[U-Boot] [PATCH v3 11/21] efi_loader: add file/filesys support

Rob Clark
2017-09-13T22:05:34Z

fallback.efi (and probably other things) use UEFI's simple-file-system
protocol and file support to search for OS's to boot.

Signed-off-by: Rob Clark <robdclark@gmail.com>
---
include/efi.h | 2 +
include/efi_api.h | 65 +++++
include/efi_loader.h | 13 +
lib/efi_loader/Makefile | 1 +
lib/efi_loader/efi_disk.c | 32 +++
lib/efi_loader/efi_file.c | 560 ++++++++++++++++++++++++++++++++++++++
lib/efi_loader/efi_image_loader.c | 3 +
7 files changed, 676 insertions(+)
create mode 100644 lib/efi_loader/efi_file.c

diff --git a/include/efi.h b/include/efi.h
index 87b0b43f20..ddd2b96417 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -81,6 +81,8 @@ typedef struct {
#define EFI_IP_ADDRESS_CONFLICT (EFI_ERROR_MASK | 34)
#define EFI_HTTP_ERROR (EFI_ERROR_MASK | 35)

+#define EFI_WARN_DELETE_FAILURE 2
+
typedef unsigned long efi_status_t;
typedef u64 efi_physical_addr_t;
typedef u64 efi_virtual_addr_t;
diff --git a/include/efi_api.h b/include/efi_api.h
index 0c36122107..1aae96355f 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -666,4 +666,69 @@ struct efi_pxe {
struct efi_pxe_mode *mode;
};

+#define EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID \
+ EFI_GUID(0x964e5b22, 0x6459, 0x11d2, \
+ 0x8e, 0x39, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
+#define EFI_FILE_PROTOCOL_REVISION 0x00010000
+
+struct efi_file_handle {
+ u64 rev;
+ efi_status_t (EFIAPI *open)(struct efi_file_handle *file,
+ struct efi_file_handle **new_handle,
+ s16 *file_name, u64 open_mode, u64 attributes);
+ efi_status_t (EFIAPI *close)(struct efi_file_handle *file);
+ efi_status_t (EFIAPI *delete)(struct efi_file_handle *file);
+ efi_status_t (EFIAPI *read)(struct efi_file_handle *file,
+ u64 *buffer_size, void *buffer);
+ efi_status_t (EFIAPI *write)(struct efi_file_handle *file,
+ u64 *buffer_size, void *buffer);
+ efi_status_t (EFIAPI *getpos)(struct efi_file_handle *file,
+ u64 *pos);
+ efi_status_t (EFIAPI *setpos)(struct efi_file_handle *file,
+ u64 pos);
+ efi_status_t (EFIAPI *getinfo)(struct efi_file_handle *file,
+ efi_guid_t *info_type, u64 *buffer_size, void *buffer);
+ efi_status_t (EFIAPI *setinfo)(struct efi_file_handle *file,
+ efi_guid_t *info_type, u64 buffer_size, void *buffer);
+ efi_status_t (EFIAPI *flush)(struct efi_file_handle *file);
+};
+
+#define EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID \
+ EFI_GUID(0x964e5b22, 0x6459, 0x11d2, \
+ 0x8e, 0x39, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
+#define EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_REVISION 0x00010000
+
+struct efi_simple_file_system_protocol {
+ u64 rev;
+ efi_status_t (EFIAPI *open_volume)(struct efi_simple_file_system_protocol *this,
+ struct efi_file_handle **root);
+};
+
+#define EFI_FILE_INFO_GUID \
+ EFI_GUID(0x9576e92, 0x6d3f, 0x11d2, \
+ 0x8e, 0x39, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
+
+#define EFI_FILE_MODE_READ 0x0000000000000001
+#define EFI_FILE_MODE_WRITE 0x0000000000000002
+#define EFI_FILE_MODE_CREATE 0x8000000000000000
+
+#define EFI_FILE_READ_ONLY 0x0000000000000001
+#define EFI_FILE_HIDDEN 0x0000000000000002
+#define EFI_FILE_SYSTEM 0x0000000000000004
+#define EFI_FILE_RESERVED 0x0000000000000008
+#define EFI_FILE_DIRECTORY 0x0000000000000010
+#define EFI_FILE_ARCHIVE 0x0000000000000020
+#define EFI_FILE_VALID_ATTR 0x0000000000000037
+
+struct efi_file_info {
+ u64 size;
+ u64 file_size;
+ u64 physical_size;
+ struct efi_time create_time;
+ struct efi_time last_access_time;
+ struct efi_time modification_time;
+ u64 attribute;
+ s16 file_name[0];
+};
+
#endif
diff --git a/include/efi_loader.h b/include/efi_loader.h
index ec8803f588..b0c1e8fb78 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -65,6 +65,8 @@ extern const efi_guid_t efi_guid_console_control;
extern const efi_guid_t efi_guid_device_path;
extern const efi_guid_t efi_guid_loaded_image;
extern const efi_guid_t efi_guid_device_path_to_text_protocol;
+extern const efi_guid_t efi_simple_file_system_protocol_guid;
+extern const efi_guid_t efi_file_info_guid;

