xref: /freebsd/sys/dev/vt/vt_font.c (revision 783d3ff6d7fae619db8a7990b8a6387de0c677b5)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2009 The FreeBSD Foundation
5  *
6  * This software was developed by Ed Schouten under sponsorship from the
7  * FreeBSD Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
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 the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/malloc.h>
34 #include <sys/refcount.h>
35 #include <sys/systm.h>
36 
37 #include <dev/vt/vt.h>
38 
39 static MALLOC_DEFINE(M_VTFONT, "vtfont", "vt font");
40 
41 /* Some limits to prevent abnormal fonts from being loaded. */
42 #define	VTFONT_MAXMAPPINGS	65536
43 #define	VTFONT_MAXGLYPHS	131072
44 #define	VTFONT_MAXGLYPHSIZE	2097152
45 #define	VTFONT_MAXDIMENSION	128
46 
47 static uint16_t
48 vtfont_bisearch(const vfnt_map_t *map, unsigned int len, uint32_t src)
49 {
50 	int min, mid, max;
51 
52 	min = 0;
53 	max = len - 1;
54 
55 	/* Empty font map. */
56 	if (len == 0)
57 		return (0);
58 	/* Character below minimal entry. */
59 	if (src < map[0].vfm_src)
60 		return (0);
61 	/* Optimization: ASCII characters occur very often. */
62 	if (src <= map[0].vfm_src + map[0].vfm_len)
63 		return (src - map[0].vfm_src + map[0].vfm_dst);
64 	/* Character above maximum entry. */
65 	if (src > map[max].vfm_src + map[max].vfm_len)
66 		return (0);
67 
68 	/* Binary search. */
69 	while (max >= min) {
70 		mid = (min + max) / 2;
71 		if (src < map[mid].vfm_src)
72 			max = mid - 1;
73 		else if (src > map[mid].vfm_src + map[mid].vfm_len)
74 			min = mid + 1;
75 		else
76 			return (src - map[mid].vfm_src + map[mid].vfm_dst);
77 	}
78 
79 	return (0);
80 }
81 
82 const uint8_t *
83 vtfont_lookup(const struct vt_font *vf, term_char_t c)
84 {
85 	uint32_t src;
86 	uint16_t dst;
87 	size_t stride;
88 	unsigned int normal_map;
89 	unsigned int bold_map;
90 
91 	src = TCHAR_CHARACTER(c);
92 	if (TCHAR_FORMAT(c) & TF_CJK_RIGHT) {
93 		normal_map = VFNT_MAP_NORMAL_RIGHT;
94 		bold_map = VFNT_MAP_BOLD_RIGHT;
95 	} else {
96 		normal_map = VFNT_MAP_NORMAL;
97 		bold_map = VFNT_MAP_BOLD;
98 	}
99 
100 	if (TCHAR_FORMAT(c) & TF_BOLD) {
101 		dst = vtfont_bisearch(vf->vf_map[bold_map],
102 		    vf->vf_map_count[bold_map], src);
103 		if (dst != 0)
104 			goto found;
105 	}
106 	dst = vtfont_bisearch(vf->vf_map[normal_map],
107 	    vf->vf_map_count[normal_map], src);
108 
109 found:
110 	stride = howmany(vf->vf_width, 8) * vf->vf_height;
111 	return (&vf->vf_bytes[dst * stride]);
112 }
113 
114 struct vt_font *
115 vtfont_ref(struct vt_font *vf)
116 {
117 
118 	refcount_acquire(&vf->vf_refcount);
119 	return (vf);
120 }
121 
122 void
123 vtfont_unref(struct vt_font *vf)
124 {
125 	unsigned int i;
126 
127 	if (refcount_release(&vf->vf_refcount)) {
128 		for (i = 0; i < VFNT_MAPS; i++)
129 			free(vf->vf_map[i], M_VTFONT);
130 		free(vf->vf_bytes, M_VTFONT);
131 		free(vf, M_VTFONT);
132 	}
133 }
134 
135 static int
136 vtfont_validate_map(vfnt_map_t *vfm, unsigned int length,
137     unsigned int glyph_count)
138 {
139 	unsigned int i, last = 0;
140 
141 	for (i = 0; i < length; i++) {
142 		/* Not ordered. */
143 		if (i > 0 && vfm[i].vfm_src <= last)
144 			return (EINVAL);
145 		/*
146 		 * Destination extends amount of glyphs.
147 		 */
148 		if (vfm[i].vfm_dst >= glyph_count ||
149 		    vfm[i].vfm_dst + vfm[i].vfm_len >= glyph_count)
150 			return (EINVAL);
151 		last = vfm[i].vfm_src + vfm[i].vfm_len;
152 	}
153 
154 	return (0);
155 }
156 
157 int
158 vtfont_load(vfnt_t *f, struct vt_font **ret)
159 {
160 	size_t glyphsize, mapsize;
161 	struct vt_font *vf;
162 	int error;
163 	unsigned int i;
164 
165 	/* Make sure the dimensions are valid. */
166 	if (f->width < 1 || f->height < 1)
167 		return (EINVAL);
168 	if (f->width > VTFONT_MAXDIMENSION || f->height > VTFONT_MAXDIMENSION ||
169 	    f->glyph_count > VTFONT_MAXGLYPHS)
170 		return (E2BIG);
171 
172 	/* Not too many mappings. */
173 	for (i = 0; i < VFNT_MAPS; i++)
174 		if (f->map_count[i] > VTFONT_MAXMAPPINGS)
175 			return (E2BIG);
176 
177 	/* Character 0 must always be present. */
178 	if (f->glyph_count < 1)
179 		return (EINVAL);
180 
181 	glyphsize = howmany(f->width, 8) * f->height * f->glyph_count;
182 	if (glyphsize > VTFONT_MAXGLYPHSIZE)
183 		return (E2BIG);
184 
185 	/* Allocate new font structure. */
186 	vf = malloc(sizeof *vf, M_VTFONT, M_WAITOK | M_ZERO);
187 	vf->vf_bytes = malloc(glyphsize, M_VTFONT, M_WAITOK);
188 	vf->vf_height = f->height;
189 	vf->vf_width = f->width;
190 	vf->vf_refcount = 1;
191 
192 	/* Allocate, copy in, and validate mappings. */
193 	for (i = 0; i < VFNT_MAPS; i++) {
194 		vf->vf_map_count[i] = f->map_count[i];
195 		if (f->map_count[i] == 0)
196 			continue;
197 		mapsize = f->map_count[i] * sizeof(vfnt_map_t);
198 		vf->vf_map[i] = malloc(mapsize, M_VTFONT, M_WAITOK);
199 		error = copyin(f->map[i], vf->vf_map[i], mapsize);
200 		if (error)
201 			goto bad;
202 		error = vtfont_validate_map(vf->vf_map[i], vf->vf_map_count[i],
203 		    f->glyph_count);
204 		if (error)
205 			goto bad;
206 	}
207 
208 	/* Copy in glyph data. */
209 	error = copyin(f->glyphs, vf->vf_bytes, glyphsize);
210 	if (error)
211 		goto bad;
212 
213 	/* Success. */
214 	*ret = vf;
215 	return (0);
216 
217 bad:	vtfont_unref(vf);
218 	return (error);
219 }
220