Add and use CheckedReadFD(), CheckedWriteFD(), and CheckedReadFDAtEOF()

util/file/fd_io.cc

Index: util/file/fd_io.cc
diff --git a/util/file/fd_io.cc b/util/file/fd_io.cc
index 942588002020cd1e7b43af45a015d9c4e8fd065e..46a3634fc7cda80e08ca6a83ec104170d6936b15 100644
--- a/util/file/fd_io.cc
+++ b/util/file/fd_io.cc
@@ -16,6 +16,8 @@
 
 #include <unistd.h>
 
+#include "base/logging.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/posix/eintr_wrapper.h"
 
 namespace {
@@ -72,4 +74,34 @@ ssize_t WriteFD(int fd, const void* buffer, size_t size) {
   return ReadOrWrite<WriteTraits>(fd, buffer, size);
 }
 
+void CheckedReadFD(int fd, void* buffer, size_t size) {
+  ssize_t expect = base::checked_cast<ssize_t>(size);
+  ssize_t rv = ReadFD(fd, buffer, size);
+  if (rv < 0) {
+    PCHECK(rv == expect) << "read";
+  } else {
+    CHECK_EQ(rv, expect) << "read";
+  }
+}
+
+void CheckedWriteFD(int fd, const void* buffer, size_t size) {
+  ssize_t expect = base::checked_cast<ssize_t>(size);
+  ssize_t rv = WriteFD(fd, buffer, size);
+  if (rv < 0) {
+    PCHECK(rv == expect) << "write";
+  } else {
+    CHECK_EQ(rv, expect) << "write";
+  }
+}
+
+void CheckedReadFDAtEOF(int fd) {
+  char c;
+  ssize_t rv = ReadFD(fd, &c, 1);
+  if (rv < 0) {
+    PCHECK(rv == 0) << "read";
+  } else {
+    CHECK_EQ(rv, 0) << "read";
+  }
+}
+
 }  // namespace crashpad