From: Tyler Retzlaff <roretzla@linux.microsoft.com>
To: Bruce Richardson <bruce.richardson@intel.com>
Cc: dev@dpdk.org, ciara.power@intel.com
Subject: Re: [PATCH v3 2/5] telemetry: remove variable length array in printf fn
Date: Fri, 7 Apr 2023 12:25:36 -0700 [thread overview]
Message-ID: <20230407192536.GC3014@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> (raw)
In-Reply-To: <20230405160326.186921-3-bruce.richardson@intel.com>
On Wed, Apr 05, 2023 at 05:03:23PM +0100, Bruce Richardson wrote:
> The json_snprintf function, used to add json characters on to a buffer,
> leaving the buffer unmodified in case of error, used a variable length
> array to store the data temporarily while checking for overflow. VLAs
> can be unsafe, and are unsupported by some compilers, so remove use of
> the VLA.
>
> For the normal case where there is only a small amount of existing text
> in the buffer (<4 chars) to be preserved, save that off temporarily to a
> local array, and restore on error. To handle cases where there is more
> than a few characters in the buffer, we use the existing logic of doing
> the print to a temporary buffer initially and then copying. In this
> case, though we use malloc-allocated buffer rather than VLA.
>
> Within the unit tests, the "telemetry_data_autotests" test cases - which
> mimic real telemetry use - all exercise the first path. The
> telemetry_json_autotest cases work directly with generating json, and
> use uninitialized buffers so also test the second, malloc-allocated
> buffer, cases.
>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
>
> ---
Acked-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
next prev parent reply other threads:[~2023-04-07 19:25 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-10 18:18 [PATCH] telemetry: fix autotest failures on Alpine Bruce Richardson
2023-03-10 19:08 ` Stephen Hemminger
2023-03-13 9:38 ` Bruce Richardson
2023-04-05 15:44 ` [PATCH v2 0/5] telemetry: remove variable length arrays Bruce Richardson
2023-04-05 15:44 ` [PATCH v2 1/5] telemetry: fix autotest failures on Alpine Bruce Richardson
2023-04-07 19:21 ` Tyler Retzlaff
2023-04-11 8:43 ` Bruce Richardson
2023-04-05 15:44 ` [PATCH v2 2/5] telemetry: remove variable length array in printf fn Bruce Richardson
2023-04-05 15:44 ` [PATCH v2 3/5] telemetry: split out body of json string format fn Bruce Richardson
2023-04-05 15:44 ` [PATCH v2 4/5] telemetry: rename local variables Bruce Richardson
2023-04-05 15:44 ` [PATCH v2 5/5] telemetry: remove VLA in json string format function Bruce Richardson
2023-04-05 16:03 ` [PATCH v3 0/5] telemetry: remove variable length arrays Bruce Richardson
2023-04-05 16:03 ` [PATCH v3 1/5] telemetry: fix autotest failures on Alpine Bruce Richardson
2023-04-07 19:22 ` Tyler Retzlaff
2023-04-05 16:03 ` [PATCH v3 2/5] telemetry: remove variable length array in printf fn Bruce Richardson
2023-04-07 19:25 ` Tyler Retzlaff [this message]
2023-04-05 16:03 ` [PATCH v3 3/5] telemetry: split out body of json string format fn Bruce Richardson
2023-04-07 19:28 ` Tyler Retzlaff
2023-04-05 16:03 ` [PATCH v3 4/5] telemetry: rename local variables Bruce Richardson
2023-04-07 19:50 ` Tyler Retzlaff
2023-04-11 8:58 ` Bruce Richardson
2023-04-05 16:03 ` [PATCH v3 5/5] telemetry: remove VLA in json string format function Bruce Richardson
2023-04-07 19:54 ` Tyler Retzlaff
2023-05-25 7:12 ` David Marchand
2023-05-24 20:47 ` [PATCH v3 0/5] telemetry: remove variable length arrays Thomas Monjalon
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=20230407192536.GC3014@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net \
--to=roretzla@linux.microsoft.com \
--cc=bruce.richardson@intel.com \
--cc=ciara.power@intel.com \
--cc=dev@dpdk.org \
/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).