On Wed, May 08, 2024 at 07:24:01PM +0800, Weizhao Ouyang wrote:
> diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
> index de0d49ebebda..919e3cba071b 100644
> --- a/lib/efi_loader/efi_capsule.c
> +++ b/lib/efi_loader/efi_capsule.c
> @@ -922,6 +922,105 @@ static bool device_is_present_and_system_part(struct 
> efi_device_path *dp)
>       return true;
>  }
>  
> +/**
> + * get_esp_from_boot_option_file_path - get the expand device path
> + *
> + * Get a possible efi system partition by expanding a boot option
> + * file path.
> + *
> + * @boot_dev The device path pointing to a boot option
> + * Return:   The full ESP device path or NULL if fail
> + */
> +static struct efi_device_path *get_esp_from_boot_option_file_path(struct 
> efi_device_path *boot_dev)
> +{
> +     efi_status_t ret = EFI_SUCCESS;
> +     efi_handle_t handle;
> +     struct efi_device_path *dp = boot_dev;
> +     struct efi_device_path *full_path = NULL;
> +
> +     ret = 
> EFI_CALL(efi_locate_device_path(&efi_simple_file_system_protocol_guid,
> +                                           &dp,
> +                                           &handle));
> +     if (ret != EFI_SUCCESS)
> +             ret = EFI_CALL(efi_locate_device_path(&efi_block_io_guid, &dp, 
> &handle));
> +
> +     /* Expand Media Device Path */
> +     if (ret == EFI_SUCCESS && EFI_DP_TYPE(dp, END, END)) {

Flip this around.  Always do failure handling.  Never do success
handling.  full_path is always NULL.  Just return that.  Delete
the variable.

        if (ret != EFI_SUCCESS ||
            !EFI_DP_TYPE(dp, END, END))
                return NULL;


> +             struct efi_device_path *temp_dp;
> +             struct efi_block_io *block_io;
> +             void *buffer;
> +             efi_handle_t *simple_file_system_handle;
> +             efi_uintn_t number_handles, index;
> +             u32 size;
> +             u32 temp_size;
> +
> +             temp_dp = boot_dev;
> +             ret = 
> EFI_CALL(efi_locate_device_path(&efi_simple_file_system_protocol_guid,
> +                                                   &temp_dp,
> +                                                   &handle));
> +             /*
> +              * For device path pointing to simple file system, it only 
> expands to one
> +              * full path
> +              */
> +             if (ret == EFI_SUCCESS && EFI_DP_TYPE(temp_dp, END, END)) {

"Always" was hyperbole.  This success handling is fine.

> +                     if (device_is_present_and_system_part(temp_dp))
> +                             return temp_dp;
> +             }
> +
> +             /*
> +              * For device path only pointing to the removable device 
> handle, try to
> +              * search all its children handles
> +              */
> +             ret = EFI_CALL(efi_locate_device_path(&efi_block_io_guid, 
> &temp_dp, &handle));

ret is not used.  Delete.

> +             EFI_CALL(efi_connect_controller(handle, NULL, NULL, true));
> +
> +             /* Align with edk2, issue a dummy read to the device to check 
> the device change */
> +             ret = EFI_CALL(efi_handle_protocol(handle, &efi_block_io_guid, 
> (void **)&block_io));
> +             if (ret == EFI_SUCCESS) {

        if (ret != EFI_SUCCESS)
                return NULL;

> +                     buffer = memalign(block_io->media->io_align, 
> block_io->media->block_size);
> +                     if (buffer) {

        if (!buffer)
                return NULL;


> +                             ret = EFI_CALL(block_io->read_blocks(block_io,
> +                                                                  
> block_io->media->media_id,
> +                                                                  0,
> +                                                                  
> block_io->media->block_size,
> +                                                                  buffer));

Delete the unused "ret = " assignment.

> +                             free(buffer);
> +                     } else {
> +                             return full_path;
> +                     }
> +             } else {
> +                     return full_path;
> +             }
> +
> +             /* detect the default boot file from removable media */
> +             size = efi_dp_size(boot_dev) - sizeof(struct efi_device_path);
> +             EFI_CALL(efi_locate_handle_buffer(BY_PROTOCOL,
> +                                               
> &efi_simple_file_system_protocol_guid,
> +                                               NULL,
> +                                               &number_handles,
> +                                               &simple_file_system_handle));
> +             for (index = 0; index < number_handles; index++) {
> +                     
> EFI_CALL(efi_handle_protocol(simple_file_system_handle[index],
> +                                                  &efi_guid_device_path,
> +                                                  (void **)&temp_dp));
> +
> +                     log_debug("Search ESP %pD\n", temp_dp);
> +                     temp_size = efi_dp_size(temp_dp) - sizeof(struct 
> efi_device_path);
> +                     if (size <= temp_size && !memcmp(temp_dp, boot_dev, 
> size)) {
> +                             if (device_is_present_and_system_part(temp_dp)) 
> {

You could combine these conditions:

                if (size <= temp_size &&
                    memcmp(temp_dp, boot_dev, size) == 0 &&
                    device_is_present_and_system_part(temp_dp)) {
                        efi_free_pool(simple_file_system_handle);
                        return temp_dp;
                }


> +                                     
> efi_free_pool(simple_file_system_handle);
> +                                     return temp_dp;
> +                             }
> +                     }
> +             }
> +
> +             if (simple_file_system_handle)
> +                     efi_free_pool(simple_file_system_handle);
> +     }
> +
> +     return full_path;
> +}
> +
>  /**
>   * find_boot_device - identify the boot device
>   *
> @@ -938,6 +1037,7 @@ static efi_status_t find_boot_device(void)
>       int i, num;
>       struct efi_simple_file_system_protocol *volume;
>       struct efi_device_path *boot_dev = NULL;
> +     struct efi_device_path *full_path = NULL;

No need to initialize this to NULL, it disables static checker warnings
for uninitialized variables so it can lead to bugs.

>       efi_status_t ret;
>  
>       /* find active boot device in BootNext */
> @@ -961,8 +1061,14 @@ static efi_status_t find_boot_device(void)
>                       if (device_is_present_and_system_part(boot_dev)) {
>                               goto found;
>                       } else {
> -                             efi_free_pool(boot_dev);
> -                             boot_dev = NULL;
> +                             full_path = 
> get_esp_from_boot_option_file_path(boot_dev);
> +                             if (full_path) {
> +                                     boot_dev = full_path;

Later, we free full_path but do we ever free the original boot_dev?

> +                                     goto found;
> +                             } else {
> +                                     efi_free_pool(boot_dev);
> +                                     boot_dev = NULL;
> +                             }

Better to delete indenting where you can:

                        full_path = 
get_esp_from_boot_option_file_path(boot_dev);
                        if (full_path) {
                                boot_dev = full_path;
                                goto found;
                        }
                        efi_free_pool(boot_dev);
                        boot_dev = NULL;

regards,
dan carpenter


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