| /* |
| * Originally from efivars.c |
| * |
| * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com> |
| * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com> |
| * |
| * 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 |
| */ |
| |
| #include <linux/capability.h> |
| #include <linux/types.h> |
| #include <linux/errno.h> |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/string.h> |
| #include <linux/smp.h> |
| #include <linux/efi.h> |
| #include <linux/sysfs.h> |
| #include <linux/device.h> |
| #include <linux/slab.h> |
| #include <linux/ctype.h> |
| #include <linux/ucs2_string.h> |
| |
| /* Private pointer to registered efivars */ |
| static struct efivars *__efivars; |
| |
| static bool efivar_wq_enabled = true; |
| DECLARE_WORK(efivar_work, NULL); |
| EXPORT_SYMBOL_GPL(efivar_work); |
| |
| static bool |
| validate_device_path(efi_char16_t *var_name, int match, u8 *buffer, |
| unsigned long len) |
| { |
| struct efi_generic_dev_path *node; |
| int offset = 0; |
| |
| node = (struct efi_generic_dev_path *)buffer; |
| |
| if (len < sizeof(*node)) |
| return false; |
| |
| while (offset <= len - sizeof(*node) && |
| node->length >= sizeof(*node) && |
| node->length <= len - offset) { |
| offset += node->length; |
| |
| if ((node->type == EFI_DEV_END_PATH || |
| node->type == EFI_DEV_END_PATH2) && |
| node->sub_type == EFI_DEV_END_ENTIRE) |
| return true; |
| |
| node = (struct efi_generic_dev_path *)(buffer + offset); |
| } |
| |
| /* |
| * If we're here then either node->length pointed past the end |
| * of the buffer or we reached the end of the buffer without |
| * finding a device path end node. |
| */ |
| return false; |
| } |
| |
| static bool |
| validate_boot_order(efi_char16_t *var_name, int match, u8 *buffer, |
| unsigned long len) |
| { |
| /* An array of 16-bit integers */ |
| if ((len % 2) != 0) |
| return false; |
| |
| return true; |
| } |
| |
| static bool |
| validate_load_option(efi_char16_t *var_name, int match, u8 *buffer, |
| unsigned long len) |
| { |
| u16 filepathlength; |
| int i, desclength = 0, namelen; |
| |
| namelen = ucs2_strnlen(var_name, EFI_VAR_NAME_LEN); |
| |
| /* Either "Boot" or "Driver" followed by four digits of hex */ |
| for (i = match; i < match+4; i++) { |
| if (var_name[i] > 127 || |
| hex_to_bin(var_name[i] & 0xff) < 0) |
| return true; |
| } |
| |
| /* Reject it if there's 4 digits of hex and then further content */ |
| if (namelen > match + 4) |
| return false; |
| |
| /* A valid entry must be at least 8 bytes */ |
| if (len < 8) |
| return false; |
| |
| filepathlength = buffer[4] | buffer[5] << 8; |
| |
| /* |
| * There's no stored length for the description, so it has to be |
| * found by hand |
| */ |
| desclength = ucs2_strsize((efi_char16_t *)(buffer + 6), len - 6) + 2; |
| |
| /* Each boot entry must have a descriptor */ |
| if (!desclength) |
| return false; |
| |
| /* |
| * If the sum of the length of the description, the claimed filepath |
| * length and the original header are greater than the length of the |
| * variable, it's malformed |
| */ |
| if ((desclength + filepathlength + 6) > len) |
| return false; |
| |
| /* |
| * And, finally, check the filepath |
| */ |
| return validate_device_path(var_name, match, buffer + desclength + 6, |
| filepathlength); |
| } |
| |
| static bool |
| validate_uint16(efi_char16_t *var_name, int match, u8 *buffer, |
| unsigned long len) |
| { |
| /* A single 16-bit integer */ |
| if (len != 2) |
| return false; |
| |
| return true; |
| } |
| |
| static bool |
| validate_ascii_string(efi_char16_t *var_name, int match, u8 *buffer, |
| unsigned long len) |
| { |
| int i; |
| |
| for (i = 0; i < len; i++) { |
| if (buffer[i] > 127) |
| return false; |
| |
| if (buffer[i] == 0) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| struct variable_validate { |
| efi_guid_t vendor; |
| char *name; |
| bool (*validate)(efi_char16_t *var_name, int match, u8 *data, |
| unsigned long len); |
| }; |
| |
| /* |
| * This is the list of variables we need to validate, as well as the |
| * whitelist for what we think is safe not to default to immutable. |
| * |
| * If it has a validate() method that's not NULL, it'll go into the |
