xref: /freebsd/usr.sbin/fifolog/lib/fifolog_reader.c (revision b3e7694832e81d7a904a10f525f8797b753bf0d3)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2005-2008 Poul-Henning Kamp
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <stdio.h>
30 #include <unistd.h>
31 #include <assert.h>
32 #include <err.h>
33 #include <time.h>
34 #include <string.h>
35 #include <stdlib.h>
36 #include <zlib.h>
37 #include <sys/endian.h>
38 
39 #include "fifolog.h"
40 #include "libfifolog.h"
41 #include "libfifolog_int.h"
42 #include "miniobj.h"
43 
44 /*--------------------------------------------------------------------*/
45 
46 struct fifolog_reader {
47 	unsigned		magic;
48 #define FIFOLOG_READER_MAGIC	0x1036d139
49 	struct fifolog_file	*ff;
50 	unsigned		olen;
51 	unsigned char		*obuf;
52 	time_t			now;
53 };
54 
55 struct fifolog_reader *
fifolog_reader_open(const char * fname)56 fifolog_reader_open(const char *fname)
57 {
58 	const char *retval;
59 	struct fifolog_reader *fr;
60 	int i;
61 
62 	fr = calloc(1, sizeof(*fr));
63 	if (fr == NULL)
64 		err(1, "Cannot malloc");
65 
66 	retval = fifolog_int_open(&fr->ff, fname, 0);
67 	if (retval != NULL)
68 		err(1, "%s", retval);
69 
70 	fr->obuf = calloc(16, fr->ff->recsize);
71 	if (fr->obuf == NULL)
72 		err(1, "Cannot malloc");
73 	fr->olen = fr->ff->recsize * 16;
74 
75 	i = inflateInit(fr->ff->zs);
76 	assert(i == Z_OK);
77 
78 	fr->magic = FIFOLOG_READER_MAGIC;
79 	return (fr);
80 }
81 
82 /*
83  * Find the next SYNC block
84  *
85  * Return:
86  *	0 - empty fifolog
87  *	1 - found sync block
88  *	2 - would have wrapped around
89  *	3 - End of written log.
90  */
91 
92 static int
fifolog_reader_findsync(const struct fifolog_file * ff,off_t * o)93 fifolog_reader_findsync(const struct fifolog_file *ff, off_t *o)
94 {
95 	int e;
96 	unsigned seq, seqs;
97 
98 	assert(*o < ff->logsize);
99 	e = fifolog_int_read(ff, *o);
100 	if (e)
101 		err(1, "Read error (%d) while looking for SYNC", e);
102 	seq = be32dec(ff->recbuf);
103 	if (*o == 0 && seq == 0)
104 		return (0);
105 
106 	if (ff->recbuf[4] & FIFOLOG_FLG_SYNC)
107 		return (1);		/* That was easy... */
108 	while(1) {
109 		assert(*o < ff->logsize);
110 		(*o)++;
111 		seq++;
112 		if (*o == ff->logsize)
113 			return (2);	/* wraparound */
114 		e = fifolog_int_read(ff, *o);
115 		if (e)
116 			err(1, "Read error (%d) while looking for SYNC", e);
117 		seqs = be32dec(ff->recbuf);
118 		if (seqs != seq)
119 			return (3);		/* End of log */
120 		if (ff->recbuf[4] & FIFOLOG_FLG_SYNC)
121 			return (1);		/* Bingo! */
122 	}
123 }
124 
125 /*
126  * Seek out a given timestamp
127  */
128 
129 off_t
fifolog_reader_seek(const struct fifolog_reader * fr,time_t t0)130 fifolog_reader_seek(const struct fifolog_reader *fr, time_t t0)
131 {
132 	off_t o, s, st;
133 	time_t t, tt;
134 	unsigned seq, seqs;
135 	const char *retval;
136 	int e;
137 
138 	CHECK_OBJ_NOTNULL(fr, FIFOLOG_READER_MAGIC);
139 
140 	/*
141 	 * First, find the first SYNC block
142 	 */
143 	o = 0;
144 	e = fifolog_reader_findsync(fr->ff, &o);
145 	if (e == 0)
146 		return (0);			/* empty fifolog */
147 	assert(e == 1);
148 
149 	assert(fr->ff->recbuf[4] & FIFOLOG_FLG_SYNC);
150 	seq = be32dec(fr->ff->recbuf);
151 	t = be32dec(fr->ff->recbuf + 5);
152 
153 	if (t > t0) {
154 		/* Check if there is a second older part we can use */
155 		retval = fifolog_int_findend(fr->ff, &s);
156 		if (retval != NULL)
157 			err(1, "%s", retval);
158 		s++;
159 		e = fifolog_reader_findsync(fr->ff, &s);
160 		if (e == 0)
161 			return (0);		/* empty fifolog */
162 		if (e == 1) {
163 			o = s;
164 			seq = be32dec(fr->ff->recbuf);
165 			t = be32dec(fr->ff->recbuf + 5);
166 		}
167 	}
168 
169 	/* Now do a binary search to find the sync block right before t0 */
170 	s = st = (fr->ff->logsize - o) / 2;
171 	while (s > 1) {
172 		/* We know we shouldn't wrap */
173 		if (o + st > fr->ff->logsize + 1) {
174 			s = st = s / 2;
175 			continue;
176 		}