extern unsigned int __efi_runtime_start, __efi_runtime_stop;
extern unsigned int __efi_runtime_rel_start, __efi_runtime_rel_stop;
@@ -140,6 +142,9 @@ int efi_net_register(void);
/* Called by bootefi to make SMBIOS tables available */
void efi_smbios_register(void);

+struct efi_simple_file_system_protocol *
+efi_fs_from_path(struct efi_device_path *fp);
+
/* Called by networking code to memorize the dhcp ack package */
void efi_net_set_dhcp_ack(void *pkt, int len);

@@ -168,6 +173,14 @@ efi_status_t efi_set_timer(struct efi_event *event, enum efi_timer_delay type,
/* Call this to signal an event */
void efi_signal_event(struct efi_event *event);

+/* open file system: */
+struct efi_simple_file_system_protocol *efi_simple_file_system(
+ struct blk_desc *desc, int part, struct efi_device_path *dp);
+
+/* open file from device-path: */
+struct efi_file_handle *efi_file_from_path(struct efi_device_path *fp);
+
+
/* Generic EFI memory allocator, call this to get memory */
void *efi_alloc(uint64_t len, int memory_type);
/* More specific EFI memory allocator, called by EFI payloads */
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index f35e5ce8a8..cce92cfeb5 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -16,6 +16,7 @@ always := $(efiprogs-y)
obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o
obj-y += efi_image_loader.o efi_boottime.o efi_runtime.o efi_console.o
obj-y += efi_memory.o efi_device_path_to_text.o efi_device_path.o
+obj-y += efi_file.o
obj-$(CONFIG_LCD) += efi_gop.o
obj-$(CONFIG_DM_VIDEO) += efi_gop.o
obj-$(CONFIG_PARTITIONS) += efi_disk.o
diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
index 14f3e020c8..9805585eb1 100644
--- a/lib/efi_loader/efi_disk.c
+++ b/lib/efi_loader/efi_disk.c
@@ -31,6 +31,8 @@ struct efi_disk_obj {
struct efi_device_path *dp;
/* partition # */
unsigned part;
+ /* handle to filesys proto (for partition objects) */
+ struct efi_simple_file_system_protocol *volume;
/* Offset into disk for simple partitions */
lbaint_t offset;
/* Internal block device */
@@ -172,6 +174,28 @@ static const struct efi_block_io block_io_disk_template = {
.flush_blocks = &efi_disk_flush_blocks,
};