| * validation routine. If not, it is assumed valid, but still used for |
| * whitelisting. |
| * |
| * Note that it's sorted by {vendor,name}, but globbed names must come after |
| * any other name with the same prefix. |
| */ |
| static const struct variable_validate variable_validate[] = { |
| { EFI_GLOBAL_VARIABLE_GUID, "BootNext", validate_uint16 }, |
| { EFI_GLOBAL_VARIABLE_GUID, "BootOrder", validate_boot_order }, |
| { EFI_GLOBAL_VARIABLE_GUID, "Boot*", validate_load_option }, |
| { EFI_GLOBAL_VARIABLE_GUID, "DriverOrder", validate_boot_order }, |
| { EFI_GLOBAL_VARIABLE_GUID, "Driver*", validate_load_option }, |
| { EFI_GLOBAL_VARIABLE_GUID, "ConIn", validate_device_path }, |
| { EFI_GLOBAL_VARIABLE_GUID, "ConInDev", validate_device_path }, |
| { EFI_GLOBAL_VARIABLE_GUID, "ConOut", validate_device_path }, |
| { EFI_GLOBAL_VARIABLE_GUID, "ConOutDev", validate_device_path }, |
| { EFI_GLOBAL_VARIABLE_GUID, "ErrOut", validate_device_path }, |
| { EFI_GLOBAL_VARIABLE_GUID, "ErrOutDev", validate_device_path }, |
| { EFI_GLOBAL_VARIABLE_GUID, "Lang", validate_ascii_string }, |
| { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL }, |
| { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string }, |
| { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 }, |
| { LINUX_EFI_CRASH_GUID, "*", NULL }, |
| { NULL_GUID, "", NULL }, |
| }; |
| |
| /* |
| * Check if @var_name matches the pattern given in @match_name. |
| * |
| * @var_name: an array of @len non-NUL characters. |
| * @match_name: a NUL-terminated pattern string, optionally ending in "*". A |
| * final "*" character matches any trailing characters @var_name, |
| * including the case when there are none left in @var_name. |
| * @match: on output, the number of non-wildcard characters in @match_name |
| * that @var_name matches, regardless of the return value. |
| * @return: whether @var_name fully matches @match_name. |
| */ |
| static bool |
| variable_matches(const char *var_name, size_t len, const char *match_name, |
| int *match) |
| { |
| for (*match = 0; ; (*match)++) { |
| char c = match_name[*match]; |
| |
| switch (c) { |
| case '*': |
| /* Wildcard in @match_name means we've matched. */ |
| return true; |
| |
| case '\0': |
| /* @match_name has ended. Has @var_name too? */ |
| return (*match == len); |
| |
| default: |
| /* |
| * We've reached a non-wildcard char in @match_name. |
| * Continue only if there's an identical character in |
| * @var_name. |
| */ |
| if (*match < len && c == var_name[*match]) |
| continue; |
| return false; |
| } |
| } |
| } |
| |
| bool |
| efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data, |
| unsigned long data_size) |
| { |
| int i; |
| unsigned long utf8_size; |
| u8 *utf8_name; |
| |
| utf8_size = ucs2_utf8size(var_name); |
| utf8_name = kmalloc(utf8_size + 1, GFP_KERNEL); |
| if (!utf8_name) |
| return false; |
| |
| ucs2_as_utf8(utf8_name, var_name, utf8_size); |
| utf8_name[utf8_size] = '\0'; |
| |
| for (i = 0; variable_validate[i].name[0] != '\0'; i++) { |
| const char *name = variable_validate[i].name; |
| int match = 0; |
| |
| if (efi_guidcmp(vendor, variable_validate[i].vendor)) |
| continue; |
| |
| if (variable_matches(utf8_name, utf8_size+1, name, &match)) { |
| if (variable_validate[i].validate == NULL) |
| break; |
| kfree(utf8_name); |
| return variable_validate[i].validate(var_name, match, |
| data, data_size); |
| } |
| } |
| kfree(utf8_name); |
| return true; |
| } |
| EXPORT_SYMBOL_GPL(efivar_validate); |
| |
| bool |
| efivar_variable_is_removable(efi_guid_t vendor, const char *var_name, |
| size_t len) |
| { |
| int i; |
| bool found = false; |
| int match = 0; |
| |
| /* |
| * Check if our variable is in the validated variables list |
| */ |
| for (i = 0; variable_validate[i].name[0] != '\0'; i++) { |
| if (efi_guidcmp(variable_validate[i].vendor, vendor)) |
| continue; |
| |
| if (variable_matches(var_name, len, |
| variable_validate[i].name, &match)) { |
| found = true; |
| break; |
| } |
| } |
| |
| /* |
| * If it's in our list, it is removable. |
| */ |
| return found; |
| } |
| EXPORT_SYMBOL_GPL(efivar_variable_is_removable); |
| |
| static efi_status_t |
| check_var_size(u32 attributes, unsigned long size) |
| { |
