[PATCH 1/3] libselinux: string and compute_create functions (resend)

[Eamon Walsh <ewalsh@tycho.nsa.gov>]

Resending patch 1, was whitespace damaged.

--
 include/selinux/selinux.h |   12 ++++-
 src/avc.c                 |   99 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+), 2 deletions(-)

--
Index: libselinux/src/avc.c
===================================================================
--- libselinux/src/avc.c	(revision 2307)
+++ libselinux/src/avc.c	(working copy)
@@ -1338,6 +1338,105 @@
 	return 0;
 }
 
+const char *security_class_to_string(security_class_t tclass)
+{
+	tclass = (tclass > 0 && tclass < NCLASSES) ? tclass : 0;
+	return class_to_string_data.str + class_to_string[tclass];
+}
+
+const char *security_av_perm_to_string(security_class_t tclass,
+				       access_vector_t av)
+{
+	const uint16_t *common_pts_idx = 0;
+	access_vector_t common_base = 0;
+	unsigned int i;
+
+	if (!av)
+		return NULL;
+
+	for (i = 0; i < ARRAY_SIZE(av_inherit); i++) {
+		if (av_inherit[i].tclass == tclass) {
+			common_pts_idx =
+			    &common_perm_to_string.data[av_inherit[i].
+							common_pts_idx];
+			common_base = av_inherit[i].common_base;
+			break;
+		}
+	}
+
+	if (av < common_base) {
+		i = 0;
+		while (!(av & 1)) {
+			av >>= 1;
+			i++;
+		}
+		return common_perm_to_string_data.str + common_pts_idx[i];
+	}
+
+	for (i = 0; i < NVECTORS; i++) {
+		if (av_perm_to_string[i].tclass == tclass &&
+		    av_perm_to_string[i].value == av)
+			return av_perm_to_string_data.str
+				+ av_perm_to_string[i].nameidx;
+	}
+
+	return NULL;
+}
+
+int security_av_string(security_class_t tclass, access_vector_t av, char **res)
+{
+	unsigned int i = 0;
+	size_t len = 5;
+	access_vector_t tmp = av;
+	int rc = 0;
+	const char *str;
+	char *ptr;
+
+	/* first pass computes the required length */
+	while (tmp) {
+		if (tmp & 1) {
+			str = security_av_perm_to_string(tclass, av & (1<<i));
+			if (str)
+				len += strlen(str) + 1;
+			else {
+				rc = -1;
+				errno = EINVAL;
+				goto out;
+			}
+		}
+		tmp >>= 1;
+		i++;
+	}
+
+	*res = malloc(len);
+	if (!*res) {
+		rc = -1;
+		goto out;
+	}
+
+	/* second pass constructs the string */
+	i = 0;
+	tmp = av;
+	ptr = *res;
+
+	if (!av) {
+		sprintf(ptr, "null");
+		goto out;
+	}
+
+	ptr += sprintf(ptr, "{ ");
+	while (tmp) {
+		if (tmp & 1)
+			ptr += sprintf(ptr, "%s ", security_av_perm_to_string(
+					       tclass, av & (1<<i)));
+		tmp >>= 1;
+		i++;
+	}
+	sprintf(ptr, "}");
+out:
+	return rc;
+}
+
 void print_access_vector(security_class_t tclass, access_vector_t av)
 {
 	const uint16_t *common_pts_idx = 0;
Index: libselinux/include/selinux/selinux.h
===================================================================
--- libselinux/include/selinux/selinux.h	(revision 2307)
+++ libselinux/include/selinux/selinux.h	(working copy)
@@ -277,13 +277,21 @@
 
 /* Common helpers */
 
-/* Return the security class value for a given class name. */
+/* Convert between security class values and string names */
 	extern security_class_t string_to_security_class(const char *name);
+	extern const char *security_class_to_string(security_class_t cls);
 
-/* Return an access vector for a given class and permission name. */
+/* Convert between individual access vector permissions and string names */
+	extern const char *security_av_perm_to_string(security_class_t tclass,
+						      access_vector_t perm);
 	extern access_vector_t string_to_av_perm(security_class_t tclass,
 						 const char *name);
 
+/* Returns an access vector in a string representation.  User must free the
+ * returned string via free(). */
+	extern int security_av_string(security_class_t tclass,
+				      access_vector_t av, char **result);
+
 /* Display an access vector in a string representation. */
 	extern void print_access_vector(security_class_t tclass,
 					access_vector_t av);



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