/*      $NetBSD: uudecode.c,v 1.28 2013/01/28 19:50:30 apb Exp $        */

/*-
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#if !defined(lint)
__COPYRIGHT("@(#) Copyright (c) 1983, 1993\
 The Regents of the University of California.  All rights reserved.");
#if 0
static char sccsid[] = "@(#)uudecode.c  8.2 (Berkeley) 4/2/94";
#endif
__RCSID("$NetBSD: uudecode.c,v 1.28 2013/01/28 19:50:30 apb Exp $");
#endif /* not lint */

/*
 * uudecode [file ...]
 *
 * create the specified file, decoding as you go.
 * used with uuencode.
 */
#include <sys/param.h>
#include <sys/stat.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifndef NO_BASE64
#include <netinet/in.h>
#include <resolv.h>
#endif

static int decode(char *);
__dead static void usage(void);
static int checkend(const char *, const char *, const char *);
static int base64_decode(void);

static int base64;
static const char *inputname;

int
main(int argc, char *argv[])
{
        int ch, rval;
        char *outputname = NULL;

        setlocale(LC_ALL, "");
        setprogname(argv[0]);

        while ((ch = getopt(argc, argv, "mo:p")) != -1)
                switch (ch) {
                case 'm':
                        base64 = 1;
                        break;
                case 'o':
                        outputname = optarg;
                        break;
                case 'p':
                        outputname = __UNCONST("/dev/stdout");
                        break;
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (*argv) {
                rval = 0;
                do {
                        if (!freopen(inputname = *argv, "r", stdin)) {
                                warn("%s", *argv);
                                rval = 1;
                                continue;
                        }
                        rval |= decode(outputname);
                } while (*++argv);
        } else {
                inputname = "stdin";
                rval = decode(outputname);
        }
        exit(rval);
}

/*
 * Decode one file from stdin.  If outputname is not NULL
 * then it overrides the file name embedded in the input data.
 */
static int
decode(char *outputname)
{
        struct passwd *pw;
        int n;
        char ch, *p;
        int n1;
        long mode;
        char *fn;
        char buf[MAXPATHLEN];

        /* search for header line */
        for (;;) {
                if (!fgets(buf, sizeof(buf), stdin)) {
                        warnx("%s: no \"%s\" line", inputname, base64 ? 
                                        "begin-base64" : "begin");
                        return(1);
                }
                p = buf;
                if (strncmp(p, "begin-base64", 12) == 0) {
                        base64 = 1;
                        p += 13;
                        break;
                } else if (strncmp(p, "begin", 5) == 0)  {
                        p += 6;
                        break;
                } else
                        continue;
        } 

        /* must be followed by an octal mode and a space */
        mode = strtol(p, &fn, 8);
        if (fn == (p) || !isspace((unsigned char)*fn) || mode==LONG_MIN || mode==LONG_MAX)
        {
                warnx("%s: invalid mode on \"%s\" line", inputname,
                        base64 ? "begin-base64" : "begin");
                return(1);
        }
        /* skip whitespace for file name */
        while (*fn && isspace((unsigned char)*fn)) fn++;
        if (*fn == 0) {
                warnx("%s: no filename on \"%s\" line", inputname,
                        base64 ? "begin-base64" : "begin");
                return(1);
        }
        /* zap newline */
        for (p = fn; *p && *p != '\n'; p++) 
                ;
        if (*p) *p = 0;

        /* outputname overrides fn */
        if (outputname)
                fn = outputname;
        