| const struct efivar_operations *fops = __efivars->ops; |
| |
| if (!fops->query_variable_store) |
| return EFI_UNSUPPORTED; |
| |
| return fops->query_variable_store(attributes, size); |
| } |
| |
| static int efi_status_to_err(efi_status_t status) |
| { |
| int err; |
| |
| switch (status) { |
| case EFI_SUCCESS: |
| err = 0; |
| break; |
| case EFI_INVALID_PARAMETER: |
| err = -EINVAL; |
| break; |
| case EFI_OUT_OF_RESOURCES: |
| err = -ENOSPC; |
| break; |
| case EFI_DEVICE_ERROR: |
| err = -EIO; |
| break; |
| case EFI_WRITE_PROTECTED: |
| err = -EROFS; |
| break; |
| case EFI_SECURITY_VIOLATION: |
| err = -EACCES; |
| break; |
| case EFI_NOT_FOUND: |
| err = -ENOENT; |
| break; |
| default: |
| err = -EINVAL; |
| } |
| |
| return err; |
| } |
| |
| static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor, |
| struct list_head *head) |
| { |
| struct efivar_entry *entry, *n; |
| unsigned long strsize1, strsize2; |
| bool found = false; |
| |
| strsize1 = ucs2_strsize(variable_name, 1024); |
| list_for_each_entry_safe(entry, n, head, list) { |
| strsize2 = ucs2_strsize(entry->var.VariableName, 1024); |
| if (strsize1 == strsize2 && |
| !memcmp(variable_name, &(entry->var.VariableName), |
| strsize2) && |
| !efi_guidcmp(entry->var.VendorGuid, |
| *vendor)) { |
| found = true; |
| break; |
| } |
| } |
| return found; |
| } |
| |
| /* |
| * Returns the size of variable_name, in bytes, including the |
| * terminating NULL character, or variable_name_size if no NULL |
| * character is found among the first variable_name_size bytes. |
| */ |
| static unsigned long var_name_strnsize(efi_char16_t *variable_name, |
| unsigned long variable_name_size) |
| { |
| unsigned long len; |
| efi_char16_t c; |
| |
| /* |
| * The variable name is, by definition, a NULL-terminated |
| * string, so make absolutely sure that variable_name_size is |
| * the value we expect it to be. If not, return the real size. |
| */ |
| for (len = 2; len <= variable_name_size; len += sizeof(c)) { |
| c = variable_name[(len / sizeof(c)) - 1]; |
| if (!c) |
| break; |
| } |
| |
| return min(len, variable_name_size); |
| } |
| |
| /* |
| * Print a warning when duplicate EFI variables are encountered and |
| * disable the sysfs workqueue since the firmware is buggy. |
| */ |
| static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid, |
| unsigned long len16) |
| { |
| size_t i, len8 = len16 / sizeof(efi_char16_t); |
| char *str8; |
| |
| /* |
| * Disable the workqueue since the algorithm it uses for |
| * detecting new variables won't work with this buggy |
| * implementation of GetNextVariableName(). |
| */ |
| efivar_wq_enabled = false; |
| |
| str8 = kzalloc(len8, GFP_KERNEL); |
| if (!str8) |
| return; |
| |
| for (i = 0; i < len8; i++) |
| str8[i] = str16[i]; |
| |
| printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n", |
| str8, vendor_guid); |
| kfree(str8); |
| } |
| |
| /** |
| * efivar_init - build the initial list of EFI variables |
| * @func: callback function to invoke for every variable |
| * @data: function-specific data to pass to @func |
| * @atomic: do we need to execute the @func-loop atomically? |
| * @duplicates: error if we encounter duplicates on @head? |
| * @head: initialised head of variable list |
| * |
| * Get every EFI variable from the firmware and invoke @func. @func |
| * should call efivar_entry_add() to build the list of variables. |
| * |
| * Returns 0 on success, or a kernel error code on failure. |
| */ |
| int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), |
| void *data, bool atomic, bool duplicates, |
| struct list_head *head) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| unsigned long variable_name_size = 1024; |
| efi_char16_t *variable_name; |
| efi_status_t status; |
| efi_guid_t vendor_guid; |
| int err = 0; |
| |
| variable_name = kzalloc(variable_name_size, GFP_KERNEL); |
| if (!variable_name) { |
| printk(KERN_ERR "efivars: Memory allocation failed.\n"); |
| return -ENOMEM; |
| } |
| |
| spin_lock_irq(&__efivars->lock); |
| |
| /* |
| * Per EFI spec, the maximum storage allocated for both |
| * the variable name and variable data is 1024 bytes. |
| */ |
| |
| do { |
| variable_name_size = 1024; |
| |
| status = ops->get_next_variable(&variable_name_size, |
