xref: /netbsd-src/usr.sbin/makemandb/apropos-utils.c (revision 1580a27b92f58fcdcb23fdfbc04a7c2b54a0b7c8)
1 /*	$NetBSD: apropos-utils.c,v 1.39 2017/08/01 16:16:32 abhinav Exp $	*/
2 /*-
3  * Copyright (c) 2011 Abhinav Upadhyay <er.abhinav.upadhyay@gmail.com>
4  * All rights reserved.
5  *
6  * This code was developed as part of Google's Summer of Code 2011 program.
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  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in
16  *    the documentation and/or other materials provided with the
17  *    distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
22  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
23  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
25  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
27  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #include <sys/cdefs.h>
34 __RCSID("$NetBSD: apropos-utils.c,v 1.39 2017/08/01 16:16:32 abhinav Exp $");
35 
36 #include <sys/queue.h>
37 #include <sys/stat.h>
38 
39 #include <assert.h>
40 #include <ctype.h>
41 #include <err.h>
42 #include <math.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <util.h>
47 #include <zlib.h>
48 #include <term.h>
49 #include <unistd.h>
50 #undef tab	// XXX: manconf.h
51 
52 #include "apropos-utils.h"
53 #include "custom_apropos_tokenizer.h"
54 #include "manconf.h"
55 #include "fts3_tokenizer.h"
56 
57 typedef struct orig_callback_data {
58 	void *data;
59 	int (*callback) (void *, const char *, const char *, const char *,
60 		const char *, size_t);
61 } orig_callback_data;
62 
63 typedef struct inverse_document_frequency {
64 	double value;
65 	int status;
66 } inverse_document_frequency;
67 
68 /* weights for individual columns */
69 static const double col_weights[] = {
70 	2.0,	// NAME
71 	2.00,	// Name-description
72 	0.55,	// DESCRIPTION
73 	0.10,	// LIBRARY
74 	0.001,	//RETURN VALUES
75 	0.20,	//ENVIRONMENT
76 	0.01,	//FILES
77 	0.001,	//EXIT STATUS
78 	2.00,	//DIAGNOSTICS
79 	0.05,	//ERRORS
80 	0.00,	//md5_hash
81 	1.00	//machine
82 };
83 
84 #ifndef APROPOS_DEBUG
85 static int
86 register_tokenizer(sqlite3 *db)
87 {
88 	int rc;
89 	sqlite3_stmt *stmt;
90 	const sqlite3_tokenizer_module *p;
91 	const char *name = "custom_apropos_tokenizer";
92 	get_custom_apropos_tokenizer(&p);
93 	const char *sql = "SELECT fts3_tokenizer(?, ?)";
94 
95 	sqlite3_db_config(db, SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, 1, 0);
96 	rc = sqlite3_prepare_v2(db, sql, -1, &stmt, 0);
97 	if (rc != SQLITE_OK)
98 		return rc;
99 
100 	sqlite3_bind_text(stmt, 1, name, -1, SQLITE_STATIC);
101 	sqlite3_bind_blob(stmt, 2, &p, sizeof(p), SQLITE_STATIC);
102 	sqlite3_step(stmt);
103 
104 	return sqlite3_finalize(stmt);
105 }
106 #endif
107 
108 /*
109  * lower --
110  *  Converts the string str to lower case
111  */
112 char *
113 lower(char *str)
114 {
115 	assert(str);
116 	int i = 0;
117 	char c;
118 	while ((c = str[i]) != '\0')
119 		str[i++] = tolower((unsigned char) c);
120 	return str;
121 }
122 
123 /*
124 * concat--
125 *  Utility function. Concatenates together: dst, a space character and src.
126 * dst + " " + src
127 */
128 void
129 concat(char **dst, const char *src)
130 {
131 	concat2(dst, src, strlen(src));
132 }
133 
134 void
135 concat2(char **dst, const char *src, size_t srclen)
136 {
137 	size_t totallen, dstlen;
138 	char *mydst = *dst;
139 	assert(src != NULL);
140 
141 	/*
142 	 * If destination buffer dst is NULL, then simply
143 	 * strdup the source buffer
144 	 */
145 	if (mydst == NULL) {
146 		mydst = estrndup(src, srclen);
147 		*dst = mydst;
148 		return;
149 	}
150 
151 	dstlen = strlen(mydst);
152 	/*
153 	 * NUL Byte and separator space
154 	 */
155 	totallen = dstlen + srclen + 2;
156 
157 	mydst = erealloc(mydst, totallen);
158 
159 	/* Append a space at the end of dst */
160 	mydst[dstlen++] = ' ';
161 
162 	/* Now, copy src at the end of dst */
163 	memcpy(mydst + dstlen, src, srclen);
164 	mydst[dstlen + srclen] = '\0';
165 	*dst = mydst;
166 }
167 
168 void
169 close_db(sqlite3 *db)
170 {
171 	sqlite3_close(db);
172 	sqlite3_shutdown();
173 }
174 
175 /*
176  * create_db --
177  *  Creates the database schema.
