xref: /freebsd/contrib/mandoc/tag.c (revision c93b6e5fa24ba172ab271432c6692f9cc604e15a)
1 /*	$Id: tag.c,v 1.21 2018/11/22 11:30:23 schwarze Exp $ */
2 /*
3  * Copyright (c) 2015, 2016, 2018 Ingo Schwarze <schwarze@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 #include "config.h"
18 
19 #include <sys/types.h>
20 
21 #if HAVE_ERR
22 #include <err.h>
23 #endif
24 #include <limits.h>
25 #include <signal.h>
26 #include <stddef.h>
27 #include <stdint.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include "mandoc_aux.h"
34 #include "mandoc_ohash.h"
35 #include "tag.h"
36 
37 struct tag_entry {
38 	size_t	*lines;
39 	size_t	 maxlines;
40 	size_t	 nlines;
41 	int	 prio;
42 	char	 s[];
43 };
44 
45 static	void	 tag_signal(int) __attribute__((__noreturn__));
46 
47 static struct ohash	 tag_data;
48 static struct tag_files	 tag_files;
49 
50 
51 /*
52  * Prepare for using a pager.
53  * Not all pagers are capable of using a tag file,
54  * but for simplicity, create it anyway.
55  */
56 struct tag_files *
57 tag_init(void)
58 {
59 	struct sigaction	 sa;
60 	int			 ofd;
61 
62 	ofd = -1;
63 	tag_files.tfd = -1;
64 	tag_files.tcpgid = -1;
65 
66 	/* Clean up when dying from a signal. */
67 
68 	memset(&sa, 0, sizeof(sa));
69 	sigfillset(&sa.sa_mask);
70 	sa.sa_handler = tag_signal;
71 	sigaction(SIGHUP, &sa, NULL);
72 	sigaction(SIGINT, &sa, NULL);
73 	sigaction(SIGTERM, &sa, NULL);
74 
75 	/*
76 	 * POSIX requires that a process calling tcsetpgrp(3)
77 	 * from the background gets a SIGTTOU signal.
78 	 * In that case, do not stop.
79 	 */
80 
81 	sa.sa_handler = SIG_IGN;
82 	sigaction(SIGTTOU, &sa, NULL);
83 
84 	/* Save the original standard output for use by the pager. */
85 
86 	if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1)
87 		goto fail;
88 
89 	/* Create both temporary output files. */
90 
91 	(void)strlcpy(tag_files.ofn, "/tmp/man.XXXXXXXXXX",
92 	    sizeof(tag_files.ofn));
93 	(void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
94 	    sizeof(tag_files.tfn));
95 	if ((ofd = mkstemp(tag_files.ofn)) == -1)
96 		goto fail;
97 	if ((tag_files.tfd = mkstemp(tag_files.tfn)) == -1)
98 		goto fail;
99 	if (dup2(ofd, STDOUT_FILENO) == -1)
100 		goto fail;
101 	close(ofd);
102 
103 	/*
104 	 * Set up the ohash table to collect output line numbers
105 	 * where various marked-up terms are documented.
106 	 */
107 
108 	mandoc_ohash_init(&tag_data, 4, offsetof(struct tag_entry, s));
109 	return &tag_files;
110 
111 fail:
112 	tag_unlink();
113 	if (ofd != -1)
114 		close(ofd);
115 	if (tag_files.ofd != -1)
116 		close(tag_files.ofd);
117 	if (tag_files.tfd != -1)
118 		close(tag_files.tfd);
119 	*tag_files.ofn = '\0';
120 	*tag_files.tfn = '\0';
121 	tag_files.ofd = -1;
122 	tag_files.tfd = -1;
123 	return NULL;
124 }
125 
126 /*
127  * Set the line number where a term is defined,
128  * unless it is already defined at a lower priority.
129  */
130 void
131 tag_put(const char *s, int prio, size_t line)
132 {
133 	struct tag_entry	*entry;
134 	const char		*se;
135 	size_t			 len;
136 	unsigned int		 slot;
137 
138 	if (tag_files.tfd <= 0)
139 		return;
140 
141 	if (s[0] == '\\' && (s[1] == '&' || s[1] == 'e'))
142 		s += 2;
143 
144 	/*
145 	 * Skip whitespace and whatever follows it,
146 	 * and if there is any, downgrade the priority.
