usr/src/boot/lib/libstand/gzipfs.c

   1 /*
   2  * Copyright (c) 1998 Michael Smith.
   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
  27 #include <sys/cdefs.h>
  28
  29 #include "stand.h"
  30
  31 #include <sys/stat.h>
  32 #include <string.h>
  33 #include <zlib.h>
  34
  35 #define Z_BUFSIZE 2048  /* XXX larger? */
  36
  37 struct z_file
  38 {
  39     int                 zf_rawfd;
  40     off_t               zf_dataoffset;
  41     z_stream            zf_zstream;
  42     unsigned char       zf_buf[Z_BUFSIZE];
  43     int                 zf_endseen;
  44 };
  45
  46 static int      zf_fill(struct z_file *z);
  47 static int      zf_open(const char *path, struct open_file *f);
  48 static int      zf_close(struct open_file *f);
  49 static int      zf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
  50 static off_t    zf_seek(struct open_file *f, off_t offset, int where);
  51 static int      zf_stat(struct open_file *f, struct stat *sb);
  52
  53 struct fs_ops gzipfs_fsops = {
  54     "zip",
  55     zf_open,
  56     zf_close,
  57     zf_read,
  58     null_write,
  59     zf_seek,
  60     zf_stat,
  61     null_readdir
  62 };
  63
  64 static int
  65 zf_fill(struct z_file *zf)
  66 {
  67     int         result;
  68     int         req;
  69
  70     req = Z_BUFSIZE - zf->zf_zstream.avail_in;
  71     result = 0;
  72
  73     /* If we need more */
  74     if (req > 0) {
  75         /* move old data to bottom of buffer */
  76         if (req < Z_BUFSIZE)
  77             bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req);
  78
  79         /* read to fill buffer and update availibility data */
  80         result = read(zf->zf_rawfd, zf->zf_buf + zf->zf_zstream.avail_in, req);
  81         zf->zf_zstream.next_in = zf->zf_buf;
  82         if (result >= 0)
  83             zf->zf_zstream.avail_in += result;
  84     }
  85     return(result);
  86 }
  87
  88 /*
  89  * Adapted from get_byte/check_header in libz
  90  *
  91  * Returns 0 if the header is OK, nonzero if not.
  92  */
  93 static int
  94 get_byte(struct z_file *zf, off_t *curoffp)
  95 {
  96     if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1))
  97         return(-1);
  98     zf->zf_zstream.avail_in--;
  99     ++*curoffp;
 100     return(*(zf->zf_zstream.next_in)++);
 101 }
 102
 103 static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
 104
 105 /* gzip flag byte */
 106 #define ASCII_FLAG      0x01 /* bit 0 set: file probably ascii text */
 107 #define HEAD_CRC        0x02 /* bit 1 set: header CRC present */
 108 #define EXTRA_FIELD     0x04 /* bit 2 set: extra field present */
 109 #define ORIG_NAME       0x08 /* bit 3 set: original file name present */
 110 #define COMMENT         0x10 /* bit 4 set: file comment present */
 111 #define RESERVED        0xE0 /* bits 5..7: reserved */
 112
 113 static int
 114 check_header(struct z_file *zf)
 115 {
 116     int         method; /* method byte */
 117     int         flags;  /* flags byte */
 118     uInt        len;
 119     int         c;
 120
 121     zf->zf_dataoffset = 0;
 122     /* Check the gzip magic header */
 123     for (len = 0; len < 2; len++) {
 124         c = get_byte(zf, &zf->zf_dataoffset);
 125         if (c != gz_magic[len]) {
 126             return(1);
 127         }
 128     }
 129     method = get_byte(zf, &zf->zf_dataoffset);
 130     flags = get_byte(zf, &zf->zf_dataoffset);
 131     if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
 132         return(1);
 133     }
 134
 135     /* Discard time, xflags and OS code: */
 136     for (len = 0; len < 6; len++) (void)get_byte(zf, &zf->zf_dataoffset);
 137
 138     if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
 139         len  =  (uInt)get_byte(zf, &zf->zf_dataoffset);
 140         len += ((uInt)get_byte(zf, &zf->zf_dataoffset))<<8;
 141         /* len is garbage if EOF but the loop below will quit anyway */
 142         while (len-- != 0 && get_byte(zf, &zf->zf_dataoffset) != -1) ;
 143     }
 144     if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
 145         while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ;
 146     }
 147     if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
 148         while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ;
 149     }
 150     if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
 151         for (len = 0; len < 2; len++) c = get_byte(zf, &zf->zf_dataoffset);
 152     }
 153     /* if there's data left, we're in business */
 154     return((c == -1) ? 1 : 0);
 155 }
 156
 157 static int
 158 zf_open(const char *fname, struct open_file *f)
 159 {
 160     char                *zfname;
 161     int                 rawfd;
 162     struct z_file       *zf;
 163     char                *cp;
 164     int                 error;
 165     struct stat         sb;
 166
 167     /* Have to be in "just read it" mode */
 168     if (f->f_flags != F_READ)
 169         return(EPERM);
 170
 171     /* If the name already ends in .gz or .bz2, ignore it */
 172     if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
 173             || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
 174         return(ENOENT);
 175
 176     /* Try to open the compressed datafile */
 177     rawfd = open(fname, O_RDONLY | F_GZIP);
 178     if (rawfd == -1) {
 179         /* add .gz sufix and try again */