+/*
+ * Find filesystem from a device-path. The passed in path 'p' probably
+ * contains one or more /File(name) nodes, so the comparison stops at
+ * the first /File() node, and returns the pointer to that via 'rp'.
+ * This is mostly intended to be a helper to map a device-path to an
+ * efi_file_handle object.
+ */
+struct efi_simple_file_system_protocol *
+efi_fs_from_path(struct efi_device_path *fp)
+{
+ struct efi_object *efiobj;
+ struct efi_disk_obj *diskobj;
+
+ efiobj = efi_dp_find_obj(fp, NULL);
+ if (!efiobj)
+ return NULL;
+
+ diskobj = container_of(efiobj, struct efi_disk_obj, parent);
+
+ return diskobj->volume;
+}
+
static void efi_disk_add_dev(const char *name,
const char *if_typename,
struct blk_desc *desc,
@@ -194,6 +218,14 @@ static void efi_disk_add_dev(const char *name,
diskobj->parent.protocols[0].protocol_interface = &diskobj->ops;
diskobj->parent.protocols[1].guid = &efi_guid_device_path;
diskobj->parent.protocols[1].protocol_interface = diskobj->dp;
+ if (part >= 1) {
+ diskobj->volume = efi_simple_file_system(desc, part,
+ diskobj->dp);
+ diskobj->parent.protocols[2].guid =
+ &efi_simple_file_system_protocol_guid;
+ diskobj->parent.protocols[2].protocol_interface =
+ diskobj->volume;
+ }
diskobj->parent.handle = diskobj;
diskobj->ops = block_io_disk_template;
diskobj->ifname = if_typename;
diff --git a/lib/efi_loader/efi_file.c b/lib/efi_loader/efi_file.c
new file mode 100644
index 0000000000..5e1eee5a20
--- /dev/null
+++ b/lib/efi_loader/efi_file.c
@@ -0,0 +1,560 @@
+/*
+ * EFI utils
+ *
+ * Copyright (c) 2017 Rob Clark
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <charset.h>
+#include <efi_loader.h>
+#include <malloc.h>
+#include <fs.h>
+
+struct file_system {
+ struct efi_simple_file_system_protocol base;
+ struct efi_device_path *dp;
+ struct blk_desc *desc;
+ int part;
+};
+#define to_fs(x) container_of(x, struct file_system, base)
+
+struct file_handle {
+ struct efi_file_handle base;
+ struct file_system *fs;
+ loff_t offset; /* current file position/cursor */
+ int isdir;
+
+ /* for reading a directory: */
+ struct fs_dir_stream *dirs;
+ struct fs_dirent *dent;
+
+ char path[0];
+};
+#define to_fh(x) container_of(x, struct file_handle, base)
+
+static const struct efi_file_handle efi_file_handle_protocol;
+
+static char *basename(struct file_handle *fh)
+{
+ char *s = strrchr(fh->path, '/');
+ if (s)
+ return s + 1;
+ return fh->path;
+}
+
+static int set_blk_dev(struct file_handle *fh)
+{
+ return fs_set_blk_dev_with_part(fh->fs->desc, fh->fs->part);
+}
+
+static int is_dir(struct file_handle *fh)
+{
+ struct fs_dir_stream *dirs;
+
+ set_blk_dev(fh);
+ dirs = fs_opendir(fh->path);
+ if (!dirs)
+ return 0;
+
+ fs_closedir(dirs);
+
+ return 1;
+}
+
+/*
+ * Normalize a path which may include either back or fwd slashes,
+ * double slashes, . or .. entries in the path, etc.
+ */
