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/* $OpenBSD: lockspool.c,v 1.21 2020/02/09 14:59:20 millert Exp $ */
/*
* Copyright (c) 1998 Theo de Raadt <deraadt@theos.com>
* Copyright (c) 1998 Todd C. Miller <millert@openbsd.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED ``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 AUTHORS 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.
*/
#include <signal.h>
#include <pwd.h>
#include <syslog.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <paths.h>
#include <stdlib.h>
#include <poll.h>
#include <err.h>
#include "mail.local.h"
void unhold(int);
void usage(void);
extern char *__progname;
int
main(int argc, char *argv[])
{
struct passwd *pw;
struct pollfd pfd;
ssize_t nread;
char *from, c;
int holdfd;
if (unveil(_PATH_MAILDIR, "rwc") == -1)
err(1, "unveil");
if (pledge("stdio rpath wpath getpw cpath fattr", NULL) == -1)
err(1, "pledge");
openlog(__progname, LOG_PERROR, LOG_MAIL);
if (argc != 1 && argc != 2)
usage();
if (argc == 2 && getuid() != 0)
merr(1, "you must be root to lock someone else's spool");
signal(SIGTERM, unhold);
signal(SIGINT, unhold);
signal(SIGHUP, unhold);
signal(SIGPIPE, unhold);
if (argc == 2)
pw = getpwnam(argv[1]);
else
pw = getpwuid(getuid());
if (pw == NULL)
exit (1);
from = pw->pw_name;
holdfd = getlock(from, pw);
if (holdfd == -1) {
write(STDOUT_FILENO, "0\n", 2);
exit (1);
}
write(STDOUT_FILENO, "1\n", 2);
/* wait for the other end of the pipe to close, then release the lock */
pfd.fd = STDIN_FILENO;
pfd.events = POLLIN;
do {
if (poll(&pfd, 1, INFTIM) == -1) {
if (errno != EINTR)
break;
}
do {
nread = read(STDIN_FILENO, &c, 1);
} while (nread == 1 || (nread == -1 && errno == EINTR));
} while (nread == -1 && errno == EAGAIN);
rellock();
exit (0);
}
/*ARGSUSED*/
void
unhold(int signo)
{
rellock();
_exit(0);
}
void
usage(void)
{
merr(1, "usage: %s [username]", __progname);
}
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