 180         zfname = malloc(strlen(fname) + 4);
 181         if (zfname == NULL)
 182                 return(ENOMEM);
 183         sprintf(zfname, "%s.gz", fname);
 184         rawfd = open(zfname, O_RDONLY);
 185         free(zfname);
 186         if (rawfd == -1)
 187                 return(ENOENT);
 188     }
 189
 190     if (fstat(rawfd, &sb) < 0) {
 191         printf("zf_open: stat failed\n");
 192         close(rawfd);
 193         return(ENOENT);
 194     }
 195     if (!S_ISREG(sb.st_mode)) {
 196         close(rawfd);
 197         return(EISDIR);                 /* best guess */
 198     }
 199
 200     /* Allocate a z_file structure, populate it */
 201     zf = malloc(sizeof(struct z_file));
 202     if (zf == NULL)
 203         return(ENOMEM);
 204     bzero(zf, sizeof(struct z_file));
 205     zf->zf_rawfd = rawfd;
 206
 207     /* Verify that the file is gzipped */
 208     if (check_header(zf)) {
 209         close(zf->zf_rawfd);
 210         free(zf);
 211         return(EFTYPE);
 212     }
 213
 214     /* Initialise the inflation engine */
 215     if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) {
 216         printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg);
 217         close(zf->zf_rawfd);
 218         free(zf);
 219         return(EIO);
 220     }
 221
 222     /* Looks OK, we'll take it */
 223     f->f_fsdata = zf;
 224     return(0);
 225 }
 226
 227 static int
 228 zf_close(struct open_file *f)
 229 {
 230     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 231
 232     inflateEnd(&(zf->zf_zstream));
 233     close(zf->zf_rawfd);
 234     free(zf);
 235     return(0);
 236 }
 237
 238 static int
 239 zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
 240 {
 241     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 242     int                 error;
 243
 244     zf->zf_zstream.next_out = buf;                      /* where and how much */
 245     zf->zf_zstream.avail_out = size;
 246
 247     while (zf->zf_zstream.avail_out && zf->zf_endseen == 0) {
 248         if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
 249             printf("zf_read: fill error\n");
 250             return(EIO);
 251         }
 252         if (zf->zf_zstream.avail_in == 0) {             /* oops, unexpected EOF */
 253             printf("zf_read: unexpected EOF\n");
 254             if (zf->zf_zstream.avail_out == size)
 255                 return(EIO);
 256             break;
 257         }
 258
 259         error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */
 260         if (error == Z_STREAM_END) {                    /* EOF, all done */
 261             zf->zf_endseen = 1;
 262             break;
 263         }
 264         if (error != Z_OK) {                            /* argh, decompression error */
 265             printf("inflate: %s\n", zf->zf_zstream.msg);
 266             return(EIO);
 267         }
 268     }
 269     if (resid != NULL)
 270         *resid = zf->zf_zstream.avail_out;
 271     return(0);
 272 }
 273
 274 static int
 275 zf_rewind(struct open_file *f)
 276 {
 277     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 278
 279     if (lseek(zf->zf_rawfd, zf->zf_dataoffset, SEEK_SET) == -1)
 280         return(-1);
 281     zf->zf_zstream.avail_in = 0;
 282     zf->zf_zstream.next_in = NULL;
 283     zf->zf_endseen = 0;
 284     (void)inflateReset(&zf->zf_zstream);
 285
 286     return(0);
 287 }
 288
 289 static off_t
 290 zf_seek(struct open_file *f, off_t offset, int where)
 291 {
 292     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 293     off_t               target;
 294     char                discard[16];
 295
 296     switch (where) {
 297     case SEEK_SET:
 298         target = offset;
 299         break;
 300     case SEEK_CUR:
 301         target = offset + zf->zf_zstream.total_out;
 302         break;
 303     default:
 304         errno = EINVAL;
 305         return(-1);
 306     }
 307
 308     /* rewind if required */
 309     if (target < zf->zf_zstream.total_out && zf_rewind(f) != 0)
 310         return(-1);
 311
 312     /* skip forwards if required */
 313     while (target > zf->zf_zstream.total_out) {
 314         errno = zf_read(f, discard, min(sizeof(discard),
 315             target - zf->zf_zstream.total_out), NULL);
 316         if (errno)
 317             return(-1);
 318     }
 319     /* This is where we are (be honest if we overshot) */
 320     return(zf->zf_zstream.total_out);
 321 }
 322
 323
 324 static int
 325 zf_stat(struct open_file *f, struct stat *sb)
 326 {
 327     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 328     int                 result, res;
 329     off_t               pos1, pos2;
 330     uint32_t            size;
 331
 332     /* stat as normal, but indicate that size is unknown */
 333     if ((result = fstat(zf->zf_rawfd, sb)) == 0) {
 334         if (sb->st_size == -1)
 335             return (result);
 336         pos1 = lseek(zf->zf_rawfd, 0, SEEK_CUR);
 337         pos2 = lseek(zf->zf_rawfd, sb->st_size - 4, SEEK_SET);
 338         if (pos2 != -1) {
 339             if (read(zf->zf_rawfd, &size, 4) == 4)
 340                 sb->st_size = (off_t) size;
 341             else
 342                 sb->st_size = -1;
 343         } else
 344             sb->st_size = -1;
 345
 346         pos1 = lseek(zf->zf_rawfd, pos1, SEEK_SET);
 347     }
 348     return(result);
 349 }