xref: /freebsd/sys/dev/vt/vt_font.c (revision cddbc3b40812213ff00041f79174cac0be360a2a)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2009 The FreeBSD Foundation
5  * All rights reserved.
6  *
7  * This software was developed by Ed Schouten under sponsorship from the
8  * FreeBSD Foundation.
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  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/refcount.h>
39 #include <sys/systm.h>
40 
41 #include <dev/vt/vt.h>
42 
43 static MALLOC_DEFINE(M_VTFONT, "vtfont", "vt font");
44 
45 /* Some limits to prevent abnormal fonts from being loaded. */
46 #define	VTFONT_MAXMAPPINGS	65536
47 #define	VTFONT_MAXGLYPHS	131072
48 #define	VTFONT_MAXGLYPHSIZE	2097152
49 #define	VTFONT_MAXDIMENSION	128
50 
51 static uint16_t
52 vtfont_bisearch(const struct vt_font_map *map, unsigned int len, uint32_t src)
53 {
54 	int min, mid, max;
55 
56 	min = 0;
57 	max = len - 1;
58 
59 	/* Empty font map. */
60 	if (len == 0)
61 		return (0);
62 	/* Character below minimal entry. */
63 	if (src < map[0].vfm_src)
64 		return (0);
65 	/* Optimization: ASCII characters occur very often. */
66 	if (src <= map[0].vfm_src + map[0].vfm_len)
67 		return (src - map[0].vfm_src + map[0].vfm_dst);
68 	/* Character above maximum entry. */
69 	if (src > map[max].vfm_src + map[max].vfm_len)
70 		return (0);
71 
72 	/* Binary search. */
73 	while (max >= min) {
74 		mid = (min + max) / 2;
75 		if (src < map[mid].vfm_src)
76 			max = mid - 1;
77 		else if (src > map[mid].vfm_src + map[mid].vfm_len)
78 			min = mid + 1;
79 		else
80 			return (src - map[mid].vfm_src + map[mid].vfm_dst);
81 	}
82 
83 	return (0);
84 }
85 
86 const uint8_t *
87 vtfont_lookup(const struct vt_font *vf, term_char_t c)
88 {
89 	uint32_t src;
90 	uint16_t dst;
91 	size_t stride;
92 	unsigned int normal_map;
93 	unsigned int bold_map;
94 
95 	/*
96 	 * No support for printing right hand sides for CJK fullwidth
97 	 * characters. Simply print a space and assume that the left
98 	 * hand side describes the entire character.
99 	 */
100 	src = TCHAR_CHARACTER(c);
101 	if (TCHAR_FORMAT(c) & TF_CJK_RIGHT) {
102 		normal_map = VFNT_MAP_NORMAL_RIGHT;
103 		bold_map = VFNT_MAP_BOLD_RIGHT;
104 	} else {
105 		normal_map = VFNT_MAP_NORMAL;
106 		bold_map = VFNT_MAP_BOLD;
107 	}
108 
109 	if (TCHAR_FORMAT(c) & TF_BOLD) {
110 		dst = vtfont_bisearch(vf->vf_map[bold_map],
111 		    vf->vf_map_count[bold_map], src);
112 		if (dst != 0)
113 			goto found;
114 	}
115 	dst = vtfont_bisearch(vf->vf_map[normal_map],
116 	    vf->vf_map_count[normal_map], src);
117 
118 found:
119 	stride = howmany(vf->vf_width, 8) * vf->vf_height;
120 	return (&vf->vf_bytes[dst * stride]);
121 }
122 
123 struct vt_font *
124 vtfont_ref(struct vt_font *vf)
125 {
126 
127 	refcount_acquire(&vf->vf_refcount);
128 	return (vf);
129 }
130 
131 void
132 vtfont_unref(struct vt_font *vf)
133 {
134 	unsigned int i;
135 
136 	if (refcount_release(&vf->vf_refcount)) {
137 		for (i = 0; i < VFNT_MAPS; i++)
138 			free(vf->vf_map[i], M_VTFONT);
139 		free(vf->vf_bytes, M_VTFONT);
140 		free(vf, M_VTFONT);
141 	}
142 }
143 
144 static int
145 vtfont_validate_map(struct vt_font_map *vfm, unsigned int length,
146     unsigned int glyph_count)
147 {
148 	unsigned int i, last = 0;
149 
150 	for (i = 0; i < length; i++) {
151 		/* Not ordered. */
152 		if (i > 0 && vfm[i].vfm_src <= last)
153 			return (EINVAL);
154 		/*
155 		 * Destination extends amount of glyphs.
156 		 */
157 		if (vfm[i].vfm_dst >= glyph_count ||
158 		    vfm[i].vfm_dst + vfm[i].vfm_len >= glyph_count)
159 			return (EINVAL);
160 		last = vfm[i].vfm_src + vfm[i].vfm_len;
161 	}
162 
163 	return (0);
164 }
165 
166 int
167 vtfont_load(vfnt_t *f, struct vt_font **ret)
168 {
169 	size_t glyphsize, mapsize;
170 	struct vt_font *vf;
171 	int error;
172 	unsigned int i;
173 
174 	/* Make sure the dimensions are valid. */
175 	if (f->width < 1 || f->height < 1)
176 		return (EINVAL);
177 	if (f->width > VTFONT_MAXDIMENSION || f->height > VTFONT_MAXDIMENSION ||
178 	    f->glyph_count > VTFONT_MAXGLYPHS)
179 		return (E2BIG);
180 
181 	/* Not too many mappings. */
182 	for (i = 0; i < VFNT_MAPS; i++)
183 		if (f->map_count[i] > VTFONT_MAXMAPPINGS)
184 			return (E2BIG);
185 
186 	/* Character 0 must always be present. */
187 	if (f->glyph_count < 1)
188 		return (EINVAL);
189 
190 	glyphsize = howmany(f->width, 8) * f->height * f->glyph_count;
191 	if (glyphsize > VTFONT_MAXGLYPHSIZE)
192 		return (E2BIG);
193 
194 	/* Allocate new font structure. */
195 	vf = malloc(sizeof *vf, M_VTFONT, M_WAITOK | M_ZERO);
196 	vf->vf_bytes = malloc(glyphsize, M_VTFONT, M_WAITOK);
197 	vf->vf_height = f->height;
198 	vf->vf_width = f->width;
199 	vf->vf_refcount = 1;
200 
201 	/* Allocate, copy in, and validate mappings. */
202 	for (i = 0; i < VFNT_MAPS; i++) {
203 		vf->vf_map_count[i] = f->map_count[i];
204 		if (f->map_count[i] == 0)
205 			continue;
206 		mapsize = f->map_count[i] * sizeof(struct vt_font_map);
207 		vf->vf_map[i] = malloc(mapsize, M_VTFONT, M_WAITOK);
208 		error = copyin(f->map[i], vf->vf_map[i], mapsize);
209 		if (error)
210 			goto bad;
211 		error = vtfont_validate_map(vf->vf_map[i], vf->vf_map_count[i],
212 		    f->glyph_count);
213 		if (error)
214 			goto bad;
215 	}
216 
217 	/* Copy in glyph data. */
218 	error = copyin(f->glyphs, vf->vf_bytes, glyphsize);
219 	if (error)
220 		goto bad;
221 
222 	/* Success. */
223 	*ret = vf;
224 	return (0);
225 
226 bad:	vtfont_unref(vf);
227 	return (error);
228 }
229