xref: /freebsd/contrib/ntp/ntpd/ntp_filegen.c (revision cd0d51baaa4509a1db83251a601d34404d20c990)
1 /*
2  * ntp_filegen.c,v 3.12 1994/01/25 19:06:11 kardel Exp
3  *
4  *  implements file generations support for NTP
5  *  logfiles and statistic files
6  *
7  *
8  * Copyright (C) 1992, 1996 by Rainer Pruy
9  * Friedrich-Alexander Universitaet Erlangen-Nuernberg, Germany
10  *
11  * This code may be modified and used freely
12  * provided credits remain intact.
13  */
14 
15 #ifdef HAVE_CONFIG_H
16 # include <config.h>
17 #endif
18 
19 #include <stdio.h>
20 #include <sys/types.h>
21 #include <sys/stat.h>
22 
23 #include "ntpd.h"
24 #include "ntp_io.h"
25 #include "ntp_string.h"
26 #include "ntp_calendar.h"
27 #include "ntp_filegen.h"
28 #include "ntp_stdlib.h"
29 
30 /*
31  * NTP is intended to run long periods of time without restart.
32  * Thus log and statistic files generated by NTP will grow large.
33  *
34  * this set of routines provides a central interface
35  * to generating files using file generations
36  *
37  * the generation of a file is changed according to file generation type
38  */
39 
40 
41 /*
42  * redefine this if your system dislikes filename suffixes like
43  * X.19910101 or X.1992W50 or ....
44  */
45 #define SUFFIX_SEP '.'
46 
47 static	void	filegen_open	(FILEGEN *, u_int32, const time_t*);
48 static	int	valid_fileref	(const char *, const char *);
49 static	void	filegen_init	(const char *, const char *, FILEGEN *);
50 #ifdef	DEBUG
51 static	void	filegen_uninit		(FILEGEN *);
52 #endif	/* DEBUG */
53 
54 
55 /*
56  * filegen_init
57  */
58 
59 static void
60 filegen_init(
61 	const char *	dir,
62 	const char *	fname,
63 	FILEGEN *	fgp
64 	)
65 {
66 	fgp->fp = NULL;
67 	fgp->dir = estrdup(dir);
68 	fgp->fname = estrdup(fname);
69 	fgp->id_lo = 0;
70 	fgp->id_hi = 0;
71 	fgp->type = FILEGEN_DAY;
72 	fgp->flag = FGEN_FLAG_LINK; /* not yet enabled !!*/
73 }
74 
75 
76 /*
77  * filegen_uninit - free memory allocated by filegen_init
78  */
79 #ifdef DEBUG
80 static void
81 filegen_uninit(
82 	FILEGEN *fgp
83 	)
84 {
85 	free(fgp->dir);
86 	free(fgp->fname);
87 }
88 #endif
89 
90 
91 /*
92  * open a file generation according to the current settings of gen
93  * will also provide a link to basename if requested to do so
94  */
95 
96 static void
97 filegen_open(
98 	FILEGEN *	gen,
99 	u_int32		stamp,
100 	const time_t *	pivot
101 	)
102 {
103 	char *savename;	/* temp store for name collision handling */
104 	char *fullname;	/* name with any designation extension */
105 	char *filename;	/* name without designation extension */
106 	char *suffix;	/* where to print suffix extension */
107 	u_int len, suflen;
108 	FILE *fp;
109 	struct calendar cal;
110 	struct isodate	iso;
111 
112 	/* get basic filename in buffer, leave room for extensions */
113 	len = strlen(gen->dir) + strlen(gen->fname) + 65;
114 	filename = emalloc(len);
115 	fullname = emalloc(len);
116 	savename = NULL;
117 	snprintf(filename, len, "%s%s", gen->dir, gen->fname);
118 
119 	/* where to place suffix */
120 	suflen = strlcpy(fullname, filename, len);
121 	suffix = fullname + suflen;
122 	suflen = len - suflen;
123 
124 	/* last octet of fullname set to '\0' for truncation check */
125 	fullname[len - 1] = '\0';
126 
127 	switch (gen->type) {
128 
129 	default:
130 		msyslog(LOG_ERR,
131 			"unsupported file generations type %d for "
132 			"\"%s\" - reverting to FILEGEN_NONE",
133 			gen->type, filename);
134 		gen->type = FILEGEN_NONE;
135 		break;
136 
137 	case FILEGEN_NONE:
138 		/* no suffix, all set */
139 		break;
140 
141 	case FILEGEN_PID:
142 		gen->id_lo = getpid();
143 		gen->id_hi = 0;
144 		snprintf(suffix, suflen, "%c#%ld",
145 			 SUFFIX_SEP, gen->id_lo);
146 		break;
147 
148 	case FILEGEN_DAY:
149 		/*
150 		 * You can argue here in favor of using MJD, but I
151 		 * would assume it to be easier for humans to interpret
152 		 * dates in a format they are used to in everyday life.
