usr.sbin/fifolog/lib/fifolog_reader.c

   1 /*-
   2  * Copyright (c) 2005-2008 Poul-Henning Kamp
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  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 *
  56 fifolog_reader_open(const char *fname)
  57 {
  58         const char *retval;
  59         struct fifolog_reader *fr;
  60         int i;
  61
  62         fr = calloc(sizeof *fr, 1);
  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->olen = fr->ff->recsize * 16;
  71         fr->obuf = calloc(fr->olen, 1);
  72         if (fr->obuf == NULL)
  73                 err(1, "Cannot malloc");
  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
  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
 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 *
 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
 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 }