1 files changed, 81 insertions, 5 deletions

diff --git a/include/linux/string.h b/include/linux/string.h
index 4795ee5c50c6..9ba8b4597009 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_STRING_H_
 #define _LINUX_STRING_H_
 
+#include <linux/args.h>
 #include <linux/array_size.h>
 #include <linux/compiler.h>	/* for inline */
 #include <linux/types.h>	/* for size_t */
@@ -66,12 +67,79 @@ extern char * strcpy(char *,const char *);
 #ifndef __HAVE_ARCH_STRNCPY
 extern char * strncpy(char *,const char *, __kernel_size_t);
 #endif
-#ifndef __HAVE_ARCH_STRSCPY
-ssize_t strscpy(char *, const char *, size_t);
-#endif
+ssize_t sized_strscpy(char *, const char *, size_t);
+
+/*
+ * The 2 argument style can only be used when dst is an array with a
+ * known size.
+ */
+#define __strscpy0(dst, src, ...)	\
+	sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst))
+#define __strscpy1(dst, src, size)	sized_strscpy(dst, src, size)
+
+#define __strscpy_pad0(dst, src, ...)	\
+	sized_strscpy_pad(dst, src, sizeof(dst) + __must_be_array(dst))
+#define __strscpy_pad1(dst, src, size)	sized_strscpy_pad(dst, src, size)
+
+/**
+ * strscpy - Copy a C-string into a sized buffer
+ * @dst: Where to copy the string to
+ * @src: Where to copy the string from
+ * @...: Size of destination buffer (optional)
+ *
+ * Copy the source string @src, or as much of it as fits, into the
+ * destination @dst buffer. The behavior is undefined if the string
+ * buffers overlap. The destination @dst buffer is always NUL terminated,
+ * unless it's zero-sized.
+ *
+ * The size argument @... is only required when @dst is not an array, or
+ * when the copy needs to be smaller than sizeof(@dst).
+ *
+ * Preferred to strncpy() since it always returns a valid string, and
+ * doesn't unnecessarily force the tail of the destination buffer to be
+ * zero padded. If padding is desired please use strscpy_pad().
+ *
+ * Returns the number of characters copied in @dst (not including the
+ * trailing %NUL) or -E2BIG if @size is 0 or the copy from @src was
+ * truncated.
+ */
+#define strscpy(dst, src, ...)	\
+	CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
+
+#define sized_strscpy_pad(dest, src, count)	({			\
+	char *__dst = (dest);						\
+	const char *__src = (src);					\
+	const size_t __count = (count);					\
+	ssize_t __wrote;						\
+									\
+	__wrote = sized_strscpy(__dst, __src, __count);			\
+	if (__wrote >= 0 && __wrote < __count)				\
+		memset(__dst + __wrote + 1, 0, __count - __wrote - 1);	\
+	__wrote;							\
+})
 
-/* Wraps calls to strscpy()/memset(), no arch specific code required */
-ssize_t strscpy_pad(char *dest, const char *src, size_t count);
+/**
+ * strscpy_pad() - Copy a C-string into a sized buffer
+ * @dst: Where to copy the string to
+ * @src: Where to copy the string from
+ * @...: 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, the
+ * remaining bytes in the buffer will be filled with %NUL bytes.
+ *
+ * For full explanation of why you may want to consider using the
+ * 'strscpy' functions please see the function docstring for strscpy().
+ *
+ * Returns:
+ * * The number of characters copied (not including the trailing %NULs)
+ * * -E2BIG if count is 0 or @src was truncated.
+ */
+#define strscpy_pad(dst, src, ...)	\
+	CONCATENATE(__strscpy_pad, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
 
 #ifndef __HAVE_ARCH_STRCAT
 extern char * strcat(char *, const char *);
@@ -219,9 +287,17 @@ extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
 extern void *kmemdup_array(const void *src, size_t element_size, size_t count, gfp_t gfp);
 
+/* lib/argv_split.c */
 extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
 extern void argv_free(char **argv);
 
+/* lib/cmdline.c */
+extern int get_option(char **str, int *pint);
+extern char *get_options(const char *str, int nints, int *ints);
+extern unsigned long long memparse(const char *ptr, char **retptr);
+extern bool parse_option_str(const char *str, const char *option);
+extern char *next_arg(char *args, char **param, char **val);
+
 extern bool sysfs_streq(const char *s1, const char *s2);
 int match_string(const char * const *array, size_t n, const char *string);
 int __sysfs_match_string(const char * const *array, size_t n, const char *s);