178  */
179 static int
180 create_db(sqlite3 *db)
181 {
182 	const char *sqlstr = NULL;
183 	char *schemasql;
184 	char *errmsg = NULL;
185 
186 /*------------------------ Create the tables------------------------------*/
187 
188 #if NOTYET
189 	sqlite3_exec(db, "PRAGMA journal_mode = WAL", NULL, NULL, NULL);
190 #else
191 	sqlite3_exec(db, "PRAGMA journal_mode = DELETE", NULL, NULL, NULL);
192 #endif
193 
194 	schemasql = sqlite3_mprintf("PRAGMA user_version = %d",
195 	    APROPOS_SCHEMA_VERSION);
196 	sqlite3_exec(db, schemasql, NULL, NULL, &errmsg);
197 	if (errmsg != NULL)
198 		goto out;
199 	sqlite3_free(schemasql);
200 
201 	sqlstr =
202 	    //mandb
203 	    "CREATE VIRTUAL TABLE mandb USING fts4(section, name, "
204 		"name_desc, desc, lib, return_vals, env, files, "
205 		"exit_status, diagnostics, errors, md5_hash UNIQUE, machine, "
206 #ifndef APROPOS_DEBUG
207 		"compress=zip, uncompress=unzip, tokenize=custom_apropos_tokenizer, "
208 #else
209 		"tokenize=porter, "
210 #endif
211 		"notindexed=section, notindexed=md5_hash); "
212 	    //mandb_meta
213 	    "CREATE TABLE IF NOT EXISTS mandb_meta(device, inode, mtime, "
214 		"file UNIQUE, md5_hash UNIQUE, id  INTEGER PRIMARY KEY); "
215 	    //mandb_links
216 	    "CREATE TABLE IF NOT EXISTS mandb_links(link COLLATE NOCASE, target, section, "
217 		"machine, md5_hash); ";
218 
219 	sqlite3_exec(db, sqlstr, NULL, NULL, &errmsg);
220 	if (errmsg != NULL)
221 		goto out;
222 
223 	sqlstr =
224 	    "CREATE INDEX IF NOT EXISTS index_mandb_links ON mandb_links "
225 		"(link); "
226 	    "CREATE INDEX IF NOT EXISTS index_mandb_meta_dev ON mandb_meta "
227 		"(device, inode); "
228 	    "CREATE INDEX IF NOT EXISTS index_mandb_links_md5 ON mandb_links "
229 		"(md5_hash);";
230 	sqlite3_exec(db, sqlstr, NULL, NULL, &errmsg);
231 	if (errmsg != NULL)
232 		goto out;
233 	return 0;
234 
235 out:
236 	warnx("%s", errmsg);
237 	free(errmsg);
238 	sqlite3_close(db);
239 	sqlite3_shutdown();
240 	return -1;
241 }
242 
243 /*
244  * zip --
245  *  User defined Sqlite function to compress the FTS table
246  */
247 static void
248 zip(sqlite3_context *pctx, int nval, sqlite3_value **apval)
249 {
250 	int nin;
251 	long int nout;
252 	const unsigned char * inbuf;
253 	unsigned char *outbuf;
254 
255 	assert(nval == 1);
256 	nin = sqlite3_value_bytes(apval[0]);
257 	inbuf = (const unsigned char *) sqlite3_value_blob(apval[0]);
258 	nout = nin + 13 + (nin + 999) / 1000;
259 	outbuf = emalloc(nout);
260 	compress(outbuf, (unsigned long *) &nout, inbuf, nin);
261 	sqlite3_result_blob(pctx, outbuf, nout, free);
262 }
263 
264 /*
265  * unzip --
266  *  User defined Sqlite function to uncompress the FTS table.
267  */
268 static void
269 unzip(sqlite3_context *pctx, int nval, sqlite3_value **apval)
270 {
271 	unsigned int rc;
272 	unsigned char *outbuf;
273 	z_stream stream;
274 
275 	assert(nval == 1);
276 	stream.next_in = __UNCONST(sqlite3_value_blob(apval[0]));
277 	stream.avail_in = sqlite3_value_bytes(apval[0]);
278 	stream.avail_out = stream.avail_in * 2 + 100;
279 	stream.next_out = outbuf = emalloc(stream.avail_out);
280 	stream.zalloc = NULL;
281 	stream.zfree = NULL;
282 
283 	if (inflateInit(&stream) != Z_OK) {
284 		free(outbuf);
285 		return;
286 	}
287 
288 	while ((rc = inflate(&stream, Z_SYNC_FLUSH)) != Z_STREAM_END) {
289 		if (rc != Z_OK ||
290 		    (stream.avail_out != 0 && stream.avail_in == 0)) {
291 			free(outbuf);
292 			return;
293 		}
294 		outbuf = erealloc(outbuf, stream.total_out * 2);
295 		stream.next_out = outbuf + stream.total_out;
296 		stream.avail_out = stream.total_out;
297 	}
298 	if (inflateEnd(&stream) != Z_OK) {
299 		free(outbuf);
300 		return;
301 	}
302 	outbuf = erealloc(outbuf, stream.total_out);
303 	sqlite3_result_text(pctx, (const char *)outbuf, stream.total_out, free);
304 }
305 
306 /*
307  * get_dbpath --
308  *   Read the path of the database from man.conf and return.
