1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 /* 29 * Decompression module for stand alone file systems. 30 */ 31 32 #include <sys/param.h> 33 #include <sys/sysmacros.h> 34 #include <sys/vnode.h> 35 #include <sys/bootvfs.h> 36 #include <sys/filep.h> 37 #include <zmod/zlib.h> 38 39 #ifdef _BOOT 40 #include "../common/util.h" 41 #else 42 #include <sys/sunddi.h> 43 #endif 44 45 #define MAX_DECOMP_BUFS 8 46 #define GZIP_ID_BYTE_1 0x1f 47 #define GZIP_ID_BYTE_2 0x8b 48 #define GZIP_CM_DEFLATE 0x08 49 #define SEEKBUFSIZE 8192 50 51 #ifdef _BOOT 52 #define dprintf if (cf_debug) printf 53 #else 54 #define dprintf if (cf_debug) printf 55 56 #endif 57 58 extern int bootrd_debug; 59 extern void *bkmem_alloc(size_t); 60 extern void bkmem_free(void *, size_t); 61 62 caddr_t scratch_bufs[MAX_DECOMP_BUFS]; /* array of free scratch mem bufs */ 63 int decomp_bufcnt; /* total no, of allocated decomp bufs */ 64 int free_dcomp_bufs; /* no. of free decomp bufs */ 65 char seek_scrbuf[SEEKBUFSIZE]; /* buffer for seeking */ 66 int cf_debug; /* non-zero enables debug prints */ 67 68 void * 69 cf_alloc(void *opaque, unsigned int items, unsigned int size) 70 { 71 fileid_t *filep; 72 unsigned int nbytes; 73 caddr_t ptr; 74 75 filep = (fileid_t *)opaque; 76 nbytes = roundup(items * size, sizeof (long)); 77 if (nbytes > (DECOMP_BUFSIZE - filep->fi_dcscrused)) { 78 ptr = bkmem_alloc(nbytes); 79 } else { 80 ptr = &filep->fi_dcscrbuf[filep->fi_dcscrused]; 81 filep->fi_dcscrused += nbytes; 82 } 83 bzero(ptr, nbytes); 84 return (ptr); 85 } 86 87 /* 88 * Decompression scratch memory free routine, does nothing since we free 89 * the entire scratch area all at once on file close. 90 */ 91 /* ARGSUSED */ 92 void 93 cf_free(void *opaque, void *addr) 94 { 95 } 96 97 /* 98 * Read the first block of the file described by filep and determine if 99 * the file is gzip-compressed. If so, the compressed flag will be set 100 * in the fileid_t struct pointed to by filep and it will be initialized 101 * for doing decompression on reads to the file. 102 */ 103 int 104 cf_check_compressed(fileid_t *filep) 105 { 106 unsigned char *filebytes; 107 z_stream *zsp; 108 109 /* 110 * If the file is not long enough to check for a decompression header 111 * then return not compressed. 112 */ 113 if (filep->fi_inode->i_size < 3) 114 return (0); 115 filep->fi_offset = 0; 116 if ((filep->fi_getblock)(filep) == -1) 117 return (-1); 118 filep->fi_offset = 0; 119 filep->fi_count = 0; 120 filep->fi_cfoff = 0; 121 filebytes = (unsigned char *)filep->fi_memp; 122 if (filebytes[0] != GZIP_ID_BYTE_1 || filebytes[1] != GZIP_ID_BYTE_2 || 123 filebytes[2] != GZIP_CM_DEFLATE) 124 return (0); /* not compressed */ 125 filep->fi_flags |= FI_COMPRESSED; 126 127 dprintf("file %s is compressed\n", filep->fi_path); 128 129 /* 130 * Allocate decompress scratch buffer 131 */ 132 if (free_dcomp_bufs) { 133 filep->fi_dcscrbuf = scratch_bufs[--free_dcomp_bufs]; 134 } else { 135 filep->fi_dcscrbuf = bkmem_alloc(DECOMP_BUFSIZE); 136 decomp_bufcnt++; 137 } 138 filep->fi_dcscrused = 0; 139 zsp = bkmem_alloc(sizeof (*zsp)); 140 filep->fi_dcstream = zsp; 141 /* 142 * Initialize the decompression stream 143 */ 144 bzero(zsp, sizeof (*zsp)); 145 zsp->opaque = filep; 146 zsp->zalloc = cf_alloc; 147 zsp->zfree = cf_free; 148 zsp->avail_in = 0; 149 zsp->next_in = NULL; 150 zsp->avail_out = 0; 151 zsp->next_out = NULL; 152 if (inflateInit2(zsp, -MAX_WBITS) != Z_OK) 153 return (-1); 154 return (0); 155 } 156 157 /* 158 * If the file described by fileid_t struct at *filep is compressed 159 * free any resources associated with the decompression. (decompression 160 * buffer, etc.). 