[meta-intel] [PATCH RFC] systemd-boot_%.bbappend: Add stub command line modifications patch

Cal Sullivan california.l.sullivan at intel.com
Wed Jun 14 18:53:28 PDT 2017


This was supposed to be in reply to Patrick's comment on patch 1/4 of my 
previous set, but I missed a letter at the end of the message ID. Oops.

---
Cal

On 06/14/2017 06:47 PM, California Sullivan wrote:
> Allows you to modify the command line when called from EFI shell
> instead of the entire command line getting replaced.
>
> Signed-off-by: California Sullivan <california.l.sullivan at intel.com>
> ---
> I liked this idea so I gave it a shot. Let me know what you think.
> Commit message is a WIP. Its getting late but I'd like some feedback.
>
>   ...ub-allow-smarter-command-line-modificatio.patch | 132 +++++++++++++++++++++
>   .../systemd-boot/systemd-boot_%.bbappend           |   1 +
>   2 files changed, 133 insertions(+)
>   create mode 100644 common/recipes-bsp/systemd-boot/systemd-boot/0001-boot-efi-stub-allow-smarter-command-line-modificatio.patch
>
> diff --git a/common/recipes-bsp/systemd-boot/systemd-boot/0001-boot-efi-stub-allow-smarter-command-line-modificatio.patch b/common/recipes-bsp/systemd-boot/systemd-boot/0001-boot-efi-stub-allow-smarter-command-line-modificatio.patch
> new file mode 100644
> index 0000000..9cc92c9
> --- /dev/null
> +++ b/common/recipes-bsp/systemd-boot/systemd-boot/0001-boot-efi-stub-allow-smarter-command-line-modificatio.patch
> @@ -0,0 +1,132 @@
> +From 47a4ce351911625f227b8b29d9c307d5c32fd32f Mon Sep 17 00:00:00 2001
> +From: California Sullivan <california.l.sullivan at intel.com>
> +Date: Wed, 14 Jun 2017 17:33:30 -0700
> +Subject: [PATCH] boot: efi: stub: allow smarter command line modifications
> +
> +Currently, the command line is replaced with anything that ends up in
> +LoadOptions. LoadOptions gets populated by the firmware, and EFI shell
> +command line information when running a binary. This includes the name
> +of the binary itself, so it will usually break booting from the EFI
> +shell.
> +
> +Instead, have LoadOptions modify the command line in the following way:
> +
> +bootx64 root=/dev/sda -> prepend the command line (default)
> +bootx64 ^console=/dev/tty0 -> prepend the command line (explicit)
> +bootx64 $console=/dev/tty0 -> append the command line
> +bootx64 !console=/dev/tty0 root=/dev/sda -> replace the command line
> +
> +The '^', '$' and '!' characters act as sentinel values, telling the EFI
> +stub how to handle LoadOptions values, as well as indicating where
> +command line modifications in LoadOptions should begin.
> +
> +Note that with the default case, bootx64 will end up in the kernel
> +command line, as we use the sentinel values to decide where to begin the
> +command line modifications.
> +
> +Signed-off-by: California Sullivan <california.l.sullivan at intel.com>
> +---
> + src/boot/efi/stub.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++---
> + 1 file changed, 78 insertions(+), 4 deletions(-)
> +
> +diff --git a/src/boot/efi/stub.c b/src/boot/efi/stub.c
> +index 74e95fd..a4b34a2 100644
> +--- a/src/boot/efi/stub.c
> ++++ b/src/boot/efi/stub.c
> +@@ -93,15 +93,89 @@ EFI_STATUS efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *sys_table) {
> +         /* if we are not in secure boot mode, accept a custom command line and replace the built-in one */
> +         if (!secure && loaded_image->LoadOptionsSize > 0 && *(CHAR16 *)loaded_image->LoadOptions != 0) {
> +                 CHAR16 *options;
> ++                CHAR8 mode;
> +                 CHAR8 *line;
> ++                UINTN options_len;
> ++                UINTN total_len;
> +                 UINTN i;
> ++                UINTN j;
> ++                UINTN k;
> +
> +                 options = (CHAR16 *)loaded_image->LoadOptions;
> +-                cmdline_len = (loaded_image->LoadOptionsSize / sizeof(CHAR16)) * sizeof(CHAR8);
> +-                line = AllocatePool(cmdline_len);
> +-                for (i = 0; i < cmdline_len; i++)
> +-                        line[i] = options[i];
> ++                options_len = (loaded_image->LoadOptionsSize / sizeof(CHAR16)) * sizeof(CHAR8);
> ++
