Bug 1001842 part 1: record the umask in NS_InitXPCOM2 and expose it to JS via nsSystemInfo. r=bsmedberg

xpcom/base/nsSystemInfo.cpp

@@ -40,6 +40,13 @@ NS_EXPORT int android_sdk_version;
 }
 #endif
 
+// Slot for NS_InitXPCOM2 to pass information to nsSystemInfo::Init.
+// Only set to nonzero (potentially) if XP_UNIX.  On such systems, the
+// system call to discover the appropriate value is not thread-safe,
+// so we must call it before going multithreaded, but nsSystemInfo::Init
+// only happens well after that point.
+uint32_t nsSystemInfo::gUserUmask = 0;
+
 #if defined(XP_WIN)
 namespace {
 nsresult GetHDDInfo(const char* aSpecialDirName, nsAutoCString& aModel,
@@ -198,6 +205,7 @@ nsSystemInfo::Init()
     SetInt32Property(NS_LITERAL_STRING("memmapalign"), PR_GetMemMapAlignment());
     SetInt32Property(NS_LITERAL_STRING("cpucount"), PR_GetNumberOfProcessors());
     SetUint64Property(NS_LITERAL_STRING("memsize"), PR_GetPhysicalMemorySize());
+    SetUint32Property(NS_LITERAL_STRING("umask"), nsSystemInfo::gUserUmask);
 
     for (uint32_t i = 0; i < ArrayLength(cpuPropItems); i++) {
         rv = SetPropertyAsBool(NS_ConvertASCIItoUTF16(cpuPropItems[i].name),
@@ -306,6 +314,19 @@ nsSystemInfo::SetInt32Property(const nsAString &aPropertyName,
   }
 }
 
+void
+nsSystemInfo::SetUint32Property(const nsAString &aPropertyName,
+                                const uint32_t aValue)
+{
+  // Only one property is currently set via this function.
+  // It may legitimately be zero.
+#ifdef DEBUG
+  nsresult rv =
+#endif
+    SetPropertyAsUint32(aPropertyName, aValue);
+  NS_WARN_IF_FALSE(NS_SUCCEEDED(rv), "Unable to set property");
+}
+
 void
 nsSystemInfo::SetUint64Property(const nsAString &aPropertyName,
                                 const uint64_t aValue)

xpcom/base/nsSystemInfo.h

@@ -14,9 +14,15 @@ public:
 
     nsresult Init();
 
+    // Slot for NS_InitXPCOM2 to pass information to nsSystemInfo::Init.
+    // See comments above the variable definition and in NS_InitXPCOM2.
+    static uint32_t gUserUmask;
+
 protected:
     void SetInt32Property(const nsAString &aPropertyName,
                           const int32_t aValue);
+    void SetUint32Property(const nsAString &aPropertyName,
+                           const uint32_t aValue);
     void SetUint64Property(const nsAString &aPropertyName,
                            const uint64_t aValue);
 

xpcom/build/nsXPComInit.cpp

@@ -461,6 +461,17 @@ NS_InitXPCOM2(nsIServiceManager* *result,
     // chance to start up, because the initialization is not thread-safe.
     mozilla::AvailableMemoryTracker::Init();
 
+#ifdef XP_UNIX
+    // Discover the current value of the umask, and save it where
+    // nsSystemInfo::Init can retrieve it when necessary.  There is no way
+    // to read the umask without changing it, and the setting is process-
+    // global, so this must be done while we are still single-threaded; the
+    // nsSystemInfo object is typically created much later, when some piece
+    // of chrome JS wants it.  The system call is specified as unable to fail.
+    nsSystemInfo::gUserUmask = ::umask(0777);
+    ::umask(nsSystemInfo::gUserUmask);
+#endif
+
     NS_LogInit();
 
     // Set up chromium libs

xpcom/tests/unit/test_systemInfo.js

@@ -13,4 +13,8 @@ function run_test() {
     let value = sysInfo.getProperty(aPropertyName);
     do_check_true(!!value);
   });
+
+  // This property must exist, but its value might be zero.
+  print("Testing property: umask")
+  do_check_eq(typeof sysInfo.getProperty("umask"), "number");
 }