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

util/file/fd_io.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #include "util/file/fd_io.h"
 
 #include <unistd.h>
 
+#include "base/logging.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/posix/eintr_wrapper.h"
 
 namespace {
 
 struct ReadTraits {
   typedef void* VoidBufferType;
   typedef char* CharBufferType;
   static ssize_t Operate(int fd, CharBufferType buffer, size_t size) {
     return read(fd, buffer, size);
   }
@@ skipping 36 matching lines @@
 namespace crashpad {
 
 ssize_t ReadFD(int fd, void* buffer, size_t size) {
   return ReadOrWrite<ReadTraits>(fd, buffer, size);
 }
 
 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