/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

/*      Copyright 2004 Sun Microsystems, Inc.  All rights reserved. */
/*      Use is subject to license terms. */

/*
 * uudecode [-o outfile | -p] [input]
 *
 * create the specified file, decoding as you go.
 * used with uuencode.
 */
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <pwd.h>
#include <string.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <locale.h>
#include <nl_types.h>
#include <langinfo.h>
#include <iconv.h>
#include <limits.h>
#include <errno.h>
#include <ctype.h>
#include <signal.h>
#include <stdarg.h>

#define BUFSIZE 90      /* must be a multiple of 3 */

#define TABLE_SIZE      0x40

#define isvalid(octet)  (octet <= 0x40)

/*
 * base64 decoding table
 */
/* BEGIN CSTYLED */
static char base64tab[] = {
        '\377', '\377', '\377', '\377', '\377', '\377', '\377', '\377',
        '\377', '\377', '\377', '\377', '\377', '\377', '\377', '\377',
        '\377', '\377', '\377', '\377', '\377', '\377', '\377', '\377',
        '\377', '\377', '\377', '\377', '\377', '\377', '\377', '\377',
        '\377', '\377', '\377', '\377', '\377', '\377', '\377', '\377',
        '\377', '\377', '\377',     62, '\377', '\377', '\377',     63,
            52,     53,     54,     55,     56,     57,     58,     59,
            60,     61, '\377', '\377', '\377', '\377', '\377', '\377',
        '\377',      0,      1,      2,      3,      4,      5,      6,
             7,      8,      9,     10,     11,     12,     13,     14,
            15,     16,     17,     18,     19,     20,     21,     22,
            23,     24,     25, '\377', '\377', '\377', '\377', '\377',
        '\377',     26,     27,     28,     29,     30,     31,     32,
            33,     34,     35,     36,     37,     38,     39,     40,
            41,     42,     43,     44,     45,     46,     47,     48,
            49,     50,     51, '\377', '\377', '\377', '\377', '\377'
};
/* END CSTYLED */

static char     decode_table[UCHAR_MAX + 1];

/* DEC is the basic 1 character decoding function (historical algorithm) */
#define DEC(c)  decode_table[c]

/* true if the character is in the base64 encoding table */
#define validbase64(c) (('A' <= (c) && (c) <= 'Z') || \
                ('a' <= (c) && (c) <= 'z') || \
                ('0' <= (c) && (c) <= '9') || \
                (c) == '+' || (c) == '/')

static void     decode(FILE *, FILE *, int);
static int      outdec(unsigned char *, unsigned char *, int);
static int      outdec64(unsigned char *, unsigned char *, int);

/* from usr/src/cmd/chmod/common.c */

void errmsg(int severity, int code, char *format, ...);

extern mode_t newmode(char *ms, mode_t new_mode, mode_t umsk,
    char *file, char *path);

static char     *prog;
static char     outfile[PATH_MAX];
static int      mode_err = 0;   /* mode conversion error flag */

int
main(int argc, char **argv)
{
        FILE *in, *out;
        int pipeout = 0;
        int oflag = 0;
        int i;
        mode_t mode, p_umask;
        char dest[PATH_MAX];
        char modebits[1024];
        char buf[LINE_MAX];
        int     c, errflag = 0;
        struct stat sbuf;
        int base64flag = 0;

        prog = argv[0];
        (void) signal(SIGPIPE, SIG_DFL);
        bzero(dest, sizeof (dest));
        outfile[0] = '\0';

        /* Set locale environment variables local definitions */
        (void) setlocale(LC_ALL, "");
#if !defined(TEXT_DOMAIN)       /* Should be defined by cc -D */
#define TEXT_DOMAIN "SYS_TEST"  /* Use this only if it wasn't */
#endif
        (void) textdomain(TEXT_DOMAIN);
        p_umask = umask((mode_t)0);

        while ((c = getopt(argc, argv, "o:p")) != EOF) {
                switch (c) {
                case 'o':
                        oflag++;
                        (void) strncpy(outfile, optarg, sizeof (outfile));
                        break;
                case 'p':
                        pipeout++;
                        break;
                default:
                case '?':
                        errflag++;
                        break;
                }
        }
        argc -= optind;
        argv = &argv[optind];