+static int sanitize_path(char *path)
+{
+ char *p ;
+
+ /* backslash to slash: */
+ p = path;
+ while ((p = strchr(p, '\\')))
+ *p++ = '/';
+
+ /* handle double-slashes: */
+ p = path;
+ while ((p = strstr(p, "//"))) {
+ char *src = p + 1;
+ memmove(p, src, strlen(src) + 1);
+ }
+
+ /* handle extra /.'s */
+ p = path;
+ while ((p = strstr(p, "/."))) {
+ /*
+ * You'd be tempted to do this *after* handling ".."s
+ * below to avoid having to check if "/." is start of
+ * a "/..", but that won't have the correct results..
+ * for example, "/foo/./../bar" would get resolved to
+ * "/foo/bar" if you did these two passes in the other
+ * order
+ */
+ if (p[2] == '.') {
+ p += 2;
+ continue;
+ }
+ char *src = p + 2;
+ memmove(p, src, strlen(src) + 1);
+ }
+
+ /* handle extra /..'s: */
+ p = path;
+ while ((p = strstr(p, "/.."))) {
+ char *src = p + 3;
+
+ p--;
+
+ /* find beginning of previous path entry: */
+ while (true) {
+ if (p < path)
+ return -1;
+ if (*p == '/')
+ break;
+ p--;
+ }
+
+ memmove(p, src, strlen(src) + 1);
+ }
+
+ return 0;
+}
+
+/* NOTE: despite what you would expect, 'file_name' is actually a path.
+ * With windoze style backlashes, ofc.
+ */
+static struct efi_file_handle *file_open(struct file_system *fs,
+ struct file_handle *parent, s16 *file_name, u64 mode)
+{
+ struct file_handle *fh;
+ char f0[MAX_UTF8_PER_UTF16] = {0};
+ int plen = 0;
+ int flen = 0;
+
+ if (file_name) {
+ utf16_to_utf8((u8 *)f0, (u16 *)file_name, 1);
+ flen = utf16_strlen((u16 *)file_name);
+ }
+
+ /* we could have a parent, but also an absolute path: */
+ if (f0[0] == '\\') {
+ plen = 0;
+ } else if (parent) {
+ plen = strlen(parent->path) + 1;
+ }
+
+ /* +2 is for null and '/' */
+ fh = calloc(1, sizeof(*fh) + plen + (flen * MAX_UTF8_PER_UTF16) + 2);
+
+ fh->base = efi_file_handle_protocol;
+ fh->fs = fs;
+
+ if (parent) {
+ char *p = fh->path;
+
+ if (plen > 0) {
+ strcpy(p, parent->path);
+ p += plen - 1;
+ *p++ = '/';
+ }
+
+ utf16_to_utf8((u8 *)p, (u16 *)file_name, flen);
+
+ if (sanitize_path(fh->path))
+ goto error;
+
+ /* check if file exists: */
+ if (set_blk_dev(fh))
+ goto error;
+
+ if (!((mode & EFI_FILE_MODE_CREATE) || fs_exists(fh->path)))
+ goto error;
+
+ /* figure out if file is a directory: */
+ fh->isdir = is_dir(fh);
+ } else {
+ fh->isdir = 1;
+ strcpy(fh->path, "");
+ }
+
+ return &fh->base;
+
+error:
+ free(fh);
+ return NULL;
+}
+
+static efi_status_t EFIAPI efi_file_open(struct efi_file_handle *file,
+ struct efi_file_handle **new_handle,
+ s16 *file_name, u64 open_mode, u64 attributes)
+{
+ struct file_handle *fh = to_fh(file);
+
+ EFI_ENTRY("%p, %p, \"%ls\", %llx, %llu", file, new_handle, file_name,
+ open_mode, attributes);
+
+ *new_handle = file_open(fh->fs, fh, file_name, open_mode);
+ if (!*new_handle)
+ return EFI_EXIT(EFI_NOT_FOUND);
+
+ return EFI_EXIT(EFI_SUCCESS);
+}
+
+static efi_status_t file_close(struct file_handle *fh)