| variable_name, |
| &vendor_guid); |
| switch (status) { |
| case EFI_SUCCESS: |
| if (!atomic) |
| spin_unlock_irq(&__efivars->lock); |
| |
| variable_name_size = var_name_strnsize(variable_name, |
| variable_name_size); |
| |
| /* |
| * Some firmware implementations return the |
| * same variable name on multiple calls to |
| * get_next_variable(). Terminate the loop |
| * immediately as there is no guarantee that |
| * we'll ever see a different variable name, |
| * and may end up looping here forever. |
| */ |
| if (duplicates && |
| variable_is_present(variable_name, &vendor_guid, head)) { |
| dup_variable_bug(variable_name, &vendor_guid, |
| variable_name_size); |
| if (!atomic) |
| spin_lock_irq(&__efivars->lock); |
| |
| status = EFI_NOT_FOUND; |
| break; |
| } |
| |
| err = func(variable_name, vendor_guid, variable_name_size, data); |
| if (err) |
| status = EFI_NOT_FOUND; |
| |
| if (!atomic) |
| spin_lock_irq(&__efivars->lock); |
| |
| break; |
| case EFI_NOT_FOUND: |
| break; |
| default: |
| printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n", |
| status); |
| status = EFI_NOT_FOUND; |
| break; |
| } |
| |
| } while (status != EFI_NOT_FOUND); |
| |
| spin_unlock_irq(&__efivars->lock); |
| |
| kfree(variable_name); |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(efivar_init); |
| |
| /** |
| * efivar_entry_add - add entry to variable list |
| * @entry: entry to add to list |
| * @head: list head |
| */ |
| void efivar_entry_add(struct efivar_entry *entry, struct list_head *head) |
| { |
| spin_lock_irq(&__efivars->lock); |
| list_add(&entry->list, head); |
| spin_unlock_irq(&__efivars->lock); |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_add); |
| |
| /** |
| * efivar_entry_remove - remove entry from variable list |
| * @entry: entry to remove from list |
| */ |
| void efivar_entry_remove(struct efivar_entry *entry) |
| { |
| spin_lock_irq(&__efivars->lock); |
| list_del(&entry->list); |
| spin_unlock_irq(&__efivars->lock); |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_remove); |
| |
| /* |
| * efivar_entry_list_del_unlock - remove entry from variable list |
| * @entry: entry to remove |
| * |
| * Remove @entry from the variable list and release the list lock. |
| * |
| * NOTE: slightly weird locking semantics here - we expect to be |
| * called with the efivars lock already held, and we release it before |
| * returning. This is because this function is usually called after |
| * set_variable() while the lock is still held. |
| */ |
| static void efivar_entry_list_del_unlock(struct efivar_entry *entry) |
| { |
| lockdep_assert_held(&__efivars->lock); |
| |
| list_del(&entry->list); |
| spin_unlock_irq(&__efivars->lock); |
| } |
| |
| /** |
| * __efivar_entry_delete - delete an EFI variable |
| * @entry: entry containing EFI variable to delete |
| * |
| * Delete the variable from the firmware but leave @entry on the |
| * variable list. |
| * |
| * This function differs from efivar_entry_delete() because it does |
| * not remove @entry from the variable list. Also, it is safe to be |
| * called from within a efivar_entry_iter_begin() and |
| * efivar_entry_iter_end() region, unlike efivar_entry_delete(). |
| * |
| * Returns 0 on success, or a converted EFI status code if |
| * set_variable() fails. |
| */ |
| int __efivar_entry_delete(struct efivar_entry *entry) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| efi_status_t status; |
| |
| lockdep_assert_held(&__efivars->lock); |
| |
| status = ops->set_variable(entry->var.VariableName, |
| &entry->var.VendorGuid, |
| 0, 0, NULL); |
| |
| return efi_status_to_err(status); |
| } |
| EXPORT_SYMBOL_GPL(__efivar_entry_delete); |
| |
| /** |
| * efivar_entry_delete - delete variable and remove entry from list |
| * @entry: entry containing variable to delete |
| * |
| * Delete the variable from the firmware and remove @entry from the |
| * variable list. It is the caller's responsibility to free @entry |
| * once we return. |
| * |
| * Returns 0 on success, or a converted EFI status code if |
| * set_variable() fails. |
| */ |
| int efivar_entry_delete(struct efivar_entry *entry) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| efi_status_t status; |