309  */
310 char *
311 get_dbpath(const char *manconf)
312 {
313 	TAG *tp;
314 	char *dbpath;
315 
316 	config(manconf);
317 	tp = gettag("_mandb", 1);
318 	if (!tp)
319 		return NULL;
320 
321 	if (TAILQ_EMPTY(&tp->entrylist))
322 		return NULL;
323 
324 	dbpath = TAILQ_LAST(&tp->entrylist, tqh)->s;
325 	return dbpath;
326 }
327 
328 /* init_db --
329  *   Prepare the database. Register the compress/uncompress functions and the
330  *   stopword tokenizer.
331  *	 db_flag specifies the mode in which to open the database. 3 options are
332  *   available:
333  *   	1. DB_READONLY: Open in READONLY mode. An error if db does not exist.
334  *  	2. DB_READWRITE: Open in read-write mode. An error if db does not exist.
335  *  	3. DB_CREATE: Open in read-write mode. It will try to create the db if
336  *			it does not exist already.
337  *  RETURN VALUES:
338  *		The function will return NULL in case the db does not exist
339  *		and DB_CREATE
340  *  	was not specified. And in case DB_CREATE was specified and yet NULL is
341  *  	returned, then there was some other error.
342  *  	In normal cases the function should return a handle to the db.
343  */
344 sqlite3 *
345 init_db(mandb_access_mode db_flag, const char *manconf)
346 {
347 	sqlite3 *db = NULL;
348 	sqlite3_stmt *stmt;
349 	struct stat sb;
350 	int rc;
351 	int create_db_flag = 0;
352 
353 	char *dbpath = get_dbpath(manconf);
354 	if (dbpath == NULL)
355 		errx(EXIT_FAILURE, "_mandb entry not found in man.conf");
356 
357 	if (!(stat(dbpath, &sb) == 0 && S_ISREG(sb.st_mode))) {
358 		/* Database does not exist, check if DB_CREATE was specified,
359 		 * and set flag to create the database schema
360 		 */
361 		if (db_flag != (MANDB_CREATE)) {
362 			warnx("Missing apropos database. "
363 			      "Please run makemandb to create it.");
364 			return NULL;
365 		}
366 		create_db_flag = 1;
367 	} else {
368 		/*
369 		 * Database exists. Check if we have the permissions
370 		 * to read/write the files
371 		 */
372 		int access_mode = R_OK;
373 		switch (db_flag) {
374 		case MANDB_CREATE:
375 		case MANDB_WRITE:
376 			access_mode |= W_OK;
377 			break;
378 		default:
379 			break;
380 		}
381 		if ((access(dbpath, access_mode)) != 0) {
382 			warnx("Unable to access the database, please check"
383 			    " permissions for `%s'", dbpath);
384 			return NULL;
385 		}
386 	}
387 
388 	sqlite3_initialize();
389 	rc = sqlite3_open_v2(dbpath, &db, db_flag, NULL);
390 
391 	if (rc != SQLITE_OK) {
392 		warnx("%s", sqlite3_errmsg(db));
393 		goto error;
394 	}
395 
396 	sqlite3_extended_result_codes(db, 1);
397 
398 #ifndef APROPOS_DEBUG
399 	rc = register_tokenizer(db);
400 	if (rc != SQLITE_OK) {
401 		warnx("Unable to register custom tokenizer: %s", sqlite3_errmsg(db));
402 		goto error;
403 	}
404 #endif
405 
406 	if (create_db_flag && create_db(db) < 0) {
407 		warnx("%s", "Unable to create database schema");
408 		goto error;
409 	}
410 
411 	rc = sqlite3_prepare_v2(db, "PRAGMA user_version", -1, &stmt, NULL);
412 	if (rc != SQLITE_OK) {
413 		warnx("Unable to query schema version: %s",
414 		    sqlite3_errmsg(db));
415 		goto error;
416 	}
417 	if (sqlite3_step(stmt) != SQLITE_ROW) {
418 		sqlite3_finalize(stmt);
419 		warnx("Unable to query schema version: %s",
420 		    sqlite3_errmsg(db));
421 		goto error;
422 	}
423 	if (sqlite3_column_int(stmt, 0) != APROPOS_SCHEMA_VERSION) {
424 		sqlite3_finalize(stmt);
425 		warnx("Incorrect schema version found. "
426 		      "Please run makemandb -f.");
427 		goto error;
428 	}
429 	sqlite3_finalize(stmt);
430 
431 
432 	/* Register the zip and unzip functions for FTS compression */
433 	rc = sqlite3_create_function(db, "zip", 1, SQLITE_ANY, NULL, zip,
434 	    NULL, NULL);
435 	if (rc != SQLITE_OK) {
436 		warnx("Unable to register function: compress: %s",
437 		    sqlite3_errmsg(db));
438 		goto error;
439 	}
440 
441 	rc = sqlite3_create_function(db, "unzip", 1, SQLITE_ANY, NULL,
442                                  unzip, NULL, NULL);
443 	if (rc != SQLITE_OK) {
444 		warnx("Unable to register function: uncompress: %s",
445 		    sqlite3_errmsg(db));
446 		goto error;
447 	}
448 	return db;
449 
450 error:
451 	close_db(db);
452 	return NULL;
453 }
454 
455 /*
456  * rank_func --
457  *  Sqlite user defined function for ranking the documents.
