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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 a modified version of Erik Mouw's example proc
8 * interface, so: thank you, Erik! He can be reached via email at
9 * <J.A.K.Mouw@its.tudelft.nl>. It is based on an idea
10 * provided by DEC^WCompaq^WIntel's "Jumpstart" CD. They
11 * included a patch like this as well. Thanks for idea!
12 *
13 * This program is free software; you can redistribute
14 * it and/or modify it under the terms of the GNU General
15 * Public License version 2 as published by the Free Software
16 * Foundation.
17 *
18 * This program is distributed in the hope that it will be
19 * useful, but WITHOUT ANY WARRANTY; without even the implied
20 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
21 * PURPOSE. See the GNU General Public License for more
22 * details.
23 *
24 * You should have received a copy of the GNU General Public
25 * License along with this program; if not, write to the
26 * Free Software Foundation, Inc., 59 Temple Place,
27 * Suite 330, Boston, MA 02111-1307 USA
28 *
29 */
30
31#include <linux/kernel.h>
32#include <linux/gfp.h>
33#include <linux/module.h>
34#include <linux/init.h>
35#include <linux/proc_fs.h>
36#include <linux/seq_file.h>
37#include <asm/console.h>
38#include <asm/uaccess.h>
39#include <asm/machvec.h>
40
41#define BASE_DIR "srm_environment" /* Subdir in /proc/ */
42#define NAMED_DIR "named_variables" /* Subdir for known variables */
43#define NUMBERED_DIR "numbered_variables" /* Subdir for all variables */
44#define VERSION "0.0.6" /* Module version */
45#define NAME "srm_env" /* Module name */
46
47MODULE_AUTHOR("Jan-Benedict Glaw <jbglaw@lug-owl.de>");
48MODULE_DESCRIPTION("Accessing Alpha SRM environment through procfs interface");
49MODULE_LICENSE("GPL");
50
51typedef struct _srm_env {
52 char *name;
53 unsigned long id;
54 struct proc_dir_entry *proc_entry;
55} srm_env_t;
56
57static struct proc_dir_entry *base_dir;
58static struct proc_dir_entry *named_dir;
59static struct proc_dir_entry *numbered_dir;
60static char number[256][4];
61
62static srm_env_t srm_named_entries[] = {
63 { "auto_action", ENV_AUTO_ACTION },
64 { "boot_dev", ENV_BOOT_DEV },
65 { "bootdef_dev", ENV_BOOTDEF_DEV },
66 { "booted_dev", ENV_BOOTED_DEV },
67 { "boot_file", ENV_BOOT_FILE },
68 { "booted_file", ENV_BOOTED_FILE },
69 { "boot_osflags", ENV_BOOT_OSFLAGS },
70 { "booted_osflags", ENV_BOOTED_OSFLAGS },
71 { "boot_reset", ENV_BOOT_RESET },
72 { "dump_dev", ENV_DUMP_DEV },
73 { "enable_audit", ENV_ENABLE_AUDIT },
74 { "license", ENV_LICENSE },
75 { "char_set", ENV_CHAR_SET },
76 { "language", ENV_LANGUAGE },
77 { "tty_dev", ENV_TTY_DEV },
78 { NULL, 0 },
79};
80static srm_env_t srm_numbered_entries[256];
81
82
83static int srm_env_proc_show(struct seq_file *m, void *v)
84{
85 unsigned long ret;
86 srm_env_t *entry;
87 char *page;
88
89 entry = m->private;
90 page = (char *)__get_free_page(GFP_USER);
91 if (!page)
92 return -ENOMEM;
93
94 ret = callback_getenv(entry->id, page, PAGE_SIZE);
95
96 if ((ret >> 61) == 0) {
97 seq_write(m, page, ret);
98 ret = 0;
99 } else
100 ret = -EFAULT;
101 free_page((unsigned long)page);
102 return ret;
103}
104
105static int srm_env_proc_open(struct inode *inode, struct file *file)
106{
107 return single_open(file, srm_env_proc_show, PDE(inode)->data);
108}
109
110static ssize_t srm_env_proc_write(struct file *file, const char __user *buffer,
111 size_t count, loff_t *pos)
112{
113 int res;
114 srm_env_t *entry = PDE(file->f_path.dentry->d_inode)->data;
115 char *buf = (char *) __get_free_page(GFP_USER);
116 unsigned long ret1, ret2;
117
118 if (!buf)
119 return -ENOMEM;
120
121 res = -EINVAL;
122 if (count >= PAGE_SIZE)
