[runtime] Transition to new fdio functions

This should allow Dart to start targeting Fuchsia API level 28.

TEST=ci

Bug: b/434220174
Change-Id: Id55deb491122be85d9a5731be2c7571b0126dcd8
Cq-Include-Trybots: luci.dart.try:vm-fuchsia-release-arm64-try,vm-fuchsia-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/448260
Commit-Queue: Ben Konyi <[email protected]>
Reviewed-by: Ben Konyi <[email protected]>

Author: Breakthrough

runtime/bin/directory_fuchsia.cc

@@ -7,15 +7,14 @@
 
 #include "bin/directory.h"
 
-#include <dirent.h>              // NOLINT
-#include <errno.h>               // NOLINT
-#include <fcntl.h>               // NOLINT
-#include <lib/fdio/namespace.h>  // NOLINT
-#include <stdlib.h>              // NOLINT
-#include <string.h>              // NOLINT
-#include <sys/param.h>           // NOLINT
-#include <sys/stat.h>            // NOLINT
-#include <unistd.h>              // NOLINT
+#include <dirent.h>     // NOLINT
+#include <errno.h>      // NOLINT
+#include <fcntl.h>      // NOLINT
+#include <stdlib.h>     // NOLINT
+#include <string.h>     // NOLINT
+#include <sys/param.h>  // NOLINT
+#include <sys/stat.h>   // NOLINT
+#include <unistd.h>     // NOLINT
 
 #include "bin/crypto.h"
 #include "bin/dartutils.h"

runtime/bin/process_fuchsia.cc

@@ -586,24 +586,18 @@ class ProcessStarter {
     NamespaceScope ns(namespc_, path_);
     int pathfd = -1;
     zx_status_t status;
+    constexpr fuchsia::io::Flags kFlags =
+        fuchsia::io::PERM_READABLE | fuchsia::io::PERM_EXECUTABLE;
     if (ns.fd() == AT_FDCWD) {
-      status = fdio_open_fd(
-          ns.path(),
-          static_cast<uint32_t>(fuchsia::io::OpenFlags::RIGHT_READABLE |
-                                fuchsia::io::OpenFlags::RIGHT_EXECUTABLE),
-          &pathfd);
+      status = fdio_open3_fd(ns.path(), uint64_t{kFlags}, &pathfd);
     } else {
-      status = fdio_open_fd_at(
-          ns.fd(), ns.path(),
-          static_cast<uint32_t>(fuchsia::io::OpenFlags::RIGHT_READABLE |
-                                fuchsia::io::OpenFlags::RIGHT_EXECUTABLE),
-          &pathfd);
+      status = fdio_open3_fd_at(ns.fd(), ns.path(), uint64_t{kFlags}, &pathfd);
     }
     if (status != ZX_OK) {
       close(exit_pipe_fds[0]);
       close(exit_pipe_fds[1]);
       ReportStartError(
-          "Failed to load executable for process start (fdio_open_fd_at %s).",
+          "Failed to load executable for process start (fdio_open3_fd_at %s).",
           zx_status_get_string(status));
       return status;
     }

runtime/platform/utils.cc

@@ -306,10 +306,10 @@ void* Utils::LoadDynamicLibrary(const char* library_path,
   if (handle == nullptr) {
     // Fuchsia's search path is different.
     // https://fuchsia.dev/fuchsia-src/concepts/process/program_loading#zircons_standard_elf_dynamic_linker
-    fuchsia::io::Flags flags =
+    constexpr fuchsia::io::Flags kFlags =
         fuchsia::io::PERM_READABLE | fuchsia::io::PERM_EXECUTABLE;
     int fd = -1;
-    zx_status_t status = fdio_open3_fd(library_path, uint64_t{flags}, &fd);
+    zx_status_t status = fdio_open3_fd(library_path, uint64_t{kFlags}, &fd);
     if (status != ZX_OK) {
       *error = strdup(zx_status_get_string(status));
       return nullptr;