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/* omusrmsg.c
* This is the implementation of the build-in output module for sending
* user messages.
*
* File begun on 2007-07-20 by RGerhards (extracted from syslogd.c)
* This file is under development and has not yet arrived at being fully
* self-contained and a real object. So far, it is mostly an excerpt
* of the "old" message code without any modifications. However, it
* helps to have things at the right place one we go to the meat of it.
*
* Copyright 2007 Rainer Gerhards and Adiscon GmbH.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* A copy of the GPL can be found in the file "COPYING" in this distribution.
*/
#include "config.h"
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <signal.h>
#include <sys/param.h>
#include <utmp.h>
#include <unistd.h>
#include <sys/uio.h>
#include <sys/stat.h>
#include <setjmp.h>
#if HAVE_FCNTL_H
#include <fcntl.h>
#else
#include <sys/msgbuf.h>
#endif
#include "rsyslog.h"
#include "syslogd.h"
#include "syslogd-types.h"
#include "srUtils.h"
#include "omusrmsg.h"
jmp_buf ttybuf;
static void endtty()
{
longjmp(ttybuf, 1);
}
/**
* BSD setutent/getutent() replacement routines
* The following routines emulate setutent() and getutent() under
* BSD because they are not available there. We only emulate what we actually
* need! rgerhards 2005-03-18
*/
#ifdef BSD
static FILE *BSD_uf = NULL;
void setutent(void)
{
assert(BSD_uf == NULL);
if ((BSD_uf = fopen(_PATH_UTMP, "r")) == NULL) {
logerror(_PATH_UTMP);
return;
}
}
struct utmp* getutent(void)
{
static struct utmp st_utmp;
if(fread((char *)&st_utmp, sizeof(st_utmp), 1, BSD_uf) != 1)
return NULL;
return(&st_utmp);
}
void endutent(void)
{
fclose(BSD_uf);
BSD_uf = NULL;
}
#endif
/*
* WALLMSG -- Write a message to the world at large
*
* Write the specified message to either the entire
* world, or a list of approved users.
*
* rgerhards, 2005-10-19: applying the following sysklogd patch:
* Tue May 4 16:52:01 CEST 2004: Solar Designer <solar@openwall.com>
* Adjust the size of a variable to prevent a buffer overflow
* should _PATH_DEV ever contain something different than "/dev/".
*/
static void wallmsg(register selector_t *f)
{
char p[sizeof(_PATH_DEV) + UNAMESZ];
register int i;
int ttyf;
static int reenter = 0;
struct utmp ut;
struct utmp *uptr;
assert(f != NULL);
if (reenter++)
return;
iovCreate(f); /* init the iovec */
/* open the user login file */
setutent();
/*
* Might as well fork instead of using nonblocking I/O
* and doing notty().
*/
if (fork() == 0) {
signal(SIGTERM, SIG_DFL);
alarm(0);
# ifdef SIGTTOU
signal(SIGTTOU, SIG_IGN);
# endif
sigsetmask(0);
/* TODO: find a way to limit the max size of the message. hint: this
* should go into the template!
*/
/* rgerhards 2005-10-24: HINT: this code might be run in a seperate thread
* instead of a seperate process once we have multithreading...
*/
/* scan the user login file */
while ((uptr = getutent())) {
memcpy(&ut, uptr, sizeof(ut));
/* is this slot used? */
if (ut.ut_name[0] == '\0')
continue;
#ifndef BSD
if (ut.ut_type != USER_PROCESS)
continue;
#endif
if (!(strncmp (ut.ut_name,"LOGIN", 6))) /* paranoia */
continue;
/* should we send the message to this user? */
if (f->f_type == F_USERS) {
for (i = 0; i < MAXUNAMES; i++) {
if (!f->f_un.f_uname[i][0]) {
i = MAXUNAMES;
break;
}
if (strncmp(f->f_un.f_uname[i],
ut.ut_name, UNAMESZ) == 0)
break;
}
if (i >= MAXUNAMES)
continue;
}
/* compute the device name */
strcpy(p, _PATH_DEV);
strncat(p, ut.ut_line, UNAMESZ);
if (setjmp(ttybuf) == 0) {
(void) signal(SIGALRM, endtty);
(void) alarm(15);
/* open the terminal */
ttyf = open(p, O_WRONLY|O_NOCTTY);
if (ttyf >= 0) {
struct stat statb;
if (fstat(ttyf, &statb) == 0 &&
(statb.st_mode & S_IWRITE))
(void) writev(ttyf, f->f_iov, f->f_iIovUsed);
close(ttyf);
ttyf = -1;
}
}
(void) alarm(0);
}
exit(0); /* "good" exit - this terminates the child forked just for message delivery */
}
/* close the user login file */
endutent();
reenter = 0;
}
/* call the shell action
* returns 0 if it succeeds, something else otherwise
*/
int doActionUsrMsg(selector_t *f)
{
assert(f != NULL);
dprintf("\n");
wallmsg(f);
return 0;
}
/*
* vi:set ai:
*/
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