1 #include <u.h>
2 #include <libc.h>
3 #include <bio.h>
4 #include <flate.h>
5 #include "gzip.h"
6 
7 static	int	gzipf(char*, int);
8 static	int	gzip(char*, long, int, Biobuf*);
9 static	int	crcread(void *fd, void *buf, int n);
10 static	int	gzwrite(void *bout, void *buf, int n);
11 
12 static	Biobuf	bout;
13 static	u32int	crc;
14 static	u32int	*crctab;
15 static	int	debug;
16 static	int	eof;
17 static	int	level;
18 static	u32int	totr;
19 static	int	verbose;
20 
21 void
22 usage(void)
23 {
24 	fprint(2, "usage: gzip [-vcD] [-1-9] [file ...]\n");
25 	exits("usage");
26 }
27 
28 void
29 main(int argc, char *argv[])
30 {
31 	int i, ok, stdout;
32 	char **oargv;
33 
34 	oargv = argv;
35 	level = 6;
36 	stdout = 0;
37 	ARGBEGIN{
38 	case 'D':
39 		debug++;
40 		break;
41 	case 'd':
42 		/*
43 		 * gnu tar expects gzip -d to decompress
44 		 * humor it.  ugh.
45 		 */
46 		/* remove -d from command line - magic! */
47 		if(strcmp(argv[0], "-d") == 0){
48 			while(*argv++)
49 				*(argv-1) = *argv;
50 		}else
51 			memmove(_args-1, _args, strlen(_args)+1);
52 		exec("gunzip", oargv);
53 		sysfatal("exec gunzip failed");
54 		break;
55 	case 'f':
56 		/* force */
57 		break;
58 	case 'v':
59 		verbose++;
60 		break;
61 	case 'c':
62 		stdout = 1;
63 		break;
64 	case '1': case '2': case '3': case '4':
65 	case '5': case '6': case '7': case '8': case '9':
66 		level = ARGC() - '0';
67 		break;
68 	default:
69 		usage();
70 		break;
71 	}ARGEND
72 
73 	crctab = mkcrctab(GZCRCPOLY);
74 	ok = deflateinit();
75 	if(ok != FlateOk)
76 		sysfatal("deflateinit failed: %s\n", flateerr(ok));
77 
78 	if(argc == 0){
79 		Binit(&bout, 1, OWRITE);
80 		ok = gzip(nil, time(0), 0, &bout);
81 		Bterm(&bout);
82 	}else{
83 		ok = 1;
84 		for(i = 0; i < argc; i++)
85 			ok &= gzipf(argv[i], stdout);
86 	}
87 	exits(ok ? nil: "errors");
88 }
89 
90 static int
91 gzipf(char *file, int stdout)
92 {
93 	Dir *dir;
94 	char ofile[256], *f, *s;
95 	int ifd, ofd, ok;
96 
97 	ifd = open(file, OREAD);
98 	if(ifd < 0){
99 		fprint(2, "gzip: can't open %s: %r\n", file);
100 		return 0;
101 	}
102 	dir = dirfstat(ifd);
103 	if(dir == nil){
104 		fprint(2, "gzip: can't stat %s: %r\n", file);
105 		close(ifd);
106 		return 0;
107 	}
108 	if(dir->mode & DMDIR){
109 		fprint(2, "gzip: can't compress a directory\n");
110 		close(ifd);
111 		free(dir);
112 		return 0;
113 	}
114 
115 	if(stdout){
116 		ofd = 1;
117 		strcpy(ofile, "<stdout>");
118 	}else{
119 		f = strrchr(file, '/');
120 		if(f != nil)
121 			f++;
122 		else
123 			f = file;
124 		s = strrchr(f, '.');
125 		if(s != nil && s != ofile && strcmp(s, ".tar") == 0){
126 			*s = '\0';
127 			snprint(ofile, sizeof(ofile), "%s.tgz", f);
128 		}else
129 			snprint(ofile, sizeof(ofile), "%s.gz", f);
130 		ofd = create(ofile, OWRITE, 0666);
131 		if(ofd < 0){
132 			fprint(2, "gzip: can't open %s: %r\n", ofile);
133 			close(ifd);
134 			return 0;
135 		}
136 	}
137 
138 	if(verbose)
139 		fprint(2, "compressing %s to %s\n", file, ofile);
140 
141 	Binit(&bout, ofd, OWRITE);
142 	ok = gzip(file, dir->mtime, ifd, &bout);
143 	if(!ok || Bflush(&bout) < 0){
144 		fprint(2, "gzip: error writing %s: %r\n", ofile);
145 		if(!stdout)
146 			remove(ofile);
147 	}
148 	Bterm(&bout);
149 	free(dir);
150 	close(ifd);
151 	close(ofd);
152 	return ok;
153 }
154 
155 static int
156 gzip(char *file, long mtime, int ifd, Biobuf *bout)
157 {
158 	int flags, err;
159 
160 	flags = 0;
161 	Bputc(bout, GZMAGIC1);
162 	Bputc(bout, GZMAGIC2);
163 	Bputc(bout, GZDEFLATE);
164 
165 	if(file != nil)
166 		flags |= GZFNAME;
167 	Bputc(bout, flags);
168 
169 	Bputc(bout, mtime);
170 	Bputc(bout, mtime>>8);
171 	Bputc(bout, mtime>>16);
172 	Bputc(bout, mtime>>24);
173 
174 	Bputc(bout, 0);
175 	Bputc(bout, GZOSINFERNO);
176 
177 	if(flags & GZFNAME)
178 		Bwrite(bout, file, strlen(file)+1);
179 
180 	crc = 0;
181 	eof = 0;
182 	totr = 0;
183 	err = deflate(bout, gzwrite, (void*)(uintptr)ifd, crcread, level, debug);
184 	if(err != FlateOk){
185 		fprint(2, "gzip: deflate failed: %s\n", flateerr(err));
186 		return 0;
187 	}
188 
189 	Bputc(bout, crc);
190 	Bputc(bout, crc>>8);
191 	Bputc(bout, crc>>16);
192 	Bputc(bout, crc>>24);
193 
194 	Bputc(bout, totr);
195 	Bputc(bout, totr>>8);
196 	Bputc(bout, totr>>16);
197 	Bputc(bout, totr>>24);
198 
199 	return 1;
200 }
201 
202 static int
203 crcread(void *fd, void *buf, int n)
204 {
205 	int nr, m;
206 
207 	nr = 0;
208 	for(; !eof && n > 0; n -= m){
209 		m = read((int)(uintptr)fd, (char*)buf+nr, n);
210 		if(m <= 0){
211 			eof = 1;
212 			if(m < 0)
213 				return -1;
214 			break;
215 		}
216 		nr += m;
217 	}
218 	crc = blockcrc(crctab, crc, buf, nr);
219 	totr += nr;
220 	return nr;
221 }
222 
223 static int
224 gzwrite(void *bout, void *buf, int n)
225 {
226 	if(n != Bwrite(bout, buf, n)){
227 		eof = 1;
228 		return -1;
229 	}
230 	return n;
231 }