1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * David Hitz of Auspex Systems, Inc. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#) Copyright (c) 1991, 1993 The Regents of the University of California. All rights reserved. 33 * @(#)look.c 8.2 (Berkeley) 5/4/95 34 * $FreeBSD: head/usr.bin/look/look.c 268242 2014-07-04 04:47:29Z eadler $ 35 */ 36 37 /* 38 * look -- find lines in a sorted list. 39 * 40 * The man page said that TABs and SPACEs participate in -d comparisons. 41 * In fact, they were ignored. This implements historic practice, not 42 * the manual page. 43 */ 44 45 #include <sys/types.h> 46 #include <sys/mman.h> 47 #include <sys/stat.h> 48 49 #include <err.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <getopt.h> 53 #include <limits.h> 54 #include <locale.h> 55 #include <stdint.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 #include <wchar.h> 61 #include <wctype.h> 62 63 #include "pathnames.h" 64 65 static char _path_words[] = _PATH_WORDS; 66 67 #define EQUAL 0 68 #define GREATER 1 69 #define LESS (-1) 70 71 static int dflag, fflag; 72 73 static char *binary_search(wchar_t *, unsigned char *, unsigned char *); 74 static int compare(wchar_t *, unsigned char *, unsigned char *); 75 static char *linear_search(wchar_t *, unsigned char *, unsigned char *); 76 static int look(wchar_t *, unsigned char *, unsigned char *); 77 static wchar_t *prepkey(const char *, wchar_t); 78 static void print_from(wchar_t *, unsigned char *, unsigned char *); 79 80 static void usage(void); 81 82 static struct option longopts[] = { 83 { "alternative",no_argument, NULL, 'a' }, 84 { "alphanum", no_argument, NULL, 'd' }, 85 { "ignore-case",no_argument, NULL, 'i' }, 86 { "terminate", required_argument, NULL, 't'}, 87 { NULL, 0, NULL, 0 }, 88 }; 89 90 int 91 main(int argc, char *argv[]) 92 { 93 struct stat sb; 94 int ch, fd, match; 95 wchar_t termchar; 96 unsigned char *back, *front; 97 unsigned const char *file; 98 wchar_t *key; 99 100 setlocale(LC_CTYPE, ""); 101 102 file = _path_words; 103 termchar = L'\0'; 104 while ((ch = getopt_long(argc, argv, "+adft:", longopts, NULL)) != -1) 105 switch(ch) { 106 case 'a': 107 /* COMPATIBILITY */ 108 break; 109 case 'd': 110 dflag = 1; 111 break; 112 case 'f': 113 fflag = 1; 114 break; 115 case 't': 116 if (mbrtowc(&termchar, optarg, MB_LEN_MAX, NULL) != 117 strlen(optarg)) 118 errx(2, "invalid termination character"); 119 break; 120 case '?': 121 default: 122 usage(); 123 } 124 argc -= optind; 125 argv += optind; 126 127 if (argc == 0) 128 usage(); 129 if (argc == 1) /* But set -df by default. */ 130 dflag = fflag = 1; 131 key = prepkey(*argv++, termchar); 132 if (argc >= 2) 133 file = *argv++; 134 135 match = 1; 136 137 do { 138 if ((fd = open(file, O_RDONLY, 0)) < 0 || fstat(fd, &sb)) 139 err(2, "%s", file); 140 if ((uintmax_t)sb.st_size > (uintmax_t)SIZE_T_MAX) 141 errx(2, "%s: %s", file, strerror(EFBIG)); 142 if (sb.st_size == 0) { 143 close(fd); 144 continue; 145 } 146 if ((front = mmap(NULL, (size_t)sb.st_size, PROT_READ, MAP_SHARED, fd, (off_t)0)) == MAP_FAILED) 147 err(2, "%s", file); 148 back = front + sb.st_size; 149 match *= (look(key, front, back)); 150 close(fd); 151 } while (argc-- > 2 && (file = *argv++)); 152 153 exit(match); 154 } 155 156 static wchar_t * 157 prepkey(const char *string, wchar_t termchar) 158 { 159 const char *readp; 160 wchar_t *key, *writep; 161 wchar_t ch; 162 size_t clen; 163 164 /* 165 * Reformat search string and convert to wide character representation 166 * to avoid doing it multiple times later. 167 */ 168 if ((key = malloc(sizeof(wchar_t) * (strlen(string) + 1))) == NULL) 169 err(2, NULL); 170 readp = string; 171 writep = key; 172 while ((clen = mbrtowc(&ch, readp, MB_LEN_MAX, NULL)) != 0) { 173 if (clen == (size_t)-1 || clen == (size_t)-2) 174 errc(2, EILSEQ, NULL); 175 if (fflag) 176 ch = towlower(ch); 177 if (!dflag || iswalnum(ch)) 178 *writep++ = ch; 179 readp += clen; 180 } 181 *writep = L'\0'; 182 if (termchar != L'\0' && (writep = wcschr(key, termchar)) != NULL) 183 *++writep = L'\0'; 184 return (key); 185 } 186 187 static int 188 look(wchar_t *string, unsigned char *front, unsigned char *back) 189 { 190 front = binary_search(string, front, back); 191 front = linear_search(string, front, back); 192 193 if (front) 194 print_from(string, front, back); 195 return (front ? 