153 		 */
154 		ntpcal_ntp_to_date(&cal, stamp, pivot);
155 		snprintf(suffix, suflen, "%c%04d%02d%02d",
156 			 SUFFIX_SEP, cal.year, cal.month, cal.monthday);
157 		cal.hour = cal.minute = cal.second = 0;
158 		gen->id_lo = ntpcal_date_to_ntp(&cal);
159 		gen->id_hi = (u_int32)(gen->id_lo + SECSPERDAY);
160 		break;
161 
162 	case FILEGEN_WEEK:
163 		isocal_ntp_to_date(&iso, stamp, pivot);
164 		snprintf(suffix, suflen, "%c%04dw%02d",
165 			 SUFFIX_SEP, iso.year, iso.week);
166 		iso.hour = iso.minute = iso.second = 0;
167 		iso.weekday = 1;
168 		gen->id_lo = isocal_date_to_ntp(&iso);
169 		gen->id_hi = (u_int32)(gen->id_lo + 7 * SECSPERDAY);
170 		break;
171 
172 	case FILEGEN_MONTH:
173 		ntpcal_ntp_to_date(&cal, stamp, pivot);
174 		snprintf(suffix, suflen, "%c%04d%02d",
175 			 SUFFIX_SEP, cal.year, cal.month);
176 		cal.hour = cal.minute = cal.second = 0;
177 		cal.monthday = 1;
178 		gen->id_lo = ntpcal_date_to_ntp(&cal);
179 		cal.month++;
180 		gen->id_hi = ntpcal_date_to_ntp(&cal);
181 		break;
182 
183 	case FILEGEN_YEAR:
184 		ntpcal_ntp_to_date(&cal, stamp, pivot);
185 		snprintf(suffix, suflen, "%c%04d",
186 			 SUFFIX_SEP, cal.year);
187 		cal.hour = cal.minute = cal.second = 0;
188 		cal.month = cal.monthday = 1;
189 		gen->id_lo = ntpcal_date_to_ntp(&cal);
190 		cal.year++;
191 		gen->id_hi = ntpcal_date_to_ntp(&cal);
192 		break;
193 
194 	case FILEGEN_AGE:
195 		gen->id_lo = current_time - (current_time % SECSPERDAY);
196 		gen->id_hi = gen->id_lo + SECSPERDAY;
197 		snprintf(suffix, suflen, "%ca%08ld",
198 			 SUFFIX_SEP, gen->id_lo);
199 	}
200 
201 	/* check possible truncation */
202 	if ('\0' != fullname[len - 1]) {
203 		fullname[len - 1] = '\0';
204 		msyslog(LOG_ERR, "logfile name truncated: \"%s\"",
205 			fullname);
206 	}
207 
208 	if (FILEGEN_NONE != gen->type) {
209 		/*
210 		 * check for existence of a file with name 'basename'
211 		 * as we disallow such a file
212 		 * if FGEN_FLAG_LINK is set create a link
213 		 */
214 		struct stat stats;
215 		/*
216 		 * try to resolve name collisions
217 		 */
218 		static u_long conflicts = 0;
219 
220 #ifndef	S_ISREG
221 #define	S_ISREG(mode)	(((mode) & S_IFREG) == S_IFREG)
222 #endif
223 		if (stat(filename, &stats) == 0) {
224 			/* Hm, file exists... */
225 			if (S_ISREG(stats.st_mode)) {
226 				if (stats.st_nlink <= 1)	{
227 					/*
228 					 * Oh, it is not linked - try to save it
229 					 */
230 					savename = emalloc(len);
231 					snprintf(savename, len,
232 						"%s%c%dC%lu",
233 						filename, SUFFIX_SEP,
234 						(int)getpid(), conflicts++);
235 
236 					if (rename(filename, savename) != 0)
237 						msyslog(LOG_ERR,
238 							"couldn't save %s: %m",
239 							filename);
240 					free(savename);
241 				} else {
242 					/*
243 					 * there is at least a second link to
244 					 * this file.
