summaryrefslogtreecommitdiffstats
path: root/omfile.c
blob: f2d7814a12cefdf3283348f93e32ca27714c5c24 (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
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
/* omfile.c
 * This is the implementation of the build-in file output module.
 *
 * Handles: F_CONSOLE, F_TTY, F_FILE, F_PIPE
 *
 * File begun on 2007-07-21 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 <time.h>
#include <assert.h>
#include <errno.h>

#include <unistd.h>
#include <sys/file.h>
//#include <sys/param.h>

#include "rsyslog.h"
#include "syslogd.h"
#include "syslogd-types.h"
#include "srUtils.h"
#include "template.h"
#include "omfile.h"


/* rgerhards 2005-06-21: Try to resolve a size limit
 * situation. This first runs the command, and then
 * checks if we are still above the treshold.
 * returns 0 if ok, 1 otherwise
 * TODO: consider moving the initial check in here, too
 */
int resolveFileSizeLimit(selector_t *f)
{
	uchar *pParams;
	uchar *pCmd;
	uchar *p;
	off_t actualFileSize;
	assert(f != NULL);

	if(f->f_un.f_file.f_sizeLimitCmd == NULL)
		return 1; /* nothing we can do in this case... */
	
	/* the execProg() below is probably not great, but at least is is
	 * fairly secure now. Once we change the way file size limits are
	 * handled, we should also revisit how this command is run (and
	 * with which parameters).   rgerhards, 2007-07-20
	 */
	/* we first check if we have command line parameters. We assume this, 
	 * when we have a space in the program name. If we find it, everything after
	 * the space is treated as a single argument.
	 */
	if((pCmd = (uchar*)strdup((char*)f->f_un.f_file.f_sizeLimitCmd)) == NULL) {
		/* there is not much we can do - we make syslogd close the file in this case */
		glblHadMemShortage = 1;
		return 1;
		}

	for(p = pCmd ; *p && *p != ' ' ; ++p) {
		/* JUST SKIP */
	}

	if(*p == ' ') {
		*p = '\0'; /* pretend string-end */
		pParams = p+1;
	} else
		pParams = NULL;

	execProg(pCmd, 1, pParams);

	f->f_file = open(f->f_un.f_file.f_fname, O_WRONLY|O_APPEND|O_CREAT|O_NOCTTY,
			f->f_un.f_file.fCreateMode);

	actualFileSize = lseek(f->f_file, 0, SEEK_END);
	if(actualFileSize >= f->f_un.f_file.f_sizeLimit) {
		/* OK, it didn't work out... */
		return 1;
		}

	return 0;
}


/* This function deletes an entry from the dynamic file name
 * cache. A pointer to the cache must be passed in as well
 * as the index of the to-be-deleted entry. This index may
 * point to an unallocated entry, in whcih case the
 * function immediately returns. Parameter bFreeEntry is 1
 * if the entry should be free()ed and 0 if not.
 */
static void dynaFileDelCacheEntry(dynaFileCacheEntry **pCache, int iEntry, int bFreeEntry)
{
	assert(pCache != NULL);

	if(pCache[iEntry] == NULL)
		return;

	dprintf("Removed entry %d for file '%s' from dynaCache.\n", iEntry,
		pCache[iEntry]->pName == NULL ? "[OPEN FAILED]" : (char*)pCache[iEntry]->pName);
	/* if the name is NULL, this is an improperly initilized entry which
	 * needs to be discarded. In this case, neither the file is to be closed
	 * not the name to be freed.
	 */
	if(pCache[iEntry]->pName != NULL) {
		close(pCache[iEntry]->fd);
		free(pCache[iEntry]->pName);
		pCache[iEntry]->pName = NULL;
	}

	if(bFreeEntry) {
		free(pCache[iEntry]);
		pCache[iEntry] = NULL;
	}
}


/* This function frees the dynamic file name cache.
 */
static void dynaFileFreeCache(selector_t *f)
{
	register int i;
	assert(f != NULL);

	for(i = 0 ; i < f->f_un.f_file.iCurrCacheSize ; ++i) {
		dynaFileDelCacheEntry(f->f_un.f_file.dynCache, i, 1);
	}

	free(f->f_un.f_file.dynCache);
}


/* This function handles dynamic file names. It generates a new one
 * based on the current message, checks if that file is already open
 * and, if not, does everything needed to switch to the new one.
 * Function returns 0 if all went well and non-zero otherwise.
 * On successful return f->f_file must point to the correct file to
 * be written.
 * This is a helper to writeFile(). rgerhards, 2007-07-03
 */
static int prepareDynFile(selector_t *f)
{
	uchar *newFileName;
	time_t ttOldest; /* timestamp of oldest element */
	int iOldest;
	int i;
	int iFirstFree;
	dynaFileCacheEntry **pCache;

	assert(f != NULL);
	if((newFileName = tplToString(f->f_un.f_file.pTpl, f->f_pMsg)) == NULL) {
		/* memory shortage - there is nothing we can do to resolve it.
		 * We silently ignore it, this is probably the best we can do.
		 */
		glblHadMemShortage = TRUE;
		dprintf("prepareDynfile(): could not create file name, discarding this request\n");
		return -1;
	}

	pCache = f->f_un.f_file.dynCache;

