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         .fs_name = "zip",
  55         .fo_open = zf_open,
  56         .fo_close = zf_close,
  57         .fo_read = zf_read,
  58         .fo_write = null_write,
  59         .fo_seek = zf_seek,
  60         .fo_stat = zf_stat,
  61         .fo_readdir = 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,
  81                     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++)
 138                 (void) get_byte(zf, &zf->zf_dataoffset);
 139
 140         if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
 141                 len  =  (uInt)get_byte(zf, &zf->zf_dataoffset);
 142                 len += ((uInt)get_byte(zf, &zf->zf_dataoffset))<<8;
 143                 /* len is garbage if EOF but the loop below will quit anyway */
 144                 while (len-- != 0 && get_byte(zf, &zf->zf_dataoffset) != -1)
 145                         ;
 146         }
 147         if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
 148                 while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1)
 149                         ;
 150         }
 151         if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
 152                 while ((c = get_byte(zf, &zf->zf_dataoffset)) != 0 && c != -1)
 153                         ;
 154         }
 155         if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
 156                 for (len = 0; len < 2; len++)
 157                         c = get_byte(zf, &zf->zf_dataoffset);
 158         }
 159         /* if there's data left, we're in business */
 160         return ((c == -1) ? 1 : 0);
 161 }
 162
 163 static int
 164 zf_open(const char *fname, struct open_file *f)
 165 {
 166         char            *zfname;
 167         int             rawfd;
 168         struct z_file   *zf;
 169         char            *cp;
 170         int             error;
 171         struct stat     sb;
 172
 173         /* Have to be in "just read it" mode */
 174         if (f->f_flags != F_READ)
 175                 return (EPERM);
 176
 177         /* If the name already ends in .gz or .bz2, ignore it */
 178         if ((cp = strrchr(fname, '.')) && (strcmp(cp, ".gz") == 0 ||
 179             strcmp(cp, ".bz2") == 0 || strcmp(cp, ".split") == 0))
 180                 return (ENOENT);
 181
 182         /* Try to open the compressed datafile */
 183         rawfd = open(fname, O_RDONLY | F_GZIP);
 184         if (rawfd == -1) {
 185                 /* add .gz sufix and try again */
 186                 zfname = malloc(strlen(fname) + 4);
 187                 if (zfname == NULL)
 188                         return (ENOMEM);
 189                 sprintf(zfname, "%s.gz", fname);
 190                 rawfd = open(zfname, O_RDONLY);
 191                 free(zfname);
 192                 if (rawfd == -1)
 193                         return (ENOENT);
 194         }
 195
 196         if (fstat(rawfd, &sb) < 0) {
 197                 printf("zf_open: stat failed\n");
 198                 close(rawfd);
 199                 return (ENOENT);
 200         }
 201         if (!S_ISREG(sb.st_mode)) {
 202                 close(rawfd);
 203                 return (EISDIR);        /* best guess */
 204         }
 205
 206         /* Allocate a z_file structure, populate it */
 207         zf = malloc(sizeof (struct z_file));
 208         if (zf == NULL)
 209                 return (ENOMEM);
 210         bzero(zf, sizeof (struct z_file));
 211         zf->zf_rawfd = rawfd;
 212
 213         /* Verify that the file is gzipped */
 214         if (check_header(zf)) {
 215                 close(zf->zf_rawfd);
 216                 free(zf);
 217                 return (EFTYPE);
 218         }
 219
 220         /* Initialise the inflation engine */
 221         if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) {
 222                 printf("zf_open: inflateInit returned %d : %s\n", error,
 223                     zf->zf_zstream.msg);
 224                 close(zf->zf_rawfd);
 225                 free(zf);
 226                 return (EIO);
 227         }
 228
 229         /* Looks OK, we'll take it */
 230         f->f_fsdata = zf;
 231         return (0);
 232 }
 233
 234 static int
 235 zf_close(struct open_file *f)
 236 {
 237         struct z_file   *zf = (struct z_file *)f->f_fsdata;
 238
 239         inflateEnd(&(zf->zf_zstream));