| |
| spin_lock_irq(&__efivars->lock); |
| status = ops->set_variable(entry->var.VariableName, |
| &entry->var.VendorGuid, |
| 0, 0, NULL); |
| if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) { |
| spin_unlock_irq(&__efivars->lock); |
| return efi_status_to_err(status); |
| } |
| |
| efivar_entry_list_del_unlock(entry); |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_delete); |
| |
| /** |
| * efivar_entry_set - call set_variable() |
| * @entry: entry containing the EFI variable to write |
| * @attributes: variable attributes |
| * @size: size of @data buffer |
| * @data: buffer containing variable data |
| * @head: head of variable list |
| * |
| * Calls set_variable() for an EFI variable. If creating a new EFI |
| * variable, this function is usually followed by efivar_entry_add(). |
| * |
| * Before writing the variable, the remaining EFI variable storage |
| * space is checked to ensure there is enough room available. |
| * |
| * If @head is not NULL a lookup is performed to determine whether |
| * the entry is already on the list. |
| * |
| * Returns 0 on success, -EEXIST if a lookup is performed and the entry |
| * already exists on the list, or a converted EFI status code if |
| * set_variable() fails. |
| */ |
| int efivar_entry_set(struct efivar_entry *entry, u32 attributes, |
| unsigned long size, void *data, struct list_head *head) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| efi_status_t status; |
| efi_char16_t *name = entry->var.VariableName; |
| efi_guid_t vendor = entry->var.VendorGuid; |
| |
| spin_lock_irq(&__efivars->lock); |
| |
| if (head && efivar_entry_find(name, vendor, head, false)) { |
| spin_unlock_irq(&__efivars->lock); |
| return -EEXIST; |
| } |
| |
| status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
| if (status == EFI_SUCCESS || status == EFI_UNSUPPORTED) |
| status = ops->set_variable(name, &vendor, |
| attributes, size, data); |
| |
| spin_unlock_irq(&__efivars->lock); |
| |
| return efi_status_to_err(status); |
| |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_set); |
| |
| /* |
| * efivar_entry_set_nonblocking - call set_variable_nonblocking() |
| * |
| * This function is guaranteed to not block and is suitable for calling |
| * from crash/panic handlers. |
| * |
| * Crucially, this function will not block if it cannot acquire |
| * __efivars->lock. Instead, it returns -EBUSY. |
| */ |
| static int |
| efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor, |
| u32 attributes, unsigned long size, void *data) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| unsigned long flags; |
| efi_status_t status; |
| |
| if (!spin_trylock_irqsave(&__efivars->lock, flags)) |
| return -EBUSY; |
| |
| status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
| if (status != EFI_SUCCESS) { |
| spin_unlock_irqrestore(&__efivars->lock, flags); |
| return -ENOSPC; |
| } |
| |
| status = ops->set_variable_nonblocking(name, &vendor, attributes, |
| size, data); |
| |
| spin_unlock_irqrestore(&__efivars->lock, flags); |
| return efi_status_to_err(status); |
| } |
| |
| /** |
| * efivar_entry_set_safe - call set_variable() if enough space in firmware |
| * @name: buffer containing the variable name |
| * @vendor: variable vendor guid |
| * @attributes: variable attributes |
| * @block: can we block in this context? |
| * @size: size of @data buffer |
| * @data: buffer containing variable data |
| * |
| * Ensures there is enough free storage in the firmware for this variable, and |
| * if so, calls set_variable(). If creating a new EFI variable, this function |
| * is usually followed by efivar_entry_add(). |
| * |
| * Returns 0 on success, -ENOSPC if the firmware does not have enough |
| * space for set_variable() to succeed, or a converted EFI status code |
| * if set_variable() fails. |
| */ |
| int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes, |
| bool block, unsigned long size, void *data) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| unsigned long flags; |
| efi_status_t status; |
| |
| if (!ops->query_variable_store) |
| return -ENOSYS; |
| |
| /* |
| * If the EFI variable backend provides a non-blocking |
| * ->set_variable() operation and we're in a context where we |