        /* optional input arg */
        if (argc > 0) {
                if ((in = fopen(*argv, "r")) == NULL) {
                        perror(*argv);
                        exit(1);
                }
                argv++; argc--;
        } else {
                in = stdin;
                errno = 0;
                if (fstat(fileno(in), &sbuf) < 0) {
                        perror("stdin");
                        exit(1);
                }
        }

        if ((argc > 0) || errflag || (oflag && pipeout)) {
                (void) fprintf(stderr,
                    gettext("Usage: %s [-o outfile | -p] [infile]\n"), prog);
                exit(2);
        }

        /* search for header line */
        for (;;) {
                if (fgets(buf, sizeof (buf), in) == NULL) {
                        /* suppress message if we printed a mode error */
                        if (mode_err == 0)
                                (void) fprintf(stderr,
                                    gettext("No begin line\n"));
                        exit(3);
                }
                /*
                 * the check for begin-base64 obviously needs to come
                 * first, since both algorithms' begin strings start
                 * with 'begin'.  Also verify that there is a valid
                 * octal or symbolic file mode.
                 */
                if (strncmp(buf, "begin-base64", 12) == 0) {
                        base64flag = 1;
                        mode_err = 0;
                        if ((sscanf(buf + 13, "%1023s %1023s",
                            modebits, dest) == 2) &&
                            ((sscanf(modebits, "%lo", &mode) == 1) ||
                                ((mode = newmode(modebits, 0, p_umask,
                                    "", "")) != 0) && mode_err == 0))
                                break;
                } else if (strncmp(buf, "begin", 5) == 0) {
                        base64flag = 0;
                        mode_err = 0;
                        if ((sscanf(buf + 6, "%1023s %1023s",
                            modebits, dest) == 2) &&
                            ((sscanf(modebits, "%lo", &mode) == 1) ||
                                ((mode = newmode(modebits, 0, p_umask,
                                    "", "")) != 0) && mode_err == 0))
                                break;
                }
        }

        /*
         * Now that we know the type of encoding used, we can
         * initialize the decode table.
         */
        if (base64flag == 0) {
                (void) memset(decode_table, 0xFF, sizeof (decode_table));
                for (i = 0; i <= TABLE_SIZE; i++)
                        decode_table[(unsigned char)i + 0x20] =
                            (unsigned char)i & 0x3F;
        } else
                (void) memcpy(decode_table, base64tab, sizeof (base64tab));

        /*
         * Filename specified on the command line with -o
         * overrides filename in the encoded file.
         */
        if (outfile[0] != '\0')
                (void) strncpy(dest, outfile, sizeof (dest));

        if (pipeout ||
            (dest[0] == '-' && dest[1] == '\0' && outfile[0] == '\0')) {
                out = stdout;
                bzero(outfile, sizeof (outfile));
                bzero(dest, sizeof (dest));
        } else {
                /* handle ~user/file format */
                if (dest[0] == '~') {
                        char *sl;
                        struct passwd *user;
                        char dnbuf[100];

                        sl = strchr(dest, '/');
                        if (sl == NULL) {
                                (void) fprintf(stderr,
                                    gettext("Illegal ~user\n"));
                                exit(3);
                        }
                        *sl++ = 0;
                        user = getpwnam(dest+1);
                        if (user == NULL) {
                                (void) fprintf(stderr,
                                    gettext("No such user as %s\n"), dest);
                                exit(4);
                        }
                        (void) strncpy(dnbuf, user->pw_dir, sizeof (dnbuf));
                        (void) strlcat(dnbuf, "/", sizeof (dnbuf));
                        (void) strlcat(dnbuf, sl, sizeof (dnbuf));
                        (void) strncpy(dest, dnbuf, sizeof (dest));
                }
        }
        /* if not using stdout, create file */
        if (dest[0] != '\0') {
                if ((out = fopen(dest, "w")) == NULL) {
                        perror(dest);
                        exit(4);
                }
                (void) chmod(dest, mode & 0777);
        }

