/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include <bio.h>#include <flate.h>#include "gzip.h" typedef struct	GZHead	GZHead; struct GZHead{	ulong	mtime;	char	*file;}; static	int	crcwrite(void *bout, void *buf, int n);static	int	get1(Biobuf *b);static	ulong	get4(Biobuf *b);static	int	gunzipf(char *file, int stdout);static	int	gunzip(int ofd, char *ofile, Biobuf *bin);static	void	header(Biobuf *bin, GZHead *h);static	void	trailer(Biobuf *bin, long wlen);static	void	error(char*, ...);#pragma	varargck	argpos	error	1 static	Biobuf	bin;static	ulong	crc;static	ulong	*crctab;static	int	debug;static	char	*delfile;static	vlong	gzok;static	char	*infile;static	int	settimes;static	int	table;static	int	verbose;static	int	wbad;static	ulong	wlen;static	jmp_buf	zjmp; voidusage(void){	fprint(2, "usage: gunzip [-ctvTD] [file ....]\n");	exits("usage");} voidmain(int argc, char *argv[]){	int i, ok, stdout; 	stdout = 0;	ARGBEGIN{	case 'D':		debug++;		break;	case 'c':		stdout++;		break;	case 't':		table++;		break;	case 'T':		settimes++;		break;	case 'v':		verbose++;		break;	default:		usage();		break;	}ARGEND 	crctab = mkcrctab(GZCRCPOLY);	ok = inflateinit();	if(ok != FlateOk)		sysfatal("inflateinit failed: %s", flateerr(ok)); 	if(argc == 0){		Binit(&bin, 0, OREAD);		settimes = 0;		infile = "<stdin>";		ok = gunzip(1, "<stdout>", &bin);	}else{		ok = 1;		if(stdout)			settimes = 0;		for(i = 0; i < argc; i++)			ok &= gunzipf(argv[i], stdout);	} 	exits(ok ? nil: "errors");} static intgunzipf(char *file, int stdout){	char ofile[256], *s;	int ofd, ifd, ok; 	infile = file;	ifd = open(file, OREAD);	if(ifd < 0){		fprint(2, "gunzip: can't open %s: %r\n", file);		return 0;	} 	Binit(&bin, ifd, OREAD);	if(Bgetc(&bin) != GZMAGIC1 || Bgetc(&bin) != GZMAGIC2 || Bgetc(&bin) != GZDEFLATE){		fprint(2, "gunzip: %s is not a gzip deflate file\n", file);		Bterm(&bin);		close(ifd);		return 0;	}	Bungetc(&bin);	Bungetc(&bin);	Bungetc(&bin); 	if(table)		ofd = -1;	else if(stdout){		ofd = 1;		strcpy(ofile, "<stdout>");	}else{		s = strrchr(file, '/');		if(s != nil)			s++;		else			s = file;		strecpy(ofile, ofile+sizeof ofile, s);		s = strrchr(ofile, '.');		if(s != nil && s != ofile && strcmp(s, ".gz") == 0)			*s = '\0';		else if(s != nil && strcmp(s, ".tgz") == 0)			strcpy(s, ".tar");		else if(strcmp(file, ofile) == 0){			fprint(2, "gunzip: can't overwrite %s\n", file);			Bterm(&bin);			close(ifd);			return 0;		} 		ofd = create(ofile, OWRITE, 0666);		if(ofd < 0){			fprint(2, "gunzip: can't create %s: %r\n", ofile);			Bterm(&bin);			close(ifd);			return 0;		}		delfile = ofile;	} 	wbad = 0;	ok = gunzip(ofd, ofile, &bin);	Bterm(&bin);	close(ifd);	if(wbad){		fprint(2, "gunzip: can't write %s: %r\n", ofile);		if(delfile)			remove(delfile);	}	delfile = nil;	if(!stdout && ofd >= 0)		close(ofd);	return ok;} static intgunzip(int ofd, char *ofile, Biobuf *bin){	Dir *d;	GZHead