Add build-time distribution detection to Makefile

When using the same policy on several hosts with different Linux distributions the DISTRO variable can't be defined in the build.conf of the build directory because this file is tracked with git.

Instead of maintaining a local patch per host to define DISTRO in build.conf or of building using "make DISTRO=...", this commit introduces a DISTRO_DETECT boolean in build.conf which automatically fills DISTRO with the name of the distro of the building host.

DISTRO_DETECT definition is not copied in the installed build.conf file (/usr/share/selinux/refpolicy/include/build.conf) because this file would have the DISTRO variable set.

---
 Makefile                 |  6 ++++++
 build.conf               |  3 +++
 support/detect_distro.sh | 42 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 51 insertions(+)
 create mode 100644 support/detect_distro.sh

Makefile +6 -0

index 45bd45d..3926cd5 100644
@@ -181,6 +181,12 @@ ifeq "$(TYPE)" "mcs"
 endif
 
 # enable distribution-specific policy
+ifeq "$(DISTRO_DETECT)" "y"
+	ifeq "$(DISTRO)" ""
+		DISTRO := $(shell $(SHELL) $(support)/detect_distro.sh)
+	endif
+endif
+
 ifneq ($(DISTRO),)
 	M4PARAM += -D distro_$(DISTRO)
 endif

build.conf +3 -0

index 5a521c4..c00e4b0 100644
@@ -29,6 +29,9 @@ NAME = refpolicy
 # Fedora users should enable redhat.
 #DISTRO = redhat
 
+# Detect distribution at build time if DISTRO is empty
+DISTRO_DETECT = y
+
 # Unknown Permissions Handling
 # The behavior for handling permissions defined in the
 # kernel but missing from the policy.  The permissions

support/detect_distro.sh new file +42 -0

new file mode 100644
index 0000000..d0b4948
@@ -0,0 +1,42 @@
+#!/bin/sh
+# Detect which Linux distribution is running
+
+# Only Linux is supported
+[ "$(uname -s)" = "Linux" ] || exit
+
+# Use LSB release
+LSB_ID=$(lsb_release --id --short 2> /dev/null)
+if [ -n "$LSB_ID" ]
+then
+    echo "$LSB_ID" | tr '[A-Z]' '[a-z]'
+    exit
+fi
+
+# Use OS release
+if [ -r /etc/os-release ]
+then
+    OS_ID=$(sed -n 's/^ID\s*=\s*\(.*\)$/\1/p' /etc/os-release)
+    if [ -n "$OS_ID" ]
+    then
+        echo "$OS_ID"
+        exit
+    fi
+fi
+
+# Use files
+if [ -r /etc/arch-release ]
+then
+    echo "arch"
+elif [ -r /etc/debian_version ]
+then
+    echo "debian"
+elif [ -r /etc/gentoo-release ]
+then
+    echo "gentoo"
+elif [ -r /etc/redhat-release ]
+then
+    echo "redhat"
+elif [ -r /etc/SuSE-release ]
+then
+    echo "suse"
+fi

Quoted 1 line

When using the same policy on several hosts with different Linux

distributions

Quoted 1 line

the DISTRO variable can't be defined in the build.conf of the build

directory

Quoted 3 lines

because this file is tracked with git.

Instead of maintaining a local patch per host to define DISTRO in

build.conf

Quoted 1 line

or of building using "make DISTRO=...", this commit introduces a

DISTRO_DETECT

Quoted 1 line

boolean in build.conf which automatically fills DISTRO with the name of

the

Quoted 4 lines

distro of the building host.

DISTRO_DETECT definition is not copied in the installed build.conf file (/usr/share/selinux/refpolicy/include/build.conf) because this file

would have

Quoted 1 line

the DISTRO variable set.

I'm reluctant to add this, as the refpolicy build system is already more complicated than I'd like. I also feel that the use case is too uncommon.

I suggest that for your scenario that you instead have a local build.conf that is included by the revision-controlled build.conf. Then in the local one you can set DISTRO without putting it on the make command.

Thanks for your suggestion. I've added "-include build-local.conf" to my

While speaking about files which aren't revision-controlled, if I send a patch which creates a .gitignore file which contains most of the lines of http://oss.tresys.com/projects/refpolicy/browser/.gitignore?rev=190b058eaef2551f9045121f9f2e558b901ff733, will it have any chance of being accepted?