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 __FBSDID("$FreeBSD$");
  29
  30 #include "stand.h"
  31
  32 #include <sys/stat.h>
  33 #include <string.h>
  34 #include <zlib.h>
  35
  36 #define Z_BUFSIZE 2048  /* XXX larger? */
  37
  38 struct z_file
  39 {
  40     int                 zf_rawfd;
  41     off_t               zf_dataoffset;
  42     z_stream            zf_zstream;
  43     char                zf_buf[Z_BUFSIZE];
  44     int                 zf_endseen;
  45 };
  46
  47 static int      zf_fill(struct z_file *z);
  48 static int      zf_open(const char *path, struct open_file *f);
  49 static int      zf_close(struct open_file *f);
  50 static int      zf_read(struct open_file *f, void *buf, size_t size, size_t *resid);
  51 static off_t    zf_seek(struct open_file *f, off_t offset, int where);
  52 static int      zf_stat(struct open_file *f, struct stat *sb);
  53
  54 struct fs_ops gzipfs_fsops = {
  55     "zip",
  56     zf_open,
  57     zf_close,
  58     zf_read,
  59     null_write,
  60     zf_seek,
  61     zf_stat,
  62     null_readdir
  63 };
  64
  65 static int
  66 zf_fill(struct z_file *zf)
  67 {
  68     int         result;
  69     int         req;
  70
  71     req = Z_BUFSIZE - zf->zf_zstream.avail_in;
  72     result = 0;
  73
  74     /* If we need more */
  75     if (req > 0) {
  76         /* move old data to bottom of buffer */
  77         if (req < Z_BUFSIZE)
  78             bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req);
  79
  80         /* read to fill buffer and update availibility data */
  81         result = read(zf->zf_rawfd, zf->zf_buf + zf->zf_zstream.avail_in, req);
  82         zf->zf_zstream.next_in = zf->zf_buf;
  83         if (result >= 0)
  84             zf->zf_zstream.avail_in += result;
  85     }
  86     return(result);
  87 }
  88
  89 /*
  90  * Adapted from get_byte/check_header in libz
  91  *
  92  * Returns 0 if the header is OK, nonzero if not.
  93  */
  94 static int
  95 get_byte(struct z_file *zf, off_t *curoffp)
  96 {
  97     if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1))
  98         return(-1);
  99     zf->zf_zstream.avail_in--;
 100     ++*curoffp;
 101     return(*(zf->zf_zstream.next_in)++);
 102 }
 103
 104 static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
 105
 106 /* gzip flag byte */
 107 #define ASCII_FLAG      0x01 /* bit 0 set: file probably ascii text */
 108 #define HEAD_CRC        0x02 /* bit 1 set: header CRC present */
 109 #define EXTRA_FIELD     0x04 /* bit 2 set: extra field present */
 110 #define ORIG_NAME       0x08 /* bit 3 set: original file name present */
 111 #define COMMENT         0x10 /* bit 4 set: file comment present */
 112 #define RESERVED        0xE0 /* bits 5..7: reserved */
 113
 114 static int
 115 check_header(struct z_file *zf)
 116 {
 117     int         method; /* method byte */
 118     int         flags;  /* flags byte */
 119     uInt        len;
 120     int         c;
 121
 122     zf->zf_dataoffset = 0;
 123     /* Check the gzip magic header */
 124     for (len = 0; len < 2; len++) {
 125         c = get_byte(zf, &zf->zf_dataoffset);
 126         if (c != gz_magic[len]) {
 127             return(1);
 128         }
 129     }
 130     method = get_byte(zf, &zf->zf_dataoffset);
 131     flags = get_byte(zf, &zf->zf_dataoffset);
 132     if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
 133         return(1);
 134     }
 135
 136     /* Discard time, xflags and OS code: */
 137     for (len = 0; len < 6; len++) (void)get_byte(zf, &zf->zf_dataoffset);
 138
 139     if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
 140         len  =  (uInt)get_byte(zf, &zf->zf_dataoffset);
 141         len += ((uInt)get_byte(zf, &zf->zf_dataoffset))<<8;
 142         /* len is garbage if EOF but the loop below will quit anyway */
 143         while (len-- != 0 && get_byte(zf, &zf->zf_dataoffset) != -1) ;
 144     }
 145     if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
 146         while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ;
 147     }
 148     if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
 149         while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1) ;
 150     }
 151     if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
 152         for (len = 0; len < 2; len++) c = get_byte(zf, &zf->zf_dataoffset);
 153     }
 154     /* if there's data left, we're in business */
 155     return((c == -1) ? 1 : 0);
 156 }
 157
 158 static int
 159 zf_open(const char *fname, struct open_file *f)
 160 {
 161     char                *zfname;
 162     int                 rawfd;
 163     struct z_file       *zf;
 164     char                *cp;
 165     int                 error;
 166     struct stat         sb;
 167
 168     /* Have to be in "just read it" mode */
 169     if (f->f_flags != F_READ)
 170         return(EPERM);
 171
 172     /* If the name already ends in .gz or .bz2, ignore it */
 173     if ((cp = strrchr(fname, '.')) && (!strcmp(cp, ".gz")
 174             || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
 175         return(ENOENT);
 176
 177     /* Try to open the compressed datafile */
 178     rawfd = open(fname, O_RDONLY | F_GZIP);
 179     if (rawfd == -1) {
 180         /* add .gz sufix and try again */
 181         zfname = malloc(strlen(fname) + 4);
 182         if (zfname == NULL)
