opkg: fix some initialisation and double free issues in libbb

[project/opkg-lede.git] / libbb / unzip.c

/* vi: set sw=4 ts=4: */
/*
 * gunzip implementation for busybox
 *
 * Based on GNU gzip v1.2.4 Copyright (C) 1992-1993 Jean-loup Gailly.
 *
 * Originally adjusted for busybox by Sven Rudolph <sr1@inf.tu-dresden.de>
 * based on gzip sources
 *
 * Adjusted further by Erik Andersen <andersee@debian.org> to support
 * files as well as stdin/stdout, and to generally behave itself wrt
 * command line handling.
 *
 * General cleanup to better adhere to the style guide and make use of
 * standard busybox functions by Glenn McGrath <bug1@optushome.com.au>
 *
 * 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 2 of the License, 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 *
 * gzip (GNU zip) -- compress files with zip algorithm and 'compress' interface
 * Copyright (C) 1992-1993 Jean-loup Gailly
 * The unzip code was written and put in the public domain by Mark Adler.
 * Portions of the lzw code are derived from the public domain 'compress'
 * written by Spencer Thomas, Joe Orost, James Woods, Jim McKie, Steve Davies,
 * Ken Turkowski, Dave Mack and Peter Jannesen.
 *
 * See the license_msg below and the file COPYING for the software license.
 * See the file algorithm.doc for the compression algorithms and file formats.
 */

#if 0
static char *license_msg[] = {
        "   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 2, 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., 675 Mass Ave, Cambridge, MA 02139, USA.",
        0
};
#endif

#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include "libbb.h"

static FILE *in_file, *out_file;

/* these are freed by gz_close */
static unsigned char *window;
static unsigned long *crc_table = NULL;

static unsigned long crc; /* shift register contents */

/* Return codes from gzip */
static const int ERROR = 1;

/*
 * window size--must be a power of two, and
 *  at least 32K for zip's deflate method 
 */
static const int WSIZE = 0x8000;

/* If BMAX needs to be larger than 16, then h and x[] should be ulg. */
static const int BMAX = 16;             /* maximum bit length of any code (16 for explode) */
static const int N_MAX = 288;           /* maximum number of codes in any set */

static long bytes_out;          /* number of output bytes */
static unsigned long outcnt;    /* bytes in output buffer */

static unsigned hufts;          /* track memory usage */
static unsigned long bb;                        /* bit buffer */
static unsigned bk;             /* bits in bit buffer */

typedef struct huft_s {
        unsigned char e;                /* number of extra bits or operation */
        unsigned char b;                /* number of bits in this code or subcode */
        union {
                unsigned short n;               /* literal, length base, or distance base */
                struct huft_s *t;       /* pointer to next level of table */
        } v;
} huft_t;

static const unsigned short mask_bits[] = {
        0x0000,
        0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
        0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
};

//static int error_number = 0;
/* ========================================================================
 * Signal and error handler.
 */
 
static void abort_gzip()
{
        error_msg("gzip aborted\n");
        exit(ERROR);
}

static void make_crc_table()
{
        unsigned long table_entry;      /* crc shift register */
        unsigned long poly = 0;      /* polynomial exclusive-or pattern */
        int i;                /* counter for all possible eight bit values */
        int k;                /* byte being shifted into crc apparatus */

        /* terms of polynomial defining this crc (except x^32): */
        static int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};

        /* initial shift register value */
        crc = 0xffffffffL;      
        crc_table = (unsigned long *) malloc(256 * sizeof(unsigned long));

        /* Make exclusive-or pattern from polynomial (0xedb88320) */
        for (i = 0; i < sizeof(p)/sizeof(int); i++)
                poly |= 1L << (31 - p[i]);

        /* Compute and print table of CRC's, five per line */
        for (i = 0; i < 256; i++) {
                table_entry = i;
           /* The idea to initialize the register with the byte instead of
             * zero was stolen from Haruhiko Okumura's ar002
             */
                for (k = 8; k; k--) {
                        table_entry = table_entry & 1 ? (table_entry >> 1) ^ poly : table_entry >> 1;
                }
                crc_table[i]=table_entry;
        }
}

