Generalize levelFromUid support.

Introduce a levelFrom=none|app|user|all syntax for specifying
per-app, per-user, or per-combination level assignment.
levelFromUid=true|false remains valid syntax but is deprecated.
levelFromUid=true is equivalent to levelFrom=app.

Update check_seapp to accept the new syntax.
Update seapp_contexts to document the new syntax and switch
from levelFromUid=true to levelFrom=app.  No change in behavior.

Change-Id: Ibaddeed9bc3e2586d524efc2f1faa5ce65dea470
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
diff --git a/tools/check_seapp.c b/tools/check_seapp.c
index 8001cea..482d060 100644
--- a/tools/check_seapp.c
+++ b/tools/check_seapp.c
@@ -162,6 +162,7 @@
                 { .name = "domain",         .type = dt_string, .dir = dir_out, .data = NULL },
                 { .name = "type",           .type = dt_string, .dir = dir_out, .data = NULL },
                 { .name = "levelFromUid",   .type = dt_bool,   .dir = dir_out, .data = NULL },
+                { .name = "levelFrom",      .type = dt_string,   .dir = dir_out, .data = NULL },
                 { .name = "level",          .type = dt_string, .dir = dir_out, .data = NULL },
 };
 
@@ -256,6 +257,15 @@
 		goto out;
 	}
 
+	if (!strcasecmp(key, "levelFrom") &&
+	    (strcasecmp(value, "none") && strcasecmp(value, "all") &&
+	     strcasecmp(value, "app") && strcasecmp(value, "user"))) {
+		log_error("Unknown levelFrom=%s on line: %d in file: %s\n",
+			  value, lineno, out_file_name);
+		rc = 0;
+		goto out;
+	}
+
 	/*
 	 * If their is no policy file present,
 	 * then it is not in strict mode so just return.