From 2dd1e77aef18cdc286ae5e366fdb410a9f02b230 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Tue, 5 Oct 2021 13:58:03 +0200
Subject: [efi] local: Allow loading from any volume by using file://*/...

---
 src/interface/efi/efi_local.c | 89 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 82 insertions(+), 7 deletions(-)

(limited to 'src/interface')

diff --git a/src/interface/efi/efi_local.c b/src/interface/efi/efi_local.c
index 4ebca5726..64e0addd0 100644
--- a/src/interface/efi/efi_local.c
+++ b/src/interface/efi/efi_local.c
@@ -294,6 +294,62 @@ static int efi_local_open_root ( struct efi_local *local, EFI_HANDLE device,
 	return rc;
 }
 
+/**
+ * Open root filesystem of specified volume by index
+ *
+ * @v local		Local file
+ * @v index		Volume index
+ * @ret rc		Return status code
+ */
+static int efi_local_open_volume_index ( struct efi_local *local,
+				   UINTN index ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	EFI_GUID *protocol = &efi_simple_file_system_protocol_guid;
+	EFI_FILE_PROTOCOL *root;
+	EFI_HANDLE *handles;
+	EFI_HANDLE device;
+	UINTN num_handles;
+	EFI_STATUS efirc;
+	int rc;
+
+	/* Locate all filesystem handles */
+	if ( ( efirc = bs->LocateHandleBuffer ( ByProtocol, protocol,
+						NULL, &num_handles,
+						&handles ) ) != 0 ) {
+		rc = -EEFI ( efirc );
+		DBGC ( local, "LOCAL %p could not enumerate handles: "
+				 "%s\n", local, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Find matching handle */
+	if ( index >= num_handles ) {
+		rc = -ENOENT;
+	} else {
+		/* Get this device handle */
+		device = handles[index];
+
+		/* Open root directory */
+		if ( ( rc = efi_local_open_root ( local, device, &root ) ) == 0 && root ) {
+			local->root = root;
+			rc = 0;
+		} else {
+			rc = -EACCES;
+		}
+	}
+
+	/* Free handles, if applicable */
+	bs->FreePool ( handles );
+
+	/* Fail if we found no matching handle */
+	if ( ! local->root ) {
+		DBGC ( local, "LOCAL %p found no matching device with index %u\n",
+				local, (unsigned int)index );
+	}
+
+	return rc;
+}
+
 /**
  * Open root filesystem of specified volume
  *
@@ -534,7 +590,7 @@ static int efi_local_open ( struct interface *xfer, struct uri *uri ) {
 	struct efi_local *local;
 	const char *volume;
 	const char *path;
-	int rc;
+	int rc, vol;
 
 	/* Parse URI */
 	volume = ( ( uri->host && uri->host[0] ) ? uri->host : NULL );
@@ -551,13 +607,32 @@ static int efi_local_open ( struct interface *xfer, struct uri *uri ) {
 	process_init_stopped ( &local->process, &efi_local_process_desc,
 			       &local->refcnt );
 
-	/* Open specified volume */
-	if ( ( rc = efi_local_open_volume ( local, volume ) ) != 0 )
-		goto err_open_root;
+	if ( volume && strcmp ( volume, "*" ) == 0 ) {
+		/* Open on any volume */
+		vol = 0;
+		while ( ( rc = efi_local_open_volume_index ( local, vol++ ) ) != -ENOENT ) {
+			if ( rc != 0 )
+				continue;
+			/* Open specified path */
+			if ( ( rc = efi_local_open_path ( local, path ) ) != 0 ) {
+				local->root->Close ( local->root );
+				local->root = NULL;
+				continue;
+			}
+			/* Success */
+			break;
+		}
+		if ( rc != 0 )
+			goto err_open_root;
+	} else {
+		/* Open specified volume */
+		if ( ( rc = efi_local_open_volume ( local, volume ) ) != 0 )
+			goto err_open_root;
 
-	/* Open specified path */
-	if ( ( rc = efi_local_open_path ( local, path ) ) != 0 )
-		goto err_open_file;
+		/* Open specified path */
+		if ( ( rc = efi_local_open_path ( local, path ) ) != 0 )
+			goto err_open_file;
+	}
 
 	/* Get length of file */
 	if ( ( rc = efi_local_len ( local ) ) != 0 )
-- 
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