Merge tag 'linux-kselftest-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kselftest updates from Shuah Khan:

 - fixes to seccomp test, and kselftest framework

 - cleanups to remove duplicate header defines

 - fixes to efivarfs "make clean" target

 - cgroup cleanup path

 - Moving the IMA kexec_load selftest to selftests/kexec work from Mimi
   Johar and Petr Vorel

 - A framework to kselftest for writing kernel test modules addition
   from Tobin C. Harding

* tag 'linux-kselftest-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (29 commits)
  selftests: build and run gpio when output directory is the src dir
  selftests/ipc: Fix msgque compiler warnings
  selftests/efivarfs: clean up test files from test_create*()
  selftests: fix headers_install circular dependency
  selftests/kexec: update get_secureboot_mode
  selftests/kexec: make kexec_load test independent of IMA being enabled
  selftests/kexec: check kexec_load and kexec_file_load are enabled
  selftests/kexec: Add missing '=y' to config options
  selftests/kexec: kexec_file_load syscall test
  selftests/kexec: define "require_root_privileges"
  selftests/kexec: define common logging functions
  selftests/kexec: define a set of common functions
  selftests/kexec: cleanup the kexec selftest
  selftests/kexec: move the IMA kexec_load selftest to selftests/kexec
  selftests/harness: Add 30 second timeout per test
  selftests/seccomp: Handle namespace failures gracefully
  selftests: cgroup: fix cleanup path in test_memcg_subtree_control()
  selftests: efivarfs: remove the test_create_read file if it was exist
  rseq/selftests: Adapt number of threads to the number of detected cpus
  lib: Add test module for strscpy_pad
  ...

1 files changed, 40 insertions, 7 deletions

diff --git a/lib/string.c b/lib/string.c
index 3ab861c1a857..6016eb3ac73d 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -159,11 +159,9 @@ EXPORT_SYMBOL(strlcpy);
  * @src: Where to copy the string from
  * @count: Size of destination buffer
  *
- * Copy the string, or as much of it as fits, into the dest buffer.
- * The routine returns the number of characters copied (not including
- * the trailing NUL) or -E2BIG if the destination buffer wasn't big enough.
- * The behavior is undefined if the string buffers overlap.
- * The destination buffer is always NUL terminated, unless it's zero-sized.
+ * Copy the string, or as much of it as fits, into the dest buffer.  The
+ * behavior is undefined if the string buffers overlap.  The destination
+ * buffer is always NUL terminated, unless it's zero-sized.
  *
  * Preferred to strlcpy() since the API doesn't require reading memory
  * from the src string beyond the specified "count" bytes, and since
@@ -173,8 +171,10 @@ EXPORT_SYMBOL(strlcpy);
  *
  * Preferred to strncpy() since it always returns a valid string, and
  * doesn't unnecessarily force the tail of the destination buffer to be
- * zeroed.  If the zeroing is desired, it's likely cleaner to use strscpy()
- * with an overflow test, then just memset() the tail of the dest buffer.
+ * zeroed.  If zeroing is desired please use strscpy_pad().
+ *
+ * Return: The number of characters copied (not including the trailing
+ *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
  */
 ssize_t strscpy(char *dest, const char *src, size_t count)
 {
@@ -237,6 +237,39 @@ ssize_t strscpy(char *dest, const char *src, size_t count)
 EXPORT_SYMBOL(strscpy);
 #endif
 
+/**
+ * strscpy_pad() - Copy a C-string into a sized buffer
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @count: Size of destination buffer
+ *
+ * Copy the string, or as much of it as fits, into the dest buffer.  The
+ * behavior is undefined if the string buffers overlap.  The destination
+ * buffer is always %NUL terminated, unless it's zero-sized.
+ *
+ * If the source string is shorter than the destination buffer, zeros
+ * the tail of the destination buffer.
+ *
+ * For full explanation of why you may want to consider using the
+ * 'strscpy' functions please see the function docstring for strscpy().
+ *
+ * Return: The number of characters copied (not including the trailing
+ *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
+ */
+ssize_t strscpy_pad(char *dest, const char *src, size_t count)
+{
+	ssize_t written;
+
+	written = strscpy(dest, src, count);
+	if (written < 0 || written == count - 1)
+		return written;
+
+	memset(dest + written + 1, 0, count - written - 1);
+
+	return written;
+}
+EXPORT_SYMBOL(strscpy_pad);
+
 #ifndef __HAVE_ARCH_STRCAT
 /**
  * strcat - Append one %NUL-terminated string to another