4bb74a4762
careless users vulnerable to terminal control sequence attacks, since they expect uudecode to just drop (or overwrite) a file in the current directory. POSIX also says that the full pathname from the input should be used when writing a file, which we only do if the -s (shoot me in the foot) option is specified; therefore this revision means that you now need to use -s for standard /dev/stdout handling.
440 lines
9.8 KiB
C
440 lines
9.8 KiB
C
/*-
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static const char copyright[] =
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"@(#) Copyright (c) 1983, 1993\n\
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The Regents of the University of California. All rights reserved.\n";
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#endif /* not lint */
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#if 0
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#ifndef lint
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static char sccsid[] = "@(#)uudecode.c 8.2 (Berkeley) 4/2/94";
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#endif /* not lint */
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#endif
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* uudecode [file ...]
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*
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* create the specified file, decoding as you go.
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* used with uuencode.
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*/
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <netinet/in.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <libgen.h>
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#include <pwd.h>
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#include <resolv.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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static const char *infile, *outfile;
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static FILE *infp, *outfp;
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static int base64, cflag, iflag, oflag, pflag, rflag, sflag;
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static void usage(void);
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static int decode(void);
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static int decode2(void);
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static int uu_decode(void);
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static int base64_decode(void);
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int
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main(int argc, char *argv[])
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{
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int rval, ch;
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if (strcmp(basename(argv[0]), "b64decode") == 0)
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base64 = 1;
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while ((ch = getopt(argc, argv, "cimo:prs")) != -1) {
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switch(ch) {
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case 'c':
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if (oflag || rflag)
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usage();
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cflag = 1; /* multiple uudecode'd files */
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break;
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case 'i':
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iflag = 1; /* ask before override files */
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break;
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case 'm':
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base64 = 1;
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break;
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case 'o':
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if (cflag || pflag || rflag || sflag)
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usage();
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oflag = 1; /* output to the specified file */
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sflag = 1; /* do not strip pathnames for output */
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outfile = optarg; /* set the output filename */
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break;
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case 'p':
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if (oflag)
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usage();
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pflag = 1; /* print output to stdout */
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break;
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case 'r':
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if (cflag || oflag)
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usage();
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rflag = 1; /* decode raw data */
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break;
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case 's':
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if (oflag)
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usage();
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sflag = 1; /* do not strip pathnames for output */
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break;
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default:
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usage();
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}
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}
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argc -= optind;
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argv += optind;
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if (*argv) {
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rval = 0;
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do {
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infp = fopen(infile = *argv, "r");
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if (infp == NULL) {
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warn("%s", *argv);
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rval = 1;
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continue;
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}
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rval |= decode();
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fclose(infp);
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} while (*++argv);
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} else {
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infile = "stdin";
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infp = stdin;
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rval = decode();
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}
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exit(rval);
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}
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static int
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decode(void)
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{
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int r, v;
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if (rflag) {
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/* relaxed alternative to decode2() */
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outfile = "/dev/stdout";
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outfp = stdout;
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if (base64)
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return (base64_decode());
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else
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return (uu_decode());
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}
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v = decode2();
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if (v == EOF) {
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warnx("%s: missing or bad \"begin\" line", infile);
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return (1);
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}
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for (r = v; cflag; r |= v) {
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v = decode2();
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if (v == EOF)
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break;
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}
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return (r);
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}
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static int
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decode2(void)
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{
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int flags, fd, mode;
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size_t n, m;
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char *p, *q;
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void *handle;
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struct passwd *pw;
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struct stat st;
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char buf[MAXPATHLEN+1];
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base64 = 0;
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/* search for header line */
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for (;;) {
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if (fgets(buf, sizeof(buf), infp) == NULL)
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return (EOF);
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p = buf;
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if (strncmp(p, "begin-base64 ", 13) == 0) {
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base64 = 1;
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p += 13;
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} else if (strncmp(p, "begin ", 6) == 0)
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p += 6;
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else
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continue;
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/* p points to mode */
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q = strchr(p, ' ');
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if (q == NULL)
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continue;
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*q++ = '\0';
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/* q points to filename */
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n = strlen(q);
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while (n > 0 && (q[n-1] == '\n' || q[n-1] == '\r'))
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q[--n] = '\0';
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/* found valid header? */
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if (n > 0)
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break;
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}
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handle = setmode(p);
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if (handle == NULL) {
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warnx("%s: unable to parse file mode", infile);
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return (1);
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}
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mode = getmode(handle, 0) & 0666;
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free(handle);
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if (sflag) {
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/* don't strip, so try ~user/file expansion */
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p = NULL;
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pw = NULL;
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if (*q == '~')
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p = strchr(q, '/');
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if (p != NULL) {
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*p = '\0';
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pw = getpwnam(q + 1);
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*p = '/';
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}
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if (pw != NULL) {
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n = strlen(pw->pw_dir);
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if (buf + n > p) {
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/* make room */
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m = strlen(p);
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if (sizeof(buf) < n + m) {
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warnx("%s: bad output filename",
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infile);
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return (1);
