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Diffstat (limited to 'omusrmsg.c')
| -rw-r--r-- | omusrmsg.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/omusrmsg.c b/omusrmsg.c new file mode 100644 index 00000000..0d914888 --- /dev/null +++ b/omusrmsg.c @@ -0,0 +1,218 @@ +/* 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 "omshell.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, time_t now) +{ + assert(f != NULL); + + f->f_time = now; + dprintf("\n"); + wallmsg(f); + return 0; +} + +/* + * vi:set ai: + */ |