[PATCH] libdvbv5: more fixes in the T2 delivery descriptor handler

[PATCH] libdvbv5: more fixes in the T2 delivery descriptor handler

[Nikolaus Schulz]

* Fix a couple of memcpy calls, and remove a bogus one
* Properly use lengths of centre_frequency loop and subcell_info loop
  (they count bytes, not entries)

Signed-off-by: Nikolaus Schulz <schulz@macnetix.de>
---
 lib/libdvbv5/descriptors/desc_t2_delivery.c |   35 ++++++++++++++-------------
 1 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/lib/libdvbv5/descriptors/desc_t2_delivery.c b/lib/libdvbv5/descriptors/desc_t2_delivery.c
index ab4361d..07a0956 100644
--- a/lib/libdvbv5/descriptors/desc_t2_delivery.c
+++ b/lib/libdvbv5/descriptors/desc_t2_delivery.c
@@ -32,6 +32,7 @@ void dvb_desc_t2_delivery_init(struct dvb_v5_fe_parms *parms,
 	struct dvb_desc_t2_delivery *d = desc;
 	unsigned char *p = (unsigned char *) buf;
 	size_t desc_len = ext->length - 1, len, len2;
+	uint8_t nmemb;
 	int i;
 
 	len = offsetof(struct dvb_desc_t2_delivery, bitfield);
@@ -42,7 +43,7 @@ void dvb_desc_t2_delivery_init(struct dvb_v5_fe_parms *parms,
 		return;
 	}
 	if (desc_len < len2) {
-		memcpy(p, buf, len);
+		memcpy(d, p, len);
 		bswap16(d->system_id);
 
 		if (desc_len != len)
@@ -50,44 +51,41 @@ void dvb_desc_t2_delivery_init(struct dvb_v5_fe_parms *parms,
 
 		return;
 	}
-	memcpy(p, buf, len2);
+	memcpy(d, p, len2);
 	p += len2;
 
-	len = desc_len - (p - buf);
-	memcpy(&d->centre_frequency, p, len);
-	p += len;
-
 	if (d->tfs_flag)
-		d->frequency_loop_length = 1;
+		d->frequency_loop_length = sizeof(*d->centre_frequency);
 	else {
 		d->frequency_loop_length = *p;
 		p++;
 	}
+	nmemb = d->frequency_loop_length / sizeof(*d->centre_frequency);
 
-	d->centre_frequency = calloc(d->frequency_loop_length,
-				     sizeof(*d->centre_frequency));
+	d->centre_frequency = calloc(nmemb, sizeof(*d->centre_frequency));
 	if (!d->centre_frequency) {
 		dvb_perror("Out of memory");
 		return;
 	}
 
-	memcpy(d->centre_frequency, p, sizeof(*d->centre_frequency) * d->frequency_loop_length);
-	p += sizeof(*d->centre_frequency) * d->frequency_loop_length;
+	memcpy(d->centre_frequency, p, d->frequency_loop_length);
+	p += d->frequency_loop_length;
 
-	for (i = 0; i < d->frequency_loop_length; i++)
+	for (i = 0; i < nmemb; i++)
 		bswap32(d->centre_frequency[i]);
 
 	d->subcel_info_loop_length = *p;
 	p++;
+	nmemb = d->subcel_info_loop_length / sizeof(*d->subcell);
 
-	d->subcell = calloc(d->subcel_info_loop_length, sizeof(*d->subcell));
+	d->subcell = calloc(nmemb, sizeof(*d->subcell));
 	if (!d->subcell) {
 		dvb_perror("Out of memory");
 		return;
 	}
-	memcpy(d->subcell, p, sizeof(*d->subcell) * d->subcel_info_loop_length);
+	memcpy(d->subcell, p, d->subcel_info_loop_length);
 
-	for (i = 0; i < d->subcel_info_loop_length; i++)
+	for (i = 0; i < nmemb; i++)
 		bswap16(d->subcell[i].transposer_frequency);
 }
 