> ++                mode = '?';
> ++                /* walk through options to find sentinel values indicating alternative modes
> ++                * also use this index to begin the command line changes
> ++                * this lets us avoid adding the binary name to the command line */
> ++                for(i = 0; i < options_len; i++) {
> ++                        if (options[i] == '$' ||
> ++                            options[i] == '!' ||
> ++                            options[i] == '^') {
> ++                                mode = options[i];
> ++                                break;
> ++                        }
> ++                }
> ++
> ++                switch(mode) {
> ++
> ++                /* append to the cmdline */
> ++                case '$':
> ++                        total_len = cmdline_len + options_len - i + 1;
> ++                        i++;
> ++                        line = AllocatePool(total_len);
> ++                        for (j = 0; j < cmdline_len; j++)
> ++                                line[j] = cmdline[j];
> ++
> ++                        line[j++] = ' ';
> ++
> ++                        for (k = 0; i + k < options_len && j + k < total_len; k++)
> ++                                line[j + k] = options[i + k];
> ++
> ++                        break;
> ++
> ++                /* replace the cmdline */
> ++                case '!':
> ++                        total_len = options_len - i;
> ++                        i++;
> ++                        line = AllocatePool(total_len);
> ++                        for (j = 0; i + j < options_len; j++)
> ++                                line[j] = options[i + j];
> ++                        break;
> ++
> ++                /* prepend to cmdline */
> ++                case '^':
> ++                        total_len = cmdline_len + options_len - i;
> ++                        i++;
> ++                        line = AllocatePool(total_len);
> ++
> ++                        /* Ignore null character at last index */
> ++                        for (j = 0; i + j < options_len - 1; j++)
> ++                                line[j] = options[i + j];
> ++
> ++                        line[j++] = ' ';
> ++
> ++                        for (k = 0; k < cmdline_len && j + k < total_len; k++)
> ++                                line[j + k] = cmdline[k];
> ++                        break;
> ++
> ++                /* prepend anyway, but don't get rid of binary name since we couldn't find a sentinel */
> ++                default:
> ++                        total_len = cmdline_len + options_len;
> ++                        line = AllocatePool(total_len);
> ++                        /* Ignore null character at last index */
> ++                        for (i = 0; i < options_len - 1; i++)
> ++                                line[i] = options[i];
> ++
> ++                        line[i++] = ' ';
> ++
> ++                        for (j = 0; j < cmdline_len && i + j < total_len; j++)
> ++                                line[i + j] = cmdline[j];
> ++                        break;
> ++                }
> ++
> +                 cmdline = line;
> ++                cmdline_len = total_len;
> +
> + #ifdef SD_BOOT_LOG_TPM
> +                 /* Try to log any options to the TPM, escpecially manually edited options */
> +--
> +2.5.5
> +
> diff --git a/common/recipes-bsp/systemd-boot/systemd-boot_%.bbappend b/common/recipes-bsp/systemd-boot/systemd-boot_%.bbappend
> index 98eaf45..05bc490 100644
> --- a/common/recipes-bsp/systemd-boot/systemd-boot_%.bbappend
> +++ b/common/recipes-bsp/systemd-boot/systemd-boot_%.bbappend
> @@ -21,6 +21,7 @@ SRC_URI_append_intel-x86-common = " \
>               file://0004-sd-boot-Support-global-kernel-command-line-fragment-in-EFI-stub.patch \
>               file://0001-efi-boot.c-workaround-for-Joule-BIOS-hang.patch \
>               file://0001-sd-boot-stub-check-LoadOptions-contains-data.patch \
> +            file://0001-boot-efi-stub-allow-smarter-command-line-modificatio.patch \
>               "
>   
>   PACKAGE_ARCH_intel-x86-common = "${INTEL_COMMON_PACKAGE_ARCH}"



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