458  *  For each phrase of the query, it computes the tf and idf and adds them over.
459  *  It computes the final rank, by multiplying tf and idf together.
460  *  Weight of term t for document d = (term frequency of t in d *
461  *                                      inverse document frequency of t)
462  *
463  *  Term Frequency of term t in document d = Number of times t occurs in d /
464  *	Number of times t appears in all documents
465  *
466  *  Inverse document frequency of t = log(Total number of documents /
467  *										Number of documents in which t occurs)
468  */
469 static void
470 rank_func(sqlite3_context *pctx, int nval, sqlite3_value **apval)
471 {
472 	inverse_document_frequency *idf = sqlite3_user_data(pctx);
473 	double tf = 0.0;
474 	const unsigned int *matchinfo;
475 	int ncol;
476 	int nphrase;
477 	int iphrase;
478 	int ndoc;
479 	int doclen = 0;
480 	const double k = 3.75;
481 	/*
482 	 * Check that the number of arguments passed to this
483 	 * function is correct.
484 	 */
485 	assert(nval == 1);
486 
487 	matchinfo = (const unsigned int *) sqlite3_value_blob(apval[0]);
488 	nphrase = matchinfo[0];
489 	ncol = matchinfo[1];
490 	ndoc = matchinfo[2 + 3 * ncol * nphrase + ncol];
491 	for (iphrase = 0; iphrase < nphrase; iphrase++) {
492 		int icol;
493 		const unsigned int *phraseinfo =
494 		    &matchinfo[2 + ncol + iphrase * ncol * 3];
495 		for(icol = 1; icol < ncol; icol++) {
496 
497 			/* nhitcount: number of times the current phrase occurs
498 			 * 	in the current column in the current document.
499 			 * nglobalhitcount: number of times current phrase
500 			 *	occurs in the current column in all documents.
501 			 * ndocshitcount: number of documents in which the
502 			 *	current phrase occurs in the current column at
503 			 *	least once.
504 			 */
505   			int nhitcount = phraseinfo[3 * icol];
506 			int nglobalhitcount = phraseinfo[3 * icol + 1];
507 			int ndocshitcount = phraseinfo[3 * icol + 2];
508 			doclen = matchinfo[2 + icol ];
509 			double weight = col_weights[icol - 1];
510 			if (idf->status == 0 && ndocshitcount)
511 				idf->value +=
512 				    log(((double)ndoc / ndocshitcount))* weight;
513 
514 			/*
515 			 * Dividing the tf by document length to normalize
516 			 * the effect of longer documents.
517 			 */
518 			if (nglobalhitcount > 0 && nhitcount)
519 				tf += (((double)nhitcount  * weight)
520 				    / (nglobalhitcount * doclen));
521 		}
522 	}
523 	idf->status = 1;
524 
525 	/*
526 	 * Final score: Dividing by k + tf further normalizes the weight
527 	 * leading to better results. The value of k is experimental
528 	 */
529 	double score = (tf * idf->value) / (k + tf);
530 	sqlite3_result_double(pctx, score);
531 	return;
532 }
533 
534 /*
535  * generates sql query for matching the user entered query
536  */
537 static char *
538 generate_search_query(query_args *args, const char *snippet_args[3])
539 {
540 	const char *default_snippet_args[3];
541 	char *section_clause = NULL;
542 	char *limit_clause = NULL;
543 	char *machine_clause = NULL;
544 	char *query = NULL;
545 
546 	if (args->machine) {
547 		machine_clause = sqlite3_mprintf("AND mandb.machine=%Q", args->machine);
548 		if (machine_clause == NULL)
549 			goto RETURN;
550 	}
551 
552 	if (args->nrec >= 0) {
553 		/* Use the provided number of records and offset */
554 		limit_clause = sqlite3_mprintf(" LIMIT %d OFFSET %d",
555 		    args->nrec, args->offset);
556 		if (limit_clause == NULL)
557 			goto RETURN;
558 	}
559 
560 	/* We want to build a query of the form: "select x,y,z from mandb where
561 	 * mandb match :query [AND (section IN ('1', '2')]
562 	 * ORDER BY rank DESC [LIMIT 10 OFFSET 0]"
563 	 * NOTES:
564 	 *   1. The portion in first pair of square brackets is optional.
565 	 *      It will be there only if the user has specified an option
566 	 *      to search in one or more specific sections.
567 	 *   2. The LIMIT portion will be there if the user has specified
568 	 *      a limit using the -n option.
