xref: /freebsd/sys/dev/efidev/efidev.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * Copyright (c) 2016 Netflix, Inc.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer
9  *    in this position and unchanged.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28 
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/kernel.h>
32 #include <sys/bus.h>
33 #include <sys/conf.h>
34 #include <sys/lock.h>
35 #include <sys/malloc.h>
36 #include <sys/module.h>
37 
38 #include <machine/efi.h>
39 #include <sys/efiio.h>
40 
41 static d_ioctl_t efidev_ioctl;
42 
43 static struct cdevsw efi_cdevsw = {
44 	.d_name = "efi",
45 	.d_version = D_VERSION,
46 	.d_ioctl = efidev_ioctl,
47 };
48 
49 static int
50 efidev_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr,
51     int flags __unused, struct thread *td __unused)
52 {
53 	int error;
54 
55 	switch (cmd) {
56 	case EFIIOC_GET_TIME:
57 	{
58 		struct efi_tm *tm = (struct efi_tm *)addr;
59 
60 		error = efi_get_time(tm);
61 		break;
62 	}
63 	case EFIIOC_SET_TIME:
64 	{
65 		struct efi_tm *tm = (struct efi_tm *)addr;
66 
67 		error = efi_set_time(tm);
68 		break;
69 	}
70 	case EFIIOC_VAR_GET:
71 	{
72 		struct efi_var_ioc *ev = (struct efi_var_ioc *)addr;
73 		void *data;
74 		efi_char *name;
75 
76 		data = malloc(ev->datasize, M_TEMP, M_WAITOK);
77 		name = malloc(ev->namesize, M_TEMP, M_WAITOK);
78 		error = copyin(ev->name, name, ev->namesize);
79 		if (error)
80 			goto vg_out;
81 		if (name[ev->namesize / sizeof(efi_char) - 1] != 0) {
82 			error = EINVAL;
83 			goto vg_out;
84 		}
85 
86 		error = efi_var_get(name, &ev->vendor, &ev->attrib,
87 		    &ev->datasize, data);
88 
89 		if (error == 0) {
90 			error = copyout(data, ev->data, ev->datasize);
91 		} else if (error == EOVERFLOW) {
92 			/*
93 			 * Pass back the size we really need, but
94 			 * convert the error to 0 so the copyout
95 			 * happens. datasize was updated in the
96 			 * efi_var_get call.
97 			 */
98 			ev->data = NULL;
99 			error = 0;
100 		}
101 vg_out:
102 		free(data, M_TEMP);
103 		free(name, M_TEMP);
104 		break;
105 	}
106 	case EFIIOC_VAR_NEXT:
107 	{
108 		struct efi_var_ioc *ev = (struct efi_var_ioc *)addr;
109 		efi_char *name;
110 
111 		name = malloc(ev->namesize, M_TEMP, M_WAITOK);
112 		error = copyin(ev->name, name, ev->namesize);
113 		if (error)
114 			goto vn_out;
115 		/* Note: namesize is the buffer size, not the string lenght */
116 
117 		error = efi_var_nextname(&ev->namesize, name, &ev->vendor);
118 		if (error == 0) {
119 			error = copyout(name, ev->name, ev->namesize);
120 		} else if (error == EOVERFLOW) {
121 			ev->name = NULL;
122 			error = 0;
123 		}
124 	vn_out:
125 		free(name, M_TEMP);
126 		break;
127 	}
128 	case EFIIOC_VAR_SET:
129 	{
130 		struct efi_var_ioc *ev = (struct efi_var_ioc *)addr;
131 		void *data = NULL;
132 		efi_char *name;
133 
134 		/* datasize == 0 -> delete (more or less) */
135 		if (ev->datasize > 0)
136 			data = malloc(ev->datasize, M_TEMP, M_WAITOK);
137 		name = malloc(ev->namesize, M_TEMP, M_WAITOK);
138 		if (ev->datasize) {
139 			error = copyin(ev->data, data, ev->datasize);
140 			if (error)
141 				goto vs_out;
142 		}
143 		error = copyin(ev->name, name, ev->namesize);
144 		if (error)
145 			goto vs_out;
146 		if (name[ev->namesize / sizeof(efi_char) - 1] != 0) {
147 			error = EINVAL;
148 			goto vs_out;
149 		}
150 
151 		error = efi_var_set(name, &ev->vendor, ev->attrib, ev->datasize,
152 		    data);
153 vs_out:
154 		free(data, M_TEMP);
155 		free(name, M_TEMP);
156 		break;
157 	}
158 	default:
159 		error = ENOTTY;
160 		break;
161 	}
162 
163 	return (error);
164 }
165 
166 static struct cdev *efidev;
167 
168 static int
169 efidev_modevents(module_t m, int event, void *arg __unused)
170 {
171 	struct make_dev_args mda;
172 	int error;
173 
174 	switch (event) {
175 	case MOD_LOAD:
176 		/*
177 		 * If we have no efi environment, then don't create the device.
178 		 */
179 		if (efi_rt_ok() != 0)
180 			return (0);
181 		make_dev_args_init(&mda);
182 		mda.mda_flags = MAKEDEV_WAITOK | MAKEDEV_CHECKNAME;
183 		mda.mda_devsw = &efi_cdevsw;
184 		mda.mda_uid = UID_ROOT;
185 		mda.mda_gid = GID_WHEEL;
186 		mda.mda_mode = 0700;
187 		error = make_dev_s(&mda, &efidev, "efi");
188 		return (error);
189 
190 	case MOD_UNLOAD:
191 		if (efidev != NULL)
192 			destroy_dev(efidev);
193 		efidev = NULL;
194 		return (0);
195 
196 	case MOD_SHUTDOWN:
197 		return (0);
198 
199 	default:
200 		return (EOPNOTSUPP);
201 	}
202 }
203 
204 static moduledata_t efidev_moddata = {
205 	.name = "efidev",
206 	.evhand = efidev_modevents,
207 	.priv = NULL,
208 };
209 
210 DECLARE_MODULE(efidev, efidev_moddata, SI_SUB_DRIVERS, SI_ORDER_ANY);
211 MODULE_VERSION(efidev, 1);
212 MODULE_DEPEND(efidev, efirt, 1, 1, 1);
213