Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * User address space access functions. | |
3 | * | |
4 | * Copyright 1997 Andi Kleen <ak@muc.de> | |
5 | * Copyright 1997 Linus Torvalds | |
6 | * Copyright 2002 Andi Kleen <ak@suse.de> | |
7 | */ | |
2ee60e17 | 8 | #include <linux/module.h> |
1da177e4 LT |
9 | #include <asm/uaccess.h> |
10 | ||
11 | /* | |
12 | * Copy a null terminated string from userspace. | |
13 | */ | |
14 | ||
15 | #define __do_strncpy_from_user(dst,src,count,res) \ | |
16 | do { \ | |
17 | long __d0, __d1, __d2; \ | |
3ee1afa3 | 18 | might_fault(); \ |
1da177e4 LT |
19 | __asm__ __volatile__( \ |
20 | " testq %1,%1\n" \ | |
21 | " jz 2f\n" \ | |
22 | "0: lodsb\n" \ | |
23 | " stosb\n" \ | |
24 | " testb %%al,%%al\n" \ | |
25 | " jz 1f\n" \ | |
26 | " decq %1\n" \ | |
27 | " jnz 0b\n" \ | |
28 | "1: subq %1,%0\n" \ | |
29 | "2:\n" \ | |
30 | ".section .fixup,\"ax\"\n" \ | |
31 | "3: movq %5,%0\n" \ | |
32 | " jmp 2b\n" \ | |
33 | ".previous\n" \ | |
8da804f2 | 34 | _ASM_EXTABLE(0b,3b) \ |
1da177e4 LT |
35 | : "=r"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1), \ |
36 | "=&D" (__d2) \ | |
37 | : "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \ | |
38 | : "memory"); \ | |
39 | } while (0) | |
40 | ||
41 | long | |
42 | __strncpy_from_user(char *dst, const char __user *src, long count) | |
43 | { | |
44 | long res; | |
45 | __do_strncpy_from_user(dst, src, count, res); | |
46 | return res; | |
47 | } | |
2ee60e17 | 48 | EXPORT_SYMBOL(__strncpy_from_user); |
1da177e4 LT |
49 | |
50 | long | |
51 | strncpy_from_user(char *dst, const char __user *src, long count) | |
52 | { | |
53 | long res = -EFAULT; | |
54 | if (access_ok(VERIFY_READ, src, 1)) | |
6bfa9bb5 | 55 | return __strncpy_from_user(dst, src, count); |
1da177e4 LT |
56 | return res; |
57 | } | |
2ee60e17 | 58 | EXPORT_SYMBOL(strncpy_from_user); |
1da177e4 LT |
59 | |
60 | /* | |
61 | * Zero Userspace | |
62 | */ | |
63 | ||
64 | unsigned long __clear_user(void __user *addr, unsigned long size) | |
65 | { | |
66 | long __d0; | |
3ee1afa3 | 67 | might_fault(); |
1da177e4 LT |
68 | /* no memory constraint because it doesn't change any memory gcc knows |
69 | about */ | |
70 | asm volatile( | |
71 | " testq %[size8],%[size8]\n" | |
72 | " jz 4f\n" | |
73 | "0: movq %[zero],(%[dst])\n" | |
74 | " addq %[eight],%[dst]\n" | |
75 | " decl %%ecx ; jnz 0b\n" | |
76 | "4: movq %[size1],%%rcx\n" | |
77 | " testl %%ecx,%%ecx\n" | |
78 | " jz 2f\n" | |
79 | "1: movb %b[zero],(%[dst])\n" | |
80 | " incq %[dst]\n" | |
81 | " decl %%ecx ; jnz 1b\n" | |
82 | "2:\n" | |
83 | ".section .fixup,\"ax\"\n" | |
84 | "3: lea 0(%[size1],%[size8],8),%[size8]\n" | |
85 | " jmp 2b\n" | |
86 | ".previous\n" | |
8da804f2 PA |
87 | _ASM_EXTABLE(0b,3b) |
88 | _ASM_EXTABLE(1b,2b) | |
1da177e4 LT |
89 | : [size8] "=c"(size), [dst] "=&D" (__d0) |
90 | : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr), | |
91 | [zero] "r" (0UL), [eight] "r" (8UL)); | |
92 | return size; | |
93 | } | |
2ee60e17 | 94 | EXPORT_SYMBOL(__clear_user); |
1da177e4 LT |
95 | |
96 | unsigned long clear_user(void __user *to, unsigned long n) | |
97 | { | |
98 | if (access_ok(VERIFY_WRITE, to, n)) | |
99 | return __clear_user(to, n); | |
100 | return n; | |
101 | } | |
2ee60e17 | 102 | EXPORT_SYMBOL(clear_user); |
1da177e4 LT |
103 | |
104 | /* | |
105 | * Return the size of a string (including the ending 0) | |
106 | * | |
107 | * Return 0 on exception, a value greater than N if too long | |
108 | */ | |
109 | ||
5f1d189f | 110 | long __strnlen_user(const char __user *s, long n) |
1da177e4 LT |
111 | { |
112 | long res = 0; | |
113 | char c; | |
114 | ||
1da177e4 LT |
115 | while (1) { |
116 | if (res>n) | |
117 | return n+1; | |
118 | if (__get_user(c, s)) | |
119 | return 0; | |
120 | if (!c) | |
121 | return res+1; | |
122 | res++; | |
123 | s++; | |
124 | } | |
125 | } | |
2ee60e17 | 126 | EXPORT_SYMBOL(__strnlen_user); |
1da177e4 | 127 | |
5f1d189f JB |
128 | long strnlen_user(const char __user *s, long n) |
129 | { | |
130 | if (!access_ok(VERIFY_READ, s, n)) | |
131 | return 0; | |
132 | return __strnlen_user(s, n); | |
133 | } | |
2ee60e17 | 134 | EXPORT_SYMBOL(strnlen_user); |
5f1d189f | 135 | |
1da177e4 LT |
136 | long strlen_user(const char __user *s) |
137 | { | |
138 | long res = 0; | |
139 | char c; | |
140 | ||
141 | for (;;) { | |
142 | if (get_user(c, s)) | |
143 | return 0; | |
144 | if (!c) | |
145 | return res+1; | |
146 | res++; | |
147 | s++; | |
148 | } | |
149 | } | |
2ee60e17 | 150 | EXPORT_SYMBOL(strlen_user); |
1da177e4 LT |
151 | |
152 | unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len) | |
153 | { | |
154 | if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) { | |
155 | return copy_user_generic((__force void *)to, (__force void *)from, len); | |
156 | } | |
157 | return len; | |
158 | } | |
2ee60e17 AK |
159 | EXPORT_SYMBOL(copy_in_user); |
160 | ||
1129585a VM |
161 | /* |
162 | * Try to copy last bytes and clear the rest if needed. | |
163 | * Since protection fault in copy_from/to_user is not a normal situation, | |
164 | * it is not necessary to optimize tail handling. | |
165 | */ | |
166 | unsigned long | |
167 | copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest) | |
168 | { | |
169 | char c; | |
170 | unsigned zero_len; | |
171 | ||
172 | for (; len; --len) { | |
173 | if (__get_user_nocheck(c, from++, sizeof(char))) | |
174 | break; | |
175 | if (__put_user_nocheck(c, to++, sizeof(char))) | |
176 | break; | |
177 | } | |
178 | ||
179 | for (c = 0, zero_len = len; zerorest && zero_len; --zero_len) | |
180 | if (__put_user_nocheck(c, to++, sizeof(char))) | |
181 | break; | |
182 | return len; | |
183 | } |