 183                 return(ENOMEM);
 184         sprintf(zfname, "%s.gz", fname);
 185         rawfd = open(zfname, O_RDONLY);
 186         free(zfname);
 187         if (rawfd == -1)
 188                 return(ENOENT);
 189     }
 190
 191     if (fstat(rawfd, &sb) < 0) {
 192         printf("zf_open: stat failed\n");
 193         close(rawfd);
 194         return(ENOENT);
 195     }
 196     if (!S_ISREG(sb.st_mode)) {
 197         close(rawfd);
 198         return(EISDIR);                 /* best guess */
 199     }
 200
 201     /* Allocate a z_file structure, populate it */
 202     zf = malloc(sizeof(struct z_file));
 203     if (zf == NULL)
 204         return(ENOMEM);
 205     bzero(zf, sizeof(struct z_file));
 206     zf->zf_rawfd = rawfd;
 207
 208     /* Verify that the file is gzipped */
 209     if (check_header(zf)) {
 210         close(zf->zf_rawfd);
 211         free(zf);
 212         return(EFTYPE);
 213     }
 214
 215     /* Initialise the inflation engine */
 216     if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) {
 217         printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg);
 218         close(zf->zf_rawfd);
 219         free(zf);
 220         return(EIO);
 221     }
 222
 223     /* Looks OK, we'll take it */
 224     f->f_fsdata = zf;
 225     return(0);
 226 }
 227
 228 static int
 229 zf_close(struct open_file *f)
 230 {
 231     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 232
 233     inflateEnd(&(zf->zf_zstream));
 234     close(zf->zf_rawfd);
 235     free(zf);
 236     return(0);
 237 }
 238
 239 static int
 240 zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
 241 {
 242     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 243     int                 error;
 244
 245     zf->zf_zstream.next_out = buf;                      /* where and how much */
 246     zf->zf_zstream.avail_out = size;
 247
 248     while (zf->zf_zstream.avail_out && zf->zf_endseen == 0) {
 249         if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
 250             printf("zf_read: fill error\n");
 251             return(EIO);
 252         }
 253         if (zf->zf_zstream.avail_in == 0) {             /* oops, unexpected EOF */
 254             printf("zf_read: unexpected EOF\n");
 255             if (zf->zf_zstream.avail_out == size)
 256                 return(EIO);
 257             break;
 258         }
 259
 260         error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */
 261         if (error == Z_STREAM_END) {                    /* EOF, all done */
 262             zf->zf_endseen = 1;
 263             break;
 264         }
 265         if (error != Z_OK) {                            /* argh, decompression error */
 266             printf("inflate: %s\n", zf->zf_zstream.msg);
 267             return(EIO);
 268         }
 269     }
 270     if (resid != NULL)
 271         *resid = zf->zf_zstream.avail_out;
 272     return(0);
 273 }
 274
 275 static int
 276 zf_rewind(struct open_file *f)
 277 {
 278     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 279
 280     if (lseek(zf->zf_rawfd, zf->zf_dataoffset, SEEK_SET) == -1)
 281         return(-1);
 282     zf->zf_zstream.avail_in = 0;
 283     zf->zf_zstream.next_in = NULL;
 284     zf->zf_endseen = 0;
 285     (void)inflateReset(&zf->zf_zstream);
 286
 287     return(0);
 288 }
 289
 290 static off_t
 291 zf_seek(struct open_file *f, off_t offset, int where)
 292 {
 293     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 294     off_t               target;
 295     char                discard[16];
 296
 297     switch (where) {
 298     case SEEK_SET:
 299         target = offset;
 300         break;
 301     case SEEK_CUR:
 302         target = offset + zf->zf_zstream.total_out;
 303         break;
 304     case SEEK_END:
 305         target = -1;
 306     default:
 307         errno = EINVAL;
 308         return(-1);
 309     }
 310
 311     /* rewind if required */
 312     if (target < zf->zf_zstream.total_out && zf_rewind(f) != 0)
 313         return(-1);
 314
 315     /* skip forwards if required */
 316     while (target > zf->zf_zstream.total_out) {
 317         errno = zf_read(f, discard, min(sizeof(discard),
 318             target - zf->zf_zstream.total_out), NULL);
 319         if (errno)
 320             return(-1);
 321     }
 322     /* This is where we are (be honest if we overshot) */
 323     return(zf->zf_zstream.total_out);
 324 }
 325
 326
 327 static int
 328 zf_stat(struct open_file *f, struct stat *sb)
 329 {
 330     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 331     int                 result, res;
 332     off_t               pos1, pos2;
 333     uint32_t            size;
 334
 335     /* stat as normal, but indicate that size is unknown */
 336     if ((result = fstat(zf->zf_rawfd, sb)) == 0) {
 337         if (sb->st_size == -1)
 338             return (result);
 339         pos1 = lseek(zf->zf_rawfd, 0, SEEK_CUR);
 340         pos2 = lseek(zf->zf_rawfd, sb->st_size - 4, SEEK_SET);
 341         if (pos2 != -1) {
 342             if (read(zf->zf_rawfd, &size, 4) == 4)
 343                 sb->st_size = (off_t) size;
 344             else
 345                 sb->st_size = -1;
 346         } else
 347             sb->st_size = -1;
 348
 349         pos1 = lseek(zf->zf_rawfd, pos1, SEEK_SET);
 350     }
 351     return(result);
 352 }