245 					 * just remove the conflicting one
246 					 */
247 					if (
248 #if !defined(VMS)
249 						unlink(filename) != 0
250 #else
251 						delete(filename) != 0
252 #endif
253 						)
254 						msyslog(LOG_ERR,
255 							"couldn't unlink %s: %m",
256 							filename);
257 				}
258 			} else {
259 				/*
260 				 * Ehh? Not a regular file ?? strange !!!!
261 				 */
262 				msyslog(LOG_ERR,
263 					"expected regular file for %s "
264 					"(found mode 0%lo)",
265 					filename,
266 					(unsigned long)stats.st_mode);
267 			}
268 		} else {
269 			/*
270 			 * stat(..) failed, but it is absolutely correct for
271 			 * 'basename' not to exist
272 			 */
273 			if (ENOENT != errno)
274 				msyslog(LOG_ERR, "stat(%s) failed: %m",
275 						 filename);
276 		}
277 	}
278 
279 	/*
280 	 * now, try to open new file generation...
281 	 */
282 	DPRINTF(4, ("opening filegen (type=%d/stamp=%u) \"%s\"\n",
283 		    gen->type, stamp, fullname));
284 
285 	fp = fopen(fullname, "a");
286 
287 	if (NULL == fp)	{
288 		/* open failed -- keep previous state
289 		 *
290 		 * If the file was open before keep the previous generation.
291 		 * This will cause output to end up in the 'wrong' file,
292 		 * but I think this is still better than losing output
293 		 *
294 		 * ignore errors due to missing directories
295 		 */
296 
297 		if (ENOENT != errno)
298 			msyslog(LOG_ERR, "can't open %s: %m", fullname);
299 	} else {
300 		if (NULL != gen->fp) {
301 			fclose(gen->fp);
302 			gen->fp = NULL;
303 		}
304 		gen->fp = fp;
305 
306 		if (gen->flag & FGEN_FLAG_LINK) {
307 			/*
308 			 * need to link file to basename
309 			 * have to use hardlink for now as I want to allow
310 			 * gen->basename spanning directory levels
311 			 * this would make it more complex to get the correct
312 			 * fullname for symlink
313 			 *
314 			 * Ok, it would just mean taking the part following
315 			 * the last '/' in the name.... Should add it later....
316 			 */
317 
318 			/* Windows NT does not support file links -Greg Schueman 1/18/97 */
319 
320 #if defined(SYS_WINNT) || defined(SYS_VXWORKS)
321 			SetLastError(0); /* On WinNT, don't support FGEN_FLAG_LINK */
322 #elif defined(VMS)
323 			errno = 0; /* On VMS, don't support FGEN_FLAG_LINK */
324 #else  /* not (VMS) / VXWORKS / WINNT ; DO THE LINK) */
325 			if (link(fullname, filename) != 0)
326 				if (EEXIST != errno)
327 					msyslog(LOG_ERR,
328 						"can't link(%s, %s): %m",
329 						fullname, filename);
330 #endif /* SYS_WINNT || VXWORKS */
331 		}		/* flags & FGEN_FLAG_LINK */
332 	}			/* else fp == NULL */
333 
334 	free(filename);
335 	free(fullname);
336 	return;
337 }
338 
339 /*
340  * this function sets up gen->fp to point to the correct
341  * generation of the file for the time specified by 'now'
342  *
343  * 'now' usually is interpreted as second part of a l_fp as is in the cal...
