From c6a36fdf2fc2e7a1c2bc4c8d16f2a3bb575b5a2f Mon Sep 17 00:00:00 2001
From: Jeremy Kerr <jk@ozlabs.org>
Date: Tue, 16 Apr 2013 15:54:13 +0800
Subject: discover: Add devpath resources

Add a generic resource type, to handle "dev:path"-style file references.

This creates a duplicate of is_prefix_ignorecase, which we'll switch
over to later.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---
 discover/Makefile.am |   1 +
 discover/resource.c  | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++
 discover/resource.h  |  24 +++++++++++
 3 files changed, 138 insertions(+)
 create mode 100644 discover/resource.c

diff --git a/discover/Makefile.am b/discover/Makefile.am
index a858855..a8d07b2 100644
--- a/discover/Makefile.am
+++ b/discover/Makefile.am
@@ -54,6 +54,7 @@ pb_discover_SOURCES = \
 	params.h \
 	pb-discover.c \
 	pb-discover.h \
+	resource.c \
 	resource.h \
 	udev.c \
 	udev.h \
diff --git a/discover/resource.c b/discover/resource.c
new file mode 100644
index 0000000..917a6dc
--- /dev/null
+++ b/discover/resource.c
@@ -0,0 +1,113 @@
+
+#define _GNU_SOURCE
+
+#include <assert.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include <url/url.h>
+#include <talloc/talloc.h>
+
+#include "device-handler.h"
+#include "resource.h"
+#include "paths.h"
+
+static int is_prefix_ignorecase(const char *str, const char *prefix)
+{
+	return !strncasecmp(str, prefix, strlen(prefix));
+}
+
+struct devpath_resource_info {
+	char	*dev, *path;
+};
+
+static struct discover_device *parse_device_string(
+		struct device_handler *handler, const char *devstr)
+{
+	if (is_prefix_ignorecase(devstr, "uuid="))
+		return device_lookup_by_uuid(handler, devstr + strlen("uuid"));
+
+	if (is_prefix_ignorecase(devstr, "label="))
+		return device_lookup_by_label(handler,
+					devstr + strlen("label="));
+
+	return device_lookup_by_name(handler, devstr);
+}
+static void resolve_devpath_against_device(struct resource *res,
+	struct discover_device *dev, const char *path)
+{
+	char *resolved_path = join_paths(res, dev->mount_path, path);
+	res->url = pb_url_parse(res, resolved_path);
+	res->resolved = true;
+}
+
+struct resource *create_devpath_resource(void *ctx,
+	struct discover_device *orig_device,
+	const char *devpath)
+{
+	struct devpath_resource_info *info;
+	char *pos, *devstr, *path;
+	struct resource *res;
+	struct pb_url *url;
+
+	res = talloc(ctx, struct resource);
+
+	pos = strchr(devpath, ':');
+
+	/* do we have a "://" scheme separator? */
+	if (pos && pos[1] && pos[1] == '/' && pos[2] && pos[2] == '/') {
+		url = pb_url_parse(res, devpath);
+
+		if (url->scheme != pb_url_file) {
+			/* not a file? we're ready to go */
+			res->resolved = true;
+			res->url = url;
+		} else {
+			/* we've been passed a file:// URL, which has no device
+			 * specifier. We can resolve against the original
+			 * device */
+			resolve_devpath_against_device(res, orig_device,
+					url->path);
+			talloc_free(url);
+		}
+		return res;
+	}
+
+	/* if there was no device specified, we can resolve now */
+	if (!pos) {
+		resolve_devpath_against_device(res, orig_device, devpath);
+		return res;
+	}
+
+	devstr = talloc_strndup(res, devpath, pos - devpath);
+	path = talloc_strdup(res, pos + 1);
+
+	/* defer resolution until we can find a suitable matching device */
+	info = talloc(res, struct devpath_resource_info);
+	info->dev = devstr;
+	info->path = path;
+
+	res->resolved = false;
+	res->info = info;
+
+	return res;
+}
+
+bool resolve_devpath_resource(struct device_handler *handler,
+		struct resource *res)
+{
+	struct devpath_resource_info *info = res->info;
+	struct discover_device *dev;
+
+	assert(!res->resolved);
+
+	dev = parse_device_string(handler, info->dev);
+
+	if (!dev)
+		return false;
+
+	resolve_devpath_against_device(res, dev, info->path);
+	talloc_free(info);
+
+	return true;
+}
diff --git a/discover/resource.h b/discover/resource.h
index b7e1a46..2debe3c 100644
--- a/discover/resource.h
+++ b/discover/resource.h
@@ -19,5 +19,29 @@ struct resource {
 	};
 };
 
+/**
+ * devpath resources.
+ *
+ * Most resources in config files will be in one of the following formats:
+ *  - URLs
+ *  - device-local filenames (ie, filenames on the currently-discovered dev)
+ *  - other-device filenames (which speficy the device by a string format,
+ *     using a dev:path format).
+ *
+ * The following definitions are a generic resource handler for these types
+ * of resources. By creating resources with create_devpath_resource,
+ * parsers can use resolve_devpath_resource as their resolve_resouce
+ * callback.
+ */
+
+struct resource *create_devpath_resource(void *ctx,
+		struct discover_device *orig_device,
+		const char *devpath);
+
+bool resolve_devpath_resource(struct device_handler *dev,
+		struct resource *res);
+
+
+
 #endif /* RESOURCE_H */
 
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