LXR busybox/coreutils/uudecode.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * Copyright 2003, Glenn McGrath
   4 *
   5 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   6 *
   7 * Based on specification from
   8 * http://www.opengroup.org/onlinepubs/007904975/utilities/uuencode.html
   9 *
  10 * Bugs: the spec doesn't mention anything about "`\n`\n" prior to the
  11 * "end" line
  12 */
  13//config:config UUDECODE
  14//config:       bool "uudecode (5.8 kb)"
  15//config:       default y
  16//config:       help
  17//config:       uudecode is used to decode a uuencoded file.
  18
  19//applet:IF_UUDECODE(APPLET(uudecode, BB_DIR_USR_BIN, BB_SUID_DROP))
  20
  21//kbuild:lib-$(CONFIG_UUDECODE) += uudecode.o
  22
  23//usage:#define uudecode_trivial_usage
  24//usage:       "[-o OUTFILE] [INFILE]"
  25//usage:#define uudecode_full_usage "\n\n"
  26//usage:       "Uudecode a file\n"
  27//usage:       "Finds OUTFILE in uuencoded source unless -o is given"
  28//usage:
  29//usage:#define uudecode_example_usage
  30//usage:       "$ uudecode -o busybox busybox.uu\n"
  31//usage:       "$ ls -l busybox\n"
  32//usage:       "-rwxr-xr-x   1 ams      ams        245264 Jun  7 21:35 busybox\n"
  33
  34#include "libbb.h"
  35
  36#if ENABLE_UUDECODE
  37static void FAST_FUNC read_stduu(FILE *src_stream, FILE *dst_stream, int flags UNUSED_PARAM)
  38{
  39        char *line;
  40
  41        for (;;) {
  42                int encoded_len, str_len;
  43                char *line_ptr, *dst;
  44                size_t line_len;
  45
  46                line_len = 64 * 1024;
  47                line = xmalloc_fgets_str_len(src_stream, "\n", &line_len);
  48                if (!line)
  49                        break;
  50                /* Handle both Unix and MSDOS text.
  51                 * Note: space should not be trimmed, some encoders use it instead of "`"
  52                 * for padding of last incomplete 4-char block.
  53                 */
  54                str_len = line_len;
  55                while (--str_len >= 0
  56                 && (line[str_len] == '\n' || line[str_len] == '\r')
  57                ) {
  58                        line[str_len] = '\0';
  59                }
  60
  61                if (strcmp(line, "end") == 0) {
  62                        return; /* the only non-error exit */
  63                }
  64
  65                line_ptr = line;
  66                while (*line_ptr) {
  67                        *line_ptr = (*line_ptr - 0x20) & 0x3f;
  68                        line_ptr++;
  69                }
  70                str_len = line_ptr - line;
  71
  72                encoded_len = line[0] * 4 / 3;
  73                /* Check that line is not too short. (we tolerate
  74                 * overly _long_ line to accommodate possible extra "`").
  75                 * Empty line case is also caught here. */
  76                if (str_len <= encoded_len) {
  77                        break; /* go to bb_error_msg_and_die("short file"); */
  78                }
  79                if (encoded_len <= 0) {
  80                        /* Ignore the "`\n" line, why is it even in the encode file ? */
  81                        free(line);
  82                        continue;
  83                }
  84                if (encoded_len > 60) {
  85                        bb_error_msg_and_die("line too long");
  86                }
  87
  88                dst = line;
  89                line_ptr = line + 1;
  90                do {
  91                        /* Merge four 6 bit chars to three 8 bit chars */
  92                        *dst++ = line_ptr[0] << 2 | line_ptr[1] >> 4;
  93                        encoded_len--;
  94                        if (encoded_len == 0) {
  95                                break;
  96                        }
  97
  98                        *dst++ = line_ptr[1] << 4 | line_ptr[2] >> 2;
  99                        encoded_len--;
 100                        if (encoded_len == 0) {
 101                                break;
 102                        }
 103
 104                        *dst++ = line_ptr[2] << 6 | line_ptr[3];
 105                        line_ptr += 4;
 106                        encoded_len -= 2;
 107                } while (encoded_len > 0);
 108                fwrite(line, 1, dst - line, dst_stream);
 109                free(line);
 110        }
 111        bb_error_msg_and_die("short file");
 112}
 113#endif
 114
 115#if ENABLE_UUDECODE
 116int uudecode_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 117int uudecode_main(int argc UNUSED_PARAM, char **argv)
 118{
 119        FILE *src_stream;
 120        char *outname = NULL;
 121        char *line;
 122
 123        getopt32(argv, "^" "o:" "\0" "?1"/* 1 arg max*/, &outname);
 124        argv += optind;
 125
 126        if (!argv[0])
 127                *--argv = (char*)"-";
 128        src_stream = xfopen_stdin(argv[0]);
 129
 130        /* Search for the start of the encoding */
 131        while ((line = xmalloc_fgetline(src_stream)) != NULL) {