+{
+ fs_closedir(fh->dirs);
+ free(fh);
+ return EFI_SUCCESS;
+}
+
+static efi_status_t EFIAPI efi_file_close(struct efi_file_handle *file)
+{
+ struct file_handle *fh = to_fh(file);
+ EFI_ENTRY("%p", file);
+ return EFI_EXIT(file_close(fh));
+}
+
+static efi_status_t EFIAPI efi_file_delete(struct efi_file_handle *file)
+{
+ struct file_handle *fh = to_fh(file);
+ EFI_ENTRY("%p", file);
+ file_close(fh);
+ return EFI_EXIT(EFI_WARN_DELETE_FAILURE);
+}
+
+static efi_status_t file_read(struct file_handle *fh, u64 *buffer_size,
+ void *buffer)
+{
+ loff_t actread;
+
+ if (fs_read(fh->path, (ulong)buffer, fh->offset,
+ *buffer_size, &actread))
+ return EFI_DEVICE_ERROR;
+
+ *buffer_size = actread;
+ fh->offset += actread;
+
+ return EFI_SUCCESS;
+}
+
+static efi_status_t dir_read(struct file_handle *fh, u64 *buffer_size,
+ void *buffer)
+{
+ struct efi_file_info *info = buffer;
+ struct fs_dirent *dent;
+ unsigned required_size;
+
+ if (!fh->dirs) {
+ assert(fh->offset == 0);
+ fh->dirs = fs_opendir(fh->path);
+ if (!fh->dirs)
+ return EFI_DEVICE_ERROR;
+ }
+
+ /*
+ * So this is a bit awkward. Since fs layer is stateful and we
+ * can't rewind an entry, in the EFI_BUFFER_TOO_SMALL case below
+ * we might have to return without consuming the dent.. so we
+ * have to stash it for next call.
+ */
+ if (fh->dent) {
+ dent = fh->dent;
+ fh->dent = NULL;
+ } else {
+ dent = fs_readdir(fh->dirs);
+ }
+
+
+ if (!dent) {
+ /* no more files in directory: */
+ /* workaround shim.efi bug/quirk.. as find_boot_csv()
+ * loops through directory contents, it initially calls
+ * read w/ zero length buffer to find out how much mem
+ * to allocate for the EFI_FILE_INFO, then allocates,
+ * and then calls a 2nd time. If we return size of
+ * zero the first time, it happily passes that to
+ * AllocateZeroPool(), and when that returns NULL it
+ * thinks it is EFI_OUT_OF_RESOURCES. So on first
+ * call return a non-zero size:
+ */
+ if (*buffer_size == 0)
+ *buffer_size = sizeof(*info);
+ else
+ *buffer_size = 0;
+ return EFI_SUCCESS;
+ }
+
+ /* check buffer size: */
+ required_size = sizeof(*info) + 2 * (strlen(dent->name) + 1);
+ if (*buffer_size < required_size) {
+ *buffer_size = required_size;
+ fh->dent = dent;
+ return EFI_BUFFER_TOO_SMALL;
+ }
+
+ *buffer_size = required_size;
+ memset(info, 0, required_size);
+
+ info->size = required_size;
+ info->file_size = dent->size;
+ info->physical_size = dent->size;
+
+ if (dent->type == FS_DT_DIR)
+ info->attribute |= EFI_FILE_DIRECTORY;
+
+ ascii2unicode((u16 *)info->file_name, dent->name);
+
+ fh->offset++;
+
+ return EFI_SUCCESS;
+}
+
+static efi_status_t EFIAPI efi_file_read(struct efi_file_handle *file,
+ u64 *buffer_size, void *buffer)
+{
+ struct file_handle *fh = to_fh(file);
+ efi_status_t ret = EFI_SUCCESS;
+
+ EFI_ENTRY("%p, %p, %p", file, buffer_size, buffer);
+
