patch-2.4.4 linux/arch/ia64/kernel/efivars.c

• Lines: 434
• Date: Thu Apr 5 12:51:47 2001
• Orig file: v2.4.3/linux/arch/ia64/kernel/efivars.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.3/linux/arch/ia64/kernel/efivars.c linux/arch/ia64/kernel/efivars.c
@@ -0,0 +1,433 @@
+/*
+ * EFI Variables - efivars.c
+ *
+ * Copyright (C) 2001 Dell Computer Corporation <Matt_Domsch@dell.com>
+ *
+ * This code takes all variables accessible from EFI runtime and
+ *  exports them via /proc
+ *
+ * Reads to /proc/efi/varname return an efi_variable_t structure.
+ * Writes to /proc/efi/varname must be an efi_variable_t structure.
+ * Writes with DataSize = 0 or Attributes = 0 deletes the variable.
+ * Writes with a new value in VariableName+VendorGuid creates
+ * a new variable.
+ *
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Changelog:
+ *
+ *  12 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
+ *   Feedback received from Stephane Eranian incorporated.
+ *   efivar_write() checks copy_from_user() return value.
+ *   efivar_read/write() returns proper errno.
+ *   v0.02 release to linux-ia64@linuxia64.org
+ *
+ *  26 February 2001 - Matt Domsch <Matt_Domsch@dell.com>
+ *   v0.01 release to linux-ia64@linuxia64.org
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>		/* for capable() */
+#include <linux/mm.h>
+#include <linux/module.h>
+
+#include <asm/efi.h>
+#include <asm/uaccess.h>
+#ifdef CONFIG_SMP
+#include <linux/smp.h>
+#endif
+
+MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
+MODULE_DESCRIPTION("/proc interface to EFI Variables");
+
+#define EFIVARS_VERSION "0.02 2001-Mar-12"
+
+static int
+efivar_read(char *page, char **start, off_t off,
+	    int count, int *eof, void *data);
+static int
+efivar_write(struct file *file, const char *buffer,
+	     unsigned long count, void *data);
+
+
+/*
+ * The maximum size of VariableName + Data = 1024
+ * Therefore, it's reasonable to save that much
+ * space in each part of the structure,
+ * and we use a page for reading/writing.
+ */
+
+typedef struct _efi_variable_t {
+	efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
+	efi_guid_t    VendorGuid;
+	unsigned long DataSize;
+	__u8          Data[1024];
+	efi_status_t  Status;
+	__u32         Attributes;
+} __attribute__((packed)) efi_variable_t;
+
+
+typedef struct _efivar_entry_t {
+	efi_variable_t          var;
+	struct proc_dir_entry   *entry;
+	struct list_head        list;
+} efivar_entry_t;
+
+spinlock_t efivars_lock = SPIN_LOCK_UNLOCKED;
+static LIST_HEAD(efivar_list);
+static struct proc_dir_entry *efi_dir = NULL;
+
+#define efivar_entry(n) list_entry(n, efivar_entry_t, list)
+
+/* Return the number of unicode characters in data */
+static unsigned long
+utf8_strlen(efi_char16_t *data, unsigned long maxlength)
+{
+	unsigned long length = 0;
+	while (*data++ != 0 && length < maxlength)
+		length++;
+	return length;
+}
+
+/* Return the number of bytes is the length of this string */
+/* Note: this is NOT the same as the number of unicode characters */
+static inline unsigned long
+utf8_strsize(efi_char16_t *data, unsigned long maxlength)
+{
+	return utf8_strlen(data, maxlength/sizeof(efi_char16_t)) *
+		sizeof(efi_char16_t);
+}
+
+
+static int
+proc_calc_metrics(char *page, char **start, off_t off,
+		  int count, int *eof, int len)
+{
+	if (len <= off+count) *eof = 1;
+	*start = page + off;
+	len -= off;
+	if (len>count) len = count;
+	if (len<0) len = 0;
+	return len;
+}
+
+
+static void
+uuid_unparse(efi_guid_t *guid, char *out)
+{
+	sprintf(out, "%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+		guid->data1, guid->data2, guid->data3,
+		guid->data4[0], guid->data4[1], guid->data4[2], guid->data4[3],
+		guid->data4[4], guid->data4[5], guid->data4[6], guid->data4[7]);
+}
+
+
+
+
+
+/*
+ * efivar_create_proc_entry()
+ * Requires:
+ *    variable_name_size = number of bytes required to hold
+ *                         variable_name (not counting the NULL
+ *                         character at the end.
