futility: updater: Detect the model via FRID for non-host programmers

When updating with --archive and a non-host programmer (and thus no
reliable crosid to discover the appropriate firmware manifest key), and
no explicit --model parameter is passed, try to detect the model by
matching the FRID of the current firmware with one of the host firmware
images in the archive.

Add a --detect-model-only flag to perform the same matching, but report
the detected model name and exit. This can be used in combination with
the manifest to automatically select an appropriate EC image to pass to
flash_ec.

BUG=b:253966060
TEST=futility update -a firmware.tar.bz2 --servo
BRANCH=None

Signed-off-by: Sam McNally <sammc@chromium.org>
Change-Id: I25fa0f109d0d8052179b220251d4720438b93bc4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/3965584
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/futility/updater_manifest.c b/futility/updater_manifest.c
index 339bfd8a..ca338c40 100644
--- a/futility/updater_manifest.c
+++ b/futility/updater_manifest.c
@@ -706,6 +706,58 @@ const struct model_config *manifest_find_model(const struct manifest *manifest,
 	return model;
 }
 
+const struct model_config *
+manifest_detect_model_from_frid(struct updater_config *cfg,
+				struct manifest *manifest)
+{
+	const struct model_config *result = NULL;
+	struct firmware_image current_ro_frid = {0};
+	current_ro_frid.programmer = cfg->image_current.programmer;
+	int error = flashrom_read_region(&current_ro_frid, FMAP_RO_FRID,
+					 cfg->verbosity + 1);
+	const char *from_dot;
+	int len;
+
+	if (error)
+		return NULL;
+
+	current_ro_frid.data[current_ro_frid.size - 1] = '\0';
+	from_dot = strchr((const char *)current_ro_frid.data, '.');
+	if (!from_dot) {
+		VB2_DEBUG("Missing dot (%s)\n",
+			  (const char *)current_ro_frid.data);
+		goto cleanup;
+	}
+	len = from_dot - (const char *)current_ro_frid.data + 1;
+
+	for (int i = 0; i < manifest->num && !result; ++i) {
+		struct model_config *m = &manifest->models[i];
+		struct firmware_image image = {0};
+
+		if (load_firmware_image(&image, m->image, manifest->archive))
+			return NULL;
+
+		VB2_DEBUG("Comparing '%*.*s' with '%*.*s'\n", len, len,
+			  (const char *)current_ro_frid.data, len, len,
+			  image.ro_version);
+		if (strncasecmp((const char *)current_ro_frid.data,
+				image.ro_version, len) == 0) {
+			result = m;
+		}
+		free_firmware_image(&image);
+	}
+	if (result) {
+		INFO("Detected model: '%s'\n", result->name);
+	} else {
+		ERROR("Unsupported FRID: '%*.*s'.\n", len - 1, len - 1,
+		      (const char *)current_ro_frid.data);
+	}
+cleanup:
+	free_firmware_image(&current_ro_frid);
+
+	return result;
+}
+
 /*
  * Determines the signature ID to use for custom label.
  * Returns the signature ID for looking up rootkey and vblock files.