mtd: fix reading of image magic bytes in smaller chunks

[openwrt.git] / package / system / mtd / src / mtd.c

diff --git a/package/system/mtd/src/mtd.c b/package/system/mtd/src/mtd.c
index eda001e..dae0514 100644 (file)
--- a/package/system/mtd/src/mtd.c
+++ b/package/system/mtd/src/mtd.c
@@ -179,14 +179,21 @@ image_check(int imagefd, const char *mtd)
 {
        uint32_t magic;
        int ret = 1;
+       int bufread;
+
+       while (buflen < sizeof(magic)) {
+               bufread = read(imagefd, buf + buflen, sizeof(magic) - buflen);
+               if (bufread < 1)
+                       break;
+
+               buflen += bufread;
+       }
 
        if (buflen < sizeof(magic)) {
-               buflen += read(imagefd, buf + buflen, sizeof(magic) - buflen);
-               if (buflen < sizeof(magic)) {
-                       fprintf(stdout, "Could not get image magic\n");
-                       return 0;
-               }
+               fprintf(stdout, "Could not get image magic\n");
+               return 0;
        }
+
        magic = ((uint32_t *)buf)[0];
 
        if (be32_to_cpu(magic) == TRX_MAGIC)