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Diffstat (limited to 'unzip.c')
| -rw-r--r-- | unzip.c | 213 |
1 files changed, 213 insertions, 0 deletions
@@ -0,0 +1,213 @@ +/* unzip.c -- decompress files in gzip or pkzip format. + + Copyright (C) 1997-1999, 2009-2016 Free Software Foundation, Inc. + Copyright (C) 1992-1993 Jean-loup Gailly + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* + * The code in this file is derived from the file funzip.c written + * and put in the public domain by Mark Adler. + */ + +/* + This version can extract files in gzip or pkzip format. + For the latter, only the first entry is extracted, and it has to be + either deflated or stored. + */ + +#include <config.h> +#include "tailor.h" +#include "gzip.h" + +/* PKZIP header definitions */ +#define LOCSIG 0x04034b50L /* four-byte lead-in (lsb first) */ +#define LOCFLG 6 /* offset of bit flag */ +#define CRPFLG 1 /* bit for encrypted entry */ +#define EXTFLG 8 /* bit for extended local header */ +#define LOCHOW 8 /* offset of compression method */ +/* #define LOCTIM 10 UNUSED file mod time (for decryption) */ +#define LOCCRC 14 /* offset of crc */ +#define LOCSIZ 18 /* offset of compressed size */ +#define LOCLEN 22 /* offset of uncompressed length */ +#define LOCFIL 26 /* offset of file name field length */ +#define LOCEXT 28 /* offset of extra field length */ +#define LOCHDR 30 /* size of local header, including sig */ +#define EXTHDR 16 /* size of extended local header, inc sig */ +#define RAND_HEAD_LEN 12 /* length of encryption random header */ + + +/* Globals */ + +static int decrypt; /* flag to turn on decryption */ +static int pkzip = 0; /* set for a pkzip file */ +static int ext_header = 0; /* set if extended local header */ + +/* =========================================================================== + * Check zip file and advance inptr to the start of the compressed data. + * Get ofname from the local header if necessary. + */ +int check_zipfile(in) + int in; /* input file descriptors */ +{ + uch *h = inbuf + inptr; /* first local header */ + + ifd = in; + + /* Check validity of local header, and skip name and extra fields */ + inptr += LOCHDR + SH(h + LOCFIL) + SH(h + LOCEXT); + + if (inptr > insize || LG(h) != LOCSIG) { + fprintf(stderr, "\n%s: %s: not a valid zip file\n", + program_name, ifname); + exit_code = ERROR; + return ERROR; + } + method = h[LOCHOW]; + if (method != STORED && method != DEFLATED) { + fprintf(stderr, + "\n%s: %s: first entry not deflated or stored -- use unzip\n", + program_name, ifname); + exit_code = ERROR; + return ERROR; + } + + /* If entry encrypted, decrypt and validate encryption header */ + if ((decrypt = h[LOCFLG] & CRPFLG) != 0) { + fprintf(stderr, "\n%s: %s: encrypted file -- use unzip\n", + program_name, ifname); + exit_code = ERROR; + return ERROR; + } + + /* Save flags for unzip() */ + ext_header = (h[LOCFLG] & EXTFLG) != 0; + pkzip = 1; + + /* Get ofname and time stamp from local header (to be done) */ + return OK; +} + +/* =========================================================================== + * Unzip in to out. This routine works on both gzip and pkzip files. + * + * IN assertions: the buffer inbuf contains already the beginning of + * the compressed data, from offsets inptr to insize-1 included. + * The magic header has already been checked. The output buffer is cleared. + */ +int unzip(in, out) + int in, out; /* input and output file descriptors */ +{ + ulg orig_crc = 0; /* original crc */ + ulg orig_len = 0; /* original uncompressed length */ + int n; + uch buf[EXTHDR]; /* extended local header */ + int err = OK; + + ifd = in; + ofd = out; + + updcrc(NULL, 0); /* initialize crc */ + + if (pkzip && !ext_header) { /* crc and length at the end otherwise */ + orig_crc = LG(inbuf + LOCCRC); + orig_len = LG(inbuf + LOCLEN); + } + + /* Decompress */ + if (method == DEFLATED) { + + int res = inflate(); + + if (res == 3) { + xalloc_die (); + } else if (res != 0) { + gzip_error ("invalid compressed data--format violated"); + } + + } else if (pkzip && method == STORED) { + + register ulg n = LG(inbuf + LOCLEN); + + if (n != LG(inbuf + LOCSIZ) - (decrypt ? RAND_HEAD_LEN : 0)) { + + fprintf(stderr, "len %lu, siz %lu\n", n, LG(inbuf + LOCSIZ)); + gzip_error ("invalid compressed data--length mismatch"); + } + while (n--) { + uch c = (uch)get_byte(); + put_ubyte(c); + } + flush_window(); + } else { + gzip_error ("internal error, invalid method"); + } + + /* Get the crc and original length */ + if (!pkzip) { + /* crc32 (see algorithm.doc) + * uncompressed input size modulo 2^32 + */ + for (n = 0; n < 8; n++) { + buf[n] = (uch)get_byte(); /* may cause an error if EOF */ + } + orig_crc = LG(buf); + orig_len = LG(buf+4); + + } else if (ext_header) { /* If extended header, check it */ + /* signature - 4bytes: 0x50 0x4b 0x07 0x08 + * CRC-32 value + * compressed size 4-bytes + * uncompressed size 4-bytes + */ + for (n = 0; n < EXTHDR; n++) { + buf[n] = (uch)get_byte(); /* may cause an error if EOF */ + } + orig_crc = LG(buf+4); + orig_len = LG(buf+12); + } + + /* Validate decompression */ + if (orig_crc != updcrc(outbuf, 0)) { + fprintf(stderr, "\n%s: %s: invalid compressed data--crc error\n", + program_name, ifname); + err = ERROR; + } + if (orig_len != (ulg)(bytes_out & 0xffffffff)) { + fprintf(stderr, "\n%s: %s: invalid compressed data--length error\n", + program_name, ifname); + err = ERROR; + } + + /* Check if there are more entries in a pkzip file */ + if (pkzip && inptr + 4 < insize && LG(inbuf+inptr) == LOCSIG) { + if (to_stdout) { + WARN((stderr, + "%s: %s has more than one entry--rest ignored\n", + program_name, ifname)); + } else { + /* Don't destroy the input zip file */ + fprintf(stderr, + "%s: %s has more than one entry -- unchanged\n", + program_name, ifname); + err = ERROR; + } + } + ext_header = pkzip = 0; /* for next file */ + if (err == OK) return OK; + exit_code = ERROR; + if (!test) abort_gzip(); + return err; +} |