        decode(in, out, base64flag);

        if (fclose(out) == EOF) {
                perror(prog);
                exit(6);
        }

        return (0);
}

/*
 * copy from in to out, decoding as you go along.
 */

static void
decode(FILE *in, FILE *out, int base64)
{
        char    inbuf[120], *ibp, *iptr;
        unsigned char   outbuf[BUFSIZE], *obp, *optr;
        int     n, octets, warned, endseen, numbase64chars;
        unsigned char chr[4], curchr, ch;
        longlong_t line;

        if (! base64) { /* use historical algorithm */
                warned = 0;
                for (line = 1; ; line++) {
                        /* for each input line */
                        if (fgets(inbuf, sizeof (inbuf), in) == NULL) {
                                (void) fprintf(stderr,
                                    gettext("No end line\n"));
                                exit(5);
                        }

                        /* Is line == 'end\n'? */
                        if (strcmp(inbuf, "end\n") == 0) {
                                break;
                        }

                        n = DEC(inbuf[0]);

                        if (n < 0)
                                continue;

                        /*
                         * Decode data lines.
                         *
                         * Note that uuencode/uudecode uses only the portable
                         * character set for encoded data and the portable
                         * character set characters must be represented in
                         * a single byte.  We use this knowledge to reuse
                         * buffer space while decoding.
                         */
                        octets = n;
                        obp = (unsigned char *) &inbuf[0];
                        ibp = &inbuf[1];
                        while (octets > 0) {
                                if ((ch = outdec((unsigned char *)obp,
                                    (unsigned char *)ibp, octets))
                                    != 0x20) {
                                        /* invalid characters where detected */
                                        if (!warned) {
                                                warned = 1;
                                                (void) fprintf(stderr,
                                                    gettext("Invalid character"
                                                        " (0x%x) on line"
                                                        " %lld\n"), ch, line);
                                        }
                                        break;
                                }
                                ibp += 4;
                                obp += 3;
                                octets -= 3;
                        }
                        /*
                         * Only write out uncorrupted lines
                         */
                        if (octets <= 0) {
                                (void) fwrite(inbuf, n, 1, out);
                        }
                }
        } else {        /* use base64 algorithm */
                endseen = numbase64chars = 0;
                optr = outbuf;
                while ((fgets(inbuf, sizeof (inbuf), in)) != NULL) {
                        /* process an input line */
                        iptr = inbuf;
                        while ((curchr = *(iptr++)) != '\0') {
                                /* decode chars */
                                if (curchr == '=') /* if end */
                                        endseen++;

                                if (validbase64(curchr))
                                        chr[numbase64chars++] = curchr;
                                /*
                                 * if we've gathered 4 base64 octets
                                 * we need to decode and output them
                                 */
                                if (numbase64chars == 4) {
                                        /*LINTED*/
                                        if (optr - outbuf > BUFSIZE - 3) {
                                                (void) fwrite(outbuf,
                                                    /*LINTED*/
                                                    (size_t)(optr - outbuf),
                                                    1, out);
                                                if (ferror(out)) {
                                                        perror(prog);
                                                        exit(6);
                                                }
                                                optr = outbuf;
                                        }
                                        octets = outdec64(optr, chr, 4);
                                        optr += octets;
                                        numbase64chars = 0;
                                }
                        }
                        /*
                         * handle any remaining base64 octets at end
                         */
                        if (endseen && numbase64chars > 0) {
                                octets = outdec64(optr, chr, numbase64chars);
                                optr += octets;
                                numbase64chars = 0;
                        }
                }
                /*
                 * if we have generated any additional output
                 * in the buffer, write it out
                 */
                if (optr != outbuf) {
                        /*LINTED*/
                        (void) fwrite(outbuf, (size_t)(optr - outbuf),
                            1, out);
                        if (ferror(out)) {
                                perror(prog);
                                exit(6);
                        }
                }

                if (endseen == 0) {
                        (void) fprintf(stderr, gettext("No end line\n"));
                        exit(5);
                }
        }
}

