lib/libstand/bzipfs.c

   1 /*
   2  * Copyright (c) 1998 Michael Smith.
   3  * Copyright (c) 2000 Maxim Sobolev
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  * $FreeBSD: src/lib/libstand/bzipfs.c,v 1.2.2.3 2002/04/08 13:50:09 sobomax Exp $
  28  * $DragonFly: src/lib/libstand/bzipfs.c,v 1.4 2007/05/13 18:33:56 swildner Exp $
  29  *
  30  */
  31
  32 #include "stand.h"
  33
  34 #include <sys/stat.h>
  35 #include <string.h>
  36 #include <bzlib.h>
  37
  38 #define BZ_BUFSIZE 2048 /* XXX larger? */
  39
  40 struct bz_file
  41 {
  42     int                 bzf_rawfd;
  43     bz_stream           bzf_bzstream;
  44     char                bzf_buf[BZ_BUFSIZE];
  45 };
  46
  47 static int      bzf_fill(struct bz_file *z);
  48 static int      bzf_open(const char *path, struct open_file *f);
  49 static int      bzf_close(struct open_file *f);
  50 static int      bzf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
  51 static off_t    bzf_seek(struct open_file *f, off_t offset, int where);
  52 static int      bzf_stat(struct open_file *f, struct stat *sb);
  53
  54 struct fs_ops bzipfs_fsops = {
  55     "bzip",
  56     bzf_open,
  57     bzf_close,
  58     bzf_read,
  59     null_write,
  60     bzf_seek,
  61     bzf_stat,
  62     null_readdir
  63 };
  64
  65 #if 0
  66 void *
  67 calloc(int items, size_t size)
  68 {
  69     return(malloc(items * size));
  70 }
  71 #endif
  72
  73 static int
  74 bzf_fill(struct bz_file *bzf)
  75 {
  76     int         result;
  77     int         req;
  78
  79     req = BZ_BUFSIZE - bzf->bzf_bzstream.avail_in;
  80     result = 0;
  81
  82     /* If we need more */
  83     if (req > 0) {
  84         /* move old data to bottom of buffer */
  85         if (req < BZ_BUFSIZE)
  86             bcopy(bzf->bzf_buf + req, bzf->bzf_buf, BZ_BUFSIZE - req);
  87
  88         /* read to fill buffer and update availibility data */
  89         result = read(bzf->bzf_rawfd, bzf->bzf_buf + bzf->bzf_bzstream.avail_in, req);
  90         bzf->bzf_bzstream.next_in = bzf->bzf_buf;
  91         if (result >= 0)
  92             bzf->bzf_bzstream.avail_in += result;
  93     }
  94     return(result);
  95 }
  96
  97 /*
  98  * Adapted from get_byte/check_header in libz
  99  *
 100  * Returns 0 if the header is OK, nonzero if not.
 101  */
 102 static int
 103 get_byte(struct bz_file *bzf)
 104 {
 105     if ((bzf->bzf_bzstream.avail_in == 0) && (bzf_fill(bzf) == -1))
 106         return(-1);
 107     bzf->bzf_bzstream.avail_in--;
 108     return(*(bzf->bzf_bzstream.next_in)++);
 109 }
 110
 111 static int bz_magic[3] = {'B', 'Z', 'h'}; /* bzip2 magic header */
 112
 113 static int
 114 check_header(struct bz_file *bzf)
 115 {
 116     unsigned int len;
 117     int          c;
 118
 119     /* Check the bzip2 magic header */
 120     for (len = 0; len < 3; len++) {
 121         c = get_byte(bzf);
 122         if (c != bz_magic[len]) {
 123             return(1);
 124         }
 125     }
 126     /* Check that the block size is valid */
 127     c = get_byte(bzf);
 128     if (c < '1' || c > '9')
 129         return(1);
 130
 131     /* Put back bytes that we've took from the input stream */
 132     bzf->bzf_bzstream.next_in -= 4;
 133     bzf->bzf_bzstream.avail_in += 4;
 134
 135     return(0);
 136 }
 137
 138 static int
 139 bzf_open(const char *fname, struct open_file *f)
 140 {
 141     static char         *bzfname;
 142     int                 rawfd;
 143     struct bz_file      *bzf;
 144     char                *cp;
 145     int                 error;
 146     struct stat         sb;
 147
 148     /* Have to be in "just read it" mode */
 149     if (f->f_flags != F_READ)
 150         return(EPERM);
 151
 152     /* If the name already ends in .gz or .bz2, ignore it */
 153     if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
 154             || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
 155         return(ENOENT);
 156
 157     /* Construct new name */
 158     bzfname = malloc(strlen(fname) + 5);
 159     sprintf(bzfname, "%s.bz2", fname);
 160
 161     /* Try to open the compressed datafile */
 162     rawfd = open(bzfname, O_RDONLY);
 163     free(bzfname);
 164     if (rawfd == -1)
 165         return(ENOENT);
 166
 167     if (fstat(rawfd, &sb) < 0) {
 168         printf("bzf_open: stat failed\n");