123 goto out;
124
125 res = -EFAULT;
126 if (copy_from_user(buf, buffer, count))
127 goto out;
128 buf[count] = '\0';
129
130 ret1 = callback_setenv(entry->id, buf, count);
131 if ((ret1 >> 61) == 0) {
132 do
133 ret2 = callback_save_env();
134 while((ret2 >> 61) == 1);
135 res = (int) ret1;
136 }
137
138 out:
139 free_page((unsigned long)buf);
140 return res;
141}
142
143static const struct file_operations srm_env_proc_fops = {
144 .owner = THIS_MODULE,
145 .open = srm_env_proc_open,
146 .read = seq_read,
147 .llseek = seq_lseek,
148 .release = single_release,
149 .write = srm_env_proc_write,
150};
151
152static void
153srm_env_cleanup(void)
154{
155 srm_env_t *entry;
156 unsigned long var_num;
157
158 if (base_dir) {
159 /*
160 * Remove named entries
161 */
162 if (named_dir) {
163 entry = srm_named_entries;
164 while (entry->name != NULL && entry->id != 0) {
165 if (entry->proc_entry) {
166 remove_proc_entry(entry->name,
167 named_dir);
168 entry->proc_entry = NULL;
169 }
170 entry++;
171 }
172 remove_proc_entry(NAMED_DIR, base_dir);
173 }
174
175 /*
176 * Remove numbered entries
177 */
178 if (numbered_dir) {
179 for (var_num = 0; var_num <= 255; var_num++) {
180 entry = &srm_numbered_entries[var_num];
181
182 if (entry->proc_entry) {
183 remove_proc_entry(entry->name,
184 numbered_dir);
185 entry->proc_entry = NULL;
186 entry->name = NULL;
187 }
188 }
189 remove_proc_entry(NUMBERED_DIR, base_dir);
190 }
191
192 remove_proc_entry(BASE_DIR, NULL);
193 }
194
195 return;
196}
197
198static int __init
199srm_env_init(void)
200{
201 srm_env_t *entry;
202 unsigned long var_num;
203
204 /*
205 * Check system
206 */
207 if (!alpha_using_srm) {
208 printk(KERN_INFO "%s: This Alpha system doesn't "
209 "know about SRM (or you've booted "
210 "SRM->MILO->Linux, which gets "
211 "misdetected)...\n", __func__);
212 return -ENODEV;
213 }
214
215 /*
216 * Init numbers
217 */
218 for (var_num = 0; var_num <= 255; var_num++)
219 sprintf(number[var_num], "%ld", var_num);
220
221 /*
222 * Create base directory
223 */
224 base_dir = proc_mkdir(BASE_DIR, NULL);
225 if (!base_dir) {
226 printk(KERN_ERR "Couldn't create base dir /proc/%s\n",
227 BASE_DIR);
228 goto cleanup;
229 }
230
231 /*
232 * Create per-name subdirectory
233 */
234 named_dir = proc_mkdir(NAMED_DIR, base_dir);
235 if (!named_dir) {
236 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",
237 BASE_DIR, NAMED_DIR);
238 goto cleanup;
239 }
240
241 /*
242 * Create per-number subdirectory
243 */
244 numbered_dir = proc_mkdir(NUMBERED_DIR, base_dir);
245 if (!numbered_dir) {
246 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",
247 BASE_DIR, NUMBERED_DIR);
248 goto cleanup;
249
250 }
251
252 /*
253 * Create all named nodes
254 */
255 entry = srm_named_entries;
256 while (entry->name && entry->id) {
257 entry->proc_entry = proc_create_data(entry->name, 0644, named_dir,
258 &srm_env_proc_fops, entry);
259 if (!entry->proc_entry)
260 goto cleanup;
261 entry++;
262 }
263
264 /*
265 * Create all numbered nodes
266 */
267 for (var_num = 0; var_num <= 255; var_num++) {
268 entry = &srm_numbered_entries[var_num];
269 entry->name = number[var_num];
270
271 entry->proc_entry = proc_create_data(entry->name, 0644, numbered_dir,
272 &srm_env_proc_fops, entry);
273 if (!entry->proc_entry)
274 goto cleanup;
275
276 entry->id = var_num;
277 }
278
279 printk(KERN_INFO "%s: version %s loaded successfully\n", NAME,
280 VERSION);
281
282 return 0;
283
284cleanup:
285 srm_env_cleanup();
286
287 return -ENOMEM;
288}
289
290static void __exit
291srm_env_exit(void)
292{
293 srm_env_cleanup();
294 printk(KERN_INFO "%s: unloaded successfully\n", NAME);
295
296 return;
297}
298
299module_init(srm_env_init);
300module_exit(srm_env_exit);