Be more careful with fread in various places.v2.13.88

1 files changed, 15 insertions, 2 deletions

diff --git a/src/lib/util.cc b/src/lib/util.cc
index 051a4bb25..5eba8d73a 100644
--- a/src/lib/util.cc
+++ b/src/lib/util.cc
@@ -444,7 +444,7 @@ digest_head_tail (vector<boost::filesystem::path> files, boost::uintmax_t size)
 		}
 
 		boost::uintmax_t this_time = min (to_do, boost::filesystem::file_size (files[i]));
-		fread (p, 1, this_time, f);
+		checked_fread (p, this_time, f, files[i]);
 		p += this_time;
  		to_do -= this_time;
 		fclose (f);
@@ -465,7 +465,7 @@ digest_head_tail (vector<boost::filesystem::path> files, boost::uintmax_t size)
 
 		boost::uintmax_t this_time = min (to_do, boost::filesystem::file_size (files[i]));
 		dcpomatic_fseek (f, -this_time, SEEK_END);
-		fread (p, 1, this_time, f);
+		checked_fread (p, this_time, f, files[i]);
 		p += this_time;
 		to_do -= this_time;
 		fclose (f);
@@ -782,3 +782,16 @@ increment_eyes (Eyes e)
 
 	return EYES_LEFT;
 }
+
+void
+checked_fread (void* ptr, size_t size, FILE* stream, boost::filesystem::path path)
+{
+	size_t N = fread (ptr, 1, size, stream);
+	if (N != size) {
+		if (ferror(stream)) {
+			throw FileError (String::compose("fread error %1", errno), path);
+		} else {
+			throw FileError ("Unexpected short read", path);
+		}
+	}
+}