1 /*
2 * srm_env.c - Access to SRM environment
3 * variables through linux' procfs
4 *
5 * Copyright (C) 2001-2002 Jan-Benedict Glaw <jbglaw@lug-owl.de>
6 *
7 * This driver is at all a modified version of Erik Mouw's
8 * ./linux/Documentation/DocBook/procfs_example.c, so: thank
9 * you, Erik! He can be reached via email at
10 * <J.A.K.Mouw@its.tudelft.nl>. It is based on an idea
11 * provided by DEC^WCompaq^WIntel's "Jumpstart" CD. They
12 * included a patch like this as well. Thanks for idea!
13 *
14 * This program is free software; you can redistribute
15 * it and/or modify it under the terms of the GNU General
16 * Public License version 2 as published by the Free Software
17 * Foundation.
18 *
19 * This program is distributed in the hope that it will be
20 * useful, but WITHOUT ANY WARRANTY; without even the implied
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
22 * PURPOSE. See the GNU General Public License for more
23 * details.
24 *
25 * You should have received a copy of the GNU General Public
26 * License along with this program; if not, write to the
27 * Free Software Foundation, Inc., 59 Temple Place,
28 * Suite 330, Boston, MA 02111-1307 USA
29 *
30 */
31
32 /*
33 * Changelog
34 * ~~~~~~~~~
35 *
36 * Thu, 22 Aug 2002 15:10:43 +0200
37 * - Update Config.help entry. I got a number of emails asking
38 * me to tell their senders if they could make use of this
39 * piece of code... So: "SRM is something like BIOS for your
40 * Alpha"
41 * - Update code formatting a bit to better conform CodingStyle
42 * rules.
43 * - So this is v0.0.5, with no changes (except formatting)
44 *
45 * Wed, 22 May 2002 00:11:21 +0200
46 * - Fix typo on comment (SRC -> SRM)
47 * - Call this "Version 0.0.4"
48 *
49 * Tue, 9 Apr 2002 18:44:40 +0200
50 * - Implement access by variable name and additionally
51 * by number. This is done by creating two subdirectories
52 * where one holds all names (like the old directory
53 * did) and the other holding 256 files named like "0",
54 * "1" and so on.
55 * - Call this "Version 0.0.3"
56 *
57 */
58
59 #include <linux/kernel.h>
60 #include <linux/config.h>
61 #include <linux/module.h>
62 #include <linux/init.h>
63 #include <linux/proc_fs.h>
64 #include <asm/console.h>
65 #include <asm/uaccess.h>
66 #include <asm/machvec.h>
67
68 #define BASE_DIR "srm_environment" /* Subdir in /proc/ */
69 #define NAMED_DIR "named_variables" /* Subdir for known variables */
70 #define NUMBERED_DIR "numbered_variables" /* Subdir for all variables */
71 #define VERSION "0.0.5" /* Module version */
72 #define NAME "srm_env" /* Module name */
73
74 MODULE_AUTHOR("Jan-Benedict Glaw <jbglaw@lug-owl.de>");
75 MODULE_DESCRIPTION("Accessing Alpha SRM environment through procfs interface");
76 MODULE_LICENSE("GPL");
77
78 typedef struct _srm_env {
79 char *name;
80 unsigned long id;
81 struct proc_dir_entry *proc_entry;
82 } srm_env_t;
83
84 static struct proc_dir_entry *base_dir;
85 static struct proc_dir_entry *named_dir;
86 static struct proc_dir_entry *numbered_dir;
87 static char number[256][4];
88
89 static srm_env_t srm_named_entries[] = {
90 { "auto_action", ENV_AUTO_ACTION },
91 { "boot_dev", ENV_BOOT_DEV },
92 { "bootdef_dev", ENV_BOOTDEF_DEV },
93 { "booted_dev", ENV_BOOTED_DEV },
94 { "boot_file", ENV_BOOT_FILE },
95 { "booted_file", ENV_BOOTED_FILE },
96 { "boot_osflags", ENV_BOOT_OSFLAGS },
97 { "booted_osflags", ENV_BOOTED_OSFLAGS },
98 { "boot_reset", ENV_BOOT_RESET },
99 { "dump_dev", ENV_DUMP_DEV },
100 { "enable_audit", ENV_ENABLE_AUDIT },
101 { "license", ENV_LICENSE },
102 { "char_set", ENV_CHAR_SET },
103 { "language", ENV_LANGUAGE },
104 { "tty_dev", ENV_TTY_DEV },
105 { NULL, 0 },
106 };
107 static srm_env_t srm_numbered_entries[256];
108
109
110
111 static int
srm_env_read(char * page,char ** start,off_t off,int count,int * eof,void * data)112 srm_env_read(char *page, char **start, off_t off, int count, int *eof,
113 void *data)
114 {
115 int nbytes;
116 unsigned long ret;
117 srm_env_t *entry;
118
119 MOD_INC_USE_COUNT;
120
121 if(off != 0) {
122 MOD_DEC_USE_COUNT;
123 return -EFAULT;
124 }
125
126 entry = (srm_env_t *) data;
127 ret = callback_getenv(entry->id, page, count);
128
129 if((ret >> 61) == 0)
130 nbytes = (int) ret;
131 else
132 nbytes = -EFAULT;
133
134 MOD_DEC_USE_COUNT;
135
136 return nbytes;
137 }
138
139
140 static int
srm_env_write(struct file * file,const char * buffer,unsigned long count,void * data)141 srm_env_write(struct file *file, const char *buffer, unsigned long count,
