[PATCH v2 1/2] libselinux: support multiple spec_files

["Thiébaud Weksteen" <tweek@google.com>]

Update the existing backends to potentially allocate multiple
spec_files. This commit simply adds a level of indirection but does not
change any current behaviour. It will facilitate the gradual migration
of backends to multiple context files.

In selabel_fini(), compat_validate() is updated to use the first
spec_file only, for legacy validation error reporting. selabel_open() is
already performing context validation if requested against individual
file paths (see insert_spec).

Signed-off-by: Thiébaud Weksteen <tweek@google.com>
---
Changes since v1:
- Use sizeof(*rec->spec_files) instead of sizeof(path) as suggested by
  Stephen.

 libselinux/src/label.c          | 10 ++++++++--
 libselinux/src/label_db.c       | 11 +++++++++--
 libselinux/src/label_file.c     |  8 ++++++--
 libselinux/src/label_internal.h |  5 +++--
 libselinux/src/label_media.c    |  8 +++++++-
 libselinux/src/label_x.c        |  8 +++++++-
 6 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/libselinux/src/label.c b/libselinux/src/label.c
index 991b9769..4a97d3bc 100644
--- a/libselinux/src/label.c
+++ b/libselinux/src/label.c
@@ -162,7 +162,7 @@ static int selabel_fini(const struct selabel_handle *rec,
 	char *ctx_trans;
 	int rc;
 
-	if (compat_validate(rec, lr, rec->spec_file, lr->lineno))
+	if (compat_validate(rec, lr, rec->spec_files[0], lr->lineno))
 		return -1;
 
 	if (!translating)
@@ -398,11 +398,17 @@ int selabel_digest(struct selabel_handle *rec, unsigned char **digest,
 
 void selabel_close(struct selabel_handle *rec)
 {
+	size_t i;
+
 	if (rec->digest)
 		selabel_digest_fini(rec->digest);
 	if (rec->func_close)
 		rec->func_close(rec);
-	free(rec->spec_file);
+	if (rec->spec_files) {
+		for (i = 0; i < rec->spec_files_len; i++)
+			free(rec->spec_files[i]);
+		free(rec->spec_files);
+	}
 	free(rec);
 }
 
diff --git a/libselinux/src/label_db.c b/libselinux/src/label_db.c
index bafa9328..53731470 100644
--- a/libselinux/src/label_db.c
+++ b/libselinux/src/label_db.c
@@ -302,12 +302,19 @@ static catalog_t *db_init(const struct selinux_opt *opts, unsigned nopts,
 		errno = EINVAL;
 		return NULL;
 	}
-	rec->spec_file = strdup(path);
-	if (!rec->spec_file) {
+	rec->spec_files = calloc(1, sizeof(*rec->spec_files));
+	if (!rec->spec_files) {
 		free(catalog);
 		fclose(filp);
 		return NULL;
 	}
+	rec->spec_files[0] = strdup(path);
+	if (!rec->spec_files[0]) {
+		free(catalog);
+		fclose(filp);
+		return NULL;
+	}
+	rec->spec_files_len = 1;
 
 	/*
 	 * Parse for each lines
diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c
index 0c0499eb..d91e1462 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -1549,9 +1549,13 @@ static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
 		goto finish;
 	}
 
-	rec->spec_file = strdup(path);
-	if (!rec->spec_file)
+	rec->spec_files = calloc(1, sizeof(*rec->spec_files));
+	if (!rec->spec_files)
 		goto finish;
+	rec->spec_files[0] = strdup(path);
+	if (!rec->spec_files[0])
+		goto finish;
+	rec->spec_files_len = 1;
 
 	/*
 	 * The do detailed validation of the input and fill the spec array
diff --git a/libselinux/src/label_internal.h b/libselinux/src/label_internal.h
index 4ff39d96..d54053df 100644
--- a/libselinux/src/label_internal.h
+++ b/libselinux/src/label_internal.h
@@ -96,10 +96,11 @@ struct selabel_handle {
 	void *data;
 
 	/*
-	 * The main spec file used. Note for file contexts the local and/or
+	 * The spec files used. Note for file contexts the local and/or
 	 * homedirs could also have been used to resolve a context.
 	 */
-	char *spec_file;
+	size_t spec_files_len;
+	char **spec_files;
 
 	/* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set */
 	struct selabel_digest *digest;
diff --git a/libselinux/src/label_media.c b/libselinux/src/label_media.c
index 957fcfd3..f315abc3 100644
--- a/libselinux/src/label_media.c
+++ b/libselinux/src/label_media.c
@@ -109,7 +109,13 @@ static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
 		errno = EINVAL;
 		goto finish;
 	}
-	rec->spec_file = strdup(path);
+	rec->spec_files = calloc(1, sizeof(*rec->spec_files));
+	if (!rec->spec_files)
+		goto finish;
+	rec->spec_files[0] = strdup(path);
+	if (!rec->spec_files[0])
+		goto finish;
+	rec->spec_files_len = 1;
 
 	/* 
 	 * Perform two passes over the specification file.
diff --git a/libselinux/src/label_x.c b/libselinux/src/label_x.c
index 0c525bfc..b528a019 100644
--- a/libselinux/src/label_x.c
+++ b/libselinux/src/label_x.c
@@ -139,7 +139,13 @@ static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
 		errno = EINVAL;
 		goto finish;
 	}
-	rec->spec_file = strdup(path);
+	rec->spec_files = calloc(1, sizeof(*rec->spec_files));
+	if (!rec->spec_files)
+		goto finish;
+	rec->spec_files[0] = strdup(path);
+	if (!rec->spec_files[0])
+		goto finish;
+	rec->spec_files_len = 1;
 
 	/* 
 	 * Perform two passes over the specification file.
-- 
2.55.0.229.g6434b31f56-goog