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/**
* xzlib.c: front end for the transparent suport of lzma compression
* at the I/O layer, based on an example file from lzma project
*
* See Copyright for the status of this software.
*
* Anders F Bjorklund <afb@users.sourceforge.net>
*/
#define IN_LIBXML
#include "libxml.h"
#ifdef HAVE_LZMA_H
#include <string.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_ZLIB_H
#include <zlib.h>
#endif
#include <lzma.h>
#include "xzlib.h"
/* values for xz_state how */
#define LOOK 0 /* look for a gzip/lzma header */
#define COPY 1 /* copy input directly */
#define GZIP 2 /* decompress a gzip stream */
#define LZMA 3 /* decompress a lzma stream */
/* internal lzma file state data structure */
typedef struct {
int mode; /* see lzma modes above */
int fd; /* file descriptor */
char *path; /* path or fd for error messages */
uint64_t pos; /* current position in uncompressed data */
unsigned int size; /* buffer size, zero if not allocated yet */
unsigned int want; /* requested buffer size, default is BUFSIZ */
unsigned char *in; /* input buffer */
unsigned char *out; /* output buffer (double-sized when reading) */
unsigned char *next; /* next output data to deliver or write */
unsigned int have; /* amount of output data unused at next */
int eof; /* true if end of input file reached */
uint64_t start; /* where the lzma data started, for rewinding */
uint64_t raw; /* where the raw data started, for seeking */
int how; /* 0: get header, 1: copy, 2: decompress */
int direct; /* true if last read direct, false if lzma */
/* seek request */
uint64_t skip; /* amount to skip (already rewound if backwards) */
int seek; /* true if seek request pending */
/* error information */
int err; /* error code */
char *msg; /* error message */
/* lzma stream */
lzma_stream strm; /* stream structure in-place (not a pointer) */
char padding1[32]; /* padding allowing to cope with possible
extensions of above structure without
too much side effect */
#ifdef HAVE_ZLIB_H
/* zlib inflate or deflate stream */
z_stream zstrm; /* stream structure in-place (not a pointer) */
#endif
char padding2[32]; /* padding allowing to cope with possible
extensions of above structure without
too much side effect */
} xz_state, *xz_statep;
static void
xz_error(xz_statep state, int err, const char *msg)
{
/* free previously allocated message and clear */
if (state->msg != NULL) {
if (state->err != LZMA_MEM_ERROR)
free(state->msg);
state->msg = NULL;
}
/* set error code, and if no message, then done */
state->err = err;
if (msg == NULL)
return;
/* for an out of memory error, save as static string */
if (err == LZMA_MEM_ERROR) {
state->msg = (char *) msg;
return;
}
/* construct error message with path */
if ((state->msg =
malloc(strlen(state->path) + strlen(msg) + 3)) == NULL) {
state->err = LZMA_MEM_ERROR;
state->msg = (char *) "out of memory";
return;
}
strcpy(state->msg, state->path);
strcat(state->msg, ": ");
strcat(state->msg, msg);
return;
}
static void
xz_reset(xz_statep state)
{
state->have = 0; /* no output data available */
state->eof = 0; /* not at end of file */
state->how = LOOK; /* look for gzip header */
state->direct = 1; /* default for empty file */
state->seek = 0; /* no seek request pending */
xz_error(state, LZMA_OK, NULL); /* clear error */
state->pos = 0; /* no uncompressed data yet */
state->strm.avail_in = 0; /* no input data yet */
