Re: [dpdk-dev] [PATCH v7] app/testpmd: add portlist option

["Govindharajan, Hariprasad" <hariprasad.govindharajan@intel.com>]

> -----Original Message-----
> From: Burakov, Anatoly <anatoly.burakov@intel.com>
> Sent: Tuesday, February 11, 2020 12:01 PM
> To: Govindharajan, Hariprasad <hariprasad.govindharajan@intel.com>; Lu,
> Wenzhuo <wenzhuo.lu@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>;
> Iremonger, Bernard <bernard.iremonger@intel.com>; Mcnamara, John
> <john.mcnamara@intel.com>; Kovacevic, Marko
> <marko.kovacevic@intel.com>
> Cc: dev@dpdk.org; Yigit, Ferruh <ferruh.yigit@intel.com>;
> stephen@networkplumber.org; david.marchand@redhat.com
> Subject: Re: [dpdk-dev] [PATCH v7] app/testpmd: add portlist option
> 
> On 10-Feb-20 5:19 PM, Hariprasad Govindharajan wrote:
> > In current version, we are setting the ports using portmask. With
> > portmask, we can use only upto 64 ports. This portlist option enables
> > the user to use more than 64 ports.
> > Now we can specify the ports in 2 different ways
> >   - Using portmask (-p [0x]nnn): mask must be in hex format
> >   - Using portlist in the following format
> >   --portlist <p1>[-p2][,p3[-p4],...]
> >
> >   --portmask 0x2 is same as --portlist 1
> >   --portmask 0x3 is same as --portlist 0-1
> >
> > Signed-off-by: Hariprasad Govindharajan
> > <hariprasad.govindharajan@intel.com>
> > ---
> > v7:
> > moved the port validation outside the parser function.
> > added meaningful comments describing the new functionality.
> > renamed the variables with meaningful names
> >
> > v6:
> > optimized the code to check for duplicates
> >
> > v5:
> > added a check to validate the ports available before setting them.
> > also added comments in the testpmd file for the new function
> >
> > v4:
> > the parser is modified so that we don't ues 2 arrays to convert the
> > listed port values
> >
> > v3:
> > squashed the 2 patches and made it 1 patch with changes only in
> > testpmd. Also working on optmizing the parser
> >
> > v2:
> > moved the parser function to testpmd
> > ---
> >   app/test-pmd/config.c                 | 114
> ++++++++++++++++++++++++++++++++++
> >   app/test-pmd/parameters.c             |   5 ++
> >   app/test-pmd/testpmd.h                |   3 +
> >   doc/guides/testpmd_app_ug/run_app.rst |   7 +++
> >   4 files changed, 129 insertions(+)
> >
> > diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c index
> > 9669cbd..962984b 100644
> > --- a/app/test-pmd/config.c
> > +++ b/app/test-pmd/config.c
> > @@ -2587,6 +2587,120 @@ set_fwd_ports_list(unsigned int *portlist,
> unsigned int nb_pt)
> >   	}
> >   }
> >
> > +/**
> > + * Parse the user input and obtain the list of forwarding ports
> > + *
> > + * @param[in] list
> > + *   String containing the user input. User can specify
> > + *   in these formats 1,3,5 or 1-3 or 1-2,5 or 3,5-6.
> > + *   For example, if the user wants to use all the available
> > + *   4 ports in his system, then the input can be 0-3 or 0,1,2,3.
> > + *   If the user wants to use only the ports 1,2 then the input
> > + *   is 1,2.
> > + *   valid characters are '-' and ','
> > + *   invalid chars like '.' or '#' will result in
> > + *   EAL: Error - exiting with code: 1
> > + *     Cause: Invalid fwd port list
> > + * @param[out] values
> > + *   This array will be filled with a list of port IDs
> > + *   based on the user input
> > + *   Note that duplicate entries are discarded and only the first
> > + *   count entries in this array are port IDs and all the rest
> > + *   will contain default values
> > + * @param[in] maxsize
> > + *   This parameter denotes 2 things
> > + *   1) Size of the values array
> 
> I believe you meant "number", not "size".

