discover/pxe: pxe parser should only treat "::" paths as absolute

PXELinux treats all paths as relative, requiring a "::/path" syntax for
truly absolute URLs.

This change implements the same behaviour in petitboot, and updates the
testcases to suit.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

8 files changed, 121 insertions, 7 deletions

diff --git a/discover/pxe-parser.c b/discover/pxe-parser.c
index 17ae55e..98e1603 100644
--- a/discover/pxe-parser.c
+++ b/discover/pxe-parser.c
@@ -28,6 +28,44 @@ static void pxe_finish(struct conf_context *conf)
 		discover_context_add_boot_option(conf->dc, info->opt);
 }
 
+/* We need a slightly modified version of pb_url_join, to allow for the
+ * pxelinux "::filename" syntax for absolute URLs
+ */
+static struct pb_url *pxe_url_join(void *ctx, const struct pb_url *url,
+		const char *s)
+{
+	struct pb_url *new_url;
+	int len;
+
+	len = strlen(s);
+
+	if (len > 2 && s[0] == ':' && s[1] == ':') {
+		char *tmp;
+
+		if (s[2] == '/') {
+			/* ::/path -> /path */
+			tmp = talloc_strdup(ctx, s+2);
+		} else {
+			/* ::path -> /path */
+			tmp = talloc_strdup(ctx, s+1);
+			tmp[0] = '/';
+		}
+
+		new_url = pb_url_join(ctx, url, tmp);
+
+		talloc_free(tmp);
+
+	} else {
+		const char *tmp;
+		/* strip leading slashes */
+		for (tmp = s; *tmp == '/'; tmp++);
+			;
+		new_url = pb_url_join(ctx, url, tmp);
+	}
+
+	return new_url;
+}
+
 static void pxe_process_pair(struct conf_context *ctx,
 		const char *name, char *value)
 {
@@ -72,11 +110,11 @@ static void pxe_process_pair(struct conf_context *ctx,
 		return;
 
 	if (streq(name, "KERNEL")) {
-		url = pb_url_join(ctx->dc, ctx->dc->conf_url, value);
+		url = pxe_url_join(ctx->dc, ctx->dc->conf_url, value);
 		opt->boot_image = create_url_resource(opt, url);
 
 	} else if (streq(name, "INITRD")) {
-		url = pb_url_join(ctx->dc, ctx->dc->conf_url, value);
+		url = pxe_url_join(ctx->dc, ctx->dc->conf_url, value);
 		opt->initrd = create_url_resource(opt, url);
 
 	} else if (streq(name, "APPEND")) {
@@ -90,7 +128,7 @@ static void pxe_process_pair(struct conf_context *ctx,
 			end = strchrnul(str, ' ');
 			*end = '\0';
 
-			url = pb_url_join(ctx->dc, ctx->dc->conf_url, str);
+			url = pxe_url_join(ctx->dc, ctx->dc->conf_url, str);
 			opt->initrd = create_url_resource(opt, url);
 		}
 	}
diff --git a/test/parser/Makefile.am b/test/parser/Makefile.am
index aeb16d8..62770d2 100644
--- a/test/parser/Makefile.am
+++ b/test/parser/Makefile.am
@@ -67,6 +67,8 @@ TESTS = \
 	test-pxe-non-url-pathprefix-with-conf \
 	test-pxe-pathprefix-discover \
 	test-pxe-pathprefix-discover-mac \
+	test-pxe-path-resolve-relative \
+	test-pxe-path-resolve-absolute \
 	test-unresolved-remove
 
 $(TESTS): %: %.embedded-config.o
diff --git a/test/parser/test-pxe-non-url-pathprefix-with-conf.c b/test/parser/test-pxe-non-url-pathprefix-with-conf.c
index 36d4726..b8cc2c2 100644
--- a/test/parser/test-pxe-non-url-pathprefix-with-conf.c
+++ b/test/parser/test-pxe-non-url-pathprefix-with-conf.c
@@ -34,5 +34,6 @@ void run_test(struct parser_test *test)
 
