1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * David Hitz of Auspex Systems, Inc. 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 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #ifndef lint 36 static const char copyright[] = 37 "@(#) Copyright (c) 1991, 1993\n\ 38 The Regents of the University of California. All rights reserved.\n"; 39 #endif /* not lint */ 40 41 #ifndef lint 42 #if 0 43 static char sccsid[] = "@(#)look.c 8.2 (Berkeley) 5/4/95"; 44 #endif 45 #endif /* not lint */ 46 #include <sys/cdefs.h> 47 __FBSDID("$FreeBSD$"); 48 49 /* 50 * look -- find lines in a sorted list. 51 * 52 * The man page said that TABs and SPACEs participate in -d comparisons. 53 * In fact, they were ignored. This implements historic practice, not 54 * the manual page. 55 */ 56 57 #include <sys/types.h> 58 #include <sys/mman.h> 59 #include <sys/stat.h> 60 61 #include <err.h> 62 #include <errno.h> 63 #include <fcntl.h> 64 #include <getopt.h> 65 #include <limits.h> 66 #include <locale.h> 67 #include <stdint.h> 68 #include <stdio.h> 69 #include <stdlib.h> 70 #include <string.h> 71 #include <unistd.h> 72 #include <wchar.h> 73 #include <wctype.h> 74 75 #include "pathnames.h" 76 77 static char _path_words[] = _PATH_WORDS; 78 79 #define EQUAL 0 80 #define GREATER 1 81 #define LESS (-1) 82 83 static int dflag, fflag; 84 85 static char *binary_search(wchar_t *, unsigned char *, unsigned char *); 86 static int compare(wchar_t *, unsigned char *, unsigned char *); 87 static char *linear_search(wchar_t *, unsigned char *, unsigned char *); 88 static int look(wchar_t *, unsigned char *, unsigned char *); 89 static wchar_t *prepkey(const char *, wchar_t); 90 static void print_from(wchar_t *, unsigned char *, unsigned char *); 91 92 static void usage(void); 93 94 static struct option longopts[] = { 95 { "alternative",no_argument, NULL, 'a' }, 96 { "alphanum", no_argument, NULL, 'd' }, 97 { "ignore-case",no_argument, NULL, 'i' }, 98 { "terminate", required_argument, NULL, 't'}, 99 { NULL, 0, NULL, 0 }, 100 }; 101 102 int 103 main(int argc, char *argv[]) 104 { 105 struct stat sb; 106 int ch, fd, match; 107 wchar_t termchar; 108 unsigned char *back, *front; 109 unsigned const char *file; 110 wchar_t *key; 111 112 (void) setlocale(LC_CTYPE, ""); 113 114 file = _path_words; 115 termchar = L'\0'; 116 while ((ch = getopt_long(argc, argv, "+adft:", longopts, NULL)) != -1) 117 switch(ch) { 118 case 'a': 119 /* COMPATIBILITY */ 120 break; 121 case 'd': 122 dflag = 1; 123 break; 124 case 'f': 125 fflag = 1; 126 break; 127 case 't': 128 if (mbrtowc(&termchar, optarg, MB_LEN_MAX, NULL) != 129 strlen(optarg)) 130 errx(2, "invalid termination character"); 131 break; 132 case '?': 133 default: 134 usage(); 135 } 136 argc -= optind; 137 argv += optind; 138 139 if (argc == 0) 140 usage(); 141 if (argc == 1) /* But set -df by default. */ 142 dflag = fflag = 1; 143 key = prepkey(*argv++, termchar); 144 if (argc >= 2) 145 file = *argv++; 146 147 match = 1; 148 149 do { 150 if ((fd = open(file, O_RDONLY, 0)) < 0 || fstat(fd, &sb)) 151 err(2, "%s", file); 152 if ((uintmax_t)sb.st_size > (uintmax_t)SIZE_T_MAX) 153 errx(2, "%s: %s", file, strerror(EFBIG)); 154 if (sb.st_size == 0) { 155 close(fd); 156 continue; 157 } 158 if ((front = mmap(NULL, (size_t)sb.st_size, PROT_READ, MAP_SHARED, fd, (off_t)0)) == MAP_FAILED) 159 err(2, "%s", file); 160 back = front + sb.st_size; 161 match *= (look(key, front, back)); 162 close(fd); 163 } while (argc-- > 2 && (file = *argv++)); 164 165 exit(match); 166 } 167 168 static wchar_t * 169 prepkey(const char *string, wchar_t termchar) 170 { 171 const char *readp; 172 wchar_t *key, *writep; 173 wchar_t ch; 174 size_t clen; 175 176 /* 177 * Reformat search string and convert to wide character representation 178 * to avoid doing it multiple times later. 179 */ 180 if ((key = malloc(sizeof(wchar_t) * (strlen(string) + 1))) == NULL) 181 err(2, NULL); 182 readp = string; 183 writep = key; 184 while ((clen = mbrtowc(&ch, readp, MB_LEN_MAX, NULL)) != 0) { 185 if (clen == (size_t)-1 || clen == (size_t)-2) 186 errc(2, EILSEQ, NULL); 187 if (fflag) 188 ch = towlower(ch); 189 if (!dflag || iswalnum(ch)) 190 *writep++ = ch; 191 readp += clen; 192 } 193 *writep = L'\0'; 194 if (termchar != L'\0' && (writep = wcschr(key, termchar)) != NULL) 195 *++writep = L'\0'; 196 return (key); 197 } 198 199 static int 200 look(wchar_t *string, unsigned char *front, unsigned char *back) 201 { 202 203 front = binary_search(string, front, back); 204 front = linear_search(string, front, back); 205 206 if (front) 207 print_from(string, front, back); 208 return (front ? 