/* ===========================================================================
 * Write the output window window[0..outcnt-1] and update crc and bytes_out.
 * (Used for the decompressed data only.)
 */
static void flush_window(void)
{
        int n;

        if (outcnt == 0)
                return;

        for (n = 0; n < outcnt; n++) {
                crc = crc_table[((int) crc ^ (window[n])) & 0xff] ^ (crc >> 8);
        }

        if (fwrite(window, 1, outcnt, out_file) != outcnt) {
                error_msg_and_die("Couldnt write");
        }
        bytes_out += (unsigned long) outcnt;
        outcnt = 0;
}

/*
 * Free the malloc'ed tables built by huft_build(), which makes a linked
 * list of the tables it made, with the links in a dummy first entry of
 * each table. 
 * t: table to free
 */
static int huft_free(huft_t *t)
{
        huft_t *p, *q;

        /* Go through linked list, freeing from the malloced (t[-1]) address. */
        p = t;
        while (p != (huft_t *) NULL) {
                q = (--p)->v.t;
                free((char *) p);
                p = q;
        }
        return 0;
}

/* Given a list of code lengths and a maximum table size, make a set of
 * tables to decode that set of codes.  Return zero on success, one if
 * the given code set is incomplete (the tables are still built in this
 * case), two if the input is invalid (all zero length codes or an
 * oversubscribed set of lengths), and three if not enough memory.
 *
 * b:   code lengths in bits (all assumed <= BMAX)
 * n:   number of codes (assumed <= N_MAX)
 * s:   number of simple-valued codes (0..s-1)
 * d:   list of base values for non-simple codes
 * e:   list of extra bits for non-simple codes
 * t:   result: starting table
 * m:   maximum lookup bits, returns actual
 */
static int huft_build(unsigned int *b, const unsigned int n, const unsigned int s, 
        const unsigned short *d, const unsigned short *e, huft_t **t, int *m)
{
        unsigned a;             /* counter for codes of length k */
        unsigned c[BMAX + 1];   /* bit length count table */
        unsigned f;             /* i repeats in table every f entries */
        int g;                  /* maximum code length */
        int h;                  /* table level */
        register unsigned i;    /* counter, current code */
        register unsigned j;    /* counter */
        register int k;         /* number of bits in current code */
        int l;                  /* bits per table (returned in m) */
        register unsigned *p;           /* pointer into c[], b[], or v[] */
        register huft_t *q;     /* points to current table */
        huft_t r;               /* table entry for structure assignment */
        huft_t *u[BMAX];        /* table stack */
        unsigned v[N_MAX];      /* values in order of bit length */
        register int w;         /* bits before this table == (l * h) */
        unsigned x[BMAX + 1];   /* bit offsets, then code stack */
        unsigned *xp;           /* pointer into x */
        int y;                  /* number of dummy codes added */
        unsigned z;             /* number of entries in current table */

        /* Generate counts for each bit length */
        memset ((void *)(c), 0, sizeof(c));
        p = b;
        i = n;
        do {
                c[*p]++;        /* assume all entries <= BMAX */
                p++;            /* Can't combine with above line (Solaris bug) */
        } while (--i);
        if (c[0] == n) {        /* null input--all zero length codes */
                *t = (huft_t *) NULL;
                *m = 0;
                return 0;
        }

        /* Find minimum and maximum length, bound *m by those */
        l = *m;
        for (j = 1; j <= BMAX; j++)
                if (c[j])
                        break;
        k = j;                          /* minimum code length */
        if ((unsigned) l < j)
                l = j;
        for (i = BMAX; i; i--)
                if (c[i])
                        break;
        g = i;                          /* maximum code length */
        if ((unsigned) l > i)
                l = i;
        *m = l;

        /* Adjust last length count to fill out codes, if needed */
        for (y = 1 << j; j < i; j++, y <<= 1)
                if ((y -= c[j]) < 0)
                        return 2;       /* bad input: more codes than bits */
        if ((y -= c[i]) < 0)
                return 2;
        c[i] += y;