#ifdef HAVE_ZLIB_H
state->zstrm.avail_in = 0; /* no input data yet */
#endif
}
static xzFile
xz_open(const char *path, int fd, const char *mode ATTRIBUTE_UNUSED)
{
xz_statep state;
/* allocate xzFile structure to return */
state = malloc(sizeof(xz_state));
if (state == NULL)
return NULL;
state->size = 0; /* no buffers allocated yet */
state->want = BUFSIZ; /* requested buffer size */
state->msg = NULL; /* no error message yet */
/* save the path name for error messages */
state->path = malloc(strlen(path) + 1);
if (state->path == NULL) {
free(state);
return NULL;
}
strcpy(state->path, path);
/* open the file with the appropriate mode (or just use fd) */
state->fd = fd != -1 ? fd : open(path,
#ifdef O_LARGEFILE
O_LARGEFILE |
#endif
#ifdef O_BINARY
O_BINARY |
#endif
O_RDONLY, 0666);
if (state->fd == -1) {
free(state->path);
free(state);
return NULL;
}
/* save the current position for rewinding (only if reading) */
state->start = lseek(state->fd, 0, SEEK_CUR);
if (state->start == (uint64_t) - 1)
state->start = 0;
/* initialize stream */
xz_reset(state);
/* return stream */
return (xzFile) state;
}
xzFile
__libxml2_xzopen(const char *path, const char *mode)
{
return xz_open(path, -1, mode);
}
xzFile
__libxml2_xzdopen(int fd, const char *mode)
{
char *path; /* identifier for error messages */
xzFile xz;
if (fd == -1 || (path = malloc(7 + 3 * sizeof(int))) == NULL)
return NULL;
sprintf(path, "<fd:%d>", fd); /* for debugging */
xz = xz_open(path, fd, mode);
free(path);
return xz;
}
static int
xz_load(xz_statep state, unsigned char *buf, unsigned int len,
unsigned int *have)
{
int ret;
*have = 0;
do {
ret = read(state->fd, buf + *have, len - *have);
if (ret <= 0)
break;
*have += ret;
} while (*have < len);
if (ret < 0) {
xz_error(state, -1, strerror(errno));
return -1;
}
if (ret == 0)
state->eof = 1;
return 0;
}
static int
xz_avail(xz_statep state)
{
lzma_stream *strm = &(state->strm);
if (state->err != LZMA_OK)
return -1;
if (state->eof == 0) {
/* avail_in is size_t, which is not necessary sizeof(unsigned) */
unsigned tmp = strm->avail_in;
if (xz_load(state, state->in, state->size, &tmp) == -1) {
strm->avail_in = tmp;
return -1;
}
strm->avail_in = tmp;
strm->next_in = state->in;
}
return 0;
}
static int
is_format_xz(xz_statep state)
{
lzma_stream *strm = &(state->strm);
return strm->avail_in >= 6 && memcmp(state->in, "\3757zXZ", 6) == 0;
}
static int
is_format_lzma(xz_statep state)
{
lzma_stream *strm = &(state->strm);
lzma_filter filter;
lzma_options_lzma *opt;
uint32_t dict_size;
uint64_t uncompressed_size;
size_t i;
if (strm->avail_in < 13)
return 0;
filter.id = LZMA_FILTER_LZMA1;
if (lzma_properties_decode(&filter, NULL, state->in, 5) != LZMA_OK)
return 0;
opt = filter.options;
dict_size = opt->dict_size;
free(opt);
/* A hack to ditch tons of false positives: We allow only dictionary
* sizes that are 2^n or 2^n + 2^(n-1) or UINT32_MAX. LZMA_Alone
* created only files with 2^n, but accepts any dictionary size.
* If someone complains, this will be reconsidered.
*/
if (dict_size != UINT32_MAX) {
uint32_t d = dict_size - 1;
d |= d >> 2;
d |= d >> 3;
d |= d >> 4;
d |= d >> 8;
d |= d >> 16;
++d;
if (d != dict_size || dict_size == 0)
return 0;
}
/* Another hack to ditch false positives: Assume that if the
* uncompressed size is known, it must be less than 256 GiB.
* Again, if someone complains, this will be reconsidered.