0 : 1); 209 } 210 211 212 /* 213 * Binary search for "string" in memory between "front" and "back". 214 * 215 * This routine is expected to return a pointer to the start of a line at 216 * *or before* the first word matching "string". Relaxing the constraint 217 * this way simplifies the algorithm. 218 * 219 * Invariants: 220 * front points to the beginning of a line at or before the first 221 * matching string. 222 * 223 * back points to the beginning of a line at or after the first 224 * matching line. 225 * 226 * Base of the Invariants. 227 * front = NULL; 228 * back = EOF; 229 * 230 * Advancing the Invariants: 231 * 232 * p = first newline after halfway point from front to back. 233 * 234 * If the string at "p" is not greater than the string to match, 235 * p is the new front. Otherwise it is the new back. 236 * 237 * Termination: 238 * 239 * The definition of the routine allows it return at any point, 240 * since front is always at or before the line to print. 241 * 242 * In fact, it returns when the chosen "p" equals "back". This 243 * implies that there exists a string is least half as long as 244 * (back - front), which in turn implies that a linear search will 245 * be no more expensive than the cost of simply printing a string or two. 246 * 247 * Trying to continue with binary search at this point would be 248 * more trouble than it's worth. 249 */ 250 #define SKIP_PAST_NEWLINE(p, back) \ 251 while (p < back && *p++ != '\n'); 252 253 static char * 254 binary_search(wchar_t *string, unsigned char *front, unsigned char *back) 255 { 256 unsigned char *p; 257 258 p = front + (back - front) / 2; 259 SKIP_PAST_NEWLINE(p, back); 260 261 /* 262 * If the file changes underneath us, make sure we don't 263 * infinitely loop. 264 */ 265 while (p < back && back > front) { 266 if (compare(string, p, back) == GREATER) 267 front = p; 268 else 269 back = p; 270 p = front + (back - front) / 2; 271 SKIP_PAST_NEWLINE(p, back); 272 } 273 return (front); 274 } 275 276 /* 277 * Find the first line that starts with string, linearly searching from front 278 * to back. 279 * 280 * Return NULL for no such line. 281 * 282 * This routine assumes: 283 * 284 * o front points at the first character in a line. 285 * o front is before or at the first line to be printed. 286 */ 287 static char * 288 linear_search(wchar_t *string, unsigned char *front, unsigned char *back) 289 { 290 while (front < back) { 291 switch (compare(string, front, back)) { 292 case EQUAL: /* Found it. */ 293 return (front); 294 case LESS: /* No such string. */ 295 return (NULL); 296 case GREATER: /* Keep going. */ 297 break; 298 } 299 SKIP_PAST_NEWLINE(front, back); 300 } 301 return (NULL); 302 } 303 304 /* 305 * Print as many lines as match string, starting at front. 306 */ 307 static void 308 print_from(wchar_t *string, unsigned char *front, unsigned char *back) 309 { 310 for (; front < back && compare(string, front, back) == EQUAL; ++front) { 311 for (; front < back && *front != '\n'; ++front) 312 if (putchar(*front) == EOF) 313 err(2, "stdout"); 314 if (putchar('\n') == EOF) 315 err(2, "stdout"); 316 } 317 } 318 319 /* 320 * Return LESS, GREATER, or EQUAL depending on how the string1 compares with 321 * string2 (s1 ??? s2). 322 * 323 * o Matches up to len(s1) are EQUAL. 324 * o Matches up to len(s2) are GREATER. 325 * 326 * Compare understands about the -f and -d flags, and treats comparisons 327 * appropriately. 328 * 329 * The string "s1" is null terminated. The string s2 is '\n' terminated (or 330 * "back" terminated). 331 */ 332 static int 333 compare(wchar_t *s1, unsigned char *s2, unsigned char *back) 334 { 335 wchar_t ch1, ch2; 336 size_t len2; 337 338 for (; *s1 && s2 < back && *s2 != '\n'; ++s1, s2 += len2) { 339 ch1 = *s1; 340 len2 = mbrtowc(&ch2, s2, back - s2, NULL); 341 if (len2 == (size_t)-1 || len2 == (size_t)-2) { 342 ch2 = *s2; 343 len2 = 1; 344 } 345 if (fflag) 346 ch2 = towlower(ch2); 347 if (dflag && !iswalnum(ch2)) { 348 /* Ignore character in comparison. */ 349 --s1; 350 continue; 351 } 352 if (ch1 != ch2) 353 return (ch1 < ch2 ? LESS : GREATER); 354 } 355 return (*s1 ? GREATER : EQUAL); 356 } 357 358 static void 359 usage(void) 360 { 361 (void)fprintf(stderr, "usage: look [-df] [-t char] string [file ...]\n"); 362 exit(2); 363 } 364