From: "Power, Ciara" <ciara.power@intel.com>
To: "Morten Brørup" <mb@smartsharesystems.com>,
fengchengwen <fengchengwen@huawei.com>,
"Stephen Hemminger" <stephen@networkplumber.org>,
"Richardson, Bruce" <bruce.richardson@intel.com>
Cc: "thomas@monjalon.net" <thomas@monjalon.net>,
"ferruh.yigit@xilinx.com" <ferruh.yigit@xilinx.com>,
"Laatz, Kevin" <kevin.laatz@intel.com>,
"andrew.rybchenko@oktetlabs.ru" <andrew.rybchenko@oktetlabs.ru>,
"jerinj@marvell.com" <jerinj@marvell.com>,
"sachin.saxena@oss.nxp.com" <sachin.saxena@oss.nxp.com>,
"hemant.agrawal@nxp.com" <hemant.agrawal@nxp.com>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: RE: [PATCH v2 1/5] telemetry: escape special char when tel string
Date: Wed, 22 Jun 2022 07:57:43 +0000 [thread overview]
Message-ID: <MN2PR11MB3821024B050911BB5F524CFEE6B29@MN2PR11MB3821.namprd11.prod.outlook.com> (raw)
In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC35D8713F@smartserver.smartshare.dk>
Hi folks,
> -----Original Message-----
> From: Morten Brørup <mb@smartsharesystems.com>
> Sent: Saturday 18 June 2022 10:59
> To: fengchengwen <fengchengwen@huawei.com>; Stephen Hemminger
> <stephen@networkplumber.org>; Richardson, Bruce
> <bruce.richardson@intel.com>
> Cc: thomas@monjalon.net; ferruh.yigit@xilinx.com; Laatz, Kevin
> <kevin.laatz@intel.com>; andrew.rybchenko@oktetlabs.ru;
> jerinj@marvell.com; sachin.saxena@oss.nxp.com;
> hemant.agrawal@nxp.com; dev@dpdk.org; Power, Ciara
> <ciara.power@intel.com>
> Subject: RE: [PATCH v2 1/5] telemetry: escape special char when tel string
>
> +CC: Ciara Power, Telemetry library maintainer
>
> > From: fengchengwen [mailto:fengchengwen@huawei.com]
> > Sent: Saturday, 18 June 2022 05.52
> >
> > On 2022/6/18 1:05, Stephen Hemminger wrote:
> > > On Fri, 17 Jun 2022 12:25:04 +0100
> > > Bruce Richardson <bruce.richardson@intel.com> wrote:
> > >
> > >> On Fri, Jun 17, 2022 at 01:16:08PM +0200, Morten Brørup wrote:
> > >>>> From: Chengwen Feng [mailto:fengchengwen@huawei.com]
> > >>>> Sent: Friday, 17 June 2022 11.46
> > >>>>
> > >>>> This patch supports escape special characters (including:
> > \",\\,/,\b,
> > >>>> /f,/n,/r,/t) when telemetry string.
> > >>>> This patch is used to support telemetry xxx-dump commands which
> > the
> > >>>> string may include special characters.
> > >>>>
> > >>>> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
> > >>>> ---
> > >>>> lib/telemetry/telemetry.c | 96
> > +++++++++++++++++++++++++++++++++++++--
> > >>>> 1 file changed, 93 insertions(+), 3 deletions(-)
> > >>>>
> > >>>> diff --git a/lib/telemetry/telemetry.c
> > >>>> b/lib/telemetry/telemetry.c index c6fd03a5ab..0f762f633e 100644
> > >>>> --- a/lib/telemetry/telemetry.c
> > >>>> +++ b/lib/telemetry/telemetry.c
> > >>>> @@ -215,6 +215,94 @@ container_to_json(const struct rte_tel_data
> > *d,
> > >>>> char *out_buf, size_t buf_len)
> > >>>> return used;
> > >>>> }
> > >>>>
> > >>>> +static bool
> > >>>> +json_is_special_char(char ch)
> > >>>> +{
> > >>>> + static unsigned char is_spec[256] = { 0 };
> > >>>> + static bool init_once;
> > >>>> +
> > >>>> + if (!init_once) {
> > >>>> + is_spec['\"'] = 1;
> > >>>> + is_spec['\\'] = 1;
> > >>>> + is_spec['/'] = 1;
> > >>>> + is_spec['\b'] = 1;
> > >>>> + is_spec['\f'] = 1;
> > >>>> + is_spec['\n'] = 1;
> > >>>> + is_spec['\r'] = 1;
> > >>>> + is_spec['\t'] = 1;
> > >>>> + init_once = true;
> > >>>> + }
> > >>>> +
> > >>>> + return (bool)is_spec[(unsigned char)ch]; }
> > >>
> > >> According to the json spec at [1], the characters that need to be
> > escaped
> > >> are:
> > >> a) any characters <0x20
> > >> b) inverted commas/quote character \"
> > >> c) the "reverse solidus character", better known to you and I as
> > >> the back-slash.
> > >>
> > >> Therefore, I think this table generation could be simplified, but
> > also
> > >> expanded using this. For completeness we should also see about
> > handling all
> > >> control characters if they are encountered.
> > >>
> > >> [1] https://www.rfc-editor.org/rfc/rfc8259.txt
> > >>
> > >> /Bruce
> > >
> > > Since it is trivial could be initializer?