 240         close(zf->zf_rawfd);
 241         free(zf);
 242         return (0);
 243 }
 244
 245 static int
 246 zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
 247 {
 248         struct z_file   *zf = (struct z_file *)f->f_fsdata;
 249         int             error;
 250
 251         zf->zf_zstream.next_out = buf;          /* where and how much */
 252         zf->zf_zstream.avail_out = size;
 253
 254         while (zf->zf_zstream.avail_out && zf->zf_endseen == 0) {
 255                 if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
 256                         printf("zf_read: fill error\n");
 257                         return (EIO);
 258                 }
 259                 if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */
 260                         printf("zf_read: unexpected EOF\n");
 261                         if (zf->zf_zstream.avail_out == size)
 262                                 return (EIO);
 263                         break;
 264                 }
 265
 266                 /* decompression pass */
 267                 error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH);
 268                 if (error == Z_STREAM_END) {    /* EOF, all done */
 269                         zf->zf_endseen = 1;
 270                         break;
 271                 }
 272                 if (error != Z_OK) {            /* argh, decompression error */
 273                         printf("inflate: %s\n", zf->zf_zstream.msg);
 274                         return (EIO);
 275                 }
 276         }
 277         if (resid != NULL)
 278                 *resid = zf->zf_zstream.avail_out;
 279         return (0);
 280 }
 281
 282 static int
 283 zf_rewind(struct open_file *f)
 284 {
 285         struct z_file   *zf = (struct z_file *)f->f_fsdata;
 286
 287         if (lseek(zf->zf_rawfd, zf->zf_dataoffset, SEEK_SET) == -1)
 288                 return (-1);
 289         zf->zf_zstream.avail_in = 0;
 290         zf->zf_zstream.next_in = NULL;
 291         zf->zf_endseen = 0;
 292         (void) inflateReset(&zf->zf_zstream);
 293
 294         return (0);
 295 }
 296
 297 static off_t
 298 zf_seek(struct open_file *f, off_t offset, int where)
 299 {
 300         struct z_file   *zf = (struct z_file *)f->f_fsdata;
 301         off_t           target;
 302         char            discard[16];
 303
 304         switch (where) {
 305         case SEEK_SET:
 306                 target = offset;
 307                 break;
 308         case SEEK_CUR:
 309                 target = offset + zf->zf_zstream.total_out;
 310                 break;
 311         default:
 312                 errno = EINVAL;
 313                 return (-1);
 314         }
 315
 316         /* rewind if required */
 317         if (target < zf->zf_zstream.total_out && zf_rewind(f) != 0)
 318                 return (-1);
 319
 320         /* skip forwards if required */
 321         while (target > zf->zf_zstream.total_out) {
 322                 errno = zf_read(f, discard, min(sizeof (discard),
 323                     target - zf->zf_zstream.total_out), NULL);
 324                 if (errno != 0)
 325                         return (-1);
 326         }
 327         /* This is where we are (be honest if we overshot) */
 328         return (zf->zf_zstream.total_out);
 329 }
 330
 331
 332 static int
 333 zf_stat(struct open_file *f, struct stat *sb)
 334 {
 335         struct z_file   *zf = (struct z_file *)f->f_fsdata;
 336         int             result;
 337         off_t           pos1, pos2;
 338         uint32_t        size;
 339
 340         /* stat as normal, but indicate that size is unknown */
 341         if ((result = fstat(zf->zf_rawfd, sb)) == 0) {
 342                 if (sb->st_size == -1)
 343                         return (result);
 344                 pos1 = lseek(zf->zf_rawfd, 0, SEEK_CUR);
 345                 pos2 = lseek(zf->zf_rawfd, sb->st_size - 4, SEEK_SET);
 346                 if (pos2 != -1) {
 347                         if (read(zf->zf_rawfd, &size, 4) == 4)
 348                                 sb->st_size = (off_t)size;
 349                         else
 350                                 sb->st_size = -1;
 351                 } else
 352                         sb->st_size = -1;
 353
 354                 pos1 = lseek(zf->zf_rawfd, pos1, SEEK_SET);
 355         }
 356         return (result);
 357 }