+ * Returns 1 on failure, 0 on success
+ */
+static int
+efivar_create_proc_entry(unsigned long variable_name_size,
+			 efi_char16_t *variable_name,
+			 efi_guid_t *vendor_guid)
+{
+
+	int i, short_name_size = variable_name_size /
+		sizeof(efi_char16_t) + 38;
+	char *short_name = kmalloc(short_name_size+1,
+				   GFP_KERNEL);
+	efivar_entry_t *new_efivar = kmalloc(sizeof(efivar_entry_t),
+					     GFP_KERNEL);
+	if (!short_name || !new_efivar)  {
+		if (short_name)        kfree(short_name);
+		if (new_efivar)        kfree(new_efivar);
+		return 1;
+	}
+	memset(short_name, 0, short_name_size+1);
+	memset(new_efivar, 0, sizeof(efivar_entry_t));
+
+	memcpy(new_efivar->var.VariableName, variable_name,
+	       variable_name_size);
+	memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
+
+	/* Convert Unicode to normal chars (assume top bits are 0),
+	   ala UTF-8 */
+	for (i=0; i<variable_name_size / sizeof(efi_char16_t); i++) {
+		short_name[i] = variable_name[i] & 0xFF;
+	}
+
+	/* This is ugly, but necessary to separate one vendor's
+	   private variables from another's.         */
+
+	*(short_name + strlen(short_name)) = '-';
+	uuid_unparse(vendor_guid, short_name + strlen(short_name));
+
+
+	/* Create the entry in proc */
+	new_efivar->entry = create_proc_entry(short_name, 0600, efi_dir);
+	kfree(short_name); short_name = NULL;
+	if (!new_efivar->entry) return 1;
+
+
+	new_efivar->entry->data = new_efivar;
+	new_efivar->entry->read_proc = efivar_read;
+	new_efivar->entry->write_proc = efivar_write;
+
+	list_add(&new_efivar->list, &efivar_list);
+
+
+	return 0;
+}
+
+
+
+/***********************************************************
+ * efivar_read()
+ * Requires:
+ * Modifies: page
+ * Returns: number of bytes written, or -EINVAL on failure
+ ***********************************************************/
+
+static int
+efivar_read(char *page, char **start, off_t off, int count, int *eof, void *data)
+{
+	int len = sizeof(efi_variable_t);
+	efivar_entry_t *efi_var = data;
+	efi_variable_t *var_data = (efi_variable_t *)page;
+
+	if (!page || !data) return -EINVAL;
+
+	spin_lock(&efivars_lock);
+	MOD_INC_USE_COUNT;
+
+	memcpy(var_data, &efi_var->var, len);
+
+	var_data->DataSize = 1024;
+	var_data->Status = efi.get_variable(var_data->VariableName,
+					    &var_data->VendorGuid,
+					    &var_data->Attributes,
+					    &var_data->DataSize,
+					    var_data->Data);
+
+	MOD_DEC_USE_COUNT;
+	spin_unlock(&efivars_lock);
+
+	return proc_calc_metrics(page, start, off, count, eof, len);
+}
+
+/***********************************************************
+ * efivar_write()
+ * Requires: data is an efi_setvariable_t data type,
+ *           properly filled in, possibly by a call
+ *           first to efivar_read().
+ *           Caller must have CAP_SYS_ADMIN
+ * Modifies: NVRAM
+ * Returns: var_data->DataSize on success, errno on failure
+ *
+ ***********************************************************/
+static int
+efivar_write(struct file *file, const char *buffer,
+	     unsigned long count, void *data)
+{
+	unsigned long strsize1, strsize2;
+	int found=0;
+	struct list_head *pos;
+	unsigned long size = sizeof(efi_variable_t);
+	efi_status_t status;
+	efivar_entry_t *efivar = data, *search_efivar = NULL;
+	efi_variable_t *var_data;
+	if (!data || count != size) {
+		printk(KERN_WARNING "efivars: improper struct of size 0x%lx passed.\n", count);
+		return -EINVAL;
+	}
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	spin_lock(&efivars_lock);
+	MOD_INC_USE_COUNT;
+
+	var_data = kmalloc(size, GFP_KERNEL);
+	if (!var_data) {
+		MOD_DEC_USE_COUNT;
+		spin_unlock(&efivars_lock);
+		return -ENOMEM;
+	}
+	if (copy_from_user(var_data, buffer, size)) {
+		MOD_DEC_USE_COUNT;
+		spin_unlock(&efivars_lock);
+		return -EFAULT;
+	}
+
+
+	/* Since the data ptr we've currently got is probably for
+	   a different variable find the right variable.
