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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 | /* * 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; \ might_sleep(); \ __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 8\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 __user *src, long count) { long res; __do_strncpy_from_user(dst, src, count, res); return res; } long strncpy_from_user(char *dst, const char __user *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 __user *addr, unsigned long size) { long __d0; might_sleep(); /* no memory constraint because it doesn't change any memory gcc knows about */ asm volatile( " testq %[size8],%[size8]\n" " jz 4f\n" "0: movq %[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:\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 __user *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 __user *s, long n) { long res = 0; char c; if (!access_ok(VERIFY_READ, s, n)) return 0; while (1) { if (res>n) return n+1; if (__get_user(c, s)) return 0; if (!c) return res+1; res++; s++; } } long strlen_user(const char __user *s) { long res = 0; char c; for (;;) { if (get_user(c, s)) return 0; if (!c) return res+1; res++; s++; } } unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len) { if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) { return copy_user_generic((__force void *)to, (__force void *)from, len); } return len; } |