shithub: riscv

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ref: bbc35cc01b3632fe345244a5a366dd5e80755265
parent: 045530aed25b515d501e7502af2c42ecf66d6dd2
author: cinap_lenrek <[email protected]>
date: Fri Jun 5 01:09:22 EDT 2015 

9boot: look for plan9.ini in all filesystems accessible to efi to find plan9 partition

try the handle buffer in reverse order looking for plan9.ini
to find plan9 partition (9fat). when that fails, we'll default
to the first handle which should be the esp.


--- a/sys/src/boot/efi/fs.c
+++ b/sys/src/boot/efi/fs.c
@@ -87,23 +87,48 @@
 fsinit(void **pf)
 {
 	EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *fs;
+	EFI_FILE_PROTOCOL *root;
+	EFI_HANDLE *Handles;
+	void *f;
+	UINTN Count;
+	int i;
 
-	fs = nil;
-	fsroot = nil;
-	if(eficall(ST->BootServices->LocateProtocol,
-		&EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID, nil, &fs))
+	Count = 0;
+	Handles = nil;
+	if(eficall(ST->BootServices->LocateHandleBuffer,
+		ByProtocol, &EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID, nil, &Count, &Handles))
 		return -1;
-	if(eficall(fs->OpenVolume, fs, &fsroot)){
-		fsroot = nil;
-		return -1;
+
+	/*
+	 * assuming the ESP is the first entry in the handle buffer, so go backwards
+	 * to scan for plan9.ini in other (9fat) filesystems first. if nothing is found
+	 * we'll be defaulting to the ESP.
+	 */
+	fsroot = nil;
+	for(i=Count-1; i>=0; i--){
+		root = nil;
+		fs = nil;
+		if(eficall(ST->BootServices->HandleProtocol,
+			Handles[i], &EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID, &fs))
+			continue;
+		if(eficall(fs->OpenVolume, fs, &root))
+			continue;
+		fsroot = root;
+		f = fsopen("/plan9.ini");
+		if(f != nil){
+			if(pf != nil)
+				*pf = f;
+			else
+				fsclose(f);
+			break;
+		}
 	}
+	if(fsroot == nil)
+		return -1;
 
 	read = fsread;
 	close = fsclose;
 	open = fsopen;
-
-	if(pf != nil)
-		*pf = fsopen("/plan9.ini");
 
 	return 0;
 }