        /* Generate starting offsets into the value table for each length */
        x[1] = j = 0;
        p = c + 1;
        xp = x + 2;
        while (--i) {                   /* note that i == g from above */
                *xp++ = (j += *p++);
        }

        /* Make a table of values in order of bit lengths */
        p = b;
        i = 0;
        do {
                if ((j = *p++) != 0)
                        v[x[j]++] = i;
        } while (++i < n);

        /* Generate the Huffman codes and for each, make the table entries */
        x[0] = i = 0;                   /* first Huffman code is zero */
        p = v;                          /* grab values in bit order */
        h = -1;                         /* no tables yet--level -1 */
        w = -l;                         /* bits decoded == (l * h) */
        u[0] = (huft_t *) NULL; /* just to keep compilers happy */
        q = (huft_t *) NULL;    /* ditto */
        z = 0;                          /* ditto */

        /* go through the bit lengths (k already is bits in shortest code) */
        for (; k <= g; k++) {
                a = c[k];
                while (a--) {
                        /* here i is the Huffman code of length k bits for value *p */
                        /* make tables up to required level */
                        while (k > w + l) {
                                h++;
                                w += l;         /* previous table always l bits */

                                /* compute minimum size table less than or equal to l bits */
                                z = (z = g - w) > (unsigned) l ? l : z; /* upper limit on table size */
                                if ((f = 1 << (j = k - w)) > a + 1) {   /* try a k-w bit table *//* too few codes for k-w bit table */
                                        f -= a + 1;     /* deduct codes from patterns left */
                                        xp = c + k;
                                        while (++j < z) {       /* try smaller tables up to z bits */
                                                if ((f <<= 1) <= *++xp)
                                                        break;  /* enough codes to use up j bits */
                                                f -= *xp;       /* else deduct codes from patterns */
                                        }
                                }
                                z = 1 << j;             /* table entries for j-bit table */

                                /* allocate and link in new table */
                                if ((q = (huft_t *) xmalloc((z + 1) * sizeof(huft_t))) == NULL) {
                                        if (h) {
                                                huft_free(u[0]);
                                        }
                                        return 3;       /* not enough memory */
                                }
                                hufts += z + 1; /* track memory usage */
                                *t = q + 1;             /* link to list for huft_free() */
                                *(t = &(q->v.t)) = NULL;
                                u[h] = ++q;             /* table starts after link */

                                /* connect to last table, if there is one */
                                if (h) {
                                        x[h] = i;       /* save pattern for backing up */
                                        r.b = (unsigned char) l;        /* bits to dump before this table */
                                        r.e = (unsigned char) (16 + j); /* bits in this table */
                                        r.v.t = q;      /* pointer to this table */
                                        j = i >> (w - l);       /* (get around Turbo C bug) */
                                        u[h - 1][j] = r;        /* connect to last table */
                                }
                        }

                        /* set up table entry in r */
                        r.b = (unsigned char) (k - w);
                        if (p >= v + n)
                                r.e = 99;               /* out of values--invalid code */
                        else if (*p < s) {
                                r.e = (unsigned char) (*p < 256 ? 16 : 15);     /* 256 is end-of-block code */
                                r.v.n = (unsigned short) (*p);  /* simple code is just the value */
                                p++;                    /* one compiler does not like *p++ */
                        } else {
                                r.e = (unsigned char) e[*p - s];        /* non-simple--look up in lists */
                                r.v.n = d[*p++ - s];
                        }

                        /* fill code-like entries with r */
                        f = 1 << (k - w);
                        for (j = i >> w; j < z; j += f)
                                q[j] = r;

                        /* backwards increment the k-bit code i */
                        for (j = 1 << (k - 1); i & j; j >>= 1)
                                i ^= j;
                        i ^= j;

                        /* backup over finished tables */
                        while ((i & ((1 << w) - 1)) != x[h]) {
                                h--;                    /* don't need to update q */
                                w -= l;
                        }
                }
        }
        /* Return true (1) if we were given an incomplete table */
        return y != 0 && g != 1;
}