147 	 */
148 
149 	len = strcspn(s, " \t");
150 	if (len == 0)
151 		return;
152 
153 	se = s + len;
154 	if (*se != '\0')
155 		prio = INT_MAX;
156 
157 	slot = ohash_qlookupi(&tag_data, s, &se);
158 	entry = ohash_find(&tag_data, slot);
159 
160 	if (entry == NULL) {
161 
162 		/* Build a new entry. */
163 
164 		entry = mandoc_malloc(sizeof(*entry) + len + 1);
165 		memcpy(entry->s, s, len);
166 		entry->s[len] = '\0';
167 		entry->lines = NULL;
168 		entry->maxlines = entry->nlines = 0;
169 		ohash_insert(&tag_data, slot, entry);
170 
171 	} else {
172 
173 		/*
174 		 * Lower priority numbers take precedence,
175 		 * but 0 is special.
176 		 * A tag with priority 0 is only used
177 		 * if the tag occurs exactly once.
178 		 */
179 
180 		if (prio == 0) {
181 			if (entry->prio == 0)
182 				entry->prio = -1;
183 			return;
184 		}
185 
186 		/* A better entry is already present, ignore the new one. */
187 
188 		if (entry->prio > 0 && entry->prio < prio)
189 			return;
190 
191 		/* The existing entry is worse, clear it. */
192 
193 		if (entry->prio < 1 || entry->prio > prio)
194 			entry->nlines = 0;
195 	}
196 
197 	/* Remember the new line. */
198 
199 	if (entry->maxlines == entry->nlines) {
200 		entry->maxlines += 4;
201 		entry->lines = mandoc_reallocarray(entry->lines,
202 		    entry->maxlines, sizeof(*entry->lines));
203 	}
204 	entry->lines[entry->nlines++] = line;
205 	entry->prio = prio;
206 }
207 
208 /*
209  * Write out the tags file using the previously collected
210  * information and clear the ohash table while going along.
211  */
212 void
213 tag_write(void)
214 {
215 	FILE			*stream;
216 	struct tag_entry	*entry;
217 	size_t			 i;
218 	unsigned int		 slot;
219 
220 	if (tag_files.tfd <= 0)
221 		return;
222 	if (tag_files.tagname != NULL && ohash_find(&tag_data,
223             ohash_qlookup(&tag_data, tag_files.tagname)) == NULL) {
224 		warnx("%s: no such tag", tag_files.tagname);
225 		tag_files.tagname = NULL;
226 	}
227 	stream = fdopen(tag_files.tfd, "w");
228 	entry = ohash_first(&tag_data, &slot);
229 	while (entry != NULL) {
230 		if (stream != NULL && entry->prio >= 0)
231 			for (i = 0; i < entry->nlines; i++)
232 				fprintf(stream, "%s %s %zu\n",
233 				    entry->s, tag_files.ofn, entry->lines[i]);
234 		free(entry->lines);
235 		free(entry);
236 		entry = ohash_next(&tag_data, &slot);
237 	}
238 	ohash_delete(&tag_data);
239 	if (stream != NULL)
240 		fclose(stream);
241 	else
242 		close(tag_files.tfd);
243 	tag_files.tfd = -1;
244 }
245 
246 void
247 tag_unlink(void)
248 {
249 	pid_t	 tc_pgid;
250 
251 	if (tag_files.tcpgid != -1) {
252 		tc_pgid = tcgetpgrp(tag_files.ofd);
253 		if (tc_pgid == tag_files.pager_pid ||
254 		    tc_pgid == getpgid(0) ||
255 		    getpgid(tc_pgid) == -1)
256 			(void)tcsetpgrp(tag_files.ofd, tag_files.tcpgid);
257 	}
258 	if (*tag_files.ofn != '\0')
259 		unlink(tag_files.ofn);
260 	if (*tag_files.tfn != '\0')
261 		unlink(tag_files.tfn);
262 }
263 
264 static void
265 tag_signal(int signum)
266 {
267 	struct sigaction	 sa;
268 
269 	tag_unlink();
270 	memset(&sa, 0, sizeof(sa));
271 	sigemptyset(&sa.sa_mask);
272 	sa.sa_handler = SIG_DFL;
273 	sigaction(signum, &sa, NULL);
274 	kill(getpid(), signum);
275 	/* NOTREACHED */
276 	_exit(1);
277 }
278