1 /* $NetBSD: base64.c,v 1.3 2020/08/14 13:40:25 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2018 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Christos Zoulas. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __RCSID("$NetBSD: base64.c,v 1.3 2020/08/14 13:40:25 christos Exp $"); 34 35 #include <ctype.h> 36 #include <errno.h> 37 #include <err.h> 38 #include <stdbool.h> 39 #include <stdio.h> 40 #include <stdint.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <unistd.h> 44 45 static const char B64[] = 46 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; 47 48 static size_t 49 getinput(FILE *fin, uint8_t in[3]) 50 { 51 size_t res; 52 int c; 53 54 for (res = 0; res < 3 && (c = getc(fin)) != EOF; res++) 55 in[res] = (uint8_t)c; 56 for (size_t i = res; i < 3; i++) 57 in[i] = 0; 58 59 return res; 60 } 61 62 static int 63 putoutput(FILE *fout, uint8_t out[4], size_t len, size_t wrap, size_t *pos) 64 { 65 size_t i; 66 67 for (i = 0; i < len + 1; i++) { 68 if (out[i] >= 64) { 69 return EINVAL; 70 } 71 if (fputc(B64[out[i]], fout) == -1) 72 return errno; 73 if (++(*pos) == wrap) { 74 if (fputc('\n', fout) == -1) 75 return errno; 76 *pos = 0; 77 } 78 } 79 for (; i < 4; i++) { 80 if (fputc('=', fout) == -1) 81 return errno; 82 if (++(*pos) == wrap) { 83 if (fputc('\n', fout) == -1) 84 return errno; 85 *pos = 0; 86 } 87 } 88 89 return 0; 90 } 91 92 static void 93 encode(uint8_t out[4], uint8_t in[3]) 94 { 95 out[0] = in[0] >> 2; 96 out[1] = (uint8_t)(((in[0] & 0x03) << 4) | (in[1] >> 4)); 97 out[2] = (uint8_t)(((in[1] & 0x0f) << 2) | (in[2] >> 6)); 98 out[3] = in[2] & 0x3f; 99 } 100 101 static int 102 b64_encode(FILE *fout, FILE *fin, size_t wrap) 103 { 104 uint8_t in[3]; 105 uint8_t out[4]; 106 size_t ilen; 107 size_t pos = 0; 108 int e; 109 110 while ((ilen = getinput(fin, in)) > 2) { 111 encode(out, in); 112 if ((e = putoutput(fout, out, ilen, wrap, &pos)) != 0) 113 return e; 114 } 115 116 if (ilen != 0) { 117 encode(out, in); 118 if ((e = putoutput(fout, out, ilen, wrap, &pos)) != 0) 119 return e; 120 } 121 122 if (pos && wrap) { 123 if (fputc('\n', fout) == -1) 124 return errno; 125 } 126 return 0; 127 } 128 129 130 static int 131 b64_decode(FILE *fout, FILE *fin, bool ignore) 132 { 133 int state, c; 134 uint8_t b, out; 135 char *pos; 136 137 state = 0; 138 out = 0; 139 140 while ((c = getc(fin)) != -1) { 141 if (ignore && isspace(c)) 142 continue; 143 144 if (c == '=') 145 break; 146 147 pos = strchr(B64, c); 148 if (pos == NULL) 149 return EFTYPE; 150 151 b = (uint8_t)(pos - B64); 152 153 switch (state) { 154 case 0: 155 out = (uint8_t)(b << 2); 156 break; 157 case 1: 158 out |= b >> 4; 159 if (fputc(out, fout) == -1) 160 return errno; 161 out = (uint8_t)((b & 0xf) << 4); 162 break; 163 case 2: 164 out |= b >> 2; 165 if (fputc(out, fout) == -1) 166 return errno; 167 out = (uint8_t)((b & 0x3) << 6); 168 break; 169 case 3: 170 out |= b; 171 if (fputc(out, fout) == -1) 172 return errno; 173 out = 0; 174 break; 175 default: 176 abort(); 177 } 178 state = (state + 1) & 3; 179 } 180 181 if (c == '=') { 182 switch (state) { 183 case 0: 184 case 1: 185 return EFTYPE; 186 case 2: 187 while ((c = getc(fin)) != -1) { 188 if (ignore && isspace(c)) 189 continue; 190 break; 191 } 192 if (c != '=') 193 return EFTYPE; 194 /*FALLTHROUGH*/ 195 case 3: 196 while ((c = getc(fin)) != -1) { 197 if (ignore && isspace(c)) 198 continue; 199 break; 200 } 201 if (c != -1) 202 return EFTYPE; 203 return 0; 204 default: 205 abort(); 206 } 207 } 208 209 if (c != -1 || state != 0) 210 return EFTYPE; 211 212 return 0; 213 } 214 215 static __dead void 216 usage(void) 217 { 218 fprintf(stderr, "Usage: %s [-di] [-w <wrap>] [<file>]...\n", 219 getprogname()); 220 exit(EXIT_FAILURE); 221 } 222 223 static void 224 doit(FILE *fout, FILE *fin, bool decode, bool ignore, size_t wrap) 225 { 226 int e; 227 228 if (decode) 229 e = b64_decode(fout, fin, ignore); 230 else 231 e = b64_encode(fout, fin, wrap); 232 233 if (e == 0) 234 return; 235 errc(EXIT_FAILURE, e, "%scoding failed", decode ? "De": "En"); 236 } 237 238 int 239 main(int argc, char *argv[]) 240 { 241 bool decode = false; 242 size_t wrap = 76; 243 bool ignore = false; 244 int c; 245 246 while ((c = getopt(argc, argv, "b:Ddiw:")) != -1) { 247 switch (c) { 248 case 'D': 249 decode = ignore = true; 250 break; 251 case 'd': 252 decode = true; 253 break; 254 case 'i': 255 ignore = true; 256 break; 257 case 'b': 258 case 'w': 259 wrap = (size_t)atoi(optarg); 260 break; 261 default: 262 usage(); 263 } 264 } 265 266 if (optind == argc) { 267 doit(stdout, stdin, decode, ignore, wrap); 268 return EXIT_SUCCESS; 269 } 270 271 for (c = optind; c < argc; c++) { 272 FILE *fp = strcmp(argv[c], "-") == 0 ? 273 stdin : fopen(argv[c], "r"); 274 if (fp == NULL) 275 err(EXIT_FAILURE, "Can't open `%s'", argv[c]); 276 doit(stdout, fp, decode, ignore, wrap); 277 if (fp != stdin) 278 fclose(fp); 279 fclose(fp); 280 } 281 282 return EXIT_SUCCESS; 283 } 284