lib/libstand/zipfs.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  * $FreeBSD: src/lib/libstand/zipfs.c,v 1.4.2.4 2002/04/08 13:50:09 sobomax Exp $
  27  * $DragonFly: src/lib/libstand/zipfs.c,v 1.2 2003/06/17 04:26:51 dillon Exp $
  28  *
  29  */
  30
  31 #include "stand.h"
  32
  33 #include <sys/stat.h>
  34 #include <string.h>
  35 #include <zlib.h>
  36
  37 #define Z_BUFSIZE 2048  /* XXX larger? */
  38
  39 struct z_file
  40 {
  41     int                 zf_rawfd;
  42     z_stream            zf_zstream;
  43     char                zf_buf[Z_BUFSIZE];
  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 zipfs_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 #if 0
  65 void *
  66 calloc(int items, size_t size)
  67 {
  68     return(malloc(items * size));
  69 }
  70 #endif
  71
  72 static int
  73 zf_fill(struct z_file *zf)
  74 {
  75     int         result;
  76     int         req;
  77
  78     req = Z_BUFSIZE - zf->zf_zstream.avail_in;
  79     result = 0;
  80
  81     /* If we need more */
  82     if (req > 0) {
  83         /* move old data to bottom of buffer */
  84         if (req < Z_BUFSIZE)
  85             bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req);
  86
  87         /* read to fill buffer and update availibility data */
  88         result = read(zf->zf_rawfd, zf->zf_buf + zf->zf_zstream.avail_in, req);
  89         zf->zf_zstream.next_in = zf->zf_buf;
  90         if (result >= 0)
  91             zf->zf_zstream.avail_in += result;
  92     }
  93     return(result);
  94 }
  95
  96 /*
  97  * Adapted from get_byte/check_header in libz
  98  *
  99  * Returns 0 if the header is OK, nonzero if not.
 100  */
 101 static int
 102 get_byte(struct z_file *zf)
 103 {
 104     if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1))
 105         return(-1);
 106     zf->zf_zstream.avail_in--;
 107     return(*(zf->zf_zstream.next_in)++);
 108 }
 109
 110 static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */
 111
 112 /* gzip flag byte */
 113 #define ASCII_FLAG      0x01 /* bit 0 set: file probably ascii text */
 114 #define HEAD_CRC        0x02 /* bit 1 set: header CRC present */
 115 #define EXTRA_FIELD     0x04 /* bit 2 set: extra field present */
 116 #define ORIG_NAME       0x08 /* bit 3 set: original file name present */
 117 #define COMMENT         0x10 /* bit 4 set: file comment present */
 118 #define RESERVED        0xE0 /* bits 5..7: reserved */
 119
 120 static int
 121 check_header(struct z_file *zf)
 122 {
 123     int         method; /* method byte */
 124     int         flags;  /* flags byte */
 125     uInt        len;
 126     int         c;
 127
 128     /* Check the gzip magic header */
 129     for (len = 0; len < 2; len++) {
 130         c = get_byte(zf);
 131         if (c != gz_magic[len]) {
 132             return(1);
 133         }
 134     }
 135     method = get_byte(zf);
 136     flags = get_byte(zf);
 137     if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
 138         return(1);
 139     }
 140
 141     /* Discard time, xflags and OS code: */
 142     for (len = 0; len < 6; len++) (void)get_byte(zf);
 143
 144     if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */
 145         len  =  (uInt)get_byte(zf);
 146         len += ((uInt)get_byte(zf))<<8;
 147         /* len is garbage if EOF but the loop below will quit anyway */
 148         while (len-- != 0 && get_byte(zf) != -1) ;
 149     }
 150     if ((flags & ORIG_NAME) != 0) { /* skip the original file name */
 151         while ((c = get_byte(zf)) != 0 && c != -1) ;
 152     }
 153     if ((flags & COMMENT) != 0) {   /* skip the .gz file comment */
 154         while ((c = get_byte(zf)) != 0 && c != -1) ;
 155     }
 156     if ((flags & HEAD_CRC) != 0) {  /* skip the header crc */
 157         for (len = 0; len < 2; len++) c = get_byte(zf);
 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")
 179             || !strcmp(cp, ".bz2") || !strcmp(cp, ".split")))
 180         return(ENOENT);
 181
 182     /* Construct new name */
 183     zfname = malloc(strlen(fname) + 4);
 184     if (zfname == NULL)
 185         return(ENOMEM);
 186     sprintf(zfname, "%s.gz", fname);
