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 /*
36 * look -- find lines in a sorted list.
37 *
38 * The man page said that TABs and SPACEs participate in -d comparisons.
39 * In fact, they were ignored. This implements historic practice, not
40 * the manual page.
41 */
42
43 #include <sys/types.h>
44 #include <sys/mman.h>
45 #include <sys/stat.h>
46
47 #include <err.h>
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <getopt.h>
51 #include <limits.h>
52 #include <locale.h>
53 #include <stdint.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58 #include <wchar.h>
59 #include <wctype.h>
60
61 #include "pathnames.h"
62
63 static char _path_words[] = _PATH_WORDS;
64
65 #define EQUAL 0
66 #define GREATER 1
67 #define LESS (-1)
68
69 static int dflag, fflag;
70
71 static char *binary_search(wchar_t *, unsigned char *, unsigned char *);
72 static int compare(wchar_t *, unsigned char *, unsigned char *);
73 static char *linear_search(wchar_t *, unsigned char *, unsigned char *);
74 static int look(wchar_t *, unsigned char *, unsigned char *);
75 static wchar_t *prepkey(const char *, wchar_t);
76 static void print_from(wchar_t *, unsigned char *, unsigned char *);
77
78 static void usage(void) __dead2;
79
80 static struct option longopts[] = {
81 { "alternative",no_argument, NULL, 'a' },
82 { "alphanum", no_argument, NULL, 'd' },
83 { "ignore-case",no_argument, NULL, 'i' },
84 { "terminate", required_argument, NULL, 't'},
85 { NULL, 0, NULL, 0 },
86 };
87
88 int
main(int argc,char * argv[])89 main(int argc, char *argv[])
90 {
91 struct stat sb;
92 int ch, fd, match;
93 wchar_t termchar;
94 unsigned char *back, *front;
95 unsigned const char *file;
96 wchar_t *key;
97
98 (void) setlocale(LC_CTYPE, "");
99
100 file = _path_words;
101 termchar = L'\0';
102 while ((ch = getopt_long(argc, argv, "+adft:", longopts, NULL)) != -1)
103 switch(ch) {
104 case 'a':
105 /* COMPATIBILITY */
106 break;
107 case 'd':
108 dflag = 1;
109 break;
110 case 'f':
111 fflag = 1;
112 break;
113 case 't':
114 if (mbrtowc(&termchar, optarg, MB_LEN_MAX, NULL) !=
115 strlen(optarg))
116 errx(2, "invalid termination character");
117 break;
118 case '?':
119 default:
120 usage();
121 }
122 argc -= optind;
123 argv += optind;
124
125 if (argc == 0)
126 usage();
127 if (argc == 1) /* But set -df by default. */
128 dflag = fflag = 1;
129 key = prepkey(*argv++, termchar);
130 if (argc >= 2)
131 file = *argv++;
132
133 match = 1;
134
135 do {
136 if ((fd = open(file, O_RDONLY, 0)) < 0 || fstat(fd, &sb))
137 err(2, "%s", file);
138 if ((uintmax_t)sb.st_size > (uintmax_t)SIZE_T_MAX)
139 errx(2, "%s: %s", file, strerror(EFBIG));
140 if (sb.st_size == 0) {
141 close(fd);
142 continue;
143 }
144 if ((front = mmap(NULL, (size_t)sb.st_size, PROT_READ, MAP_SHARED, fd, (off_t)0)) == MAP_FAILED)
145 err(2, "%s", file);
146 back = front + sb.st_size;
147 match *= (look(key, front, back));
148 close(fd);
149 } while (argc-- > 2 && (file = *argv++));
150
151 exit(match);
152 }
153
154 static wchar_t *
prepkey(const char * string,wchar_t termchar)155 prepkey(const char *string, wchar_t termchar)
156 {
157 const char *readp;
158 wchar_t *key, *writep;
159 wchar_t ch;
160 size_t clen;
161
162 /*
163 * Reformat search string and convert to wide character representation
164 * to avoid doing it multiple times later.
165 */
166 if ((key = malloc(sizeof(wchar_t) * (strlen(string) + 1))) == NULL)
167 err(2, NULL);
168 readp = string;
169 writep = key;
170 while ((clen = mbrtowc(&ch, readp, MB_LEN_MAX, NULL)) != 0) {
171 if (clen == (size_t)-1 || clen == (size_t)-2)
172 errc(2, EILSEQ, NULL);
173 if (fflag)
174 ch = towlower(ch);
175 if (!dflag || iswalnum(ch))
176 *writep++ = ch;
177 readp += clen;
178 }
179 *writep = L'\0';
180 if (termchar != L'\0' && (writep = wcschr(key, termchar)) != NULL)
181 *++writep = L'\0';
182 return (key);
183 }
184
185 static int
look(wchar_t * string,unsigned char * front,unsigned char * back)186 look(wchar_t *string, unsigned char *front, unsigned char *back)
187 {
188
189 front = binary_search(string, front, back);
190 front = linear_search(string, front, back);
191
192 if (front)
193 print_from(string, front, back);
194 return (front ? 0 : 1);
195 }
196
197
198 /*
199 * Binary search for "string" in memory between "front" and "back".
