libbinder: move interruptableReadOrWrite to new file

Moves interruptableReadOrWrite to a new RpcTransportUtils.h
file so it can be used by multiple transports.

Bug: 224644083
Test: m
Change-Id: Ife48519ab5c6a99d5fbbcd4ad9e6c3fe517dd0ba

3 files changed, 115 insertions, 86 deletions

diff --git a/libs/binder/FdTrigger.h b/libs/binder/FdTrigger.h
index 5c7102e22e..a25dc117f3 100644
--- a/libs/binder/FdTrigger.h
+++ b/libs/binder/FdTrigger.h
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+#pragma once
 
 #include <memory>
 
diff --git a/libs/binder/RpcTransportRaw.cpp b/libs/binder/RpcTransportRaw.cpp
index 7cc58cd776..51326f6346 100644
--- a/libs/binder/RpcTransportRaw.cpp
+++ b/libs/binder/RpcTransportRaw.cpp
@@ -24,6 +24,7 @@
 
 #include "FdTrigger.h"
 #include "RpcState.h"
+#include "RpcTransportUtils.h"
 
 namespace android {
 
@@ -55,90 +56,6 @@ public:
         return OK;
     }
 
-    template <typename SendOrReceive>
-    status_t interruptableReadOrWrite(
-            FdTrigger* fdTrigger, iovec* iovs, int niovs, SendOrReceive sendOrReceiveFun,
-            const char* funName, int16_t event,
-            const std::optional<android::base::function_ref<status_t()>>& altPoll) {
-        MAYBE_WAIT_IN_FLAKE_MODE;
-
-        if (niovs < 0) {
-            return BAD_VALUE;
-        }
-
-        // Since we didn't poll, we need to manually check to see if it was triggered. Otherwise, we
-        // may never know we should be shutting down.
-        if (fdTrigger->isTriggered()) {
-            return DEAD_OBJECT;
-        }
-
-        // If iovs has one or more empty vectors at the end and
-        // we somehow advance past all the preceding vectors and
-        // pass some or all of the empty ones to sendmsg/recvmsg,
-        // the call will return processSize == 0. In that case
-        // we should be returning OK but instead return DEAD_OBJECT.
-        // To avoid this problem, we make sure here that the last
-        // vector at iovs[niovs - 1] has a non-zero length.
-        while (niovs > 0 && iovs[niovs - 1].iov_len == 0) {
-            niovs--;
-        }
-        if (niovs == 0) {
-            // The vectors are all empty, so we have nothing to send.
-            return OK;
-        }
-
-        bool havePolled = false;
-        while (true) {
-            ssize_t processSize = sendOrReceiveFun(iovs, niovs);
-            if (processSize < 0) {
-                int savedErrno = errno;
-
-                // Still return the error on later passes, since it would expose
-                // a problem with polling
-                if (havePolled || (savedErrno != EAGAIN && savedErrno != EWOULDBLOCK)) {
-                    LOG_RPC_DETAIL("RpcTransport %s(): %s", funName, strerror(savedErrno));
-                    return -savedErrno;
-                }
-            } else if (processSize == 0) {
-                return DEAD_OBJECT;
-            } else {
-                while (processSize > 0 && niovs > 0) {
-                    auto& iov = iovs[0];
-                    if (static_cast<size_t>(processSize) < iov.iov_len) {
-                        // Advance the base of the current iovec
-                        iov.iov_base = reinterpret_cast<char*>(iov.iov_base) + processSize;
-                        iov.iov_len -= processSize;
-                        break;
-                    }
-
-                    // The current iovec was fully written
-                    processSize -= iov.iov_len;
-                    iovs++;
-                    niovs--;
-                }
-                if (niovs == 0) {
-                    LOG_ALWAYS_FATAL_IF(processSize > 0,
-                                        "Reached the end of iovecs "
-                                        "with %zd bytes remaining",
-                                        processSize);
-                    return OK;
-                }
-            }
-
-            if (altPoll) {
-                if (status_t status = (*altPoll)(); status != OK) return status;
-                if (fdTrigger->isTriggered()) {
-                    return DEAD_OBJECT;
-                }
-            } else {
-                if (status_t status = fdTrigger->triggerablePoll(mSocket.get(), event);
-                    status != OK)
-                    return status;
-                if (!havePolled) havePolled = true;
-            }
-        }
-    }
-
     status_t interruptableWriteFully(
             FdTrigger* fdTrigger, iovec* iovs, int niovs,
             const std::optional<android::base::function_ref<status_t()>>& altPoll,
@@ -198,7 +115,8 @@ public:
             };
             return TEMP_FAILURE_RETRY(sendmsg(mSocket.get(), &msg, MSG_NOSIGNAL));
         };
-        return interruptableReadOrWrite(fdTrigger, iovs, niovs, send, "sendmsg", POLLOUT, altPoll);
+        return interruptableReadOrWrite(mSocket.get(), fdTrigger, iovs, niovs, send, "sendmsg",
+                                        POLLOUT, altPoll);
     }
 
