mkbootimg: Add Loki support
* I want my target-files built images to be Loki'd if the device
needs Loki.
* With this, devices that rely on Loki can ship Lineage Recovery
officially.
* Import loki_tool from: https://github.com/Stricted/android_external_loki.
Change-Id: I45ef363e05566268c8f24f7e8939a2d785478fbe
diff --git a/loki_tool/loki_unlok.c b/loki_tool/loki_unlok.c
new file mode 100644
index 0000000..f2e685a
--- /dev/null
+++ b/loki_tool/loki_unlok.c
@@ -0,0 +1,152 @@
+/*
+ * loki_unlok
+ *
+ * A utility to revert the changes made by loki_patch.
+ *
+ * by Dan Rosenberg (@djrbliss)
+ *
+ */
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include "loki.h"
+
+static unsigned char patch[] = PATCH;
+
+/* Find the original address of the ramdisk, which
+ * was embedded in the shellcode. */
+int find_ramdisk_addr(void *img, int sz)
+{
+
+ int i, ramdisk = 0;
+
+ for (i = 0; i < sz - (sizeof(patch) - 9); i++) {
+ if (!memcmp((char *)img + i, patch, sizeof(patch)-9)) {
+ ramdisk = *(int *)(img + i + sizeof(patch) - 5);
+ break;
+ }
+ }
+
+ return ramdisk;
+}
+
+int loki_unlok(const char* in_image, const char* out_image)
+{
+ int ifd, ofd;
+ unsigned int orig_ramdisk_size, orig_kernel_size, orig_ramdisk_addr;
+ unsigned int page_kernel_size, page_ramdisk_size, page_size, page_mask, fake_size;
+ void *orig;
+ struct stat st;
+ struct boot_img_hdr *hdr;
+ struct loki_hdr *loki_hdr;
+
+ ifd = open(in_image, O_RDONLY);
+ if (ifd < 0) {
+ printf("[-] Failed to open %s for reading.\n", in_image);
+ return 1;
+ }
+
+ ofd = open(out_image, O_WRONLY|O_CREAT|O_TRUNC, 0644);
+ if (ofd < 0) {
+ printf("[-] Failed to open %s for writing.\n", out_image);
+ return 1;
+ }
+
+ /* Map the original boot/recovery image */
+ if (fstat(ifd, &st)) {
+ printf("[-] fstat() failed.\n");
+ return 1;
+ }
+
+ orig = mmap(0, (st.st_size + 0x2000 + 0xfff) & ~0xfff, PROT_READ|PROT_WRITE, MAP_PRIVATE, ifd, 0);
+ if (orig == MAP_FAILED) {
+ printf("[-] Failed to mmap input file.\n");
+ return 1;
+ }
+
+ hdr = orig;
+ loki_hdr = orig + 0x400;
+
+ if (memcmp(loki_hdr->magic, "LOKI", 4)) {
+ printf("[-] Input file is not a Loki image.\n");
+
+ /* Copy the entire file to the output transparently */
+ if (write(ofd, orig, st.st_size) != st.st_size) {
+ printf("[-] Failed to copy Loki image.\n");
+ return 1;
+ }
+
+ printf("[+] Copied Loki image to %s.\n", out_image);
+
+ return 0;
+ }
+
+ page_size = hdr->page_size;
+ page_mask = hdr->page_size - 1;
+
+ /* Infer the size of the fake block based on the newer ramdisk address */
+ if (hdr->ramdisk_addr > 0x88f00000 || hdr->ramdisk_addr < 0xfa00000)
+ fake_size = page_size;
+ else
+ fake_size = 0x200;
+
+ orig_ramdisk_addr = find_ramdisk_addr(orig, st.st_size);
+ if (orig_ramdisk_addr == 0) {
+ printf("[-] Failed to find original ramdisk address.\n");
+ return 1;
+ }
+
+ /* Restore the original header values */
+ hdr->ramdisk_addr = orig_ramdisk_addr;
+ hdr->kernel_size = orig_kernel_size = loki_hdr->orig_kernel_size;
+ hdr->ramdisk_size = orig_ramdisk_size = loki_hdr->orig_ramdisk_size;
+
+ /* Erase the loki header */
+ memset(loki_hdr, 0, sizeof(*loki_hdr));
+
+ /* Write the image header */
+ if (write(ofd, orig, page_size) != page_size) {
+ printf("[-] Failed to write header to output file.\n");
+ return 1;
+ }
+
+ page_kernel_size = (orig_kernel_size + page_mask) & ~page_mask;
+
+ /* Write the kernel */
+ if (write(ofd, orig + page_size, page_kernel_size) != page_kernel_size) {
+ printf("[-] Failed to write kernel to output file.\n");
+ return 1;
+ }
+
+ page_ramdisk_size = (orig_ramdisk_size + page_mask) & ~page_mask;
+
+ /* Write the ramdisk */
+ if (write(ofd, orig + page_size + page_kernel_size, page_ramdisk_size) != page_ramdisk_size) {
+ printf("[-] Failed to write ramdisk to output file.\n");
+ return 1;
+ }
+
+ /* Write the device tree if needed */
+ if (hdr->dt_size) {
+
+ printf("[+] Writing device tree.\n");
+
+ /* Skip an additional fake_size (page_size of 0x200) bytes */
+ if (write(ofd, orig + page_size + page_kernel_size + page_ramdisk_size + fake_size, hdr->dt_size) != hdr->dt_size) {
+ printf("[-] Failed to write device tree to output file.\n");
+ return 1;
+ }
+ }
+
+ close(ifd);
+ close(ofd);
+
+ printf("[+] Output file written to %s\n", out_image);
+
+ return 0;
+}