[LTP] [PATCH v3 1/3] kconfig: add funtion to parse /proc/cmdline

[Petr Vorel]

Hi Li,

> A new structure tst_kcmdline_var is defined to hold a command-line
> argument's key and a fixed-size value. Furthermore, function
> tst_kcmdline_parse is added to the corresponding .c file, which
> reads from /proc/cmdline, parses the command-line arguments, and
> populates the tst_kcmdline_var array with the obtained key-value
> pairs, ensuring safe file operations and buffer size checks.

Nice. Just compiler warning and formatting nits below (just fix them before merge).
Thanks a lot for adding a test.

Reviewed-by: Petr Vorel <pvorel@suse.cz>

> Signed-off-by: Li Wang <liwang@redhat.com>
> ---
>  include/tst_kconfig.h             | 29 ++++++++++++++
>  lib/newlib_tests/test_kconfig03.c | 40 +++++++++++++++++++
>  lib/tst_kconfig.c                 | 66 +++++++++++++++++++++++++++++++
>  3 files changed, 135 insertions(+)
>  create mode 100644 lib/newlib_tests/test_kconfig03.c

> diff --git a/include/tst_kconfig.h b/include/tst_kconfig.h
> index 8b24a8380..bbb899784 100644
> --- a/include/tst_kconfig.h
> +++ b/include/tst_kconfig.h
> @@ -6,6 +6,8 @@
>  #ifndef TST_KCONFIG_H__
>  #define TST_KCONFIG_H__

> +#include <stdbool.h>
> +
>  /**
>   * Initialization helper macro for struct tst_kconfig_var. Requires <string.h>
very nic: missing dot at the end.
>   */
> @@ -64,4 +66,31 @@ void tst_kconfig_read(struct tst_kconfig_var vars[], size_t vars_len);
>   */
>  int tst_kconfig_check(const char *const kconfigs[]);

> +/**
> + * Macro to initialize a tst_kcmdline_var structure with a specified parameter
> + * name and an empty value. This is useful for setting up an array of parameter
> + * structures before parsing the actual command-line arguments.
> + */
> +#define TST_KCMDLINE_INIT(paraname) { \
> +	.key = paraname, \
> +	.value = "", \
> +	.found = false \
> +}
> +
> +/**
> + * Structure for storing command-line parameter key and its corresponding value
and here.

> + */
> +struct tst_kcmdline_var {
> +	const char *key;
> +	char value[128];
> +	bool found;
> +};
> +
> +/**
> + * Parses command-line parameters from /proc/cmdline and stores them in params array.
> + * params: The array of tst_kcmdline_var structures to be filled with parsed key-value pairs.
> + * params_len: The length of the params array, indicating how many parameters to parse.
> + */
> +void tst_kcmdline_parse(struct tst_kcmdline_var params[], size_t params_len);
> +
>  #endif	/* TST_KCONFIG_H__ */
> diff --git a/lib/newlib_tests/test_kconfig03.c b/lib/newlib_tests/test_kconfig03.c
> new file mode 100644
> index 000000000..937c2b29c
> --- /dev/null
> +++ b/lib/newlib_tests/test_kconfig03.c
> @@ -0,0 +1,40 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2024 Li Wang <liwang@redhat.com>
> + */
> +
> +#include "tst_test.h"
> +#include "tst_kconfig.h"
> +
> +static struct tst_kcmdline_var params[] = {
> +	TST_KCMDLINE_INIT("BOOT_IMAGE"),
> +	TST_KCMDLINE_INIT("root"),
> +	TST_KCMDLINE_INIT("foo")
> +};
> +
> +static void do_test(void)
> +{
> +	int i, N;
> +
> +	N = (int) ARRAY_SIZE(params);
> +
> +	tst_kcmdline_parse(params, N);
> +
> +	for (i = 0; i < N; i++) {
> +		if (params[i].found) {
> +			if (params[i].value)

test_kconfig03.c:25:29: warning: the comparison will always evaluate as ‘true’ for the address of ‘value’ will never be NULL [-Waddress]
   25 |                         if (params[i].value)
      |                             ^~~~~~
In file included from test_kconfig03.c:7:
../../include/tst_kconfig.h:85:14: note: ‘value’ declared here
   85 |         char value[128];

It must be:
if (params[i].value[0] != '\0')

Or just without else at all:

	for (i = 0; i < N; i++) {
		if (params[i].found) {
			tst_res(TPASS, "params[%d] = {%s, %s}", i, params[i].key, params[i].value);
		} else {
			if (!strcmp(params[i].key, "foo"))
				tst_res(TPASS, "%s is not found in /proc/cmdline", params[i].key);
			else
				tst_res(TFAIL, "%s is not found in /proc/cmdline", params[i].key);
		}

Kind regards,
Petr

> +				tst_res(TPASS, "params[%d] = {%s, %s}", i, params[i].key, params[i].value);
> +			else
> +				tst_res(TPASS, "params[%d] = {%s, no value}", i, params[i].key);
> +		} else {
> +			if (!strcmp(params[i].key, "foo"))
> +				tst_res(TPASS, "%s is not found in /proc/cmdline", params[i].key);
> +			else
> +				tst_res(TFAIL, "%s is not found in /proc/cmdline", params[i].key);
> +		}
> +	}
> +}
...