1 /*
2 * srm_env.c - Access to SRM environment
3 * variables through linux' procfs
4 *
5 * (C) 2001,2002,2006 by Jan-Benedict Glaw <jbglaw@lug-owl.de>
6 *
7 * This driver is at all a modified version of Erik Mouw's
8 * 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 #include <linux/kernel.h>
33 #include <linux/gfp.h>
34 #include <linux/module.h>
35 #include <linux/init.h>
36 #include <linux/proc_fs.h>
37 #include <linux/seq_file.h>
38 #include <asm/console.h>
39 #include <asm/uaccess.h>
40 #include <asm/machvec.h>
41
42 #define BASE_DIR "srm_environment" /* Subdir in /proc/ */
43 #define NAMED_DIR "named_variables" /* Subdir for known variables */
44 #define NUMBERED_DIR "numbered_variables" /* Subdir for all variables */
45 #define VERSION "0.0.6" /* Module version */
46 #define NAME "srm_env" /* Module name */
47
48 MODULE_AUTHOR("Jan-Benedict Glaw <jbglaw@lug-owl.de>");
49 MODULE_DESCRIPTION("Accessing Alpha SRM environment through procfs interface");
50 MODULE_LICENSE("GPL");
51
52 typedef struct _srm_env {
53 char *name;
54 unsigned long id;
55 struct proc_dir_entry *proc_entry;
56 } srm_env_t;
57
58 static struct proc_dir_entry *base_dir;
59 static struct proc_dir_entry *named_dir;
60 static struct proc_dir_entry *numbered_dir;
61 static char number[256][4];
62
63 static srm_env_t srm_named_entries[] = {
64 { "auto_action", ENV_AUTO_ACTION },
65 { "boot_dev", ENV_BOOT_DEV },
66 { "bootdef_dev", ENV_BOOTDEF_DEV },
67 { "booted_dev", ENV_BOOTED_DEV },
68 { "boot_file", ENV_BOOT_FILE },
69 { "booted_file", ENV_BOOTED_FILE },
70 { "boot_osflags", ENV_BOOT_OSFLAGS },
71 { "booted_osflags", ENV_BOOTED_OSFLAGS },
72 { "boot_reset", ENV_BOOT_RESET },
73 { "dump_dev", ENV_DUMP_DEV },
74 { "enable_audit", ENV_ENABLE_AUDIT },
75 { "license", ENV_LICENSE },
76 { "char_set", ENV_CHAR_SET },
77 { "language", ENV_LANGUAGE },
78 { "tty_dev", ENV_TTY_DEV },
79 { NULL, 0 },
80 };
81 static srm_env_t srm_numbered_entries[256];
82
83
srm_env_proc_show(struct seq_file * m,void * v)84 static int srm_env_proc_show(struct seq_file *m, void *v)
85 {
86 unsigned long ret;
87 srm_env_t *entry;
88 char *page;
89
90 entry = m->private;
91 page = (char *)__get_free_page(GFP_USER);
92 if (!page)
93 return -ENOMEM;
94
95 ret = callback_getenv(entry->id, page, PAGE_SIZE);
96
97 if ((ret >> 61) == 0) {
98 seq_write(m, page, ret);
99 ret = 0;
100 } else
101 ret = -EFAULT;
102 free_page((unsigned long)page);
103 return ret;
104 }
105
srm_env_proc_open(struct inode * inode,struct file * file)106 static int srm_env_proc_open(struct inode *inode, struct file *file)
107 {
108 return single_open(file, srm_env_proc_show, PDE(inode)->data);
109 }
110
srm_env_proc_write(struct file * file,const char __user * buffer,size_t count,loff_t * pos)111 static ssize_t srm_env_proc_write(struct file *file, const char __user *buffer,
112 size_t count, loff_t *pos)
113 {
114 int res;
115 srm_env_t *entry = PDE(file->f_path.dentry->d_inode)->data;
116 char *buf = (char *) __get_free_page(GFP_USER);
117 unsigned long ret1, ret2;
118
119 if (!buf)
120 return -ENOMEM;
121
122 res = -EINVAL;
123 if (count >= PAGE_SIZE)
124 goto out;
125
126 res = -EFAULT;
127 if (copy_from_user(buf, buffer, count))
128 goto out;
129 buf[count] = '\0';
130
131 ret1 = callback_setenv(entry->id, buf, count);
132 if ((ret1 >> 61) == 0) {
133 do
134 ret2 = callback_save_env();
135 while((ret2 >> 61) == 1);
136 res = (int) ret1;
137 }
138
139 out:
140 free_page((unsigned long)buf);
