usr.sbin/fifolog/lib/fifolog_reader.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   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  * $FreeBSD$
  29  */
  30
  31 #include <stdio.h>
  32 #include <unistd.h>
  33 #include <assert.h>
  34 #include <err.h>
  35 #include <time.h>
  36 #include <string.h>
  37 #include <stdlib.h>
  38 #include <zlib.h>
  39 #include <sys/endian.h>
  40
  41 #include "fifolog.h"
  42 #include "libfifolog.h"
  43 #include "libfifolog_int.h"
  44 #include "miniobj.h"
  45
  46 /*--------------------------------------------------------------------*/
  47
  48 struct fifolog_reader {
  49         unsigned                magic;
  50 #define FIFOLOG_READER_MAGIC    0x1036d139
  51         struct fifolog_file     *ff;
  52         unsigned                olen;
  53         unsigned char           *obuf;
  54         time_t                  now;
  55 };
  56
  57 struct fifolog_reader *
  58 fifolog_reader_open(const char *fname)
  59 {
  60         const char *retval;
  61         struct fifolog_reader *fr;
  62         int i;
  63
  64         fr = calloc(1, sizeof(*fr));
  65         if (fr == NULL)
  66                 err(1, "Cannot malloc");
  67
  68         retval = fifolog_int_open(&fr->ff, fname, 0);
  69         if (retval != NULL)
  70                 err(1, "%s", retval);
  71
  72         fr->obuf = calloc(16, fr->ff->recsize);
  73         if (fr->obuf == NULL)
  74                 err(1, "Cannot malloc");
  75         fr->olen = fr->ff->recsize * 16;
  76
  77         i = inflateInit(fr->ff->zs);
  78         assert(i == Z_OK);
  79
  80         fr->magic = FIFOLOG_READER_MAGIC;
  81         return (fr);
  82 }
  83
  84 /*
  85  * Find the next SYNC block
  86  *
  87  * Return:
  88  *      0 - empty fifolog
  89  *      1 - found sync block
  90  *      2 - would have wrapped around
  91  *      3 - End of written log.
  92  */
  93
  94 static int
  95 fifolog_reader_findsync(const struct fifolog_file *ff, off_t *o)
  96 {
  97         int e;
  98         unsigned seq, seqs;
  99
 100         assert(*o < ff->logsize);
 101         e = fifolog_int_read(ff, *o);
 102         if (e)
 103                 err(1, "Read error (%d) while looking for SYNC", e);
 104         seq = be32dec(ff->recbuf);
 105         if (*o == 0 && seq == 0)
 106                 return (0);
 107
 108         if (ff->recbuf[4] & FIFOLOG_FLG_SYNC)
 109                 return (1);             /* That was easy... */
 110         while(1) {
 111                 assert(*o < ff->logsize);
 112                 (*o)++;
 113                 seq++;
 114                 if (*o == ff->logsize)
 115                         return (2);     /* wraparound */
 116                 e = fifolog_int_read(ff, *o);
 117                 if (e)
 118                         err(1, "Read error (%d) while looking for SYNC", e);
 119                 seqs = be32dec(ff->recbuf);
 120                 if (seqs != seq)
 121                         return (3);             /* End of log */
 122                 if (ff->recbuf[4] & FIFOLOG_FLG_SYNC)
 123                         return (1);             /* Bingo! */
 124         }
 125 }
 126
 127 /*
 128  * Seek out a given timestamp
 129  */
 130
 131 off_t
 132 fifolog_reader_seek(const struct fifolog_reader *fr, time_t t0)
 133 {
 134         off_t o, s, st;
 135         time_t t, tt;
 136         unsigned seq, seqs;
 137         const char *retval;
 138         int e;
 139
 140         CHECK_OBJ_NOTNULL(fr, FIFOLOG_READER_MAGIC);
 141
 142         /*
 143          * First, find the first SYNC block
 144          */
 145         o = 0;
 146         e = fifolog_reader_findsync(fr->ff, &o);
 147         if (e == 0)
 148                 return (0);                     /* empty fifolog */
 149         assert(e == 1);
 150
 151         assert(fr->ff->recbuf[4] & FIFOLOG_FLG_SYNC);
 152         seq = be32dec(fr->ff->recbuf);
 153         t = be32dec(fr->ff->recbuf + 5);
 154
 155         if (t > t0) {
 156                 /* Check if there is a second older part we can use */
 157                 retval = fifolog_int_findend(fr->ff, &s);
 158                 if (retval != NULL)
 159                         err(1, "%s", retval);
 160                 s++;
 161                 e = fifolog_reader_findsync(fr->ff, &s);
 162                 if (e == 0)
 163                         return (0);             /* empty fifolog */
 164                 if (e == 1) {
 165                         o = s;
 166                         seq = be32dec(fr->ff->recbuf);
 167                         t = be32dec(fr->ff->recbuf + 5);
 168                 }
 169         }
 170
 171         /* Now do a binary search to find the sync block right before t0 */
 172         s = st = (fr->ff->logsize - o) / 2;
 173         while (s > 1) {
 174                 /* We know we shouldn't wrap */
 175                 if (o + st > fr->ff->logsize + 1) {
 176                         s = st = s / 2;
 177                         continue;
 178                 }
 179                 e = fifolog_int_read(fr->ff, o + st);
 180                 if (e) {
 181                         s = st = s / 2;
 182                         continue;
 183                 }
 184                 /* If not in same part, sequence won't match */
 185                 seqs = be32dec(fr->ff->recbuf);
 186                 if (seqs != seq + st) {
 187                         s = st = s / 2;
 188                         continue;
 189                 }
 190                 /* If not sync block, try next */
