Support loading kernels by relative path

Allow specifying paths to files (kernel images, initrds) relative to the
boot drive instead of hard-coding a disk path / number in the efilinux.cfg.

Signed-off-by: Steve Langasek <steve.langasek@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

4 files changed, 26 insertions, 11 deletions

diff --git a/entry.c b/entry.c
index 5e165b1..b5155af 100644
--- a/entry.c
+++ b/entry.c
@@ -323,7 +323,7 @@ read_config_file(EFI_LOADED_IMAGE *image, CHAR16 **options,
 	if (err != TRUE)
 		return FALSE;
 
-	err = file_open(path, &file);
+	err = file_open(image, path, &file);
 	if (err != EFI_SUCCESS)
 		return FALSE;
 
diff --git a/fs/fs.c b/fs/fs.c
index 8a45442..477afd1 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -73,7 +73,7 @@ handle_to_dev(EFI_HANDLE *handle)
  * @file: used to return a pointer to the allocated file on success
  */
 EFI_STATUS
-file_open(CHAR16 *name, struct file **file)
+file_open(EFI_LOADED_IMAGE *image, CHAR16 *name, struct file **file)
 {
 	EFI_FILE_HANDLE fh;
 	struct file *f;
@@ -91,10 +91,19 @@ file_open(CHAR16 *name, struct file **file)
 			break;
 	}
 
-	if (!name[dev_len] || !dev_len)
-		goto notfound;
+	if (!name[dev_len] || !dev_len) {
+		dev_len = 0;
+		if (!image)
+			goto notfound;
+
+		i = handle_to_dev(image->DeviceHandle);
+		if (i < 0 || i >= nr_fs_devices)
+			goto notfound;
 
-	name[dev_len] = 0;
+		f->handle = fs_devices[i].fh;
+		goto found;
+	} else
+		name[dev_len++] = 0;
 
 	if (name[0] >= '0' && name[0] <= '9') {
 		i = Atoi(name);
@@ -126,7 +135,7 @@ file_open(CHAR16 *name, struct file **file)
 
 found:
 	/* Strip the device name */
-	filename = name + dev_len + 1;
+	filename = name + dev_len;
 
 	/* skip any path separators */
 	while (*filename == ':' || *filename == '\\')
diff --git a/fs/fs.h b/fs/fs.h
index 0f76d0c..4a6c71f 100644
--- a/fs/fs.h
+++ b/fs/fs.h
@@ -98,7 +98,7 @@ file_size(struct file *f, UINT64 *size)
 	return EFI_SUCCESS;
 }
 
-extern EFI_STATUS file_open(CHAR16 *name, struct file **file);
+extern EFI_STATUS file_open(EFI_LOADED_IMAGE *image, CHAR16 *name, struct file **file);
 extern EFI_STATUS file_close(struct file *f);
 
 extern void list_boot_devices(void);
diff --git a/loaders/bzimage/bzimage.c b/loaders/bzimage/bzimage.c
index 8789876..d323874 100644
--- a/loaders/bzimage/bzimage.c
+++ b/loaders/bzimage/bzimage.c
@@ -54,7 +54,7 @@ struct initrd {
 	struct file *file;
 };
 
-static void parse_initrd(struct boot_params *buf, char *cmdline)
+static void parse_initrd(EFI_LOADED_IMAGE *image, struct boot_params *buf, char *cmdline)
 {
 	EFI_PHYSICAL_ADDRESS addr;
 	struct initrd *initrds;
@@ -116,7 +116,7 @@ static void parse_initrd(struct boot_params *buf, char *cmdline)
 
 		*n = '\0';
 
-		err = file_open(filename, &rdfile);
+		err = file_open(image, filename, &rdfile);
 		if (err != EFI_SUCCESS)
 			goto close_handles;
 
@@ -174,6 +174,7 @@ load_kernel(EFI_HANDLE image, CHAR16 *name, char *_cmdline)
 	EFI_PHYSICAL_ADDRESS pref_address;
 	struct boot_params *boot_params;
 	EFI_MEMORY_DESCRIPTOR *map_buf;
+	EFI_LOADED_IMAGE *info = NULL;
 	struct e820_entry *e820_map;
 	UINT64 setup_sz, init_size;
 	struct boot_params *buf;
@@ -187,7 +188,12 @@ load_kernel(EFI_HANDLE image, CHAR16 *name, char *_cmdline)
 	UINT64 size;
 	int i, j = 0;
 
-	err = file_open(name, &file);
+	err = handle_protocol(image, &LoadedImageProtocol, (void **)&info);
+	if (err != EFI_SUCCESS)
+		info = NULL;
+
+	err = file_open(info, name, &file);
+
 	if (err != EFI_SUCCESS)
 		goto out;
 
@@ -279,7 +285,7 @@ load_kernel(EFI_HANDLE image, CHAR16 *name, char *_cmdline)
 	cmdline = (char *)(UINTN)addr;
 	memcpy(cmdline, _cmdline, strlen(_cmdline) + 1);
 
-	parse_initrd(buf, cmdline);
+	parse_initrd(info, buf, cmdline);
 
 	buf->hdr.cmd_line_ptr = (UINT32)(UINTN)cmdline;