xref: /freebsd-13-stable/sys/dev/efidev/efidev.c (revision 3bc80996974a61a4223eae4c1ccd47b6ee32a48a)
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 #include <sys/param.h>
28 #include <sys/systm.h>
29 #include <sys/kernel.h>
30 #include <sys/bus.h>
31 #include <sys/conf.h>
32 #include <sys/lock.h>
33 #include <sys/malloc.h>
34 #include <sys/module.h>
35 
36 #include <machine/efi.h>
37 #include <sys/efiio.h>
38 
39 static d_ioctl_t efidev_ioctl;
40 
41 static struct cdevsw efi_cdevsw = {
42 	.d_name = "efi",
43 	.d_version = D_VERSION,
44 	.d_ioctl = efidev_ioctl,
45 };
46 
47 static int
efidev_ioctl(struct cdev * dev __unused,u_long cmd,caddr_t addr,int flags __unused,struct thread * td __unused)48 efidev_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr,
49     int flags __unused, struct thread *td __unused)
50 {
51 	int error;
52 
53 	switch (cmd) {
54 	case EFIIOC_GET_TIME:
55 	{
56 		struct efi_tm *tm = (struct efi_tm *)addr;
57 
58 		error = efi_get_time(tm);
59 		break;
60 	}
61 	case EFIIOC_SET_TIME:
62 	{
63 		struct efi_tm *tm = (struct efi_tm *)addr;
64 
65 		error = efi_set_time(tm);
66 		break;
67 	}
68 	case EFIIOC_VAR_GET:
69 	{
70 		struct efi_var_ioc *ev = (struct efi_var_ioc *)addr;
71 		void *data;
72 		efi_char *name;
73 
74 		data = malloc(ev->datasize, M_TEMP, M_WAITOK);
75 		name = malloc(ev->namesize, M_TEMP, M_WAITOK);
76 		error = copyin(ev->name, name, ev->namesize);
77 		if (error)
78 			goto vg_out;
79 		if (name[ev->namesize / sizeof(efi_char) - 1] != 0) {
80 			error = EINVAL;
81 			goto vg_out;
82 		}
83 
84 		error = efi_var_get(name, &ev->vendor, &ev->attrib,
85 		    &ev->datasize, data);
86 
87 		if (error == 0) {
88 			error = copyout(data, ev->data, ev->datasize);
89 		} else if (error == EOVERFLOW) {
90 			/*
91 			 * Pass back the size we really need, but
92 			 * convert the error to 0 so the copyout
93 			 * happens. datasize was updated in the
94 			 * efi_var_get call.
95 			 */
96 			ev->data = NULL;
97 			error = 0;
98 		}
99 vg_out:
100 		free(data, M_TEMP);
101 		free(name, M_TEMP);
102 		break;
103 	}
104 	case EFIIOC_VAR_NEXT:
105 	{
106 		struct efi_var_ioc *ev = (struct efi_var_ioc *)addr;
107 		efi_char *name;
108 
109 		name = malloc(ev->namesize, M_TEMP, M_WAITOK);
110 		error = copyin(ev->name, name, ev->namesize);
111 		if (error)
112 			goto vn_out;
113 		/* Note: namesize is the buffer size, not the string lenght */
114 
115 		error = efi_var_nextname(&ev->namesize, name, &ev->vendor);
116 		if (error == 0) {
117 			error = copyout(name, ev->name, ev->namesize);
118 		} else if (error == EOVERFLOW) {
119 			ev->name = NULL;
120 			error = 0;
121 		}
122 	vn_out:
123 		free(name, M_TEMP);
124 		break;
125 	}
126 	case EFIIOC_VAR_SET:
127 	{
128 		struct efi_var_ioc *ev = (struct efi_var_ioc *)addr;
129 		void *data = NULL;
130 		efi_char *name;
131 
132 		/* datasize == 0 -> delete (more or less) */
133 		if (ev->datasize > 0)
134 			data = malloc(ev->datasize, M_TEMP, M_WAITOK);
135 		name = malloc(ev->namesize, M_TEMP, M_WAITOK);
136 		if (ev->datasize) {
137 			error = copyin(ev->data, data, ev->datasize);
138 			if (error)
139 				goto vs_out;
140 		}
141 		error = copyin(ev->name, name, ev->namesize);
142 		if (error)
143 			goto vs_out;
144 		if (name[ev->namesize / sizeof(efi_char) - 1] != 0) {
145 			error = EINVAL;
146 			goto vs_out;
147 		}
148 
149 		error = efi_var_set(name, &ev->vendor, ev->attrib, ev->datasize,
150 		    data);
151 vs_out:
152 		free(data, M_TEMP);
153 		free(name, M_TEMP);
154 		break;
155 	}
156 	default:
157 		error = ENOTTY;
158 		break;
159 	}
160 
161 	return (error);
162 }
163 
164 static struct cdev *efidev;
165 
166 static int
efidev_modevents(module_t m,int event,void * arg __unused)167 efidev_modevents(module_t m, int event, void *arg __unused)
168 {
169 	struct make_dev_args mda;
170 	int error;
171 
172 	switch (event) {
173 	case MOD_LOAD:
174 		/*
175 		 * If we have no efi environment, then don't create the device.
176 		 */
177 		if (efi_rt_ok() != 0)
178 			return (0);
179 		make_dev_args_init(&mda);
180 		mda.mda_flags = MAKEDEV_WAITOK | MAKEDEV_CHECKNAME;
181 		mda.mda_devsw = &efi_cdevsw;
182 		mda.mda_uid = UID_ROOT;
183 		mda.mda_gid = GID_WHEEL;
184 		mda.mda_mode = 0700;
185 		error = make_dev_s(&mda, &efidev, "efi");
186 		return (error);
187 
188 	case MOD_UNLOAD:
189 		if (efidev != NULL)
190 			destroy_dev(efidev);
191 		efidev = NULL;
192 		return (0);
193 
194 	case MOD_SHUTDOWN:
195 		return (0);
196 
197 	default:
198 		return (EOPNOTSUPP);
199 	}
200 }
201 
202 static moduledata_t efidev_moddata = {
203 	.name = "efidev",
204 	.evhand = efidev_modevents,
205 	.priv = NULL,
206 };
207 
208 DECLARE_MODULE(efidev, efidev_moddata, SI_SUB_DRIVERS, SI_ORDER_ANY);
209 MODULE_VERSION(efidev, 1);
210 MODULE_DEPEND(efidev, efirt, 1, 1, 1);
211