summaryrefslogtreecommitdiffstats
path: root/tools/iminternal.c
blob: c4dd548cee65d951ac9a188dcd4664e452286aea (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
/* iminternal.c
 * This file set implements the internal messages input module for rsyslog.
 * Note: we currently do not have an input module spec, but
 * we will have one in the future. This module needs then to be
 * adapted.
 *
 * File begun on 2007-08-03 by RGerhards
 *
 * Copyright 2007-2022 Rainer Gerhards and 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 <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <signal.h>

#include "syslogd.h"
#include "linkedlist.h"
#include "iminternal.h"
#include "unicode-helper.h"

static linkedList_t llMsgs;
static pthread_mutex_t mutList = PTHREAD_MUTEX_INITIALIZER;


/* destructs an iminternal object
 */
static rsRetVal iminternalDestruct(iminternal_t *pThis)
{
	DEFiRet;

	if(pThis->pMsg != NULL)
		msgDestruct(&pThis->pMsg);

	free(pThis);

	RETiRet;
}


/* Construct an iminternal object
 */
static rsRetVal iminternalConstruct(iminternal_t **ppThis)
{
	DEFiRet;
	if((*ppThis = (iminternal_t*) calloc(1, sizeof(iminternal_t))) == NULL) {
		iRet = RS_RET_OUT_OF_MEMORY;
	}
	RETiRet;
}


/* add a message to the linked list
 * Note: the pMsg reference counter is not incremented. Consequently,
 * the caller must NOT decrement it. The caller actually hands over
 * full ownership of the pMsg object.
 */
rsRetVal iminternalAddMsg(smsg_t *pMsg)
{
	DEFiRet;
	iminternal_t *pThis = NULL;
	struct timespec to;
	int r;
	int is_locked = 0;

	/* we guard against deadlock, so we can guarantee rsyslog will never
	 * block due to internal messages. The 1 second timeout should be
	 * sufficient under all circumstances.
	 */
	to.tv_sec = time(NULL) + 1;
	to.tv_nsec = 0;
	#if !defined(__APPLE__)
	r = pthread_mutex_timedlock(&mutList, &to);
	#else
	r = pthread_mutex_trylock(&mutList); // must check
	#endif
	if(r != 0) {
		dbgprintf("iminternalAddMsg: timedlock for mutex failed with %d, msg %s\n",
			r, getMSG(pMsg));
		/* the message is lost, nothing we can do against this! */
		msgDestruct(&pMsg);
		ABORT_FINALIZE(RS_RET_ERR);
	}
	is_locked = 1;
	CHKiRet(iminternalConstruct(&pThis));
	pThis->pMsg = pMsg;
	CHKiRet(llAppend(&llMsgs,  NULL, (void*) pThis));

	if(PREFER_FETCH_32BIT(bHaveMainQueue)) {
		DBGPRINTF("signaling new internal message via SIGTTOU: '%s'\n",
			pThis->pMsg->pszRawMsg);
		kill(glblGetOurPid(), SIGTTOU);
	}

finalize_it:
	if(is_locked) {
		pthread_mutex_unlock(&mutList);
	}
	if(iRet != RS_RET_OK) {
		dbgprintf("iminternalAddMsg() error %d - can not otherwise report this error, message lost\n", iRet);
		if(pThis != NULL)
			iminternalDestruct(pThis);
	}

	RETiRet;
}


/* pull the first error message from the linked list, remove it
 * from the list and return it to the caller. The caller is
 * responsible for freeing the message!
 */
rsRetVal iminternalRemoveMsg(smsg_t **ppMsg)
{
	DEFiRet;
	iminternal_t *pThis;
	linkedListCookie_t llCookie = NULL;

	pthread_mutex_lock(&mutList);
	CHKiRet(llGetNextElt(&llMsgs, &llCookie, (void*)&pThis));
	if(!strcmp((char*)pThis->pMsg->pszHOSTNAME, "[localhost]")) {
		/* early (pre-conf) startup message detected, need to set real hostname now */
		MsgSetHOSTNAME(pThis->pMsg, glblGetLocalHostName(), ustrlen(glblGetLocalHostName()));
	}
	*ppMsg = pThis->pMsg;
	pThis->pMsg = NULL; /* we do no longer own it - important for destructor */

	if(llDestroyRootElt(&llMsgs) != RS_RET_OK) {
		dbgprintf("Root element of iminternal linked list could not be destroyed - there is "
			"nothing we can do against it, we ignore it for now. Things may go wild "
			"from here on. This is most probably a program logic error.\n");
	}

finalize_it:
	pthread_mutex_unlock(&mutList);
	RETiRet;
}


/* initialize the iminternal subsystem
 * must be called once at the start of the program
 */
rsRetVal modInitIminternal(void)
{
	DEFiRet;
	iRet = llInit(&llMsgs, iminternalDestruct, NULL, NULL);
	RETiRet;
}


/* de-initialize the iminternal subsystem
 * must be called once at the end of the program
 * Note: the error list must have been pulled first. We do
 * NOT care if there are any errors left - we simply destroy
 * them.
 */
rsRetVal modExitIminternal(void)
{
	DEFiRet;
	iRet = llDestroy(&llMsgs);
	RETiRet;
}