1 files changed, 43 insertions, 0 deletions
diff --git a/extras/multipath-tools/multipathd/sg_include.h b/extras/multipath-tools/multipathd/sg_include.h
new file mode 100644
index 0000000000..460506826e
--- /dev/null
+++ b/extras/multipath-tools/multipathd/sg_include.h
@@ -0,0 +1,43 @@
+#ifdef SG_KERNEL_INCLUDES
+  #define __user
+  typedef unsigned char u8;
+  #include "/usr/src/linux/include/scsi/sg.h"
+  #include "/usr/src/linux/include/scsi/scsi.h"
+#else
+  #ifdef SG_TRICK_GNU_INCLUDES
+    #include <linux/../scsi/sg.h>
+    #include <linux/../scsi/scsi.h>
+  #else
+    #include <scsi/sg.h>
+  #endif
+#endif
+
+/*
+  Getting the correct include files for the sg interface can be an ordeal.
+  In a perfect world, one would just write:
+    #include <scsi/sg.h>
+    #include <scsi/scsi.h>
+  This would include the files found in the /usr/include/scsi directory.
+  Those files are maintained with the GNU library which may or may not
+  agree with the kernel and version of sg driver that is running. Any
+  many cases this will not matter. However in some it might, for example
+  glibc 2.1's include files match the sg driver found in the lk 2.2
+  series. Hence if glibc 2.1 is used with lk 2.4 then the additional
+  sg v3 interface will not be visible.
+  If this is a problem then defining SG_KERNEL_INCLUDES will access the
+  kernel supplied header files (assuming they are in the normal place).
+  The GNU library maintainers and various kernel people don't like
+  this approach (but it does work).
+  The technique selected by defining SG_TRICK_GNU_INCLUDES worked (and
+  was used) prior to glibc 2.2 . Prior to that version /usr/include/linux
+  was a symbolic link to /usr/src/linux/include/linux .
+
+  There are other approaches if this include "mixup" causes pain. These
+  would involve include files being copied or symbolic links being
+  introduced.
+
+  Sorry about the inconvenience. Typically neither SG_KERNEL_INCLUDES
+  nor SG_TRICK_GNU_INCLUDES is defined.
+
+  dpg 20010415, 20030522
+*/