 	check_resolved_url_resource(opt->boot_image,
 			"tftp://host/path/to/./kernel");
-	check_resolved_url_resource(opt->initrd, "tftp://host/initrd");
+	check_resolved_url_resource(opt->initrd,
+			"tftp://host/path/to/initrd");
 }
diff --git a/test/parser/test-pxe-path-resolve-absolute.c b/test/parser/test-pxe-path-resolve-absolute.c
new file mode 100644
index 0000000..04502fc
--- /dev/null
+++ b/test/parser/test-pxe-path-resolve-absolute.c
@@ -0,0 +1,36 @@
+
+#include "parser-test.h"
+
+#if 0 /* PARSER_EMBEDDED_CONFIG */
+label linux
+kernel ::vmlinux
+initrd ::/initrd
+#endif
+
+void run_test(struct parser_test *test)
+{
+	struct discover_boot_option *opt;
+	struct discover_context *ctx;
+
+	test_read_conf_embedded_url(test, "tftp://host/path/conf.txt");
+
+	test_set_event_source(test);
+	test_set_event_param(test->ctx->event, "siaddr", "host");
+	test_set_event_param(test->ctx->event, "pxeconffile", "path/conf.txt");
+
+	test_run_parser(test, "pxe");
+
+	ctx = test->ctx;
+
+	check_boot_option_count(ctx, 1);
+	opt = get_boot_option(ctx, 0);
+
+	check_name(opt, "linux");
+
+	/* even though the initrd is specifed as /initrd, pxelinux treats
+	 * this as relative. */
+	check_resolved_url_resource(opt->boot_image,
+			"tftp://host/vmlinux");
+	check_resolved_url_resource(opt->initrd,
+			"tftp://host/initrd");
+}
diff --git a/test/parser/test-pxe-path-resolve-relative.c b/test/parser/test-pxe-path-resolve-relative.c
new file mode 100644
index 0000000..920c139
--- /dev/null
+++ b/test/parser/test-pxe-path-resolve-relative.c
@@ -0,0 +1,36 @@
+
+#include "parser-test.h"
+
+#if 0 /* PARSER_EMBEDDED_CONFIG */
+label linux
+kernel vmlinux
+initrd /initrd
+#endif
+
+void run_test(struct parser_test *test)
+{
+	struct discover_boot_option *opt;
+	struct discover_context *ctx;
+
+	test_read_conf_embedded_url(test, "tftp://host/path/conf.txt");
+
+	test_set_event_source(test);
+	test_set_event_param(test->ctx->event, "siaddr", "host");
+	test_set_event_param(test->ctx->event, "pxeconffile", "path/conf.txt");
+
+	test_run_parser(test, "pxe");
+
+	ctx = test->ctx;
+
+	check_boot_option_count(ctx, 1);
+	opt = get_boot_option(ctx, 0);
+
+	check_name(opt, "linux");
+
+	/* even though the initrd is specifed as /initrd, pxelinux treats
+	 * this as relative. */
+	check_resolved_url_resource(opt->boot_image,
+			"tftp://host/path/vmlinux");
+	check_resolved_url_resource(opt->initrd,
+			"tftp://host/path/initrd");
+}
diff --git a/test/parser/test-pxe-pathprefix-discover-mac.c b/test/parser/test-pxe-pathprefix-discover-mac.c
index 1e5fa71..3c003fa 100644
--- a/test/parser/test-pxe-pathprefix-discover-mac.c
+++ b/test/parser/test-pxe-pathprefix-discover-mac.c
@@ -37,5 +37,5 @@ void run_test(struct parser_test *test)
 	check_resolved_url_resource(opt->boot_image,
 			"tftp://host/path/to/./kernel");
 	check_resolved_url_resource(opt->initrd,
-			"tftp://host/initrd");
+			"tftp://host/path/to/initrd");
 }
diff --git a/test/parser/test-pxe-pathprefix-discover.c b/test/parser/test-pxe-pathprefix-discover.c
index 9cb44c8..8048961 100644
--- a/test/parser/test-pxe-pathprefix-discover.c
+++ b/test/parser/test-pxe-pathprefix-discover.c
@@ -36,5 +36,5 @@ void run_test(struct parser_test *test)
 	check_resolved_url_resource(opt->boot_image,
 			"tftp://host/path/to/./kernel");
 	check_resolved_url_resource(opt->initrd,
-			"tftp://host/initrd");
+			"tftp://host/path/to/initrd");
 }
diff --git a/test/parser/test-pxe-pathprefix-with-conf.c b/test/parser/test-pxe-pathprefix-with-conf.c
index 57f942d..ce1d600 100644
--- a/test/parser/test-pxe-pathprefix-with-conf.c
+++ b/test/parser/test-pxe-pathprefix-with-conf.c
@@ -34,5 +34,6 @@ void run_test(struct parser_test *test)
 
 	check_resolved_url_resource(opt->boot_image,
 			"tftp://host/path/to/./kernel");
-	check_resolved_url_resource(opt->initrd, "tftp://host/initrd");
+	check_resolved_url_resource(opt->initrd,
+			"tftp://host/path/to/initrd");
 }