/*
 * inflate (decompress) the codes in a deflated (compressed) block.
 * Return an error code or zero if it all goes ok.
 *
 * tl, td: literal/length and distance decoder tables
 * bl, bd: number of bits decoded by tl[] and td[]
 */
static int inflate_codes(huft_t *tl, huft_t *td, int bl, int bd)
{
        register unsigned long e;               /* table entry flag/number of extra bits */
        unsigned long n, d;                             /* length and index for copy */
        unsigned long w;                                /* current window position */
        huft_t *t;                              /* pointer to table entry */
        unsigned ml, md;                        /* masks for bl and bd bits */
        register unsigned long b;                               /* bit buffer */
        register unsigned k;            /* number of bits in bit buffer */

        /* make local copies of globals */
        b = bb;                                 /* initialize bit buffer */
        k = bk;
        w = outcnt;                             /* initialize window position */

        /* inflate the coded data */
        ml = mask_bits[bl];                     /* precompute masks for speed */
        md = mask_bits[bd];
        for (;;) {                              /* do until end of block */
                while (k < (unsigned) bl) {
                        b |= ((unsigned long)fgetc(in_file)) << k;
                        k += 8;
                }
                if ((e = (t = tl + ((unsigned) b & ml))->e) > 16)
                do {
                        if (e == 99) {
                                return 1;
                        }
                        b >>= t->b;
                        k -= t->b;
                        e -= 16;
                        while (k < e) {
                                b |= ((unsigned long)fgetc(in_file)) << k;
                                k += 8;
                        }
                } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
                b >>= t->b;
                k -= t->b;
                if (e == 16) {          /* then it's a literal */
                        window[w++] = (unsigned char) t->v.n;
                        if (w == WSIZE) {
                                outcnt=(w),
                                flush_window();
                                w = 0;
                        }
                } else {                                /* it's an EOB or a length */

                        /* exit if end of block */
                        if (e == 15) {
                                break;
                        }

                        /* get length of block to copy */
                        while (k < e) {
                                b |= ((unsigned long)fgetc(in_file)) << k;
                                k += 8;
                        }
                        n = t->v.n + ((unsigned) b & mask_bits[e]);
                        b >>= e;
                        k -= e;

                        /* decode distance of block to copy */
                        while (k < (unsigned) bd) {
                                b |= ((unsigned long)fgetc(in_file)) << k;
                                k += 8;
                        }

                        if ((e = (t = td + ((unsigned) b & md))->e) > 16)
                                do {
                                        if (e == 99)
                                                return 1;
                                        b >>= t->b;
                                        k -= t->b;
                                        e -= 16;
                                        while (k < e) {
                                                b |= ((unsigned long)fgetc(in_file)) << k;
                                                k += 8;
                                        }
                                } while ((e = (t = t->v.t + ((unsigned) b & mask_bits[e]))->e) > 16);
                        b >>= t->b;
                        k -= t->b;
                        while (k < e) {
                                b |= ((unsigned long)fgetc(in_file)) << k;
                                k += 8;
                        }
                        d = w - t->v.n - ((unsigned) b & mask_bits[e]);
                        b >>= e;
                        k -= e;

                        /* do the copy */
                        do {
                                n -= (e = (e = WSIZE - ((d &= WSIZE - 1) > w ? d : w)) > n ? n : e);
#if !defined(NOMEMCPY) && !defined(DEBUG)
                                if (w - d >= e) {       /* (this test assumes unsigned comparison) */
                                        memcpy(window + w, window + d, e);
                                        w += e;
                                        d += e;
                                } else                  /* do it slow to avoid memcpy() overlap */
#endif                                                  /* !NOMEMCPY */
                                        do {
                                                window[w++] = window[d++];
                                        } while (--e);
                                if (w == WSIZE) {
                                        outcnt=(w),
                                        flush_window();
                                        w = 0;
                                }
                        } while (n);
                }
        }

        /* restore the globals from the locals */
        outcnt = w;                     /* restore global window pointer */
        bb = b;                         /* restore global bit buffer */
        bk = k;

