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
main(int argc,char * argv[])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 *
prepkey(const char * string,wchar_t termchar)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
look(wchar_t * string,unsigned char * front,unsigned char * back)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 *
binary_search(wchar_t * string,unsigned char * front,unsigned char * back)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 *
linear_search(wchar_t * string,unsigned char * front,unsigned char * back)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
print_from(wchar_t * string,unsigned char * front,unsigned char * back)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
compare(wchar_t * s1,unsigned char * s2,unsigned char * back)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
usage(void)359 usage(void)
360 {
361 (void)fprintf(stderr, "usage: look [-df] [-t char] string [file ...]\n");
362 exit(2);
363 }
364