[PATCH 1/2 v3] smbios: Simplify reporting of unknown values
Ilias Apalodimas
ilias.apalodimas at linaro.org
Wed Dec 13 23:37:44 CET 2023
On Thu, 14 Dec 2023 at 00:22, Simon Glass <sjg at chromium.org> wrote:
>
> Hi Ilias,
>
> On Wed, 13 Dec 2023 at 14:37, Ilias Apalodimas
> <ilias.apalodimas at linaro.org> wrote:
> >
> > Hi Simon,
> >
> > On Wed, 13 Dec 2023 at 21:52, Simon Glass <sjg at chromium.org> wrote:
> > >
> > > Hi Ilias,
> > >
> > > On Thu, 7 Dec 2023 at 02:19, Ilias Apalodimas
> > > <ilias.apalodimas at linaro.org> wrote:
> > > >
> > > > If a value is not valid during the DT or SYSINFO parsing, we explicitly
> > > > set that to "Unknown Product" and "Unknown" for the product and
> > > > manufacturer respectively. It's cleaner if we move the checks insisde
> > > > smbios_add_prop_si() and provide an alternative string in case the
> > > > primary is NULL or empty
> > > >
> > > > pre-patch dmidecode
> > > > <snip>
> > > > Handle 0x0001, DMI type 1, 27 bytes
> > > > System Information
> > > > Manufacturer: Unknown
> > > > Product Name: Unknown Product
> > > > Version: Not Specified
> > > > Serial Number: Not Specified
> > > > UUID: Not Settable
> > > > Wake-up Type: Reserved
> > > > SKU Number: Not Specified
> > > > Family: Not Specified
> > > >
> > > > [...]
> > > >
> > > > post-patch dmidecode:
> > > >
> > > > Handle 0x0001, DMI type 1, 27 bytes
> > > > System Information
> > > > Manufacturer: Unknown
> > > > Product Name: Unknown
> > > > Version: Unknown
> > > > Serial Number: Unknown
> > > > UUID: Not Settable
> > > > Wake-up Type: Reserved
> > > > SKU Number: Unknown
> > > > Family: Unknown
> > > > [...]
> > > >
> > > > While at it make smbios_add_prop_si() add a string directly if the prop
> > > > node is NULL and replace smbios_add_string() calls with
> > > > smbios_add_prop_si(ctx, NULL, ....)
> > > >
> > > > Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> > > > ---
> > > > Changes since v2:
> > > > - refactor even more code and remove the smbios_add_string calls from the
> > > > main code. Instead use smbios_add_prop() foir everything and add a
> > > > default value, in case the parsed one is NULL or emtpy
> > > > Changes since v1:
> > > > - None
> > > >
> > > > lib/smbios.c | 73 +++++++++++++++++++++++++---------------------------
> > > > 1 file changed, 35 insertions(+), 38 deletions(-)
> > > >
> > >
> > > I actually think we should just stop here and first write a test for
> > > what we already have. I can take a crack at it if you like?
> >
> > I don't mind. As I said in a previous email I'd rather do it after
> > the refactoring you had in mind. But I don't see why that should stop
> > the current patch from going forward.
>
> OK, well if this series could be simplified, I don't mind either. But
> at present it is complicated and I think it really needs a test.
>
> >
> > >
> > > > diff --git a/lib/smbios.c b/lib/smbios.c
> > > > index d7f4999e8b2a..444aa245a273 100644
> > > > --- a/lib/smbios.c
> > > > +++ b/lib/smbios.c
> > > > @@ -102,9 +102,6 @@ static int smbios_add_string(struct smbios_ctx *ctx, const char *str)
> > > > int i = 1;
> > > > char *p = ctx->eos;
> > > >
> > > > - if (!*str)
> > > > - str = "Unknown";
> > > > -
> > > > for (;;) {
> > > > if (!*p) {
> > > > ctx->last_str = p;
> > > > @@ -134,11 +131,18 @@ static int smbios_add_string(struct smbios_ctx *ctx, const char *str)
> > > > *
> > > > * @ctx: context for writing the tables
> > > > * @prop: property to write
> > >
> > > which can now be NULL?
> >
> > No, it can't because smbios_add_string can't do that. See commit 00a871d34e2f0a.
> > But instead of checking it here, I moved the code around and
> > smbios_add_string is only called from smbios_add_prop_si instead of
> > calling it on each failure of smbios_add_prop_si(). In that function,
> > we make sure the value isn't NULL, apart from the ->get_str sysinfo
> > calls -- none of these currently returns null though. I can move the
> > checking back to where it was if to shield us again dump 'get_str'
> > implementations, or in the future fix smbios_add_string properly, but
> > that's not the point of this patch.
>
> My point was that you have code to check for !prop and do something:
>
> if (!prop)
> return smbios_add_string(ctx, dval);
>
> Before, we needed prop (at least if OF_CONTROL), but now prop can be
> NULL, so you should update the comment to mention that and explain
> what it means.
Sure
>
> >
> > >
> > > > + * @dval: Default value to use if the string is not found or is empty
> > > > * Return: 0 if not found, else SMBIOS string number (1 or more)
> > > > */
> > > > static int smbios_add_prop_si(struct smbios_ctx *ctx, const char *prop,
> > > > - int sysinfo_id)
> > > > + int sysinfo_id, const char *dval)
> > > > {
> > > > + if (!dval || !*dval)
> > > > + dval = "Unknown";
> > >
> > > You shouldn't need this, right? It is already the default value.
> >
> > Unless someone misuses smbios_add_prop_si() with both the prop and
> > dval being NULL. Also see above.
>
> Don't allow that, then?
