discover: Add support for checking directories in parser API

This change adds a function to the parser API:

  int parser_check_dir(struct discover_context *ctx,
  		struct discover_device *dev, const char *dirname)

- which allows parsers to check for the presence of a directory (path of
'dirname') on the device ('dev'). We use this in the GRUB2 parser to
implement the `test -d` check.

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

3 files changed, 35 insertions, 0 deletions

diff --git a/discover/grub2/builtins.c b/discover/grub2/builtins.c
index 7511076..6ada2a6 100644
--- a/discover/grub2/builtins.c
+++ b/discover/grub2/builtins.c
@@ -154,6 +154,15 @@ static bool builtin_test_op_file(struct grub2_script *script, char op,
 	return result;
 }
 
+static bool builtin_test_op_dir(struct grub2_script *script, char op,
+		const char *dir)
+{
+	if (op != 'd')
+		return false;
+
+	return parser_check_dir(script->ctx, script->ctx->device, dir) == 0;
+}
+
 static bool builtin_test_op(struct grub2_script *script,
 		int argc, char **argv, int *consumed)
 {
@@ -207,6 +216,11 @@ static bool builtin_test_op(struct grub2_script *script,
 			*consumed = 2;
 			return builtin_test_op_file(script, op[1], a1);
 		}
+
+		if (!strcmp(op, "-d")) {
+			*consumed = 2;
+			return builtin_test_op_dir(script, op[1], a1);
+		}
 	}
 
 	op = argv[0];
diff --git a/discover/parser.c b/discover/parser.c
index 21b48de..74b2559 100644
--- a/discover/parser.c
+++ b/discover/parser.c
@@ -49,6 +49,25 @@ int parser_request_file(struct discover_context *ctx,
 	return rc;
 }
 
+int parser_check_dir(struct discover_context *ctx,
+		struct discover_device *dev, const char *dirname)
+{
+	struct stat statbuf;
+	char *path;
+	int rc;
+
+	if (!dev->mount_path)
+		return -1;
+
+	path = local_path(ctx, dev, dirname);
+
+	rc = stat(path, &statbuf);
+	if (!rc)
+		return -1;
+
+	return S_ISDIR(statbuf.st_mode) ? 0 : -1;
+}
+
 int parser_replace_file(struct discover_context *ctx,
 		struct discover_device *dev, const char *filename,
 		char *buf, int len)
diff --git a/discover/parser.h b/discover/parser.h
index 970d72c..e0e8dc6 100644
--- a/discover/parser.h
+++ b/discover/parser.h
@@ -62,5 +62,7 @@ int parser_replace_file(struct discover_context *ctx,
 		char *buf, int len);
 int parser_request_url(struct discover_context *ctx, struct pb_url *url,
 		char **buf, int *len);
+int parser_check_dir(struct discover_context *ctx,
+		struct discover_device *dev, const char *dirname);
 
 #endif /* _PARSER_H */