Load kernel and initrd into an existing image.

This allows us to replace both kernel and initrd from an existing image
and keep its command line, atags, and load addresses, just changing the
kernel and initrd sizes.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@cascardo.eti.br>

diff --git a/bootimg.c b/bootimg.c
index b015c10..cacd658 100644 (file)
--- a/bootimg.c
+++ b/bootimg.c
@@ -105,14 +105,20 @@ static int load(int fd, size_t *len, int pgsz, char *fname)
 int main(int argc, char **argv)
 {
        int fd;
-       uint32_t kernel, initrd, second, pgsz;
+       uint32_t *kernel, *initrd, *second, pgsz;
        char buffer[4096];
        char *p;
        int r;
        off_t offset;
+       int is_load;
        if (argc < 2)
                return 1;
-       fd = open(argv[1], O_RDONLY);
+       if (argc > 2)
+               is_load = 1;
+       if (is_load)
+               fd = open(argv[1], O_RDWR);
+       else
+               fd = open(argv[1], O_RDONLY);
        if (fd < 0) {
                return 2;
        }
@@ -123,27 +129,40 @@ int main(int argc, char **argv)
        if (strncmp(buffer, "ANDROID!", 8)) {
                return 4;
        }
-       kernel = *(uint32_t *) p;
+       kernel = (uint32_t *) p;
        p += 8;
-       initrd = *(uint32_t *) p;
+       initrd = (uint32_t *) p;
        p += 8;
-       second = *(uint32_t *) p;
+       second = (uint32_t *) p;
        p += 12;
        pgsz = *(uint32_t *) p;
        offset = pgsz;
-       if (kernel > 0) {
+       if (!is_load && *kernel > 0) {
+               lseek(fd, offset, SEEK_SET);
+               dump(fd, *kernel, pgsz, "kernel");
+       } else {
                lseek(fd, offset, SEEK_SET);
-               dump(fd, kernel, pgsz, "kernel");
+               load(fd, kernel, pgsz, "kernel");
        }
-       offset += ((kernel + pgsz - 1) / pgsz) * pgsz;
-       if (initrd > 0) {
+       offset += ((*kernel + pgsz - 1) / pgsz) * pgsz;
+       if (!is_load && *initrd > 0) {
                lseek(fd, offset, SEEK_SET);
-               dump(fd, initrd, pgsz, "initrd");
+               dump(fd, *initrd, pgsz, "initrd");
+       } else {
+               lseek(fd, offset, SEEK_SET);
+               load(fd, initrd, pgsz, "initrd");
        }
-       offset += ((initrd + pgsz - 1) / pgsz) * pgsz;
-       if (second > 0) {
+       offset += ((*initrd + pgsz - 1) / pgsz) * pgsz;
+       if (!is_load && *second > 0) {
                lseek(fd, offset, SEEK_SET);
-               dump(fd, second, pgsz, "second");
+               dump(fd, *second, pgsz, "second");
+       } else {
+               /* For now, don't care about using second. */
+               /* The header must be written back, and we may need to
+                * truncate the file. */
+               ftruncate(fd, offset);
+               lseek(fd, 0, SEEK_SET);
+               write(fd, buffer, pgsz);
        }
        close(fd);
        return 0;