 187
 188     /* Try to open the compressed datafile */
 189     rawfd = open(zfname, O_RDONLY);
 190     free(zfname);
 191     if (rawfd == -1)
 192         return(ENOENT);
 193
 194     if (fstat(rawfd, &sb) < 0) {
 195         printf("zf_open: stat failed\n");
 196         close(rawfd);
 197         return(ENOENT);
 198     }
 199     if (!S_ISREG(sb.st_mode)) {
 200         printf("zf_open: not a file\n");
 201         close(rawfd);
 202         return(EISDIR);                 /* best guess */
 203     }
 204
 205     /* Allocate a z_file structure, populate it */
 206     zf = malloc(sizeof(struct z_file));
 207     if (zf == NULL)
 208         return(ENOMEM);
 209     bzero(zf, sizeof(struct z_file));
 210     zf->zf_rawfd = rawfd;
 211
 212     /* Verify that the file is gzipped (XXX why do this afterwards?) */
 213     if (check_header(zf)) {
 214         close(zf->zf_rawfd);
 215         inflateEnd(&(zf->zf_zstream));
 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, zf->zf_zstream.msg);
 223         close(zf->zf_rawfd);
 224         free(zf);
 225         return(EIO);
 226     }
 227
 228     /* Looks OK, we'll take it */
 229     f->f_fsdata = zf;
 230     return(0);
 231 }
 232
 233 static int
 234 zf_close(struct open_file *f)
 235 {
 236     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 237
 238     f->f_fsdata = NULL;
 239     if (zf) {
 240         inflateEnd(&(zf->zf_zstream));
 241         close(zf->zf_rawfd);
 242         free(zf);
 243     }
 244     return(0);
 245 }
 246
 247 static int
 248 zf_read(struct open_file *f, void *buf, size_t size, size_t *resid)
 249 {
 250     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 251     int                 error;
 252
 253     zf->zf_zstream.next_out = buf;                      /* where and how much */
 254     zf->zf_zstream.avail_out = size;
 255
 256     while (zf->zf_zstream.avail_out) {
 257         if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) {
 258             printf("zf_read: fill error\n");
 259             return(-1);
 260         }
 261         if (zf->zf_zstream.avail_in == 0) {             /* oops, unexpected EOF */
 262             printf("zf_read: unexpected EOF\n");
 263             break;
 264         }
 265
 266         error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */
 267         if (error == Z_STREAM_END) {                    /* EOF, all done */
 268             break;
 269         }
 270         if (error != Z_OK) {                            /* argh, decompression error */
 271             printf("inflate: %s\n", zf->zf_zstream.msg);
 272             errno = EIO;
 273             return(-1);
 274         }
 275     }
 276     if (resid != NULL)
 277         *resid = zf->zf_zstream.avail_out;
 278     return(0);
 279 }
 280
 281 static off_t
 282 zf_seek(struct open_file *f, off_t offset, int where)
 283 {
 284     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 285     off_t               target;
 286     char                discard[16];
 287
 288     switch (where) {
 289     case SEEK_SET:
 290         target = offset;
 291         break;
 292     case SEEK_CUR:
 293         target = offset + zf->zf_zstream.total_out;
 294         break;
 295     default:
 296         target = -1;
 297     }
 298
 299     /* Can we get there from here? */
 300     if (target < zf->zf_zstream.total_out) {
 301         errno = EOFFSET;
 302         return -1;
 303     }
 304
 305     /* skip forwards if required */
 306     while (target > zf->zf_zstream.total_out) {
 307         if (zf_read(f, discard, min(sizeof(discard), target - zf->zf_zstream.total_out), NULL) == -1)
 308             return(-1);
 309     }
 310     /* This is where we are (be honest if we overshot) */
 311     return (zf->zf_zstream.total_out);
 312 }
 313
 314
 315 static int
 316 zf_stat(struct open_file *f, struct stat *sb)
 317 {
 318     struct z_file       *zf = (struct z_file *)f->f_fsdata;
 319     int                 result;
 320
 321     /* stat as normal, but indicate that size is unknown */
 322     if ((result = fstat(zf->zf_rawfd, sb)) == 0)
 323         sb->st_size = -1;
 324     return(result);
 325 }
 326
 327
 328