[asan] Fix filename size on linux platforms.

[yroux]

Summary

This is a a fix for:
https://bugs.llvm.org/show_bug.cgi?id=35996

Use filename limits from system headers to be synchronized with what LD_PRELOAD can handle.

Passed regression tests on x86_64 without regressions.

[vitalybuka]

lib/asan/asan_linux.cc

218

please use PATH_MAX from <limits.h>

[yroux]

Use PATH_MAX from <limits.h> instead of MAXPATHLEN.

[hans]

Yvan, please go ahead and commit. I'd like this included in llvm-6.0.0-rc2, which I'd like to get out today.

[yroux]

Sorry for the delay Hans (I was off today) Hope it is not too late to include it in rc2.

lib/asan/asan_linux.cc

 #include "asan_premap_shadow.h"
 #include "asan_thread.h"
 #include "sanitizer_common/sanitizer_flags.h"
 #include "sanitizer_common/sanitizer_freebsd.h"
 #include "sanitizer_common/sanitizer_libc.h"
 #include "sanitizer_common/sanitizer_procmaps.h"
 
 #include <sys/time.h>
+#include <sys/param.h>
 #include <sys/resource.h>
 #include <sys/mman.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <dlfcn.h>
 #include <fcntl.h>
 #include <pthread.h>
 #include <stdio.h>
if (ASAN_DYNAMIC) {
     }
   } else {
     if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) {
       // Ensure that dynamic runtime is not present. We should detect it
       // as early as possible, otherwise ASan interceptors could bind to
       // the functions in dynamic ASan runtime instead of the functions in
       // system libraries, causing crashes later in ASan initialization.
       MemoryMappingLayout proc_maps(/*cache_enabled*/true);
-      char filename[128];
+      char filename[MAXPATHLEN];
       MemoryMappedSegment segment(filename, sizeof(filename));
       while (proc_maps.Next(&segment)) {
         if (IsDynamicRTName(segment.filename)) {
           Report("Your application is linked against "
                  "incompatible ASan runtimes.\n");
           Die();
         }
       }