uudecode.c revision 111586 
1/*-
2 * Copyright (c) 1983, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35static const char copyright[] =
36"@(#) Copyright (c) 1983, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n";
38#endif /* not lint */
39
40#if 0
41#ifndef lint
42static char sccsid[] = "@(#)uudecode.c	8.2 (Berkeley) 4/2/94";
43#endif /* not lint */
44#endif
45
46#include <sys/cdefs.h>
47__FBSDID("$FreeBSD: head/usr.bin/uudecode/uudecode.c 111586 2003-02-27 02:24:01Z fanf $");
48
49/*
50 * uudecode [file ...]
51 *
52 * create the specified file, decoding as you go.
53 * used with uuencode.
54 */
55#include <sys/param.h>
56#include <sys/socket.h>
57#include <sys/stat.h>
58
59#include <netinet/in.h>
60
61#include <err.h>
62#include <errno.h>
63#include <fcntl.h>
64#include <pwd.h>
65#include <resolv.h>
66#include <stdio.h>
67#include <stdlib.h>
68#include <string.h>
69#include <unistd.h>
70
71static const char *infile, *outfile;
72static FILE *infp, *outfp;
73static int cflag, iflag, oflag, pflag, sflag;
74
75static void	usage(void);
76static int	decode(void);
77static int	decode2(void);
78static int	uu_decode(void);
79static int	base64_decode(void);
80
81int
82main(int argc, char *argv[])
83{
84	int rval, ch;
85
86	while ((ch = getopt(argc, argv, "cio:ps")) != -1) {
87		switch(ch) {
88		case 'c':
89			if (oflag)
90				usage();
91			cflag = 1; /* multiple uudecode'd files */
92			break;
93		case 'i':
94			iflag = 1; /* ask before override files */
95			break;
96		case 'o':
97			if (cflag || pflag || sflag)
98				usage();
99			oflag = 1; /* output to the specified file */
100			sflag = 1; /* do not strip pathnames for output */
101			outfile = optarg; /* set the output filename */
102			break;
103		case 'p':
104			if (oflag)
105				usage();
106			pflag = 1; /* print output to stdout */
107			break;
108		case 's':
109			if (oflag)
110				usage();
111			sflag = 1; /* do not strip pathnames for output */
112			break;
113		default:
114			usage();
115		}
116	}
117        argc -= optind;
118        argv += optind;
119
120	if (*argv) {
121		rval = 0;
122		do {
123			infp = fopen(infile = *argv, "r");
124			if (infp == NULL) {
125				warn("%s", *argv);
126				rval = 1;
127				continue;
128			}
129			rval |= decode();
130			fclose(infp);
131		} while (*++argv);
132	} else {
133		infile = "stdin";
134		infp = stdin;
135		rval = decode();
136	}
137	exit(rval);
138}
139
140static int
141decode(void)
142{
143	int r, v;
144
145	v = decode2();
146	if (v == EOF) {
147		warnx("%s: missing or bad \"begin\" line", infile);
148		return (1);
149	}
150	for (r = v; cflag; r |= v) {
151		v = decode2();
152		if (v == EOF)
153			break;
154	}
155	return (r);
156}
157
158static int
159decode2(void)
160{
161	int base64, flags, fd, mode;
162	size_t n, m;
163	char *p, *q;
164	void *handle;
165	struct passwd *pw;
166	struct stat st;
167	char buf[MAXPATHLEN+1];
168
169	base64 = 0;
170	/* search for header line */
171	for (;;) {
172		if (fgets(buf, sizeof(buf), infp) == NULL)
173			return (EOF);
174		p = buf;
175		if (strncmp(p, "begin-base64 ", 13) == 0) {
176			base64 = 1;
177			p += 13;
178		} else if (strncmp(p, "begin ", 6) == 0)
179			p += 6;
180		else
181			continue;
182		/* p points to mode */
183		q = strchr(p, ' ');
184		if (q == NULL)
185			continue;
186		*q++ = '\0';
187		/* q points to filename */
188		n = strlen(q);
189		while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
190			q[--n] = '\0';
191		/* found valid header? */
192		if (n > 0)
193			break;
194	}
195
196	handle = setmode(p);
197	if (handle == NULL) {
198		warnx("%s: unable to parse file mode", infile);
199		return (1);
200	}
201	mode = getmode(handle, 0) & 0666;
202	free(handle);
203
204	if (sflag) {
205		/* don't strip, so try ~user/file expansion */
206		p = NULL;
207		pw = NULL;
208		if (*q == '~')
209			p = strchr(q, '/');
210		if (p != NULL) {
211			*p = '\0';
212			pw = getpwnam(q + 1);
213			*p = '/';
214		}
215		if (pw != NULL) {
216			n = strlen(pw->pw_dir);
217			if (buf + n > p) {
218				/* make room */
219				m = strlen(p);
220				if (sizeof(buf) < n + m) {
221					warnx("%s: bad output filename",
222					    infile);
223					return (1);
224				}
225				p = memmove(buf + n, p, m);
226			}
227			q = memcpy(p - n, pw->pw_dir, n);
228		}
229	} else if (strcmp(q, "/dev/stdout") != 0) {
230		/* strip down to leaf name */
231		p = strrchr(q, '/');
232		if (p != NULL)
233			q = p + 1;
234	}
235	if (!oflag)
236		outfile = q;
237
238	/* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
