Re: [PATCH v5] app/test: secondary process passes allow parameters

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Nov 10, 2023 at 10:30:12AM +0000, Mingjin Ye wrote:
> In EAL related test cases, the allow parameters are not passed to
> the secondary process, resulting in unexpected NICs being loaded.
> 
> This patch fixes this issue by appending the allow parameters to
> the secondary process.
> 
> Fixes: af75078fece3 ("first public release")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Mingjin Ye <mingjinx.ye@intel.com>

Some additional comments below. Sorry I missed out on them in my first
review.

/Bruce

> ---
> v5: Optimized.
> ---
>  app/test/process.h | 74 +++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 70 insertions(+), 4 deletions(-)
> 
> diff --git a/app/test/process.h b/app/test/process.h
> index af7bc3e0de..f8beb3c36f 100644
> --- a/app/test/process.h
> +++ b/app/test/process.h
> @@ -18,6 +18,8 @@
>  
>  #include <rte_string_fns.h> /* strlcpy */
>  
> +#include <rte_devargs.h>
> +
>  #ifdef RTE_EXEC_ENV_FREEBSD
>  #define self "curproc"
>  #define exe "file"
> @@ -34,6 +36,57 @@ extern uint16_t flag_for_send_pkts;
>  #endif
>  #endif
>  
> +#define PREFIX_ALLOW "--allow="
> +
> +static int
> +add_parameter_allow(char **argv, int max_capacity)
> +{
> +	struct rte_devargs *devargs;
> +	int count = 0;
> +	char *dev;
> +	int malloc_size;
> +	int allow_size = strlen(PREFIX_ALLOW);
> +	int offset;
> +
> +	RTE_EAL_DEVARGS_FOREACH(NULL, devargs) {
> +		int name_length = 0;
> +		int data_length = 0;
> +
> +		if (count >= max_capacity)
> +			return count;
> +
> +		name_length = strlen(devargs->name);
> +		if (name_length == 0)
> +			continue;
> +
> +		if (devargs->data != NULL)
> +			data_length = strlen(devargs->data);
> +		else
> +			data_length = 0;
> +
> +		malloc_size = allow_size + name_length + data_length + 1;
> +		dev = malloc(malloc_size);
> +		if (!dev)
> +			return count;
> +
> +		offset = 0;
> +		memcpy(dev + offset, PREFIX_ALLOW, allow_size);
> +		offset += allow_size;
> +		memcpy(dev + offset, devargs->name, name_length);
> +		offset += name_length;
> +		if (data_length > 0) {
> +			memcpy(dev + offset, devargs->data, data_length);

Do we need a comma "," before devargs->data in the output string?

> +			offset += data_length;
> +		}
> +		memset(dev + offset, 0x00, 1);
> +
> +		*(argv + count) = dev;
> +		count++;
> +	}
> +

Sorry for the late feedback, but I believe this whole block can be
hugely simplified by using asprintf.

	RTE_EAL_DEVARGS_FOREACH(NULL, devargs) {
		if (devargs->data == NULL) {
			if (asprintf(&argv[count], PREFIX_ALLOW"%s", devargs->name) < 0)
				break;
		} else {
			if (asprintf(&argv[count], PREFIX_ALLOW"%s,%s",
					 devargs->name, devargs->data) < 0)
				break;
		}
		if (++count == max_capacity)
			break;
	}

This way, the only variables you actually need are devargs and count.

> +	return count;
> +}
> +
>  /*
>   * launches a second copy of the test process using the given argv parameters,
>   * which should include argv[0] as the process name. To identify in the
> @@ -44,7 +97,9 @@ static inline int
>  process_dup(const char *const argv[], int numargs, const char *env_value)
>  {
>  	int num;
> -	char *argv_cpy[numargs + 1];
> +	char **argv_cpy;
> +	int allow_num;
> +	int argv_num;
>  	int i, status;
>  	char path[32];
>  #ifdef RTE_LIB_PDUMP
> @@ -58,12 +113,17 @@ process_dup(const char *const argv[], int numargs, const char *env_value)
>  	if (pid < 0)
>  		return -1;
>  	else if (pid == 0) {
> +		allow_num = rte_devargs_type_count(RTE_DEVTYPE_ALLOWED);
> +		argv_num = numargs + allow_num + 1;
> +		argv_cpy = malloc(argv_num * sizeof(char *));

Check return from malloc.

>  		/* make a copy of the arguments to be passed to exec */
>  		for (i = 0; i < numargs; i++)
>  			argv_cpy[i] = strdup(argv[i]);
> -		argv_cpy[i] = NULL;
> -		num = numargs;
> -
> +		num = add_parameter_allow(&argv_cpy[i], allow_num);
> +		if (num != allow_num)
> +			rte_panic("Fill allow parameter incomplete\n");
> +		num += numargs;
> +		argv_cpy[argv_num - 1] = NULL;
>  #ifdef RTE_EXEC_ENV_LINUX
>  		{
>  			const char *procdir = "/proc/" self "/fd/";
> @@ -131,6 +191,12 @@ process_dup(const char *const argv[], int numargs, const char *env_value)
>  			}
>  			rte_panic("Cannot exec: %s\n", strerror(errno));
>  		}
> +
> +		for (i = 0; i < num; i++) {
> +			if (argv_cpy[i] != NULL)
> +				free(argv_cpy[i]);

Free is ok to call with NULl, so you can skip the check and just do

	for (i = 0; i < num; i++)
		free(argv_cpy[i]);

> +		}
> +		free(argv_cpy);
>  	}
>  	/* parent process does a wait */
>  #ifdef RTE_LIB_PDUMP
> -- 
> 2.25.1
>