maint: refactor SMACK interface to a separate module

Consolidate all smack routines and checks in a module.
We replace and wrap the most commonly used smack routines,
which allows removing ifdefs throughout the code.

* gl/lib/smack.h: A new header containing the implementation
of the wrapped and replacement routines.  Note the is_smack_enabled()
routine should be optimized out at compile time when compiled
on a system without libsmack.
* gl/modules/smack: Describe the new module and move the
configure time code here from ...
* m4/jm-macros.m4: ... here.
* bootstrap.conf: Reference the new module.
* src/id.c: Use the routines without ifdefs where possible.
* src/ls.c: Likewise.
* src/mkdir.c: Likewise.
* src/mkfifo.c: Likewise.
* src/mknod.c: Likewise.

1 files changed, 4 insertions, 11 deletions

diff --git a/src/ls.c b/src/ls.c
index af972941a..ae29bcc5d 100644
--- a/src/ls.c
+++ b/src/ls.c
@@ -101,6 +101,7 @@
 #include "obstack.h"
 #include "quote.h"
 #include "quotearg.h"
+#include "smack.h"
 #include "stat-size.h"
 #include "stat-time.h"
 #include "strftime.h"
@@ -115,10 +116,6 @@
 # include <sys/capability.h>
 #endif
 
-#ifdef HAVE_SMACK
-# include <sys/smack.h>
-#endif
-
 #define PROGRAM_NAME (ls_mode == LS_LS ? "ls" \
                       : (ls_mode == LS_MULTI_COL \
                          ? "dir" : "vdir"))
@@ -2754,11 +2751,9 @@ free_ent (struct fileinfo *f)
   free (f->linkname);
   if (f->scontext != UNKNOWN_SECURITY_CONTEXT)
     {
-#ifdef HAVE_SMACK
-      if (smack_smackfs_path ())
+      if (is_smack_enabled ())
         free (f->scontext);
       else
-#endif
         freecon (f->scontext);
     }
 }
@@ -2817,7 +2812,7 @@ getfilecon_cache (char const *file, struct fileinfo *f, bool deref)
     }
   int r = 0;
 #ifdef HAVE_SMACK
-  if (smack_smackfs_path ())
+  if (is_smack_enabled ())
     r = smack_new_label_from_path (file, "security.SMACK64", deref,
                                    &f->scontext);
   else
@@ -3022,11 +3017,9 @@ gobble_file (char const *name, enum filetype type, ino_t inode,
 
           if (err == 0)
             {
-#ifdef HAVE_SMACK
-              if (smack_smackfs_path ())
+              if (is_smack_enabled ())
                 have_scontext = ! STREQ ("_", f->scontext);
               else
-#endif
                 have_scontext = ! STREQ ("unlabeled", f->scontext);
             }
           else