Linux: Fix a bunch of clang errors from not handling return values.

Review URL: https://breakpad.appspot.com/421002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@995 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/client/linux/crash_generation/crash_generation_client.cc

@@ -35,6 +35,7 @@
 
 #include "client/linux/crash_generation/crash_generation_client.h"
 #include "common/linux/eintr_wrapper.h"
+#include "common/linux/ignore_ret.h"
 #include "common/linux/linux_libc_support.h"
 #include "third_party/lss/linux_syscall_support.h"
 
@@ -67,12 +68,14 @@ CrashGenerationClient::RequestDump(const void* blob, size_t blob_size)
   int* p = reinterpret_cast<int*>(CMSG_DATA(hdr));
   *p = fds[1];
 
-  HANDLE_EINTR(sys_sendmsg(server_fd_, &msg, 0));
+  ssize_t ret = HANDLE_EINTR(sys_sendmsg(server_fd_, &msg, 0));
   sys_close(fds[1]);
+  if (ret <= 0)
+    return false;
 
   // wait for an ACK from the server
   char b;
-  HANDLE_EINTR(sys_read(fds[0], &b, 1));
+  IGNORE_RET(HANDLE_EINTR(sys_read(fds[0], &b, 1)));
 
   return true;
 }

src/client/linux/handler/exception_handler_unittest.cc

@@ -43,6 +43,7 @@
 #include "client/linux/minidump_writer/minidump_writer.h"
 #include "common/linux/eintr_wrapper.h"
 #include "common/linux/file_id.h"
+#include "common/linux/ignore_ret.h"
 #include "common/linux/linux_libc_support.h"
 #include "common/tests/auto_tempdir.h"
 #include "common/using_std_string.h"
@@ -88,8 +89,8 @@ static bool DoneCallback(const char* dump_path,
 
   int fd = (intptr_t) context;
   uint32_t len = my_strlen(minidump_id);
-  HANDLE_EINTR(sys_write(fd, &len, sizeof(len)));
-  HANDLE_EINTR(sys_write(fd, minidump_id, len));
+  IGNORE_RET(HANDLE_EINTR(sys_write(fd, &len, sizeof(len))));
+  IGNORE_RET(HANDLE_EINTR(sys_write(fd, minidump_id, len)));
   sys_close(fd);
 
   return true;
@@ -703,11 +704,13 @@ CrashHandler(const void* crash_context, size_t crash_context_size,
   cred->gid = getgid();
   cred->pid = getpid();
 
-  HANDLE_EINTR(sys_sendmsg(fd, &msg, 0));
+  ssize_t ret = HANDLE_EINTR(sys_sendmsg(fd, &msg, 0));
   sys_close(fds[1]);
+  if (ret <= 0)
+    return false;
 
   char b;
-  HANDLE_EINTR(sys_read(fds[0], &b, 1));
+  IGNORE_RET(HANDLE_EINTR(sys_read(fds[0], &b, 1)));
 
   return true;
 }
@@ -772,7 +775,7 @@ TEST(ExceptionHandlerTest, ExternalDumper) {
   ASSERT_TRUE(WriteMinidump(templ.c_str(), crashing_pid, context,
                             kCrashContextSize));
   static const char b = 0;
-  HANDLE_EINTR(write(signal_fd, &b, 1));
+  ASSERT_EQ(1U, (HANDLE_EINTR(write(signal_fd, &b, 1))));
   ASSERT_EQ(close(signal_fd), 0);
 
   int status;

src/client/linux/minidump_writer/linux_ptrace_dumper_unittest.cc

@@ -52,6 +52,7 @@
 #include "client/linux/minidump_writer/minidump_writer_unittest_utils.h"
 #include "common/linux/eintr_wrapper.h"
 #include "common/linux/file_id.h"
+#include "common/linux/ignore_ret.h"
 #include "common/linux/safe_readlink.h"
 #include "common/memory.h"
 #include "common/using_std_string.h"
@@ -343,7 +344,7 @@ TEST(LinuxPtraceDumperTest, LinuxGateMappingIDChild) {
     close(fds[1]);
     // Now wait forever for the parent.
     char b;
-    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
     close(fds[0]);
     syscall(__NR_exit);
   }
@@ -395,7 +396,7 @@ TEST(LinuxPtraceDumperTest, FileIDsMatch) {
     close(fds[1]);
     // Now wait forever for the parent.
     char b;
-    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
     close(fds[0]);
     syscall(__NR_exit);
   }

src/client/linux/minidump_writer/minidump_writer_unittest.cc

@@ -44,6 +44,7 @@
 #include "client/linux/minidump_writer/minidump_writer_unittest_utils.h"
 #include "common/linux/eintr_wrapper.h"
 #include "common/linux/file_id.h"
+#include "common/linux/ignore_ret.h"
 #include "common/linux/safe_readlink.h"
 #include "common/tests/auto_tempdir.h"
 #include "common/using_std_string.h"
@@ -68,7 +69,7 @@ TEST(MinidumpWriterTest, Setup) {
   if (child == 0) {
     close(fds[1]);
     char b;
-    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
     close(fds[0]);
     syscall(__NR_exit);
   }
@@ -132,7 +133,7 @@ TEST(MinidumpWriterTest, MappingInfo) {
   if (child == 0) {
     close(fds[1]);
     char b;
-    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
     close(fds[0]);
     syscall(__NR_exit);
   }
@@ -237,7 +238,7 @@ TEST(MinidumpWriterTest, MappingInfoContained) {
   if (child == 0) {
     close(fds[1]);
     char b;
-    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
     close(fds[0]);
     syscall(__NR_exit);
   }

src/common/linux/eintr_wrapper.h

@@ -44,4 +44,4 @@
   __eintr_result__;\
 })
 
-#endif // ifndef COMMON_LINUX_EINTR_WRAPPER_H_
+#endif  // COMMON_LINUX_EINTR_WRAPPER_H_

src/common/linux/ignore_ret.h

@@ -0,0 +1,40 @@
+// Copyright (c) 2012 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef COMMON_LINUX_IGNORE_RET_H_
+#define COMMON_LINUX_IGNORE_RET_H_
+
+// Some compilers are prone to warn about unused return values. In cases where
+// either a) the call cannot fail, or b) there is nothing that can be done when
+// the call fails, IGNORE_RET() can be used to mark the return code as ignored.
+// This avoids spurious compiler warnings.
+
+#define IGNORE_RET(x) do { if (x); } while (0)
+
+#endif  // COMMON_LINUX_IGNORE_RET_H_