// SPDX-License-Identifier: GPL-2.0-only/* * srm_env.c - Access to SRM environment *             variables through linux' procfs * * (C) 2001,2002,2006 by Jan-Benedict Glaw <jbglaw@lug-owl.de> * * This driver is a modified version of Erik Mouw's example proc * interface, so: thank you, Erik! He can be reached via email at * <J.A.K.Mouw@its.tudelft.nl>. It is based on an idea * provided by DEC^WCompaq^WIntel's "Jumpstart" CD. They * included a patch like this as well. Thanks for idea! */ #include <linux/kernel.h>#include <linux/gfp.h>#include <linux/module.h>#include <linux/init.h>#include <linux/proc_fs.h>#include <linux/seq_file.h>#include <asm/console.h>#include <linux/uaccess.h>#include <asm/machvec.h> #define BASE_DIR	"srm_environment"	/* Subdir in /proc/		*/#define NAMED_DIR	"named_variables"	/* Subdir for known variables	*/#define NUMBERED_DIR	"numbered_variables"	/* Subdir for all variables	*/#define VERSION		"0.0.6"			/* Module version		*/#define NAME		"srm_env"		/* Module name			*/ MODULE_AUTHOR("Jan-Benedict Glaw <jbglaw@lug-owl.de>");MODULE_DESCRIPTION("Accessing Alpha SRM environment through procfs interface");MODULE_LICENSE("GPL"); typedef struct _srm_env {	char			*name;	unsigned long		id;} srm_env_t; static struct proc_dir_entry	*base_dir;static struct proc_dir_entry	*named_dir;static struct proc_dir_entry	*numbered_dir; static srm_env_t	srm_named_entries[] = {	{ "auto_action",	ENV_AUTO_ACTION		},	{ "boot_dev",		ENV_BOOT_DEV		},	{ "bootdef_dev",	ENV_BOOTDEF_DEV		},	{ "booted_dev",		ENV_BOOTED_DEV		},	{ "boot_file",		ENV_BOOT_FILE		},	{ "booted_file",	ENV_BOOTED_FILE		},	{ "boot_osflags",	ENV_BOOT_OSFLAGS	},	{ "booted_osflags",	ENV_BOOTED_OSFLAGS	},	{ "boot_reset",		ENV_BOOT_RESET		},	{ "dump_dev",		ENV_DUMP_DEV		},	{ "enable_audit",	ENV_ENABLE_AUDIT	},	{ "license",		ENV_LICENSE		},	{ "char_set",		ENV_CHAR_SET		},	{ "language",		ENV_LANGUAGE		},	{ "tty_dev",		ENV_TTY_DEV		},	{ NULL,			0			},}; static int srm_env_proc_show(struct seq_file *m, void *v){	unsigned long	ret;	unsigned long	id = (unsigned long)m->private;	char		*page; 	page = (char *)__get_free_page(GFP_USER);	if (!page)		return -ENOMEM; 	ret = callback_getenv(id, page, PAGE_SIZE); 	if ((ret >> 61) == 0) {		seq_write(m, page, ret);		ret = 0;	} else		ret = -EFAULT;	free_page((unsigned long)page);	return ret;} static int srm_env_proc_open(struct inode *inode, struct file *file){	return single_open(file, srm_env_proc_show, pde_data(inode));} static ssize_t srm_env_proc_write(struct file *file, const char __user *buffer,				  size_t count, loff_t *pos){	int res;	unsigned long	id = (unsigned long)pde_data(file_inode(file));	char		*buf = (char *) __get_free_page(GFP_USER);	unsigned long	ret1, ret2; 	if (!buf)		return -ENOMEM; 	res = -EINVAL;	if (count >= PAGE_SIZE)		goto out; 	res = -EFAULT;	if (copy_from_user(buf, buffer, count))		goto out;	buf[count] = '\0'; 	ret1 = callback_setenv(id, buf, count);	if ((ret1 >> 61) == 0) {		do			ret2 = callback_save_env();		while((ret2 >> 61) == 1);		res = (int) ret1;	}  out:	free_page((unsigned long)buf);	return res;} static const struct proc_ops srm_env_proc_ops = {	.proc_open	= srm_env_proc_open,	.proc_read	= seq_read,	.proc_lseek	= seq_lseek,	.proc_release	= single_release,	.proc_write	= srm_env_proc_write,}; static int __initsrm_env_init(void){	srm_env_t	*entry;	unsigned long	var_num; 	/*	 * Check system	 */	if (!alpha_using_srm) {		printk(KERN_INFO "%s: This Alpha system doesn't "				"know about SRM (or you've booted "				"SRM->MILO->Linux, which gets "				"misdetected)...\n", __func__);		return -ENODEV;	} 	/*	 * Create base directory	 */	base_dir = proc_mkdir(BASE_DIR, NULL);	if (!base_dir) {		printk(KERN_ERR "Couldn't create base dir /proc/%s\n",				BASE_DIR);		return -ENOMEM;	} 	/*	 * Create per-name subdirectory	 */	named_dir = proc_mkdir(NAMED_DIR, base_dir);	if (!named_dir) {		printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",				BASE_DIR, NAMED_DIR);		goto cleanup;	} 	/*	 * Create per-number subdirectory	 */	numbered_dir = proc_mkdir(NUMBERED_DIR, base_dir);	if (!numbered_dir) {		printk(KERN_ERR "Couldn't create dir /proc/%s/%s\n",				BASE_DIR, NUMBERED_DIR);		goto cleanup; 	} 	/*	 * Create all named nodes	 */	entry = srm_named_entries;	while (entry->name && entry->id) {		if (!proc_create_data(entry->name, 0644, named_dir,			     &srm_env_proc_ops, (void *)entry->id))			goto cleanup;		entry++;	} 	/*	 * Create all numbered nodes	 */	for (var_num = 0; var_num <= 255; var_num++) {		char name[4];		sprintf(name, "%ld", var_num);		if (!proc_create_data(name, 0644, numbered_dir,			     &srm_env_proc_ops, (void *)var_num))			goto cleanup;	} 	printk(KERN_INFO "%s: version %s loaded successfully\n", NAME,			VERSION); 	return 0; cleanup:	remove_proc_subtree(BASE_DIR, NULL);	return -ENOMEM;} static void __exitsrm_env_exit(void){	remove_proc_subtree(BASE_DIR, NULL);	printk(KERN_INFO "%s: unloaded successfully\n", NAME);} module_init(srm_env_init);module_exit(srm_env_exit);