[v2,1/2] testcase: lib: Create tst_getconf to replace "getconf"

In some system, "getconf" application may not be installed.
Some tests are using it to retrieve some variables such as the
page size (PAGESIZE).

Create a tst_getconf binary that use sysconf() function to retrieve
these variables instead of relying on "getconf" application that
may not be available.
Add also this new helper in the documentation.

Example:
pagesize=`tst_getconf PAGESIZE`

Signed-off-by: Mylène Josserand <mylene.josserand@bootlin.com>
---
 doc/test-writing-guidelines.txt | 14 +++++++++
 testcases/lib/.gitignore        |  1 +
 testcases/lib/Makefile          |  3 +-
 testcases/lib/tst_getconf.c     | 66 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 testcases/lib/tst_getconf.c

Hi Mylene,

On Thu, Jun 14, 2018 at 3:22 PM, Mylène Josserand
<mylene.josserand@bootlin.com> wrote:
> In some system, "getconf" application may not be installed.
> Some tests are using it to retrieve some variables such as the
> page size (PAGESIZE).
>
> Create a tst_getconf binary that use sysconf() function to retrieve
> these variables instead of relying on "getconf" application that
> may not be available.
> Add also this new helper in the documentation.
>
> Example:
> pagesize=`tst_getconf PAGESIZE`
>
> Signed-off-by: Mylène Josserand <mylene.josserand@bootlin.com>
Reviewed-by: Li Wang <liwang@redhat.com>
> ---
>  doc/test-writing-guidelines.txt | 14 +++++++++
>  testcases/lib/.gitignore        |  1 +
>  testcases/lib/Makefile          |  3 +-
>  testcases/lib/tst_getconf.c     | 66 +++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 83 insertions(+), 1 deletion(-)
>  create mode 100644 testcases/lib/tst_getconf.c
>
> diff --git a/doc/test-writing-guidelines.txt b/doc/test-writing-guidelines.txt
> index fb7dcb591..e42451fae 100644
> --- a/doc/test-writing-guidelines.txt
> +++ b/doc/test-writing-guidelines.txt
> @@ -1630,6 +1630,20 @@ passed directly to the script in '$1', '$2', ..., '$n'.
>  2.3.4 Usefull library functions
>  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> +Retrieving configuration variables
> +++++++++++++++++++++++++++++++++++
> +
> +You may need to retrieve some variable configuration such as PAGESIZE.
> +There is "getconf" application that allows that but as some system may not
> +have it, a "tst_getconf" library allows to retrieve these variables by using
> +"sysconf()" function.
> +
> +[source,sh]
> +-------------------------------------------------------------------------------
> +# retrieve PAGESIZE
> +pagesize=`tst_getconf PAGESIZE`
> +-------------------------------------------------------------------------------
> +
>  Sleeping for subsecond intervals
>  ++++++++++++++++++++++++++++++++
>
> diff --git a/testcases/lib/.gitignore b/testcases/lib/.gitignore
> index f36ed99fa..997940006 100644
> --- a/testcases/lib/.gitignore
> +++ b/testcases/lib/.gitignore
> @@ -7,3 +7,4 @@
>  /tst_net_iface_prefix
>  /tst_net_ip_prefix
>  /tst_net_vars
> +/tst_getconf
> \ No newline at end of file
> diff --git a/testcases/lib/Makefile b/testcases/lib/Makefile
> index 398150ae0..77b7b2ef1 100644
> --- a/testcases/lib/Makefile
> +++ b/testcases/lib/Makefile
> @@ -27,6 +27,7 @@ include $(top_srcdir)/include/mk/testcases.mk
>  INSTALL_TARGETS                := *.sh
>
>  MAKE_TARGETS           := tst_sleep tst_random tst_checkpoint tst_rod tst_kvcmp\
> -                          tst_device tst_net_iface_prefix tst_net_ip_prefix tst_net_vars
> +                          tst_device tst_net_iface_prefix tst_net_ip_prefix tst_net_vars\
> +                          tst_getconf
>
>  include $(top_srcdir)/include/mk/generic_leaf_target.mk
> diff --git a/testcases/lib/tst_getconf.c b/testcases/lib/tst_getconf.c
> new file mode 100644
> index 000000000..7cdef9f54
> --- /dev/null
> +++ b/testcases/lib/tst_getconf.c
> @@ -0,0 +1,66 @@
> +/*
> + * Copyright (c) 2018 Mylène Josserand <mylene.josserand@bootlin.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software Foundation,
> + * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> + */
> +
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <string.h>
> +
> +static void print_help(void)
> +{
> +       printf("Usage: tst_getconf variable\n\n");
> +       printf("       variable: can be PAGESIZE or _NPROCESSORS_ONLN (for the moment)\n");
> +       printf("example: tst_getconf PAGESIZE\n");
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +       int opt;
> +
> +       while ((opt = getopt(argc, argv, ":h")) != -1) {
> +               switch (opt) {
> +               case 'h':
> +                       print_help();
> +                       return 0;
> +               default:
> +                       print_help();
> +                       return 1;
> +               }
> +       }
> +
> +       if (argc != 2) {
> +               print_help();
> +               return 1;
> +       }
> +
> +       if (optind >= argc) {
> +               fprintf(stderr, "ERROR: Expected variable argument\n\n");
> +               print_help();
> +               return 1;
> +       }
> +
> +       if (!strcmp(argv[optind], "_NPROCESSORS_ONLN"))
> +               printf("%ld", sysconf(_SC_NPROCESSORS_ONLN));
> +       else if (!strcmp(argv[optind],"PAGESIZE"))
> +               printf("%ld", sysconf(_SC_PAGE_SIZE));
> +       else {
> +               printf("Invalid argument");
> +               return -1;
> +       }

To be honest, I prefer to make it more like getconf behavior
especially for the neline or error warning. Which diff with you patch
as following, but without this alignment it would be also accessible I
think.

