test: specialize OOM check for AIX

Assumption that if memory can be malloc()ed it can be used is not true on AIX. Later access of the allocated pages can trigger SIGKILL if there are insufficient VM pages. Use psdanger() to better estimate available memory. Fixes: nodejs/build#1849 More info: - https://www.ibm.com/support/knowledgecenter/en/ssw_aix_71/generalprogramming/sys_mem_alloc.html - https://www.ibm.com/support/knowledgecenter/en/ssw_aix_71/p_bostechref/psdanger.html Related to: - nodejs/build#1820 (comment) - #28469 - #28516 PR-URL: #28857 Backport-PR-URL: #29599 Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com> Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com> Reviewed-By: Rich Trott <rtrott@gmail.com>
nodejs · andrewhughes101 · Jun 28, 2019 · Jul 2, 2019 · Jul 8, 2019 · Jul 24, 2019
commit 3c5a25f4e789692bd18d244fbbf451621bfd7e14
diff --git a/test/addons/addon.status b/test/addons/addon.status
@@ -3,17 +3,3 @@ prefix addons
 [true] # This section applies to all platforms
 
 [$system==aix]
-# https://github.com/nodejs/build/issues/1820#issuecomment-505998851
-# https://github.com/nodejs/node/pull/28469
-# https://github.com/nodejs/node/pull/28516
-stringbytes-external-exceed-max/test-stringbytes-external-exceed-max.js: SKIP
-
-# https://github.com/nodejs/node/pull/28516
-stringbytes-external-exceed-max/test-stringbytes-external-at-max: SKIP
-stringbytes-external-exceed-max/test-stringbytes-external-exceed-max-by-1-ascii: SKIP
-stringbytes-external-exceed-max/test-stringbytes-external-exceed-max-by-1-base64: SKIP
-stringbytes-external-exceed-max/test-stringbytes-external-exceed-max-by-1-binary: SKIP
-stringbytes-external-exceed-max/test-stringbytes-external-exceed-max-by-1-hex: SKIP
-stringbytes-external-exceed-max/test-stringbytes-external-exceed-max-by-1-utf8: SKIP
-stringbytes-external-exceed-max/test-stringbytes-external-exceed-max-by-2: SKIP
-stringbytes-external-exceed-max/test-stringbytes-external-exceed-max: SKIP
diff --git a/test/addons/stringbytes-external-exceed-max/binding.cc b/test/addons/stringbytes-external-exceed-max/binding.cc
@@ -2,12 +2,42 @@
 #include <node.h>
 #include <v8.h>
 
+#ifdef _AIX
+// AIX allows over-allocation, and will SIGKILL when the allocated pages are
+// used if there is not enough VM. Check for available space until
+// out-of-memory.  Don't allow more then some (large) proportion of it to be
+// used for the test strings, so Node & V8 have some space for allocations.
+#include <signal.h>
+#include <sys/vminfo.h>
+
+static void* Allowed(size_t size) {
+  blkcnt_t allowedBlocks = psdanger(SIGKILL);
+
+  if (allowedBlocks < 1) {
+    // Already OOM
+    return nullptr;
+  }
+  const size_t BYTES_PER_BLOCK = 512;
+  size_t allowed = (allowedBlocks * BYTES_PER_BLOCK * 4) / 5;
+  if (size < allowed) {
+    return malloc(size);
+  }
+  return nullptr;
+}
+#else
+// Other systems also allow over-allocation, but this malloc-and-free approach
+// seems to be working for them.
+static void* Allowed(size_t size) {
+  return malloc(size);
+}
+#endif  // _AIX
+
 void EnsureAllocation(const v8::FunctionCallbackInfo<v8::Value> &args) {
   v8::Isolate* isolate = args.GetIsolate();
   uintptr_t size = args[0]->IntegerValue();
   v8::Local<v8::Boolean> success;
 
-  void* buffer = malloc(size);
+  void* buffer = Allowed(size);
   if (buffer) {
     success = v8::Boolean::New(isolate, true);
     free(buffer);