Migrate from android::String path functions to std::filesystem

Bug: 295394788
Test: m checkbuild
Change-Id: I7efdc32872d00c066b9a874d774e5ecdc5e53722
diff --git a/cmds/cmd/cmd.cpp b/cmds/cmd/cmd.cpp
index b727398..0ce7711 100644
--- a/cmds/cmd/cmd.cpp
+++ b/cmds/cmd/cmd.cpp
@@ -27,6 +27,7 @@
 #include <utils/Mutex.h>
 #include <utils/Vector.h>
 
+#include <filesystem>
 #include <getopt.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -69,10 +70,8 @@
     virtual int openFile(const String16& path, const String16& seLinuxContext,
             const String16& mode) {
         String8 path8(path);
-        char cwd[256];
-        getcwd(cwd, 256);
-        String8 fullPath(cwd);
-        fullPath.appendPath(path8);
+        auto fullPath = std::filesystem::current_path();
+        fullPath /= path8.c_str();
         if (!mActive) {
             mErrorLog << "Open attempt after active for: " << fullPath << endl;
             return -EPERM;