[RFC PATCH 3/6] btrfs-progs: Makefile: add "install-splitcmd-setcap" target, installs splitcmd binaries with appropriate capabilities

[Axel Burri <axel@tty0.ch>]

Install all $progs_install_splitcmd, and set appropriate linux file
capabilities(7) using setcap(8).

NOTE: while installing, group is hardcoded to "btrfs"! This needs
further discussion.

Signed-off-by: Axel Burri <axel@tty0.ch>
---
 Makefile        | 36 ++++++++++++++++++++++++++++++++++++
 Makefile.inc.in |  1 +
 configure.ac    |  1 +
 3 files changed, 38 insertions(+)

diff --git a/Makefile b/Makefile
index fcfc815a..5a1e2747 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,7 @@
 #   static      build static bnaries, requires static version of the libraries
 #   test        run the full testsuite
 #   install     install to default location (/usr/local)
+#   install-splitcmd-setcap  install splitcmd binaries, and set linux capabilities
 #   clean       clean built binaries (not the documentation)
 #   clean-all   clean as above, clean docs and generated files
 #
@@ -231,6 +232,30 @@ progs_install =
 progs_build =
 endif
 
+# split-command executables, generated by splitcmd-gen.sh
+progs_splitcmd = btrfs-send \
+	btrfs-receive \
+	btrfs-subvolume-list \
+	btrfs-subvolume-show \
+	btrfs-subvolume-snapshot \
+	btrfs-subvolume-delete \
+	btrfs-filesystem-usage \
+	btrfs-qgroup-destroy
+
+progs_install_splitcmd = $(progs_splitcmd)
+
+INSTALL_SETCAP_FLAGS = -m710 -gbtrfs
+
+# linux capabilities(7) needed; used by "install-splitcmd-setcap-%" below
+btrfs_subvolume_show_fcaps = "cap_sys_admin,cap_fowner,cap_dac_read_search"
+btrfs_subvolume_list_fcaps = "cap_sys_admin,cap_fowner,cap_dac_read_search"
+btrfs_subvolume_snapshot_fcaps = "cap_sys_admin,cap_fowner,cap_dac_override,cap_dac_read_search"
+btrfs_subvolume_delete_fcaps = "cap_sys_admin,cap_dac_override"
+btrfs_send_fcaps = "cap_sys_admin,cap_fowner,cap_dac_read_search"
+btrfs_receive_fcaps = "cap_sys_admin,cap_fowner,cap_chown,cap_mknod,cap_setfcap,cap_dac_override,cap_dac_read_search"
+btrfs_filesystem_usage_fcaps = "cap_sys_admin"
+btrfs_qgroup_destroy_fcaps = "cap_sys_admin,cap_dac_override"
+
 # external libs required by various binaries; for btrfs-foo,
 # specify btrfs_foo_libs = <list of libs>; see $($(subst...)) rules below
 btrfs_convert_cflags = -DBTRFSCONVERT_EXT2=$(BTRFSCONVERT_EXT2)
@@ -318,6 +343,7 @@ endif
 		$($(subst -,_,btrfs-$(@:%/$(notdir $@)=%)-cflags))
 
 all: $(progs_build) $(libs_build) $(BUILDDIRS)
+splitcmd: $(progs_splitcmd)
 ifeq ($(PYTHON_BINDINGS),1)
 all: libbtrfsutil_python
 endif
@@ -618,6 +644,7 @@ clean: $(CLEANDIRS)
 	      $(check_defs) \
 	      $(libs) $(lib_links) \
 	      $(progs_static) \
+	      $(progs_splitcmd) \
 	      libbtrfsutil/*.o libbtrfsutil/*.o.d
 ifeq ($(PYTHON_BINDINGS),1)
 	$(Q)cd libbtrfsutil/python; \
@@ -678,6 +705,15 @@ install-static: $(progs_static) $(INSTALLDIRS)
 	# btrfsck is a link to btrfs in the src tree, make it so for installed file as well
 	$(LN_S) -f btrfs.static $(DESTDIR)$(bindir)/btrfsck.static
 
+# install split-command binary, and set linux capabilities(7) defined
+# in btrfs_*_fcaps above, using setcap(8)
+install-splitcmd-setcap-%: %
+	@echo $(INSTALL) -m755 -d $(DESTDIR)$(bindir)
+	@echo $(INSTALL) $(INSTALL_SETCAP_FLAGS) $< $(DESTDIR)$(bindir)
+	@echo $(SETCAP) $($(subst -,_,$<)_fcaps)+ep $(DESTDIR)$(bindir)/$<
+
+install-splitcmd-setcap: $(progs_install_splitcmd) $(patsubst %,install-splitcmd-setcap-%,$(progs_install_splitcmd))
+
 $(INSTALLDIRS):
 	@echo "Making install in $(patsubst install-%,%,$@)"
 	$(Q)$(MAKE) $(MAKEOPTS) -C $(patsubst install-%,%,$@) install
diff --git a/Makefile.inc.in b/Makefile.inc.in
index a86c528e..567e4e6f 100644
--- a/Makefile.inc.in
+++ b/Makefile.inc.in
@@ -10,6 +10,7 @@ AR = @AR@
 RM = @RM@
 RMDIR = @RMDIR@
 INSTALL = @INSTALL@
+SETCAP = @SETCAP@
 DISABLE_DOCUMENTATION = @DISABLE_DOCUMENTATION@
 DISABLE_BTRFSCONVERT = @DISABLE_BTRFSCONVERT@
 BUILD_PROGRAMS = @BUILD_PROGRAMS@
diff --git a/configure.ac b/configure.ac
index df02f206..fefbfd9c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,6 +39,7 @@ AC_PROG_LN_S
 AC_CHECK_TOOL([AR], [ar])
 AC_PATH_PROG([RM], [rm], [rm])
 AC_PATH_PROG([RMDIR], [rmdir], [rmdir])
+AC_PATH_PROG([SETCAP], [setcap], [setcap])
 
 
 AC_CHECK_FUNCS([openat], [],
-- 
2.16.4