xapian-core/tests/zlib-vg.c

   1 /* @file zlib-vg.c
   2  * @brief LD_PRELOAD hack to avoid bogus valgrind errors caused by zlib.
   3  */
   4 /* Copyright (C) 2010,2013 Olly Betts
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to
   8  * deal in the Software without restriction, including without limitation the
   9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  10  * sell copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  22  * IN THE SOFTWARE.
  23  */
  24
  25 /* Compile on Linux with:
  26  *   gcc -Wall -W -O2 -fPIC -shared -ldl -o zlib-vg.so zlib-vg.c
  27  */
  28
  29 #define _GNU_SOURCE
  30 #include <dlfcn.h>
  31 #include <unistd.h>
  32 #include <valgrind/memcheck.h>
  33 #include <zlib.h>
  34
  35 static int (*real_deflate)(z_streamp, int) = NULL;
  36
  37 int deflate(z_streamp strm, int flush) {
  38     if (!real_deflate) {
  39         real_deflate = (int (*)(z_streamp, int))dlsym(RTLD_NEXT, "deflate");
  40         if (!real_deflate) _exit(1);
  41     }
  42     (void)VALGRIND_CHECK_MEM_IS_DEFINED(strm->next_in, strm->avail_in);
  43     const unsigned char * start = strm->next_out;
  44     int res = real_deflate(strm, flush);
  45     if (res == Z_OK || res == Z_STREAM_END) {
  46         size_t len = strm->next_out - start;
  47         (void)VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE(start, len);
  48     }
  49     return res;
  50 }