*/
uncompressed_size = 0;
for (i = 0; i < 8; ++i)
uncompressed_size |= (uint64_t) (state->in[5 + i]) << (i * 8);
if (uncompressed_size != UINT64_MAX
&& uncompressed_size > (UINT64_C(1) << 38))
return 0;
return 1;
}
#ifdef HAVE_ZLIB_H
/* Get next byte from input, or -1 if end or error. */
#define NEXT() ((strm->avail_in == 0 && xz_avail(state) == -1) ? -1 : \
(strm->avail_in == 0 ? -1 : \
(strm->avail_in--, *(strm->next_in)++)))
/* Get a four-byte little-endian integer and return 0 on success and the value
in *ret. Otherwise -1 is returned and *ret is not modified. */
static int
gz_next4(xz_statep state, unsigned long *ret)
{
int ch;
unsigned long val;
z_streamp strm = &(state->zstrm);
val = NEXT();
val += (unsigned) NEXT() << 8;
val += (unsigned long) NEXT() << 16;
ch = NEXT();
if (ch == -1)
return -1;
val += (unsigned long) ch << 24;
*ret = val;
return 0;
}
#endif
static int
xz_head(xz_statep state)
{
lzma_stream *strm = &(state->strm);
lzma_stream init = LZMA_STREAM_INIT;
int flags;
unsigned len;
/* allocate read buffers and inflate memory */
if (state->size == 0) {
/* allocate buffers */
state->in = malloc(state->want);
state->out = malloc(state->want << 1);
if (state->in == NULL || state->out == NULL) {
if (state->out != NULL)
free(state->out);
if (state->in != NULL)
free(state->in);
xz_error(state, LZMA_MEM_ERROR, "out of memory");
return -1;
}
state->size = state->want;
/* allocate decoder memory */
state->strm = init;
state->strm.avail_in = 0;
state->strm.next_in = NULL;
if (lzma_auto_decoder(&state->strm, UINT64_MAX, 0) != LZMA_OK) {
free(state->out);
free(state->in);
state->size = 0;
xz_error(state, LZMA_MEM_ERROR, "out of memory");
return -1;
}
#ifdef HAVE_ZLIB_H
/* allocate inflate memory */
state->zstrm.zalloc = Z_NULL;
state->zstrm.zfree = Z_NULL;
state->zstrm.opaque = Z_NULL;
state->zstrm.avail_in = 0;
state->zstrm.next_in = Z_NULL;
if (inflateInit2(&(state->zstrm), -15) != Z_OK) { /* raw inflate */
free(state->out);
free(state->in);
state->size = 0;
xz_error(state, LZMA_MEM_ERROR, "out of memory");
return -1;
}
#endif
}
/* get some data in the input buffer */
if (strm->avail_in == 0) {
if (xz_avail(state) == -1)
return -1;
if (strm->avail_in == 0)
return 0;
}
/* look for the xz magic header bytes */
if (is_format_xz(state) || is_format_lzma(state)) {
state->how = LZMA;
state->direct = 0;
return 0;
}
#ifdef HAVE_ZLIB_H
/* look for the gzip magic header bytes 31 and 139 */
if (strm->next_in[0] == 31) {
strm->avail_in--;
strm->next_in++;
if (strm->avail_in == 0 && xz_avail(state) == -1)
return -1;
if (strm->avail_in && strm->next_in[0] == 139) {
/* we have a gzip header, woo hoo! */
strm->avail_in--;
strm->next_in++;
/* skip rest of header */
if (NEXT() != 8) { /* compression method */
xz_error(state, LZMA_DATA_ERROR,
"unknown compression method");
return -1;
}
flags = NEXT();
if (flags & 0xe0) { /* reserved flag bits */
xz_error(state, LZMA_DATA_ERROR,
"unknown header flags set");
return -1;
}
NEXT(); /* modification time */
NEXT();
NEXT();
NEXT();
NEXT(); /* extra flags */
NEXT(); /* operating system */
if (flags & 4) { /* extra field */
len = (unsigned) NEXT();
len += (unsigned) NEXT() << 8;
while (len--)
if (NEXT() < 0)
break;
}
if (flags & 8) /* file name */
while (NEXT() > 0) ;
if (flags & 16) /* comment */
while (NEXT() > 0) ;
if (flags & 2) { /* header crc */
NEXT();
NEXT();
}
/* an unexpected end of file is not checked for here -- it will be
* noticed on the first request for uncompressed data */
/* set up for decompression */
inflateReset(&state->zstrm);
state->zstrm.adler = crc32(0L, Z_NULL, 0);
state->how = GZIP;
state->direct = 0;
return 0;
} else {
/* not a gzip file -- save first byte (31) and fall to raw i/o */
state->out[0] = 31;
state->have = 1;
}
}
#endif
/* doing raw i/o, save start of raw data for seeking, copy any leftover
