maint: fix const correctness warnings with security_context_t

The security_context_t type was always an artificial separation
from a standard char* string, and various libselinux using code
assumed both were synonymous.  In addition, prior to libselinux 2.3
function declarations were incorrect wrt constness of this type.
Here we replace security_context_t with char*, and also
provide a wrapper function to cater for the const issue on
older libselinux.

* src/system.h (se_const): A new function to avoid and identify
the const issue on older libselinux.
* src/copy.c: s/security_context_t/char */.
* src/cp.c: Likewise.
* src/id.c: Likewise.
* src/install.c: Likewise.
* src/ls.c: Likewise.
* src/mkdir.c: Likewise.
* src/mkfifo.c: Likewise.
* src/mknod.c: Likewise.
* src/runcon.c: Likewise.
* src/selinux.c: Likewise.
* tests/cp/no-ctx.sh: Likewise.
* src/chcon.c: Likesize.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/cp.c b/src/cp.c
index a2541161e..99cafa7f5 100644
--- a/src/cp.c
+++ b/src/cp.c
@@ -926,7 +926,7 @@ main (int argc, char **argv)
   bool copy_contents = false;
   char *target_directory = NULL;
   bool no_target_directory = false;
-  security_context_t scontext = NULL;
+  char const *scontext = NULL;
 
   initialize_main (&argc, &argv);
   set_program_name (argv[0]);
@@ -1196,7 +1196,7 @@ main (int argc, char **argv)
        if (scontext)
          restorecon (dst_path, 0, true);
    */
-  if (scontext && setfscreatecon (scontext) < 0)
+  if (scontext && setfscreatecon (se_const (scontext)) < 0)
     error (EXIT_FAILURE, errno,
            _("failed to set default file creation context to %s"),
            quote (scontext));