source: MondoRescue/branches/3.3/mindi-busybox/coreutils/uudecode.c@ 3865

/* vi: set sw=4 ts=4: */
/*
 * Copyright 2003, Glenn McGrath
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 *
 * Based on specification from
 * http://www.opengroup.org/onlinepubs/007904975/utilities/uuencode.html
 *
 * Bugs: the spec doesn't mention anything about "`\n`\n" prior to the
 * "end" line
 */

//usage:#define uudecode_trivial_usage
//usage:       "[-o OUTFILE] [INFILE]"
//usage:#define uudecode_full_usage "\n\n"
//usage:       "Uudecode a file\n"
//usage:       "Finds OUTFILE in uuencoded source unless -o is given"
//usage:
//usage:#define uudecode_example_usage
//usage:       "$ uudecode -o busybox busybox.uu\n"
//usage:       "$ ls -l busybox\n"
//usage:       "-rwxr-xr-x   1 ams      ams        245264 Jun  7 21:35 busybox\n"

#include "libbb.h"

#if ENABLE_UUDECODE
static void FAST_FUNC read_stduu(FILE *src_stream, FILE *dst_stream, int flags UNUSED_PARAM)
{
    char *line;

    for (;;) {
        int encoded_len, str_len;
        char *line_ptr, *dst;
        size_t line_len;

        line_len = 64 * 1024;
        line = xmalloc_fgets_str_len(src_stream, "\n", &line_len);
        if (!line)
            break;
        /* Handle both Unix and MSDOS text, and stray trailing spaces */
        str_len = line_len;
        while (--str_len >= 0 && isspace(line[str_len]))
            line[str_len] = '\0';

        if (strcmp(line, "end") == 0) {
            return; /* the only non-error exit */
        }

        line_ptr = line;
        while (*line_ptr) {
            *line_ptr = (*line_ptr - 0x20) & 0x3f;
            line_ptr++;
        }
        str_len = line_ptr - line;

        encoded_len = line[0] * 4 / 3;
        /* Check that line is not too short. (we tolerate
         * overly _long_ line to accommodate possible extra '`').
         * Empty line case is also caught here. */
        if (str_len <= encoded_len) {
            break; /* go to bb_error_msg_and_die("short file"); */
        }
        if (encoded_len <= 0) {
            /* Ignore the "`\n" line, why is it even in the encode file ? */
            free(line);
            continue;
        }
        if (encoded_len > 60) {
            bb_error_msg_and_die("line too long");
        }

        dst = line;
        line_ptr = line + 1;
        do {
            /* Merge four 6 bit chars to three 8 bit chars */
            *dst++ = line_ptr[0] << 2 | line_ptr[1] >> 4;
            encoded_len--;
            if (encoded_len == 0) {
                break;
            }

            *dst++ = line_ptr[1] << 4 | line_ptr[2] >> 2;
            encoded_len--;
            if (encoded_len == 0) {
                break;
            }

            *dst++ = line_ptr[2] << 6 | line_ptr[3];
            line_ptr += 4;
            encoded_len -= 2;
        } while (encoded_len > 0);
        fwrite(line, 1, dst - line, dst_stream);
        free(line);
    }
    bb_error_msg_and_die("short file");
}
#endif

#if ENABLE_UUDECODE
int uudecode_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int uudecode_main(int argc UNUSED_PARAM, char **argv)
{
    FILE *src_stream;
    char *outname = NULL;
    char *line;

    opt_complementary = "?1"; /* 1 argument max */
    getopt32(argv, "o:", &outname);
    argv += optind;

    if (!argv[0])
        *--argv = (char*)"-";
    src_stream = xfopen_stdin(argv[0]);

    /* Search for the start of the encoding */
    while ((line = xmalloc_fgetline(src_stream)) != NULL) {
        void FAST_FUNC (*decode_fn_ptr)(FILE *src, FILE *dst, int flags);
        char *line_ptr;
        FILE *dst_stream;
        int mode;

        if (is_prefixed_with(line, "begin-base64 ")) {
            line_ptr = line + 13;
            decode_fn_ptr = read_base64;
        } else if (is_prefixed_with(line, "begin ")) {
            line_ptr = line + 6;
            decode_fn_ptr = read_stduu;
        } else {
            free(line);
            continue;
        }