* input to output -- this assumes that the output buffer is larger than
* the input buffer, which also assures space for gzungetc() */
state->raw = state->pos;
state->next = state->out;
if (strm->avail_in) {
memcpy(state->next + state->have, strm->next_in, strm->avail_in);
state->have += strm->avail_in;
strm->avail_in = 0;
}
state->how = COPY;
state->direct = 1;
return 0;
}
static int
xz_decomp(xz_statep state)
{
int ret;
unsigned had;
unsigned long crc, len;
lzma_stream *strm = &(state->strm);
lzma_action action = LZMA_RUN;
/* fill output buffer up to end of deflate stream */
had = strm->avail_out;
do {
/* get more input for inflate() */
if (strm->avail_in == 0 && xz_avail(state) == -1)
return -1;
if (strm->avail_in == 0) {
xz_error(state, LZMA_DATA_ERROR, "unexpected end of file");
return -1;
}
if (state->eof)
action = LZMA_FINISH;
/* decompress and handle errors */
#ifdef HAVE_ZLIB_H
if (state->how == GZIP) {
state->zstrm.avail_in = (uInt) state->strm.avail_in;
state->zstrm.next_in = (Bytef *) state->strm.next_in;
state->zstrm.avail_out = (uInt) state->strm.avail_out;
state->zstrm.next_out = (Bytef *) state->strm.next_out;
ret = inflate(&state->zstrm, Z_NO_FLUSH);
if (ret == Z_STREAM_ERROR || ret == Z_NEED_DICT) {
xz_error(state, Z_STREAM_ERROR,
"internal error: inflate stream corrupt");
return -1;
}
if (ret == Z_MEM_ERROR)
ret = LZMA_MEM_ERROR;
if (ret == Z_DATA_ERROR)
ret = LZMA_DATA_ERROR;
if (ret == Z_STREAM_END)
ret = LZMA_STREAM_END;
state->strm.avail_in = state->zstrm.avail_in;
state->strm.next_in = state->zstrm.next_in;
state->strm.avail_out = state->zstrm.avail_out;
state->strm.next_out = state->zstrm.next_out;
} else /* state->how == LZMA */
#endif
ret = lzma_code(strm, action);
if (ret == LZMA_MEM_ERROR) {
xz_error(state, LZMA_MEM_ERROR, "out of memory");
return -1;
}
if (ret == LZMA_DATA_ERROR) {
xz_error(state, LZMA_DATA_ERROR, "compressed data error");
return -1;
}
} while (strm->avail_out && ret != LZMA_STREAM_END);
/* update available output and crc check value */
state->have = had - strm->avail_out;
state->next = strm->next_out - state->have;
#ifdef HAVE_ZLIB_H
state->zstrm.adler =
crc32(state->zstrm.adler, state->next, state->have);
#endif
if (ret == LZMA_STREAM_END) {
#ifdef HAVE_ZLIB_H
if (state->how == GZIP) {
if (gz_next4(state, &crc) == -1 || gz_next4(state, &len) == -1) {
xz_error(state, LZMA_DATA_ERROR, "unexpected end of file");
return -1;
}
if (crc != state->zstrm.adler) {
xz_error(state, LZMA_DATA_ERROR, "incorrect data check");
return -1;
}
if (len != (state->zstrm.total_out & 0xffffffffL)) {
xz_error(state, LZMA_DATA_ERROR, "incorrect length check");
return -1;
}
state->strm.avail_in = 0;
state->strm.next_in = NULL;
state->strm.avail_out = 0;
state->strm.next_out = NULL;
} else
#endif
if (strm->avail_in != 0 || !state->eof) {
xz_error(state, LZMA_DATA_ERROR, "trailing garbage");
return -1;
}
state->how = LOOK; /* ready for next stream, once have is 0 (leave
* state->direct unchanged to remember how) */
}
/* good decompression */
return 0;
}
static int
xz_make(xz_statep state)
{
lzma_stream *strm = &(state->strm);
if (state->how == LOOK) { /* look for lzma / gzip header */
if (xz_head(state) == -1)
return -1;
if (state->have) /* got some data from xz_head() */
return 0;
}
if (state->how == COPY) { /* straight copy */
if (xz_load(state, state->out, state->size << 1, &(state->have)) ==
-1)
return -1;
state->next = state->out;
} else if (state->how == LZMA || state->how == GZIP) { /* decompress */
strm->avail_out = state->size << 1;
strm->next_out = state->out;
if (xz_decomp(state) == -1)
return -1;
}
return 0;
}
static int
xz_skip(xz_statep state, uint64_t len)
{
unsigned n;
/* skip over len bytes or reach end-of-file, whichever comes first */
while (len)
/* skip over whatever is in output buffer */
if (state->have) {
n = (uint64_t) state->have > len ?
