From f2acf9d2573ebbfb7478e97c4066c128ddaa5a18 Mon Sep 17 00:00:00 2001
From: Jeremy Kerr <jk@ozlabs.org>
Date: Fri, 17 Jan 2014 15:51:54 +0800
Subject: discover: Support DHCP "pathprefix" configuration option

This change implements support for the DHCP "pathprefix" option. We use
the following logic:

 - If pathprefix is present and a full URL, we base the config file
   location on pathprefix + conffile

 - If pathprefix is present but not a full URL, we use it as the path
   component of the URL, and pick up the host from other parameters in
   the DHCP response

 - If no pathprefix is present, we determine the configuration prefix
   from the DHCP bootfile parameter.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---
 discover/network.c    |  1 +
 discover/user-event.c | 93 +++++++++++++++++++++++++++++++--------------------
 2 files changed, 58 insertions(+), 36 deletions(-)

(limited to 'discover')

diff --git a/discover/network.c b/discover/network.c
index 8cc0183..2857076 100644
--- a/discover/network.c
+++ b/discover/network.c
@@ -220,6 +220,7 @@ static void configure_interface_dhcp(struct interface *interface)
 		"-R",
 		"-n",
 		"-O", "pxeconffile",
+		"-O", "pxepathprefix",
 		"-p", pidfile,
 		"-i", interface->name,
 		NULL,
diff --git a/discover/user-event.c b/discover/user-event.c
index 11a54df..7acd237 100644
--- a/discover/user-event.c
+++ b/discover/user-event.c
@@ -232,61 +232,82 @@ static char *parse_ip_addr(struct discover_context *ctx, const char *ip)
 struct pb_url *user_event_parse_conf_url(struct discover_context *ctx,
 		struct event *event, bool *is_complete)
 {
-	const char *conffile, *host, *bootfile;
+	const char *conffile, *pathprefix, *host, *bootfile;
 	char *p, *basedir, *url_str;
 	struct pb_url *url;
 
 	conffile = event_get_param(event, "pxeconffile");
-	if (conffile) {
-		if (is_url(conffile)) {
-			url = pb_url_parse(ctx, conffile);
-		} else {
-			host = parse_host_addr(event);
-			if (!host) {
-				pb_log("%s: host address not found\n",
-						__func__);
-				return NULL;
-			}
-
-			url_str = talloc_asprintf(ctx, "%s%s/%s", "tftp://",
-					host, conffile);
-			url = pb_url_parse(ctx, url_str);
+	pathprefix = event_get_param(event, "pxepathprefix");
+	bootfile = event_get_param(event, "bootfile");
+
+	/* If we're given a conf file, we're able to generate a complete URL to
+	 * the configuration file, and the parser doesn't need to do any
+	 * further autodiscovery */
+	*is_complete = !!conffile;
+
+	/* if conffile is a URL, that's all we need */
+	if (conffile && is_url(conffile)) {
+		url = pb_url_parse(ctx, conffile);
+		return url;
+	}
 
+	/* If we can create a URL from pathprefix (optionally with
+	 * conffile appended to create a complete URL), use that */
+	if (pathprefix && is_url(pathprefix)) {
+		if (conffile) {
+			url_str = talloc_asprintf(ctx, "%s%s",
+					pathprefix, conffile);
+			url = pb_url_parse(ctx, url_str);
 			talloc_free(url_str);
+		} else {
+			url = pb_url_parse(ctx, pathprefix);
 		}
 
-		*is_complete = true;
-	} else {
-		host = parse_host_addr(event);
-		if (!host) {
-			pb_log("%s: host address not found\n", __func__);
-			return NULL;
-		}
+		return url;
+	}
 
-		bootfile = event_get_param(event, "bootfile");
-		if (!bootfile) {
-			pb_log("%s: bootfile param not found\n", __func__);
-			return NULL;
-		}
+	host = parse_host_addr(event);
+	if (!host) {
+		pb_log("%s: host address not found\n", __func__);
+		return NULL;
+	}
+
+	url_str = talloc_asprintf(ctx, "tftp://%s/", host);
+
+	/* if we have a pathprefix, use that directly.. */
+	if (pathprefix) {
+		/* strip leading slashes */
+		while (pathprefix[0] == '/')
+			pathprefix++;
+		url_str = talloc_asprintf_append(url_str, "%s", pathprefix);
+
+	/* ... otherwise, add a path based on the bootfile name, but only
+	 * if conffile isn't an absolute path itself */
+	} else if (bootfile && !(conffile && conffile[0] == '/')) {
 
 		basedir = talloc_strdup(ctx, bootfile);
-		p = strchr(basedir, '/');
+
+		/* strip filename from the bootfile path, leaving only a
+		 * directory */
+		p = strrchr(basedir, '/');
 		if (p)
 			*p = '\0';
 
-		if (!strcmp(basedir,"") || !strcmp(basedir, "."))
-			url_str = talloc_asprintf(ctx, "%s%s/", "tftp://",host);
-		else
-			url_str = talloc_asprintf(ctx, "%s%s/%s/", "tftp://",host,
+		if (strlen(basedir))
+			url_str = talloc_asprintf_append(url_str, "%s/",
 					basedir);
 
-		url = pb_url_parse(ctx, url_str);
-
-		talloc_free(url_str);
 		talloc_free(basedir);
-		*is_complete = false;
 	}
 
+	/* finally, append conffile */
+	if (conffile)
+		url_str = talloc_asprintf_append(url_str, "%s", conffile);
+
+	url = pb_url_parse(ctx, url_str);
+
+	talloc_free(url_str);
+
 	return url;
 }
 
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