avoid including header files directly

The kernel warns against including header files directly. For good
reason: our previous approach (just -I$KERNEL/include) caused all
kinds of files to be included that should have come from /usr/include
instead.

This patch rewrites the Makfile so that the (few) needed headers are
copied into the liblitmus src tree before compiling the library. This
avoids having to specify the kernel include directories with -I, and
also makes it easier to link against liblitmus (external applications
do not need to know where the kernel is).

Finally, this allows us to enable -Werror.

3 files changed, 50 insertions, 15 deletions

diff --git a/Makefile b/Makefile
index 5a86b33..62bcf4e 100644
--- a/Makefile
+++ b/Makefile
@@ -19,9 +19,8 @@ LITMUS_KERNEL ?= ../litmus2010
 # Internal configuration.
 
 # compiler flags
-flags-debug    = -Wall -g -Wdeclaration-after-statement
+flags-debug    = -Wall -Werror -g -Wdeclaration-after-statement
 flags-api      = -D_XOPEN_SOURCE=600 -D_GNU_SOURCE
-flags-link-rt  = -static
 
 # architecture-specific flags
 flags-i386     = -m32
@@ -36,13 +35,17 @@ include-sparc64  = sparc
 # default: the arch name
 include-${ARCH} ?= ${ARCH}
 
+# name of the file(s) that holds the actual system call numbers
+unistd-i386      = unistd.h unistd_32.h
+unistd-x86_64    = unistd.h unistd_64.h
+# default: unistd.h
+unistd-${ARCH}  ?= unistd.h
+
 # where to find header files
-headers = -Iinclude \
-        -I${LITMUS_KERNEL}/include/ \
-        -I${LITMUS_KERNEL}/arch/${include-${ARCH}}/include
+headers = -Iinclude -Iarch/${include-${ARCH}}/include
 
 # combine options
-CPPFLAGS = ${flags-api} ${flags-${ARCH}} ${headers}
+CPPFLAGS = ${flags-api} ${flags-${ARCH}} -DARCH=${ARCH} ${headers}
 CFLAGS   = ${flags-debug}
 LDFLAGS  = ${flags-${ARCH}}
 
@@ -78,6 +81,7 @@ dump-config:
                 LITMUS_KERNEL "${LITMUS_KERNEL}" \
                 CROSS_COMPILE "${CROSS_COMPILE}" \
                 headers "${headers}" \
+                "kernel headers" "${imported-headers}" \
                 CFLAGS "${CFLAGS}" \
                 LDFLAGS "${LDFLAGS}" \
                 CPPFLAGS "${CPPFLAGS}" \
@@ -90,7 +94,35 @@ dump-config:
 clean:
         rm -f ${rt-apps}
         rm -f *.o *.d *.a test_catalog.inc
+        rm -f ${imported-headers}
+
+# ##############################################################################
+# Kernel headers.
+# The kernel does not like being #included directly, so let's
+# copy out the parts that we need.
+
+# Litmus headers
+include/litmus/%.h: ${LITMUS_KERNEL}/include/litmus/%.h
+        @mkdir -p ${dir $@}
+        cp $< $@
+
+# asm headers
+arch/${include-${ARCH}}/include/asm/%.h: \
+        ${LITMUS_KERNEL}/arch/${include-${ARCH}}/include/asm/%.h
+        @mkdir -p ${dir $@}
+        cp $< $@
+
+litmus-headers = include/litmus/rt_param.h include/litmus/unistd_32.h \
+        include/litmus/unistd_64.h
+
+unistd-headers = \
+  $(foreach file,${unistd-${ARCH}},arch/${include-${ARCH}}/include/asm/$(file))
+
+
+imported-headers = ${litmus-headers} ${unistd-headers}
 
+# Let's not copy these twice.
+.SECONDARY: ${imported-headers}
 
 # ##############################################################################
 # liblitmus
@@ -159,8 +191,8 @@ vpath %.c bin/ src/ tests/
 
 obj-all = ${sort ${foreach target,${all},${obj-${target}}}}
 
-# rule to generate dependency files (straight from make manual)
-%.d: %.c
+# rule to generate dependency files
+%.d: %.c ${imported-headers}
         @set -e; rm -f $@; \
                 $(CC) -MM $(CPPFLAGS) $< > $@.$$$$; \
                 sed 's,\($*\)\.o[ :]*,\1.o $@ : ,g' < $@.$$$$ > $@; \
diff --git a/include/litmus.h b/include/litmus.h
index b798c92..c4c4129 100644
--- a/include/litmus.h
+++ b/include/litmus.h
@@ -5,13 +5,13 @@
 extern "C" {
 #endif
 
+#include <sys/types.h>
+
 /* Include kernel header.
  * This is required for the rt_param
  * and control_page structures.
  */
-#include <litmus/rt_param.h>
-
-#include <sys/types.h>
+#include "litmus/rt_param.h"
 
 #include "cycles.h" /* for null_call() */
 
diff --git a/src/syscalls.c b/src/syscalls.c
index 77a6277..c738ac4 100644
--- a/src/syscalls.c
+++ b/src/syscalls.c
@@ -1,13 +1,16 @@
 /* To get syscall() we need to define _GNU_SOURCE
  * in modern glibc versions.
  */
+
+/* imported from the kernel source tree */
+#include "asm/unistd.h"
+
+/* for syscall() */
 #include <unistd.h>
-#include <linux/unistd.h>
-#include <sys/types.h>
 
-#include "litmus.h"
+//#include <sys/types.h>
 
-struct np_flag;
+#include "litmus.h"
 
 /*      Syscall stub for setting RT mode and scheduling options */