h;	int err; 	h.file = nil;	gzok = 0;	for(;;){		if(Bgetc(bin) < 0)			return 1;		Bungetc(bin); 		if(setjmp(zjmp))			return 0;		header(bin, &h);		gzok = 0; 		wlen = 0;		crc = 0; 		if(!table && verbose)			fprint(2, "extracting %s to %s\n", h.file, ofile); 		err = inflate((void*)ofd, crcwrite, bin, (int(*)(void*))Bgetc);		if(err != FlateOk)			error("inflate failed: %s", flateerr(err)); 		trailer(bin, wlen); 		if(table){			if(verbose)				print("%-32s %10ld %s", h.file, wlen, ctime(h.mtime));			else				print("%s\n", h.file);		}else if(settimes && h.mtime && (d=dirfstat(ofd)) != nil){			d->mtime = h.mtime;			dirfwstat(ofd, d);			free(d);		} 		free(h.file);		h.file = nil;		gzok = Boffset(bin);	}} static voidheader(Biobuf *bin, GZHead *h){	char *s;	int i, c, flag, ns, nsa; 	if(get1(bin) != GZMAGIC1 || get1(bin) != GZMAGIC2)		error("bad gzip file magic");	if(get1(bin) != GZDEFLATE)		error("unknown compression type"); 	flag = get1(bin);	if(flag & ~(GZFTEXT|GZFEXTRA|GZFNAME|GZFCOMMENT|GZFHCRC))		fprint(2, "gunzip: reserved flags set, data may not be decompressed correctly\n"); 	/* mod time */	h->mtime = get4(bin); 	/* extra flags */	get1(bin); 	/* OS type */	get1(bin); 	if(flag & GZFEXTRA)		for(i=get1(bin); i>0; i--)			get1(bin); 	/* name */	if(flag & GZFNAME){		nsa = 32;		ns = 0;		s = malloc(nsa);		if(s == nil)			error("out of memory");		while((c = get1(bin)) != 0){			s[ns++] = c;			if(ns >= nsa){				nsa += 32;				s = realloc(s, nsa);				if(s == nil)					error("out of memory");			}		}		s[ns] = '\0';		h->file = s;	}else		h->file = strdup("<unnamed file>"); 	/* comment */	if(flag & GZFCOMMENT)		while(get1(bin) != 0)			; 	/* crc16 */	if(flag & GZFHCRC){		get1(bin);		get1(bin);	}} static voidtrailer(Biobuf *bin, long wlen){	ulong tcrc;	long len; 	tcrc = get4(bin);	if(tcrc != crc)		error("crc mismatch"); 	len = get4(bin); 	if(len != wlen)		error("bad output length: expected %lud got %lud", wlen, len);} static ulongget4(Biobuf *b){	ulong v;	int i, c; 	v = 0;	for(i = 0; i < 4; i++){		c = Bgetc(b);		if(c < 0)			error("unexpected eof reading file information");		v |= c << (i * 8);	}	return v;} static intget1(Biobuf *b){	int c; 	c = Bgetc(b);	if(c < 0)		error("unexpected eof reading file information");	return c;} static intcrcwrite(void *out, void *buf, int n){	int fd, nw; 	wlen += n;	crc = blockcrc(crctab, crc, buf, n);	fd = (int)(uintptr)out;	if(fd < 0)		return n;	nw = write(fd, buf, n);	if(nw != n)		wbad = 1;	return nw;} static voiderror(char *fmt, ...){	va_list arg; 	if(gzok)		fprint(2, "gunzip: %s: corrupted data after byte %lld ignored\n", infile, gzok);	else{		fprint(2, "gunzip: ");		if(infile)			fprint(2, "%s: ", infile);		va_start(arg, fmt);		vfprint(2, fmt, arg);		va_end(arg);		fprint(2, "\n");			if(delfile != nil){			fprint(2, "gunzip: removing output file %s\n", delfile);			remove(delfile);			delfile = nil;		}	} 	longjmp(zjmp, 1);}