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 <linux/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
47 MODULE_AUTHOR("Jan-Benedict Glaw <jbglaw@lug-owl.de>");
48 MODULE_DESCRIPTION("Accessing Alpha SRM environment through procfs interface");
49 MODULE_LICENSE("GPL");
50
51 typedef struct _srm_env {
52 char *name;
53 unsigned long id;
54 } srm_env_t;
55
56 static struct proc_dir_entry *base_dir;
57 static struct proc_dir_entry *named_dir;
58 static struct proc_dir_entry *numbered_dir;
59
60 static srm_env_t srm_named_entries[] = {
61 { "auto_action", ENV_AUTO_ACTION },
62 { "boot_dev", ENV_BOOT_DEV },
63 { "bootdef_dev", ENV_BOOTDEF_DEV },
64 { "booted_dev", ENV_BOOTED_DEV },
65 { "boot_file", ENV_BOOT_FILE },
66 { "booted_file", ENV_BOOTED_FILE },
67 { "boot_osflags", ENV_BOOT_OSFLAGS },
68 { "booted_osflags", ENV_BOOTED_OSFLAGS },
69 { "boot_reset", ENV_BOOT_RESET },
70 { "dump_dev", ENV_DUMP_DEV },
71 { "enable_audit", ENV_ENABLE_AUDIT },
72 { "license", ENV_LICENSE },
73 { "char_set", ENV_CHAR_SET },
74 { "language", ENV_LANGUAGE },
75 { "tty_dev", ENV_TTY_DEV },
76 { NULL, 0 },
77 };
78
srm_env_proc_show(struct seq_file * m,void * v)79 static int srm_env_proc_show(struct seq_file *m, void *v)
80 {
81 unsigned long ret;
82 unsigned long id = (unsigned long)m->private;
83 char *page;
84
85 page = (char *)__get_free_page(GFP_USER);
86 if (!page)
87 return -ENOMEM;
88
89 ret = callback_getenv(id, page, PAGE_SIZE);
90
91 if ((ret >> 61) == 0) {
92 seq_write(m, page, ret);
93 ret = 0;
94 } else
95 ret = -EFAULT;
96 free_page((unsigned long)page);
97 return ret;
98 }
99
srm_env_proc_open(struct inode * inode,struct file * file)100 static int srm_env_proc_open(struct inode *inode, struct file *file)
101 {
102 return single_open(file, srm_env_proc_show, PDE_DATA(inode));
103 }
104
srm_env_proc_write(struct file * file,const char __user * buffer,size_t count,loff_t * pos)105 static ssize_t srm_env_proc_write(struct file *file, const char __user *buffer,
106 size_t count, loff_t *pos)
107 {
108 int res;
109 unsigned long id = (unsigned long)PDE_DATA(file_inode(file));
110 char *buf = (char *) __get_free_page(GFP_USER);
111 unsigned long ret1, ret2;
112
113 if (!buf)
114 return -ENOMEM;
115
116 res = -EINVAL;
117 if (count >= PAGE_SIZE)
118 goto out;
119
120 res = -EFAULT;
121 if (copy_from_user(buf, buffer, count))
122 goto out;
123 buf[count] = '\0';
124
125 ret1 = callback_setenv(id, buf, count);
126 if ((ret1 >> 61) == 0) {
127 do
128 ret2 = callback_save_env();
129 while((ret2 >> 61) == 1);
130 res = (int) ret1;
131 }
132
133 out:
134 free_page((unsigned long)buf);
135 return res;
136 }
137
138 static const struct file_operations srm_env_proc_fops = {
139 .owner = THIS_MODULE,
140 .open = srm_env_proc_open,
141 .read = seq_read,
142 .llseek = seq_lseek,
143 .release = single_release,
144 .write = srm_env_proc_write,
145 };
146
147 static int __init
srm_env_init(void)148 srm_env_init(void)
149 {
150 srm_env_t *entry;
151 unsigned long var_num;
152
153 /*
154 * Check system
155 */
156 if (!alpha_using_srm) {
157 printk(KERN_INFO "%s: This Alpha system doesn't "
158 "know about SRM (or you've booted "
159 "SRM->MILO->Linux, which gets "
160 "misdetected)...\n", __func__);
161 return -ENODEV;
162 }
163
164 /*
165 * Create base directory
166 */
167 base_dir = proc_mkdir(BASE_DIR, NULL);
168 if (!base_dir) {
169 printk(KERN_ERR "Couldn't create base dir /proc/%s\n",
170 BASE_DIR);
171 return -ENOMEM;
172 }
173
174 /*
175 * Create per-name subdirectory
176 */
177 named_dir = proc_mkdir(NAMED_DIR, base_dir);
178 if (!named_dir) {
179 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",
180 BASE_DIR, NAMED_DIR);
181 goto cleanup;
182 }
183
184 /*
185 * Create per-number subdirectory
186 */
187 numbered_dir = proc_mkdir(NUMBERED_DIR, base_dir);
188 if (!numbered_dir) {
189 printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",
190 BASE_DIR, NUMBERED_DIR);
191 goto cleanup;
192
193 }
194
195 /*
196 * Create all named nodes
197 */
198 entry = srm_named_entries;
199 while (entry->name && entry->id) {
200 if (!proc_create_data(entry->name, 0644, named_dir,
201 &srm_env_proc_fops, (void *)entry->id))
202 goto cleanup;
203 entry++;
204 }
205
206 /*
207 * Create all numbered nodes
208 */
209 for (var_num = 0; var_num <= 255; var_num++) {
210 char name[4];
211 sprintf(name, "%ld", var_num);
212 if (!proc_create_data(name, 0644, numbered_dir,
213 &srm_env_proc_fops, (void *)var_num))
214 goto cleanup;
215 }
216
217 printk(KERN_INFO "%s: version %s loaded successfully\n", NAME,
218 VERSION);
219
220 return 0;
221
222 cleanup:
223 remove_proc_subtree(BASE_DIR, NULL);
224 return -ENOMEM;
225 }
226
227 static void __exit
srm_env_exit(void)228 srm_env_exit(void)
229 {
230 remove_proc_subtree(BASE_DIR, NULL);
231 printk(KERN_INFO "%s: unloaded successfully\n", NAME);
232 }
233
234 module_init(srm_env_init);
235 module_exit(srm_env_exit);
236