	/* first check, if we still have the current file
	 * I *hope* this will be a performance enhancement.
	 */
	if(   (f->f_un.f_file.iCurrElt != -1)
	   && !strcmp((char*) newFileName,
	              (char*) pCache[f->f_un.f_file.iCurrElt])) {
	   	/* great, we are all set */
		free(newFileName);
		pCache[f->f_un.f_file.iCurrElt]->lastUsed = time(NULL); /* update timestamp for LRU */
		return 0;
	}

	/* ok, no luck. Now let's search the table if we find a matching spot.
	 * While doing so, we also prepare for creation of a new one.
	 */
	iFirstFree = -1; /* not yet found */
	iOldest = 0; /* we assume the first element to be the oldest - that will change as we loop */
	ttOldest = time(NULL) + 1; /* there must always be an older one */
	for(i = 0 ; i < f->f_un.f_file.iCurrCacheSize ; ++i) {
		if(pCache[i] == NULL) {
			if(iFirstFree == -1)
				iFirstFree = i;
		} else { /* got an element, let's see if it matches */
			if(!strcmp((char*) newFileName, (char*) pCache[i]->pName)) {
				/* we found our element! */
				f->f_file = pCache[i]->fd;
				f->f_un.f_file.iCurrElt = i;
				free(newFileName);
				pCache[i]->lastUsed = time(NULL); /* update timestamp for LRU */
				return 0;
			}
			/* did not find it - so lets keep track of the counters for LRU */
			if(pCache[i]->lastUsed < ttOldest) {
				ttOldest = pCache[i]->lastUsed;
				iOldest = i;
				}
		}
	}

	/* we have not found an entry */
	if(iFirstFree == -1 && (f->f_un.f_file.iCurrCacheSize < f->f_un.f_file.iDynaFileCacheSize)) {
		/* there is space left, so set it to that index */
		iFirstFree = f->f_un.f_file.iCurrCacheSize++;
	}

	if(iFirstFree == -1) {
		dynaFileDelCacheEntry(pCache, iOldest, 0);
		iFirstFree = iOldest; /* this one *is* now free ;) */
	} else {
		/* we need to allocate memory for the cache structure */
		pCache[iFirstFree] = (dynaFileCacheEntry*) calloc(1, sizeof(dynaFileCacheEntry));
		if(pCache[iFirstFree] == NULL) {
			glblHadMemShortage = TRUE;
			dprintf("prepareDynfile(): could not alloc mem, discarding this request\n");
			free(newFileName);
			return -1;
		}
	}

	/* Ok, we finally can open the file */
	if(access((char*)newFileName, F_OK) == 0) {
		/* file already exists */
		f->f_file = open((char*) newFileName, O_WRONLY|O_APPEND|O_CREAT|O_NOCTTY,
				f->f_un.f_file.fCreateMode);
	} else {
		/* file does not exist, create it (and eventually parent directories */
		if(f->f_un.f_file.bCreateDirs) {
			/* we fist need to create parent dirs if they are missing
			 * We do not report any errors here ourselfs but let the code
			 * fall through to error handler below.
			 */
			if(makeFileParentDirs(newFileName, strlen((char*)newFileName),
			     f->f_un.f_file.fDirCreateMode, f->f_un.f_file.dirUID,
			     f->f_un.f_file.dirGID, f->f_un.f_file.bFailOnChown) == 0) {
				f->f_file = open((char*) newFileName, O_WRONLY|O_APPEND|O_CREAT|O_NOCTTY,
						f->f_un.f_file.fCreateMode);
				if(f->f_file != -1) {
					/* check and set uid/gid */
					if(f->f_un.f_file.fileUID != (uid_t)-1 || f->f_un.f_file.fileGID != (gid_t) -1) {
						/* we need to set owner/group */
						if(fchown(f->f_file, f->f_un.f_file.fileUID,
						          f->f_un.f_file.fileGID) != 0) {
							if(f->f_un.f_file.bFailOnChown) {
								int eSave = errno;
								close(f->f_file);
								f->f_file = -1;
								errno = eSave;
							}
							/* we will silently ignore the chown() failure
							 * if configured to do so.
							 */
						}
					}
				}
			}
		}
	}