        /* done */
        return 0;
}

/*
 * decompress an inflated block
 * e: last block flag
 *
 * GLOBAL VARIABLES: bb, kk,
 */
static int inflate_block(int *e)
{
        unsigned t;                     /* block type */
        register unsigned long b;                       /* bit buffer */
        register unsigned k;            /* number of bits in bit buffer */
        static unsigned short cplens[] = {              /* Copy lengths for literal codes 257..285 */
                3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
                35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0
        };
        /* note: see note #13 above about the 258 in this list. */
        static unsigned short cplext[] = {              /* Extra bits for literal codes 257..285 */
                0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
                3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99
        };                              /* 99==invalid */
        static unsigned short cpdist[] = {              /* Copy offsets for distance codes 0..29 */
                1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
                257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
                8193, 12289, 16385, 24577
        };
        static unsigned short cpdext[] = {              /* Extra bits for distance codes */
                0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
                7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
                12, 12, 13, 13
        };

        /* make local bit buffer */
        b = bb;
        k = bk;

        /* read in last block bit */
        while (k < 1) {
                b |= ((unsigned long)fgetc(in_file)) << k;
                k += 8;
        }
        *e = (int) b & 1;
        b >>= 1;
        k -= 1;

        /* read in block type */
        while (k < 2) {
                b |= ((unsigned long)fgetc(in_file)) << k;
                k += 8;
        }
        t = (unsigned) b & 3;
        b >>= 2;
        k -= 2;

        /* restore the global bit buffer */
        bb = b;
        bk = k;

        /* inflate that block type */
        switch (t) {
        case 0: /* Inflate stored */
                {
                        unsigned long n;                        /* number of bytes in block */
                        unsigned long w;                        /* current window position */
                        register unsigned long b_stored;                        /* bit buffer */
                        register unsigned long k_stored;                /* number of bits in bit buffer */

                        /* make local copies of globals */
                        b_stored = bb;                          /* initialize bit buffer */
                        k_stored = bk;
                        w = outcnt;                     /* initialize window position */

                        /* go to byte boundary */
                        n = k_stored & 7;
                        b_stored >>= n;
                        k_stored -= n;

                        /* get the length and its complement */
                        while (k_stored < 16) {
                                b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
                                k_stored += 8;
                        }
                        n = ((unsigned) b_stored & 0xffff);
                        b_stored >>= 16;
                        k_stored -= 16;
                        while (k_stored < 16) {
                                b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
                                k_stored += 8;
                        }
                        if (n != (unsigned) ((~b_stored) & 0xffff)) {
                                return 1;               /* error in compressed data */
                        }
                        b_stored >>= 16;
                        k_stored -= 16;

                        /* read and output the compressed data */
                        while (n--) {
                                while (k_stored < 8) {
                                        b_stored |= ((unsigned long)fgetc(in_file)) << k_stored;
                                        k_stored += 8;
                                }
                                window[w++] = (unsigned char) b_stored;
                                if (w == (unsigned long)WSIZE) {
                                        outcnt=(w),
                                        flush_window();
                                        w = 0;
                                }
                                b_stored >>= 8;
                                k_stored -= 8;
                        }

                        /* restore the globals from the locals */
                        outcnt = w;                     /* restore global window pointer */
                        bb = b_stored;                          /* restore global bit buffer */
                        bk = k_stored;
                        return 0;
                }
        case 1: /* Inflate fixed 
                         * decompress an inflated type 1 (fixed Huffman codes) block.  We should
                         * either replace this with a custom decoder, or at least precompute the
                         * Huffman tables.
                         */
                {
                        int i;                                  /* temporary variable */
                        huft_t *tl;                             /* literal/length code table */
                        huft_t *td;                             /* distance code table */
                        int bl;                                 /* lookup bits for tl */
                        int bd;                                 /* lookup bits for td */
                        unsigned int l[288];    /* length list for huft_build */