+ if (set_blk_dev(fh)) {
+ ret = EFI_DEVICE_ERROR;
+ goto error;
+ }
+
+ if (fh->isdir)
+ ret = dir_read(fh, buffer_size, buffer);
+ else
+ ret = file_read(fh, buffer_size, buffer);
+
+error:
+ return EFI_EXIT(ret);
+}
+
+static efi_status_t EFIAPI efi_file_write(struct efi_file_handle *file,
+ u64 *buffer_size, void *buffer)
+{
+ struct file_handle *fh = to_fh(file);
+ efi_status_t ret = EFI_SUCCESS;
+ loff_t actwrite;
+
+ EFI_ENTRY("%p, %p, %p", file, buffer_size, buffer);
+
+ if (set_blk_dev(fh)) {
+ ret = EFI_DEVICE_ERROR;
+ goto error;
+ }
+
+ if (fs_write(fh->path, (ulong)buffer, fh->offset, *buffer_size,
+ &actwrite)) {
+ ret = EFI_DEVICE_ERROR;
+ goto error;
+ }
+
+ *buffer_size = actwrite;
+ fh->offset += actwrite;
+
+error:
+ return EFI_EXIT(ret);
+}
+
+static efi_status_t EFIAPI efi_file_getpos(struct efi_file_handle *file,
+ u64 *pos)
+{
+ struct file_handle *fh = to_fh(file);
+ EFI_ENTRY("%p, %p", file, pos);
+ *pos = fh->offset;
+ return EFI_EXIT(EFI_SUCCESS);
+}
+
+static efi_status_t EFIAPI efi_file_setpos(struct efi_file_handle *file,
+ u64 pos)
+{
+ struct file_handle *fh = to_fh(file);
+ efi_status_t ret = EFI_SUCCESS;
+
+ EFI_ENTRY("%p, %llu", file, pos);
+
+ if (fh->isdir) {
+ if (pos != 0) {
+ ret = EFI_UNSUPPORTED;
+ goto error;
+ }
+ fs_closedir(fh->dirs);
+ fh->dirs = NULL;
+ }
+
+ if (pos == ~0ULL) {
+ loff_t file_size;
+
+ if (set_blk_dev(fh)) {
+ ret = EFI_DEVICE_ERROR;
+ goto error;
+ }
+
+ if (fs_size(fh->path, &file_size)) {
+ ret = EFI_DEVICE_ERROR;
+ goto error;
+ }
+
+ pos = file_size;
+ }
+
+ fh->offset = pos;
+
+error:
+ return EFI_EXIT(ret);
+}
+
+static efi_status_t EFIAPI efi_file_getinfo(struct efi_file_handle *file,
+ efi_guid_t *info_type, u64 *buffer_size, void *buffer)
+{
+ struct file_handle *fh = to_fh(file);
+ efi_status_t ret = EFI_SUCCESS;
+
+ EFI_ENTRY("%p, %p, %p, %p", file, info_type, buffer_size, buffer);
+
+ if (!guidcmp(info_type, &efi_file_info_guid)) {
+ struct efi_file_info *info = buffer;
+ char *filename = basename(fh);
+ unsigned required_size;
+ loff_t file_size;
+
+ /* check buffer size: */
+ required_size = sizeof(*info) + 2 * (strlen(filename) + 1);
+ if (*buffer_size < required_size) {
+ *buffer_size = required_size;
+ ret = EFI_BUFFER_TOO_SMALL;
+ goto error;
+ }
+
+ if (set_blk_dev(fh)) {
+ ret = EFI_DEVICE_ERROR;
+ goto error;
+ }
+
+ if (fs_size(fh->path, &file_size)) {
+ ret = EFI_DEVICE_ERROR;
+ goto error;
+ }
+
+ memset(info, 0, required_size);
+
+ info->size = required_size;
+ info->file_size = file_size;
+ info->physical_size = file_size;
+
+ if (fh->isdir)
+ info->attribute |= EFI_FILE_DIRECTORY;
+
+ ascii2unicode((u16 *)info->file_name, filename);
+ } else {
+ ret = EFI_UNSUPPORTED;
+ }
+
+error:
+ return EFI_EXIT(ret);
+}
+
+static efi_status_t EFIAPI efi_file_setinfo(struct efi_file_handle *file,
+ efi_guid_t *info_type, u64 buffer_size, void *buffer)