 191                 if (!(fr->ff->recbuf[4] & FIFOLOG_FLG_SYNC)) {
 192                         st++;
 193                         continue;
 194                 }
 195                 /* Check timestamp */
 196                 tt = be32dec(fr->ff->recbuf + 5);
 197                 if (tt >= t0) {
 198                         s = st = s / 2;
 199                         continue;
 200                 }
 201                 o += st;
 202                 seq = seqs;
 203         }
 204         fprintf(stderr, "Read from %jx\n", o * fr->ff->recsize);
 205         return (o);
 206 }
 207
 208 static unsigned char *
 209 fifolog_reader_chop(struct fifolog_reader *fr, fifolog_reader_render_t *func, void *priv)
 210 {
 211         u_char *p, *q;
 212         uint32_t v, w, u;
 213
 214         p = fr->obuf;
 215         q = fr->obuf + (fr->olen - fr->ff->zs->avail_out);
 216
 217         while (1) {
 218                 /* Make sure we have a complete header */
 219                 if (p + 5 >= q)
 220                         return (p);
 221                 w = 4;
 222                 u = be32dec(p);
 223                 if (u & FIFOLOG_TIMESTAMP) {
 224                         fr->now = be32dec(p + 4);
 225                         w += 4;
 226                 }
 227                 if (u & FIFOLOG_LENGTH) {
 228                         v = p[w];
 229                         w++;
 230                         if (p + w + v >= q)
 231                                 return (p);
 232                 } else {
 233                         for (v = 0; p + v + w < q && p[v + w] != '\0'; v++)
 234                                 continue;
 235                         if (p + v + w >= q)
 236                                 return (p);
 237                         v++;
 238                 }
 239                 func(priv, fr->now, u, p + w, v);
 240                 p += w + v;
 241         }
 242 }
 243
 244 /*
 245  * Process fifolog until end of written log or provided timestamp
 246  */
 247
 248 void
 249 fifolog_reader_process(struct fifolog_reader *fr, off_t from, fifolog_reader_render_t *func, void *priv, time_t end)
 250 {
 251         uint32_t seq, lseq;
 252         off_t o = from;
 253         int i, e;
 254         time_t t;
 255         u_char *p, *q;
 256         z_stream *zs;
 257
 258         CHECK_OBJ_NOTNULL(fr, FIFOLOG_READER_MAGIC);
 259         zs = fr->ff->zs;
 260         lseq = 0;
 261         while (1) {
 262                 e = fifolog_int_read(fr->ff, o);
 263                 if (e)
 264                         err(1, "Read error (%d)", e);
 265                 if (++o >= fr->ff->logsize)
 266                         o = 0;
 267                 seq = be32dec(fr->ff->recbuf);
 268                 if (lseq != 0 && seq != lseq + 1)
 269                         break;
 270                 lseq = seq;
 271                 zs->avail_in = fr->ff->recsize - 5;
 272                 zs->next_in = fr->ff->recbuf + 5;
 273                 if (fr->ff->recbuf[4] & FIFOLOG_FLG_1BYTE)
 274                         zs->avail_in -= fr->ff->recbuf[fr->ff->recsize - 1];
 275                 if (fr->ff->recbuf[4] & FIFOLOG_FLG_4BYTE)
 276                         zs->avail_in -=
 277                             be32dec(fr->ff->recbuf + fr->ff->recsize - 4);
 278                 if (fr->ff->recbuf[4] & FIFOLOG_FLG_SYNC) {
 279                         i = inflateReset(zs);
 280                         assert(i == Z_OK);
 281                         zs->next_out = fr->obuf;
 282                         zs->avail_out = fr->olen;
 283                         t = be32dec(fr->ff->recbuf + 5);
 284                         if (t > end)
 285                                 break;
 286                         zs->next_in += 4;
 287                         zs->avail_in -= 4;
 288                 }
 289
 290                 while(zs->avail_in > 0) {
 291                         i = inflate(zs, 0);
 292                         if (i == Z_BUF_ERROR) {
 293 #if 1
 294                                 fprintf(stderr,
 295                                     "Z_BUF_ERROR [%d,%d] [%d,%d,%d]\n",
 296                                     (int)(zs->next_in - fr->ff->recbuf),
 297                                     zs->avail_in,
 298                                     (int)(zs->next_out - fr->obuf),
 299                                     zs->avail_out, fr->olen);
 300                                 exit (250);
 301 #else
 302
 303                                 i = Z_OK;
 304 #endif
 305                         }
 306                         if (i == Z_STREAM_END) {
 307                                 i = inflateReset(zs);
 308                         }
 309                         if (i != Z_OK) {
 310                                 fprintf(stderr, "inflate = %d\n", i);
 311                                 exit (250);
 312                         }
 313                         assert(i == Z_OK);
 314                         if (zs->avail_out != fr->olen) {
 315                                 q = fr->obuf + (fr->olen - zs->avail_out);
 316                                 p = fifolog_reader_chop(fr, func, priv);
 317                                 if (p < q)
 318                                         (void)memmove(fr->obuf, p, q - p);
 319                                 zs->avail_out = fr->olen - (q - p);
 320                                 zs->next_out = fr->obuf + (q - p);
 321                         }
 322                 }
 323         }
 324 }