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

[Petr Vorel]

Hi Li,

> In tst_kconfig.c, it adds the tst_kcmdline_parse function to
> read and parse command-line parameters from /proc/cmdline.
> This function tokenizes the command line, matches keys with
> the provided parameter array, and stores the associated values.
> The update enhances the testing framework's ability to handle
> kernel configuration parameters dynamically.

> Signed-off-by: Li Wang <liwang@redhat.com>
> ---
>  include/tst_kconfig.h | 23 +++++++++++++++++++++++
>  lib/tst_kconfig.c     | 41 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 64 insertions(+)

> diff --git a/include/tst_kconfig.h b/include/tst_kconfig.h
> index 8b24a8380..0ecf2c0d1 100644
> --- a/include/tst_kconfig.h
> +++ b/include/tst_kconfig.h
> @@ -64,4 +64,27 @@ 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_param 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 = "" \
> +}
> +
> +/* Structure for storing command-line parameter key and its corresponding value */
> +struct tst_kcmdline_param {
> +	const char *key;
> +	char value[128];
> +};
> +
> +/**
> + * Parses command-line parameters from /proc/cmdline and stores them in params array
> + * params: The array of tst_kcmdline_param 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_param params[], size_t params_len);
> +
>  #endif	/* TST_KCONFIG_H__ */
> diff --git a/lib/tst_kconfig.c b/lib/tst_kconfig.c
> index 595ea4b09..f79dea5c6 100644
> --- a/lib/tst_kconfig.c
> +++ b/lib/tst_kconfig.c
> @@ -565,3 +565,44 @@ char tst_kconfig_get(const char *confname)

>  	return var.choice;
>  }
> +
> +void tst_kcmdline_parse(struct tst_kcmdline_param params[], size_t params_len) {
> +	FILE *proc_cmdline;
> +	char cmdline[4096];
> +	char *token, *key, *value;
> +
> +	proc_cmdline = fopen("/proc/cmdline", "r");
Why not SAFE_FOPEN() ?
> +	if (proc_cmdline == NULL)
> +		tst_brk(TBROK | TERRNO, "Failed to open /proc/cmdline for reading");
> +
> +	if (fgets(cmdline, sizeof(cmdline), proc_cmdline) == NULL) {
> +		fclose(proc_cmdline);
Maybe SAFE_FCLOSE() ?
> +
> +		if (feof(proc_cmdline))
tst_kconfig.c:581:21: warning: pointer ‘proc_cmdline’ used after ‘fclose’ [-Wuse-after-free]
  581 |                 if (feof(proc_cmdline))
      |                     ^~~~~~~~~~~~~~~~~~
tst_kconfig.c:579:17: note: call to ‘fclose’ here
  579 |                 fclose(proc_cmdline);
      |                 ^~~~~~~~~~~~~~~~~~~~

> +			tst_brk(TBROK, "End-of-File reached on /proc/cmdline without reading any data");
> +		else
> +			tst_brk(TBROK | TERRNO, "Failed to read from /proc/cmdline");
> +	}
> +	fclose(proc_cmdline);
Maybe SAFE_FCLOSE() ?

Kind regards,
Petr

> +
> +	token = strtok(cmdline, " ");
> +	while (token != NULL) {
> +		key = token;
> +		value = strchr(token, '=');
> +
> +		if (value != NULL) {
> +			/* Split the token into key and value at '=' */
> +			*value++ = '\0';
> +
> +			for (size_t i = 0; i < params_len; i++) {
> +				if (strcmp(params[i].key, key) == 0) {
> +					strncpy(params[i].value, value, sizeof(params[i].value) - 1);
> +					params[i].value[sizeof(params[i].value) - 1] = '\0';
> +					break;
> +				}
> +			}
> +		}
> +
> +		token = strtok(NULL, " ");
> +	}
> +}