Re: [PATCH 1/5 v4] efi_loader: Add device path related functions for initrd via Boot####

On 3/17/21 8:54 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) - 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 | 106 +++++++++++++++++++++++++++++-- 2 files changed, 105 insertions(+), 5 deletions(-)

diff --git a/include/efi_loader.h b/include/efi_loader.h index 68daa1a4a9dc..5d534e69bb59 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -744,6 +744,10 @@ 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);
  

  efi_status_t efi_deserialize_load_option(struct efi_load_option *lo, u8 *data, efi_uintn_t *size); unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data);

diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c index c9315dd45857..1491251e224b 100644 --- a/lib/efi_loader/efi_device_path.c +++ b/lib/efi_loader/efi_device_path.c @@ -282,11 +282,30 @@ struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp) return ndp; }

-struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,

• 		      const struct efi_device_path *dp2)
  

+/** efi_dp_append_or_concatenate() - Append or concatenate two device paths.

Wrong line. You can't put his on the line with /**.

• • 		     Concatenated device path will be separated
    

• • 		     by a sub-type 0xff end node
    

• • @dp1: First device path
• • @dp2: Second device path
• • @concat: If true the two device paths will be concatenated and separated

• • by an end of entrire device path sub-type 0xff end node.
    

• • If true the second device path will be appended to the first and
    

• • terminated by an end node
    

• • Return: concatenated device path or NULL. Caller must free the returned

• •          value
    

Multiple line comments for Return: have to start on a new line or formatting by Sphinx will fail.

• */

+static struct +efi_device_path *efi_dp_append_or_concatenate(const struct efi_device_path *dp1,

• 			      const struct efi_device_path *dp2,
  

• 			      bool concat)
  

  { struct efi_device_path *ret;

• size_t end_size = sizeof(END);

• if (concat)

• end_size = 2 * sizeof(END);
  

  if (!dp1 && !dp2) { /* return an end node */ ret = efi_dp_dup(&END);

@@ -298,18 +317,56 @@ struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1, /* both dp1 and dp2 are non-null */ unsigned sz1 = efi_dp_size(dp1); unsigned sz2 = efi_dp_size(dp2);

• void *p = dp_alloc(sz1 + sz2 + sizeof(END));
  

• void *p = dp_alloc(sz1 + sz2 + end_size);
  

  if (!p) return NULL;

• ret = p;
  

  memcpy(p, dp1, sz1);

• p += sz1;
  

• if (concat) {
  

• 	memcpy(p, &END, sizeof(END));
  

• 	p += sizeof(END);
  

• }
  

• /* the end node of the second device path has to be retained */

• memcpy(p + sz1, dp2, sz2 + sizeof(END));
  

• ret = p;
  

• memcpy(p, dp2, sz2);
  

• p += sz2;
  

• memcpy(p, &END, sizeof(END));
  

  }

  return ret; }

+/** efi_dp_append() - Append a device to an existing device path.

• • @dp1: First device path
• • @dp2: Second device path
• • Return: concatenated device path or NULL. Caller must free the returned

• •          value
    

• */

+struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,

• 		      const struct efi_device_path *dp2)
  

+{

• return efi_dp_append_or_concatenate(dp1, dp2, false);

+}

+/** 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
• • @dp2: 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)
  

+{

• return efi_dp_append_or_concatenate(dp1, dp2, true);

+}

• struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp, const struct efi_device_path *node) {

@@ -1160,3 +1217,42 @@ 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 VenMedia node in a

• •                multi-instance device path that matches
    

• •                a specific GUID. This kind of device paths
    

• •                is found in Boot#### options describing an
    

• •                initrd location
    

• • @load_option: EFI_LOAD_OPTION containing a valid device path

@lo:

I will correct the function comments when merging.

Reviewed-by: Heinrich Schuchardt xypron.glpk@gmx.de

• • @size: size of the discovered device path
• • @guid: guid to search for
• • Return: device path including the VenMedia node or NULL.

• •           Caller must free the returned value
    

• */

+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;
• for (; lo_len >= sizeof(struct efi_device_path);

•     lo_len -= fp->length, fp = (void *)fp + fp->length) {
  

• if (lo_len < 0 || efi_dp_check_length(fp, lo_len) < 0)
  

• 	break;
  

• if (fp->type != DEVICE_PATH_TYPE_MEDIA_DEVICE ||
  

•     fp->sub_type != DEVICE_PATH_SUB_TYPE_VENDOR_PATH)
  

• 	continue;
  

• vendor = (struct efi_device_path_vendor *)fp;
  

• if (!guidcmp(&vendor->guid, &guid))
  

• 	return efi_dp_dup(fp);
  

• }
• log_debug("VenMedia(%pUl) not found in %ls\n", &guid, lo->label);
• return NULL;

+}