@@ -97,6 +95,7 @@ void dvb_desc_t2_delivery_print(struct dvb_v5_fe_parms *parms,
 {
 	const struct dvb_desc_t2_delivery *d = desc;
 	int i;
+	uint8_t nmemb;
 
 	dvb_log("|       DVB-T2 delivery");
 	dvb_log("|           plp_id                    %d", d->plp_id);
@@ -113,10 +112,12 @@ void dvb_desc_t2_delivery_print(struct dvb_v5_fe_parms *parms,
 	dvb_log("|           bandwidth                 %d", d->bandwidth);
 	dvb_log("|           SISO MISO                 %d", d->SISO_MISO);
 
-	for (i = 0; i < d->frequency_loop_length; i++)
+	nmemb = d->frequency_loop_length / sizeof(*d->centre_frequency);
+	for (i = 0; i < nmemb; i++)
 		dvb_log("|           centre frequency[%d]   %d", i, d->centre_frequency[i]);
 
-	for (i = 0; i < d->subcel_info_loop_length; i++) {
+	nmemb = d->subcel_info_loop_length / sizeof(*d->subcell);
+	for (i = 0; i < nmemb; i++) {
 		dvb_log("|           cell_id_extension[%d]  %d", i, d->subcell[i].cell_id_extension);
 		dvb_log("|           transposer frequency   %d", d->subcell[i].transposer_frequency);
 	}
-- 
1.7.2.5

Re: [PATCH] libdvbv5: more fixes in the T2 delivery descriptor handler

[Mauro Carvalho Chehab]

Thanks for the patch!

Em Thu, 5 Dec 2013 16:10:03 +0100
Nikolaus Schulz <schulz@macnetix.de> escreveu:

> * Fix a couple of memcpy calls, and remove a bogus one

That changes look OK to me.

> * Properly use lengths of centre_frequency loop and subcell_info loop
>   (they count bytes, not entries)

I'm not sure about this one. On all other similar descriptors, we're storing
the number of elements at the descriptor's structure, instead of its size,
as that makes easier to handle them.

Also, having all delivery_system descriptors using the number of elements
makes easier to avoid confusion when writing the handling code.

Btw, I think that this change will likely break the code that handles this
descriptor at dvb-scan.

So, could you please redo your patch in order for it to keep storing the
number of elements at the dvb_desc_t2_delivery::frequency_loop_length
field? If you prefer, you can rename it to frequency_loop_nmemb (or a
similar naming) to make it clearer.

