ls: Add support for SELinux and a slightly modified -Z option.

I started with the patches from Red Hat.
The entries below tell how the code evolved.

* src/ls.c (print_long_format, print_file_name_and_frills): When
there is no security context (due to getfilecon/lgetfilecon failing
with e.g. ENOTSUP), print it as "?", not "".
* src/ls.c (print_file_name_and_frills): Make -Z work without -l.
(length_of_file_name_and_frills): Likewise.

* src/ls.c: Remove the --lcontext and --scontext options.
Change the way -Z, --context work so that it no longer implies -l.
Thus, -Z -l will work like -lcontext and -Z without -l will work
like --scontext.

Adjust tests to reflect new 'ls -l' syntax -- affects only
systems with SELinux when operating on a file with no ACL.
These tests assumed that everything before the first space on
each line is the 10-byte mode string.  But there may also be a "+"
in the 11th column, just before the space.  However, note that this
is not new.  The same thing would have happened even without the
change below, when listing a file with an ACL.
* tests/chmod/equals, tests/cp/cp-parents, tests/cp/fail-perm:
* tests/cp/link-preserve, tests/install/basic-1, tests/misc/mknod:
* tests/mkdir/parents, tests/mkdir/special-1, tests/mv/partition-perm:

Don't make compilation depend on USE_ACL.  An SELinux security
context counts as an "alternate access control method", so ls
must output a "+" for each file with a security context.
* src/ls.c [struct fileinfo] (have_acl): Declare unconditionally.
(FILE_HAS_ACL): Remove macro definition.  Use f->have_acl directly.
(gobble_file): Record whether a file has a security context, and
update the condition used to determine whether to print the "+".
(gobble_file): Call getfilecon/lgetfilecon also when
format == long_format, so that we get the "+".

* src/ls.c (gobble_file): Add a comment explaining why (with a
security context option) ls doesn't exit nonzero due to e.g.,
getfilecon failing with errno == ENOTSUP.

* src/ls.c (gobble_file): Ignore failure of getfilecon if it's due
to ENOTSUP.

* src/ls.c (gobble_file): Factor out three small blocks using
getfilecon and lgetfilecon.
Don't ignore return value from getfilecon and lgetfilecon.

* src/ls.c (print_long_format): Don't use ?: (empty 2nd arg with C
ternary operator).
(print_scontext_format): Likewise.
(print_scontext): Declare to be "bool", not int.  Adjust uses.

* src/Makefile.am (dir_LDADD, ls_LDADD, vdir_LDADD): Add $(LIB_SELINUX).

* tests/misc/chcon: New file.
* tests/misc/chcon-fail: New file.
* tests/Makefile.am (check-root): Run new, root-only misc/chcon test.
* tests/misc/Makefile.am (TESTS): Add chcon and chcon-fail.

* tests/misc/Makefile.am (TESTS): Add selinux.
* tests/misc/selinux: New file.
* tests/help-version: Skip chcon.

1 files changed, 73 insertions, 0 deletions

diff --git a/tests/misc/chcon b/tests/misc/chcon
new file mode 100755
index 000000000..88c009baf
--- /dev/null
+++ b/tests/misc/chcon
@@ -0,0 +1,73 @@
+#!/bin/sh
+# exercise chcon
+
+if test "$VERBOSE" = yes; then
+  set -x
+  chcon --version
+fi
+
+. $srcdir/../lang-default
+PRIV_CHECK_ARG=require-root . $srcdir/../priv-check
+
+pwd=`pwd`
+t0=`echo "$0"|sed 's,.*/,,'`.tmp; tmp=$t0/$$
+trap 'status=$?; cd $pwd; chmod -R u+rwx $t0; rm -rf $t0 && exit $status' 0
+trap '(exit $?); exit $?' 1 2 13 15
+
+framework_failure=0
+mkdir -p $tmp || framework_failure=1
+cd $tmp || framework_failure=1
+mkdir -p d/sub/s2 || framework_failure=1
+touch f g d/sub/1 d/sub/2 || framework_failure=1
+
+if test $framework_failure = 1; then
+  echo "$0: failure in testing framework" 1>&2
+  (exit 1); exit 1
+fi
+
+fail=0
+
+# Set to a specified context.
+u1=root
+r1=object_r
+t1=tmp_t
+ctx=$u1:$r1:$t1
+chcon $ctx f || fail=1
+stat --printf='f|%C\n' f > out || fail=1
+
+# Use --reference.
+chcon --ref=f g || fail=1
+stat --printf='g|%C\n' g >> out || fail=1
+
+# Change the individual parts of the context, one by one.
+u2=user_u
+r2=object_r
+t2=file_t
+l2=SystemLow-SystemHigh
+for i in --user=$u2 --role=$r2 --type=$t2 --range=$l2; do
+  chcon $i f || fail=1
+  stat --printf="f|$i|"'%C\n' f >> out || fail=1
+done
+
+# Same, but change back using the short-named options.
+for i in -u$u1 -r$r1 -t$t1; do
+  chcon $i f || fail=1
+  stat --printf="f|$i|"'%C\n' f >> out || fail=1
+done
+
+cat <<EOF > exp || fail=1
+f|$ctx
+g|$ctx
+f|--user=$u2|$u2:$r1:$t1
+f|--role=$r2|$u2:$r2:$t1
+f|--type=$t2|$u2:$r2:$t2
+f|--range=$l2|$u2:$r2:$t2:$l2
+f|-uroot|root:object_r:file_t:SystemLow-SystemHigh
+f|-robject_r|root:object_r:file_t:SystemLow-SystemHigh
+f|-ttmp_t|root:object_r:tmp_t:SystemLow-SystemHigh
+EOF
+
+cmp out exp || fail=1
+test $fail = 1 && diff out exp 2> /dev/null
+
+(exit $fail); exit $fail