minix/sys/lib/libsa/cread.c

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/* $NetBSD: cread.c,v 1.26 2013/10/13 20:09:02 joerg Exp $ */
/*
* Copyright (c) 1996
* Matthias Drochner. 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 ``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 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.
*
*/
/*
* Support for compressed bootfiles (only read)
*
* - replaces open(), close(), read(), lseek().
* - original libsa open(), close(), read(), lseek() are called
* as oopen(), oclose(), oread() resp. olseek().
* - compression parts stripped from zlib:gzio.c
*/
/* gzio.c -- IO on .gz files
* Copyright (C) 1995-1996 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "stand.h"
#ifdef _STANDALONE
#include <lib/libkern/libkern.h>
#include <lib/libz/libz.h>
#else
#include <string.h>
#include <zlib.h>
#endif
#define EOF (-1) /* needed by compression code */
#ifdef SAVE_MEMORY
#define Z_BUFSIZE 1024
#else
#define Z_BUFSIZE 4096
#endif
static const 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 struct sd {
z_stream stream;
int z_err; /* error code for last stream operation */
int z_eof; /* set if end of input file */
int fd;
unsigned char *inbuf; /* input buffer */
unsigned long crc; /* crc32 of uncompressed data */
int compressed; /* 1 if input file is a .gz file */
} *ss[SOPEN_MAX];
static int get_byte(struct sd *);
static unsigned long getLong(struct sd *);
static void check_header(struct sd *);
/* XXX - find suitable header file for these: */
void *zcalloc(void *, unsigned int, unsigned int);
void zcfree(void *, void *);
void zmemcpy(unsigned char *, unsigned char *, unsigned int);
/*
* The libkern version of this function uses an 8K set of tables.
* This is the double-loop version of LE CRC32 from if_ethersubr,
* lightly modified -- it is 200 bytes smaller than the version using
* a 4-bit table and at least 8K smaller than the libkern version.
*/
#ifndef ETHER_CRC_POLY_LE
#define ETHER_CRC_POLY_LE 0xedb88320
#endif
uint32_t
crc32(uint32_t crc, const uint8_t *const buf, size_t len)
{
uint32_t c, carry;
size_t i, j;
crc = 0xffffffffU ^ crc;
for (i = 0; i < len; i++) {
c = buf[i];
for (j = 0; j < 8; j++) {
carry = ((crc & 0x01) ? 1 : 0) ^ (c & 0x01);
crc >>= 1;
c >>= 1;
if (carry) {
crc = (crc ^ ETHER_CRC_POLY_LE);
}
}
}
return (crc ^ 0xffffffffU);
}
/*
* compression utilities
*/
void *
zcalloc(void *opaque, unsigned int items, unsigned int size)
{
return alloc(items * size);
}
void
zcfree(void *opaque, void *ptr)
{
dealloc(ptr, 0); /* XXX works only with modified allocator */
}
void
zmemcpy(unsigned char *dest, unsigned char *source, unsigned int len)
{
memcpy(dest, source, len);
}
static int
get_byte(struct sd *s)
{
if (s->z_eof)
return EOF;
if (s->stream.avail_in == 0) {
int got;
errno = 0;
got = oread(s->fd, s->inbuf, Z_BUFSIZE);
if (got <= 0) {
s->z_eof = 1;
if (errno)
s->z_err = Z_ERRNO;
return EOF;
}
s->stream.avail_in = got;
s->stream.next_in = s->inbuf;
}
s->stream.avail_in--;
return *(s->stream.next_in)++;
}
static unsigned long
getLong(struct sd *s)
{
unsigned long x;
int c;
x = (unsigned long)get_byte(s);
x += ((unsigned long)get_byte(s)) << 8;
x += ((unsigned long)get_byte(s)) << 16;
c = get_byte(s);
if (c == EOF)
s->z_err = Z_DATA_ERROR;
x += ((unsigned long)c) << 24;
return x;
}
static void
check_header(struct sd *s)
{
int method; /* method byte */
int flags; /* flags byte */
unsigned int len;
int c;
/* Check the gzip magic header */
for (len = 0; len < 2; len++) {
c = get_byte(s);
if (c == gz_magic[len])
continue;
if ((c == EOF) && (len == 0)) {
/*
* We must not change s->compressed if we are at EOF;
* we may have come to the end of a gzipped file and be
* check to see if another gzipped file is concatenated
* to this one. If one isn't, we still need to be able
* to lseek on this file as a compressed file.
