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      1 // Copyright (c) 2009, Google Inc.
      2 // All rights reserved.
      3 //
      4 // Redistribution and use in source and binary forms, with or without
      5 // modification, are permitted provided that the following conditions are
      6 // met:
      7 //
      8 //     * Redistributions of source code must retain the above copyright
      9 // notice, this list of conditions and the following disclaimer.
     10 //     * Redistributions in binary form must reproduce the above
     11 // copyright notice, this list of conditions and the following disclaimer
     12 // in the documentation and/or other materials provided with the
     13 // distribution.
     14 //     * Neither the name of Google Inc. nor the names of its
     15 // contributors may be used to endorse or promote products derived from
     16 // this software without specific prior written permission.
     17 //
     18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29 
     30 // This header provides replacements for libc functions that we need. We if
     31 // call the libc functions directly we risk crashing in the dynamic linker as
     32 // it tries to resolve uncached PLT entries.
     33 
     34 #ifndef CLIENT_LINUX_LINUX_LIBC_SUPPORT_H_
     35 #define CLIENT_LINUX_LINUX_LIBC_SUPPORT_H_
     36 
     37 #include <stdint.h>
     38 #include <limits.h>
     39 #include <sys/types.h>
     40 
     41 extern "C" {
     42 
     43 extern size_t my_strlen(const char* s);
     44 
     45 extern int my_strcmp(const char* a, const char* b);
     46 
     47 extern int my_strncmp(const char* a, const char* b, size_t len);
     48 
     49 // Parse a non-negative integer.
     50 //   result: (output) the resulting non-negative integer
     51 //   s: a NUL terminated string
     52 // Return true iff successful.
     53 extern bool my_strtoui(int* result, const char* s);
     54 
     55 // Return the length of the given unsigned integer when expressed in base 10.
     56 extern unsigned my_uint_len(uintmax_t i);
     57 
     58 // Convert an unsigned integer to a string
     59 //   output: (output) the resulting string is written here. This buffer must be
     60 //     large enough to hold the resulting string. Call |my_uint_len| to get the
     61 //     required length.
     62 //   i: the unsigned integer to serialise.
     63 //   i_len: the length of the integer in base 10 (see |my_uint_len|).
     64 extern void my_uitos(char* output, uintmax_t i, unsigned i_len);
     65 
     66 extern const char* my_strchr(const char* haystack, char needle);
     67 
     68 extern const char* my_strrchr(const char* haystack, char needle);
     69 
     70 // Read a hex value
     71 //   result: (output) the resulting value
     72 //   s: a string
     73 // Returns a pointer to the first invalid charactor.
     74 extern const char* my_read_hex_ptr(uintptr_t* result, const char* s);
     75 
     76 extern const char* my_read_decimal_ptr(uintptr_t* result, const char* s);
     77 
     78 extern void my_memset(void* ip, char c, size_t len);
     79 
     80 extern void* my_memchr(const void* src, int c, size_t len);
     81 
     82 // The following are considered safe to use in a compromised environment.
     83 // Besides, this gives the compiler an opportunity to optimize their calls.
     84 #define my_memcpy  memcpy
     85 #define my_memmove memmove
     86 #define my_memcmp  memcmp
     87 
     88 extern size_t my_strlcpy(char* s1, const char* s2, size_t len);
     89 
     90 extern size_t my_strlcat(char* s1, const char* s2, size_t len);
     91 
     92 extern int my_isspace(int ch);
     93 
     94 }  // extern "C"
     95 
     96 #endif  // CLIENT_LINUX_LINUX_LIBC_SUPPORT_H_
     97