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      1 /******************************************************************************
      2  *
      3  *  Copyright 2015 Google, Inc.
      4  *
      5  *  Licensed under the Apache License, Version 2.0 (the "License");
      6  *  you may not use this file except in compliance with the License.
      7  *  You may obtain a copy of the License at:
      8  *
      9  *  http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  *  Unless required by applicable law or agreed to in writing, software
     12  *  distributed under the License is distributed on an "AS IS" BASIS,
     13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  *  See the License for the specific language governing permissions and
     15  *  limitations under the License.
     16  *
     17  ******************************************************************************/
     18 
     19 /*******************************************************************************
     20  *
     21  *  Filename:      compat.cc
     22  *
     23  *  Description:   Compatibility functions for non-bionic C libraries
     24  *
     25  *
     26  ******************************************************************************/
     27 
     28 #include <features.h>
     29 #include <string.h>
     30 #include <sys/syscall.h>
     31 #include <sys/types.h>
     32 #include <unistd.h>
     33 
     34 #include "osi/include/compat.h"
     35 #include "osi/include/osi.h"
     36 
     37 #if __GLIBC__
     38 pid_t gettid(void) { return syscall(SYS_gettid); }
     39 #endif
     40 
     41 /* These functions from bionic
     42  *
     43  * Copyright (c) 1998 Todd C. Miller <Todd.Miller (at) courtesan.com>
     44  *
     45  * Permission to use, copy, modify, and distribute this software for any
     46  * purpose with or without fee is hereby granted, provided that the above
     47  * copyright notice and this permission notice appear in all copies.
     48  *
     49  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     50  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     51  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     52  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     53  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     54  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     55  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     56  */
     57 
     58 #if __GLIBC__
     59 /*
     60  * Copy src to string dst of size siz.  At most siz-1 characters
     61  * will be copied.  Always NUL terminates (unless siz == 0).
     62  * Returns strlen(src); if retval >= siz, truncation occurred.
     63  */
     64 size_t strlcpy(char* dst, const char* src, size_t siz) {
     65   char* d = dst;
     66   const char* s = src;
     67   size_t n = siz;
     68 
     69   /* Copy as many bytes as will fit */
     70   if (n != 0) {
     71     while (--n != 0) {
     72       if ((*d++ = *s++) == '\0') break;
     73     }
     74   }
     75 
     76   /* Not enough room in dst, add NUL and traverse rest of src */
     77   if (n == 0) {
     78     if (siz != 0) *d = '\0'; /* NUL-terminate dst */
     79     while (*s++)
     80       ;
     81   }
     82 
     83   return (s - src - 1); /* count does not include NUL */
     84 }
     85 #endif
     86 
     87 #if __GLIBC__
     88 /*
     89  * Appends src to string dst of size siz (unlike strncat, siz is the
     90  * full size of dst, not space left).  At most siz-1 characters
     91  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
     92  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
     93  * If retval >= siz, truncation occurred.
     94  */
     95 size_t strlcat(char* dst, const char* src, size_t siz) {
     96   char* d = dst;
     97   const char* s = src;
     98   size_t n = siz;
     99   size_t dlen;
    100 
    101   /* Find the end of dst and adjust bytes left but don't go past end */
    102   while (n-- != 0 && *d != '\0') d++;
    103   dlen = d - dst;
    104   n = siz - dlen;
    105 
    106   if (n == 0) return (dlen + strlen(s));
    107 
    108   while (*s != '\0') {
    109     if (n != 1) {
    110       *d++ = *s;
    111       n--;
    112     }
    113 
    114     s++;
    115   }
    116 
    117   *d = '\0';
    118 
    119   return (dlen + (s - src)); /* count does not include NUL */
    120 }
    121 #endif
    122