*/
return;
}
s->compressed = 0;
if (c != EOF) {
s->stream.avail_in++;
s->stream.next_in--;
}
s->z_err = s->stream.avail_in != 0 ? Z_OK : Z_STREAM_END;
return;
}
s->compressed = 1;
method = get_byte(s);
flags = get_byte(s);
if (method != Z_DEFLATED || (flags & RESERVED) != 0) {
s->z_err = Z_DATA_ERROR;
return;
}
/* Discard time, xflags and OS code: */
for (len = 0; len < 6; len++)
(void)get_byte(s);
if ((flags & EXTRA_FIELD) != 0) {
/* skip the extra field */
len = (unsigned int)get_byte(s);
len += ((unsigned int)get_byte(s)) << 8;
/* len is garbage if EOF but the loop below will quit anyway */
while (len-- != 0 && get_byte(s) != EOF)
/*void*/;
}
if ((flags & ORIG_NAME) != 0) {
/* skip the original file name */
while ((c = get_byte(s)) != 0 && c != EOF)
/*void*/;
}
if ((flags & COMMENT) != 0) {
/* skip the .gz file comment */
while ((c = get_byte(s)) != 0 && c != EOF)
/*void*/;
}
if ((flags & HEAD_CRC) != 0) { /* skip the header crc */
for (len = 0; len < 2; len++)
(void)get_byte(s);
}
s->z_err = s->z_eof ? Z_DATA_ERROR : Z_OK;
}
/*
* new open(), close(), read(), lseek()
*/
int
open(const char *fname, int mode)
{
int fd;
struct sd *s = 0;
if (((fd = oopen(fname, mode)) == -1) || (mode != 0))
/* compression only for read */
return fd;
ss[fd] = s = alloc(sizeof(struct sd));
if (s == 0)
goto errout;
(void)memset(s, 0, sizeof(struct sd));
if (inflateInit2(&(s->stream), -15) != Z_OK)
goto errout;
s->stream.next_in = s->inbuf = (unsigned char *)alloc(Z_BUFSIZE);
if (s->inbuf == 0) {
inflateEnd(&(s->stream));
goto errout;
}
s->fd = fd;
check_header(s); /* skip the .gz header */
return fd;
errout:
if (s != 0)
dealloc(s, sizeof(struct sd));
ss[fd] = NULL;
oclose(fd);
return -1;
}
int
close(int fd)
{
struct sd *s;
#if !defined(LIBSA_NO_FD_CHECKING)
if ((unsigned int)fd >= SOPEN_MAX) {
errno = EBADF;
return -1;
}
#endif
s = ss[fd];
if (s != NULL) {
inflateEnd(&(s->stream));
dealloc(s->inbuf, Z_BUFSIZE);
dealloc(s, sizeof(struct sd));
}
return oclose(fd);
}
ssize_t
read(int fd, void *buf, size_t len)
{
struct sd *s;
unsigned char *start = buf; /* starting point for crc computation */
s = ss[fd];
if (s->z_err == Z_DATA_ERROR || s->z_err == Z_ERRNO)
return -1;
if (s->z_err == Z_STREAM_END)
return 0; /* EOF */
s->stream.next_out = buf;
s->stream.avail_out = len;
while (s->stream.avail_out != 0) {
if (s->compressed == 0) {
/* Copy first the lookahead bytes: */
unsigned int n = s->stream.avail_in;
if (n > s->stream.avail_out)
n = s->stream.avail_out;
if (n > 0) {
zmemcpy(s->stream.next_out,
s->stream.next_in, n);
s->stream.next_out += n;
s->stream.next_in += n;
s->stream.avail_out -= n;
s->stream.avail_in -= n;
}
