[3320] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Copyright 2003, Glenn McGrath
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| 4 | * Copyright 2006, Rob Landley <rob@landley.net>
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| 5 | * Copyright 2010, Denys Vlasenko
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| 6 | *
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| 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 8 | */
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| 9 |
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| 10 | #include "libbb.h"
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| 11 |
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| 12 | /* Conversion table. for base 64 */
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| 13 | const char bb_uuenc_tbl_base64[65 + 2] ALIGN1 = {
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| 14 | 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
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| 15 | 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
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| 16 | 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
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| 17 | 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
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| 18 | 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
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| 19 | 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
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| 20 | 'w', 'x', 'y', 'z', '0', '1', '2', '3',
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| 21 | '4', '5', '6', '7', '8', '9', '+', '/',
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| 22 | '=' /* termination character */,
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| 23 | '\n', '\0' /* needed for uudecode.c */
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| 24 | };
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| 25 |
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| 26 | const char bb_uuenc_tbl_std[65] ALIGN1 = {
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| 27 | '`', '!', '"', '#', '$', '%', '&', '\'',
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| 28 | '(', ')', '*', '+', ',', '-', '.', '/',
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| 29 | '0', '1', '2', '3', '4', '5', '6', '7',
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| 30 | '8', '9', ':', ';', '<', '=', '>', '?',
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| 31 | '@', 'A', 'B', 'C', 'D', 'E', 'F', 'G',
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| 32 | 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O',
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| 33 | 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
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| 34 | 'X', 'Y', 'Z', '[', '\\', ']', '^', '_',
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| 35 | '`' /* termination character */
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| 36 | };
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| 37 |
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| 38 | /*
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| 39 | * Encode bytes at S of length LENGTH to uuencode or base64 format and place it
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| 40 | * to STORE. STORE will be 0-terminated, and must point to a writable
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| 41 | * buffer of at least 1+BASE64_LENGTH(length) bytes.
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| 42 | * where BASE64_LENGTH(len) = (4 * ((LENGTH + 2) / 3))
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| 43 | */
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| 44 | void FAST_FUNC bb_uuencode(char *p, const void *src, int length, const char *tbl)
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| 45 | {
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| 46 | const unsigned char *s = src;
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| 47 |
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| 48 | /* Transform the 3x8 bits to 4x6 bits */
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| 49 | while (length > 0) {
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| 50 | unsigned s1, s2;
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| 51 |
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| 52 | /* Are s[1], s[2] valid or should be assumed 0? */
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| 53 | s1 = s2 = 0;
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| 54 | length -= 3; /* can be >=0, -1, -2 */
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| 55 | if (length >= -1) {
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| 56 | s1 = s[1];
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| 57 | if (length >= 0)
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| 58 | s2 = s[2];
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| 59 | }
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| 60 | *p++ = tbl[s[0] >> 2];
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| 61 | *p++ = tbl[((s[0] & 3) << 4) + (s1 >> 4)];
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| 62 | *p++ = tbl[((s1 & 0xf) << 2) + (s2 >> 6)];
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| 63 | *p++ = tbl[s2 & 0x3f];
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| 64 | s += 3;
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| 65 | }
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| 66 | /* Zero-terminate */
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| 67 | *p = '\0';
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| 68 | /* If length is -2 or -1, pad last char or two */
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| 69 | while (length) {
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| 70 | *--p = tbl[64];
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| 71 | length++;
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| 72 | }
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| 73 | }
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| 74 |
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| 75 | /*
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| 76 | * Decode base64 encoded stream.
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| 77 | * Can stop on EOF, specified char, or on uuencode-style "====" line:
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| 78 | * flags argument controls it.
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| 79 | */
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| 80 | void FAST_FUNC read_base64(FILE *src_stream, FILE *dst_stream, int flags)
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| 81 | {
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| 82 | /* Note that EOF _can_ be passed as exit_char too */
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| 83 | #define exit_char ((int)(signed char)flags)
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| 84 | #define uu_style_end (flags & BASE64_FLAG_UU_STOP)
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| 85 |
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| 86 | int term_count = 0;
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| 87 |
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| 88 | while (1) {
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| 89 | unsigned char translated[4];
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| 90 | int count = 0;
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| 91 |
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| 92 | /* Process one group of 4 chars */
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| 93 | while (count < 4) {
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| 94 | char *table_ptr;
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| 95 | int ch;
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| 96 |
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| 97 | /* Get next _valid_ character.
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| 98 | * bb_uuenc_tbl_base64[] contains this string:
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| 99 | * 0 1 2 3 4 5 6
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| 100 | * 012345678901234567890123456789012345678901234567890123456789012345
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| 101 | * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
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| 102 | */
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| 103 | do {
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| 104 | ch = fgetc(src_stream);
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| 105 | if (ch == exit_char && count == 0)
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| 106 | return;
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| 107 | if (ch == EOF)
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| 108 | bb_error_msg_and_die("truncated base64 input");
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| 109 | table_ptr = strchr(bb_uuenc_tbl_base64, ch);
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| 110 | //TODO: add BASE64_FLAG_foo to die on bad char?
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| 111 | //Note that then we may need to still allow '\r' (for mail processing)
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| 112 | } while (!table_ptr);
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| 113 |
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| 114 | /* Convert encoded character to decimal */
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| 115 | ch = table_ptr - bb_uuenc_tbl_base64;
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| 116 |
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| 117 | if (ch == 65 /* '\n' */) {
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| 118 | /* Terminating "====" line? */
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| 119 | if (uu_style_end && term_count == 4)
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| 120 | return; /* yes */
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| 121 | term_count = 0;
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| 122 | continue;
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| 123 | }
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| 124 | /* ch is 64 if char was '=', otherwise 0..63 */
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| 125 | translated[count] = ch & 63; /* 64 -> 0 */
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| 126 | if (ch == 64) {
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| 127 | term_count++;
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| 128 | break;
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| 129 | }
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| 130 | count++;
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| 131 | term_count = 0;
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| 132 | }
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| 133 |
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| 134 | /* Merge 6 bit chars to 8 bit.
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| 135 | * count can be < 4 when we decode the tail:
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| 136 | * "eQ==" -> "y", not "y NUL NUL"
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| 137 | */
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| 138 | if (count > 1)
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| 139 | fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
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| 140 | if (count > 2)
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| 141 | fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
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| 142 | if (count > 3)
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| 143 | fputc(translated[2] << 6 | translated[3], dst_stream);
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| 144 | } /* while (1) */
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| 145 | }
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