/* * Originally from efivars.c * * Copyright (C) 2001,2003,2004 Dell * Copyright (C) 2004 Intel Corporation * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include /* Private pointer to registered efivars */ static struct efivars *__efivars; /* * efivars_lock protects three things: * 1) efivarfs_list and efivars_sysfs_list * 2) ->ops calls * 3) (un)registration of __efivars */ static DEFINE_SEMAPHORE(efivars_lock); 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; if (!__efivars) return EFI_UNSUPPORTED; fops = __efivars->ops; if (!fops->query_variable_store) return EFI_UNSUPPORTED; return fops->query_variable_store(attributes, size, false); } static efi_status_t check_var_size_nonblocking(u32 attributes, unsigned long size) { const struct efivar_operations *fops; if (!__efivars) return EFI_UNSUPPORTED; fops = __efivars->ops; if (!fops->query_variable_store) return EFI_UNSUPPORTED; return fops->query_variable_store(attributes, size, true); } 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 duplicates, struct list_head *head) { const struct efivar_operations *ops; unsigned long variable_name_size = 1024; efi_char16_t *variable_name; efi_status_t status; efi_guid_t vendor_guid; int err = 0; if (!__efivars) return -EFAULT; ops = __efivars->ops; variable_name = kzalloc(variable_name_size, GFP_KERNEL); if (!variable_name) { printk(KERN_ERR "efivars: Memory allocation failed.\n"); return -ENOMEM; } if (down_interruptible(&efivars_lock)) { err = -EINTR; goto free; } /* * 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 (duplicates) up(&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); status = EFI_NOT_FOUND; } else { err = func(variable_name, vendor_guid, variable_name_size, data); if (err) status = EFI_NOT_FOUND; } if (duplicates) { if (down_interruptible(&efivars_lock)) { err = -EINTR; goto free; } } 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); up(&efivars_lock); free: 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 * * Returns 0 on success, or a kernel error code on failure. */ int efivar_entry_add(struct efivar_entry *entry, struct list_head *head) { if (down_interruptible(&efivars_lock)) return -EINTR; list_add(&entry->list, head); up(&efivars_lock); return 0; } EXPORT_SYMBOL_GPL(efivar_entry_add); /** * efivar_entry_remove - remove entry from variable list * @entry: entry to remove from list * * Returns 0 on success, or a kernel error code on failure. */ int efivar_entry_remove(struct efivar_entry *entry) { if (down_interruptible(&efivars_lock)) return -EINTR; list_del(&entry->list); up(&efivars_lock); return 0; } 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) { list_del(&entry->list); up(&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) { efi_status_t status; if (!__efivars) return -EINVAL; status = __efivars->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, -EINTR if we can't grab the semaphore, * converted EFI status code if set_variable() fails. */ int efivar_entry_delete(struct efivar_entry *entry) { const struct efivar_operations *ops; efi_status_t status; if (down_interruptible(&efivars_lock)) return -EINTR; if (!__efivars) { up(&efivars_lock); return -EINVAL; } ops = __efivars->ops; status = ops->set_variable(entry->var.VariableName, &entry->var.VendorGuid, 0, 0, NULL); if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) { up(&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, -EINTR if we can't grab the semaphore, * -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; efi_status_t status; efi_char16_t *name = entry->var.VariableName; efi_guid_t vendor = entry->var.VendorGuid; if (down_interruptible(&efivars_lock)) return -EINTR; if (!__efivars) { up(&efivars_lock); return -EINVAL; } ops = __efivars->ops; if (head && efivar_entry_find(name, vendor, head, false)) { up(&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); up(&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; efi_status_t status; if (down_trylock(&efivars_lock)) return -EBUSY; if (!__efivars) { up(&efivars_lock); return -EINVAL; } status = check_var_size_nonblocking(attributes, size + ucs2_strsize(name, 1024)); if (status != EFI_SUCCESS) { up(&efivars_lock); return -ENOSPC; } ops = __efivars->ops; status = ops->set_variable_nonblocking(name, &vendor, attributes, size, data); up(&efivars_lock); 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; efi_status_t status; unsigned long varsize; if (!__efivars) return -EINVAL; ops = __efivars->ops; 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); varsize = size + ucs2_strsize(name, 1024); if (!block) { if (down_trylock(&efivars_lock)) return -EBUSY; status = check_var_size_nonblocking(attributes, varsize); } else { if (down_interruptible(&efivars_lock)) return -EINTR; status = check_var_size(attributes, varsize); } if (status != EFI_SUCCESS) { up(&efivars_lock); return -ENOSPC; } status = ops->set_variable(name, &vendor, attributes, size, data); up(&efivars_lock); 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; 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; efi_status_t status; *size = 0; if (down_interruptible(&efivars_lock)) return -EINTR; if (!__efivars) { up(&efivars_lock); return -EINVAL; } ops = __efivars->ops; status = ops->get_variable(entry->var.VariableName, &entry->var.VendorGuid, NULL, size, NULL); up(&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) { efi_status_t status; if (!__efivars) return -EINVAL; status = __efivars->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) { efi_status_t status; if (down_interruptible(&efivars_lock)) return -EINTR; if (!__efivars) { up(&efivars_lock); return -EINVAL; } status = __efivars->ops->get_variable(entry->var.VariableName, &entry->var.VendorGuid, attributes, size, data); up(&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; 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). */ if (down_interruptible(&efivars_lock)) return -EINTR; if (!__efivars) { err = -EINVAL; goto out; } /* * 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; } } ops = __efivars->ops; 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 up(&efivars_lock); if (status && status != EFI_BUFFER_TOO_SMALL) return efi_status_to_err(status); return 0; out: up(&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(). */ int efivar_entry_iter_begin(void) { return down_interruptible(&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) { up(&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; err = efivar_entry_iter_begin(); if (err) return err; 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) { if (down_interruptible(&efivars_lock)) return -EINTR; efivars->ops = ops; efivars->kobject = kobject; __efivars = efivars; pr_info("Registered efivars operations\n"); up(&efivars_lock); 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 (down_interruptible(&efivars_lock)) return -EINTR; if (!__efivars) { printk(KERN_ERR "efivars not registered\n"); rv = -EINVAL; goto out; } if (__efivars != efivars) { rv = -EINVAL; goto out; } pr_info("Unregistered efivars operations\n"); __efivars = NULL; rv = 0; out: up(&efivars_lock); return rv; } EXPORT_SYMBOL_GPL(efivars_unregister);