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 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 * Copyright 2025 MNX Cloud, Inc. 26 */ 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 <sys/kobj.h> 38 #include <zlib.h> 39 #include <sys/sunddi.h> 40 41 #define MAX_DECOMP_BUFS 8 42 #define GZIP_ID_BYTE_1 0x1f 43 #define GZIP_ID_BYTE_2 0x8b 44 #define GZIP_CM_DEFLATE 0x08 45 #define SEEKBUFSIZE 8192 46 47 extern int bootrd_debug; 48 extern void *bkmem_alloc(size_t); 49 extern void bkmem_free(void *, size_t); 50 51 caddr_t scratch_bufs[MAX_DECOMP_BUFS]; /* array of free scratch mem bufs */ 52 int decomp_bufcnt; /* total no, of allocated decomp bufs */ 53 int free_dcomp_bufs; /* no. of free decomp bufs */ 54 char seek_scrbuf[SEEKBUFSIZE]; /* buffer for seeking */ 55 int cf_debug = 0; /* non-zero enables debug prints */ 56 57 void * 58 cf_alloc(void *opaque, unsigned int items, unsigned int size) 59 { 60 fileid_t *filep; 61 unsigned int nbytes; 62 caddr_t ptr; 63 64 filep = (fileid_t *)opaque; 65 nbytes = roundup(items * size, sizeof (long)); 66 if (nbytes > (DECOMP_BUFSIZE - filep->fi_dcscrused)) { 67 ptr = bkmem_alloc(nbytes); 68 } else { 69 ptr = &filep->fi_dcscrbuf[filep->fi_dcscrused]; 70 filep->fi_dcscrused += nbytes; 71 } 72 bzero(ptr, nbytes); 73 return (ptr); 74 } 75 76 /* 77 * Decompression scratch memory free routine, does nothing since we free 78 * the entire scratch area all at once on file close. 79 */ 80 void 81 cf_free(void *opaque __unused, void *addr __unused) 82 { 83 } 84 85 /* 86 * Read the first block of the file described by filep and determine if 87 * the file is gzip-compressed. If so, the compressed flag will be set 88 * in the fileid_t struct pointed to by filep and it will be initialized 89 * for doing decompression on reads to the file. 90 */ 91 int 92 cf_check_compressed(fileid_t *filep) 93 { 94 unsigned char *filebytes; 95 z_stream *zsp; 96 97 /* 98 * checking for a dcfs compressed file first would involve: 99 * 100 * if (filep->fi_inode->i_cflags & ICOMPRESS) 101 * filep->fi_flags |= FI_COMPRESSED; 102 */ 103 104 /* 105 * If the file is not long enough to check for a 106 * decompression header then return not compressed. 107 */ 108 if (filep->fi_inode->i_size < 3) 109 return (0); 110 filep->fi_offset = 0; 111 if ((filep->fi_getblock)(filep) == -1) 112 return (-1); 113 filep->fi_offset = 0; 114 filep->fi_count = 0; 115 filep->fi_cfoff = 0; 116 filebytes = (unsigned char *)filep->fi_memp; 117 if (filebytes[0] != GZIP_ID_BYTE_1 || 118 filebytes[1] != GZIP_ID_BYTE_2 || 119 filebytes[2] != GZIP_CM_DEFLATE) 120 return (0); /* not compressed */ 121 filep->fi_flags |= FI_COMPRESSED; 122 123 if (cf_debug) 124 kobj_printf("file %s is compressed\n", filep->fi_path); 125 126 /* 127 * Allocate decompress scratch buffer 128 */ 129 if (free_dcomp_bufs) { 130 filep->fi_dcscrbuf = scratch_bufs[--free_dcomp_bufs]; 131 } else { 132 filep->fi_dcscrbuf = bkmem_alloc(DECOMP_BUFSIZE); 133 decomp_bufcnt++; 134 } 135 filep->fi_dcscrused = 0; 136 zsp = bkmem_alloc(sizeof (*zsp)); 137 filep->fi_dcstream = zsp; 138 /* 139 * Initialize the decompression stream. Adding 16 to the window size 140 * indicates that zlib should expect a gzip header. 141 */ 142 bzero(zsp, sizeof (*zsp)); 143 zsp->opaque = filep; 144 zsp->zalloc = cf_alloc; 145 zsp->zfree = cf_free; 146 zsp->avail_in = 0; 147 zsp->next_in = NULL; 148 zsp->avail_out = 0; 149 zsp->next_out = NULL; 150 if (inflateInit2(zsp, MAX_WBITS | 0x20) != Z_OK) { 151 if (cf_debug) 152 kobj_printf("inflateInit2() failed\n"); 153 return (-1); 154 } 155 return (0); 156 } 157 158 /* 159 * If the file described by fileid_t struct at *filep is compressed 160 * free any resources associated with the decompression. (decompression 161 * buffer, etc.). 