0 : 1); 196 } 197 198 199 /* 200 * Binary search for "string" in memory between "front" and "back". 201 * 202 * This routine is expected to return a pointer to the start of a line at 203 * *or before* the first word matching "string". Relaxing the constraint 204 * this way simplifies the algorithm. 205 * 206 * Invariants: 207 * front points to the beginning of a line at or before the first 208 * matching string. 209 * 210 * back points to the beginning of a line at or after the first 211 * matching line. 212 * 213 * Base of the Invariants. 214 * front = NULL; 215 * back = EOF; 216 * 217 * Advancing the Invariants: 218 * 219 * p = first newline after halfway point from front to back. 220 * 221 * If the string at "p" is not greater than the string to match, 222 * p is the new front. Otherwise it is the new back. 223 * 224 * Termination: 225 * 226 * The definition of the routine allows it return at any point, 227 * since front is always at or before the line to print. 228 * 229 * In fact, it returns when the chosen "p" equals "back". This 230 * implies that there exists a string is least half as long as 231 * (back - front), which in turn implies that a linear search will 232 * be no more expensive than the cost of simply printing a string or two. 233 * 234 * Trying to continue with binary search at this point would be 235 * more trouble than it's worth. 236 */ 237 #define SKIP_PAST_NEWLINE(p, back) \ 238 while (p < back && *p++ != '\n'); 239 240 static char * 241 binary_search(wchar_t *string, unsigned char *front, unsigned char *back) 242 { 243 unsigned char *p; 244 245 p = front + (back - front) / 2; 246 SKIP_PAST_NEWLINE(p, back); 247 248 /* 249 * If the file changes underneath us, make sure we don't 250 * infinitely loop. 251 */ 252 while (p < back && back > front) { 253 if (compare(string, p, back) == GREATER) 254 front = p; 255 else 256 back = p; 257 p = front + (back - front) / 2; 258 SKIP_PAST_NEWLINE(p, back); 259 } 260 return (front); 261 } 262 263 /* 264 * Find the first line that starts with string, linearly searching from front 265 * to back. 266 * 267 * Return NULL for no such line. 268 * 269 * This routine assumes: 270 * 271 * o front points at the first character in a line. 272 * o front is before or at the first line to be printed. 273 */ 274 static char * 275 linear_search(wchar_t *string, unsigned char *front, unsigned char *back) 276 { 277 while (front < back) { 278 switch (compare(string, front, back)) { 279 case EQUAL: /* Found it. */ 280 return (front); 281 case LESS: /* No such string. */ 282 return (NULL); 283 case GREATER: /* Keep going. */ 284 break; 285 } 286 SKIP_PAST_NEWLINE(front, back); 287 } 288 return (NULL); 289 } 290 291 /* 292 * Print as many lines as match string, starting at front. 293 */ 294 static void 295 print_from(wchar_t *string, unsigned char *front, unsigned char *back) 296 { 297 for (; front < back && compare(string, front, back) == EQUAL; ++front) { 298 for (; front < back && *front != '\n'; ++front) 299 if (putchar(*front) == EOF) 300 err(2, "stdout"); 301 if (putchar('\n') == EOF) 302 err(2, "stdout"); 303 } 304 } 305 306 /* 307 * Return LESS, GREATER, or EQUAL depending on how the string1 compares with 308 * string2 (s1 ??? s2). 309 * 310 * o Matches up to len(s1) are EQUAL. 311 * o Matches up to len(s2) are GREATER. 312 * 313 * Compare understands about the -f and -d flags, and treats comparisons 314 * appropriately. 315 * 316 * The string "s1" is null terminated. The string s2 is '\n' terminated (or 317 * "back" terminated). 318 */ 319 static int 320 compare(wchar_t *s1, unsigned char *s2, unsigned char *back) 321 { 322 wchar_t ch1, ch2; 323 size_t len2; 324 325 for (; *s1 && s2 < back && *s2 != '\n'; ++s1, s2 += len2) { 326 ch1 = *s1; 327 len2 = mbrtowc(&ch2, s2, back - s2, NULL); 328 if (len2 == (size_t)-1 || len2 == (size_t)-2) { 329 ch2 = *s2; 330 len2 = 1; 331 } 332 if (fflag) 333 ch2 = towlower(ch2); 334 if (dflag && !iswalnum(ch2)) { 335 /* Ignore character in comparison. */ 336 --s1; 337 continue; 338 } 339 if (ch1 != ch2) 340 return (ch1 < ch2 ? LESS : GREATER); 341 } 342 return (*s1 ? GREATER : EQUAL); 343 } 344 345 static void 346 usage(void) 347 { 348 fprintf(stderr, "usage: look [-df] [-t char] string [file ...]\n"); 349 exit(2); 350 } 351