Minimum port of `SysResource.h`

Reviewed By: yfeldblum

Differential Revision: D27260808

fbshipit-source-id: b15bcfea70f0ad5d92df3b1143ef417eb2b4adf9

folly/portability/SysResource.cpp

@@ -17,6 +17,7 @@
 #include <folly/portability/SysResource.h>
 
 #include <cerrno>
+#include <cstring>
 
 #ifdef _WIN32
 #include <folly/portability/Windows.h>
@@ -103,4 +104,41 @@ int setpriority(int which, int who, int value) {
   return 0;
 }
 }
+
+#elif defined(__XROS__)
+
+#include <xr/thread.h> // @manual
+
+extern "C" {
+
+int getrlimit(int type, rlimit* dst) {
+  if (type == RLIMIT_STACK) {
+    // NOTE: This limit is a conservative estimate.
+    dst->rlim_cur = c_xr_thread_default_stack_size;
+    dst->rlim_max = c_xr_thread_default_stack_size;
+    return 0;
+  }
+  return -1;
+}
+
+int getrusage(int /* who */, rusage* usage) {
+  std::memset(usage, 0, sizeof(rusage));
+  return 0;
+}
+
+int setrlimit(int /* type */, rlimit* /* src */) {
+  return 0;
+}
+
+int getpriority(int /* which */, int /* who */) {
+  // 20 is the default `nice` priority, report it.
+  return 20;
+}
+
+int setpriority(int /* which */, int /* who */, int /* value */) {
+  return -1;
+}
+
+}
+
 #endif

folly/portability/SysResource.h

@@ -16,7 +16,7 @@
 
 #pragma once
 
-#ifndef _WIN32
+#if !defined(_WIN32) && !defined(__XROS__)
 #include <sys/resource.h>
 #else
 #include <cstdint>