162 */ 163 void 164 cf_close(fileid_t *filep) 165 { 166 if ((filep->fi_flags & FI_COMPRESSED) == 0) 167 return; 168 if (cf_debug) 169 kobj_printf("cf_close: %s\n", filep->fi_path); 170 (void) inflateEnd(filep->fi_dcstream); 171 bkmem_free(filep->fi_dcstream, sizeof (z_stream)); 172 if (free_dcomp_bufs == MAX_DECOMP_BUFS) { 173 bkmem_free(filep->fi_dcscrbuf, DECOMP_BUFSIZE); 174 } else { 175 scratch_bufs[free_dcomp_bufs++] = filep->fi_dcscrbuf; 176 } 177 } 178 179 void 180 cf_rewind(fileid_t *filep) 181 { 182 z_stream *zsp; 183 184 if (cf_debug) 185 kobj_printf("cf_rewind: %s\n", filep->fi_path); 186 zsp = filep->fi_dcstream; 187 zsp->avail_in = 0; 188 zsp->next_in = NULL; 189 (void) inflateReset(zsp); 190 filep->fi_cfoff = 0; 191 } 192 193 #define FLG_FHCRC 0x02 /* crc field present */ 194 #define FLG_FEXTRA 0x04 /* "extra" field present */ 195 #define FLG_FNAME 0x08 /* file name field present */ 196 #define FLG_FCOMMENT 0x10 /* comment field present */ 197 198 /* 199 * Read at the current uncompressed offset from the compressed file described 200 * by *filep. Will return decompressed data. 201 */ 202 int 203 cf_read(fileid_t *filep, caddr_t buf, size_t count) 204 { 205 z_stream *zsp; 206 struct inode *ip; 207 int err = Z_OK; 208 int infbytes; 209 off_t soff; 210 caddr_t smemp; 211 212 if (cf_debug) 213 kobj_printf("cf_read: %s %lx bytes\n", filep->fi_path, count); 214 zsp = filep->fi_dcstream; 215 ip = filep->fi_inode; 216 if (cf_debug) 217 kobj_printf(" reading at offset %lx\n", zsp->total_out); 218 zsp->next_out = (unsigned char *)buf; 219 zsp->avail_out = count; 220 while (zsp->avail_out != 0) { 221 if (zsp->avail_in == 0 && filep->fi_cfoff < ip->i_size) { 222 /* 223 * read a block of the file to inflate 224 */ 225 soff = filep->fi_offset; 226 smemp = filep->fi_memp; 227 filep->fi_memp = NULL; 228 filep->fi_offset = filep->fi_cfoff; 229 filep->fi_count = 0; 230 if ((*filep->fi_getblock)(filep) == -1) 231 return (-1); 232 filep->fi_offset = soff; 233 zsp->next_in = (unsigned char *)filep->fi_memp; 234 zsp->avail_in = filep->fi_count; 235 filep->fi_memp = smemp; 236 filep->fi_cfoff += filep->fi_count; 237 } 238 infbytes = zsp->avail_out; 239 if (cf_debug) { 240 kobj_printf("attempting inflate of %x bytes to " 241 "buf at: %lx\n", 242 zsp->avail_out, (unsigned long)zsp->next_out); 243 } 244 err = inflate(zsp, Z_NO_FLUSH); 245 infbytes -= zsp->avail_out; 246 if (cf_debug) { 247 kobj_printf("inflated %x bytes, errcode=%d\n", 248 infbytes, err); 249 } 250 /* 251 * break out if we hit end of the compressed file 252 * or the end of the compressed byte stream 253 */ 254 if (filep->fi_cfoff >= ip->i_size || err == Z_STREAM_END) 255 break; 256 } 257 if (cf_debug) { 258 kobj_printf("cf_read: returned %lx bytes\n", 259 count - zsp->avail_out); 260 } 261 return (count - zsp->avail_out); 262 } 263 264 /* 265 * Seek to the location specified by addr 266 */ 267 void 268 cf_seek(fileid_t *filep, off_t addr, int whence) 269 { 270 z_stream *zsp; 271 int readsz; 272 273 if (cf_debug) 274 kobj_printf("cf_seek: %s to %lx\n", filep->fi_path, addr); 275 zsp = filep->fi_dcstream; 276 if (whence == SEEK_CUR) 277 addr += zsp->total_out; 278 /* 279 * To seek backwards, must rewind and seek forwards 280 */ 281 if (addr < zsp->total_out) { 282 cf_rewind(filep); 283 filep->fi_offset = 0; 284 } else { 285 addr -= zsp->total_out; 286 } 287 while (addr > 0) { 288 readsz = MIN(addr, SEEKBUFSIZE); 289 (void) cf_read(filep, seek_scrbuf, readsz); 290 addr -= readsz; 291 } 292 } 293