                        /* set up literal table */
                        for (i = 0; i < 144; i++) {
                                l[i] = 8;
                        }
                        for (; i < 256; i++) {
                                l[i] = 9;
                        }
                        for (; i < 280; i++) {
                                l[i] = 7;
                        }
                        for (; i < 288; i++) {  /* make a complete, but wrong code set */
                                l[i] = 8;
                        }
                        bl = 7;
                        if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) {
                                return i;
                        }

                        /* set up distance table */
                        for (i = 0; i < 30; i++) {      /* make an incomplete code set */
                                l[i] = 5;
                        }
                        bd = 5;
                        if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) {
                                huft_free(tl);
                                return i;
                        }

                        /* decompress until an end-of-block code */
                        if (inflate_codes(tl, td, bl, bd))
                                return 1;

                        /* free the decoding tables, return */
                        huft_free(tl);
                        huft_free(td);
                        return 0;
                }
        case 2: /* Inflate dynamic */
                {
                        /* Tables for deflate from PKZIP's appnote.txt. */
                        static unsigned border[] = {    /* Order of the bit length code lengths */
                                16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
                        };
                        int dbits = 6;                                  /* bits in base distance lookup table */
                        int lbits = 9;                                  /* bits in base literal/length lookup table */

                        int i;                                          /* temporary variables */
                        unsigned j;
                        unsigned l;                                     /* last length */
                        unsigned m;                                     /* mask for bit lengths table */
                        unsigned n;                                     /* number of lengths to get */
                        huft_t *tl;                     /* literal/length code table */
                        huft_t *td;                     /* distance code table */
                        int bl;                                         /* lookup bits for tl */
                        int bd;                                         /* lookup bits for td */
                        unsigned nb;                            /* number of bit length codes */
                        unsigned nl;                            /* number of literal/length codes */
                        unsigned nd;                            /* number of distance codes */

                        unsigned ll[286 + 30];          /* literal/length and distance code lengths */
                        register unsigned long b_dynamic;       /* bit buffer */
                        register unsigned k_dynamic;            /* number of bits in bit buffer */

                        /* make local bit buffer */
                        b_dynamic = bb;
                        k_dynamic = bk;

                        /* read in table lengths */
                        while (k_dynamic < 5) {
                                b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
                                k_dynamic += 8;
                        }
                        nl = 257 + ((unsigned) b_dynamic & 0x1f);       /* number of literal/length codes */
                        b_dynamic >>= 5;
                        k_dynamic -= 5;
                        while (k_dynamic < 5) {
                                b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
                                k_dynamic += 8;
                        }
                        nd = 1 + ((unsigned) b_dynamic & 0x1f); /* number of distance codes */
                        b_dynamic >>= 5;
                        k_dynamic -= 5;
                        while (k_dynamic < 4) {
                                b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
                                k_dynamic += 8;
                        }
                        nb = 4 + ((unsigned) b_dynamic & 0xf);  /* number of bit length codes */
                        b_dynamic >>= 4;
                        k_dynamic -= 4;
                        if (nl > 286 || nd > 30) {
                                return 1;       /* bad lengths */
                        }

                        /* read in bit-length-code lengths */
                        for (j = 0; j < nb; j++) {
                                while (k_dynamic < 3) {
                                        b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
                                        k_dynamic += 8;
                                }
                                ll[border[j]] = (unsigned) b_dynamic & 7;
                                b_dynamic >>= 3;
                                k_dynamic -= 3;
                        }
                        for (; j < 19; j++) {
                                ll[border[j]] = 0;
                        }

                        /* build decoding table for trees--single level, 7 bit lookup */
                        bl = 7;
                        if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) {
                                if (i == 1) {
                                        huft_free(tl);
                                }
                                return i;                       /* incomplete code set */
                        }