--- a/testcases/lib/tst_getconf.c
+++ b/testcases/lib/tst_getconf.c
@@ -23,7 +23,7 @@
 static void print_help(void)
 {
        printf("Usage: tst_getconf variable\n\n");
-       printf("       variable: can be PAGESIZE or _NPROCESSORS_ONLN
(for the moment)\n");
+       printf("       variable: can be PAGESIZE/PAGE_SIZE or
_NPROCESSORS_ONLN (for the moment)\n");
        printf("example: tst_getconf PAGESIZE\n");
 }

@@ -54,11 +54,11 @@ int main(int argc, char *argv[])
        }

        if (!strcmp(argv[optind], "_NPROCESSORS_ONLN"))
-               printf("%ld", sysconf(_SC_NPROCESSORS_ONLN));
-       else if (!strcmp(argv[optind],"PAGESIZE"))
-               printf("%ld", sysconf(_SC_PAGE_SIZE));
+               printf("%ld\n", sysconf(_SC_NPROCESSORS_ONLN));
+       else if (!strcmp(argv[optind], "PAGESIZE") ||
!strcmp(argv[optind], "PAGE_SIZE"))
+               printf("%ld\n", sysconf(_SC_PAGE_SIZE));
        else {
-               printf("Invalid argument");
+               printf("tst_getconf: Unrecognized variable \'%s\'\n",
argv[optind]);
                return -1;
        }

> +
> +       return 0;
> +}
> --
> 2.11.0
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp

Hi!
> +You may need to retrieve some variable configuration such as PAGESIZE.
> +There is "getconf" application that allows that but as some system may not
> +have it, a "tst_getconf" library allows to retrieve these variables by using
> +"sysconf()" function.

Shouldn't we stress here that we should use the tst_getconf instead of
getconf here?

Something as:

You may need to retrieve configuration values such as PAGESIZE, there is
'getconf' but as some system may not have it, you are advised to use
'tst_getconf' instead. Note that it implements subset of 'getconf'
system variables used by the testcases only.


> +[source,sh]
> +-------------------------------------------------------------------------------
> +# retrieve PAGESIZE
> +pagesize=`tst_getconf PAGESIZE`
> +-------------------------------------------------------------------------------
> +
>  Sleeping for subsecond intervals
>  ++++++++++++++++++++++++++++++++
>  
> diff --git a/testcases/lib/.gitignore b/testcases/lib/.gitignore
> index f36ed99fa..997940006 100644
> --- a/testcases/lib/.gitignore
> +++ b/testcases/lib/.gitignore
> @@ -7,3 +7,4 @@
>  /tst_net_iface_prefix
>  /tst_net_ip_prefix
>  /tst_net_vars
> +/tst_getconf
> \ No newline at end of file
> diff --git a/testcases/lib/Makefile b/testcases/lib/Makefile
> index 398150ae0..77b7b2ef1 100644
> --- a/testcases/lib/Makefile
> +++ b/testcases/lib/Makefile
> @@ -27,6 +27,7 @@ include $(top_srcdir)/include/mk/testcases.mk
>  INSTALL_TARGETS		:= *.sh
>  
>  MAKE_TARGETS		:= tst_sleep tst_random tst_checkpoint tst_rod tst_kvcmp\
> -			   tst_device tst_net_iface_prefix tst_net_ip_prefix tst_net_vars
> +			   tst_device tst_net_iface_prefix tst_net_ip_prefix tst_net_vars\
> +			   tst_getconf
>  
>  include $(top_srcdir)/include/mk/generic_leaf_target.mk
> diff --git a/testcases/lib/tst_getconf.c b/testcases/lib/tst_getconf.c
> new file mode 100644
> index 000000000..7cdef9f54
> --- /dev/null
> +++ b/testcases/lib/tst_getconf.c
> @@ -0,0 +1,66 @@
> +/*
> + * Copyright (c) 2018 Myl??ne Josserand <mylene.josserand@bootlin.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it would be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write the Free Software Foundation,
> + * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> + */
> +
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <string.h>
> +
> +static void print_help(void)
> +{
> +	printf("Usage: tst_getconf variable\n\n");
> +	printf("       variable: can be PAGESIZE or _NPROCESSORS_ONLN (for the moment)\n");
> +	printf("example: tst_getconf PAGESIZE\n");
> +}
> +
> +int main(int argc, char *argv[])
> +{
> +	int opt;
> +
> +	while ((opt = getopt(argc, argv, ":h")) != -1) {
> +		switch (opt) {
> +		case 'h':
> +			print_help();
> +			return 0;
> +		default:
> +			print_help();
> +			return 1;
> +		}
> +	}
> +
> +	if (argc != 2) {
> +		print_help();
> +		return 1;
> +	}
> +
> +	if (optind >= argc) {
> +		fprintf(stderr, "ERROR: Expected variable argument\n\n");
> +		print_help();
> +		return 1;
> +	}

I doubt that this will ever be true, we do return from main once there
are any options passed, so optind here should be set to 1 and argc == 2
because we checked earlier.

> +	if (!strcmp(argv[optind], "_NPROCESSORS_ONLN"))
> +		printf("%ld", sysconf(_SC_NPROCESSORS_ONLN));
> +	else if (!strcmp(argv[optind],"PAGESIZE"))
> +		printf("%ld", sysconf(_SC_PAGE_SIZE));
> +	else {
> +		printf("Invalid argument");
                                        ^
					Missing newline
> +		return -1;
> +	}

LKML coding style prefers to have curly braces around both (all) blocks
if they are around one of them, hence this should rather be:

if (...) {

} else if (...) {

} else {

}