[Govindharajan, Hariprasad] Nope. Here I meant to say the maximum size of the values array.
  
> 
> > + *   2) Maximum value of each element in the values array
> > + * @return
> > + *   -On success, returns total count of port IDs
> > + *   -On failure, returns -1.
> > + */
> > +static int
> > +parse_port_list(const char *list, unsigned int *values, int maxsize)
> > +{
> > +	int count = 0;
> > +	char *end = NULL;
> > +	int min, max;
> > +	int value, i;
> > +	unsigned int marked[maxsize];
> > +
> > +	for (i = 0; i < maxsize; i++)
> > +		marked[i] = 0;
> 
> Wouldn't marked[maxsize] = {0}; work the same?

[Govindharajan, Hariprasad] Nope. For that to work, the array size should be a constant. Here it is a variable.
> 
> > +
> > +	if (list == NULL || values == NULL || maxsize < 0)
> > +		return -1;
> 
> You're checking if maxsize can be negative. First of all, you've already
> allocated the array with negative size by this time (the "marked[maxsize]"
> one), second, why allow negative values at all? Why not just make it
> unsigned?
> 
> > +
> > +	/* Remove all blank characters ahead */
> > +	while (isblank(*list))
> > +		list++;
> 
> Why do it here when you do this first thing in the do..while loop anyway?

[Govindharajan, Hariprasad] Yes. Removed.
> 
> > +
> > +	min = maxsize;
> 
> You're overwriting this value regardless. Why not 0? If you want to know for
> sure that the value either has or has not been modified, the conventional
> way to do this is to use INT_MAX from <limits.h>.
> 
> > +
> > +	do {
> > +		while (isblank(*list))
> > +			list++;
> 
> I have a suspicion that isblank() will not return 'true' on '\0' so there's
> probably a buffer overrun here, if you try to dereference *list while going
> past '\0'.

[Govindharajan, Hariprasad]  Corrected
> 
> > +		if (*list == '\0')
> > +			return -1;
> > +		errno = 0;
> > +		value = strtol(list, &end, 10);
> > +		if (errno || end == NULL)
> > +			return -1;
> > +		if (value < 0 || value >= maxsize)
> > +			return -1;
> > +		while (isblank(*end))
> > +			end++;
> > +		if (*end == '-') {
> > +			min = value;
> > +		} else if ((*end == ',') || (*end == '\0')) {
> > +			max = value;
> > +			if (min == maxsize)
> > +				min = value;
> > +			for (i = min; i <= max; i++) {
> > +				if (count < maxsize) {
> > +					if (marked[i])
> > +						continue;
> > +					values[count] = i;
> > +					marked[i] = 1;
> > +					count++;
> > +				}
> > +			}
> > +			min = maxsize;
> 
> Probably clearer to reset both to zero or INT_MAX/INT_MIN?

[Govindharajan, Hariprasad]  done
> 
> > +		} else
> > +			return -1;
> > +		list = end + 1;
> > +	} while (*end != '\0');
> > +
> > +	if (count == 0)
> > +		return -1;
> > +	return count;
> > +}
> > +
> > +void
> > +parse_fwd_portlist(const char *portlist) {
> > +	int portcount;
> > +	unsigned int portindex[RTE_MAX_ETHPORTS];
> > +	int i, valid_port_count = 0;
> 
> unsigned?

[Govindharajan, Hariprasad] Changed. Initially I was comparing those 2 variables with a signed variable,
So declared them as signed as well.
> 
> > +
> > +	portcount = parse_port_list(portlist, portindex,
> RTE_MAX_ETHPORTS);
> > +	if (portcount < 0)
> > +		rte_exit(EXIT_FAILURE, "Invalid fwd port list\n");
> > +
> > +	/*
> > +	 * Here we verify the validity of the ports
> > +	 * and thereby calculate the total number of
> > +	 * valid ports
> > +	 */
> 
> --
> Thanks,
> Anatoly