/** * 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 */ #define IN_LIBXML #include "libxml.h" #ifdef HAVE_LZMA_H #include #ifdef HAVE_ERRNO_H #include #endif #ifdef HAVE_SYS_TYPES_H #include #endif #ifdef HAVE_SYS_STAT_H #include #endif #ifdef HAVE_FCNTL_H #include #endif #ifdef HAVE_UNISTD_H #include #endif #ifdef HAVE_STDLIB_H #include #endif #ifdef HAVE_ZLIB_H #include #endif #include #include "xzlib.h" #include /* 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 */ int init; /* is the iniflate stream initialized */ 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) xmlFree(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 = xmlMalloc(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 = xmlMalloc(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 */ state->init = 0; /* initialization of zlib data */ /* save the path name for error messages */ state->path = xmlMalloc(strlen(path) + 1); if (state->path == NULL) { xmlFree(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) { xmlFree(state->path); xmlFree(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 = xmlMalloc(7 + 3 * sizeof(int))) == NULL) return NULL; sprintf(path, "", fd); /* for debugging */ xz = xz_open(path, fd, mode); xmlFree(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); /* we can't use xmlFree on a string returned by zlib */ /* 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 = xmlMalloc(state->want); state->out = xmlMalloc(state->want << 1); if (state->in == NULL || state->out == NULL) { if (state->out != NULL) xmlFree(state->out); if (state->in != NULL) xmlFree(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) { xmlFree(state->out); xmlFree(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 (state->init == 0) { if (inflateInit2(&(state->zstrm), -15) != Z_OK) {/* raw inflate */ xmlFree(state->out); xmlFree(state->in); state->size = 0; xz_error(state, LZMA_MEM_ERROR, "out of memory"); return -1; } state->init = 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_ZLIB_H if (state->init == 1) inflateEnd(&(state->zstrm)); state->init = 0; #endif xmlFree(state->out); xmlFree(state->in); } xmlFree(state->path); ret = close(state->fd); xmlFree(state); return ret ? ret : LZMA_OK; } #endif /* HAVE_LZMA_H */