                        /* read in literal and distance code lengths */
                        n = nl + nd;
                        m = mask_bits[bl];
                        i = l = 0;
                        while ((unsigned) i < n) {
                                while (k_dynamic < (unsigned) bl) {
                                        b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
                                        k_dynamic += 8;
                                }
                                j = (td = tl + ((unsigned) b_dynamic & m))->b;
                                b_dynamic >>= j;
                                k_dynamic -= j;
                                j = td->v.n;
                                if (j < 16) {                   /* length of code in bits (0..15) */
                                        ll[i++] = l = j;        /* save last length in l */
                                }
                                else if (j == 16) {             /* repeat last length 3 to 6 times */
                                        while (k_dynamic < 2) {
                                                b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
                                                k_dynamic += 8;
                                        }
                                        j = 3 + ((unsigned) b_dynamic & 3);
                                        b_dynamic >>= 2;
                                        k_dynamic -= 2;
                                        if ((unsigned) i + j > n) {
                                                return 1;
                                        }
                                        while (j--) {
                                                ll[i++] = l;
                                        }
                                } else if (j == 17) {   /* 3 to 10 zero length codes */
                                        while (k_dynamic < 3) {
                                                b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
                                                k_dynamic += 8;
                                        }
                                        j = 3 + ((unsigned) b_dynamic & 7);
                                        b_dynamic >>= 3;
                                        k_dynamic -= 3;
                                        if ((unsigned) i + j > n) {
                                                return 1;
                                        }
                                        while (j--) {
                                                ll[i++] = 0;
                                        }
                                        l = 0;
                                } else {                /* j == 18: 11 to 138 zero length codes */
                                        while (k_dynamic < 7) {
                                                b_dynamic |= ((unsigned long)fgetc(in_file)) << k_dynamic;
                                                k_dynamic += 8;
                                        }
                                        j = 11 + ((unsigned) b_dynamic & 0x7f);
                                        b_dynamic >>= 7;
                                        k_dynamic -= 7;
                                        if ((unsigned) i + j > n) {
                                                return 1;
                                        }
                                        while (j--) {
                                                ll[i++] = 0;
                                        }
                                        l = 0;
                                }
                        }

                        /* free decoding table for trees */
                        huft_free(tl);

                        /* restore the global bit buffer */
                        bb = b_dynamic;
                        bk = k_dynamic;

                        /* build the decoding tables for literal/length and distance codes */
                        bl = lbits;
                        if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) {
                                if (i == 1) {
                                        error_msg("Incomplete literal tree");
                                        huft_free(tl);
                                }
                                return i;                       /* incomplete code set */
                        }
                        bd = dbits;
                        if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) {
                                if (i == 1) {
                                        error_msg("incomplete distance tree");
                                        huft_free(td);
                                }
                                huft_free(tl);
                                return i;                       /* incomplete code set */
                        }

                        /* decompress until an end-of-block code */
                        if (inflate_codes(tl, td, bl, bd))
                                return 1;

                        /* free the decoding tables, return */
                        huft_free(tl);
                        huft_free(td);
                        return 0;
                }
        default:
                /* bad block type */
                return 2;
        }
}

/*
 * decompress an inflated entry
 *
 * GLOBAL VARIABLES: outcnt, bk, bb, hufts, inptr
 */
static int inflate()
{
        int e;                          /* last block flag */
        int r;                          /* result code */
        unsigned h = 0;         /* maximum struct huft's malloc'ed */

        /* initialize window, bit buffer */
        outcnt = 0;
        bk = 0;
        bb = 0;

        /* decompress until the last block */
        do {
                hufts = 0;
                if ((r = inflate_block(&e)) != 0) {
                        return r;
                }
                if (hufts > h) {
                        h = hufts;
                }
        } while (!e);

        /* Undo too much lookahead.  The next read will be byte aligned so we
         * can discard unused bits in the last meaningful byte.  */
        while (bk >= 8) {
                bk -= 8;
                ungetc((bb << bk), in_file);
        }

        /* flush out window */
        flush_window();

