From 3dcfa3fb1cec36b21ad026c618c85790a2353f72 Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Tue, 23 Aug 2016 12:50:00 -0700
Subject: [PATCH] Most accept/accept4 calls in system/core don't actually want
 the remote address.

So don't write the extra code for it or waste the kernel's time
copying it around.

Change-Id: I93de64064c2d4fe58ba5b5322cfa69bf31a76dad
---
 adb/socket_test.cpp                |  5 +----
 debuggerd/debuggerd.cpp            |  6 +-----
 init/property_service.cpp          | 17 +++++++----------
 libsysutils/src/SocketListener.cpp | 11 +----------
 lmkd/lmkd.c                        |  6 +-----
 5 files changed, 11 insertions(+), 34 deletions(-)

diff --git a/adb/socket_test.cpp b/adb/socket_test.cpp
index d2ce2d875..2bb01a382 100644
--- a/adb/socket_test.cpp
+++ b/adb/socket_test.cpp
@@ -254,10 +254,7 @@ TEST_F(LocalSocketTest, close_socket_in_CLOSE_WAIT_state) {
     ASSERT_TRUE(adb_thread_create(reinterpret_cast<void (*)(void*)>(ClientThreadFunc), nullptr,
                                   &client_thread));
 
-    struct sockaddr addr;
-    socklen_t alen;
-    alen = sizeof(addr);
-    int accept_fd = adb_socket_accept(listen_fd, &addr, &alen);
+    int accept_fd = adb_socket_accept(listen_fd, nullptr, nullptr);
     ASSERT_GE(accept_fd, 0);
     CloseRdHupSocketArg arg;
     arg.socket_fd = accept_fd;
diff --git a/debuggerd/debuggerd.cpp b/debuggerd/debuggerd.cpp
index c578d658b..5550bc07d 100644
--- a/debuggerd/debuggerd.cpp
+++ b/debuggerd/debuggerd.cpp
@@ -821,12 +821,8 @@ static int do_server() {
   ALOGI("debuggerd: starting\n");
 
   for (;;) {
-    sockaddr_storage ss;
-    sockaddr* addrp = reinterpret_cast<sockaddr*>(&ss);
-    socklen_t alen = sizeof(ss);
-
     ALOGV("waiting for connection\n");
-    int fd = accept4(s, addrp, &alen, SOCK_CLOEXEC | SOCK_NONBLOCK);
+    int fd = accept4(s, nullptr, nullptr, SOCK_CLOEXEC | SOCK_NONBLOCK);
     if (fd == -1) {
       ALOGE("accept failed: %s\n", strerror(errno));
       continue;
diff --git a/init/property_service.cpp b/init/property_service.cpp
index e2e1b16fc..9e1373312 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -227,32 +227,29 @@ int property_set(const char* name, const char* value) {
 static void handle_property_set_fd()
 {
     prop_msg msg;
-    int s;
     int r;
-    struct ucred cr;
-    struct sockaddr_un addr;
-    socklen_t addr_size = sizeof(addr);
-    socklen_t cr_size = sizeof(cr);
     char * source_ctx = NULL;
-    struct pollfd ufds[1];
-    const int timeout_ms = 2 * 1000;  /* Default 2 sec timeout for caller to send property. */
-    int nr;
 
-    if ((s = accept(property_set_fd, (struct sockaddr *) &addr, &addr_size)) < 0) {
+    int s = accept(property_set_fd, nullptr, nullptr);
+    if (s == -1) {
         return;
     }
 
     /* Check socket options here */
+    struct ucred cr;
+    socklen_t cr_size = sizeof(cr);
     if (getsockopt(s, SOL_SOCKET, SO_PEERCRED, &cr, &cr_size) < 0) {
         close(s);
         PLOG(ERROR) << "Unable to receive socket options";
         return;
     }
 
+    static constexpr int timeout_ms = 2 * 1000;  /* Default 2 sec timeout for caller to send property. */
+    struct pollfd ufds[1];
     ufds[0].fd = s;
     ufds[0].events = POLLIN;
     ufds[0].revents = 0;
-    nr = TEMP_FAILURE_RETRY(poll(ufds, 1, timeout_ms));
+    int nr = TEMP_FAILURE_RETRY(poll(ufds, 1, timeout_ms));
     if (nr == 0) {
         LOG(ERROR) << "sys_prop: timeout waiting for uid " << cr.uid << " to send property message.";
         close(s);
diff --git a/libsysutils/src/SocketListener.cpp b/libsysutils/src/SocketListener.cpp
index 4d602a6aa..608abaea5 100644
--- a/libsysutils/src/SocketListener.cpp
+++ b/libsysutils/src/SocketListener.cpp
@@ -199,16 +199,7 @@ void SocketListener::runListener() {
             continue;
         }
         if (mListen && FD_ISSET(mSock, &read_fds)) {
-            sockaddr_storage ss;
-            sockaddr* addrp = reinterpret_cast<sockaddr*>(&ss);
-            socklen_t alen;
-            int c;
-
-            do {
-                alen = sizeof(ss);
-                c = accept4(mSock, addrp, &alen, SOCK_CLOEXEC);
-                SLOGV("%s got %d from accept", mSocketName, c);
-            } while (c < 0 && errno == EINTR);
+            int c = TEMP_FAILURE_RETRY(accept4(mSock, nullptr, nullptr, SOCK_CLOEXEC));
             if (c < 0) {
                 SLOGE("accept failed (%s)", strerror(errno));
                 sleep(1);
diff --git a/lmkd/lmkd.c b/lmkd/lmkd.c
index 37fbdb88d..733b7845d 100644
--- a/lmkd/lmkd.c
+++ b/lmkd/lmkd.c
@@ -410,9 +410,6 @@ static void ctrl_data_handler(uint32_t events) {
 }
 
 static void ctrl_connect_handler(uint32_t events __unused) {
-    struct sockaddr_storage ss;
-    struct sockaddr *addrp = (struct sockaddr *)&ss;
-    socklen_t alen;
     struct epoll_event epev;
 
     if (ctrl_dfd >= 0) {
@@ -420,8 +417,7 @@ static void ctrl_connect_handler(uint32_t events __unused) {
         ctrl_dfd_reopened = 1;
     }
 
-    alen = sizeof(ss);
-    ctrl_dfd = accept(ctrl_lfd, addrp, &alen);
+    ctrl_dfd = accept(ctrl_lfd, NULL, NULL);
 
     if (ctrl_dfd < 0) {
         ALOGE("lmkd control socket accept failed; errno=%d", errno);