+{
+ EFI_ENTRY("%p, %p, %llu, %p", file, info_type, buffer_size, buffer);
+ return EFI_EXIT(EFI_UNSUPPORTED);
+}
+
+static efi_status_t EFIAPI efi_file_flush(struct efi_file_handle *file)
+{
+ EFI_ENTRY("%p", file);
+ return EFI_EXIT(EFI_SUCCESS);
+}
+
+static const struct efi_file_handle efi_file_handle_protocol = {
+ .rev = EFI_FILE_PROTOCOL_REVISION,
+ .open = efi_file_open,
+ .close = efi_file_close,
+ .delete = efi_file_delete,
+ .read = efi_file_read,
+ .write = efi_file_write,
+ .getpos = efi_file_getpos,
+ .setpos = efi_file_setpos,
+ .getinfo = efi_file_getinfo,
+ .setinfo = efi_file_setinfo,
+ .flush = efi_file_flush,
+};
+
+struct efi_file_handle *efi_file_from_path(struct efi_device_path *fp)
+{
+ struct efi_simple_file_system_protocol *v;
+ struct efi_file_handle *f;
+ efi_status_t ret;
+
+ v = efi_fs_from_path(fp);
+ if (!v)
+ return NULL;
+
+ EFI_CALL(ret = v->open_volume(v, &f));
+ if (ret != EFI_SUCCESS)
+ return NULL;
+
+ /* skip over device-path nodes before the file path: */
+ while (fp && !EFI_DP_TYPE(fp, MEDIA_DEVICE, FILE_PATH))
+ fp = efi_dp_next(fp);
+
+ while (fp) {
+ struct efi_device_path_file_path *fdp =
+ container_of(fp, struct efi_device_path_file_path, dp);
+ struct efi_file_handle *f2;
+
+ if (!EFI_DP_TYPE(fp, MEDIA_DEVICE, FILE_PATH)) {
+ printf("bad file path!\n");
+ f->close(f);
+ return NULL;
+ }
+
+ EFI_CALL(ret = f->open(f, &f2, (s16 *)fdp->str,
+ EFI_FILE_MODE_READ, 0));
+ if (ret != EFI_SUCCESS)
+ return NULL;
+
+ fp = efi_dp_next(fp);
+
+ EFI_CALL(f->close(f));
+ f = f2;
+ }
+
+ return f;
+}
+
+static efi_status_t EFIAPI
+efi_open_volume(struct efi_simple_file_system_protocol *this,
+ struct efi_file_handle **root)
+{
+ struct file_system *fs = to_fs(this);
+
+ EFI_ENTRY("%p, %p", this, root);
+
+ *root = file_open(fs, NULL, NULL, 0);
+
+ return EFI_EXIT(EFI_SUCCESS);
+}
+
+struct efi_simple_file_system_protocol *
+efi_simple_file_system(struct blk_desc *desc, int part,
+ struct efi_device_path *dp)
+{
+ struct file_system *fs;
+
+ fs = calloc(1, sizeof(*fs));
+ fs->base.rev = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_REVISION;
+ fs->base.open_volume = efi_open_volume;
+ fs->desc = desc;
+ fs->part = part;
+ fs->dp = dp;
+
+ return &fs->base;
+}
diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
index f961407f50..469acae082 100644
--- a/lib/efi_loader/efi_image_loader.c
+++ b/lib/efi_loader/efi_image_loader.c
@@ -17,6 +17,9 @@ DECLARE_GLOBAL_DATA_PTR;

const efi_guid_t efi_guid_device_path = DEVICE_PATH_GUID;
const efi_guid_t efi_guid_loaded_image = LOADED_IMAGE_GUID;
+const efi_guid_t efi_simple_file_system_protocol_guid =
+ EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
+const efi_guid_t efi_file_info_guid = EFI_FILE_INFO_GUID;

static efi_status_t efi_loader_relocate(const IMAGE_BASE_RELOCATION *rel,
unsigned long rel_size, void *efi_reloc)
--
2.13.5