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} srm_env_t;
55
56static struct proc_dir_entry	*base_dir;
57static struct proc_dir_entry	*named_dir;
58static struct proc_dir_entry	*numbered_dir;
59
60static 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
79static 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
100static 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
105static 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
138static 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
147static int __init
148srm_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
222cleanup:
223	remove_proc_subtree(BASE_DIR, NULL);
224	return -ENOMEM;
225}
226
227static void __exit
228srm_env_exit(void)
229{
230	remove_proc_subtree(BASE_DIR, NULL);
231	printk(KERN_INFO "%s: unloaded successfully\n", NAME);
232}
233
234module_init(srm_env_init);
235module_exit(srm_env_exit);
236