        /* begin line found. decode and exit */
        mode = bb_strtou(line_ptr, NULL, 8);
        if (outname == NULL) {
            outname = strchr(line_ptr, ' ');
            if (!outname)
                break;
            outname++;
            trim(outname); /* remove trailing space (and '\r' for DOS text) */
            if (!outname[0])
                break;
        }
        dst_stream = stdout;
        if (NOT_LONE_DASH(outname)) {
            dst_stream = xfopen_for_write(outname);
            fchmod(fileno(dst_stream), mode & (S_IRWXU | S_IRWXG | S_IRWXO));
        }
        free(line);
        decode_fn_ptr(src_stream, dst_stream, /*flags:*/ BASE64_FLAG_UU_STOP + BASE64_FLAG_NO_STOP_CHAR);
        /* fclose_if_not_stdin(src_stream); - redundant */
        return EXIT_SUCCESS;
    }
    bb_error_msg_and_die("no 'begin' line");
}
#endif

//applet:IF_BASE64(APPLET(base64, BB_DIR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_BASE64) += uudecode.o

//config:config BASE64
//config:   bool "base64"
//config:   default y
//config:   help
//config:     Base64 encode and decode

//usage:#define base64_trivial_usage
//usage:    "[-d] [FILE]"
//usage:#define base64_full_usage "\n\n"
//usage:       "Base64 encode or decode FILE to standard output"
//usage:     "\n    -d  Decode data"
////usage:     "\n  -w COL  Wrap lines at COL (default 76, 0 disables)"
////usage:     "\n  -i  When decoding, ignore non-alphabet characters"

#if ENABLE_BASE64
int base64_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int base64_main(int argc UNUSED_PARAM, char **argv)
{
    FILE *src_stream;
    unsigned opts;

    opt_complementary = "?1"; /* 1 argument max */
    opts = getopt32(argv, "d");
    argv += optind;

    if (!argv[0])
        *--argv = (char*)"-";
    src_stream = xfopen_stdin(argv[0]);
    if (opts) {
        read_base64(src_stream, stdout, /*flags:*/ (char)EOF);
    } else {
        enum {
            SRC_BUF_SIZE = 76/4*3,  /* This *MUST* be a multiple of 3 */
            DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
        };
        char src_buf[SRC_BUF_SIZE];
        char dst_buf[DST_BUF_SIZE + 1];
        int src_fd = fileno(src_stream);
        while (1) {
            size_t size = full_read(src_fd, src_buf, SRC_BUF_SIZE);
            if (!size)
                break;
            if ((ssize_t)size < 0)
                bb_perror_msg_and_die(bb_msg_read_error);
            /* Encode the buffer we just read in */
            bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
            xwrite(STDOUT_FILENO, dst_buf, 4 * ((size + 2) / 3));
            bb_putchar('\n');
            fflush(stdout);
        }
    }

    fflush_stdout_and_exit(EXIT_SUCCESS);
}
#endif

/* Test script.
Put this into an empty dir with busybox binary, an run.

#!/bin/sh
test -x busybox || { echo "No ./busybox?"; exit; }
ln -sf busybox uudecode
ln -sf busybox uuencode
>A_null
echo -n A >A
echo -n AB >AB
echo -n ABC >ABC
echo -n ABCD >ABCD
echo -n ABCDE >ABCDE
echo -n ABCDEF >ABCDEF
cat busybox >A_bbox
for f in A*; do
    echo uuencode $f
    ./uuencode    $f <$f >u_$f
    ./uuencode -m $f <$f >m_$f
done
mkdir unpk_u unpk_m 2>/dev/null
for f in u_*; do
    ./uudecode <$f -o unpk_u/${f:2}
    diff -a ${f:2} unpk_u/${f:2} >/dev/null 2>&1
    echo uudecode $f: $?
done
for f in m_*; do
    ./uudecode <$f -o unpk_m/${f:2}
    diff -a ${f:2} unpk_m/${f:2} >/dev/null 2>&1
    echo uudecode $f: $?
done
*/