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}
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p = memmove(buf + n, p, m);
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}
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q = memcpy(p - n, pw->pw_dir, n);
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}
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} else {
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/* strip down to leaf name */
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p = strrchr(q, '/');
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if (p != NULL)
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q = p + 1;
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}
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if (!oflag)
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outfile = q;
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/* POSIX says "/dev/stdout" is a 'magic cookie' not a special file. */
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if (pflag || strcmp(outfile, "/dev/stdout") == 0)
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outfp = stdout;
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else {
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flags = O_WRONLY|O_CREAT|O_EXCL;
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if (lstat(outfile, &st) == 0) {
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if (iflag) {
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warnc(EEXIST, "%s: %s", infile, outfile);
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return (0);
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}
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switch (st.st_mode & S_IFMT) {
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case S_IFREG:
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case S_IFLNK:
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/* avoid symlink attacks */
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if (unlink(outfile) == 0 || errno == ENOENT)
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break;
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warn("%s: unlink %s", infile, outfile);
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return (1);
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case S_IFDIR:
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warnc(EISDIR, "%s: %s", infile, outfile);
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return (1);
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default:
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if (oflag) {
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/* trust command-line names */
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flags &= ~O_EXCL;
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break;
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}
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warnc(EEXIST, "%s: %s", infile, outfile);
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return (1);
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}
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} else if (errno != ENOENT) {
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warn("%s: %s", infile, outfile);
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return (1);
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}
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if ((fd = open(outfile, flags, mode)) < 0 ||
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(outfp = fdopen(fd, "w")) == NULL) {
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warn("%s: %s", infile, outfile);
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return (1);
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}
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}
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if (base64)
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return (base64_decode());
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else
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return (uu_decode());
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}
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static int
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getline(char *buf, size_t size)
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{
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if (fgets(buf, size, infp) != NULL)
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return (2);
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if (rflag)
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return (0);
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warnx("%s: %s: short file", infile, outfile);
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return (1);
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}
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static int
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checkend(const char *ptr, const char *end, const char *msg)
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{
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size_t n;
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n = strlen(end);
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if (strncmp(ptr, end, n) != 0 ||
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strspn(ptr + n, " \t\r\n") != strlen(ptr + n)) {
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warnx("%s: %s: %s", infile, outfile, msg);
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return (1);
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}
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if (fclose(outfp) != 0) {
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warn("%s: %s", infile, outfile);
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return (1);
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}
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return (0);
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}
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static int
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uu_decode(void)
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{
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int i, ch;
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char *p;
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char buf[MAXPATHLEN+1];
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/* for each input line */
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for (;;) {
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switch (getline(buf, sizeof(buf))) {
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case 0: return (0);
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case 1: return (1);
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}
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#define DEC(c) (((c) - ' ') & 077) /* single character decode */
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#define IS_DEC(c) ( (((c) - ' ') >= 0) && (((c) - ' ') <= 077 + 1) )
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#define OUT_OF_RANGE do { \
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warnx("%s: %s: character out of range: [%d-%d]", \
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infile, outfile, 1 + ' ', 077 + ' ' + 1); \
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return (1); \
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} while (0)
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/*
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* `i' is used to avoid writing out all the characters
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* at the end of the file.
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*/
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p = buf;
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if ((i = DEC(*p)) <= 0)
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break;
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for (++p; i > 0; p += 4, i -= 3)
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if (i >= 3) {
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if (!(IS_DEC(*p) && IS_DEC(*(p + 1)) &&
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IS_DEC(*(p + 2)) && IS_DEC(*(p + 3))))
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OUT_OF_RANGE;
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ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
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putc(ch, outfp);
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ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
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putc(ch, outfp);
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ch = DEC(p[2]) << 6 | DEC(p[3]);
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putc(ch, outfp);
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}
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else {
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if (i >= 1) {
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if (!(IS_DEC(*p) && IS_DEC(*(p + 1))))
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OUT_OF_RANGE;
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ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
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putc(ch, outfp);
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}
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if (i >= 2) {
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if (!(IS_DEC(*(p + 1)) &&
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IS_DEC(*(p + 2))))
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OUT_OF_RANGE;
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ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
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putc(ch, outfp);
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}
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if (i >= 3) {
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if (!(IS_DEC(*(p + 2)) &&
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IS_DEC(*(p + 3))))
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OUT_OF_RANGE;
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ch = DEC(p[2]) << 6 | DEC(p[3]);
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putc(ch, outfp);
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}
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}
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}
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switch (getline(buf, sizeof(buf))) {
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case 0: return (0);
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case 1: return (1);
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default: return (checkend(buf, "end", "no \"end\" line"));
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}
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}
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static int
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base64_decode(void)
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{
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int n;
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char inbuf[MAXPATHLEN+1];
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unsigned char outbuf[MAXPATHLEN * 4];
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for (;;) {
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switch (getline(inbuf, sizeof(inbuf))) {
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case 0: return (0);
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case 1: return (1);
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}
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n = b64_pton(inbuf, outbuf, sizeof(outbuf));
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if (n < 0)
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break;
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fwrite(outbuf, 1, n, outfp);
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}
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return (checkend(inbuf, "====",
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"error decoding base64 input stream"));
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}
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static void
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usage(void)
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{
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(void)fprintf(stderr,
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"usage: uudecode [-cimprs] [file ...]\n"
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" uudecode [-i] -o output_file [file]\n"
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" b64decode [-cimprs] [file ...]\n"
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" b64decode [-i] -o output_file [file]\n");
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exit(1);
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}
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