 169         close(rawfd);
 170         return(ENOENT);
 171     }
 172     if (!S_ISREG(sb.st_mode)) {
 173         printf("bzf_open: not a file\n");
 174         close(rawfd);
 175         return(EISDIR);                 /* best guess */
 176     }
 177
 178     /* Allocate a bz_file structure, populate it */
 179     bzf = malloc(sizeof(struct bz_file));
 180     bzero(bzf, sizeof(struct bz_file));
 181     bzf->bzf_rawfd = rawfd;
 182
 183     /* Verify that the file is bzipped (XXX why do this afterwards?) */
 184     if (check_header(bzf)) {
 185         close(bzf->bzf_rawfd);
 186         BZ2_bzDecompressEnd(&(bzf->bzf_bzstream));
 187         free(bzf);
 188         return(EFTYPE);
 189     }
 190
 191     /* Initialise the inflation engine */
 192     if ((error = BZ2_bzDecompressInit(&(bzf->bzf_bzstream), 0, 1)) != BZ_OK) {
 193         printf("bzf_open: BZ2_bzDecompressInit returned %d\n", error);
 194         close(bzf->bzf_rawfd);
 195         free(bzf);
 196         return(EIO);
 197     }
 198
 199     /* Looks OK, we'll take it */
 200     f->f_fsdata = bzf;
 201     return(0);
 202 }
 203
 204 static int
 205 bzf_close(struct open_file *f)
 206 {
 207     struct bz_file      *bzf = (struct bz_file *)f->f_fsdata;
 208
 209     f->f_fsdata = NULL;
 210     if (bzf) {
 211         BZ2_bzDecompressEnd(&(bzf->bzf_bzstream));
 212         close(bzf->bzf_rawfd);
 213         free(bzf);
 214     }
 215     return(0);
 216 }
 217
 218 static int
 219 bzf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
 220 {
 221     struct bz_file      *bzf = (struct bz_file *)f->f_fsdata;
 222     int                 error;
 223
 224     bzf->bzf_bzstream.next_out = buf;                   /* where and how much */
 225     bzf->bzf_bzstream.avail_out = size;
 226
 227     while (bzf->bzf_bzstream.avail_out) {
 228         if ((bzf->bzf_bzstream.avail_in == 0) && (bzf_fill(bzf) == -1)) {
 229             printf("bzf_read: fill error\n");
 230             return(-1);
 231         }
 232         if (bzf->bzf_bzstream.avail_in == 0) {          /* oops, unexpected EOF */
 233             printf("bzf_read: unexpected EOF\n");
 234             break;
 235         }
 236
 237         error = BZ2_bzDecompress(&bzf->bzf_bzstream);   /* decompression pass */
 238         if (error == BZ_STREAM_END) {                   /* EOF, all done */
 239             break;
 240         }
 241         if (error != BZ_OK) {                           /* argh, decompression error */
 242             printf("bzf_read: BZ2_bzDecompress returned %d\n", error);
 243             errno = EIO;
 244             return(-1);
 245         }
 246     }
 247     if (resid != NULL)
 248         *resid = bzf->bzf_bzstream.avail_out;
 249     return(0);
 250 }
 251
 252 static off_t
 253 bzf_seek(struct open_file *f, off_t offset, int where)
 254 {
 255     struct bz_file      *bzf = (struct bz_file *)f->f_fsdata;
 256     off_t               target;
 257     char                discard[16];
 258
 259     switch (where) {
 260     case SEEK_SET:
 261         target = offset;
 262         break;
 263     case SEEK_CUR:
 264         target = offset + bzf->bzf_bzstream.total_out_lo32;
 265         break;
 266     default:
 267         target = -1;
 268     }
 269
 270     /* Can we get there from here? */
 271     if (target < bzf->bzf_bzstream.total_out_lo32) {
 272         errno = EOFFSET;
 273         return -1;
 274     }
 275
 276     /* skip forwards if required */
 277     while (target > bzf->bzf_bzstream.total_out_lo32) {
 278         if (bzf_read(f, discard, min(sizeof(discard), target - bzf->bzf_bzstream.total_out_lo32), NULL) == -1)
 279             return(-1);
 280     }
 281     /* This is where we are (be honest if we overshot) */
 282     return (bzf->bzf_bzstream.total_out_lo32);
 283 }
 284
 285 static int
 286 bzf_stat(struct open_file *f, struct stat *sb)
 287 {
 288     struct bz_file      *bzf = (struct bz_file *)f->f_fsdata;
 289     int                 result;
 290
 291     /* stat as normal, but indicate that size is unknown */
 292     if ((result = fstat(bzf->bzf_rawfd, sb)) == 0)
 293         sb->st_size = -1;
 294     return(result);
 295 }
 296
 297 void
 298 bz_internal_error(int errorcode)
 299 {
 300     panic("bzipfs: critical error %d in bzip2 library occurred\n", errorcode);
 301 }