Regards,
Mauro

> 
> Signed-off-by: Nikolaus Schulz <schulz@macnetix.de>
> ---
>  lib/libdvbv5/descriptors/desc_t2_delivery.c |   35 ++++++++++++++-------------
>  1 files changed, 18 insertions(+), 17 deletions(-)
> 
> diff --git a/lib/libdvbv5/descriptors/desc_t2_delivery.c b/lib/libdvbv5/descriptors/desc_t2_delivery.c
> index ab4361d..07a0956 100644
> --- a/lib/libdvbv5/descriptors/desc_t2_delivery.c
> +++ b/lib/libdvbv5/descriptors/desc_t2_delivery.c
> @@ -32,6 +32,7 @@ void dvb_desc_t2_delivery_init(struct dvb_v5_fe_parms *parms,
>  	struct dvb_desc_t2_delivery *d = desc;
>  	unsigned char *p = (unsigned char *) buf;
>  	size_t desc_len = ext->length - 1, len, len2;
> +	uint8_t nmemb;
>  	int i;
>  
>  	len = offsetof(struct dvb_desc_t2_delivery, bitfield);
> @@ -42,7 +43,7 @@ void dvb_desc_t2_delivery_init(struct dvb_v5_fe_parms *parms,
>  		return;
>  	}
>  	if (desc_len < len2) {
> -		memcpy(p, buf, len);
> +		memcpy(d, p, len);
>  		bswap16(d->system_id);
>  
>  		if (desc_len != len)
> @@ -50,44 +51,41 @@ void dvb_desc_t2_delivery_init(struct dvb_v5_fe_parms *parms,
>  
>  		return;
>  	}
> -	memcpy(p, buf, len2);
> +	memcpy(d, p, len2);
>  	p += len2;
>  
> -	len = desc_len - (p - buf);
> -	memcpy(&d->centre_frequency, p, len);
> -	p += len;
> -
>  	if (d->tfs_flag)
> -		d->frequency_loop_length = 1;
> +		d->frequency_loop_length = sizeof(*d->centre_frequency);
>  	else {
>  		d->frequency_loop_length = *p;
>  		p++;
>  	}
> +	nmemb = d->frequency_loop_length / sizeof(*d->centre_frequency);
>  
> -	d->centre_frequency = calloc(d->frequency_loop_length,
> -				     sizeof(*d->centre_frequency));
> +	d->centre_frequency = calloc(nmemb, sizeof(*d->centre_frequency));
>  	if (!d->centre_frequency) {
>  		dvb_perror("Out of memory");
>  		return;
>  	}
>  
> -	memcpy(d->centre_frequency, p, sizeof(*d->centre_frequency) * d->frequency_loop_length);
> -	p += sizeof(*d->centre_frequency) * d->frequency_loop_length;
> +	memcpy(d->centre_frequency, p, d->frequency_loop_length);
> +	p += d->frequency_loop_length;
>  
> -	for (i = 0; i < d->frequency_loop_length; i++)
> +	for (i = 0; i < nmemb; i++)
>  		bswap32(d->centre_frequency[i]);
>  
>  	d->subcel_info_loop_length = *p;
>  	p++;
> +	nmemb = d->subcel_info_loop_length / sizeof(*d->subcell);
>  
> -	d->subcell = calloc(d->subcel_info_loop_length, sizeof(*d->subcell));
> +	d->subcell = calloc(nmemb, sizeof(*d->subcell));
>  	if (!d->subcell) {
>  		dvb_perror("Out of memory");
>  		return;
>  	}
> -	memcpy(d->subcell, p, sizeof(*d->subcell) * d->subcel_info_loop_length);
> +	memcpy(d->subcell, p, d->subcel_info_loop_length);
>  
> -	for (i = 0; i < d->subcel_info_loop_length; i++)
> +	for (i = 0; i < nmemb; i++)
>  		bswap16(d->subcell[i].transposer_frequency);
>  }
>  
> @@ -97,6 +95,7 @@ void dvb_desc_t2_delivery_print(struct dvb_v5_fe_parms *parms,
>  {
>  	const struct dvb_desc_t2_delivery *d = desc;
>  	int i;
> +	uint8_t nmemb;
>  
>  	dvb_log("|       DVB-T2 delivery");
>  	dvb_log("|           plp_id                    %d", d->plp_id);
> @@ -113,10 +112,12 @@ void dvb_desc_t2_delivery_print(struct dvb_v5_fe_parms *parms,
>  	dvb_log("|           bandwidth                 %d", d->bandwidth);
>  	dvb_log("|           SISO MISO                 %d", d->SISO_MISO);
>  
> -	for (i = 0; i < d->frequency_loop_length; i++)
> +	nmemb = d->frequency_loop_length / sizeof(*d->centre_frequency);
> +	for (i = 0; i < nmemb; i++)
>  		dvb_log("|           centre frequency[%d]   %d", i, d->centre_frequency[i]);
>  
> -	for (i = 0; i < d->subcel_info_loop_length; i++) {
> +	nmemb = d->subcel_info_loop_length / sizeof(*d->subcell);
> +	for (i = 0; i < nmemb; i++) {
>  		dvb_log("|           cell_id_extension[%d]  %d", i, d->subcell[i].cell_id_extension);
>  		dvb_log("|           transposer frequency   %d", d->subcell[i].transposer_frequency);
>  	}


-- 

Cheers,
Mauro

Re: [PATCH] libdvbv5: more fixes in the T2 delivery descriptor handler

[Nikolaus Schulz]

Hi Mauro,

I didn't have the time yet to look at your comments and that patch
again, but:

Please note that my email address <schulz@macnetix.de> is shut down as
of today[1].

Please use my alternate address, <ns@htonl.de>, for any further replies
or followups.

Maybe Patchwork[2] should also be updated accordingly?