239	if (pflag || strcmp(outfile, "/dev/stdout") == 0)
240		outfp = stdout;
241	else {
242		flags = O_WRONLY|O_CREAT|O_EXCL;
243		if (lstat(outfile, &st) == 0) {
244			if (iflag) {
245				warnc(EEXIST, "%s: %s", infile, outfile);
246				return (0);
247			}
248			switch (st.st_mode & S_IFMT) {
249			case S_IFREG:
250			case S_IFLNK:
251				/* avoid symlink attacks */
252				if (unlink(outfile) == 0 || errno == ENOENT)
253					break;
254				warn("%s: unlink %s", infile, outfile);
255				return (1);
256			case S_IFDIR:
257				warnc(EISDIR, "%s: %s", infile, outfile);
258				return (1);
259			default:
260				if (oflag) {
261					/* trust command-line names */
262					flags &= ~O_EXCL;
263					break;
264				}
265				warnc(EEXIST, "%s: %s", infile, outfile);
266				return (1);
267			}
268		} else if (errno != ENOENT) {
269			warn("%s: %s", infile, outfile);
270			return (1);
271		}
272		if ((fd = open(outfile, flags, mode)) < 0 ||
273		    (outfp = fdopen(fd, "w")) == NULL) {
274			warn("%s: %s", infile, outfile);
275			return (1);
276		}
277	}
278
279	if (base64)
280		return (base64_decode());
281	else
282		return (uu_decode());
283}
284
285static int
286uu_decode(void)
287{
288	int i, ch;
289	char *p;
290	char buf[MAXPATHLEN+1];
291
292	/* for each input line */
293	for (;;) {
294		if (fgets(p = buf, sizeof(buf), infp) == NULL) {
295			warnx("%s: short file", infile);
296			return (1);
297		}
298
299#define	DEC(c)	(((c) - ' ') & 077)		/* single character decode */
300#define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
301
302#define OUT_OF_RANGE do {						\
303	warnx("%s: %s: character out of range: [%d-%d]",		\
304	    infile, outfile, 1 + ' ', 077 + ' ' + 1);			\
305        return (1);							\
306} while (0)
307
308		/*
309		 * `i' is used to avoid writing out all the characters
310		 * at the end of the file.
311		 */
312		if ((i = DEC(*p)) <= 0)
313			break;
314		for (++p; i > 0; p += 4, i -= 3)
315			if (i >= 3) {
316				if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
317				     IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
318                                	OUT_OF_RANGE;
319
320				ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
321				putc(ch, outfp);
322				ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
323				putc(ch, outfp);
324				ch = DEC(p[2]) << 6 | DEC(p[3]);
325				putc(ch, outfp);
326			}
327			else {
328				if (i >= 1) {
329					if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
330	                                	OUT_OF_RANGE;
331					ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
332					putc(ch, outfp);
333				}
334				if (i >= 2) {
335					if (!(IS_DEC(*(p + 1)) &&
336						IS_DEC(*(p + 2))))
337		                                OUT_OF_RANGE;
338
339					ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
340					putc(ch, outfp);
341				}
342				if (i >= 3) {
343					if (!(IS_DEC(*(p + 2)) &&
344						IS_DEC(*(p + 3))))
345		                                OUT_OF_RANGE;
346					ch = DEC(p[2]) << 6 | DEC(p[3]);
347					putc(ch, outfp);
348				}
349			}
350	}
351	if (fgets(buf, sizeof(buf), infp) == NULL ||
352	    (strcmp(buf, "end") && strcmp(buf, "end\n") &&
353	     strcmp(buf, "end\r\n"))) {
354		warnx("%s: no \"end\" line", infile);
355		return (1);
356	}
357	if (fclose(outfp) != 0) {
358		warnx("%s: %s", infile, outfile);
359		return (1);
360	}
361	return (0);
362}
363
364static int
365base64_decode(void)
366{
367	int n;
368	char inbuf[MAXPATHLEN+1];
369	unsigned char outbuf[MAXPATHLEN * 4];
370
371	for (;;) {
372		if (fgets(inbuf, sizeof(inbuf), infp) == NULL) {
373			warnx("%s: short file", infile);
374			return (1);
375		}
376		if (strcmp(inbuf, "====") == 0 ||
377		    strcmp(inbuf, "====\n") == 0 ||
378		    strcmp(inbuf, "====\r\n") == 0) {
379			if (fclose(outfp) != 0) {
380				warnx("%s: %s", infile, outfile);
381				return (1);
382			}
383			return (0);
384		}
385		n = strlen(inbuf);
386		while (n > 0 && (inbuf[n-1] == '\n' || inbuf[n-1] == '\r'))
387			inbuf[--n] = '\0';
388		n = b64_pton(inbuf, outbuf, sizeof(outbuf));
389		if (n < 0) {
390			warnx("%s: %s: error decoding base64 input stream", infile, outfile);
391			return (1);
392		}
393		fwrite(outbuf, 1, n, outfp);
394	}
395}
396
397static void
398usage(void)
399{
400	(void)fprintf(stderr,
401"usage: uudecode [-cips] [file ...]\n"
402"       uudecode [-i] -o output_file [file]\n"
403"       b64decode [-cips] [file ...]\n"
404"       b64decode [-i] -o output_file [file]\n");
405	exit(1);
406}
407