 132                void FAST_FUNC (*decode_fn_ptr)(FILE *src, FILE *dst, int flags);
 133                char *line_ptr;
 134                FILE *dst_stream;
 135                int mode;
 136
 137                if (is_prefixed_with(line, "begin-base64 ")) {
 138                        line_ptr = line + 13;
 139                        decode_fn_ptr = read_base64;
 140                } else if (is_prefixed_with(line, "begin ")) {
 141                        line_ptr = line + 6;
 142                        decode_fn_ptr = read_stduu;
 143                } else {
 144                        free(line);
 145                        continue;
 146                }
 147
 148                /* begin line found. decode and exit */
 149                mode = bb_strtou(line_ptr, NULL, 8);
 150                if (outname == NULL) {
 151                        outname = strchr(line_ptr, ' ');
 152                        if (!outname)
 153                                break;
 154                        outname++;
 155                        trim(outname); /* remove trailing space (and '\r' for DOS text) */
 156                        if (!outname[0])
 157                                break;
 158                }
 159                dst_stream = stdout;
 160                if (NOT_LONE_DASH(outname)) {
 161                        dst_stream = xfopen_for_write(outname);
 162                        fchmod(fileno(dst_stream), mode & (S_IRWXU | S_IRWXG | S_IRWXO));
 163                }
 164                free(line);
 165                decode_fn_ptr(src_stream, dst_stream, /*flags:*/ BASE64_FLAG_UU_STOP + BASE64_FLAG_NO_STOP_CHAR);
 166                /* fclose_if_not_stdin(src_stream); - redundant */
 167                return EXIT_SUCCESS;
 168        }
 169        bb_error_msg_and_die("no 'begin' line");
 170}
 171#endif
 172
 173//applet:IF_BASE64(APPLET(base64, BB_DIR_BIN, BB_SUID_DROP))
 174
 175//kbuild:lib-$(CONFIG_BASE64) += uudecode.o
 176
 177//config:config BASE64
 178//config:       bool "base64 (4.9 kb)"
 179//config:       default y
 180//config:       help
 181//config:       Base64 encode and decode
 182
 183//usage:#define base64_trivial_usage
 184//usage:        "[-d] [FILE]"
 185//usage:#define base64_full_usage "\n\n"
 186//usage:       "Base64 encode or decode FILE to standard output"
 187//usage:     "\n        -d      Decode data"
 188////usage:     "\n      -w COL  Wrap lines at COL (default 76, 0 disables)"
 189////usage:     "\n      -i      When decoding, ignore non-alphabet characters"
 190
 191#if ENABLE_BASE64
 192int base64_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 193int base64_main(int argc UNUSED_PARAM, char **argv)
 194{
 195        FILE *src_stream;
 196        unsigned opts;
 197
 198        opts = getopt32(argv, "^" "d" "\0" "?1"/* 1 arg max*/);
 199        argv += optind;
 200
 201        if (!argv[0])
 202                *--argv = (char*)"-";
 203        src_stream = xfopen_stdin(argv[0]);
 204        if (opts) {
 205                read_base64(src_stream, stdout, /*flags:*/ (char)EOF);
 206        } else {
 207                enum {
 208                        SRC_BUF_SIZE = 76/4*3,  /* This *MUST* be a multiple of 3 */
 209                        DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
 210                };
 211                char src_buf[SRC_BUF_SIZE];
 212                char dst_buf[DST_BUF_SIZE + 1];
 213                int src_fd = fileno(src_stream);
 214                while (1) {
 215                        size_t size = full_read(src_fd, src_buf, SRC_BUF_SIZE);
 216                        if (!size)
 217                                break;
 218                        if ((ssize_t)size < 0)
 219                                bb_perror_msg_and_die(bb_msg_read_error);
 220                        /* Encode the buffer we just read in */
 221                        bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
 222                        xwrite(STDOUT_FILENO, dst_buf, 4 * ((size + 2) / 3));
 223                        bb_putchar('\n');
 224                        fflush(stdout);
 225                }
 226        }
 227
 228        fflush_stdout_and_exit(EXIT_SUCCESS);
 229}
 230#endif
 231
 232/* Test script.
 233Put this into an empty dir with busybox binary, an run.
 234
 235#!/bin/sh
 236test -x busybox || { echo "No ./busybox?"; exit; }
 237ln -sf busybox uudecode
 238ln -sf busybox uuencode
 239>A_null
 240echo -n A >A
 241echo -n AB >AB
 242echo -n ABC >ABC
 243echo -n ABCD >ABCD
 244echo -n ABCDE >ABCDE
 245echo -n ABCDEF >ABCDEF
 246cat busybox >A_bbox
 247for f in A*; do
 248    echo uuencode $f
 249    ./uuencode    $f <$f >u_$f
 250    ./uuencode -m $f <$f >m_$f
 251done
 252mkdir unpk_u unpk_m 2>/dev/null
 253for f in u_*; do
 254    ./uudecode <$f -o unpk_u/${f:2}
 255    diff -a ${f:2} unpk_u/${f:2} >/dev/null 2>&1
 256    echo uudecode $f: $?
 257done
 258for f in m_*; do
 259    ./uudecode <$f -o unpk_m/${f:2}
 260    diff -a ${f:2} unpk_m/${f:2} >/dev/null 2>&1
 261    echo uudecode $f: $?
 262done
 263*/
 264