	/* file is either open now or an error state set */
	if(f->f_file == -1) {
		/* do not report anything if the message is an internally-generated
		 * message. Otherwise, we could run into a never-ending loop. The bad
		 * news is that we also lose errors on startup messages, but so it is.
		 */
		if(f->f_pMsg->msgFlags & INTERNAL_MSG)
			dprintf("Could not open dynaFile, discarding message\n");
		else
			logerrorSz("Could not open dynamic file '%s' - discarding message", (char*)newFileName);
		free(newFileName);
		dynaFileDelCacheEntry(pCache, iFirstFree, 1);
		return -1;
	}

	pCache[iFirstFree]->fd = f->f_file;
	pCache[iFirstFree]->pName = newFileName;
	pCache[iFirstFree]->lastUsed = time(NULL);
	f->f_un.f_file.iCurrElt = iFirstFree;
	dprintf("Added new entry %d for file cache, file '%s'.\n",
		iFirstFree, newFileName);

	return 0;
}


/* rgerhards 2004-11-11: write to a file output. This
 * will be called for all outputs using file semantics,
 * for example also for pipes.
 */
void writeFile(selector_t *f)
{
	off_t actualFileSize;

	assert(f != NULL);

	/* first check if we have a dynamic file name and, if so,
	 * check if it still is ok or a new file needs to be created
	 */
	if(f->f_un.f_file.bDynamicName) {
		if(prepareDynFile(f) != 0)
			return;
	}

	/* create the message based on format specified */
	iovCreate(f);
again:
	/* check if we have a file size limit and, if so,
	 * obey to it.
	 */
	if(f->f_un.f_file.f_sizeLimit != 0) {
		actualFileSize = lseek(f->f_file, 0, SEEK_END);
		if(actualFileSize >= f->f_un.f_file.f_sizeLimit) {
			char errMsg[256];
			/* for now, we simply disable a file once it is
			 * beyond the maximum size. This is better than having
			 * us aborted by the OS... rgerhards 2005-06-21
			 */
			(void) close(f->f_file);
			/* try to resolve the situation */
			if(resolveFileSizeLimit(f) != 0) {
				/* didn't work out, so disable... */
				f->f_type = F_UNUSED;
				snprintf(errMsg, sizeof(errMsg),
					 "no longer writing to file %s; grown beyond configured file size of %lld bytes, actual size %lld - configured command did not resolve situation",
					 f->f_un.f_file.f_fname, (long long) f->f_un.f_file.f_sizeLimit, (long long) actualFileSize);
				errno = 0;
				logerror(errMsg);
				return;
			} else {
				snprintf(errMsg, sizeof(errMsg),
					 "file %s had grown beyond configured file size of %lld bytes, actual size was %lld - configured command resolved situation",
					 f->f_un.f_file.f_fname, (long long) f->f_un.f_file.f_sizeLimit, (long long) actualFileSize);
				errno = 0;
				logerror(errMsg);
			}
		}
	}

	if (writev(f->f_file, f->f_iov, f->f_iIovUsed) < 0) {
		int e = errno;

		/* If a named pipe is full, just ignore it for now
		   - mrn 24 May 96 */
		if (f->f_type == F_PIPE && e == EAGAIN)
			return;

		/* If the filesystem is filled up, just ignore
		 * it for now and continue writing when possible
		 * based on patch for sysklogd by Martin Schulze on 2007-05-24
		 */
		if (f->f_type == F_FILE && e == ENOSPC)
			return;

		(void) close(f->f_file);
		/*
		 * Check for EBADF on TTY's due to vhangup()
		 * Linux uses EIO instead (mrn 12 May 96)
		 */
		if ((f->f_type == F_TTY || f->f_type == F_CONSOLE)
#ifdef linux
			&& e == EIO) {
#else
			&& e == EBADF) {
#endif
			f->f_file = open(f->f_un.f_file.f_fname, O_WRONLY|O_APPEND|O_NOCTTY);
			if (f->f_file < 0) {
				f->f_type = F_UNUSED;
				logerror(f->f_un.f_file.f_fname);
			} else {
				untty();
				goto again;
			}
		} else {
			f->f_type = F_UNUSED;
			errno = e;
			logerror(f->f_un.f_file.f_fname);
		}
	} else if (f->f_flags & SYNC_FILE)
		fsync(f->f_file);
}


/* free an instance
 * returns 0 if it succeeds, something else otherwise
 */
int freeInstanceFile(selector_t *f)
{
	assert(f != NULL);
	if(f->f_un.f_file.bDynamicName) {
		dynaFileFreeCache(f);
	} else 
		close(f->f_file);
	return 0;
}


/* call the shell action
 * returns 0 if it succeeds, something else otherwise
 */
int doActionFile(selector_t *f)
{
	assert(f != NULL);

	/* f->f_file == -1 is an indicator that the we couldn't
	 * open the file at startup. For dynaFiles, this is ok,
	 * all others are doomed.
	 */
	if(f->f_un.f_file.bDynamicName || (f->f_file != -1))
		writeFile(f);
	return 0;
}
/*
 * vi:set ai:
 */