But I am not allowing it. Instead of returning an error though we
implicitly set it to unknown, which is exactly what we used to do.
> It seems strange to have a default value for the default value.
That's how smbios_add_string works now. Since Heinrich found that
problem we should eventually fix smbios_add_string() to return and
error on NULL ptrs and empty strings . But the point of this patchset
is to clean up the random ad-hoc calls of it, not fix it (yet)
>
> >
> > >
> > > > +
> > > > + if (!prop)
> > > > + return smbios_add_string(ctx, dval);
> > > > +
> > > > if (sysinfo_id && ctx->dev) {
> > > > char val[SMBIOS_STR_MAX];
> > > > int ret;
> > > > @@ -151,8 +155,8 @@ static int smbios_add_prop_si(struct smbios_ctx *ctx, const char *prop,
> > > > const char *str;
> > > >
> > > > str = ofnode_read_string(ctx->node, prop);
> > > > - if (str)
> > > > - return smbios_add_string(ctx, str);
> > > > +
> > > > + return smbios_add_string(ctx, str ? str : dval);
> > > > }
> > > >
> > > > return 0;
> > > > @@ -161,12 +165,15 @@ static int smbios_add_prop_si(struct smbios_ctx *ctx, const char *prop,
> > > > /**
> > > > * smbios_add_prop() - Add a property from the devicetree
> > > > *
> > > > - * @prop: property to write
> > > > + * @prop: property to write. The default string will be written if
> > > > + * prop is NULL
> > > > + * @dval: Default value to use if the string is not found or is empty
> > > > * Return: 0 if not found, else SMBIOS string number (1 or more)
> > > > */
> > > > -static int smbios_add_prop(struct smbios_ctx *ctx, const char *prop)
> > > > +static int smbios_add_prop(struct smbios_ctx *ctx, const char *prop,
> > > > + const char *dval)
> > > > {
> > > > - return smbios_add_prop_si(ctx, prop, SYSINFO_ID_NONE);
> > > > + return smbios_add_prop_si(ctx, prop, SYSINFO_ID_NONE, dval);
> > > > }
> > > >
> > > > static void smbios_set_eos(struct smbios_ctx *ctx, char *eos)
> > > > @@ -228,11 +235,9 @@ static int smbios_write_type0(ulong *current, int handle,
> > > > memset(t, 0, sizeof(struct smbios_type0));
> > > > fill_smbios_header(t, SMBIOS_BIOS_INFORMATION, len, handle);
> > > > smbios_set_eos(ctx, t->eos);
> > > > - t->vendor = smbios_add_string(ctx, "U-Boot");
> > > > + t->vendor = smbios_add_prop(ctx, NULL, "U-Boot");
> > >
> > > What is this doing exactly? I don't really understand this change.
> >
> > Re-read the patch description please, it's explained in the last paragraph.
> >
> > >
> > > >
> >
> > [...]
> >
> > > > 2.40.1
> > > >
> > >
> > > From my understanding, the only thing your fallback adds is the
> > > manufacturer ('vendor' from DT compatible = "vendor,board"), and the
> > > product (from DT model = "..."). This is an awful lot of code to make
> > > that change and it seems very, confusing to me.
> >
> > Can we please comment on the current patchset? Future history and
> > digging becomes a nightmare otherwise.
> >
> > >
> > > Instead, can you do something like:
> > >
> > > if (!IS_ENABLED(CONFIG_SYSINFO)) {
> >
> > That beats the purpose of the series though, we want this as a
> > *fallback* not disabled in the defconfig.
> >
> > > const char *compat = ofnode_read_string(ofnode_root(), "compatible");
> > > const char *model = ofnode_read_string(ofnode_root(), "model");
> > > const *p = strchr(compat, ',');
> >
> > No. This is just a quick and dirty patch that allows you to split on
> > the first comma. On top of that it won't work for cases like 'model'
> > which, most of the times, only has a single value (which is again
> > explained in the patch description) and you have to add a bunch of ifs
> > on the code above. You could only parse compatible only, but model
> > tends to be way more accurate than the one added in the compatible
> > node. The first is a full description of the device while the latter
> > is just a trigger for driver probing etc.
> >
> > random example
> > model = "Socionext Developer Box";
> > compatible = "socionext,developer-box", "socionext,synquacer";
>
> But your code does the same as my fragment above, doesn't it? Only the
> compatible string is split, and only the first part (before the ',')
> is used.
>
> For the model, the whole string is used,
> so having a function to split
> the string, which doesn't have a separator in it, seems unnecessary.
No, it's not. the spec says model = <manufacturer, model>. Some of the
existing DTs follow that pattern. In that case, you need to split
those as well and that code would start to look really ugly and non
extendable. NXP and Qualcomm boards are just some examples
>
> I am not talking about the end result, just trying to make the code
> easier to understand. It is very complex right now.
The function has a pretty clear comment on what it tries to do.
Also if we do what you suggest, adding chassis-id would mean that we
need another round of strchrs and ifs and who knows what else. With
the current patch, you just need to add an entry to the array
something along the lines of
{ .sysinfo_str = "chassis", .dt_str = "chassis-type", 1}
Thanks
/Ilias
>
>
> >
> > > char vendor[32];
> > >
> > > *vendor = '\0';
> > > if (p) {
> > > int len = p - compat + 1;
> > >
> > > strlcpy(vendor, compat, len);
> > > }
> > >
> > > // add these two strings to the ctx struct so that
> > > smbios_write_type1() can pass them as defaults
> > > }
> > >
> > > You still need to make the 'default' change, but much of the other
> > > code could go away?
>
> Regards,
> Simon
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