if (s->stream.avail_out > 0) {
int got;
got = oread(s->fd, s->stream.next_out,
s->stream.avail_out);
if (got == -1)
return got;
s->stream.avail_out -= got;
}
return (int)(len - s->stream.avail_out);
}
if (s->stream.avail_in == 0 && !s->z_eof) {
int got;
errno = 0;
got = oread(fd, s->inbuf, Z_BUFSIZE);
if (got <= 0) {
s->z_eof = 1;
if (errno) {
s->z_err = Z_ERRNO;
break;
}
}
s->stream.avail_in = got;
s->stream.next_in = s->inbuf;
}
s->z_err = inflate(&(s->stream), Z_NO_FLUSH);
if (s->z_err == Z_STREAM_END) {
/* Check CRC and original size */
s->crc = crc32(s->crc, start, (unsigned int)
(s->stream.next_out - start));
start = s->stream.next_out;
if (getLong(s) != s->crc ||
getLong(s) != s->stream.total_out) {
s->z_err = Z_DATA_ERROR;
} else {
/* Check for concatenated .gz files: */
check_header(s);
if (s->z_err == Z_OK) {
inflateReset(&(s->stream));
s->crc = crc32(0L, Z_NULL, 0);
}
}
}
if (s->z_err != Z_OK || s->z_eof)
break;
}
s->crc = crc32(s->crc, start,
(unsigned int)(s->stream.next_out - start));
return (int)(len - s->stream.avail_out);
}
off_t
lseek(int fd, off_t offset, int where)
{
struct open_file *f;
struct sd *s;
#if !defined(LIBSA_NO_FD_CHECKING)
if ((unsigned int)fd >= SOPEN_MAX) {
errno = EBADF;
return -1;
}
#endif
f = &files[fd];
if ((f->f_flags & F_READ) == 0)
return olseek(fd, offset, where);
s = ss[fd];
if(s->compressed == 0) {
off_t res = olseek(fd, offset, where);
if (res != (off_t)-1) {
/* make sure the lookahead buffer is invalid */
s->stream.avail_in = 0;
}
return res;
}
switch(where) {
case SEEK_CUR:
offset += s->stream.total_out;
case SEEK_SET:
/* if seek backwards, simply start from the beginning */
if (offset < s->stream.total_out) {
off_t res;
void *sav_inbuf;
res = olseek(fd, 0, SEEK_SET);
if(res == (off_t)-1)
return res;
/* ??? perhaps fallback to close / open */
inflateEnd(&(s->stream));
sav_inbuf = s->inbuf; /* don't allocate again */
(void)memset(s, 0, sizeof(struct sd));
/* this resets total_out to 0! */
inflateInit2(&(s->stream), -15);
s->stream.next_in = s->inbuf = sav_inbuf;
s->fd = fd;
check_header(s); /* skip the .gz header */
}
/* to seek forwards, throw away data */
if (offset > s->stream.total_out) {
off_t toskip = offset - s->stream.total_out;
while (toskip > 0) {
#define DUMMYBUFSIZE 256
char dummybuf[DUMMYBUFSIZE];
off_t len = toskip;
if (len > DUMMYBUFSIZE)
len = DUMMYBUFSIZE;
if (read(fd, dummybuf, len) != len) {
errno = EOFFSET;
return (off_t)-1;
}
toskip -= len;
}
}
#ifdef DEBUG
if (offset != s->stream.total_out)
panic("lseek compressed");
#endif
return offset;
case SEEK_END:
errno = EOFFSET;
break;
default:
errno = EINVAL;
break;
}
return (off_t)-1;
}