Re: [PATCH] ihex: fix unused return value compiler warning.

From: Andrew Morton
Date: Mon Jan 03 2011 - 14:52:56 EST


On Sun, 2 Jan 2011 11:27:10 -0800
Chris Ruffin <cmruffin@xxxxxxxxx> wrote:

> fixed unusued return value compiler warnings due to unchecked write() calls.
>
> Signed-off-by: Chris Ruffin <cmruffin@xxxxxxxxx>
> ---
> firmware/ihex2fw.c | 9 +++++----
> 1 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/firmware/ihex2fw.c b/firmware/ihex2fw.c
> index ba0cf0b..a079bdd 100644
> --- a/firmware/ihex2fw.c
> +++ b/firmware/ihex2fw.c
> @@ -124,8 +124,7 @@ int main(int argc, char **argv)
> if (process_ihex(data, st.st_size))
> return 1;
>
> - output_records(outfd);
> - return 0;
> + return output_records(outfd);
> }
>
> static int process_ihex(uint8_t *data, ssize_t size)
> @@ -269,11 +268,13 @@ static int output_records(int outfd)
>
> p->addr = htonl(p->addr);
> p->len = htons(p->len);
> - write(outfd, &p->addr, writelen);
> + if (write(outfd, &p->addr, writelen) != writelen)
> + return errno;
> p = p->next;
> }
> /* EOF record is zero length, since we don't bother to represent
> the type field in the binary version */
> - write(outfd, zeroes, 6);
> + if (write(outfd, zeroes, 6) != 6)
> + return errno;
> return 0;
> }

write(1) will only set errno if it returned -1. So in the case where
write() returned a positive number less than `count', output_records()
will return a garbage value of `errno'.

I guess this will suffice:

--- a/firmware/ihex2fw.c~ihex-fix-unused-return-value-compiler-warning-fix
+++ a/firmware/ihex2fw.c
@@ -269,12 +269,12 @@ static int output_records(int outfd)
p->addr = htonl(p->addr);
p->len = htons(p->len);
if (write(outfd, &p->addr, writelen) != writelen)
- return errno;
+ return 1;
p = p->next;
}
/* EOF record is zero length, since we don't bother to represent
the type field in the binary version */
if (write(outfd, zeroes, 6) != 6)
- return errno;
+ return 1;
return 0;
}
_

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