(unsigned) len : state->have;
state->have -= n;
state->next += n;
state->pos += n;
len -= n;
}
/* output buffer empty -- return if we're at the end of the input */
else if (state->eof && state->strm.avail_in == 0)
break;
/* need more data to skip -- load up output buffer */
else {
/* get more output, looking for header if required */
if (xz_make(state) == -1)
return -1;
}
return 0;
}
int
__libxml2_xzread(xzFile file, void *buf, unsigned len)
{
unsigned got, n;
xz_statep state;
lzma_stream *strm;
/* get internal structure */
if (file == NULL)
return -1;
state = (xz_statep) file;
strm = &(state->strm);
/* check that we're reading and that there's no error */
if (state->err != LZMA_OK)
return -1;
/* since an int is returned, make sure len fits in one, otherwise return
* with an error (this avoids the flaw in the interface) */
if ((int) len < 0) {
xz_error(state, LZMA_BUF_ERROR,
"requested length does not fit in int");
return -1;
}
/* if len is zero, avoid unnecessary operations */
if (len == 0)
return 0;
/* process a skip request */
if (state->seek) {
state->seek = 0;
if (xz_skip(state, state->skip) == -1)
return -1;
}
/* get len bytes to buf, or less than len if at the end */
got = 0;
do {
/* first just try copying data from the output buffer */
if (state->have) {
n = state->have > len ? len : state->have;
memcpy(buf, state->next, n);
state->next += n;
state->have -= n;
}
/* output buffer empty -- return if we're at the end of the input */
else if (state->eof && strm->avail_in == 0)
break;
/* need output data -- for small len or new stream load up our output
* buffer */
else if (state->how == LOOK || len < (state->size << 1)) {
/* get more output, looking for header if required */
if (xz_make(state) == -1)
return -1;
continue; /* no progress yet -- go back to memcpy() above */
/* the copy above assures that we will leave with space in the
* output buffer, allowing at least one gzungetc() to succeed */
}
/* large len -- read directly into user buffer */
else if (state->how == COPY) { /* read directly */
if (xz_load(state, buf, len, &n) == -1)
return -1;
}
/* large len -- decompress directly into user buffer */
else { /* state->how == LZMA */
strm->avail_out = len;
strm->next_out = buf;
if (xz_decomp(state) == -1)
return -1;
n = state->have;
state->have = 0;
}
/* update progress */
len -= n;
buf = (char *) buf + n;
got += n;
state->pos += n;
} while (len);
/* return number of bytes read into user buffer (will fit in int) */
return (int) got;
}
int
__libxml2_xzclose(xzFile file)
{
int ret;
xz_statep state;
/* get internal structure */
if (file == NULL)
return LZMA_DATA_ERROR;
state = (xz_statep) file;
/* free memory and close file */
if (state->size) {
lzma_end(&(state->strm));
#ifdef HAVE_LIBZ_H
inflateEnd(&(state->zstrm));
#endif
free(state->out);
free(state->in);
}
free(state->path);
ret = close(state->fd);
free(state);
return ret ? ret : LZMA_OK;
}
#endif /* HAVE_LZMA_H */
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