[sanitizer] Add interceptor for ttyname_r

[eugenis]

Looks good.
Add a test, please.

[loladiro]

Add a test

[eugenis]

LGTM

lib/sanitizer_common/sanitizer_common_interceptors.inc

INTERCEPTOR(char *, tmpnam_r, char *s) {
   if (res && s) COMMON_INTERCEPTOR_WRITE_RANGE(ctx, s, REAL(strlen)(s) + 1);
   return res;
 }
 #define INIT_TMPNAM_R COMMON_INTERCEPT_FUNCTION(tmpnam_r);
 #else
 #define INIT_TMPNAM_R
 #endif
 
+#if SANITIZER_INTERCEPT_TTYNAME_R
+INTERCEPTOR(int, ttyname_r, int fd, char *name, SIZE_T namesize) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, ttyname_r, fd, name, namesize);
+  int res = REAL(ttyname_r)(fd, name, namesize);
+  if (res == 0)
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, name, REAL(strlen)(name) + 1);
+  return res;
+}
+#define INIT_TTYNAME_R COMMON_INTERCEPT_FUNCTION(ttyname_r);
+#else
+#define INIT_TTYNAME_R
+#endif
+
 #if SANITIZER_INTERCEPT_TEMPNAM
 INTERCEPTOR(char *, tempnam, char *dir, char *pfx) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, tempnam, dir, pfx);
   if (dir) COMMON_INTERCEPTOR_READ_RANGE(ctx, dir, REAL(strlen)(dir) + 1);
   if (pfx) COMMON_INTERCEPTOR_READ_RANGE(ctx, pfx, REAL(strlen)(pfx) + 1);
   char *res = REAL(tempnam)(dir, pfx);
   if (res) COMMON_INTERCEPTOR_INITIALIZE_RANGE(res, REAL(strlen)(res) + 1);
static void InitializeCommonInterceptors() {
   INIT_PTHREAD_MUTEXATTR_GETROBUST_NP;
   INIT_PTHREAD_RWLOCKATTR_GETPSHARED;
   INIT_PTHREAD_RWLOCKATTR_GETKIND_NP;
   INIT_PTHREAD_CONDATTR_GETPSHARED;
   INIT_PTHREAD_CONDATTR_GETCLOCK;
   INIT_PTHREAD_BARRIERATTR_GETPSHARED;
   INIT_TMPNAM;
   INIT_TMPNAM_R;
+  INIT_TTYNAME_R;
   INIT_TEMPNAM;
   INIT_PTHREAD_SETNAME_NP;
   INIT_SINCOS;
   INIT_REMQUO;
   INIT_LGAMMA;
   INIT_LGAMMA_R;
   INIT_LGAMMAL_R;
   INIT_DRAND48_R;

lib/sanitizer_common/sanitizer_platform_interceptors.h

 #define SANITIZER_INTERCEPT_PTHREAD_MUTEXATTR_GETROBUST_NP SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_PTHREAD_RWLOCKATTR_GETPSHARED SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_PTHREAD_RWLOCKATTR_GETKIND_NP SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_PTHREAD_CONDATTR_GETPSHARED SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_PTHREAD_CONDATTR_GETCLOCK SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_PTHREAD_BARRIERATTR_GETPSHARED SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_TMPNAM SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_TMPNAM_R SI_LINUX_NOT_ANDROID
+#define SANITIZER_INTERCEPT_TTYNAME_R SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_TEMPNAM SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_SINCOS SI_LINUX
 #define SANITIZER_INTERCEPT_REMQUO SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_LGAMMA SI_NOT_WINDOWS
 #define SANITIZER_INTERCEPT_LGAMMA_R SI_FREEBSD || SI_LINUX
 #define SANITIZER_INTERCEPT_LGAMMAL_R SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_DRAND48_R SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_RAND_R \

test/msan/Linux/forkpty.cc

 // RUN: %clangxx_msan -O0 -g %s -lutil -o %t && %run %t
 
 #include <assert.h>
 #include <pty.h>
+#include <unistd.h>
+#include <cstring>
 
 #include <sanitizer/msan_interface.h>
 
 int
 main (int argc, char** argv)
 {
   int master, slave;
   openpty(&master, &slave, NULL, NULL, NULL);
   assert(__msan_test_shadow(&master, sizeof(master)) == -1);
   assert(__msan_test_shadow(&slave, sizeof(slave)) == -1);
 
+  char ttyname[255];
+  ttyname_r(master, ttyname, sizeof(ttyname));
+  assert(__msan_test_shadow(ttyname, strlen(ttyname) + 1) == -1);
+
   int master2;
   forkpty(&master2, NULL, NULL, NULL);
   assert(__msan_test_shadow(&master2, sizeof(master2)) == -1);
 }