142 void *data)
143 {
144 #define BUFLEN 512
145 int nbytes;
146 srm_env_t *entry;
147 char buf[BUFLEN];
148 unsigned long ret1, ret2;
149
150 MOD_INC_USE_COUNT;
151
152 entry = (srm_env_t *) data;
153
154 nbytes = strlen(buffer) + 1;
155 if(nbytes > BUFLEN) {
156 MOD_DEC_USE_COUNT;
157 return -ENOMEM;
158 }
159
160 /* memcpy(aligned_buffer, buffer, nbytes) */
161
162 if(copy_from_user(buf, buffer, count)) {
163 MOD_DEC_USE_COUNT;
164 return -EFAULT;
165 }
166 buf[count] = 0x00;
167
168 ret1 = callback_setenv(entry->id, buf, count);
169 if((ret1 >> 61) == 0) {
170 do
171 ret2 = callback_save_env();
172 while((ret2 >> 61) == 1);
173 nbytes = (int) ret1;
174 } else
175 nbytes = -EFAULT;
176
177 MOD_DEC_USE_COUNT;
178
179 return nbytes;
180 }
181
182
183 static void
srm_env_cleanup(void)184 srm_env_cleanup(void)
185 {
186 srm_env_t *entry;
187 unsigned long var_num;
188
189 if(base_dir) {
190 /*
191 * Remove named entries
192 */
193 if(named_dir) {
194 entry = srm_named_entries;
195 while(entry->name != NULL && entry->id != 0) {
196 if(entry->proc_entry) {
197 remove_proc_entry(entry->name,
198 named_dir);
199 entry->proc_entry = NULL;
200 }
201 entry++;
202 }
203 remove_proc_entry(NAMED_DIR, base_dir);
204 }
205
206 /*
207 * Remove numbered entries
208 */
209 if(numbered_dir) {
210 for(var_num = 0; var_num <= 255; var_num++) {
211 entry = &srm_numbered_entries[var_num];
212
213 if(entry->proc_entry) {
214 remove_proc_entry(entry->name,
215 numbered_dir);
216 entry->proc_entry = NULL;
217 entry->name = NULL;
218 }
219 }
220 remove_proc_entry(NUMBERED_DIR, base_dir);
221 }
222
223 remove_proc_entry(BASE_DIR, NULL);
224 }
225
226 return;
227 }
228
229
230 static int __init
srm_env_init(void)231 srm_env_init(void)
232 {
233 srm_env_t *entry;
234 unsigned long var_num;
235
236 /*
237 * Check system
238 */
239 if(!alpha_using_srm) {
240 printk(KERN_INFO "%s: This Alpha system doesn't "
241 "know about SRM (or you've booted "
242 "SRM->MILO->Linux, which gets "
243 "misdetected)...\n", __FUNCTION__);
244 return -ENODEV;
245 }
246
247 /*
248 * Init numbers
249 */
250 for(var_num = 0; var_num <= 255; var_num++)
251 sprintf(number[var_num], "%ld", var_num);
252
253 /*
254 * Create base directory
255 */
256 base_dir = proc_mkdir(BASE_DIR, NULL);
257 if(base_dir == NULL) {
258 printk(KERN_ERR "Couldn't create base dir /proc/%s\n",
259 BASE_DIR);
260 goto cleanup;
261 }
262 base_dir->owner = THIS_MODULE;
263
264 /*
265 * Create per-name subdirectory
266 */
267 named_dir = proc_mkdir(NAMED_DIR, base_dir);
268 if(named_dir == NULL) {
269 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",
270 BASE_DIR, NAMED_DIR);
271 goto cleanup;
272 }
273 named_dir->owner = THIS_MODULE;
274
275 /*
276 * Create per-number subdirectory
277 */
278 numbered_dir = proc_mkdir(NUMBERED_DIR, base_dir);
279 if(numbered_dir == NULL) {
280 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",
281 BASE_DIR, NUMBERED_DIR);
282 goto cleanup;
283
284 }
285 numbered_dir->owner = THIS_MODULE;
286
287 /*
288 * Create all named nodes
289 */
290 entry = srm_named_entries;
291 while(entry->name != NULL && entry->id != 0) {
292 entry->proc_entry = create_proc_entry(entry->name,
293 0644, named_dir);
294 if(entry->proc_entry == NULL)
295 goto cleanup;
296
297 entry->proc_entry->data = (void *) entry;
298 entry->proc_entry->owner = THIS_MODULE;
299 entry->proc_entry->read_proc = srm_env_read;
300 entry->proc_entry->write_proc = srm_env_write;
301
302 entry++;
303 }
304
305 /*
306 * Create all numbered nodes
307 */
308 for(var_num = 0; var_num <= 255; var_num++) {
309 entry = &srm_numbered_entries[var_num];
310 entry->name = number[var_num];
311
312 entry->proc_entry = create_proc_entry(entry->name,
313 0644, numbered_dir);
314 if(entry->proc_entry == NULL)
315 goto cleanup;
316
317 entry->id = var_num;
318 entry->proc_entry->data = (void *) entry;
319 entry->proc_entry->owner = THIS_MODULE;
320 entry->proc_entry->read_proc = srm_env_read;
321 entry->proc_entry->write_proc = srm_env_write;
322 }
323
324 printk(KERN_INFO "%s: version %s loaded successfully\n", NAME,
325 VERSION);
326
327 return 0;
328
329 cleanup:
330 srm_env_cleanup();
331
332 return -ENOMEM;
333 }
334
335
336 static void __exit
srm_env_exit(void)337 srm_env_exit(void)
338 {
339 srm_env_cleanup();
340 printk(KERN_INFO "%s: unloaded successfully\n", NAME);
341
342 return;
343 }
344
345
346 module_init(srm_env_init);
347 module_exit(srm_env_exit);
348
349