| * cannot block, then we need to use it to avoid live-locks, |
| * since the implication is that the regular ->set_variable() |
| * will block. |
| * |
| * If no ->set_variable_nonblocking() is provided then |
| * ->set_variable() is assumed to be non-blocking. |
| */ |
| if (!block && ops->set_variable_nonblocking) |
| return efivar_entry_set_nonblocking(name, vendor, attributes, |
| size, data); |
| |
| if (!block) { |
| if (!spin_trylock_irqsave(&__efivars->lock, flags)) |
| return -EBUSY; |
| } else { |
| spin_lock_irqsave(&__efivars->lock, flags); |
| } |
| |
| status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); |
| if (status != EFI_SUCCESS) { |
| spin_unlock_irqrestore(&__efivars->lock, flags); |
| return -ENOSPC; |
| } |
| |
| status = ops->set_variable(name, &vendor, attributes, size, data); |
| |
| spin_unlock_irqrestore(&__efivars->lock, flags); |
| |
| return efi_status_to_err(status); |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_set_safe); |
| |
| /** |
| * efivar_entry_find - search for an entry |
| * @name: the EFI variable name |
| * @guid: the EFI variable vendor's guid |
| * @head: head of the variable list |
| * @remove: should we remove the entry from the list? |
| * |
| * Search for an entry on the variable list that has the EFI variable |
| * name @name and vendor guid @guid. If an entry is found on the list |
| * and @remove is true, the entry is removed from the list. |
| * |
| * The caller MUST call efivar_entry_iter_begin() and |
| * efivar_entry_iter_end() before and after the invocation of this |
| * function, respectively. |
| * |
| * Returns the entry if found on the list, %NULL otherwise. |
| */ |
| struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid, |
| struct list_head *head, bool remove) |
| { |
| struct efivar_entry *entry, *n; |
| int strsize1, strsize2; |
| bool found = false; |
| |
| lockdep_assert_held(&__efivars->lock); |
| |
| list_for_each_entry_safe(entry, n, head, list) { |
| strsize1 = ucs2_strsize(name, 1024); |
| strsize2 = ucs2_strsize(entry->var.VariableName, 1024); |
| if (strsize1 == strsize2 && |
| !memcmp(name, &(entry->var.VariableName), strsize1) && |
| !efi_guidcmp(guid, entry->var.VendorGuid)) { |
| found = true; |
| break; |
| } |
| } |
| |
| if (!found) |
| return NULL; |
| |
| if (remove) { |
| if (entry->scanning) { |
| /* |
| * The entry will be deleted |
| * after scanning is completed. |
| */ |
| entry->deleting = true; |
| } else |
| list_del(&entry->list); |
| } |
| |
| return entry; |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_find); |
| |
| /** |
| * efivar_entry_size - obtain the size of a variable |
| * @entry: entry for this variable |
| * @size: location to store the variable's size |
| */ |
| int efivar_entry_size(struct efivar_entry *entry, unsigned long *size) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| efi_status_t status; |
| |
| *size = 0; |
| |
| spin_lock_irq(&__efivars->lock); |
| status = ops->get_variable(entry->var.VariableName, |
| &entry->var.VendorGuid, NULL, size, NULL); |
| spin_unlock_irq(&__efivars->lock); |
| |
| if (status != EFI_BUFFER_TOO_SMALL) |
| return efi_status_to_err(status); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_size); |
| |
| /** |
| * __efivar_entry_get - call get_variable() |
| * @entry: read data for this variable |
| * @attributes: variable attributes |
| * @size: size of @data buffer |
| * @data: buffer to store variable data |
| * |
| * The caller MUST call efivar_entry_iter_begin() and |
| * efivar_entry_iter_end() before and after the invocation of this |
| * function, respectively. |
| */ |
| int __efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
| unsigned long *size, void *data) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| efi_status_t status; |
| |
| lockdep_assert_held(&__efivars->lock); |
| |
| status = ops->get_variable(entry->var.VariableName, |
| &entry->var.VendorGuid, |
| attributes, size, data); |
| |
| return efi_status_to_err(status); |
| } |
| EXPORT_SYMBOL_GPL(__efivar_entry_get); |
| |
| /** |
| * efivar_entry_get - call get_variable() |
| * @entry: read data for this variable |
| * @attributes: variable attributes |
