/* * Copyright (c) 1998 Michael Smith. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $Id: zipfs.c,v 1.1.1.1 1998/08/20 08:19:55 msmith Exp $ * */ #include "stand.h" #include #include #include #define Z_BUFSIZE 2048 /* XXX larger? */ struct z_file { int zf_rawfd; z_stream zf_zstream; char zf_buf[Z_BUFSIZE]; }; static int zf_fill(struct z_file *z); static int zf_open(const char *path, struct open_file *f); static int zf_close(struct open_file *f); static int zf_read(struct open_file *f, void *buf, size_t size, size_t *resid); static off_t zf_seek(struct open_file *f, off_t offset, int where); static int zf_stat(struct open_file *f, struct stat *sb); struct fs_ops zipfs_fsops = { "zip", zf_open, zf_close, zf_read, null_write, zf_seek, zf_stat }; void * calloc(int items, size_t size) { return(malloc(items * size)); } static int zf_fill(struct z_file *zf) { int result; int req; req = Z_BUFSIZE - zf->zf_zstream.avail_in; result = 0; /* If we need more */ if (req > 0) { /* move old data to bottom of buffer */ if (req < Z_BUFSIZE) bcopy(zf->zf_buf + req, zf->zf_buf, Z_BUFSIZE - req); /* read to fill buffer and update availibility data */ result = read(zf->zf_rawfd, zf->zf_buf + zf->zf_zstream.avail_in, req); zf->zf_zstream.next_in = zf->zf_buf; if (result >= 0) zf->zf_zstream.avail_in += result; } return(result); } /* * Adapted from get_byte/check_header in libz * * Returns 0 if the header is OK, nonzero if not. */ static int get_byte(struct z_file *zf) { if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) return(-1); zf->zf_zstream.avail_in--; return(*(zf->zf_zstream.next_in)++); } static int gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */ /* gzip flag byte */ #define ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */ #define HEAD_CRC 0x02 /* bit 1 set: header CRC present */ #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ #define COMMENT 0x10 /* bit 4 set: file comment present */ #define RESERVED 0xE0 /* bits 5..7: reserved */ static int check_header(struct z_file *zf) { int method; /* method byte */ int flags; /* flags byte */ uInt len; int c; /* Check the gzip magic header */ for (len = 0; len < 2; len++) { c = get_byte(zf); if (c != gz_magic[len]) { return(1); } } method = get_byte(zf); flags = get_byte(zf); if (method != Z_DEFLATED || (flags & RESERVED) != 0) { return(1); } /* Discard time, xflags and OS code: */ for (len = 0; len < 6; len++) (void)get_byte(zf); if ((flags & EXTRA_FIELD) != 0) { /* skip the extra field */ len = (uInt)get_byte(zf); len += ((uInt)get_byte(zf))<<8; /* len is garbage if EOF but the loop below will quit anyway */ while (len-- != 0 && get_byte(zf) != -1) ; } if ((flags & ORIG_NAME) != 0) { /* skip the original file name */ while ((c = get_byte(zf)) != 0 && c != -1) ; } if ((flags & COMMENT) != 0) { /* skip the .gz file comment */ while ((c = get_byte(zf)) != 0 && c != -1) ; } if ((flags & HEAD_CRC) != 0) { /* skip the header crc */ for (len = 0; len < 2; len++) c = get_byte(zf); } /* if there's data left, we're in business */ return((c == -1) ? 1 : 0); } static int zf_open(const char *fname, struct open_file *f) { static char *zfname; int rawfd; struct z_file *zf; char *cp; int error; struct stat sb; /* Have to be in "just read it" mode */ if (f->f_flags != F_READ) return(EPERM); /* If the name already ends in .gz, ignore it */ if ((cp = strrchr(fname, '.')) && !strcmp(cp, ".gz")) return(ENOENT); /* Construct new name */ zfname = malloc(strlen(fname) + 3); sprintf(zfname, "%s.gz", fname); /* Try to open the compressed datafile */ rawfd = open(zfname, O_RDONLY); free(zfname); if (rawfd == -1) return(ENOENT); if (fstat(rawfd, &sb) < 0) { printf("zf_open: stat failed\n"); close(rawfd); return(ENOENT); } if (!S_ISREG(sb.st_mode)) { printf("zf_open: not a file\n"); close(rawfd); return(EISDIR); /* best guess */ } /* Allocate a z_file structure, populate it */ zf = malloc(sizeof(struct z_file)); bzero(zf, sizeof(struct z_file)); zf->zf_rawfd = rawfd; /* Verify that the file is gzipped (XXX why do this afterwards?) */ if (check_header(zf)) { close(zf->zf_rawfd); inflateEnd(&(zf->zf_zstream)); free(zf); return(EFTYPE); } /* Initialise the inflation engine */ if ((error = inflateInit2(&(zf->zf_zstream), -15)) != Z_OK) { printf("zf_open: inflateInit returned %d : %s\n", error, zf->zf_zstream.msg); close(zf->zf_rawfd); free(zf); return(EIO); } /* Looks OK, we'll take it */ f->f_fsdata = zf; return(0); } static int zf_close(struct open_file *f) { struct z_file *zf = (struct z_file *)f->f_fsdata; inflateEnd(&(zf->zf_zstream)); close(zf->zf_rawfd); free(zf); return(0); } static int zf_read(struct open_file *f, void *buf, size_t size, size_t *resid) { struct z_file *zf = (struct z_file *)f->f_fsdata; int error; zf->zf_zstream.next_out = buf; /* where and how much */ zf->zf_zstream.avail_out = size; while (zf->zf_zstream.avail_out) { if ((zf->zf_zstream.avail_in == 0) && (zf_fill(zf) == -1)) { printf("zf_read: fill error\n"); return(-1); } if (zf->zf_zstream.avail_in == 0) { /* oops, unexpected EOF */ printf("zf_read: unexpected EOF\n"); break; } error = inflate(&zf->zf_zstream, Z_SYNC_FLUSH); /* decompression pass */ if (error == Z_STREAM_END) { /* EOF, all done */ break; } if (error != Z_OK) { /* argh, decompression error */ printf("inflate: %s\n", zf->zf_zstream.msg); errno = EIO; return(-1); } } if (resid != NULL) *resid = zf->zf_zstream.avail_out; return(0); } static off_t zf_seek(struct open_file *f, off_t offset, int where) { struct z_file *zf = (struct z_file *)f->f_fsdata; off_t target; char discard[16]; switch (where) { case SEEK_SET: target = offset; break; case SEEK_CUR: target = offset + zf->zf_zstream.total_out; break; default: target = -1; } /* Can we get there from here? */ if (target < zf->zf_zstream.total_out) { errno = EOFFSET; return -1; } /* skip forwards if required */ while (target > zf->zf_zstream.total_out) { if (zf_read(f, discard, min(sizeof(discard), target - zf->zf_zstream.total_out), NULL) == -1) return(-1); } /* This is where we are (be honest if we overshot) */ return (zf->zf_zstream.total_out); } static int zf_stat(struct open_file *f, struct stat *sb) { struct z_file *zf = (struct z_file *)f->f_fsdata; int result; /* stat as normal, but indicate that size is unknown */ if ((result = fstat(zf->zf_rawfd, sb)) == 0) sb->st_size = -1; return(result); }