[Sanitizer] add sanity checks for communication with external symbolizer

llvm-svn: 167617

compiler-rt/lib/sanitizer_common/sanitizer_common.h

@@ -117,6 +117,7 @@ void *MapFileToMemory(const char *file_name, uptr *buff_size);
 // OS
 void DisableCoreDumper();
 void DumpProcessMap();
+bool FileExists(const char *filename);
 const char *GetEnv(const char *name);
 const char *GetPwd();
 void ReExec();

compiler-rt/lib/sanitizer_common/sanitizer_linux.cc

@@ -94,6 +94,20 @@ int internal_sched_yield() {
 }
 
 // ----------------- sanitizer_common.h
+bool FileExists(const char *filename) {
+#if __WORDSIZE == 64
+  struct stat st;
+  if (syscall(__NR_stat, filename, &st))
+    return false;
+#else
+  struct stat64 st;
+  if (syscall(__NR_stat64, filename, &st))
+    return false;
+#endif
+  // Sanity check: filename is a regular file.
+  return S_ISREG(st.st_mode);
+}
+
 uptr GetTid() {
   return syscall(__NR_gettid);
 }

compiler-rt/lib/sanitizer_common/sanitizer_mac.cc

@@ -80,6 +80,14 @@ int internal_sched_yield() {
 }
 
 // ----------------- sanitizer_common.h
+bool FileExists(const char *filename) {
+  struct stat st;
+  if (stat(filename, &st))
+    return false;
+  // Sanity check: filename is a regular file.
+  return S_ISREG(st.st_mode);
+}
+
 uptr GetTid() {
   return reinterpret_cast<uptr>(pthread_self());
 }

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_linux.cc

@@ -23,6 +23,7 @@
 #include <poll.h>
 #include <sys/socket.h>
 #include <sys/types.h>
+#include <sys/wait.h>
 #include <unistd.h>
 
 #if !defined(__ANDROID__) && !defined(ANDROID)
@@ -31,8 +32,15 @@
 
 namespace __sanitizer {
 
+static const int kSymbolizerStartupTimeMillis = 10;
+
 bool StartSymbolizerSubprocess(const char *path_to_symbolizer,
                                int *input_fd, int *output_fd) {
+  if (!FileExists(path_to_symbolizer)) {
+    Report("WARNING: invalid path to external symbolizer!\n");
+    return false;
+  }
+
   int *infd = NULL;
   int *outfd = NULL;
   // The client program may close its stdin and/or stdout and/or stderr
@@ -99,6 +107,17 @@ bool StartSymbolizerSubprocess(const char *path_to_symbolizer,
   internal_close(infd[1]);
   *input_fd = infd[0];
   *output_fd = outfd[1];
+
+  // Check that symbolizer subprocess started successfully.
+  int pid_status;
+  SleepForMillis(kSymbolizerStartupTimeMillis);
+  int exited_pid = waitpid(pid, &pid_status, WNOHANG);
+  if (exited_pid != 0) {
+    // Either waitpid failed, or child has already exited.
+    Report("WARNING: external symbolizer didn't start up correctly!\n");
+    return false;
+  }
+
   return true;
 }
 

compiler-rt/lib/sanitizer_common/sanitizer_win.cc

@@ -23,6 +23,10 @@
 namespace __sanitizer {
 
 // --------------------- sanitizer_common.h
+bool FileExists(const char *filename) {
+  UNIMPLEMENTED();
+}
+
 int GetPid() {
   return GetProcessId(GetCurrentProcess());
 }

compiler-rt/lib/tsan/rtl/tsan_rtl.cc

@@ -197,7 +197,11 @@ void Initialize(ThreadState *thr) {
   // Initialize external symbolizer before internal threads are started.
   const char *external_symbolizer = flags()->external_symbolizer_path;
   if (external_symbolizer != 0 && external_symbolizer[0] != '\0') {
-    InitializeExternalSymbolizer(external_symbolizer);
+    if (!InitializeExternalSymbolizer(external_symbolizer)) {
+      Printf("Failed to start external symbolizer: '%s'\n",
+             external_symbolizer);
+      Die();
+    }
   }
 #endif
   InitializeMemoryProfile();