> > >
> > > static const uint8_t is_spec[256] = {
> > > [0 ... 0x20] = 1,
> > > ['\"' ] = 1,
> > > ['\\' ] = 1,
> > > ['/'] = 1,
> > >
> > > etc
> > >
> > > Or we could change the telemetry API to disallow control characters?
> >
> > I was thinking about converting 0~0x20, but I don't think there's a
> > scenario.
> >
> > I prefer change the telemetry API to disallow control characters, and
> > this may not be a violation of the ABI, if yes, the dpdk-telemetry.py
> > will returns an error.
>
> I agree with Chengwen Feng. The telemetry data type is STRING, not BLOB.
>
> So we need to define exactly what the STRING type contains.
>
> I hope we can all agree that control characters should be disallowed.
>
> The more complicated question is: Do we want to use the ASCII character set
> only, or do we want to use UTF-8 encoded Unicode?
>
> Personally, think UTF-8 encoded Unicode is more future proof, and would
> vote for that.
>
> But I wouldn't reject limiting it to ASCII, and perhaps in the future introduce
> another data type for UTF-8 strings.
>
> UTF-8 is the modern choice, but it is incompatible with old stuff, e.g. many
> SNMP MIBs.
>
[CP]
Just from looking at the spec [1] , I would say UTF-8, as it seems to suggest its use for JSON (section 8.1).
[1] https://www.rfc-editor.org/rfc/rfc8259.txt
> >
> > So I think we could add declaring and checking functions to make sure
> > telemetry string do not allow control characters.
[CP]
I am not sure why we don't want these at all - I thought we do want some of them, like tab (\u0009) for example.
<snip>
In general, I think Bruce's suggestion of using a customised printf function instead of snprintf would be a good way forward, to scan the chars as they are being copied in.
Thanks,
Ciara
next prev parent reply other threads:[~2022-06-22 7:57 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-15 7:39 [PATCH 0/5] support telemetry dump dev Chengwen Feng
2022-06-15 7:39 ` [PATCH 1/5] usertools: use non-strict when json-loads in telemetry Chengwen Feng
2022-06-15 13:54 ` Morten Brørup
2022-06-15 16:54 ` Bruce Richardson
2022-06-15 18:01 ` Morten Brørup
2022-06-15 20:09 ` Morten Brørup
2022-06-15 7:39 ` [PATCH 2/5] dmadev: support telemetry dump dmadev Chengwen Feng
2022-06-15 7:39 ` [PATCH 3/5] eventdev: support telemetry dump eventdev Chengwen Feng
2022-06-15 7:39 ` [PATCH 4/5] rawdev: support telemetry dump rawdev Chengwen Feng
2022-06-15 7:39 ` [PATCH 5/5] ethdev: support telemetry private dump Chengwen Feng
2022-06-15 20:15 ` [PATCH 0/5] support telemetry dump dev Morten Brørup
2022-06-16 8:19 ` Bruce Richardson
2022-06-16 9:00 ` Morten Brørup
2022-06-17 9:46 ` [PATCH v2 0/5] support telemetry dump Chengwen Feng
2022-06-17 9:46 ` [PATCH v2 1/5] telemetry: escape special char when tel string Chengwen Feng
2022-06-17 11:16 ` Morten Brørup
2022-06-17 11:25 ` Bruce Richardson
2022-06-17 17:05 ` Stephen Hemminger
2022-06-18 3:52 ` fengchengwen
2022-06-18 9:59 ` Morten Brørup
2022-06-22 7:57 ` Power, Ciara [this message]
2022-06-22 9:19 ` Bruce Richardson
2022-06-23 16:45 ` Bruce Richardson
2022-06-17 11:27 ` Bruce Richardson
2022-06-17 9:46 ` [PATCH v2 2/5] dmadev: support telemetry dump dmadev Chengwen Feng
2022-06-17 9:46 ` [PATCH v2 3/5] eventdev: support telemetry dump eventdev Chengwen Feng
2022-06-17 9:46 ` [PATCH v2 4/5] rawdev: support telemetry dump rawdev Chengwen Feng
2022-06-17 9:46 ` [PATCH v2 5/5] ethdev: support telemetry private dump Chengwen Feng
2022-09-13 2:44 ` [PATCH v3 0/4] support telemetry dump dev Chengwen Feng
2022-09-13 2:44 ` [PATCH v3 1/4] dmadev: support telemetry dump dmadev Chengwen Feng
2022-09-13 2:44 ` [PATCH v3 2/4] eventdev: support telemetry dump eventdev Chengwen Feng
2022-09-13 2:44 ` [PATCH v3 3/4] rawdev: support telemetry dump rawdev Chengwen Feng
2022-09-13 2:44 ` [PATCH v3 4/4] ethdev: support telemetry private dump Chengwen Feng
2022-09-13 7:13 ` [PATCH v4 0/4] support telemetry dump dev Chengwen Feng
2022-09-13 7:13 ` [PATCH v4 1/4] dmadev: support telemetry dump dmadev Chengwen Feng
2022-09-13 7:13 ` [PATCH v4 2/4] eventdev: support telemetry dump eventdev Chengwen Feng
2022-09-13 7:13 ` [PATCH v4 3/4] rawdev: support telemetry dump rawdev Chengwen Feng
2022-09-13 7:13 ` [PATCH v4 4/4] ethdev: support telemetry private dump Chengwen Feng
2022-10-03 7:28 ` [PATCH v4 0/4] support telemetry dump dev David Marchand
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