389 lines
9.8 KiB
C
389 lines
9.8 KiB
C
/*
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Jef Poskanzer and Craig Leres of the Lawrence Berkeley Laboratory.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* Modified for Linux, Mon Mar 8 18:16:24 1993, faith@cs.unc.edu
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* Wed Jun 22 21:41:56 1994, faith@cs.unc.edu:
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* Added fix from Mike Grupenhoff (kashmir@umiacs.umd.edu)
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* Mon Jul 1 17:01:39 MET DST 1996, janl@math.uio.no:
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* - Added fix from David.Chapell@mail.trincoll.edu enabeling daemons
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* to use write.
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* - ANSIed it since I was working on it anyway.
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* 1999-02-22 Arkadiusz Miśkiewicz <misiek@pld.ORG.PL>
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* - added Native Language Support
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*
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <utmp.h>
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#include <errno.h>
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#include <time.h>
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#include <pwd.h>
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#include <string.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <sys/param.h>
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#include <sys/stat.h>
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#include <paths.h>
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#include <getopt.h>
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#include "c.h"
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#include "carefulputc.h"
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#include "closestream.h"
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#include "nls.h"
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#include "xalloc.h"
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static void __attribute__ ((__noreturn__)) usage(FILE * out);
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void search_utmp(char *, char *, char *, uid_t);
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void do_write(char *, char *, uid_t);
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void wr_fputs(char *);
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static void __attribute__ ((__noreturn__)) done(int);
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int term_chk(char *, int *, time_t *, int);
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int utmp_chk(char *, char *);
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static gid_t root_access;
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static void __attribute__ ((__noreturn__)) usage(FILE * out)
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{
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fputs(USAGE_HEADER, out);
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fprintf(out,
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_(" %s [options] <user> [<ttyname>]\n"),
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program_invocation_short_name);
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fputs(USAGE_SEPARATOR, out);
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fputs(_("Send a message to another user.\n"), out);
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fputs(USAGE_OPTIONS, out);
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fputs(USAGE_HELP, out);
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fputs(USAGE_VERSION, out);
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fprintf(out, USAGE_MAN_TAIL("write(1)"));
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exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
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}
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int main(int argc, char **argv)
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{
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time_t atime;
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uid_t myuid;
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int msgsok, myttyfd, c;
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char tty[PATH_MAX], *mytty;
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static const struct option longopts[] = {
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{"version", no_argument, NULL, 'V'},
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{"help", no_argument, NULL, 'h'},
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{NULL, 0, NULL, 0}
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};
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setlocale(LC_ALL, "");
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bindtextdomain(PACKAGE, LOCALEDIR);
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textdomain(PACKAGE);
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atexit(close_stdout);
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while ((c = getopt_long(argc, argv, "Vh", longopts, NULL)) != -1)
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switch (c) {
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case 'V':
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printf(UTIL_LINUX_VERSION);
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return EXIT_SUCCESS;
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case 'h':
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usage(stdout);
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default:
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usage(stderr);
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}
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root_access = !getegid();
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/* check that sender has write enabled */
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if (isatty(fileno(stdin)))
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myttyfd = fileno(stdin);
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else if (isatty(fileno(stdout)))
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myttyfd = fileno(stdout);
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else if (isatty(fileno(stderr)))
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myttyfd = fileno(stderr);
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else
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myttyfd = -1;
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if (myttyfd != -1) {
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if (!(mytty = ttyname(myttyfd)))
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errx(EXIT_FAILURE,
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_("can't find your tty's name"));
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/*
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* We may have /dev/ttyN but also /dev/pts/xx. Below,
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* term_chk() will put "/dev/" in front, so remove that
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* part.
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*/
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if (!strncmp(mytty, "/dev/", 5))
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mytty += 5;
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if (term_chk(mytty, &msgsok, &atime, 1))
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exit(EXIT_FAILURE);
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if (!msgsok)
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errx(EXIT_FAILURE,
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_("you have write permission turned off"));
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} else
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mytty = "<no tty>";
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myuid = getuid();
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/* check args */
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switch (argc) {
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case 2:
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search_utmp(argv[1], tty, mytty, myuid);
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do_write(tty, mytty, myuid);
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break;
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case 3:
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if (!strncmp(argv[2], "/dev/", 5))
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argv[2] += 5;
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if (utmp_chk(argv[1], argv[2]))
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errx(EXIT_FAILURE,
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_("%s is not logged in on %s"),
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argv[1], argv[2]);
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if (term_chk(argv[2], &msgsok, &atime, 1))
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exit(EXIT_FAILURE);
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if (myuid && !msgsok)
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errx(EXIT_FAILURE,
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_("%s has messages disabled on %s"),
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argv[1], argv[2]);
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do_write(argv[2], mytty, myuid);
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break;
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default:
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usage(stderr);
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}
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done(0);
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/* NOTREACHED */
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return EXIT_FAILURE;
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}
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/*
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* utmp_chk - checks that the given user is actually logged in on
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* the given tty
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*/
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int utmp_chk(char *user, char *tty)
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{
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struct utmp u;
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struct utmp *uptr;
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int res = 1;
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utmpname(_PATH_UTMP);
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setutent();
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while ((uptr = getutent())) {
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memcpy(&u, uptr, sizeof(u));
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if (strncmp(user, u.ut_user, sizeof(u.ut_user)) == 0 &&
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strncmp(tty, u.ut_line, sizeof(u.ut_line)) == 0) {
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res = 0;
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break;
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}
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}
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endutent();
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return res;
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}
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/*
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* search_utmp - search utmp for the "best" terminal to write to
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*
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* Ignores terminals with messages disabled, and of the rest, returns
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* the one with the most recent access time. Returns as value the number
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* of the user's terminals with messages enabled, or -1 if the user is
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* not logged in at all.
