[PATCH v2 2/2] efi: Use sysfs_emit() not sprintf() to generate sysfs file contents

[Ard Biesheuvel <ardb+git@google.com>]

From: Ard Biesheuvel <ardb@kernel.org>

Use sysfs_emit() where appropriate to generate the contents of EFI
related sysfs nodes. This is a more robust wrapper around sprintf()
designed for this purpose.

Reported-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/x86/platform/efi/efi.c |  2 +-
 drivers/firmware/efi/efi.c  | 16 ++++++++--------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index d8fe93770c2a..5eb96c17883e 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -893,7 +893,7 @@ bool efi_is_table_address(unsigned long phys_addr)
 static ssize_t name##_show(struct kobject *kobj, \
 			   const struct kobj_attribute *attr, char *buf) \
 { \
-	return sprintf(buf, "0x%lx\n", EFI_FIELD(name)); \
+	return sysfs_emit(buf, "0x%lx\n", EFI_FIELD(name)); \
 }
 
 EFI_ATTR_SHOW(fw_vendor);
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 8026264d4990..b4504542cb2c 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -133,26 +133,26 @@ struct kobject *efi_kobj;
 static ssize_t systab_show(struct kobject *kobj,
 			   const struct kobj_attribute *attr, char *buf)
 {
-	char *str = buf;
+	int offset = 0;
 
 	if (!kobj || !buf)
 		return -EINVAL;
 
 	if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
-		str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20);
+		offset = sysfs_emit(buf, "ACPI20=0x%lx\n", efi.acpi20);
 	if (efi.acpi != EFI_INVALID_TABLE_ADDR)
-		str += sprintf(str, "ACPI=0x%lx\n", efi.acpi);
+		offset += sysfs_emit_at(buf, offset, "ACPI=0x%lx\n", efi.acpi);
 	/*
 	 * If both SMBIOS and SMBIOS3 entry points are implemented, the
 	 * SMBIOS3 entry point shall be preferred, so we list it first to
 	 * let applications stop parsing after the first match.
 	 */
 	if (efi.smbios3 != EFI_INVALID_TABLE_ADDR)
-		str += sprintf(str, "SMBIOS3=0x%lx\n", efi.smbios3);
+		offset += sysfs_emit_at(buf, offset, "SMBIOS3=0x%lx\n", efi.smbios3);
 	if (efi.smbios != EFI_INVALID_TABLE_ADDR)
-		str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios);
+		offset += sysfs_emit_at(buf, offset, "SMBIOS=0x%lx\n", efi.smbios);
 
-	return str - buf;
+	return offset;
 }
 
 static const struct kobj_attribute efi_attr_systab = __KOBJ_ATTR_RO_MODE(systab, 0400);
@@ -160,7 +160,7 @@ static const struct kobj_attribute efi_attr_systab = __KOBJ_ATTR_RO_MODE(systab,
 static ssize_t fw_platform_size_show(struct kobject *kobj,
 				     const struct kobj_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%d\n", efi_enabled(EFI_64BIT) ? 64 : 32);
+	return sysfs_emit(buf, "%d\n", efi_enabled(EFI_64BIT) ? 64 : 32);
 }
 
 extern __weak const struct kobj_attribute efi_attr_fw_vendor;
@@ -406,7 +406,7 @@ static ssize_t efi_runtime_show(struct kobject *kobj,
 				const struct kobj_attribute *attr,
 				char *buf)
 {
-	return sprintf(buf, "%d\n", efi_enabled(EFI_RUNTIME_SERVICES));
+	return sysfs_emit(buf, "%d\n", efi_enabled(EFI_RUNTIME_SERVICES));
 }
 
 static ssize_t efi_runtime_store(struct kobject *kobj,
-- 
2.56.0.360.g66cac248cb-goog