f3913b5b68
Two changes:
1) Detect memory read overruns.
For example:
int main() {
char buf[10];
memcpy(buf, "abcde", sizeof(buf));
sprintf("%s\n", buf);
}
because "abcde" is only 6 bytes, copying 10 bytes from it is a bug.
This particular bug will be detected at compile time. Other similar
bugs may be detected at runtime.
2) Detect overlapping buffers on memcpy()
It is a bug to call memcpy() on buffers which overlap. For
example, the following code is buggy:
char buf3[0x800];
char *first_half = &buf3[0x400];
char *second_half = &buf3[1];
memset(buf3, 0, sizeof(buf3));
memcpy(first_half, second_half, 0x400);
printf("1: %s\n", buf3);
We now detect this at compile and run time.
Change-Id: I092bd89f11f18e08e8a9dda0ca903aaea8e06d91
224 lines
8.2 KiB
C
224 lines
8.2 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _STRING_H_
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#define _STRING_H_
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#include <sys/cdefs.h>
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#include <stddef.h>
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#include <malloc.h>
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__BEGIN_DECLS
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extern void* memccpy(void *, const void *, int, size_t);
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extern void* memchr(const void *, int, size_t) __purefunc;
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extern void* memrchr(const void *, int, size_t) __purefunc;
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extern int memcmp(const void *, const void *, size_t) __purefunc;
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extern void* memcpy(void *, const void *, size_t);
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extern void* memmove(void *, const void *, size_t);
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extern void* memset(void *, int, size_t);
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extern void* memmem(const void *, size_t, const void *, size_t) __purefunc;
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extern void memswap(void *, void *, size_t);
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extern char* index(const char *, int) __purefunc;
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extern char* rindex(const char *, int) __purefunc;
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extern char* strchr(const char *, int) __purefunc;
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extern char* strrchr(const char *, int) __purefunc;
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extern size_t strlen(const char *) __purefunc;
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extern int strcmp(const char *, const char *) __purefunc;
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extern char* strcpy(char *, const char *);
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extern char* strcat(char *, const char *);
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extern int strcasecmp(const char *, const char *) __purefunc;
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extern int strncasecmp(const char *, const char *, size_t) __purefunc;
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extern char* strdup(const char *);
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extern char* strstr(const char *, const char *) __purefunc;
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extern char* strcasestr(const char *haystack, const char *needle) __purefunc;
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extern char* strtok(char *, const char *);
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extern char* strtok_r(char *, const char *, char**);
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extern char* strerror(int);
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extern int strerror_r(int errnum, char *buf, size_t n);
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extern size_t strnlen(const char *, size_t) __purefunc;
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extern char* strncat(char *, const char *, size_t);
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extern char* strndup(const char *, size_t);
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extern int strncmp(const char *, const char *, size_t) __purefunc;
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extern char* strncpy(char *, const char *, size_t);
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extern size_t strlcat(char *, const char *, size_t);
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extern size_t strlcpy(char *, const char *, size_t);
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extern size_t strcspn(const char *, const char *) __purefunc;
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extern char* strpbrk(const char *, const char *) __purefunc;
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extern char* strsep(char **, const char *);
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extern size_t strspn(const char *, const char *);
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extern char* strsignal(int sig);
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extern int strcoll(const char *, const char *) __purefunc;
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extern size_t strxfrm(char *, const char *, size_t);
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#if defined(__BIONIC_FORTIFY_INLINE)
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extern void __memcpy_dest_size_error()
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__attribute__((__error__("memcpy called with size bigger than destination")));
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extern void __memcpy_src_size_error()
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__attribute__((__error__("memcpy called with size bigger than source")));
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extern void __memcpy_overlap_error()
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__attribute__((__error__("memcpy called with overlapping regions")));
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extern void *__memcpy_real(void *, const void *, size_t)
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__asm__(__USER_LABEL_PREFIX__ "memcpy");
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extern void *__memcpy_chk2(void *, const void *, size_t, size_t, size_t);
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__BIONIC_FORTIFY_INLINE
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void *memcpy (void *dest, const void *src, size_t copy_amount) {
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char *d = (char *) dest;
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const char *s = (const char *) src;
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size_t s_len = __builtin_object_size(s, 0);
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size_t d_len = __builtin_object_size(d, 0);
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if (__builtin_constant_p(copy_amount) && (copy_amount > d_len)) {
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__memcpy_dest_size_error();
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}
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if (__builtin_constant_p(copy_amount) && (copy_amount > s_len)) {
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__memcpy_src_size_error();
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}
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if (__builtin_constant_p(d - s) && __builtin_constant_p(copy_amount)