/*
 * historical algorithm
 *
 * output a group of 3 bytes (4 input characters).
 * the input chars are pointed to by p, they are to
 * be output to file f.  n is used to tell us not to
 * output all of them at the end of the file.
 */

static int
outdec(unsigned char *out, unsigned char *in, int n)
{
        unsigned char   b0 = DEC(*(in++));
        unsigned char   b1 = DEC(*(in++));
        unsigned char   b2 = DEC(*(in++));
        unsigned char   b3 = DEC(*in);

        if (!isvalid(b0)) {
                return (*(in-3));
        }
        if (!isvalid(b1)) {
                return (*(in-2));
        }

        *(out++) = (b0 << 2) | (b1 >> 4);

        if (n >= 2) {
                if (!isvalid(b2)) {
                        return (*(in - 1));
                }

                *(out++) = (b1 << 4) | (b2 >> 2);

                if (n >= 3) {
                        if (!isvalid(b3)) {
                                return (*in);
                        }
                        *out = (b2 << 6) | b3;
                }
        }
        return (0x20); /* a know good value */
}

/*
 * base64 algorithm
 *
 * Takes a pointer to the current position in the output buffer,
 * a pointer to the (up to) 4 byte base64 input buffer and a
 * count of the number of valid input bytes.
 *
 * Return the number of bytes placed in the output buffer
 */
static int
outdec64(unsigned char *out, unsigned char *chr, int num)
{

        unsigned char char1, char2, char3, char4;
        unsigned char *outptr = out;
        int rc = 0;

        switch (num) {
        case 0:
        case 1:         /* these are impossible */
        default:
                break;
        case 2:         /* 2 base64 bytes == 1 decoded byte */
                char1 = base64tab[chr[0]] & 0xFF;
                char2 = base64tab[chr[1]] & 0xFF;
                *(outptr++) = ((char1 << 2) & 0xFC) |
                    ((char2 >> 4) & 0x03);
                rc = 1;
                break;
        case 3:         /* 3 base64 bytes == 2 decoded bytes */
                char1 = base64tab[chr[0]] & 0xFF;
                char2 = base64tab[chr[1]] & 0xFF;
                char3 = base64tab[chr[2]] & 0xFF;
                *(outptr++) = ((char1 << 2) & 0xFC) |
                    ((char2 >> 4) & 0x03);
                *(outptr++) = ((char2 << 4) & 0xF0) |
                    ((char3 >> 2) & 0x0F);
                rc = 2;
                break;
        case 4:         /* 4 base64 bytes == 3 decoded bytes */
                char1 = base64tab[chr[0]] & 0xFF;
                char2 = base64tab[chr[1]] & 0xFF;
                char3 = base64tab[chr[2]] & 0xFF;
                char4 = base64tab[chr[3]] & 0xFF;
                *(outptr++) = ((char1 << 2) & 0xFC) |
                    ((char2 >> 4) & 0x03);
                *(outptr++) = ((char2 << 4) & 0xF0) |
                    ((char3 >> 2) & 0x0F);
                *(outptr++) = ((char3 << 6) & 0xC0) |
                    (char4 & 0x3F);
                rc = 3;
                break;
        }
        return (rc);
}

/*
 * error message routine called by newmode.
 *
 * The severity and code are ignored here.  If this routine gets
 * called, we set a global flag (which can be tested after return
 * from here) which tells us whether or not a valid mode has been
 * parsed or if we printed an error message.
 */

/*ARGSUSED*/
void
errmsg(int severity, int code, char *format, ...)
{
        va_list ap;

        va_start(ap, format);

        (void) fprintf(stderr, "uudecode: ");
        (void) fprintf(stderr, format, ap);

        va_end(ap);

        mode_err = 1;
}