patch-2.4.20 linux-2.4.20/arch/x86_64/lib/usercopy.c

• Lines: 129
• Date: Thu Nov 28 15:53:12 2002
• Orig file: linux-2.4.19/arch/x86_64/lib/usercopy.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/x86_64/lib/usercopy.c linux-2.4.20/arch/x86_64/lib/usercopy.c
@@ -0,0 +1,128 @@
+/* 
+ * User address space access functions.
+ *
+ * Copyright 1997 Andi Kleen <ak@muc.de>
+ * Copyright 1997 Linus Torvalds
+ * Copyright 2002 Andi Kleen <ak@suse.de>
+ */
+#include <asm/uaccess.h>
+
+/*
+ * Copy a null terminated string from userspace.
+ */
+
+#define __do_strncpy_from_user(dst,src,count,res)			   \
+do {									   \
+	long __d0, __d1, __d2;						   \
+	__asm__ __volatile__(						   \
+		"	testq %1,%1\n"					   \
+		"	jz 2f\n"					   \
+		"0:	lodsb\n"					   \
+		"	stosb\n"					   \
+		"	testb %%al,%%al\n"				   \
+		"	jz 1f\n"					   \
+		"	decq %1\n"					   \
+		"	jnz 0b\n"					   \
+		"1:	subq %1,%0\n"					   \
+		"2:\n"							   \
+		".section .fixup,\"ax\"\n"				   \
+		"3:	movq %5,%0\n"					   \
+		"	jmp 2b\n"					   \
+		".previous\n"						   \
+		".section __ex_table,\"a\"\n"				   \
+		"	.align 4\n"					   \
+		"	.quad 0b,3b\n"					   \
+		".previous"						   \
+		: "=r"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1),	   \
+		  "=&D" (__d2)						   \
+		: "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \
+		: "memory");						   \
+} while (0)
+
+long
+__strncpy_from_user(char *dst, const char *src, long count)
+{
+	long res;
+	__do_strncpy_from_user(dst, src, count, res);
+	return res;
+}
+
+long
+strncpy_from_user(char *dst, const char *src, long count)
+{
+	long res = -EFAULT;
+	if (access_ok(VERIFY_READ, src, 1))
+		__do_strncpy_from_user(dst, src, count, res);
+	return res;
+}
+
+/*
+ * Zero Userspace
+ */
+
+unsigned long __clear_user(void *addr, unsigned long size)
+{
+	long __d0;
+	/* no memory constraint because it doesn't change any memory gcc knows
+	   about */
+	asm volatile(
+		"	testq  %[size8],%[size8]\n"
+		"	jz     4f\n"
+		"0:	movnti %[zero],(%[dst])\n"
+		"	addq   %[eight],%[dst]\n"
+		"	decl %%ecx ; jnz   0b\n"
+		"4:	movq  %[size1],%%rcx\n"
+		"	testl %%ecx,%%ecx\n"
+		"	jz     2f\n"
+		"1:	movb   %b[zero],(%[dst])\n"
+		"	incq   %[dst]\n"
+		"	decl %%ecx ; jnz  1b\n"
+		"2:	sfence\n"
+		".section .fixup,\"ax\"\n"
+		"3:	lea 0(%[size1],%[size8],8),%[size8]\n"
+		"	jmp 2b\n"
+		".previous\n"
+		".section __ex_table,\"a\"\n"
+		"       .align 8\n"
+		"	.quad 0b,3b\n"
+		"	.quad 1b,2b\n"
+		".previous"
+		: [size8] "=c"(size), [dst] "=&D" (__d0)
+		: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst] "(addr),
+		  [zero] "r" (0UL), [eight] "r" (8UL));
+	return size;
+}
+
+
+unsigned long clear_user(void *to, unsigned long n)
+{
+	if (access_ok(VERIFY_WRITE, to, n))
+		return __clear_user(to, n);
+	return n;
+}
+
+/*
+ * Return the size of a string (including the ending 0)
+ *
+ * Return 0 on exception, a value greater than N if too long
+ */
+
+long strnlen_user(const char *s, long n)
+{
+	unsigned long res = 0;
+	char c;
+
+	if (!access_ok(VERIFY_READ, s, n))
+		return 0;
+
+	while (1) {
+		if (get_user(c, s))
+			return 0;
+		if (!c)
+			return res+1;
+		if (res>n)
+			return n+1;
+		res++;
+		s++;
+	}
+}