        /* return success */
        return 0;
}

/* ===========================================================================
 * 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.
 * in, out: input and output file descriptors
 */
extern int unzip(FILE *l_in_file, FILE *l_out_file)
{
        const int extra_field = 0x04;   /* bit 2 set: extra field present */
        const int orig_name = 0x08;     /* bit 3 set: original file name present */
        const int comment = 0x10;       /* bit 4 set: file comment present */
        unsigned char buf[8];   /* extended local header */
        unsigned char flags;    /* compression flags */
        char magic[2];                  /* magic header */
        int method;
        typedef void (*sig_type) (int);
        int exit_code=0;        /* program exit code */
        int i;

        in_file = l_in_file;
        out_file = l_out_file;

        if (signal(SIGINT, SIG_IGN) != SIG_IGN) {
                (void) signal(SIGINT, (sig_type) abort_gzip);
        }
#ifdef SIGTERM
//      if (signal(SIGTERM, SIG_IGN) != SIG_IGN) {
//              (void) signal(SIGTERM, (sig_type) abort_gzip);
//      }
#endif
#ifdef SIGHUP
        if (signal(SIGHUP, SIG_IGN) != SIG_IGN) {
                (void) signal(SIGHUP, (sig_type) abort_gzip);
        }
#endif

        /* Allocate all global buffers (for DYN_ALLOC option) */
        window = xmalloc((size_t)(((2L*WSIZE)+1L)*sizeof(unsigned char)));
        outcnt = 0;
        bytes_out = 0L;

        magic[0] = fgetc(in_file);
        magic[1] = fgetc(in_file);

        /* Magic header for gzip files, 1F 8B = \037\213 */
        if (memcmp(magic, "\037\213", 2) != 0) {
                error_msg("Invalid gzip magic");
                return EXIT_FAILURE;
        }

        method = (int) fgetc(in_file);
        if (method != 8) {
                error_msg("unknown method %d -- get newer version of gzip", method);
                exit_code = 1;
                return -1;
        }

        flags = (unsigned char) fgetc(in_file);

        /* Ignore time stamp(4), extra flags(1), OS type(1) */
        for (i = 0; i < 6; i++)
                fgetc(in_file);

        if ((flags & extra_field) != 0) {
                size_t extra;
                extra = fgetc(in_file);
                extra += fgetc(in_file) << 8;

                for (i = 0; i < extra; i++)
                        fgetc(in_file);
        }

        /* Discard original name if any */
        if ((flags & orig_name) != 0) {
                while (fgetc(in_file) != 0);    /* null */
        }

        /* Discard file comment if any */
        if ((flags & comment) != 0) {
                while (fgetc(in_file) != 0);    /* null */
        }

        if (method < 0) {
                printf("it failed\n");
                return(exit_code);              /* error message already emitted */
        }

        make_crc_table();

        /* Decompress */
        if (method == 8) {

                int res = inflate();

                if (res == 3) {
                        error_msg(memory_exhausted);
                        exit_code = 1;
                } else if (res != 0) {
                        error_msg("invalid compressed data--format violated");
                        exit_code = 1;
                }

        } else {
                error_msg("internal error, invalid method");
                exit_code = 1;
        }

        /* Get the crc and original length
         * crc32  (see algorithm.doc)
         * uncompressed input size modulo 2^32
         */
        fread(buf, 1, 8, in_file);

        /* Validate decompression - crc */
        if (!exit_code && (unsigned int)((buf[0] | (buf[1] << 8)) |((buf[2] | (buf[3] << 8)) << 16)) != (crc ^ 0xffffffffL)) {
                error_msg("invalid compressed data--crc error");
                exit_code = 1;
        }
        /* Validate decompression - size */
        if (!exit_code && ((buf[4] | (buf[5] << 8)) |((buf[6] | (buf[7] << 8)) << 16)) != (unsigned long) bytes_out) {
                error_msg("invalid compressed data--length error");
                exit_code = 1;
        }

        free(window);
        free(crc_table);

        window = NULL;
        crc_table = NULL;

        return exit_code;
}

/*
 * This needs access to global variables wondow and crc_table, so its not in its own file.
 */
extern void gz_close(int gunzip_pid)
{
        if (kill(gunzip_pid, SIGTERM) == -1) {
                error_msg_and_die("***  Couldnt kill old gunzip process *** aborting");
        }

        if (waitpid(gunzip_pid, NULL, 0) == -1) {
                printf("Couldnt wait ?");
        }
                free(window);
                free(crc_table);
}