On 3/5/21 11:22 PM, Ilias Apalodimas wrote:
On the following patches we allow for an initrd path to be stored in Boot#### variables. Specifically we encode in the FIlePathList[] of the EFI_LOAD_OPTIONS for each Boot#### variable.
The FilePathList[] array looks like this: kernel - 0xff - VenMedia(initrd GUID) - 0x01 - initrd1 - 0x01 initrd2 -0xff So let's add the relevant functions to concatenate and retrieve a device path based on a Vendor GUID.
Signed-off-by: Ilias Apalodimas ilias.apalodimas@linaro.org
include/efi_loader.h | 4 ++ lib/efi_loader/efi_device_path.c | 72 ++++++++++++++++++++++++++++++++ 2 files changed, 76 insertions(+)
diff --git a/include/efi_loader.h b/include/efi_loader.h index f470bbd636f4..eb11a8c7d4b1 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -738,6 +738,10 @@ struct efi_load_option { const u8 *optional_data; };
+struct efi_device_path *efi_dp_from_lo(struct efi_load_option *lo,
efi_uintn_t *size, efi_guid_t guid);+struct efi_device_path *efi_dp_concat(const struct efi_device_path *dp1,
const struct efi_device_path *dp2);diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c index c9315dd45857..cf1321828e87 100644 --- a/lib/efi_loader/efi_device_path.c +++ b/lib/efi_loader/efi_device_path.c @@ -310,6 +310,41 @@ struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1, return ret; }
+/** efi_dp_concat() - Concatenate 2 device paths. The final device path will contain
two device paths separated by and end node (0xff).
- @dp1: First device path
- @size: Second device path
- Return: concatenated device path or NULL. Caller must free the returned value
- */
+struct efi_device_path *efi_dp_concat(const struct efi_device_path *dp1,
const struct efi_device_path *dp2)+{
- struct efi_device_path *ret;
- efi_uintn_t sz1, sz2;
- void *p;
- if (!dp1 || !dp2)
return NULL;- sz1 = efi_dp_size(dp1);
- sz2 = efi_dp_size(dp2);
- p = dp_alloc(sz1 + sz2 + (2 * sizeof(END)));
- /* both dp1 and dp2 are non-null */
- if (!p)
return NULL;- ret = p;
- memcpy(p, dp1, sz1);
- p += sz1;
- memcpy(p, &END, sizeof(END));
- p += sizeof(END);
- memcpy(p, dp2, sz2);
- p += sz2;
- memcpy(p, &END, sizeof(END));
- return ret;
+}
- struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp, const struct efi_device_path *node) {
@@ -1160,3 +1195,40 @@ ssize_t efi_dp_check_length(const struct efi_device_path *dp, dp = (const struct efi_device_path *)((const u8 *)dp + len); } }
+/**
- efi_dp_from_lo() - Get the instance of a Vendor Device Path
in a multi-instance device path that matches
a specific GUID
The description does make it clear that you are looking for a VenMedia() node.
Please, describe what the function is good for (find the device path for an initrd or dtb in a load option).
- @load_option: device paths to search
- @size: size of the discovered device path
- @guid: guid to search for
- Return: device path or NULL. Caller must free the returned value
Please, keep the text aligned.
Do we need a copy? Isn't a pointer good enough?
- */
+struct +efi_device_path *efi_dp_from_lo(struct efi_load_option *lo,
efi_uintn_t *size, efi_guid_t guid)+{
- struct efi_device_path *fp = lo->file_path;
- struct efi_device_path_vendor *vendor;
- int lo_len = lo->file_path_length;
- while (lo_len) {
lo_len must be at least sizeof(struct efi_device_path).
if (fp->type != DEVICE_PATH_TYPE_MEDIA_DEVICE ||fp->sub_type != DEVICE_PATH_SUB_TYPE_VENDOR_PATH) {lo_len -= fp->length;
Could the last device path in the array be followed by zero bytes for padding? Should we check that fp->length >= sizeof(struct efi_device_path)?
fp = (void *)fp + fp->length;
Please, avoid code duplication.
E.g.
for (; lo_len >= sizeof(struct efi_device_path); lo_len -= fp->length, fp = (void *)fp + fp->length) {
continue;}vendor = (struct efi_device_path_vendor *)fp;if (!guidcmp(&vendor->guid, &guid))return efi_dp_dup(fp);
Should we strip of the VenMedia() node here?
Best regards
Heinrich
lo_len -= fp->length;fp = (void *)fp + fp->length;- }
- return NULL;
+}