569 	 */
570 	if (args->sections && args->sections[0]) {
571 		concat(&section_clause, " AND mandb.section IN (");
572 		for (size_t i = 0; args->sections[i]; i++) {
573 			char *temp;
574 			char c = args->sections[i + 1]? ',': ')';
575 			if ((temp = sqlite3_mprintf("%Q%c", args->sections[i], c)) == NULL)
576 				goto RETURN;
577 			concat(&section_clause, temp);
578 			free(temp);
579 		}
580 	}
581 
582 	if (snippet_args == NULL) {
583 		default_snippet_args[0] = "";
584 		default_snippet_args[1] = "";
585 		default_snippet_args[2] = "...";
586 		snippet_args = default_snippet_args;
587 	}
588 
589 	if (args->legacy) {
590 	    char *wild;
591 	    easprintf(&wild, "%%%s%%", args->search_str);
592 	    query = sqlite3_mprintf("SELECT section, name, name_desc, machine"
593 		" FROM mandb"
594 		" WHERE name LIKE %Q OR name_desc LIKE %Q "
595 		"%s"
596 		"%s",
597 		wild, wild,
598 		section_clause ? section_clause : "",
599 		limit_clause ? limit_clause : "");
600 		free(wild);
601 	} else if (strchr(args->search_str, ' ') == NULL) {
602 		/*
603 		 * If it's a single word query, we want to search in the
604 		 * links table as well. If the link table contains an entry
605 		 * for the queried keyword, we want to use that as the name of
606 		 * the man page.
607 		 * For example, for `apropos realloc` the output should be
608 		 * realloc(3) and not malloc(3).
609 		 */
610 		query = sqlite3_mprintf(
611 		    "SELECT section, name, name_desc, machine,"
612 		    " snippet(mandb, %Q, %Q, %Q, -1, 40 ),"
613 		    " rank_func(matchinfo(mandb, \"pclxn\")) AS rank"
614 		    " FROM mandb WHERE name NOT IN ("
615 		    " SELECT target FROM mandb_links WHERE link=%Q AND"
616 		    " mandb_links.section=mandb.section) AND mandb MATCH %Q %s %s"
617 		    " UNION"
618 		    " SELECT mandb.section, mandb_links.link AS name, mandb.name_desc,"
619 		    " mandb.machine, '' AS snippet, 100.00 AS rank"
620 		    " FROM mandb JOIN mandb_links ON mandb.name=mandb_links.target and"
621 		    " mandb.section=mandb_links.section WHERE mandb_links.link=%Q"
622 		    " %s %s"
623 		    " ORDER BY rank DESC %s",
624 		    snippet_args[0], snippet_args[1], snippet_args[2],
625 		    args->search_str, args->search_str, section_clause ? section_clause : "",
626 		    machine_clause ? machine_clause : "", args->search_str,
627 		    machine_clause ? machine_clause : "",
628 		    section_clause ? section_clause : "",
629 		    limit_clause ? limit_clause : "");
630 	} else {
631 	    query = sqlite3_mprintf("SELECT section, name, name_desc, machine,"
632 		" snippet(mandb, %Q, %Q, %Q, -1, 40 ),"
633 		" rank_func(matchinfo(mandb, \"pclxn\")) AS rank"
634 		" FROM mandb"
635 		" WHERE mandb MATCH %Q %s "
636 		"%s"
637 		" ORDER BY rank DESC"
638 		"%s",
639 		snippet_args[0], snippet_args[1], snippet_args[2],
640 		args->search_str, machine_clause ? machine_clause : "",
641 		section_clause ? section_clause : "",
642 		limit_clause ? limit_clause : "");
643 	}
644 
645 RETURN:
646 	free(machine_clause);
647 	free(section_clause);
648 	free(limit_clause);
649 	return query;
650 }
651 
652 /*
653  * Execute the full text search query and return the number of results
654  * obtained.
655  */
656 static unsigned int
657 execute_search_query(sqlite3 *db, char *query, query_args *args)
658 {
659 	sqlite3_stmt *stmt;
660 	const char *section;
661 	char *name;
662 	char *slash_ptr;
663 	const char *name_desc;
664 	const char *machine;
665 	const char *snippet = "";
666 	const char *name_temp;
667 	char *m = NULL;
668 	int rc;
669 	inverse_document_frequency idf = {0, 0};
670 
671 	if (!args->legacy) {
672 		/* Register the rank function */
673 		rc = sqlite3_create_function(db, "rank_func", 1, SQLITE_ANY,
674 		    (void *) &idf, rank_func, NULL, NULL);
675 		if (rc != SQLITE_OK) {
676 			warnx("Unable to register the ranking function: %s",
677 			    sqlite3_errmsg(db));
678 			sqlite3_close(db);
679 			sqlite3_shutdown();
680 			exit(EXIT_FAILURE);
681 		}
682 	}
683 
684 	rc = sqlite3_prepare_v2(db, query, -1, &stmt, NULL);
685 	if (rc == SQLITE_IOERR) {
686 		warnx("Corrupt database. Please rerun makemandb");
687 		return -1;
688 	} else if (rc != SQLITE_OK) {
689 		warnx("%s", sqlite3_errmsg(db));
690 		return -1;
691 	}
692 
693 	unsigned int nresults = 0;
694 	while (sqlite3_step(stmt) == SQLITE_ROW) {
695 		nresults++;
696 		section = (const char *) sqlite3_column_text(stmt, 0);
697 		name_temp = (const char *) sqlite3_column_text(stmt, 1);
698 		name_desc = (const char *) sqlite3_column_text(stmt, 2);
699 		machine = (const char *) sqlite3_column_text(stmt, 3);
700 		if (!args->legacy)
701 			snippet = (const char *) sqlite3_column_text(stmt, 4);
702 		if ((slash_ptr = strrchr(name_temp, '/')) != NULL)
703 			name_temp = slash_ptr + 1;
704 		if (machine && machine[0]) {
705 			m = estrdup(machine);
706 			easprintf(&name, "%s/%s", lower(m), name_temp);
707 			free(m);
708 		} else {
709 			name = estrdup((const char *)
710 			    sqlite3_column_text(stmt, 1));
711 		}
712 
713 		(args->callback)(args->callback_data, section, name,
714 		    name_desc, snippet, args->legacy? 0: strlen(snippet));
715 		free(name);
716 	}
717 	sqlite3_finalize(stmt);
718 	return nresults;
719 }
720 
721 
722 /*
723  *  run_query_internal --
724  *  Performs the searches for the keywords entered by the user.