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*
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* Special case for writing to yourself - ignore the terminal you're
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* writing from, unless that's the only terminal with messages enabled.
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*/
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void search_utmp(char *user, char *tty, char *mytty, uid_t myuid)
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{
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struct utmp u;
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struct utmp *uptr;
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time_t bestatime, atime;
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int nloggedttys, nttys, msgsok, user_is_me;
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char atty[sizeof(u.ut_line) + 1];
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utmpname(_PATH_UTMP);
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setutent();
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nloggedttys = nttys = 0;
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bestatime = 0;
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user_is_me = 0;
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while ((uptr = getutent())) {
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memcpy(&u, uptr, sizeof(u));
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if (strncmp(user, u.ut_user, sizeof(u.ut_user)) == 0) {
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++nloggedttys;
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strncpy(atty, u.ut_line, sizeof(u.ut_line));
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atty[sizeof(u.ut_line)] = '\0';
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if (term_chk(atty, &msgsok, &atime, 0))
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/* bad term? skip */
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continue;
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if (myuid && !msgsok)
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/* skip ttys with msgs off */
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continue;
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if (strcmp(atty, mytty) == 0) {
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user_is_me = 1;
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/* don't write to yourself */
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continue;
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}
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if (u.ut_type != USER_PROCESS)
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/* it's not a valid entry */
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continue;
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++nttys;
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if (atime > bestatime) {
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bestatime = atime;
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strcpy(tty, atty);
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}
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}
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}
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endutent();
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if (nloggedttys == 0)
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errx(EXIT_FAILURE, _("%s is not logged in"), user);
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if (nttys == 0) {
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if (user_is_me) {
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/* ok, so write to yourself! */
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strcpy(tty, mytty);
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return;
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}
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errx(EXIT_FAILURE, _("%s has messages disabled"), user);
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} else if (nttys > 1) {
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warnx(_("%s is logged in more than once; writing to %s"),
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user, tty);
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}
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}
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/*
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* term_chk - check that a terminal exists, and get the message bit
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* and the access time
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*/
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int term_chk(char *tty, int *msgsokP, time_t * atimeP, int showerror)
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{
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struct stat s;
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char path[PATH_MAX];
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if (strlen(tty) + 6 > sizeof(path))
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return 1;
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sprintf(path, "/dev/%s", tty);
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if (stat(path, &s) < 0) {
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if (showerror)
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warn("%s", path);
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return 1;
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}
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*msgsokP = !access(path, W_OK);
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if (!root_access && *msgsokP)
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*msgsokP = s.st_mode & S_IWGRP;
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*atimeP = s.st_atime;
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return 0;
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}
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/*
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* do_write - actually make the connection
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*/
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void do_write(char *tty, char *mytty, uid_t myuid)
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{
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char *login, *pwuid, *nows;
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struct passwd *pwd;
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time_t now;
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char path[PATH_MAX], *host, line[512];
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/* Determine our login name(s) before the we reopen() stdout */
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if ((pwd = getpwuid(myuid)) != NULL)
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pwuid = pwd->pw_name;
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else
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pwuid = "???";
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if ((login = getlogin()) == NULL)
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login = pwuid;
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if (strlen(tty) + 6 > sizeof(path))
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errx(EXIT_FAILURE, _("tty path %s too long"), tty);
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snprintf(path, sizeof(path), "/dev/%s", tty);
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if ((freopen(path, "w", stdout)) == NULL)
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err(EXIT_FAILURE, "%s", path);
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signal(SIGINT, done);
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signal(SIGHUP, done);
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/* print greeting */
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host = xgethostname();
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if (!host)
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host = xstrdup("???");
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now = time((time_t *) NULL);
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nows = ctime(&now);
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nows[16] = '\0';
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printf("\r\n\007\007\007");
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if (strcmp(login, pwuid))
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printf(_("Message from %s@%s (as %s) on %s at %s ..."),
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login, host, pwuid, mytty, nows + 11);
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else
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printf(_("Message from %s@%s on %s at %s ..."),
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login, host, mytty, nows + 11);
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free(host);
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printf("\r\n");
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while (fgets(line, sizeof(line), stdin) != NULL)
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wr_fputs(line);
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}
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/*
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* done - cleanup and exit
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*/
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static void __attribute__ ((__noreturn__))
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done(int dummy __attribute__ ((__unused__)))
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{
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printf("EOF\r\n");
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_exit(EXIT_SUCCESS);
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}
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/*
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* wr_fputs - like fputs(), but makes control characters visible and
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* turns \n into \r\n.
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*/
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void wr_fputs(char *s)
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{
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char c;
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#define PUTC(c) if (fputc_careful(c, stdout, '^') == EOF) \
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err(EXIT_FAILURE, _("carefulputc failed"));
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while (*s) {
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c = *s++;
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if (c == '\n')
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PUTC('\r');
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PUTC(c);
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}
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return;
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#undef PUTC
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}
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