+	   This allows any properly formatted data structure to
+	   be written to any of the files in /proc/efi and it will work.
+	*/
+	list_for_each(pos, &efivar_list) {
+		search_efivar = efivar_entry(pos);
+		strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
+		strsize2 = utf8_strsize(var_data->VariableName, 1024);
+		if ( strsize1 == strsize2 &&
+		     !memcmp(&(search_efivar->var.VariableName),
+			     var_data->VariableName, strsize1) &&
+		     !efi_guidcmp(search_efivar->var.VendorGuid,
+				  var_data->VendorGuid)) {
+			found = 1;
+			break;
+		}
+	}
+	if (found) efivar = search_efivar;
+
+	status = efi.set_variable(var_data->VariableName,
+				  &var_data->VendorGuid,
+				  var_data->Attributes,
+				  var_data->DataSize,
+				  var_data->Data);
+
+	if (status != EFI_SUCCESS) {
+		printk(KERN_WARNING "set_variable() failed: status=%lx\n", status);
+		kfree(var_data);
+		MOD_DEC_USE_COUNT;
+		spin_unlock(&efivars_lock);
+		return -EIO;
+	}
+
+
+	if (!var_data->DataSize || !var_data->Attributes) {
+		/* We just deleted the NVRAM variable */
+		remove_proc_entry(efivar->entry->name, efi_dir);
+		list_del(&efivar->list);
+		kfree(efivar);
+	}
+
+	/* If this is a new variable, set up the proc entry for it. */
+	if (!found) {
+		efivar_create_proc_entry(utf8_strsize(var_data->VariableName,
+						      1024),
+					 var_data->VariableName,
+					 &var_data->VendorGuid);
+	}
+
+	kfree(var_data);
+	MOD_DEC_USE_COUNT;
+	spin_unlock(&efivars_lock);
+	return size;
+}
+
+
+
+static int __init
+efivars_init(void)
+{
+
+	efi_status_t status;
+	efi_guid_t vendor_guid;
+	efi_char16_t *variable_name = kmalloc(1024, GFP_KERNEL);
+	unsigned long variable_name_size = 1024;
+
+	spin_lock(&efivars_lock);
+
+	printk(KERN_INFO "EFI Variables Facility v%s\n", EFIVARS_VERSION);
+
+	/* Per EFI spec, the maximum storage allocated for both
+	   the variable name and variable data is 1024 bytes.
+	*/
+
+	efi_dir = proc_mkdir("efi", NULL);
+
+	memset(variable_name, 0, 1024);
+
+	do {
+		variable_name_size=1024;
+
+		status = efi.get_next_variable(&variable_name_size,
+					       variable_name,
+					       &vendor_guid);
+
+
+		switch (status) {
+		case EFI_SUCCESS:
+			efivar_create_proc_entry(variable_name_size,
+						 variable_name,
+						 &vendor_guid);
+			break;
+		case EFI_NOT_FOUND:
+			break;
+		default:
+			printk(KERN_WARNING "get_next_variable: status=%lx\n", status);
+			status = EFI_NOT_FOUND;
+			break;
+		}
+
+	} while (status != EFI_NOT_FOUND);
+
+	kfree(variable_name);
+	spin_unlock(&efivars_lock);
+	return 0;
+}
+
+static void __exit
+efivars_exit(void)
+{
+	struct list_head *pos;
+	efivar_entry_t *efivar;
+
+	spin_lock(&efivars_lock);
+
+	list_for_each(pos, &efivar_list) {
+		efivar = efivar_entry(pos);
+		remove_proc_entry(efivar->entry->name, efi_dir);
+		list_del(&efivar->list);
+		kfree(efivar);
+	}
+	remove_proc_entry(efi_dir->name, NULL);
+	spin_unlock(&efivars_lock);
+
+}
+
+module_init(efivars_init);
+module_exit(efivars_exit);
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-indent-level: 4
+ * c-brace-imaginary-offset: 0
+ * c-brace-offset: -4
+ * c-argdecl-indent: 4
+ * c-label-offset: -4
+ * c-continued-statement-offset: 4
+ * c-continued-brace-offset: 0
+ * indent-tabs-mode: nil
+ * tab-width: 8
+ * End:
+ */