725  *  The 2nd param: snippet_args is an array of strings providing values for the
726  *  last three parameters to the snippet function of sqlite. (Look at the docs).
727  *  The 3rd param: args contains rest of the search parameters. Look at
728  *  arpopos-utils.h for the description of individual fields.
729  *
730  */
731 static int
732 run_query_internal(sqlite3 *db, const char *snippet_args[3], query_args *args)
733 {
734 	char *query;
735 	query = generate_search_query(args, snippet_args);
736 	if (query == NULL) {
737 		*args->errmsg = estrdup("malloc failed");
738 		return -1;
739 	}
740 
741 	execute_search_query(db, query, args);
742 	sqlite3_free(query);
743 	return *(args->errmsg) == NULL ? 0 : -1;
744 }
745 
746 static char *
747 get_escaped_html_string(const char *src, size_t *slen)
748 {
749 	static const char trouble[] = "<>\"&\002\003";
750 	/*
751 	 * First scan the src to find out the number of occurrences
752 	 * of {'>', '<' '"', '&'}.  Then allocate a new buffer with
753 	 * sufficient space to be able to store the quoted versions
754 	 * of the special characters {&gt;, &lt;, &quot;, &amp;}.
755 	 * Copy over the characters from the original src into
756 	 * this buffer while replacing the special characters with
757 	 * their quoted versions.
758 	 */
759 	char *dst, *ddst;
760 	size_t count;
761 	const char *ssrc;
762 
763 	for (count = 0, ssrc = src; *src; count++) {
764 		size_t sz = strcspn(src, trouble);
765 		src += sz + 1;
766 	}
767 
768 
769 #define append(a)				\
770     do {					\
771 	memcpy(dst, (a), sizeof(a) - 1);	\
772 	dst += sizeof(a) - 1; 			\
773     } while (/*CONSTCOND*/0)
774 
775 
776 	ddst = dst = emalloc(*slen + count * 5 + 1);
777 	for (src = ssrc; *src; src++) {
778 		switch (*src) {
779 		case '<':
780 			append("&lt;");
781 			break;
782 		case '>':
783 			append("&gt;");
784 			break;
785 		case '\"':
786 			append("&quot;");
787 			break;
788 		case '&':
789 			/*
790 			 * Don't perform the quoting if this & is part of
791 			 * an mdoc escape sequence, e.g. \&
792 			 */
793 			if (src != ssrc && src[-1] != '\\')
794 				append("&amp;");
795 			else
796 				append("&");
797 			break;
798 		case '\002':
799 			append("<b>");
800 			break;
801 		case '\003':
802 			append("</b>");
803 			break;
804 		default:
805 			*dst++ = *src;
806 			break;
807 		}
808 	}
809 	*dst = '\0';
810 	*slen = dst - ddst;
811 	return ddst;
812 }
813 
814 
815 /*
816  * callback_html --
817  *  Callback function for run_query_html. It builds the html output and then
818  *  calls the actual user supplied callback function.
819  */
820 static int
821 callback_html(void *data, const char *section, const char *name,
822     const char *name_desc, const char *snippet, size_t snippet_length)
823 {
824 	struct orig_callback_data *orig_data = data;
825 	int (*callback)(void *, const char *, const char *, const char *,
826 	    const char *, size_t) = orig_data->callback;
827 	size_t length = snippet_length;
828 	size_t name_description_length = strlen(name_desc);
829 	char *qsnippet = get_escaped_html_string(snippet, &length);
830 	char *qname_description = get_escaped_html_string(name_desc,
831 	    &name_description_length);
832 
833 	(*callback)(orig_data->data, section, name, qname_description,
834 	    qsnippet, length);
835 	free(qsnippet);
836 	free(qname_description);
837 	return 0;
838 }
839 
840 /*
841  * run_query_html --
842  *  Utility function to output query result in HTML format.
843  *  It internally calls run_query only, but it first passes the output to its
844  *  own custom callback function, which preprocess the snippet for quoting
845  *  inline HTML fragments.
846  *  After that it delegates the call the actual user supplied callback function.