Thanks,
Nikolaus

[1] I don't know if the local admin will disable the old email address
    <schulz@macnetix.de> in time, but I definitely will no longer read
    messages sent to it, from now on.
[2] https://patchwork.linuxtv.org/patch/20943/

Re: [PATCH] libdvbv5: more fixes in the T2 delivery descriptor handler

[Mauro Carvalho Chehab]

Em Thu, 19 Dec 2013 03:37:48 +0100
Nikolaus Schulz <schulz@macnetix.de> escreveu:

> Hi Mauro,
> 
> I didn't have the time yet to look at your comments and that patch
> again, but:
> 
> Please note that my email address <schulz@macnetix.de> is shut down as
> of today[1].
> 
> Please use my alternate address, <ns@htonl.de>, for any further replies
> or followups.

Ok. Well, if anyone replies to the thread, it will to to both addresses,
so it should reach you anyway.

> Maybe Patchwork[2] should also be updated accordingly?

I think that you'll need to create an account at patchwork, in order
to add your new address. Not sure if it allows you to delete the
old address through.

> 
> Thanks,
> Nikolaus
> 
> [1] I don't know if the local admin will disable the old email address
>     <schulz@macnetix.de> in time, but I definitely will no longer read
>     messages sent to it, from now on.
> [2] https://patchwork.linuxtv.org/patch/20943/


-- 

Cheers,
Mauro

Re: [PATCH] libdvbv5: more fixes in the T2 delivery descriptor handler

[Nikolaus Schulz]

On Wed, Dec 18, 2013 at 10:49:31AM -0200, Mauro Carvalho Chehab wrote:
> > * Properly use lengths of centre_frequency loop and subcell_info loop
> >   (they count bytes, not entries)
> 
> I'm not sure about this one. On all other similar descriptors, we're storing
> the number of elements at the descriptor's structure, instead of its size,
> as that makes easier to handle them.

OK, I had been looking into other descriptor handlers and didn't spot
anything like that, but isdbt_desc_terrestrial_delivery_system.num_freqs
at least indeed does count array members.

> Also, having all delivery_system descriptors using the number of elements
> makes easier to avoid confusion when writing the handling code.

I agree, it also is way more natural.  Actually I felt that from the
start, but considering that the structs in the code very closely
correlate to the binary DVBSI format, I adopted the byte count
accordingly.

> Btw, I think that this change will likely break the code that handles this
> descriptor at dvb-scan.

Indeed, add_update_nit_dvbt2() would be affected.

> So, could you please redo your patch in order for it to keep storing the
> number of elements at the dvb_desc_t2_delivery::frequency_loop_length
> field? If you prefer, you can rename it to frequency_loop_nmemb (or a
> similar naming) to make it clearer.

I'll re-send it using frequency_loop_nmemb and subcel_info_loop_nmemb,
in order to avoid confusion with the {frequency,subcell_info}_loop_length
fields in the binary DVBSI format.