177 		e = fifolog_int_read(fr->ff, o + st);
178 		if (e) {
179 			s = st = s / 2;
180 			continue;
181 		}
182 		/* If not in same part, sequence won't match */
183 		seqs = be32dec(fr->ff->recbuf);
184 		if (seqs != seq + st) {
185 			s = st = s / 2;
186 			continue;
187 		}
188 		/* If not sync block, try next */
189 		if (!(fr->ff->recbuf[4] & FIFOLOG_FLG_SYNC)) {
190 			st++;
191 			continue;
192 		}
193 		/* Check timestamp */
194 		tt = be32dec(fr->ff->recbuf + 5);
195 		if (tt >= t0) {
196 			s = st = s / 2;
197 			continue;
198 		}
199 		o += st;
200 		seq = seqs;
201 	}
202 	fprintf(stderr, "Read from %jx\n", o * fr->ff->recsize);
203 	return (o);
204 }
205 
206 static unsigned char *
fifolog_reader_chop(struct fifolog_reader * fr,fifolog_reader_render_t * func,void * priv)207 fifolog_reader_chop(struct fifolog_reader *fr, fifolog_reader_render_t *func, void *priv)
208 {
209 	u_char *p, *q;
210 	uint32_t v, w, u;
211 
212 	p = fr->obuf;
213 	q = fr->obuf + (fr->olen - fr->ff->zs->avail_out);
214 
215 	while (1) {
216 		/* Make sure we have a complete header */
217 		if (p + 5 >= q)
218 			return (p);
219 		w = 4;
220 		u = be32dec(p);
221 		if (u & FIFOLOG_TIMESTAMP) {
222 			fr->now = be32dec(p + 4);
223 			w += 4;
224 		}
225 		if (u & FIFOLOG_LENGTH) {
226 			v = p[w];
227 			w++;
228 			if (p + w + v >= q)
229 				return (p);
230 		} else {
231 			for (v = 0; p + v + w < q && p[v + w] != '\0'; v++)
232 				continue;
233 			if (p + v + w >= q)
234 				return (p);
235 			v++;
236 		}
237 		func(priv, fr->now, u, p + w, v);
238 		p += w + v;
239 	}
240 }
241 
242 /*
243  * Process fifolog until end of written log or provided timestamp
244  */
245 
246 void
fifolog_reader_process(struct fifolog_reader * fr,off_t from,fifolog_reader_render_t * func,void * priv,time_t end)247 fifolog_reader_process(struct fifolog_reader *fr, off_t from, fifolog_reader_render_t *func, void *priv, time_t end)
248 {
249 	uint32_t seq, lseq;
250 	off_t o = from;
251 	int i, e;
252 	time_t t;
253 	u_char *p, *q;
254 	z_stream *zs;
255 
256 	CHECK_OBJ_NOTNULL(fr, FIFOLOG_READER_MAGIC);
257 	zs = fr->ff->zs;
258 	lseq = 0;
259 	while (1) {
260 		e = fifolog_int_read(fr->ff, o);
261 		if (e)
262 			err(1, "Read error (%d)", e);
263 		if (++o >= fr->ff->logsize)
264 			o = 0;
265 		seq = be32dec(fr->ff->recbuf);
266 		if (lseq != 0 && seq != lseq + 1)
267 			break;
268 		lseq = seq;
269 		zs->avail_in = fr->ff->recsize - 5;
270 		zs->next_in = fr->ff->recbuf + 5;
271 		if (fr->ff->recbuf[4] & FIFOLOG_FLG_1BYTE)
272 			zs->avail_in -= fr->ff->recbuf[fr->ff->recsize - 1];
273 		if (fr->ff->recbuf[4] & FIFOLOG_FLG_4BYTE)
274 			zs->avail_in -=
275 			    be32dec(fr->ff->recbuf + fr->ff->recsize - 4);
276 		if (fr->ff->recbuf[4] & FIFOLOG_FLG_SYNC) {
277 			i = inflateReset(zs);
278 			assert(i == Z_OK);
279 			zs->next_out = fr->obuf;
280 			zs->avail_out = fr->olen;
281 			t = be32dec(fr->ff->recbuf + 5);
282 			if (t > end)
283 				break;
284 			zs->next_in += 4;
285 			zs->avail_in -= 4;
286 		}
287 
288 		while(zs->avail_in > 0) {
289 			i = inflate(zs, 0);
290 			if (i == Z_BUF_ERROR) {
291 #if 1
292 				fprintf(stderr,
293 				    "Z_BUF_ERROR [%d,%d] [%d,%d,%d]\n",
294 				    (int)(zs->next_in - fr->ff->recbuf),
295 				    zs->avail_in,
296 				    (int)(zs->next_out - fr->obuf),
297 				    zs->avail_out, fr->olen);
298 				exit (250);
299 #else
300 
301 				i = Z_OK;
302 #endif
303 			}
304 			if (i == Z_STREAM_END) {
305 				i = inflateReset(zs);
306 			}
307 			if (i != Z_OK) {
308 				fprintf(stderr, "inflate = %d\n", i);
309 				exit (250);
310 			}
311 			assert(i == Z_OK);
312 			if (zs->avail_out != fr->olen) {
313 				q = fr->obuf + (fr->olen - zs->avail_out);
314 				p = fifolog_reader_chop(fr, func, priv);
315 				if (p < q)
316 					(void)memmove(fr->obuf, p, q - p);
317 				zs->avail_out = fr->olen - (q - p);
318 				zs->next_out = fr->obuf + (q - p);
319 			}
320 		}
321 	}
322 }
323