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&& (((size_t)(d - s) < copy_amount) || ((size_t)(s - d) < copy_amount))) {
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__memcpy_overlap_error();
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}
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if (__builtin_constant_p(copy_amount) && __builtin_constant_p(d - s)) {
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return __memcpy_real(dest, src, copy_amount);
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}
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return __memcpy_chk2(dest, src, copy_amount, d_len, s_len);
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}
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__BIONIC_FORTIFY_INLINE
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void *memmove (void *dest, const void *src, size_t len) {
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return __builtin___memmove_chk(dest, src, len, __builtin_object_size (dest, 0));
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}
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__BIONIC_FORTIFY_INLINE
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char *strcpy(char *dest, const char *src) {
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return __builtin___strcpy_chk(dest, src, __builtin_object_size (dest, 0));
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}
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__BIONIC_FORTIFY_INLINE
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char *strncpy(char *dest, const char *src, size_t n) {
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return __builtin___strncpy_chk(dest, src, n, __builtin_object_size (dest, 0));
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}
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__BIONIC_FORTIFY_INLINE
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char *strcat(char *dest, const char *src) {
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return __builtin___strcat_chk(dest, src, __builtin_object_size (dest, 0));
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}
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__BIONIC_FORTIFY_INLINE
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char *strncat(char *dest, const char *src, size_t n) {
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return __builtin___strncat_chk(dest, src, n, __builtin_object_size (dest, 0));
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}
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__BIONIC_FORTIFY_INLINE
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void *memset (void *s, int c, size_t n) {
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return __builtin___memset_chk(s, c, n, __builtin_object_size (s, 0));
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}
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extern size_t __strlcpy_real(char *, const char *, size_t)
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__asm__(__USER_LABEL_PREFIX__ "strlcpy");
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extern void __strlcpy_error()
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__attribute__((__error__("strlcpy called with size bigger than buffer")));
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extern size_t __strlcpy_chk(char *, const char *, size_t, size_t);
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__BIONIC_FORTIFY_INLINE
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size_t strlcpy(char *dest, const char *src, size_t size) {
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size_t bos = __builtin_object_size(dest, 0);
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// Compiler doesn't know destination size. Don't call __strlcpy_chk
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if (bos == (size_t) -1) {
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return __strlcpy_real(dest, src, size);
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}
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// Compiler can prove, at compile time, that the passed in size
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// is always <= the actual object size. Don't call __strlcpy_chk
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if (__builtin_constant_p(size) && (size <= bos)) {
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return __strlcpy_real(dest, src, size);
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}
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// Compiler can prove, at compile time, that the passed in size
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// is always > the actual object size. Force a compiler error.
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if (__builtin_constant_p(size) && (size > bos)) {
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__strlcpy_error();
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}
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return __strlcpy_chk(dest, src, size, bos);
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}
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extern size_t __strlcat_real(char *, const char *, size_t)
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__asm__(__USER_LABEL_PREFIX__ "strlcat");
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extern void __strlcat_error()
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__attribute__((__error__("strlcat called with size bigger than buffer")));
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extern size_t __strlcat_chk(char *, const char *, size_t, size_t);
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__BIONIC_FORTIFY_INLINE
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size_t strlcat(char *dest, const char *src, size_t size) {
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size_t bos = __builtin_object_size(dest, 0);
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// Compiler doesn't know destination size. Don't call __strlcat_chk
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if (bos == (size_t) -1) {
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return __strlcat_real(dest, src, size);
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}
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// Compiler can prove, at compile time, that the passed in size
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// is always <= the actual object size. Don't call __strlcat_chk
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if (__builtin_constant_p(size) && (size <= bos)) {
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return __strlcat_real(dest, src, size);
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}
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// Compiler can prove, at compile time, that the passed in size
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// is always > the actual object size. Force a compiler error.
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if (__builtin_constant_p(size) && (size > bos)) {
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__strlcat_error();
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}
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return __strlcat_chk(dest, src, size, bos);
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}
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#endif /* defined(__BIONIC_FORTIFY_INLINE) */
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__END_DECLS
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#endif /* _STRING_H_ */
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