Move dir_entry_xattr_t from libio to libsquashfs

The structure and functions are renamed to sqfs_xattr_* instead,
an additional helper is added to accept an encoded xattr.
Documentation and unit test are added as well.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

3 files changed, 211 insertions, 1 deletions

diff --git a/lib/sqfs/Makemodule.am b/lib/sqfs/Makemodule.am
index 3500aad..d54134c 100644
--- a/lib/sqfs/Makemodule.am
+++ b/lib/sqfs/Makemodule.am
@@ -107,6 +107,9 @@ pkgconfig_DATA += lib/sqfs/libsquashfs1.pc
 test_abi_SOURCES = lib/sqfs/test/abi.c
 test_abi_LDADD = libsquashfs.la libcompat.a
 
+test_xattr_SOURCES = lib/sqfs/test/xattr.c
+test_xattr_LDADD = libsquashfs.la libcompat.a
+
 test_table_SOURCES = lib/sqfs/test/table.c
 test_table_LDADD = libsquashfs.la libcompat.a
 
@@ -120,7 +123,7 @@ test_get_node_path_SOURCES = lib/sqfs/test/get_node_path.c
 test_get_node_path_LDADD = libcommon.a libsquashfs.la libcompat.a
 
 LIBSQFS_TESTS = \
-	test_abi test_table test_xattr_writer test_get_node_path
+	test_abi test_xattr test_table test_xattr_writer test_get_node_path
 
 noinst_PROGRAMS += xattr_benchmark
 
diff --git a/lib/sqfs/src/xattr/xattr.c b/lib/sqfs/src/xattr/xattr.c
index 29ecebf..9dc284d 100644
--- a/lib/sqfs/src/xattr/xattr.c
+++ b/lib/sqfs/src/xattr/xattr.c
@@ -8,8 +8,10 @@
 #include "config.h"
 #include "sqfs/xattr.h"
 #include "sqfs/error.h"
+#include "compat.h"
 
 #include <string.h>
+#include <stdlib.h>
 
 static const struct {
 	const char *prefix;
@@ -47,3 +49,97 @@ const char *sqfs_get_xattr_prefix(SQFS_XATTR_TYPE id)
 