141 return res;
142 }
143
144 static const struct file_operations srm_env_proc_fops = {
145 .owner = THIS_MODULE,
146 .open = srm_env_proc_open,
147 .read = seq_read,
148 .llseek = seq_lseek,
149 .release = single_release,
150 .write = srm_env_proc_write,
151 };
152
153 static void
srm_env_cleanup(void)154 srm_env_cleanup(void)
155 {
156 srm_env_t *entry;
157 unsigned long var_num;
158
159 if (base_dir) {
160 /*
161 * Remove named entries
162 */
163 if (named_dir) {
164 entry = srm_named_entries;
165 while (entry->name != NULL && entry->id != 0) {
166 if (entry->proc_entry) {
167 remove_proc_entry(entry->name,
168 named_dir);
169 entry->proc_entry = NULL;
170 }
171 entry++;
172 }
173 remove_proc_entry(NAMED_DIR, base_dir);
174 }
175
176 /*
177 * Remove numbered entries
178 */
179 if (numbered_dir) {
180 for (var_num = 0; var_num <= 255; var_num++) {
181 entry = &srm_numbered_entries[var_num];
182
183 if (entry->proc_entry) {
184 remove_proc_entry(entry->name,
185 numbered_dir);
186 entry->proc_entry = NULL;
187 entry->name = NULL;
188 }
189 }
190 remove_proc_entry(NUMBERED_DIR, base_dir);
191 }
192
193 remove_proc_entry(BASE_DIR, NULL);
194 }
195
196 return;
197 }
198
199 static int __init
srm_env_init(void)200 srm_env_init(void)
201 {
202 srm_env_t *entry;
203 unsigned long var_num;
204
205 /*
206 * Check system
207 */
208 if (!alpha_using_srm) {
209 printk(KERN_INFO "%s: This Alpha system doesn't "
210 "know about SRM (or you've booted "
211 "SRM->MILO->Linux, which gets "
212 "misdetected)...\n", __func__);
213 return -ENODEV;
214 }
215
216 /*
217 * Init numbers
218 */
219 for (var_num = 0; var_num <= 255; var_num++)
220 sprintf(number[var_num], "%ld", var_num);
221
222 /*
223 * Create base directory
224 */
225 base_dir = proc_mkdir(BASE_DIR, NULL);
226 if (!base_dir) {
227 printk(KERN_ERR "Couldn't create base dir /proc/%s\n",
228 BASE_DIR);
229 goto cleanup;
230 }
231
232 /*
233 * Create per-name subdirectory
234 */
235 named_dir = proc_mkdir(NAMED_DIR, base_dir);
236 if (!named_dir) {
237 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",
238 BASE_DIR, NAMED_DIR);
239 goto cleanup;
240 }
241
242 /*
243 * Create per-number subdirectory
244 */
245 numbered_dir = proc_mkdir(NUMBERED_DIR, base_dir);
246 if (!numbered_dir) {
247 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",
248 BASE_DIR, NUMBERED_DIR);
249 goto cleanup;
250
251 }
252
253 /*
254 * Create all named nodes
255 */
256 entry = srm_named_entries;
257 while (entry->name && entry->id) {
258 entry->proc_entry = proc_create_data(entry->name, 0644, named_dir,
259 &srm_env_proc_fops, entry);
260 if (!entry->proc_entry)
261 goto cleanup;
262 entry++;
263 }
264
265 /*
266 * Create all numbered nodes
267 */
268 for (var_num = 0; var_num <= 255; var_num++) {
269 entry = &srm_numbered_entries[var_num];
270 entry->name = number[var_num];
271
272 entry->proc_entry = proc_create_data(entry->name, 0644, numbered_dir,
273 &srm_env_proc_fops, entry);
274 if (!entry->proc_entry)
275 goto cleanup;
276
277 entry->id = var_num;
278 }
279
280 printk(KERN_INFO "%s: version %s loaded successfully\n", NAME,
281 VERSION);
282
283 return 0;
284
285 cleanup:
286 srm_env_cleanup();
287
288 return -ENOMEM;
289 }
290
291 static void __exit
srm_env_exit(void)292 srm_env_exit(void)
293 {
294 srm_env_cleanup();
295 printk(KERN_INFO "%s: unloaded successfully\n", NAME);
296
297 return;
298 }
299
300 module_init(srm_env_init);
301 module_exit(srm_env_exit);
302