| * @size: size of @data buffer |
| * @data: buffer to store variable data |
| */ |
| int efivar_entry_get(struct efivar_entry *entry, u32 *attributes, |
| unsigned long *size, void *data) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| efi_status_t status; |
| |
| spin_lock_irq(&__efivars->lock); |
| status = ops->get_variable(entry->var.VariableName, |
| &entry->var.VendorGuid, |
| attributes, size, data); |
| spin_unlock_irq(&__efivars->lock); |
| |
| return efi_status_to_err(status); |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_get); |
| |
| /** |
| * efivar_entry_set_get_size - call set_variable() and get new size (atomic) |
| * @entry: entry containing variable to set and get |
| * @attributes: attributes of variable to be written |
| * @size: size of data buffer |
| * @data: buffer containing data to write |
| * @set: did the set_variable() call succeed? |
| * |
| * This is a pretty special (complex) function. See efivarfs_file_write(). |
| * |
| * Atomically call set_variable() for @entry and if the call is |
| * successful, return the new size of the variable from get_variable() |
| * in @size. The success of set_variable() is indicated by @set. |
| * |
| * Returns 0 on success, -EINVAL if the variable data is invalid, |
| * -ENOSPC if the firmware does not have enough available space, or a |
| * converted EFI status code if either of set_variable() or |
| * get_variable() fail. |
| * |
| * If the EFI variable does not exist when calling set_variable() |
| * (EFI_NOT_FOUND), @entry is removed from the variable list. |
| */ |
| int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes, |
| unsigned long *size, void *data, bool *set) |
| { |
| const struct efivar_operations *ops = __efivars->ops; |
| efi_char16_t *name = entry->var.VariableName; |
| efi_guid_t *vendor = &entry->var.VendorGuid; |
| efi_status_t status; |
| int err; |
| |
| *set = false; |
| |
| if (efivar_validate(*vendor, name, data, *size) == false) |
| return -EINVAL; |
| |
| /* |
| * The lock here protects the get_variable call, the conditional |
| * set_variable call, and removal of the variable from the efivars |
| * list (in the case of an authenticated delete). |
| */ |
| spin_lock_irq(&__efivars->lock); |
| |
| /* |
| * Ensure that the available space hasn't shrunk below the safe level |
| */ |
| status = check_var_size(attributes, *size + ucs2_strsize(name, 1024)); |
| if (status != EFI_SUCCESS) { |
| if (status != EFI_UNSUPPORTED) { |
| err = efi_status_to_err(status); |
| goto out; |
| } |
| |
| if (*size > 65536) { |
| err = -ENOSPC; |
| goto out; |
| } |
| } |
| |
| status = ops->set_variable(name, vendor, attributes, *size, data); |
| if (status != EFI_SUCCESS) { |
| err = efi_status_to_err(status); |
| goto out; |
| } |
| |
| *set = true; |
| |
| /* |
| * Writing to the variable may have caused a change in size (which |
| * could either be an append or an overwrite), or the variable to be |
| * deleted. Perform a GetVariable() so we can tell what actually |
| * happened. |
| */ |
| *size = 0; |
| status = ops->get_variable(entry->var.VariableName, |
| &entry->var.VendorGuid, |
| NULL, size, NULL); |
| |
| if (status == EFI_NOT_FOUND) |
| efivar_entry_list_del_unlock(entry); |
| else |
| spin_unlock_irq(&__efivars->lock); |
| |
| if (status && status != EFI_BUFFER_TOO_SMALL) |
| return efi_status_to_err(status); |
| |
| return 0; |
| |
| out: |
| spin_unlock_irq(&__efivars->lock); |
| return err; |
| |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_set_get_size); |
| |
| /** |
| * efivar_entry_iter_begin - begin iterating the variable list |
| * |
| * Lock the variable list to prevent entry insertion and removal until |
| * efivar_entry_iter_end() is called. This function is usually used in |
| * conjunction with __efivar_entry_iter() or efivar_entry_iter(). |
| */ |
| void efivar_entry_iter_begin(void) |
| { |
| spin_lock_irq(&__efivars->lock); |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_iter_begin); |
| |
| /** |
| * efivar_entry_iter_end - finish iterating the variable list |
| * |
| * Unlock the variable list and allow modifications to the list again. |
| */ |
| void efivar_entry_iter_end(void) |
| { |
