NetBSD/libexec/mail.local/mail.local.c

/*-
 * Copyright (c) 1990 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1990 The Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)mail.local.c	5.6 (Berkeley) 6/19/91";
#endif /* not lint */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <syslog.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <time.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "pathnames.h"

#define	FATAL		1
#define	NOTFATAL	0

int	deliver __P((int, char *));
void	err __P((int, const char *, ...));
void	notifybiff __P((char *));
int	store __P((char *));
void	usage __P((void));

main(argc, argv)
	int argc;
	char **argv;
{
	extern int optind;
	extern char *optarg;
	struct passwd *pw;
	int ch, fd, eval;
	uid_t uid;
	char *from;

	openlog("mail.local", LOG_PERROR, LOG_MAIL);

	from = NULL;
	while ((ch = getopt(argc, argv, "df:r:")) != EOF)
		switch(ch) {
		case 'd':		/* backward compatible */
			break;
		case 'f':
		case 'r':		/* backward compatible */
			if (from)
			    err(FATAL, "multiple -f options");
			from = optarg;
			break;
		case '?':
		default:
			usage();
		}
	argc -= optind;
	argv += optind;

	if (!*argv)
		usage();

	/*
	 * If from not specified, use the name from getlogin() if the
	 * uid matches, otherwise, use the name from the password file
	 * corresponding to the uid.
	 */
	uid = getuid();
	if (!from && (!(from = getlogin()) ||
	    !(pw = getpwnam(from)) || pw->pw_uid != uid))
		from = (pw = getpwuid(uid)) ? pw->pw_name : "???";

	fd = store(from);
	for (eval = 0; *argv; ++argv)
		eval |= deliver(fd, *argv);
	exit(eval);
}

store(from)
	char *from;
{
	FILE *fp;
	time_t tval;
	int fd, eline;
	char *tn, line[2048];

	tn = strdup(_PATH_LOCTMP);
	if ((fd = mkstemp(tn)) == -1 || !(fp = fdopen(fd, "w+")))
		err(FATAL, "unable to open temporary file");
	(void)unlink(tn);
	free(tn);

	(void)time(&tval);
	(void)fprintf(fp, "From %s %s", from, ctime(&tval));

	line[0] = '\0';
	for (eline = 1; fgets(line, sizeof(line), stdin);) {
		if (line[0] == '\n')
			eline = 1;
		else {
			if (eline && line[0] == 'F' && !bcmp(line, "From ", 5))
				(void)putc('>', fp);
			eline = 0;
		}
		(void)fprintf(fp, "%s", line);
		if (ferror(fp))
			break;
	}

	/* If message not newline terminated, need an extra. */
	if (!index(line, '\n'))
		(void)putc('\n', fp);
	/* Output a newline; note, empty messages are allowed. */
	(void)putc('\n', fp);

	(void)fflush(fp);
	if (ferror(fp))
		err(FATAL, "temporary file write error");
	return(fd);
}

deliver(fd, name)
	int fd;
	char *name;
{
	struct stat sb;
	struct passwd *pw;
	int created, mbfd, nr, nw, off, rval;
	char biffmsg[100], buf[8*1024], path[MAXPATHLEN];
	off_t curoff, lseek();

	/*
	 * Disallow delivery to unknown names -- special mailboxes can be
	 * handled in the sendmail aliases file.
	 */
	if (!(pw = getpwnam(name))) {
		err(NOTFATAL, "unknown name: %s", name);
		return(1);
	}

	(void)sprintf(path, "%s/%s", _PATH_MAILDIR, name);

	if (!(created = lstat(path, &sb)) &&
	    (sb.st_nlink != 1 || S_ISLNK(sb.st_mode))) {
		err(NOTFATAL, "%s: linked file", path);
		return(1);
	}

	/*
	 * There's a race here -- two processes think they both created
	 * the file.  This means the file cannot be unlinked.
	 */
	if ((mbfd =
	    open(path, O_APPEND|O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR)) < 0) {
		err(NOTFATAL, "%s: %s", path, strerror(errno));
		return(1);
	}

	rval = 0;
	/* XXX: Open should allow flock'ing the file; see 4.4BSD. */
	if (flock(mbfd, LOCK_EX)) {
		err(NOTFATAL, "%s: %s", path, strerror(errno));
		rval = 1;
		goto bad;
	}

	curoff = lseek(mbfd, 0L, SEEK_END);
	(void)sprintf(biffmsg, "%s@%ld\n", name, curoff);
	if (lseek(fd, 0L, SEEK_SET) == (off_t)-1) {
		err(FATAL, "temporary file: %s", strerror(errno));
		rval = 1;
		goto bad;
	}

	while ((nr = read(fd, buf, sizeof(buf))) > 0)
		for (off = 0; off < nr; nr -= nw, off += nw)
			if ((nw = write(mbfd, buf + off, nr)) < 0) {
				err(NOTFATAL, "%s: %s", path, strerror(errno));
				goto trunc;
			}
	if (nr < 0) {
		err(FATAL, "temporary file: %s", strerror(errno));
trunc:		(void)ftruncate(mbfd, curoff);
		rval = 1;
	}

	/*
	 * Set the owner and group.  Historically, binmail repeated this at
	 * each mail delivery.  We no longer do this, assuming that if the
	 * ownership or permissions were changed there was a reason for doing
	 * so.
	 */
bad:	if (created) 
		(void)fchown(mbfd, pw->pw_uid, pw->pw_gid);

	(void)fsync(mbfd);		/* Don't wait for update. */
	(void)close(mbfd);		/* Implicit unlock. */

	if (!rval)
		notifybiff(biffmsg);
	return(rval);
}

void
notifybiff(msg)
	char *msg;
{
	static struct sockaddr_in addr;
	static int f = -1;
	struct hostent *hp;
	struct servent *sp;
	int len;

	if (!addr.sin_family) {
		/* Be silent if biff service not available. */
		if (!(sp = getservbyname("biff", "udp")))
			return;
		if (!(hp = gethostbyname("localhost"))) {
			err(NOTFATAL, "localhost: %s", strerror(errno));
			return;
		}
		addr.sin_family = hp->h_addrtype;
		bcopy(hp->h_addr, &addr.sin_addr, hp->h_length);
		addr.sin_port = sp->s_port;
	}
	if (f < 0 && (f = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
		err(NOTFATAL, "socket: %s", strerror(errno));
		return;
	}
	len = strlen(msg) + 1;
	if (sendto(f, msg, len, 0, (struct sockaddr *)&addr, sizeof(addr))
	    != len)
		err(NOTFATAL, "sendto biff: %s", strerror(errno));
}

void
usage()
{
	err(FATAL, "usage: mail.local [-f from] user ...");
}

#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

void
#if __STDC__
err(int isfatal, const char *fmt, ...)
#else
err(isfatal, fmt)
	int isfatal;
	char *fmt;
	va_dcl
#endif
{
	va_list ap;
#if __STDC__
	va_start(ap, fmt);
#else
	va_start(ap);
#endif
	vsyslog(LOG_ERR, fmt, ap);
	va_end(ap);
	if (isfatal)
		exit(1);
}