1/*	$Id: tag.c,v 1.18 2017/02/17 14:31:52 schwarze Exp $ */
2/*
3 * Copyright (c) 2015, 2016 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#include <signal.h>
22#include <stddef.h>
23#include <stdint.h>
24#include <stdio.h>
25#include <stdlib.h>
26#include <string.h>
27#include <unistd.h>
28
29#include "mandoc_aux.h"
30#include "mandoc_ohash.h"
31#include "tag.h"
32
33struct tag_entry {
34	size_t	*lines;
35	size_t	 maxlines;
36	size_t	 nlines;
37	int	 prio;
38	char	 s[];
39};
40
41static	void	 tag_signal(int) __attribute__((__noreturn__));
42
43static struct ohash	 tag_data;
44static struct tag_files	 tag_files;
45
46
47/*
48 * Prepare for using a pager.
49 * Not all pagers are capable of using a tag file,
50 * but for simplicity, create it anyway.
51 */
52struct tag_files *
53tag_init(void)
54{
55	struct sigaction	 sa;
56	int			 ofd;
57
58	ofd = -1;
59	tag_files.tfd = -1;
60	tag_files.tcpgid = -1;
61
62	/* Clean up when dying from a signal. */
63
64	memset(&sa, 0, sizeof(sa));
65	sigfillset(&sa.sa_mask);
66	sa.sa_handler = tag_signal;
67	sigaction(SIGHUP, &sa, NULL);
68	sigaction(SIGINT, &sa, NULL);
69	sigaction(SIGTERM, &sa, NULL);
70
71	/*
72	 * POSIX requires that a process calling tcsetpgrp(3)
73	 * from the background gets a SIGTTOU signal.
74	 * In that case, do not stop.
75	 */
76
77	sa.sa_handler = SIG_IGN;
78	sigaction(SIGTTOU, &sa, NULL);
79
80	/* Save the original standard output for use by the pager. */
81
82	if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1)
83		goto fail;
84
85	/* Create both temporary output files. */
86
87	(void)strlcpy(tag_files.ofn, "/tmp/man.XXXXXXXXXX",
88	    sizeof(tag_files.ofn));
89	(void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
90	    sizeof(tag_files.tfn));
91	if ((ofd = mkstemp(tag_files.ofn)) == -1)
92		goto fail;
93	if ((tag_files.tfd = mkstemp(tag_files.tfn)) == -1)
94		goto fail;
95	if (dup2(ofd, STDOUT_FILENO) == -1)
96		goto fail;
97	close(ofd);
98
99	/*
100	 * Set up the ohash table to collect output line numbers
101	 * where various marked-up terms are documented.
102	 */
103
104	mandoc_ohash_init(&tag_data, 4, offsetof(struct tag_entry, s));
105	return &tag_files;
106
107fail:
108	tag_unlink();
109	if (ofd != -1)
110		close(ofd);
111	if (tag_files.ofd != -1)
112		close(tag_files.ofd);
113	if (tag_files.tfd != -1)
114		close(tag_files.tfd);
115	*tag_files.ofn = '\0';
116	*tag_files.tfn = '\0';
117	tag_files.ofd = -1;
118	tag_files.tfd = -1;
119	return NULL;
120}
121
122/*
123 * Set the line number where a term is defined,
124 * unless it is already defined at a higher priority.
125 */
126void
127tag_put(const char *s, int prio, size_t line)
128{
129	struct tag_entry	*entry;
130	size_t			 len;
131	unsigned int		 slot;
132
133	/* Sanity checks. */
134
135	if (tag_files.tfd <= 0)
136		return;
137	if (s[0] == '\\' && (s[1] == '&' || s[1] == 'e'))
138		s += 2;
139	if (*s == '\0' || strchr(s, ' ') != NULL)
140		return;
141
142	slot = ohash_qlookup(&tag_data, s);
143	entry = ohash_find(&tag_data, slot);
144
145	if (entry == NULL) {
146
147		/* Build a new entry. */
148
149		len = strlen(s) + 1;
150		entry = mandoc_malloc(sizeof(*entry) + len);
151		memcpy(entry->s, s, len);
152		entry->lines = NULL;
153		entry->maxlines = entry->nlines = 0;
154		ohash_insert(&tag_data, slot, entry);
155
156	} else {
157
158		/* Handle priority 0 entries. */
159
160		if (prio == 0) {
161			if (entry->prio == 0)
162				entry->prio = -1;
163			return;
164		}
165
166		/* A better entry is already present, ignore the new one. */
167
168		if (entry->prio > 0 && entry->prio < prio)
169			return;
170
171		/* The existing entry is worse, clear it. */
172
173		if (entry->prio < 1 || entry->prio > prio)
174			entry->nlines = 0;
175	}
176
177	/* Remember the new line. */
178
179	if (entry->maxlines == entry->nlines) {
180		entry->maxlines += 4;
181		entry->lines = mandoc_reallocarray(entry->lines,
182		    entry->maxlines, sizeof(*entry->lines));
183	}
184	entry->lines[entry->nlines++] = line;
185	entry->prio = prio;
186}
187
188/*
189 * Write out the tags file using the previously collected
190 * information and clear the ohash table while going along.
191 */
192void
193tag_write(void)
194{
195	FILE			*stream;
196	struct tag_entry	*entry;
197	size_t			 i;
198	unsigned int		 slot;
199
200	if (tag_files.tfd <= 0)
201		return;
202	stream = fdopen(tag_files.tfd, "w");
203	entry = ohash_first(&tag_data, &slot);
204	while (entry != NULL) {
205		if (stream != NULL && entry->prio >= 0)
206			for (i = 0; i < entry->nlines; i++)
207				fprintf(stream, "%s %s %zu\n",
208				    entry->s, tag_files.ofn, entry->lines[i]);
209		free(entry->lines);
210		free(entry);
211		entry = ohash_next(&tag_data, &slot);
212	}
213	ohash_delete(&tag_data);
214	if (stream != NULL)
215		fclose(stream);
216}
217
218void
219tag_unlink(void)
220{
221	pid_t	 tc_pgid;
222
223	if (tag_files.tcpgid != -1) {
224		tc_pgid = tcgetpgrp(tag_files.ofd);
225		if (tc_pgid == tag_files.pager_pid ||
226		    tc_pgid == getpgid(0) ||
227		    getpgid(tc_pgid) == -1)
228			(void)tcsetpgrp(tag_files.ofd, tag_files.tcpgid);
229	}
230	if (*tag_files.ofn != '\0')
231		unlink(tag_files.ofn);
232	if (*tag_files.tfn != '\0')
233		unlink(tag_files.tfn);
234}
235
236static void
237tag_signal(int signum)
238{
239	struct sigaction	 sa;
240
241	tag_unlink();
242	memset(&sa, 0, sizeof(sa));
243	sigemptyset(&sa.sa_mask);
244	sa.sa_handler = SIG_DFL;
245	sigaction(signum, &sa, NULL);
246	kill(getpid(), signum);
247	/* NOTREACHED */
248	_exit(1);
249}
250