161 */ 162 void 163 cf_close(fileid_t *filep) 164 { 165 if ((filep->fi_flags & FI_COMPRESSED) == 0) 166 return; 167 dprintf("cf_close: %s\n", filep->fi_path); 168 (void) inflateEnd(filep->fi_dcstream); 169 bkmem_free(filep->fi_dcstream, sizeof (z_stream)); 170 if (free_dcomp_bufs == MAX_DECOMP_BUFS) { 171 bkmem_free(filep->fi_dcscrbuf, DECOMP_BUFSIZE); 172 } else { 173 scratch_bufs[free_dcomp_bufs++] = filep->fi_dcscrbuf; 174 } 175 } 176 177 void 178 cf_rewind(fileid_t *filep) 179 { 180 z_stream *zsp; 181 182 dprintf("cf_rewind: %s\n", filep->fi_path); 183 zsp = filep->fi_dcstream; 184 zsp->avail_in = 0; 185 zsp->next_in = NULL; 186 (void) inflateReset(zsp); 187 filep->fi_cfoff = 0; 188 } 189 190 #define FLG_FHCRC 0x02 /* crc field present */ 191 #define FLG_FEXTRA 0x04 /* "extra" field present */ 192 #define FLG_FNAME 0x08 /* file name field present */ 193 #define FLG_FCOMMENT 0x10 /* comment field present */ 194 195 /* 196 * Calculate the header length of a gzip compressed file 197 */ 198 static int 199 cf_headerlen(unsigned char *hp) 200 { 201 unsigned char flag; 202 int xlen, hlen = 0; 203 204 hlen += 3; /* skip ID bytes and compression method */ 205 flag = hp[hlen]; 206 hlen += 7; /* skip flag, mtime(4 bytes), xfl, and os */ 207 if (flag & FLG_FEXTRA) { 208 xlen = hp[hlen++]; 209 xlen += hp[hlen++] << 8; 210 hlen += xlen; /* skip extra field */ 211 } 212 if (flag & FLG_FNAME) 213 hlen += strlen((char *)&hp[hlen]) + 1; /* skip file name */ 214 if (flag & FLG_FCOMMENT) 215 hlen += strlen((char *)&hp[hlen]) + 1; /* skip comment */ 216 if (flag & FLG_FHCRC) 217 hlen += 2; /* skip crc */ 218 return (hlen); 219 } 220 221 /* 222 * Read at the current uncompressed offset from the compressed file described 223 * by *filep. Will return decompressed data. 224 */ 225 int 226 cf_read(fileid_t *filep, caddr_t buf, size_t count) 227 { 228 z_stream *zsp; 229 struct inode *ip; 230 int err = Z_OK; 231 int hlen, infbytes; 232 off_t soff; 233 caddr_t smemp; 234 235 dprintf("cf_read: %s ", filep->fi_path); 236 dprintf("%lx bytes\n", count); 237 zsp = filep->fi_dcstream; 238 ip = filep->fi_inode; 239 dprintf(" reading at offset %lx\n", zsp->total_out); 240 zsp->next_out = (unsigned char *)buf; 241 zsp->avail_out = count; 242 while (zsp->avail_out != 0) { 243 if (zsp->avail_in == 0 && filep->fi_cfoff < ip->i_size) { 244 /* 245 * read a block of the file to inflate 246 */ 247 soff = filep->fi_offset; 248 smemp = filep->fi_memp; 249 filep->fi_memp = NULL; 250 filep->fi_offset = filep->fi_cfoff; 251 filep->fi_count = 0; 252 if ((*filep->fi_getblock)(filep) == -1) 253 return (-1); 254 filep->fi_offset = soff; 255 zsp->next_in = (unsigned char *)filep->fi_memp; 256 zsp->avail_in = filep->fi_count; 257 filep->fi_memp = smemp; 258 /* 259 * If we are reading the first block of the file, we 260 * need to skip over the header bytes before inflating 261 */ 262 if (filep->fi_cfoff == 0) { 263 hlen = cf_headerlen(zsp->next_in); 264 zsp->next_in += hlen; 265 zsp->avail_in -= hlen; 266 } 267 filep->fi_cfoff += filep->fi_count; 268 } 269 infbytes = zsp->avail_out; 270 dprintf("attempting inflate of %x bytes to buf at: %lx\n", 271 zsp->avail_out, (unsigned long)zsp->next_out); 272 err = inflate(zsp, Z_NO_FLUSH); 273 infbytes -= zsp->avail_out; 274 dprintf("inflated %x bytes, errcode=%d\n", infbytes, err); 275 /* 276 * break out if we hit end of the compressed file 277 * or the end of the compressed byte stream 278 */ 279 if (filep->fi_cfoff >= ip->i_size || err == Z_STREAM_END) 280 break; 281 } 282 dprintf("cf_read: returned %lx bytes\n", count - zsp->avail_out); 283 return (count - zsp->avail_out); 284 } 285 286 /* 287 * Seek to the location specified by addr 288 */ 289 void 290 cf_seek(fileid_t *filep, off_t addr, int whence) 291 { 292 z_stream *zsp; 293 int readsz; 294 295 dprintf("cf_seek: %s ", filep->fi_path); 296 dprintf("to %lx\n", addr); 297 zsp = filep->fi_dcstream; 298 if (whence == SEEK_CUR) 299 addr += zsp->total_out; 300 /* 301 * To seek backwards, must rewind and seek forwards 302 */ 303 if (addr < zsp->total_out) { 304 cf_rewind(filep); 305 filep->fi_offset = 0; 306 } else { 307 addr -= zsp->total_out; 308 } 309 while (addr > 0) { 310 readsz = MIN(addr, SEEKBUFSIZE); 311 (void) cf_read(filep, seek_scrbuf, readsz); 312 addr -= readsz; 313 } 314 } 315