| spin_unlock_irq(&__efivars->lock); |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_iter_end); |
| |
| /** |
| * __efivar_entry_iter - iterate over variable list |
| * @func: callback function |
| * @head: head of the variable list |
| * @data: function-specific data to pass to callback |
| * @prev: entry to begin iterating from |
| * |
| * Iterate over the list of EFI variables and call @func with every |
| * entry on the list. It is safe for @func to remove entries in the |
| * list via efivar_entry_delete(). |
| * |
| * You MUST call efivar_enter_iter_begin() before this function, and |
| * efivar_entry_iter_end() afterwards. |
| * |
| * It is possible to begin iteration from an arbitrary entry within |
| * the list by passing @prev. @prev is updated on return to point to |
| * the last entry passed to @func. To begin iterating from the |
| * beginning of the list @prev must be %NULL. |
| * |
| * The restrictions for @func are the same as documented for |
| * efivar_entry_iter(). |
| */ |
| int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *), |
| struct list_head *head, void *data, |
| struct efivar_entry **prev) |
| { |
| struct efivar_entry *entry, *n; |
| int err = 0; |
| |
| if (!prev || !*prev) { |
| list_for_each_entry_safe(entry, n, head, list) { |
| err = func(entry, data); |
| if (err) |
| break; |
| } |
| |
| if (prev) |
| *prev = entry; |
| |
| return err; |
| } |
| |
| |
| list_for_each_entry_safe_continue((*prev), n, head, list) { |
| err = func(*prev, data); |
| if (err) |
| break; |
| } |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(__efivar_entry_iter); |
| |
| /** |
| * efivar_entry_iter - iterate over variable list |
| * @func: callback function |
| * @head: head of variable list |
| * @data: function-specific data to pass to callback |
| * |
| * Iterate over the list of EFI variables and call @func with every |
| * entry on the list. It is safe for @func to remove entries in the |
| * list via efivar_entry_delete() while iterating. |
| * |
| * Some notes for the callback function: |
| * - a non-zero return value indicates an error and terminates the loop |
| * - @func is called from atomic context |
| */ |
| int efivar_entry_iter(int (*func)(struct efivar_entry *, void *), |
| struct list_head *head, void *data) |
| { |
| int err = 0; |
| |
| efivar_entry_iter_begin(); |
| err = __efivar_entry_iter(func, head, data, NULL); |
| efivar_entry_iter_end(); |
| |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(efivar_entry_iter); |
| |
| /** |
| * efivars_kobject - get the kobject for the registered efivars |
| * |
| * If efivars_register() has not been called we return NULL, |
| * otherwise return the kobject used at registration time. |
| */ |
| struct kobject *efivars_kobject(void) |
| { |
| if (!__efivars) |
| return NULL; |
| |
| return __efivars->kobject; |
| } |
| EXPORT_SYMBOL_GPL(efivars_kobject); |
| |
| /** |
| * efivar_run_worker - schedule the efivar worker thread |
| */ |
| void efivar_run_worker(void) |
| { |
| if (efivar_wq_enabled) |
| schedule_work(&efivar_work); |
| } |
| EXPORT_SYMBOL_GPL(efivar_run_worker); |
| |
| /** |
| * efivars_register - register an efivars |
| * @efivars: efivars to register |
| * @ops: efivars operations |
| * @kobject: @efivars-specific kobject |
| * |
| * Only a single efivars can be registered at any time. |
| */ |
| int efivars_register(struct efivars *efivars, |
| const struct efivar_operations *ops, |
| struct kobject *kobject) |
| { |
| spin_lock_init(&efivars->lock); |
| efivars->ops = ops; |
| efivars->kobject = kobject; |
| |
| __efivars = efivars; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(efivars_register); |
| |
| /** |
| * efivars_unregister - unregister an efivars |
| * @efivars: efivars to unregister |
| * |
| * The caller must have already removed every entry from the list, |
| * failure to do so is an error. |
| */ |
| int efivars_unregister(struct efivars *efivars) |
| { |
| int rv; |
| |
| if (!__efivars) { |
| printk(KERN_ERR "efivars not registered\n"); |
| rv = -EINVAL; |
| goto out; |
| } |
| |
| if (__efivars != efivars) { |
| rv = -EINVAL; |
| goto out; |
| } |
| |
| __efivars = NULL; |
| |
| rv = 0; |
| out: |
| return rv; |
| } |
| EXPORT_SYMBOL_GPL(efivars_unregister); |