Add extract_dtb
extract_dtb is a small utility to extract DTB files from Image.gz-dtb.
It searches the FDT header magic numbers in reversed order,
and output all found DTBs.
Test: extract_dtb Image.gz-dtb dtb Image.gz
Test: extract_dtb Image.gz-dtb dtb
Change-Id: I4e03291fd8ab5cf003f4d4cb2d153fbee56bfe7d
diff --git a/tests/src/Android.mk b/tests/src/Android.mk
index 357776c..adac198 100644
--- a/tests/src/Android.mk
+++ b/tests/src/Android.mk
@@ -30,3 +30,16 @@
include $(BUILD_HOST_EXECUTABLE)
###################################################
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := extract_dtb
+LOCAL_SRC_FILES := extract_dtb.c util.c
+LOCAL_STATIC_LIBRARIES := \
+ libfdt \
+ libufdt_sysdeps
+LOCAL_REQUIRED_MODULES := dtc
+
+include $(BUILD_HOST_EXECUTABLE)
+
+###################################################
diff --git a/tests/src/extract_dtb.c b/tests/src/extract_dtb.c
new file mode 100644
index 0000000..71b763f
--- /dev/null
+++ b/tests/src/extract_dtb.c
@@ -0,0 +1,145 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "libfdt.h"
+#include "libufdt_sysdeps.h"
+
+#include "util.h"
+
+
+int find_dtb_header_pos(const char *buf, size_t buf_size) {
+ if (buf == NULL || buf_size == 0) {
+ return -1;
+ }
+
+ int pos = buf_size;
+ while (1) {
+ pos--;
+ if (pos < 0) {
+ break;
+ }
+ uint32_t tag = fdt32_to_cpu(*(fdt32_t *)(buf + pos));
+ if (tag == FDT_MAGIC) {
+ // Hit!
+ break;
+ }
+ }
+
+ return pos;
+}
+
+int find_and_write_dtb(const char *filename,
+ const char *buf, size_t buf_size) {
+ int tag_pos = find_dtb_header_pos(buf, buf_size);
+ if (tag_pos < 0) {
+ goto end;
+ }
+
+ // Check FDT header
+ const char *fdt_ptr = buf + tag_pos;
+ if (fdt_check_header(fdt_ptr) != 0) {
+ fprintf(stderr, "Bad DTB header.\n");
+ goto end;
+ }
+
+ // Check FDT size and actual size
+ size_t fdt_size = fdt_totalsize(fdt_ptr);
+ size_t fdt_actual_size = buf_size - tag_pos;
+ int fdt_size_diff = (int)fdt_actual_size - (int)fdt_size;
+ if (fdt_size_diff) {
+ fprintf(stderr, "Wrong size: actual size = %d FDT size = %d(%d)\n",
+ fdt_actual_size, fdt_size, fdt_size_diff);
+ }
+
+ // Print the DT basic information
+ int root_node_off = fdt_path_offset(fdt_ptr, "/");
+ if (root_node_off < 0) {
+ fprintf(stderr, "Can not get the root node.\n");
+ goto end;
+ }
+ printf("Output %s\n", filename);
+ const char *model =
+ (const char *)fdt_getprop(fdt_ptr, root_node_off, "model", NULL);
+ printf(" model=%s\n", model ? model : "(unknown)");
+ const char *compatible =
+ (const char *)fdt_getprop(fdt_ptr, root_node_off, "compatible", NULL);
+ printf(" compatible=%s\n", compatible ? compatible : "(unknown)");
+
+ // Output DTB file
+ if (write_fdt_to_file(filename, fdt_ptr) != 0) {
+ fprintf(stderr, "Write file error: %s\n", filename);
+ goto end;
+ }
+
+end:
+ return tag_pos;
+}
+
+int extract_dtbs(const char *in_filename,
+ const char *out_dtb_filename,
+ const char *out_image_filename) {
+ int ret = 1;
+ char *buf = NULL;
+
+ size_t buf_size;
+ buf = load_file(in_filename, &buf_size);
+ if (!buf) {
+ fprintf(stderr, "Can not load file: %s\n", in_filename);
+ goto end;
+ }
+
+ char filename[128];
+ int index = 0;
+ while (buf_size > 0) {
+ int tag_pos;
+ if (index > 0) {
+ snprintf(filename, sizeof(filename), "%s.%d", out_dtb_filename, index);
+ tag_pos = find_and_write_dtb(filename, buf, buf_size);
+ } else {
+ tag_pos = find_and_write_dtb(out_dtb_filename, buf, buf_size);
+ }
+ if (tag_pos < 0) {
+ break;
+ }
+
+ buf_size = tag_pos;
+ index++;
+ }
+
+ if (index == 0) {
+ fprintf(stderr, "Can not find any DTB.\n");
+ goto end;
+ }
+
+ // Output the rest buffer as image file
+ if (out_image_filename != NULL) {
+ printf("Output %s\n", out_image_filename);
+ if (write_buf_to_file(out_image_filename, buf, buf_size) != 0) {
+ fprintf(stderr, "Write file error: %s\n", out_image_filename);
+ goto end;
+ }
+ }
+
+ ret = 0;
+
+end:
+ if (buf) dto_free(buf);
+
+ return ret;
+}
+
+int main(int argc, char **argv) {
+ if (argc < 3) {
+ fprintf(stderr, "Usage: %s <image.gz-dtb_file> <out_dtb_name> (<out_image_name>)\n\n", argv[0]);
+ fprintf(stderr, " Note: If there are more than one DTB, it outputs DTB files named\n" \
+ " out_dtb_name, out_dtb_name.1, out_dtb_name.2, etc.\n");
+ return 1;
+ }
+
+ const char *in_file = argv[1];
+ const char *out_dtb_file = argv[2];
+ const char *out_image_file = (argc > 3) ? argv[3] : NULL;
+ int ret = extract_dtbs(in_file, out_dtb_file, out_image_file);
+
+ return ret;
+}
diff --git a/tests/src/util.c b/tests/src/util.c
index 69f5c34..0d8040d 100644
--- a/tests/src/util.c
+++ b/tests/src/util.c
@@ -1,6 +1,7 @@
#include "util.h"
#include <stdio.h>
+#include <stdlib.h>
#include "libfdt.h"
#include "libufdt_sysdeps.h"
@@ -29,7 +30,8 @@
return buf;
}
-int write_fdt_to_file(const char *filename, void *fdt) {
+int write_buf_to_file(const char *filename,
+ const void *buf, size_t buf_size) {
int ret = 0;
FILE *fout = NULL;
@@ -38,7 +40,7 @@
ret = 1;
goto end;
}
- if (fwrite(fdt, 1, fdt_totalsize(fdt), fout) < 1) {
+ if (fwrite(buf, 1, buf_size, fout) < 1) {
ret = 2;
goto end;
}
@@ -48,3 +50,7 @@
return ret;
}
+
+int write_fdt_to_file(const char *filename, const void *fdt) {
+ return write_buf_to_file(filename, fdt, fdt_totalsize(fdt));
+}
diff --git a/tests/src/util.h b/tests/src/util.h
index f77d541..9df0ae7 100644
--- a/tests/src/util.h
+++ b/tests/src/util.h
@@ -5,6 +5,7 @@
char *load_file(const char *filename, size_t *pLen);
-int write_fdt_to_file(const char *filename, void *fdt);
+int write_buf_to_file(const char *filename, const void *buf, size_t buf_size);
+int write_fdt_to_file(const char *filename, const void *fdt);
#endif
