On Tue, 8 Dec 2020 20:39:50 -0600 Jordan Webb <jor...@getseam.com> wrote:
> When GRUB is loaded as an EFI application, it will copy the EFI > LoadOptions into an environment variable called "efi_load_options" and > export it. I'm not familiar with EFI LoadOptions, however they don't seem to be a string necessarily as implied below. The UEFI 2.9 spec in section 9.1 describes LoadOptions as: A pointer to the image’s binary load options. See the OptionalData parameter in the 1 section of the Boot Manager chapter for information on the source of the LoadOptions data." So this does not sound like necessarily a string and its type is a void pointer. Perhaps there should be a variable "efi_load_options_str" for the stringified representation done below and the variable "efi_load_options" variable should be for the raw binary data. I'm not adamant about this, but I think it makes more sense. Also, this variable(s) should be documented in docs/grub.texi. > > My use case for this is to pass along arguments generated by the > Raspberry Pi's internal bootloader from U-Boot to GRUB to a Linux > kernel, but I think it's something that could be generally useful to > other people doing interesting things in EFI environments. Needs SOB (Signed-off-by). > --- > grub-core/kern/efi/init.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/grub-core/kern/efi/init.c b/grub-core/kern/efi/init.c > index 2c31847bf..29281c3c5 100644 > --- a/grub-core/kern/efi/init.c > +++ b/grub-core/kern/efi/init.c > @@ -17,6 +17,7 @@ > * along with GRUB. If not, see <http://www.gnu.org/licenses/>. > */ > > +#include <grub/charset.h> > #include <grub/efi/efi.h> > #include <grub/efi/console.h> > #include <grub/efi/disk.h> > @@ -31,6 +32,10 @@ grub_addr_t grub_modbase; > void > grub_efi_init (void) > { > + grub_efi_loaded_image_t *image = NULL; > + int len; > + char *load_options; > + > grub_modbase = grub_efi_modules_addr (); > /* First of all, initialize the console so that GRUB can display > messages. */ > @@ -43,6 +48,14 @@ grub_efi_init (void) > 0, 0, 0, NULL); > > grub_efidisk_init (); > + > + /* Copy EFI load options into environment */ > + image = grub_efi_get_loaded_image (grub_efi_image_handle); Should only do the following if the above does not error. > + len = image->load_options_size / sizeof (grub_efi_char16_t); > + load_options = grub_malloc (len * sizeof (char)); Error check that grub_malloc returns a good pointer. Also, I believe it should be (len + 1) so that the NULL byte written below is not out of bounds. > + *grub_utf16_to_utf8 ((grub_uint8_t *) load_options, image->load_options, > len) = '\0'; > + grub_env_set("efi_load_options", load_options); > + grub_env_export("efi_load_options"); Space before '(' for both lines above. Glenn > } > > void (*grub_efi_net_config) (grub_efi_handle_t hnd, _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
