From 6f27d706054c2d1bd07a25d24f27cd819de0dbeb Mon Sep 17 00:00:00 2001
From: Comma Device <device@comma.ai>
Date: Tue, 13 Apr 2021 13:56:08 -0700
Subject: [PATCH] fix reading procfs files

old-commit-hash: 6f21993915dd64ac145ec8a17686b62d909fc8f1
---
 selfdrive/common/util.cc | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/selfdrive/common/util.cc b/selfdrive/common/util.cc
index 86f29968f6..161a6557c2 100644
--- a/selfdrive/common/util.cc
+++ b/selfdrive/common/util.cc
@@ -1,4 +1,5 @@
 #include <errno.h>
+#include <sstream>
 
 #include "common/util.h"
 
@@ -51,11 +52,20 @@ std::string read_file(const std::string& fn) {
   std::ifstream ifs(fn, std::ios::binary | std::ios::ate);
   if (ifs) {
     std::ifstream::pos_type pos = ifs.tellg();
-    std::string result;
-    result.resize(pos);
-    ifs.seekg(0, std::ios::beg);
-    ifs.read(result.data(), pos);
-    if (ifs) return result;
+    if (pos != std::ios::beg) {
+      std::string result;
+      result.resize(pos);
+      ifs.seekg(0, std::ios::beg);
+      ifs.read(result.data(), pos);
+      if (ifs) {
+        return result;
+      }
+    } else {
+      // handle files created on read, e.g. procfs
+      std::stringstream buffer;
+      buffer << ifs.rdbuf();
+      return buffer.str();
+    }
   }
   return "";
 }