From 4a4c324cd22e590990e323ed0ece974c7fa00d22 Mon Sep 17 00:00:00 2001 From: John Crispin Date: Thu, 3 Mar 2016 20:24:38 +0000 Subject: [PATCH] mtd: fix reading of image magic bytes in smaller chunks The image_check currently fails when it cannot read all magic bytes in a single chunk. But this can happen when the data are read from a pipe. This currently breaks the openmesh.sh upgrade script with musl because it uses dd with a blocksize of 1 to copy the image file to the mtd process. The read can simply be repeated until enough bytes are read for the magic byte check. It only stops when either an error was returned or 0 bytes were read. Signed-off-by: Sven Eckelmann SVN-Revision: 48891 --- package/system/mtd/src/mtd.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/package/system/mtd/src/mtd.c b/package/system/mtd/src/mtd.c index eda001e1d8..dae0514a0b 100644 --- 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)