344  * library routines
345  */
346 
347 void
348 filegen_setup(
349 	FILEGEN *	gen,
350 	u_int32		now
351 	)
352 {
353 	int	current;
354 	time_t	pivot;
355 
356 	if (!(gen->flag & FGEN_FLAG_ENABLED)) {
357 		if (NULL != gen->fp) {
358 			fclose(gen->fp);
359 			gen->fp = NULL;
360 		}
361 		return;
362 	}
363 
364 	switch (gen->type) {
365 
366 	default:
367 	case FILEGEN_NONE:
368 		current = TRUE;
369 		break;
370 
371 	case FILEGEN_PID:
372 		current = ((int)gen->id_lo == getpid());
373 		break;
374 
375 	case FILEGEN_AGE:
376 		current = (gen->id_lo <= current_time) &&
377 			  (gen->id_hi > current_time);
378 		break;
379 
380 	case FILEGEN_DAY:
381 	case FILEGEN_WEEK:
382 	case FILEGEN_MONTH:
383 	case FILEGEN_YEAR:
384 		current = (gen->id_lo <= now) &&
385 			  (gen->id_hi > now);
386 		break;
387 	}
388 	/*
389 	 * try to open file if not yet open
390 	 * reopen new file generation file on change of generation id
391 	 */
392 	if (NULL == gen->fp || !current) {
393 		DPRINTF(1, ("filegen  %0x %u\n", gen->type, now));
394 		pivot = time(NULL);
395 		filegen_open(gen, now, &pivot);
396 	}
397 }
398 
399 
400 /*
401  * change settings for filegen files
402  */
403 void
404 filegen_config(
405 	FILEGEN *	gen,
406 	const char *	dir,
407 	const char *	fname,
408 	u_int		type,
409 	u_int		flag
410 	)
411 {
412 	int file_existed;
413 	l_fp now;
414 
415 
416 	/*
417 	 * if nothing would be changed...
418 	 */
419 	if (strcmp(dir, gen->dir) == 0 && strcmp(fname, gen->fname) == 0
420 	    && type == gen->type && flag == gen->flag)
421 		return;
422 
423 	/*
424 	 * validate parameters
425 	 */
426 	if (!valid_fileref(dir, fname))
427 		return;
428 
429 	if (NULL != gen->fp) {
430 		fclose(gen->fp);
431 		gen->fp = NULL;
432 		file_existed = TRUE;
433 	} else {
434 		file_existed = FALSE;
435 	}
436 
437 	DPRINTF(3, ("configuring filegen:\n"
438 		    "\tdir:\t%s -> %s\n"
439 		    "\tfname:\t%s -> %s\n"
440 		    "\ttype:\t%d -> %d\n"
441 		    "\tflag: %x -> %x\n",
442 		    gen->dir, dir,
443 		    gen->fname, fname,
444 		    gen->type, type,
445 		    gen->flag, flag));
446 
447 	if (strcmp(gen->dir, dir) != 0) {
448 		free(gen->dir);
449 		gen->dir = estrdup(dir);
450 	}
451 
452 	if (strcmp(gen->fname, fname) != 0) {
453 		free(gen->fname);
454 		gen->fname = estrdup(fname);
455 	}
456 	gen->type = (u_char)type;
457 	gen->flag = (u_char)flag;
458 
459 	/*
460 	 * make filegen use the new settings
461 	 * special action is only required when a generation file
462 	 * is currently open
463 	 * otherwise the new settings will be used anyway at the next open
464 	 */
465 	if (file_existed) {
466 		get_systime(&now);
467 		filegen_setup(gen, now.l_ui);
468 	}
469 }
470 
471 
472 /*
473  * check whether concatenating prefix and basename
474  * yields a legal filename
475  */
476 static int
477 valid_fileref(
478 	const char *	dir,
479 	const char *	fname
480 	)
481 {
482 	/*
483 	 * dir cannot be changed dynamically
484 	 * (within the context of filegen)
485 	 * so just reject basenames containing '..'
486 	 *
487 	 * ASSUMPTION:
488 	 *		file system parts 'below' dir may be
489 	 *		specified without infringement of security
490 	 *
491 	 *		restricting dir to legal values
492 	 *		has to be ensured by other means
493 	 * (however, it would be possible to perform some checks here...)
494 	 */
495 	const char *p;
496 
497 	/*
498 	 * Just to catch, dumb errors opening up the world...