847  */
848 static int
849 run_query_html(sqlite3 *db, query_args *args)
850 {
851 	struct orig_callback_data orig_data;
852 	orig_data.callback = args->callback;
853 	orig_data.data = args->callback_data;
854 	const char *snippet_args[] = {"\002", "\003", "..."};
855 	args->callback = &callback_html;
856 	args->callback_data = (void *) &orig_data;
857 	return run_query_internal(db, snippet_args, args);
858 }
859 
860 /*
861  * underline a string, pager style.
862  */
863 static char *
864 ul_pager(int ul, const char *s)
865 {
866 	size_t len;
867 	char *dst, *d;
868 
869 	if (!ul)
870 		return estrdup(s);
871 
872 	// a -> _\ba
873 	len = strlen(s) * 3 + 1;
874 
875 	d = dst = emalloc(len);
876 	while (*s) {
877 		*d++ = '_';
878 		*d++ = '\b';
879 		*d++ = *s++;
880 	}
881 	*d = '\0';
882 	return dst;
883 }
884 
885 /*
886  * callback_pager --
887  *  A callback similar to callback_html. It overstrikes the matching text in
888  *  the snippet so that it appears emboldened when viewed using a pager like
889  *  more or less.
890  */
891 static int
892 callback_pager(void *data, const char *section, const char *name,
893 	const char *name_desc, const char *snippet, size_t snippet_length)
894 {
895 	struct orig_callback_data *orig_data = data;
896 	char *psnippet;
897 	const char *temp = snippet;
898 	int count = 0;
899 	int i = 0, did;
900 	size_t sz = 0;
901 	size_t psnippet_length;
902 
903 	/* Count the number of bytes of matching text. For each of these
904 	 * bytes we will use 2 extra bytes to overstrike it so that it
905 	 * appears bold when viewed using a pager.
906 	 */
907 	while (*temp) {
908 		sz = strcspn(temp, "\002\003");
909 		temp += sz;
910 		if (*temp == '\003') {
911 			count += 2 * (sz);
912 		}
913 		temp++;
914 	}
915 
916 	psnippet_length = snippet_length + count;
917 	psnippet = emalloc(psnippet_length + 1);
918 
919 	/* Copy the bytes from snippet to psnippet:
920 	 * 1. Copy the bytes before \002 as it is.
921 	 * 2. The bytes after \002 need to be overstriked till we
922 	 *    encounter \003.
923 	 * 3. To overstrike a byte 'A' we need to write 'A\bA'
924 	 */
925 	did = 0;
926 	while (*snippet) {
927 		sz = strcspn(snippet, "\002");
928 		memcpy(&psnippet[i], snippet, sz);
929 		snippet += sz;
930 		i += sz;
931 
932 		/* Don't change this. Advancing the pointer without reading the byte
933 		 * is causing strange behavior.
934 		 */
935 		if (*snippet == '\002')
936 			snippet++;
937 		while (*snippet && *snippet != '\003') {
938 			did = 1;
939 			psnippet[i++] = *snippet;
940 			psnippet[i++] = '\b';
941 			psnippet[i++] = *snippet++;
942 		}
943 		if (*snippet)
944 			snippet++;
945 	}
946 
947 	psnippet[i] = 0;
948 	char *ul_section = ul_pager(did, section);
949 	char *ul_name = ul_pager(did, name);
950 	char *ul_name_desc = ul_pager(did, name_desc);
951 	(orig_data->callback)(orig_data->data, ul_section, ul_name,
952 	    ul_name_desc, psnippet, psnippet_length);
953 	free(ul_section);
954 	free(ul_name);
955 	free(ul_name_desc);
956 	free(psnippet);
957 	return 0;
958 }
959 
960 struct term_args {
961 	struct orig_callback_data *orig_data;
962 	const char *smul;
963 	const char *rmul;
964 };
965 
966 /*
967  * underline a string, pager style.
968  */
969 static char *
970 ul_term(const char *s, const struct term_args *ta)
971 {
972 	char *dst;
973 
974 	easprintf(&dst, "%s%s%s", ta->smul, s, ta->rmul);
975 	return dst;
976 }
977 
978 /*
979  * callback_term --
980  *  A callback similar to callback_html. It overstrikes the matching text in
981  *  the snippet so that it appears emboldened when viewed using a pager like
982  *  more or less.
983  */
984 static int
985 callback_term(void *data, const char *section, const char *name,
986 	const char *name_desc, const char *snippet, size_t snippet_length)
987 {
988 	struct term_args *ta = data;
989 	struct orig_callback_data *orig_data = ta->orig_data;
990 
991 	char *ul_section = ul_term(section, ta);
992 	char *ul_name = ul_term(name, ta);
993 	char *ul_name_desc = ul_term(name_desc, ta);
994 	(orig_data->callback)(orig_data->data, ul_section, ul_name,
995 	    ul_name_desc, snippet, snippet_length);
996 	free(ul_section);
997 	free(ul_name);
998 	free(ul_name_desc);
999 	return 0;
1000 }
1001 
1002 /*
1003  * run_query_pager --
1004  *  Utility function similar to run_query_html. This function tries to
1005  *  pre-process the result assuming it will be piped to a pager.
