/* * $Id: kern_gzio.c,v 1.6 2008-10-18 22:54:45 lbazinet Exp $ * * core_gzip.c -- gzip routines used in compressing user process cores * * This file is derived from src/lib/libz/gzio.c in FreeBSD. */ /* gzio.c -- IO on .gz files * Copyright (C) 1995-1998 Jean-loup Gailly. * For conditions of distribution and use, see copyright notice in zlib.h * */ /* @(#) $FreeBSD$ */ #include #include #include #include #include #include #include #include #include #include #define GZ_HEADER_LEN 10 #ifndef Z_BUFSIZE # ifdef MAXSEG_64K # define Z_BUFSIZE 4096 /* minimize memory usage for 16-bit DOS */ # else # define Z_BUFSIZE 16384 # endif #endif #ifndef Z_PRINTF_BUFSIZE # define Z_PRINTF_BUFSIZE 4096 #endif #define ALLOC(size) malloc(size, M_TEMP, M_WAITOK | M_ZERO) #define TRYFREE(p) {if (p) free(p, M_TEMP);} static 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 */ typedef struct gz_stream { z_stream stream; int z_err; /* error code for last stream operation */ int z_eof; /* set if end of input file */ struct vnode *file; /* vnode pointer of .gz file */ Byte *inbuf; /* input buffer */ Byte *outbuf; /* output buffer */ uLong crc; /* crc32 of uncompressed data */ char *msg; /* error message */ char *path; /* path name for debugging only */ int transparent; /* 1 if input file is not a .gz file */ char mode; /* 'w' or 'r' */ long startpos; /* start of compressed data in file (header skipped) */ off_t outoff; /* current offset in output file */ int flags; } gz_stream; local int do_flush OF((gzFile file, int flush)); local int destroy OF((gz_stream *s)); local void putU32 OF((gz_stream *file, uint32_t x)); local void *gz_alloc OF((void *notused, u_int items, u_int size)); local void gz_free OF((void *notused, void *ptr)); /* =========================================================================== Opens a gzip (.gz) file for reading or writing. The mode parameter is as in fopen ("rb" or "wb"). The file is given either by file descriptor or path name (if fd == -1). gz_open return NULL if the file could not be opened or if there was insufficient memory to allocate the (de)compression state; errno can be checked to distinguish the two cases (if errno is zero, the zlib error is Z_MEM_ERROR). */ gzFile gz_open (path, mode, vp) const char *path; const char *mode; struct vnode *vp; { int err; int level = Z_DEFAULT_COMPRESSION; /* compression level */ int strategy = Z_DEFAULT_STRATEGY; /* compression strategy */ const char *p = mode; gz_stream *s; char fmode[80]; /* copy of mode, without the compression level */ char *m = fmode; ssize_t resid; int error; char buf[GZ_HEADER_LEN + 1]; if (!path || !mode) return Z_NULL; s = (gz_stream *)ALLOC(sizeof(gz_stream)); if (!s) return Z_NULL; s->stream.zalloc = (alloc_func)gz_alloc; s->stream.zfree = (free_func)gz_free; s->stream.opaque = (voidpf)0; s->stream.next_in = s->inbuf = Z_NULL; s->stream.next_out = s->outbuf = Z_NULL; s->stream.avail_in = s->stream.avail_out = 0; s->file = NULL; s->z_err = Z_OK; s->z_eof = 0; s->crc = 0; s->msg = NULL; s->transparent = 0; s->outoff = 0; s->flags = 0; s->path = (char*)ALLOC(strlen(path)+1); if (s->path == NULL) { return destroy(s), (gzFile)Z_NULL; } strcpy(s->path, path); /* do this early for debugging */ s->mode = '\0'; do { if (*p == 'r') s->mode = 'r'; if (*p == 'w' || *p == 'a') s->mode = 'w'; if (*p >= '0' && *p <= '9') { level = *p - '0'; } else if (*p == 'f') { strategy = Z_FILTERED; } else if (*p == 'h') { strategy = Z_HUFFMAN_ONLY; } else { *m++ = *p; /* copy the mode */ } } while (*p++ && m != fmode + sizeof(fmode)); if (s->mode != 'w') { log(LOG_ERR, "gz_open: mode is not w (%c)\n", s->mode); return destroy(s), (gzFile)Z_NULL; } err = deflateInit2(&(s->stream), level, Z_DEFLATED, -MAX_WBITS, DEF_MEM_LEVEL, strategy); /* windowBits is passed < 0 to suppress zlib header */ s->stream.next_out = s->outbuf = (Byte*)ALLOC(Z_BUFSIZE); if (err != Z_OK || s->outbuf == Z_NULL) { return destroy(s), (gzFile)Z_NULL; } s->stream.avail_out = Z_BUFSIZE; s->file = vp; /* Write a very simple .gz header: */ snprintf(buf, sizeof(buf), "%c%c%c%c%c%c%c%c%c%c", gz_magic[0], gz_magic[1], Z_DEFLATED, 0 /*flags*/, 0,0,0,0 /*time*/, 0 /*xflags*/, OS_CODE); if ((error = vn_rdwr(UIO_WRITE, s->file, buf, GZ_HEADER_LEN, s->outoff, UIO_SYSSPACE, IO_UNIT, curproc->p_ucred, NOCRED, &resid, curthread))) { s->outoff += GZ_HEADER_LEN - resid; return destroy(s), (gzFile)Z_NULL; } s->outoff += GZ_HEADER_LEN; s->startpos = 10L; return (gzFile)s; } /* =========================================================================== * Cleanup then free the given gz_stream. Return a zlib error code. Try freeing in the reverse order of allocations. */ local int destroy (s) gz_stream *s; { int err = Z_OK; if (!s) return Z_STREAM_ERROR; TRYFREE(s->msg); if (s->stream.state != NULL) { if (s->mode == 'w') { err = deflateEnd(&(s->stream)); } } if (s->z_err < 0) err = s->z_err; TRYFREE(s->inbuf); TRYFREE(s->outbuf); TRYFREE(s->path); TRYFREE(s); return err; } /* =========================================================================== Writes the given number of uncompressed bytes into the compressed file. gzwrite returns the number of bytes actually written (0 in case of error). */ int ZEXPORT gzwrite (file, buf, len) gzFile file; const voidp buf; unsigned len; { gz_stream *s = (gz_stream*)file; off_t curoff; size_t resid; int error; if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR; s->stream.next_in = (Bytef*)buf; s->stream.avail_in = len; curoff = s->outoff; while (s->stream.avail_in != 0) { if (s->stream.avail_out == 0) { s->stream.next_out = s->outbuf; error = vn_rdwr_inchunks(UIO_WRITE, s->file, s->outbuf, Z_BUFSIZE, curoff, UIO_SYSSPACE, IO_UNIT, curproc->p_ucred, NOCRED, &resid, curthread); if (error) { log(LOG_ERR, "gzwrite: vn_rdwr return %d\n", error); curoff += Z_BUFSIZE - resid; s->z_err = Z_ERRNO; break; } curoff += Z_BUFSIZE; s->stream.avail_out = Z_BUFSIZE; } s->z_err = deflate(&(s->stream), Z_NO_FLUSH); if (s->z_err != Z_OK) { log(LOG_ERR, "gzwrite: deflate returned error %d\n", s->z_err); break; } } s->crc = ~crc32_raw(buf, len, ~s->crc); s->outoff = curoff; return (int)(len - s->stream.avail_in); } /* =========================================================================== Flushes all pending output into the compressed file. The parameter flush is as in the deflate() function. */ local int do_flush (file, flush) gzFile file; int flush; { uInt len; int done = 0; gz_stream *s = (gz_stream*)file; off_t curoff = s->outoff; size_t resid; int error; if (s == NULL || s->mode != 'w') return Z_STREAM_ERROR; if (s->stream.avail_in) { log(LOG_WARNING, "do_flush: avail_in non-zero on entry\n"); } s->stream.avail_in = 0; /* should be zero already anyway */ for (;;) { len = Z_BUFSIZE - s->stream.avail_out; if (len != 0) { error = vn_rdwr_inchunks(UIO_WRITE, s->file, s->outbuf, len, curoff, UIO_SYSSPACE, IO_UNIT, curproc->p_ucred, NOCRED, &resid, curthread); if (error) { s->z_err = Z_ERRNO; s->outoff = curoff + len - resid; return Z_ERRNO; } s->stream.next_out = s->outbuf; s->stream.avail_out = Z_BUFSIZE; curoff += len; } if (done) break; s->z_err = deflate(&(s->stream), flush); /* Ignore the second of two consecutive flushes: */ if (len == 0 && s->z_err == Z_BUF_ERROR) s->z_err = Z_OK; /* deflate has finished flushing only when it hasn't used up * all the available space in the output buffer: */ done = (s->stream.avail_out != 0 || s->z_err == Z_STREAM_END); if (s->z_err != Z_OK && s->z_err != Z_STREAM_END) break; } s->outoff = curoff; return s->z_err == Z_STREAM_END ? Z_OK : s->z_err; } int ZEXPORT gzflush (file, flush) gzFile file; int flush; { gz_stream *s = (gz_stream*)file; int err = do_flush (file, flush); if (err) return err; return s->z_err == Z_STREAM_END ? Z_OK : s->z_err; } /* =========================================================================== Outputs a long in LSB order to the given file */ local void putU32 (s, x) gz_stream *s; uint32_t x; { uint32_t xx; off_t curoff = s->outoff; ssize_t resid; #if BYTE_ORDER == BIG_ENDIAN xx = bswap32(x); #else xx = x; #endif vn_rdwr(UIO_WRITE, s->file, (caddr_t)&xx, sizeof(xx), curoff, UIO_SYSSPACE, IO_UNIT, curproc->p_ucred, NOCRED, &resid, curthread); s->outoff += sizeof(xx) - resid; } /* =========================================================================== Flushes all pending output if necessary, closes the compressed file and deallocates all the (de)compression state. */ int ZEXPORT gzclose (file) gzFile file; { int err; gz_stream *s = (gz_stream*)file; if (s == NULL) return Z_STREAM_ERROR; if (s->mode == 'w') { err = do_flush (file, Z_FINISH); if (err != Z_OK) { log(LOG_ERR, "gzclose: do_flush failed (err %d)\n", err); return destroy((gz_stream*)file); } #if 0 printf("gzclose: putting crc: %lld total: %lld\n", (long long)s->crc, (long long)s->stream.total_in); printf("sizeof uLong = %d\n", (int)sizeof(uLong)); #endif putU32 (s, s->crc); putU32 (s, (uint32_t) s->stream.total_in); } return destroy((gz_stream*)file); } /* * Space allocation and freeing routines for use by zlib routines when called * from gzip modules. */ static void * gz_alloc(void *notused __unused, u_int items, u_int size) { void *ptr; MALLOC(ptr, void *, items * size, M_TEMP, M_NOWAIT | M_ZERO); return ptr; } static void gz_free(void *opaque __unused, void *ptr) { FREE(ptr, M_TEMP); }