SELinux: turn mount options strings into defines

Convert the strings used for mount options into #defines rather than
retyping the string throughout the SELinux code.

Signed-off-by: Eric Paris <[e-mail]>
Acked-by: Stephen Smalley <[e-mail]>
Signed-off-by: James Morris <[e-mail]>

security/selinux/hooks.c

···
 };
 
 static match_table_t tokens = {
-	{Opt_context, "context=%s"},
-	{Opt_fscontext, "fscontext=%s"},
-	{Opt_defcontext, "defcontext=%s"},
-	{Opt_rootcontext, "rootcontext=%s"},
+	{Opt_context, CONTEXT_STR "%s"},
+	{Opt_fscontext, FSCONTEXT_STR "%s"},
+	{Opt_defcontext, DEFCONTEXT_STR "%s"},
+	{Opt_rootcontext, ROOTCONTEXT_STR "%s"},
 	{Opt_error, NULL},
 };
 
···
 
 static inline int selinux_option(char *option, int len)
 {
-	return (match_prefix("context=", sizeof("context=")-1, option, len) ||
-	        match_prefix("fscontext=", sizeof("fscontext=")-1, option, len) ||
-	        match_prefix("defcontext=", sizeof("defcontext=")-1, option, len) ||
-		match_prefix("rootcontext=", sizeof("rootcontext=")-1, option, len));
+	return (match_prefix(CONTEXT_STR, sizeof(CONTEXT_STR)-1, option, len) ||
+		match_prefix(FSCONTEXT_STR, sizeof(FSCONTEXT_STR)-1, option, len) ||
+		match_prefix(DEFCONTEXT_STR, sizeof(DEFCONTEXT_STR)-1, option, len) ||
+		match_prefix(ROOTCONTEXT_STR, sizeof(ROOTCONTEXT_STR)-1, option, len));
 }
 
 static inline void take_option(char **to, char *from, int *first, int len)

security/selinux/include/security.h

···
 #define ROOTCONTEXT_MNT	0x04
 #define DEFCONTEXT_MNT	0x08
 
+#define CONTEXT_STR	"context="
+#define FSCONTEXT_STR	"fscontext="
+#define ROOTCONTEXT_STR	"rootcontext="
+#define DEFCONTEXT_STR	"defcontext="
+
 struct netlbl_lsm_secattr;
 
 extern int selinux_enabled;