adb: move towards using unique_fd.

Bug: http://b/79786774
Test: treehugger
Change-Id: Ib5a684bba88e87e1aad9da452dcdd5edd11f18f4

adb/adb.cpp

@@ -885,9 +885,8 @@ int launch_server(const std::string& socket_spec) {
     }
 #else /* !defined(_WIN32) */
     // set up a pipe so the child can tell us when it is ready.
-    // fd[0] will be parent's end, and the child will write on fd[1]
-    int fd[2];
-    if (pipe(fd)) {
+    unique_fd pipe_read, pipe_write;
+    if (!Pipe(&pipe_read, &pipe_write)) {
         fprintf(stderr, "pipe failed in launch_server, errno: %d\n", errno);
         return -1;
     }
@@ -899,11 +898,10 @@ int launch_server(const std::string& socket_spec) {
 
     if (pid == 0) {
         // child side of the fork
-
-        adb_close(fd[0]);
+        pipe_read.reset();
 
         char reply_fd[30];
-        snprintf(reply_fd, sizeof(reply_fd), "%d", fd[1]);
+        snprintf(reply_fd, sizeof(reply_fd), "%d", pipe_write.get());
         // child process
         int result = execl(path.c_str(), "adb", "-L", socket_spec.c_str(), "fork-server", "server",
                            "--reply-fd", reply_fd, NULL);
@@ -913,10 +911,10 @@ int launch_server(const std::string& socket_spec) {
         // parent side of the fork
         char temp[3] = {};
         // wait for the "OK\n" message
-        adb_close(fd[1]);
-        int ret = adb_read(fd[0], temp, 3);
+        pipe_write.reset();
+        int ret = adb_read(pipe_read.get(), temp, 3);
         int saved_errno = errno;
-        adb_close(fd[0]);
+        pipe_read.reset();
         if (ret < 0) {
             fprintf(stderr, "could not read ok from ADB Server, errno = %d\n", saved_errno);
             return -1;

adb/adb_unique_fd.h

@@ -16,6 +16,8 @@
 
 #pragma once
 
+#include <unistd.h>
+
 #include <android-base/unique_fd.h>
 
 // Helper to automatically close an FD when it goes out of scope.
@@ -24,3 +26,15 @@ struct AdbCloser {
 };
 
 using unique_fd = android::base::unique_fd_impl<AdbCloser>;
+
+#if !defined(_WIN32)
+inline bool Pipe(unique_fd* read, unique_fd* write) {
+    int pipefd[2];
+    if (pipe(pipefd) != 0) {
+        return false;
+    }
+    read->reset(pipefd[0]);
+    write->reset(pipefd[1]);
+    return true;
+}
+#endif