Feedback; add sanitizer_common test

Author: ccotter

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

@@ -1265,16 +1265,9 @@ INTERCEPTOR(int, prctl, int option, unsigned long arg2, unsigned long arg3,
     internal_strncpy(buff, (char *)arg2, 15);
     buff[15] = 0;
     COMMON_INTERCEPTOR_SET_THREAD_NAME(ctx, buff);
-  } else if (res != 1 && option == PR_GET_NAME) {
-    unsigned long null_index = 0;
+  } else if (res == 0 && option == PR_GET_NAME) {
     char *name = (char *)arg2;
-    while (null_index < 16 && name[null_index]) {
-      ++null_index;
-    }
-    if (null_index > 15) {
-      null_index = 15;
-    }
-    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, (u64 *)arg2, null_index + 1);
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, name, internal_strlen(name) + 1);
   } else if (res != -1 && option == PR_SCHED_CORE &&
              arg2 == PR_SCHED_CORE_GET) {
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, (u64*)(arg5), sizeof(u64));

compiler-rt/test/msan/prctl.cpp renamed to compiler-rt/test/msan/Linux/prctl.cpp

@@ -1,5 +1,4 @@
 // RUN: %clangxx_msan -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s
-// REQUIRES: linux
 
 #include <linux/prctl.h>
 #include <sys/prctl.h>

compiler-rt/test/sanitizer_common/TestCases/Linux/prctl.cpp

@@ -3,6 +3,7 @@
 #include <assert.h>
 #include <errno.h>
 #include <stdint.h>
+#include <string.h>
 #include <sys/mman.h>
 #include <sys/prctl.h>
 
@@ -60,5 +61,14 @@ int main() {
   }
   munmap(p, 128);
 
+  res = prctl(PR_SET_NAME, "tname");
+  if (res == 0) {
+    char name[16];
+    res = prctl(PR_GET_NAME, name);
+    if (res == 0) {
+        assert(!strcmp(name, "tname"));
+    }
+  }
+
   return 0;
 }