200 *
201 * This routine is expected to return a pointer to the start of a line at
202 * *or before* the first word matching "string". Relaxing the constraint
203 * this way simplifies the algorithm.
204 *
205 * Invariants:
206 * front points to the beginning of a line at or before the first
207 * matching string.
208 *
209 * back points to the beginning of a line at or after the first
210 * matching line.
211 *
212 * Base of the Invariants.
213 * front = NULL;
214 * back = EOF;
215 *
216 * Advancing the Invariants:
217 *
218 * p = first newline after halfway point from front to back.
219 *
220 * If the string at "p" is not greater than the string to match,
221 * p is the new front. Otherwise it is the new back.
222 *
223 * Termination:
224 *
225 * The definition of the routine allows it return at any point,
226 * since front is always at or before the line to print.
227 *
228 * In fact, it returns when the chosen "p" equals "back". This
229 * implies that there exists a string is least half as long as
230 * (back - front), which in turn implies that a linear search will
231 * be no more expensive than the cost of simply printing a string or two.
232 *
233 * Trying to continue with binary search at this point would be
234 * more trouble than it's worth.
235 */
236 #define SKIP_PAST_NEWLINE(p, back) \
237 while (p < back && *p++ != '\n');
238
239 static char *
binary_search(wchar_t * string,unsigned char * front,unsigned char * back)240 binary_search(wchar_t *string, unsigned char *front, unsigned char *back)
241 {
242 unsigned char *p;
243
244 p = front + (back - front) / 2;
245 SKIP_PAST_NEWLINE(p, back);
246
247 /*
248 * If the file changes underneath us, make sure we don't
249 * infinitely loop.
250 */
251 while (p < back && back > front) {
252 if (compare(string, p, back) == GREATER)
253 front = p;
254 else
255 back = p;
256 p = front + (back - front) / 2;
257 SKIP_PAST_NEWLINE(p, back);
258 }
259 return (front);
260 }
261
262 /*
263 * Find the first line that starts with string, linearly searching from front
264 * to back.
265 *
266 * Return NULL for no such line.
267 *
268 * This routine assumes:
269 *
270 * o front points at the first character in a line.
271 * o front is before or at the first line to be printed.
272 */
273 static char *
linear_search(wchar_t * string,unsigned char * front,unsigned char * back)274 linear_search(wchar_t *string, unsigned char *front, unsigned char *back)
275 {
276 while (front < back) {
277 switch (compare(string, front, back)) {
278 case EQUAL: /* Found it. */
279 return (front);
280 case LESS: /* No such string. */
281 return (NULL);
282 case GREATER: /* Keep going. */
283 break;
284 }
285 SKIP_PAST_NEWLINE(front, back);
286 }
287 return (NULL);
288 }
289
290 /*
291 * Print as many lines as match string, starting at front.
292 */
293 static void
print_from(wchar_t * string,unsigned char * front,unsigned char * back)294 print_from(wchar_t *string, unsigned char *front, unsigned char *back)
295 {
296 for (; front < back && compare(string, front, back) == EQUAL; ++front) {
297 for (; front < back && *front != '\n'; ++front)
298 if (putchar(*front) == EOF)
299 err(2, "stdout");
300 if (putchar('\n') == EOF)
301 err(2, "stdout");
302 }
303 }
304
305 /*
306 * Return LESS, GREATER, or EQUAL depending on how the string1 compares with
307 * string2 (s1 ??? s2).
308 *
309 * o Matches up to len(s1) are EQUAL.
310 * o Matches up to len(s2) are GREATER.
311 *
312 * Compare understands about the -f and -d flags, and treats comparisons
313 * appropriately.
314 *
315 * The string "s1" is null terminated. The string s2 is '\n' terminated (or
316 * "back" terminated).
317 */
318 static int
compare(wchar_t * s1,unsigned char * s2,unsigned char * back)319 compare(wchar_t *s1, unsigned char *s2, unsigned char *back)
320 {
321 wchar_t ch1, ch2;
322 size_t len2;
323
324 for (; *s1 && s2 < back && *s2 != '\n'; ++s1, s2 += len2) {
325 ch1 = *s1;
326 len2 = mbrtowc(&ch2, s2, back - s2, NULL);
327 if (len2 == (size_t)-1 || len2 == (size_t)-2) {
328 ch2 = *s2;
329 len2 = 1;
330 }
331 if (fflag)
332 ch2 = towlower(ch2);
333 if (dflag && !iswalnum(ch2)) {
334 /* Ignore character in comparison. */
335 --s1;
336 continue;
337 }
338 if (ch1 != ch2)
339 return (ch1 < ch2 ? LESS : GREATER);
340 }
341 return (*s1 ? GREATER : EQUAL);
342 }
343
344 static void
usage(void)345 usage(void)
346 {
347 (void)fprintf(stderr, "usage: look [-df] [-t char] string [file ...]\n");
348 exit(2);
349 }
350