Emulator: Enhance qemu_pipe.h to handle partial rw

Partial read and write happen and it is better to try again
unless there is some hard error. This is meant to fix some
flaky behavior of emulator pipe services, hopefully.

BUG: 35207286

manually tested this on emulator image.

(cherry picked from aosp f099dce4a622f2ece313abe71a422489704ee692)

Change-Id: I26a4560fa34e979939edcc882fcc5190202fe9f6

1 files changed, 10 insertions, 15 deletions

diff --git a/qemu_pipe/qemu_pipe.cpp b/qemu_pipe/qemu_pipe.cpp
index a4529deb8..ca3b79578 100644
--- a/qemu_pipe/qemu_pipe.cpp
+++ b/qemu_pipe/qemu_pipe.cpp
@@ -22,6 +22,10 @@
 #include <errno.h>
 #include <stdio.h>
 
+#include <android-base/file.h>
+
+using android::base::ReadFully;
+using android::base::WriteFully;
 
 // Define QEMU_PIPE_DEBUG if you want to print error messages when an error
 // occurs during pipe operations. The macro should simply take a printf-style
@@ -66,15 +70,10 @@ int qemu_pipe_open(const char* pipeName) {
 
     // Write the pipe name, *including* the trailing zero which is necessary.
     size_t pipeNameLen = strlen(pipeName);
-    ssize_t ret = TEMP_FAILURE_RETRY(write(fd, pipeName, pipeNameLen + 1U));
-    if (ret != (ssize_t)pipeNameLen + 1) {
+    if (!WriteFully(fd, pipeName, pipeNameLen + 1U)) {
         QEMU_PIPE_DEBUG("%s: Could not connect to %s pipe service: %s",
                         __FUNCTION__, pipeName, strerror(errno));
-        if (ret == 0) {
-            errno = ECONNRESET;
-        } else if (ret > 0) {
-            errno = EINVAL;
-        }
+        close(fd);
         return -1;
     }
     return fd;
@@ -86,13 +85,11 @@ int qemu_pipe_open(const char* pipeName) {
 int qemu_pipe_frame_send(int fd, const void* buff, size_t len) {
     char header[5];
     snprintf(header, sizeof(header), "%04zx", len);
-    ssize_t ret = TEMP_FAILURE_RETRY(write(fd, header, 4));
-    if (ret != 4) {
+    if (!WriteFully(fd, header, 4)) {
         QEMU_PIPE_DEBUG("Can't write qemud frame header: %s", strerror(errno));
         return -1;
     }
-    ret = TEMP_FAILURE_RETRY(write(fd, buff, len));
-    if (ret != (ssize_t)len) {
+    if (!WriteFully(fd, buff, len)) {
         QEMU_PIPE_DEBUG("Can't write qemud frame payload: %s", strerror(errno));
         return -1;
     }
@@ -106,8 +103,7 @@ int qemu_pipe_frame_send(int fd, const void* buff, size_t len) {
 // end-of-stream.
 int qemu_pipe_frame_recv(int fd, void* buff, size_t len) {
     char header[5];
-    ssize_t ret = TEMP_FAILURE_RETRY(read(fd, header, 4));
-    if (ret != 4) {
+    if (!ReadFully(fd, header, 4)) {
         QEMU_PIPE_DEBUG("Can't read qemud frame header: %s", strerror(errno));
         return -1;
     }
@@ -122,8 +118,7 @@ int qemu_pipe_frame_recv(int fd, void* buff, size_t len) {
                         len);
         return -1;
     }
-    ret = TEMP_FAILURE_RETRY(read(fd, buff, size));
-    if (ret != (ssize_t)size) {
+    if (!ReadFully(fd, buff, size)) {
         QEMU_PIPE_DEBUG("Could not read qemud frame payload: %s",
                         strerror(errno));
         return -1;