160Sed if (term_chk(u->ut_line, &msgsok, &atime, 0)) 1921590Srgrimes continue; /* bad term? skip */ 1931590Srgrimes if (myuid && !msgsok) 1941590Srgrimes continue; /* skip ttys with msgs off */ 195200160Sed if (strcmp(u->ut_line, mytty) == 0) { 1961590Srgrimes user_is_me = 1; 1971590Srgrimes continue; /* don't write to yourself */ 1981590Srgrimes } 1991590Srgrimes ++nttys; 2001590Srgrimes if (atime > bestatime) { 2011590Srgrimes bestatime = atime; 202200160Sed (void)strlcpy(tty, u->ut_line, MAXPATHLEN); 2031590Srgrimes } 2041590Srgrimes } 205200160Sed endutxent(); 2061590Srgrimes 20728794Scharnier if (nloggedttys == 0) 20828794Scharnier errx(1, "%s is not logged in", user); 2091590Srgrimes if (nttys == 0) { 2101590Srgrimes if (user_is_me) { /* ok, so write to yourself! */ 211200160Sed (void)strlcpy(tty, mytty, MAXPATHLEN); 2121590Srgrimes return; 2131590Srgrimes } 21428794Scharnier errx(1, "%s has messages disabled", user); 2151590Srgrimes } else if (nttys > 1) { 21628794Scharnier warnx("%s is logged in more than once; writing to %s", user, tty); 2171590Srgrimes } 2181590Srgrimes} 2191590Srgrimes 2201590Srgrimes/* 2211590Srgrimes * term_chk - check that a terminal exists, and get the message bit 2221590Srgrimes * and the access time 2231590Srgrimes */ 22428794Scharnierint 225102944Sdwmaloneterm_chk(char *tty, int *msgsokP, time_t *atimeP, int showerror) 2261590Srgrimes{ 2271590Srgrimes struct stat s; 2281590Srgrimes char path[MAXPATHLEN]; 2291590Srgrimes 23019190Salex (void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty); 2311590Srgrimes if (stat(path, &s) < 0) { 2321590Srgrimes if (showerror) 23328794Scharnier warn("%s", path); 2341590Srgrimes return(1); 2351590Srgrimes } 2361590Srgrimes *msgsokP = (s.st_mode & (S_IWRITE >> 3)) != 0; /* group write bit */ 2371590Srgrimes *atimeP = s.st_atime; 2381590Srgrimes return(0); 2391590Srgrimes} 2401590Srgrimes 2411590Srgrimes/* 2421590Srgrimes * do_write - actually make the connection 2431590Srgrimes */ 24428794Scharniervoid 245102944Sdwmalonedo_write(char *tty, char *mytty, uid_t myuid) 2461590Srgrimes{ 24787682Smarkm const char *login; 24887682Smarkm char *nows; 24987682Smarkm struct passwd *pwd; 25028794Scharnier time_t now; 25128794Scharnier char path[MAXPATHLEN], host[MAXHOSTNAMELEN], line[512]; 2521590Srgrimes 253139718Scognet /* Determine our login name before we reopen() stdout */ 25448566Sbillf if ((login = getlogin()) == NULL) { 25528794Scharnier if ((pwd = getpwuid(myuid))) 2561590Srgrimes login = pwd->pw_name; 2571590Srgrimes else 2581590Srgrimes login = "???"; 25948566Sbillf } 2601590Srgrimes 26119190Salex (void)snprintf(path, sizeof(path), "%s%s", _PATH_DEV, tty); 26228794Scharnier if ((freopen(path, "w", stdout)) == NULL) 26328794Scharnier err(1, "%s", path); 2641590Srgrimes 2651590Srgrimes (void)signal(SIGINT, done); 2661590Srgrimes (void)signal(SIGHUP, done); 2671590Srgrimes 2681590Srgrimes /* print greeting */ 2691590Srgrimes if (gethostname(host, sizeof(host)) < 0) 2701590Srgrimes (void)strcpy(host, "???"); 2711590Srgrimes now = time((time_t *)NULL); 2721590Srgrimes nows = ctime(&now); 2731590Srgrimes nows[16] = '\0'; 2741590Srgrimes (void)printf("\r\n\007\007\007Message from %s@%s on %s at %s ...\r\n", 2751590Srgrimes login, host, mytty, nows + 11); 2761590Srgrimes 2771590Srgrimes while (fgets(line, sizeof(line), stdin) != NULL) 2781590Srgrimes wr_fputs(line); 2791590Srgrimes} 2801590Srgrimes 2811590Srgrimes/* 2821590Srgrimes * done - cleanup and exit 2831590Srgrimes */ 2841590Srgrimesvoid 285102944Sdwmalonedone(int n __unused) 2861590Srgrimes{ 2871590Srgrimes (void)printf("EOF\r\n"); 2881590Srgrimes exit(0); 2891590Srgrimes} 2901590Srgrimes 2911590Srgrimes/* 2921590Srgrimes * wr_fputs - like fputs(), but makes control characters visible and 2931590Srgrimes * turns \n into \r\n 2941590Srgrimes */ 29528794Scharniervoid 296102944Sdwmalonewr_fputs(unsigned char *s) 2971590Srgrimes{ 2981590Srgrimes 29928794Scharnier#define PUTC(c) if (putchar(c) == EOF) err(1, NULL); 3001590Srgrimes 3011590Srgrimes for (; *s != '\0'; ++s) { 30211916Sache if (*s == '\n') { 3031590Srgrimes PUTC('\r'); 30429431Sache } else if (((*s & 0x80) && *s < 0xA0) || 30529431Sache /* disable upper controls */ 30629433Sache (!isprint(*s) && !isspace(*s) && 30729433Sache *s != '\a' && *s != '\b') 30829430Sache ) { 30912097Sache if (*s & 0x80) { 31012097Sache *s &= ~0x80; 31112097Sache PUTC('M'); 31212097Sache PUTC('-'); 31312097Sache } 31412097Sache if (iscntrl(*s)) { 31512097Sache *s ^= 0x40; 31612097Sache PUTC('^'); 31712097Sache } 31812097Sache } 31912097Sache PUTC(*s); 3201590Srgrimes } 3211590Srgrimes return; 3221590Srgrimes#undef PUTC 3231590Srgrimes} 324