        /* handle ~user/file format */
        if (*fn == '~') {
                if (!(p = strchr(fn, '/'))) {
                        warnx("%s: illegal ~user.", inputname);
                        return(1);
                }
                *p++ = '\0';
                if (!(pw = getpwnam(fn + 1))) {
                        warnx("%s: no user %s.", inputname, buf);
                        return(1);
                }
                n = strlen(pw->pw_dir);
                n1 = strlen(p);
                if (n + n1 + 2 > MAXPATHLEN) {
                        warnx("%s: path too long.", inputname);
                        return(1);
                }
                /* make space at beginning of buf by moving end of pathname */
                memmove(buf + n + 1, p, n1 + 1);
                memmove(buf, pw->pw_dir, n);
                buf[n] = '/';
                fn = buf;
        }

        if (strcmp(fn, "/dev/stdout") == 0 || strcmp(fn, "-") == 0) {
                /*
                 * POSIX.1-2008 says that both "-" and "/dev/stdout"
                 * refer to standard output when they appear in the file
                 * header, but only "/dev/stdout" refers to standard
                 * output when it appears as the argument to the "-o"
                 * command line option.
                 *
                 * We handle both special names, regardless of whether
                 * they came from the "-o" option or from the header of
                 * the input stream.
                 */
        } else {
                /*
                 * Create output file, and set its mode.  POSIX.1-2008
                 * requires the mode to be used exactly, ignoring the
                 * umask and anything else, but we mask it with 0666.
                 */
                if (freopen(fn, "w", stdout) == NULL ||
                    fchmod(fileno(stdout), mode & 0666) != 0) { 
                        warn("%s: %s", fn, inputname);
                        return(1);
                }
        }

        if (base64)
                return base64_decode();
        else {
                /* for each input line */
                for (;;) {
                        if (!fgets(p = buf, sizeof(buf), stdin)) {
                                warnx("%s: short file.", inputname);
                                return(1);
                        }
#define DEC(c)  (((c) - ' ') & 077)             /* single character decode */
                        /*
                        * `n' is used to avoid writing out all the characters
                        * at the end of the file.
                        */
                        if ((n = DEC(*p)) <= 0)
                                break;
                        for (++p; n > 0; p += 4, n -= 3)
                                if (n >= 3) {
                                        ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
                                        putchar(ch);
                                        ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
                                        putchar(ch);
                                        ch = DEC(p[2]) << 6 | DEC(p[3]);
                                        putchar(ch);
                                }
                                else {
                                        if (n >= 1) {
                                                ch = DEC(p[0]) << 2 | DEC(p[1]) >> 4;
                                                putchar(ch);
                                        }
                                        if (n >= 2) {
                                                ch = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
                                                putchar(ch);
                                        }
                                        if (n >= 3) {
                                                ch = DEC(p[2]) << 6 | DEC(p[3]);
                                                putchar(ch);
                                        }
                                }
                }
                if (!fgets(buf, sizeof(buf), stdin) || strcmp(buf, "end\n")) {
                        warnx("%s: no \"end\" line.", inputname);
                        return(1);
                }
                return(0);
        }
}

static int
checkend(const char *ptr, const char *end, const char *msg)
{
        size_t n;

        n = strlen(end);
        if (strncmp(ptr, end, n) != 0 ||
            strspn(ptr + n, "\t\r\n") != strlen(ptr + n)) {
                warnx("%s", msg); 
                return (1);
        }
        return (0);
}

static int
base64_decode(void)
{
        int n;
        char inbuf[MAXPATHLEN];
        unsigned char outbuf[MAXPATHLEN * 4];

        for (;;) {
                if (!fgets(inbuf, sizeof(inbuf), stdin)) {
                        warnx("%s: short file.", inputname);
                        return (1);
                }
#ifdef NO_BASE64
                warnx("%s: base64 decoding is not supported", inputname);
                return (1);
#else
                n = b64_pton(inbuf, outbuf, sizeof(outbuf));
#endif
                if (n < 0)
                        break;
                fwrite(outbuf, 1, n, stdout);
        }
        return (checkend(inbuf, "====",
                        "error decoding base64 input stream"));
}

static void
usage(void)
{
        (void)fprintf(stderr,
                      "usage: %s [-m] [-p | -o outfile] [encoded-file ...]\n",
                      getprogname());
        exit(1);
}