From: john at keeping.me.uk (John Keeping)
Subject: [PATCH 2/2] gcc8.1: fix strcat warning
Date: Sat, 16 Jun 2018 14:11:50 +0100 [thread overview]
Message-ID: <20180616131150.GP1922@john.keeping.me.uk> (raw)
In-Reply-To: <152884644738.29435.16487549202475422342.stgit@mail.warmcat.com>
On Wed, Jun 13, 2018 at 07:34:07AM +0800, Andy Green wrote:
> ../ui-ssdiff.c: In function ?replace_tabs?:
> ../ui-ssdiff.c:142:4: warning: ?strncat? output truncated copying between 1 and 8 bytes from a string of length 8 [-Wstringop-truncation]
> strncat(result, spaces, 8 - (strlen(result) % 8));
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Actually the strncat that was there before intends that its
> stock of spaces gets truncated, and it's not a problem.
>
> However gcc8.1 is also right, normally truncation is undesirable.
>
> Make the code do the padding explicitly.
>
> Signed-off-by: Andy Green <andy at warmcat.com>
Reviewed-by: John Keeping <john at keeping.me.uk>
> ---
> ui-ssdiff.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/ui-ssdiff.c b/ui-ssdiff.c
> index 7f261ed..e520b95 100644
> --- a/ui-ssdiff.c
> +++ b/ui-ssdiff.c
> @@ -118,7 +118,6 @@ static char *replace_tabs(char *line)
> int n_tabs = 0;
> int i;
> char *result;
> - char *spaces = " ";
>
> if (linelen == 0) {
> result = xmalloc(1);
> @@ -138,8 +137,17 @@ static char *replace_tabs(char *line)
> strcat(result, prev_buf);
> break;
> } else {
> + char *p;
> + int n;
> +
> strncat(result, prev_buf, cur_buf - prev_buf);
> - strncat(result, spaces, 8 - (strlen(result) % 8));
> +
> + n = strlen(result);
> + p = result + n;
> + n = 8 - (n % 8);
> + while (n--)
> + *p++ = ' ';
> + *p = '\0';
> }
> prev_buf = cur_buf + 1;
> }
>
next prev parent reply other threads:[~2018-06-16 13:11 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-12 23:33 [PATCH 1/2] gcc8.1: fix strncpy bounds warnings andy
2018-06-12 23:34 ` [PATCH 2/2] gcc8.1: fix strcat warning andy
2018-06-16 13:11 ` john [this message]
2018-06-16 21:52 ` list
2018-06-17 2:28 ` andy
2018-06-16 13:04 ` [PATCH 1/2] gcc8.1: fix strncpy bounds warnings john
2018-06-16 13:07 ` [PATCH 1/2] shared: allocate return value from expand_macros() john
2018-06-16 13:07 ` [PATCH 2/2] shared: use strbuf for expanding macros john
2018-06-16 13:12 ` [PATCH 1/2] gcc8.1: fix strncpy bounds warnings andy
2018-06-16 14:14 ` john
2018-06-26 11:36 ` [PATCH v2 0/2] " andy
2018-06-26 11:36 ` [PATCH v2 1/2] " andy
2018-06-26 11:36 ` [PATCH v2 2/2] cgit_repobasename: convert to allocated result andy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180616131150.GP1922@john.keeping.me.uk \
--to=cgit@lists.zx2c4.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).