     status_t interruptableReadFully(
@@ -255,7 +173,8 @@ public:
             };
             return TEMP_FAILURE_RETRY(recvmsg(mSocket.get(), &msg, MSG_NOSIGNAL));
         };
-        return interruptableReadOrWrite(fdTrigger, iovs, niovs, recv, "recvmsg", POLLIN, altPoll);
+        return interruptableReadOrWrite(mSocket.get(), fdTrigger, iovs, niovs, recv, "recvmsg",
+                                        POLLIN, altPoll);
     }
 
 private:
diff --git a/libs/binder/RpcTransportUtils.h b/libs/binder/RpcTransportUtils.h
new file mode 100644
index 0000000000..00cb2af8c3
--- /dev/null
+++ b/libs/binder/RpcTransportUtils.h
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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.
+ */
+#pragma once
+
+#include <android-base/unique_fd.h>
+#include <poll.h>
+
+#include "FdTrigger.h"
+#include "RpcState.h"
+
+namespace android {
+
+template <typename SendOrReceive>
+status_t interruptableReadOrWrite(
+        int socketFd, FdTrigger* fdTrigger, iovec* iovs, int niovs, SendOrReceive sendOrReceiveFun,
+        const char* funName, int16_t event,
+        const std::optional<android::base::function_ref<status_t()>>& altPoll) {
+    MAYBE_WAIT_IN_FLAKE_MODE;
+
+    if (niovs < 0) {
+        return BAD_VALUE;
+    }
+
+    // Since we didn't poll, we need to manually check to see if it was triggered. Otherwise, we
+    // may never know we should be shutting down.
+    if (fdTrigger->isTriggered()) {
+        return DEAD_OBJECT;
+    }
+
+    // If iovs has one or more empty vectors at the end and
+    // we somehow advance past all the preceding vectors and
+    // pass some or all of the empty ones to sendmsg/recvmsg,
+    // the call will return processSize == 0. In that case
+    // we should be returning OK but instead return DEAD_OBJECT.
+    // To avoid this problem, we make sure here that the last
+    // vector at iovs[niovs - 1] has a non-zero length.
+    while (niovs > 0 && iovs[niovs - 1].iov_len == 0) {
+        niovs--;
+    }
+    if (niovs == 0) {
+        // The vectors are all empty, so we have nothing to send.
+        return OK;
+    }
+
+    bool havePolled = false;
+    while (true) {
+        ssize_t processSize = sendOrReceiveFun(iovs, niovs);
+        if (processSize < 0) {
+            int savedErrno = errno;
+
+            // Still return the error on later passes, since it would expose
+            // a problem with polling
+            if (havePolled || (savedErrno != EAGAIN && savedErrno != EWOULDBLOCK)) {
+                LOG_RPC_DETAIL("RpcTransport %s(): %s", funName, strerror(savedErrno));
+                return -savedErrno;
+            }
+        } else if (processSize == 0) {
+            return DEAD_OBJECT;
+        } else {
+            while (processSize > 0 && niovs > 0) {
+                auto& iov = iovs[0];
+                if (static_cast<size_t>(processSize) < iov.iov_len) {
+                    // Advance the base of the current iovec
+                    iov.iov_base = reinterpret_cast<char*>(iov.iov_base) + processSize;
+                    iov.iov_len -= processSize;
+                    break;
+                }
+
+                // The current iovec was fully written
+                processSize -= iov.iov_len;
+                iovs++;
+                niovs--;
+            }
+            if (niovs == 0) {
+                LOG_ALWAYS_FATAL_IF(processSize > 0,
+                                    "Reached the end of iovecs "
+                                    "with %zd bytes remaining",
+                                    processSize);
+                return OK;
+            }
+        }
+
+        if (altPoll) {
+            if (status_t status = (*altPoll)(); status != OK) return status;
+            if (fdTrigger->isTriggered()) {
+                return DEAD_OBJECT;
+            }
+        } else {
+            if (status_t status = fdTrigger->triggerablePoll(socketFd, event); status != OK)
+                return status;
+            if (!havePolled) havePolled = true;
+        }
+    }
+}
+
+} // namespace android