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/*
* 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/vars/varname return an efi_variable_t structure.
* Writes to /proc/efi/vars/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:
*
* 20 April 2001 - Matt Domsch <Matt_Domsch@dell.com>
* Moved vars from /proc/efi to /proc/efi/vars, and made
* efi.c own the /proc/efi directory.
* v0.03 release to linux-ia64@linuxia64.org
*
* 26 March 2001 - Matt Domsch <Matt_Domsch@dell.com>
* At the request of Stephane, moved ownership of /proc/efi
* to efi.c, and now efivars lives under /proc/efi/vars.
*
* 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");
MODULE_LICENSE("GPL");
#define EFIVARS_VERSION "0.03 2001-Apr-20"
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;
static spinlock_t efivars_lock = SPIN_LOCK_UNLOCKED;
static LIST_HEAD(efivar_list);
static struct proc_dir_entry *efi_vars_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_vars_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;
MOD_INC_USE_COUNT;
var_data = kmalloc(size, GFP_KERNEL);
if (!var_data) {
MOD_DEC_USE_COUNT;
return -ENOMEM;
}
if (copy_from_user(var_data, buffer, size)) {
MOD_DEC_USE_COUNT;
kfree(var_data);
return -EFAULT;
}
spin_lock(&efivars_lock);
/* 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/vars 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_vars_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);
/* Since efi.c happens before procfs is available,
we create the directory here if it doesn't
already exist. There's probably a better way
to do this.
*/
if (!efi_dir)
efi_dir = proc_mkdir("efi", NULL);
efi_vars_dir = proc_mkdir("vars", efi_dir);
/* Per EFI spec, the maximum storage allocated for both
the variable name and variable data is 1024 bytes.
*/
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_vars_dir);
list_del(&efivar->list);
kfree(efivar);
}
remove_proc_entry(efi_vars_dir->name, efi_dir);
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:
*/
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