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rsyslog/tools/omusrmsg.c

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/* omusrmsg.c
* This is the implementation of the build-in output module for sending
* user messages.
*
* NOTE: read comments in module-template.h to understand how this file
* works!
*
* File begun on 2007-07-20 by RGerhards (extracted from syslogd.c, which at the
* time of the fork from sysklogd was under BSD license)
*
* Copyright 2007-2016 Adiscon GmbH.
*
* This file is part of rsyslog.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
* -or-
* see COPYING.ASL20 in the source distribution
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "config.h"
#include "rsyslog.h"
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <signal.h>
#include <ctype.h>
#include <sys/param.h>
#ifdef HAVE_UTMP_H
# include <utmp.h>
# define STRUCTUTMP struct utmp
# define UTNAME ut_name
#else
# include <utmpx.h>
# define STRUCTUTMP struct utmpx
# define UTNAME ut_user
#endif
#include <unistd.h>
#include <sys/uio.h>
#include <sys/stat.h>
#include <errno.h>
#if HAVE_FCNTL_H
#include <fcntl.h>
#else
#include <sys/msgbuf.h>
#endif
#if HAVE_PATHS_H
#include <paths.h>
#endif
#include "srUtils.h"
#include "stringbuf.h"
#include "syslogd-types.h"
#include "conf.h"
#include "omusrmsg.h"
#include "module-template.h"
#include "errmsg.h"
/* portability: */
#ifndef _PATH_DEV
# define _PATH_DEV "/dev/"
#endif
MODULE_TYPE_OUTPUT
MODULE_TYPE_NOKEEP
MODULE_CNFNAME("omusrmsg")
/* internal structures
*/
DEF_OMOD_STATIC_DATA
DEFobjCurrIf(errmsg)
typedef struct _instanceData {
int bIsWall; /* 1- is wall, 0 - individual users */
char uname[MAXUNAMES][UNAMESZ+1];
uchar *tplName;
} instanceData;
typedef struct wrkrInstanceData {
instanceData *pData;
} wrkrInstanceData_t;
typedef struct configSettings_s {
EMPTY_STRUCT
} configSettings_t;
static configSettings_t __attribute__((unused)) cs;
/* tables for interfacing with the v6 config system */
/* action (instance) parameters */
static struct cnfparamdescr actpdescr[] = {
{ "users", eCmdHdlrString, CNFPARAM_REQUIRED },
{ "template", eCmdHdlrGetWord, 0 }
};
static struct cnfparamblk actpblk =
{ CNFPARAMBLK_VERSION,
sizeof(actpdescr)/sizeof(struct cnfparamdescr),
actpdescr
};
BEGINinitConfVars /* (re)set config variables to default values */
CODESTARTinitConfVars
ENDinitConfVars
BEGINcreateInstance
CODESTARTcreateInstance
ENDcreateInstance
BEGINcreateWrkrInstance
CODESTARTcreateWrkrInstance
ENDcreateWrkrInstance
BEGINisCompatibleWithFeature
CODESTARTisCompatibleWithFeature
if(eFeat == sFEATURERepeatedMsgReduction)
iRet = RS_RET_OK;
ENDisCompatibleWithFeature
BEGINfreeInstance
CODESTARTfreeInstance
free(pData->tplName);
ENDfreeInstance
BEGINfreeWrkrInstance
CODESTARTfreeWrkrInstance
ENDfreeWrkrInstance
BEGINdbgPrintInstInfo
register int i;
CODESTARTdbgPrintInstInfo
for (i = 0; i < MAXUNAMES && *pData->uname[i]; i++)
dbgprintf("%s, ", pData->uname[i]);
ENDdbgPrintInstInfo
/**
* 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 OS_BSD
/* Since version 900007, FreeBSD has a POSIX compliant <utmpx.h> */
#if defined(__FreeBSD__) && (__FreeBSD_version >= 900007)
# define setutent(void) setutxent(void)
# define getutent(void) getutxent(void)
# define endutent(void) endutxent(void)
#else
static FILE *BSD_uf = NULL;
void setutent(void)
{
assert(BSD_uf == NULL);
if ((BSD_uf = fopen(_PATH_UTMP, "r")) == NULL) {
errmsg.LogError(errno, NO_ERRCODE, "error opening utmp %s", _PATH_UTMP);
return;
}
}
STRUCTUTMP* getutent(void)
{
static STRUCTUTMP 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 /* if defined(__FreeBSD__) */
#endif /* #ifdef OS_BSD */
/* 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/".