Thanks,
Nikolaus

> > Signed-off-by: Nikolaus Schulz <schulz@macnetix.de>
> > ---
> >  lib/libdvbv5/descriptors/desc_t2_delivery.c |   35 ++++++++++++++-------------
> >  1 files changed, 18 insertions(+), 17 deletions(-)
> > 
> > diff --git a/lib/libdvbv5/descriptors/desc_t2_delivery.c b/lib/libdvbv5/descriptors/desc_t2_delivery.c
> > index ab4361d..07a0956 100644
> > --- a/lib/libdvbv5/descriptors/desc_t2_delivery.c
> > +++ b/lib/libdvbv5/descriptors/desc_t2_delivery.c
> > @@ -32,6 +32,7 @@ void dvb_desc_t2_delivery_init(struct dvb_v5_fe_parms *parms,
> >  	struct dvb_desc_t2_delivery *d = desc;
> >  	unsigned char *p = (unsigned char *) buf;
> >  	size_t desc_len = ext->length - 1, len, len2;
> > +	uint8_t nmemb;
> >  	int i;
> >  
> >  	len = offsetof(struct dvb_desc_t2_delivery, bitfield);
> > @@ -42,7 +43,7 @@ void dvb_desc_t2_delivery_init(struct dvb_v5_fe_parms *parms,
> >  		return;
> >  	}
> >  	if (desc_len < len2) {
> > -		memcpy(p, buf, len);
> > +		memcpy(d, p, len);
> >  		bswap16(d->system_id);
> >  
> >  		if (desc_len != len)
> > @@ -50,44 +51,41 @@ void dvb_desc_t2_delivery_init(struct dvb_v5_fe_parms *parms,
> >  
> >  		return;
> >  	}
> > -	memcpy(p, buf, len2);
> > +	memcpy(d, p, len2);
> >  	p += len2;
> >  
> > -	len = desc_len - (p - buf);
> > -	memcpy(&d->centre_frequency, p, len);
> > -	p += len;
> > -
> >  	if (d->tfs_flag)
> > -		d->frequency_loop_length = 1;
> > +		d->frequency_loop_length = sizeof(*d->centre_frequency);
> >  	else {
> >  		d->frequency_loop_length = *p;
> >  		p++;
> >  	}
> > +	nmemb = d->frequency_loop_length / sizeof(*d->centre_frequency);
> >  
> > -	d->centre_frequency = calloc(d->frequency_loop_length,
> > -				     sizeof(*d->centre_frequency));
> > +	d->centre_frequency = calloc(nmemb, sizeof(*d->centre_frequency));
> >  	if (!d->centre_frequency) {
> >  		dvb_perror("Out of memory");
> >  		return;
> >  	}
> >  
> > -	memcpy(d->centre_frequency, p, sizeof(*d->centre_frequency) * d->frequency_loop_length);
> > -	p += sizeof(*d->centre_frequency) * d->frequency_loop_length;
> > +	memcpy(d->centre_frequency, p, d->frequency_loop_length);
> > +	p += d->frequency_loop_length;
> >  
> > -	for (i = 0; i < d->frequency_loop_length; i++)
> > +	for (i = 0; i < nmemb; i++)
> >  		bswap32(d->centre_frequency[i]);
> >  
> >  	d->subcel_info_loop_length = *p;
> >  	p++;
> > +	nmemb = d->subcel_info_loop_length / sizeof(*d->subcell);
> >  
> > -	d->subcell = calloc(d->subcel_info_loop_length, sizeof(*d->subcell));
> > +	d->subcell = calloc(nmemb, sizeof(*d->subcell));
> >  	if (!d->subcell) {
> >  		dvb_perror("Out of memory");
> >  		return;
> >  	}
> > -	memcpy(d->subcell, p, sizeof(*d->subcell) * d->subcel_info_loop_length);
> > +	memcpy(d->subcell, p, d->subcel_info_loop_length);
> >  
> > -	for (i = 0; i < d->subcel_info_loop_length; i++)
> > +	for (i = 0; i < nmemb; i++)
> >  		bswap16(d->subcell[i].transposer_frequency);
> >  }
> >  
> > @@ -97,6 +95,7 @@ void dvb_desc_t2_delivery_print(struct dvb_v5_fe_parms *parms,
> >  {
> >  	const struct dvb_desc_t2_delivery *d = desc;
> >  	int i;
> > +	uint8_t nmemb;
> >  
> >  	dvb_log("|       DVB-T2 delivery");
> >  	dvb_log("|           plp_id                    %d", d->plp_id);
> > @@ -113,10 +112,12 @@ void dvb_desc_t2_delivery_print(struct dvb_v5_fe_parms *parms,
> >  	dvb_log("|           bandwidth                 %d", d->bandwidth);
> >  	dvb_log("|           SISO MISO                 %d", d->SISO_MISO);
> >  
> > -	for (i = 0; i < d->frequency_loop_length; i++)
> > +	nmemb = d->frequency_loop_length / sizeof(*d->centre_frequency);
> > +	for (i = 0; i < nmemb; i++)
> >  		dvb_log("|           centre frequency[%d]   %d", i, d->centre_frequency[i]);
> >  
> > -	for (i = 0; i < d->subcel_info_loop_length; i++) {
> > +	nmemb = d->subcel_info_loop_length / sizeof(*d->subcell);
> > +	for (i = 0; i < nmemb; i++) {
> >  		dvb_log("|           cell_id_extension[%d]  %d", i, d->subcell[i].cell_id_extension);
> >  		dvb_log("|           transposer frequency   %d", d->subcell[i].transposer_frequency);
> >  	}