Avoid passing null pointers to memcpy

src/GdbServerConnection.cc

@@ -237,10 +237,10 @@ void GdbServerConnection::write_packet(const char* data) {
 }
 
 void GdbServerConnection::write_binary_packet(const char* pfx, const uint8_t* data,
-                                        ssize_t num_bytes) {
+                                              ssize_t num_bytes) {
   ssize_t pfx_num_chars = strlen(pfx);
   vector<uint8_t> buf;
-  buf.resize(2 * num_bytes + pfx_num_chars);
+  buf.resize(2 * num_bytes + pfx_num_chars + 1);
   ssize_t buf_num_bytes = 0;
   int i;
 

src/processor_trace_check.cc

@@ -86,10 +86,12 @@ static vector<uint8_t> flatten_vector(const vector<vector<uint8_t>>& data) {
     total_size += d.size();
   }
   ret.resize(total_size);
-  size_t offset = 0;
-  for (const auto& d : data) {
-    memcpy(ret.data() + offset, d.data(), d.size());
-    offset += d.size();
+  if (total_size) {
+    size_t offset = 0;
+    for (const auto& d : data) {
+      memcpy(ret.data() + offset, d.data(), d.size());
+      offset += d.size();
+    }
   }
   return ret;
 }

src/util.cc

@@ -334,9 +334,11 @@ vector<uint8_t> read_pt_data(Task* t, FrameTime global_time) {
   while (true) {
     char buf[1024*1024];
     size_t bytes_read = fread(buf, 1, sizeof(buf), dump_file);
-    size_t current_size = result.size();
-    result.resize(current_size + bytes_read);
-    memcpy(result.data() + current_size, buf, bytes_read);
+    if (bytes_read) {
+      size_t current_size = result.size();
+      result.resize(current_size + bytes_read);
+      memcpy(result.data() + current_size, buf, bytes_read);
+    }
     if (bytes_read < sizeof(buf)) {
       break;
     }