* rgerhards, 2008-07-04: changing the function to no longer use fork() but
* continue run on its thread instead.
*/
static rsRetVal wallmsg(uchar* pMsg, instanceData *pData)
{
uchar szErr[512];
char p[sizeof(_PATH_DEV) + UNAMESZ];
register int i;
int errnoSave;
int ttyf;
int wrRet;
STRUCTUTMP ut;
STRUCTUTMP *uptr;
struct stat statb;
DEFiRet;
assert(pMsg != NULL);
/* open the user login file */
setutent();
/* scan the user login file */
while((uptr = getutent())) {
memcpy(&ut, uptr, sizeof(ut));
/* is this slot used? */
if(ut.UTNAME[0] == '\0')
continue;
#ifndef OS_BSD
if(ut.ut_type != USER_PROCESS)
continue;
#endif
if(!(strncmp (ut.UTNAME,"LOGIN", 6))) /* paranoia */
continue;
/* should we send the message to this user? */
if(pData->bIsWall == 0) {
for(i = 0; i < MAXUNAMES; i++) {
if(!pData->uname[i][0]) {
i = MAXUNAMES;
break;
}
if(strncmp(pData->uname[i], ut.UTNAME, UNAMESZ) == 0)
break;
}
if(i == MAXUNAMES) /* user not found? */
continue; /* on to next user! */
}
/* compute the device name */
strcpy(p, _PATH_DEV);
strncat(p, ut.ut_line, UNAMESZ);
/* we must be careful when writing to the terminal. A terminal may block
* (for example, a user has pressed <ctl>-s). In that case, we can not
* wait indefinitely. So we need to use non-blocking I/O. In case we would
* block, we simply do not send the message, because that's the best we can
* do. -- rgerhards, 2008-07-04
*/
/* open the terminal */
if((ttyf = open(p, O_WRONLY|O_NOCTTY|O_NONBLOCK)) >= 0) {
if(fstat(ttyf, &statb) == 0 && (statb.st_mode & S_IWRITE)) {
wrRet = write(ttyf, pMsg, strlen((char*)pMsg));
if(Debug && wrRet == -1) {
/* we record the state to the debug log */
errnoSave = errno;
rs_strerror_r(errno, (char*)szErr, sizeof(szErr));
dbgprintf("write to terminal '%s' failed with [%d]:%s\n",
p, errnoSave, szErr);
}
}
close(ttyf);
}
}
/* close the user login file */
endutent();
RETiRet;
}
BEGINtryResume
CODESTARTtryResume
ENDtryResume
BEGINdoAction
CODESTARTdoAction
dbgprintf("\n");
iRet = wallmsg(ppString[0], pWrkrData->pData);
ENDdoAction
static void
populateUsers(instanceData *pData, es_str_t *usrs)
{
int i;
int iDst;
es_size_t iUsr;
es_size_t len;
uchar *c;
len = es_strlen(usrs);
c = es_getBufAddr(usrs);
pData->bIsWall = 0; /* write to individual users */
iUsr = 0;
for(i = 0 ; i < MAXUNAMES && iUsr < len ; ++i) {
for( iDst = 0
; iDst < UNAMESZ && iUsr < len && c[iUsr] != ','
; ++iDst, ++iUsr) {
pData->uname[i][iDst] = c[iUsr];
}
pData->uname[i][iDst] = '\0';
DBGPRINTF("omusrmsg: send to user '%s'\n", pData->uname[i]);
if(iUsr < len && c[iUsr] != ',') {
errmsg.LogError(0, RS_RET_ERR, "user name '%s...' too long - "
"ignored", pData->uname[i]);
--i;
++iUsr;
while(iUsr < len && c[iUsr] != ',')
++iUsr; /* skip to next name */
} else if(iDst == 0) {
errmsg.LogError(0, RS_RET_ERR, "no user name given - "
"ignored");
--i;
++iUsr;
while(iUsr < len && c[iUsr] != ',')
++iUsr; /* skip to next name */
}
if(iUsr < len) {
++iUsr; /* skip "," */
while(iUsr < len && isspace(c[iUsr]))
++iUsr; /* skip whitespace */
}
}
if(i == MAXUNAMES && iUsr != len) {
errmsg.LogError(0, RS_RET_ERR, "omusrmsg supports only up to %d "