 	return NULL;
 }
+
+static sqfs_xattr_t *mkxattr(const char *prefix, const char *key,
+			     const sqfs_u8 *value, size_t value_len)
+{
+	size_t pfx_len = (prefix == NULL) ? 0 : strlen(prefix);
+	size_t key_len = strlen(key);
+	sqfs_xattr_t *out;
+	size_t len;
+
+	/* len = pfx_len + (key_len + 1) + (value_len + 1) + sizeof(*out) */
+	if (SZ_ADD_OV(pfx_len, key_len, &len))
+		return NULL;
+	if (SZ_ADD_OV(len, value_len, &len))
+		return NULL;
+	if (SZ_ADD_OV(len, 2, &len))
+		return NULL;
+	if (SZ_ADD_OV(len, sizeof(*out), &len))
+		return NULL;
+
+	out = calloc(1, len);
+
+	if (out != NULL) {
+		size_t value_offset = pfx_len + key_len + 1;
+
+		out->key = (const char *)out->data;
+		out->value = out->data + value_offset;
+		out->value_len = value_len;
+
+		if (prefix != NULL)
+			memcpy(out->data, prefix, pfx_len);
+
+		memcpy(out->data + pfx_len, key, key_len);
+		memcpy(out->data + value_offset, value, value_len);
+	}
+
+	return out;
+}
+
+sqfs_xattr_t *sqfs_xattr_create(const char *key, const sqfs_u8 *value,
+				size_t value_len)
+{
+	return mkxattr(NULL, key, value, value_len);
+}
+
+int sqfs_xattr_create_prefixed(sqfs_xattr_t **out, sqfs_u16 id,
+			       const char *key, const sqfs_u8 *value,
+			       size_t value_len)
+{
+	const char *prefix = sqfs_get_xattr_prefix(id & (~SQFS_XATTR_FLAG_OOL));
+
+	if (prefix == NULL) {
+		*out = NULL;
+		return SQFS_ERROR_UNSUPPORTED;
+	}
+
+	*out = mkxattr(prefix, key, value, value_len);
+	if (*out == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	return 0;
+}
+
+sqfs_xattr_t *sqfs_xattr_list_copy(const sqfs_xattr_t *list)
+{
+	sqfs_xattr_t *copy = NULL, *copy_last = NULL;
+
+	for (const sqfs_xattr_t *it = list; it != NULL; it = it->next) {
+		sqfs_xattr_t *new = mkxattr(NULL, it->key,
+					    it->value, it->value_len);
+		if (new == NULL) {
+			sqfs_xattr_list_free(copy);
+			return NULL;
+		}
+
+		if (copy_last == NULL) {
+			copy = new;
+		} else {
+			copy_last->next = new;
+		}
+
+		copy_last = new;
+	}
+
+	return copy;
+}
+
+void sqfs_xattr_list_free(sqfs_xattr_t *list)
+{
+	while (list != NULL) {
+		sqfs_xattr_t *old = list;
+		list = list->next;
+		free(old);
+	}
+}
diff --git a/lib/sqfs/test/xattr.c b/lib/sqfs/test/xattr.c
new file mode 100644
index 0000000..a5222f4
--- /dev/null
+++ b/lib/sqfs/test/xattr.c
@@ -0,0 +1,111 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * xattr.c
+ *
+ * Copyright (C) 2023 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "compat.h"
+#include "util/test.h"
+
+#include "sqfs/xattr.h"
+#include "sqfs/error.h"
+
+int main(int argc, char **argv)
+{
+	sqfs_xattr_t *ent, *ent2, *list;
+	const char *str;
+	int id, ret;
+	(void)argc; (void)argv;
+
+	/* prefix API */
+	id = sqfs_get_xattr_prefix_id("user.mime_type");
+	TEST_EQUAL_I(id, SQFS_XATTR_USER);
+
+	str = sqfs_get_xattr_prefix(id);
+	TEST_STR_EQUAL(str, "user.");
+
+	id = sqfs_get_xattr_prefix_id("security.selinux");
+	TEST_EQUAL_I(id, SQFS_XATTR_SECURITY);
+
+	str = sqfs_get_xattr_prefix(id);
+	TEST_STR_EQUAL(str, "security.");
+
+	id = sqfs_get_xattr_prefix_id("trusted.bla");
+	TEST_EQUAL_I(id, SQFS_XATTR_TRUSTED);
+
+	str = sqfs_get_xattr_prefix(id);
+	TEST_STR_EQUAL(str, "trusted.");
+
+	id = sqfs_get_xattr_prefix_id("system.acl");
+	TEST_EQUAL_I(id, SQFS_ERROR_UNSUPPORTED);
+
+	str = sqfs_get_xattr_prefix(id);
+	TEST_NULL(str);
+
+	/* combined entry API */
+	ent = sqfs_xattr_create("foo.bar", (const sqfs_u8 *)"Hello, World!", 5);
+	TEST_NOT_NULL(ent);
+	TEST_EQUAL_UI(ent->value_len, 5);
+	TEST_STR_EQUAL(ent->key, "foo.bar");
+	TEST_STR_EQUAL((const char *)ent->value, "Hello");
+	sqfs_xattr_list_free(ent);
+
+	/* with prefix */
+	ret = sqfs_xattr_create_prefixed(&ent, SQFS_XATTR_SECURITY, "selinux",
+					 (const sqfs_u8 *)"Hello, World!", 5);
+	TEST_EQUAL_I(ret, 0);
+	TEST_NOT_NULL(ent);
+	TEST_EQUAL_UI(ent->value_len, 5);
+	TEST_STR_EQUAL(ent->key, "security.selinux");
+	TEST_STR_EQUAL((const char *)ent->value, "Hello");
+	sqfs_xattr_list_free(ent);
+
+	ret = sqfs_xattr_create_prefixed(&ent, 42, "selinux",
+					 (const sqfs_u8 *)"Hello, World!", 5);
+	TEST_EQUAL_I(ret, SQFS_ERROR_UNSUPPORTED);
+	TEST_NULL(ent);
+
+	/* list copy */
+	ent = sqfs_xattr_create("foo.bar", (const sqfs_u8 *)"Hello, World!", 5);
+	TEST_NOT_NULL(ent);
+
+	ent2 = sqfs_xattr_create("bla.blu", (const sqfs_u8 *)"test", 4);
+	TEST_NOT_NULL(ent2);
+
+	list = sqfs_xattr_list_copy(NULL);
+	TEST_NULL(list);
+
+	list = sqfs_xattr_list_copy(ent);
+	TEST_NOT_NULL(list);
+	TEST_ASSERT(list != ent);
+	TEST_STR_EQUAL(list->key, ent->key);
+	TEST_STR_EQUAL((const char *)list->value, (const char *)ent->value);
+	TEST_EQUAL_UI(list->value_len, ent->value_len);
+	sqfs_xattr_list_free(list);
+
+	ent->next = ent2;
+	ent2->next = NULL;
+
+	list = sqfs_xattr_list_copy(ent);
+	TEST_NOT_NULL(list);
+	TEST_ASSERT(list != ent && list != ent2);
+	TEST_STR_EQUAL(list->key, ent->key);
+	TEST_STR_EQUAL((const char *)list->value, (const char *)ent->value);
+	TEST_EQUAL_UI(list->value_len, ent->value_len);
+
+	TEST_NOT_NULL(list->next);
+	TEST_ASSERT(list->next != ent && list->next != ent2);
+	TEST_STR_EQUAL(list->next->key, ent2->key);
+	TEST_STR_EQUAL((const char *)list->next->value,
+		       (const char *)ent2->value);
+	TEST_EQUAL_UI(list->next->value_len, ent2->value_len);
+	sqfs_xattr_list_free(list);
+
+	ent->next = NULL;
+	ent2->next = NULL;
+	sqfs_xattr_list_free(ent);
+	sqfs_xattr_list_free(ent2);
+
+	return EXIT_SUCCESS;
+}