Add ugly CMP_F_TYPE() macro

[elogind.git] / src / shared / macro.h

diff --git a/src/shared/macro.h b/src/shared/macro.h
index 9bf81dc3cc541229bebe333d8d3ee31074ffe68b..f91f7de76956da0de546cf4bdba1b9c7c66650ca 100644 (file)
--- a/src/shared/macro.h
+++ b/src/shared/macro.h
@@ -264,6 +264,23 @@ do {                                                                    \
         }                                                               \
 } while(false)
 
+/* Remove this macro, when the kernel has f_type as unsigned int or long
+ * for every architecure. Currently some 64bit architecures (like s390x)
+ * have int in the kernel, but long in userspace for f_type, so glibc
+ * extends the int to long and carries over the sign. Negative numbers are
+ * caused by the 32bit magic constants in linux/magic.h stuffed into the
+ * signed int in the kernel and these negative numbers are extended to
+ * long, which cannot be simply compared to the magic constants anymore.
+ */
+#define CMP_F_TYPE(f, c)                                                \
+        __extension__ ({                                                \
+                        __SWORD_TYPE _f = (f);                          \
+                        const __SWORD_TYPE _c = (c);                    \
+                        const int _c32 = (c);                           \
+                        (_f == _c || _f == _c32 );                      \
+                })
+
+
 /* Returns the number of chars needed to format variables of the
  * specified type as a decimal string. Adds in extra space for a
  * negative '-' prefix. */