"user names in a single action - all others have been ignored",
MAXUNAMES);
}
}
static inline void
setInstParamDefaults(instanceData *pData)
{
pData->bIsWall = 0;
pData->tplName = NULL;
}
BEGINnewActInst
struct cnfparamvals *pvals;
int i;
CODESTARTnewActInst
if((pvals = nvlstGetParams(lst, &actpblk, NULL)) == NULL) {
ABORT_FINALIZE(RS_RET_MISSING_CNFPARAMS);
}
CHKiRet(createInstance(&pData));
setInstParamDefaults(pData);
CODE_STD_STRING_REQUESTnewActInst(1)
for(i = 0 ; i < actpblk.nParams ; ++i) {
if(!pvals[i].bUsed)
continue;
if(!strcmp(actpblk.descr[i].name, "users")) {
if(!es_strbufcmp(pvals[i].val.d.estr, (uchar*)"*", 1)) {
pData->bIsWall = 1;
} else {
populateUsers(pData, pvals[i].val.d.estr);
}
} else if(!strcmp(actpblk.descr[i].name, "template")) {
pData->tplName = (uchar*)es_str2cstr(pvals[i].val.d.estr, NULL);
} else {
dbgprintf("omusrmsg: program error, non-handled "
"param '%s'\n", actpblk.descr[i].name);
}
}
if(pData->tplName == NULL) {
CHKiRet(OMSRsetEntry(*ppOMSR, 0,
(uchar*) strdup(pData->bIsWall ? " WallFmt" : " StdUsrMsgFmt"),
OMSR_NO_RQD_TPL_OPTS));
} else {
CHKiRet(OMSRsetEntry(*ppOMSR, 0,
(uchar*) strdup((char*) pData->tplName),
OMSR_NO_RQD_TPL_OPTS));
}
CODE_STD_FINALIZERnewActInst
cnfparamvalsDestruct(pvals, &actpblk);
ENDnewActInst
BEGINparseSelectorAct
es_str_t *usrs;
int bHadWarning;
CODESTARTparseSelectorAct
CODE_STD_STRING_REQUESTparseSelectorAct(1)
bHadWarning = 0;
if(!strncmp((char*) p, ":omusrmsg:", sizeof(":omusrmsg:") - 1)) {
p += sizeof(":omusrmsg:") - 1; /* eat indicator sequence (-1 because of '\0'!) */
} else {
if(!*p || !((*p >= 'a' && *p <= 'z') || (*p >= 'A' && *p <= 'Z')
|| (*p >= '0' && *p <= '9') || *p == '_' || *p == '.' || *p == '*')) {
ABORT_FINALIZE(RS_RET_CONFLINE_UNPROCESSED);
} else {
errmsg.LogMsg(0, RS_RET_OUTDATED_STMT, LOG_WARNING,
"action '%s' treated as ':omusrmsg:%s' - please "
"use ':omusrmsg:%s' syntax instead, '%s' will "
"not be supported in the future",
p, p, p, p);
bHadWarning = 1;
}
}
CHKiRet(createInstance(&pData));
if(*p == '*') { /* wall */
dbgprintf("write-all");
++p; /* eat '*' */
pData->bIsWall = 1; /* write to all users */
CHKiRet(cflineParseTemplateName(&p, *ppOMSR, 0, OMSR_NO_RQD_TPL_OPTS, (uchar*) " WallFmt"));
} else {
/* everything else is currently treated as a user name */
usrs = es_newStr(128);
while(*p && *p != ';') {
es_addChar(&usrs, *p);
++p;
}
populateUsers(pData, usrs);
es_deleteStr(usrs);
if((iRet = cflineParseTemplateName(&p, *ppOMSR, 0, OMSR_NO_RQD_TPL_OPTS, (uchar*)" StdUsrMsgFmt"))
!= RS_RET_OK)
goto finalize_it;
}
if(iRet == RS_RET_OK && bHadWarning)
iRet = RS_RET_OK_WARN;
CODE_STD_FINALIZERparseSelectorAct
ENDparseSelectorAct
BEGINmodExit
CODESTARTmodExit
ENDmodExit
BEGINqueryEtryPt
CODESTARTqueryEtryPt
CODEqueryEtryPt_STD_OMOD_QUERIES
CODEqueryEtryPt_STD_OMOD8_QUERIES
CODEqueryEtryPt_STD_CONF2_OMOD_QUERIES
ENDqueryEtryPt
BEGINmodInit(UsrMsg)
CODESTARTmodInit
INITLegCnfVars
*ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
CODEmodInit_QueryRegCFSLineHdlr
CHKiRet(objUse(errmsg, CORE_COMPONENT));
ENDmodInit
/* vim:set ai:
*/
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