1006  *  For this purpose it first calls its own callback function callback_pager
1007  *  which then delegates the call to the user supplied callback.
1008  */
1009 static int
1010 run_query_pager(sqlite3 *db, query_args *args)
1011 {
1012 	struct orig_callback_data orig_data;
1013 	orig_data.callback = args->callback;
1014 	orig_data.data = args->callback_data;
1015 	const char *snippet_args[3] = { "\002", "\003", "..." };
1016 	args->callback = &callback_pager;
1017 	args->callback_data = (void *) &orig_data;
1018 	return run_query_internal(db, snippet_args, args);
1019 }
1020 
1021 struct nv {
1022 	char *s;
1023 	size_t l;
1024 };
1025 
1026 static int
1027 term_putc(int c, void *p)
1028 {
1029 	struct nv *nv = p;
1030 	nv->s[nv->l++] = c;
1031 	return 0;
1032 }
1033 
1034 static char *
1035 term_fix_seq(TERMINAL *ti, const char *seq)
1036 {
1037 	char *res = estrdup(seq);
1038 	struct nv nv;
1039 
1040 	if (ti == NULL)
1041 	    return res;
1042 
1043 	nv.s = res;
1044 	nv.l = 0;
1045 	ti_puts(ti, seq, 1, term_putc, &nv);
1046 	nv.s[nv.l] = '\0';
1047 
1048 	return res;
1049 }
1050 
1051 static void
1052 term_init(int fd, const char *sa[5])
1053 {
1054 	TERMINAL *ti;
1055 	int error;
1056 	const char *bold, *sgr0, *smso, *rmso, *smul, *rmul;
1057 
1058 	if (ti_setupterm(&ti, NULL, fd, &error) == -1) {
1059 		bold = sgr0 = NULL;
1060 		smso = rmso = smul = rmul = "";
1061 		ti = NULL;
1062 	} else {
1063 		bold = ti_getstr(ti, "bold");
1064 		sgr0 = ti_getstr(ti, "sgr0");
1065 		if (bold == NULL || sgr0 == NULL) {
1066 			smso = ti_getstr(ti, "smso");
1067 
1068 			if (smso == NULL ||
1069 			    (rmso = ti_getstr(ti, "rmso")) == NULL)
1070 				smso = rmso = "";
1071 			bold = sgr0 = NULL;
1072 		} else
1073 			smso = rmso = "";
1074 
1075 		smul = ti_getstr(ti, "smul");
1076 		if (smul == NULL || (rmul = ti_getstr(ti, "rmul")) == NULL)
1077 			smul = rmul = "";
1078 	}
1079 
1080 	sa[0] = term_fix_seq(ti, bold ? bold : smso);
1081 	sa[1] = term_fix_seq(ti, sgr0 ? sgr0 : rmso);
1082 	sa[2] = estrdup("...");
1083 	sa[3] = term_fix_seq(ti, smul);
1084 	sa[4] = term_fix_seq(ti, rmul);
1085 
1086 	if (ti)
1087 		del_curterm(ti);
1088 }
1089 
1090 /*
1091  * run_query_term --
1092  *  Utility function similar to run_query_html. This function tries to
1093  *  pre-process the result assuming it will be displayed on a terminal
1094  *  For this purpose it first calls its own callback function callback_pager
1095  *  which then delegates the call to the user supplied callback.
1096  */
1097 static int
1098 run_query_term(sqlite3 *db, query_args *args)
1099 {
1100 	struct orig_callback_data orig_data;
1101 	struct term_args ta;
1102 	orig_data.callback = args->callback;
1103 	orig_data.data = args->callback_data;
1104 	const char *snippet_args[5];
1105 
1106 	term_init(STDOUT_FILENO, snippet_args);
1107 	ta.smul = snippet_args[3];
1108 	ta.rmul = snippet_args[4];
1109 	ta.orig_data = (void *) &orig_data;
1110 
1111 	args->callback = &callback_term;
1112 	args->callback_data = &ta;
1113 	return run_query_internal(db, snippet_args, args);
1114 }
1115 
1116 static int
1117 run_query_none(sqlite3 *db, query_args *args)
1118 {
1119 	struct orig_callback_data orig_data;
1120 	orig_data.callback = args->callback;
1121 	orig_data.data = args->callback_data;
1122 	const char *snippet_args[3] = { "", "", "..." };
1123 	args->callback = &callback_pager;
1124 	args->callback_data = (void *) &orig_data;
1125 	return run_query_internal(db, snippet_args, args);
1126 }
1127 
1128 int
1129 run_query(sqlite3 *db, query_format fmt, query_args *args)
1130 {
1131 	switch (fmt) {
1132 	case APROPOS_NONE:
1133 		return run_query_none(db, args);
1134 	case APROPOS_HTML:
1135 		return run_query_html(db, args);
1136 	case APROPOS_TERM:
1137 		return run_query_term(db, args);
1138 	case APROPOS_PAGER:
1139 		return run_query_pager(db, args);
1140 	default:
1141 		warnx("Unknown query format %d", (int)fmt);
1142 		return -1;
1143 	}
1144 }
1145