From 86cf5bd1e0633f16c722500bd9717d999a7e2473 Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Thu, 28 Feb 2013 10:42:09 +0100 Subject: flash_otp_write: fix writing to NAND in presence of partial reads MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When doing something like: { printf "\xff"; printf "\xfe"; } | flash_otp_write -u /dev/mtd0 0 flash_otp_write might see only a single byte when reading from stdin for the first tim. In this case (and without this patch) it pads to $writesize with '\xff's and writes that out. In the next iteration it reads the 2nd byte, pads and writes again. So the 2nd byte is written to offset $writesize instead of 1. Signed-off-by: Uwe Kleine-König Signed-off-by: Artem Bityutskiy --- flash_otp_write.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) diff --git a/flash_otp_write.c b/flash_otp_write.c index 56769ec..3515eee 100644 --- a/flash_otp_write.c +++ b/flash_otp_write.c @@ -16,6 +16,23 @@ #include #include +ssize_t xread(int fd, void *buf, size_t count) +{ + ssize_t ret, done = 0; + +retry: + ret = read(fd, buf + done, count - done); + if (ret < 0) + return ret; + + done += ret; + + if (ret == 0 /* EOF */ || done == count) + return done; + else + goto retry; +} + int main(int argc,char *argv[]) { int fd, val, ret, size, wrote, len; @@ -67,7 +84,7 @@ int main(int argc,char *argv[]) len = 256; wrote = 0; - while ((size = read(0, buf, len))) { + while ((size = xread(0, buf, len))) { if (size < 0) { perror("read()"); return errno; -- cgit v1.2.3