499 	 */
500 	if (NULL == dir || '\0' == dir[0])
501 		return FALSE;
502 
503 	if (NULL == fname)
504 		return FALSE;
505 
506 #ifdef SYS_WINNT
507 	/*
508 	 * Windows treats / equivalent to \, reject any / to ensure
509 	 * check below for DIR_SEP (\ on windows) are adequate.
510 	 */
511 	if (strchr(fname, '/')) {
512 		msyslog(LOG_ERR,
513 			"filegen filenames must not contain '/': %s",
514 			fname);
515 		return FALSE;
516 	}
517 #endif
518 
519 	for (p = fname; p != NULL; p = strchr(p, DIR_SEP)) {
520 		if ('.' == p[0] && '.' == p[1]
521 		    && ('\0' == p[2] || DIR_SEP == p[2]))
522 			return FALSE;
523 	}
524 
525 	return TRUE;
526 }
527 
528 
529 /*
530  * filegen registry
531  */
532 
533 static struct filegen_entry {
534 	char *			name;
535 	FILEGEN *		filegen;
536 	struct filegen_entry *	next;
537 } *filegen_registry = NULL;
538 
539 
540 FILEGEN *
541 filegen_get(
542 	const char *	name
543 	)
544 {
545 	struct filegen_entry *f = filegen_registry;
546 
547 	while (f) {
548 		if (f->name == name || strcmp(name, f->name) == 0) {
549 			DPRINTF(4, ("filegen_get(%s) = %p\n",
550 				    name, f->filegen));
551 			return f->filegen;
552 		}
553 		f = f->next;
554 	}
555 	DPRINTF(4, ("filegen_get(%s) = NULL\n", name));
556 	return NULL;
557 }
558 
559 
560 void
561 filegen_register(
562 	const char *	dir,
563 	const char *	name,
564 	FILEGEN *	filegen
565 	)
566 {
567 	struct filegen_entry **ppfe;
568 
569 	DPRINTF(4, ("filegen_register(%s, %p)\n", name, filegen));
570 
571 	filegen_init(dir, name, filegen);
572 
573 	ppfe = &filegen_registry;
574 	while (NULL != *ppfe) {
575 		if ((*ppfe)->name == name
576 		    || !strcmp((*ppfe)->name, name)) {
577 
578 			DPRINTF(5, ("replacing filegen %p\n",
579 				    (*ppfe)->filegen));
580 
581 			(*ppfe)->filegen = filegen;
582 			return;
583 		}
584 		ppfe = &((*ppfe)->next);
585 	}
586 
587 	*ppfe = emalloc(sizeof **ppfe);
588 
589 	(*ppfe)->next = NULL;
590 	(*ppfe)->name = estrdup(name);
591 	(*ppfe)->filegen = filegen;
592 
593 	DPRINTF(6, ("adding new filegen\n"));
594 
595 	return;
596 }
597 
598 
599 /*
600  * filegen_statsdir() - reset each filegen entry's dir to statsdir.
601  */
602 void
603 filegen_statsdir(void)
604 {
605 	struct filegen_entry *f;
606 
607 	for (f = filegen_registry; f != NULL; f = f->next)
608 		filegen_config(f->filegen, statsdir, f->filegen->fname,
609 			       f->filegen->type, f->filegen->flag);
610 }
611 
612 
613 /*
614  * filegen_unregister frees memory allocated by filegen_register for
615  * name.
616  */
617 #ifdef DEBUG
618 void
619 filegen_unregister(
620 	const char *name
621 	)
622 {
623 	struct filegen_entry **	ppfe;
624 	struct filegen_entry *	pfe;
625 	FILEGEN *		fg;
626 
627 	DPRINTF(4, ("filegen_unregister(%s)\n", name));
628 
629 	ppfe = &filegen_registry;
630 
631 	while (NULL != *ppfe) {
632 		if ((*ppfe)->name == name
633 		    || !strcmp((*ppfe)->name, name)) {
634 			pfe = *ppfe;
635 			*ppfe = (*ppfe)->next;
636 			fg = pfe->filegen;
637 			free(pfe->name);
638 			free(pfe);
639 			filegen_uninit(fg);
640 			break;
641 		}
642 		ppfe = &((*ppfe)->next);
643 	}
644 }
645 #endif	/* DEBUG */
646