Re: [PATCH v7 4/4] boot/param: add pointer to next argument to unknown parameter callback

[Michael Ellerman <mpe@ellerman.id.au>]

Michal Suchanek <msuchanek@suse.de> writes:

> The fadump parameter processing re-does the logic of next_arg quote
> stripping to determine where the argument ends. Pass pointer to the
> next argument instead to make this more robust.
>
> Signed-off-by: Michal Suchanek <msuchanek@suse.de>
> ---
>  arch/powerpc/kernel/fadump.c  | 13 +++++--------
>  arch/powerpc/mm/hugetlbpage.c |  4 ++--
>  include/linux/moduleparam.h   |  2 +-
>  init/main.c                   | 12 ++++++------
>  kernel/module.c               |  4 ++--
>  kernel/params.c               | 19 +++++++++++--------
>  lib/dynamic_debug.c           |  2 +-
>  7 files changed, 28 insertions(+), 28 deletions(-)

Can you split out a patch that adds the next argument and updates the
callers. And then a patch for the fadump to use the new arg.

cheers

> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index d7da4ce9f7ae..6ef96711ee9a 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -474,13 +474,14 @@ struct param_info {
>  };
>  
>  static void __init fadump_update_params(struct param_info *param_info,
> -					char *param, char *val)
> +					char *param, char *val, char *next)
>  {
>  	ptrdiff_t param_offset = param - param_info->tmp_cmdline;
>  	size_t vallen = val ? strlen(val) : 0;
>  	char *tgt = param_info->cmdline + param_offset +
>  		FADUMP_EXTRA_ARGS_LEN - param_info->shortening;
> -	int shortening = 0;
> +	int shortening = ((next - 1) - (param))
> +		- (FADUMP_EXTRA_ARGS_LEN + 1 + vallen);
>  
>  	if (!val)
>  		return;
> @@ -488,10 +489,6 @@ static void __init fadump_update_params(struct param_info *param_info,
>  	/* remove '=' */
>  	*tgt++ = ' ';
>  
> -	/* next_arg removes one leading and one trailing '"' */
> -	if ((*tgt == '"') && (*(tgt + vallen + shortening) == '"'))
> -		shortening += 2;
> -
>  	/* remove one leading and one trailing quote if both are present */
>  	if ((val[0] == '"') && (val[vallen - 1] == '"')) {
>  		shortening += 2;
> @@ -517,7 +514,7 @@ static void __init fadump_update_params(struct param_info *param_info,
>   * to enforce the parameters passed through it
>   */
>  static int __init fadump_rework_cmdline_params(char *param, char *val,
> -					       const char *unused, void *arg)
> +				char *next, const char *unused, void *arg)
>  {
>  	struct param_info *param_info = (struct param_info *)arg;
>  
> @@ -525,7 +522,7 @@ static int __init fadump_rework_cmdline_params(char *param, char *val,
>  		     strlen(FADUMP_EXTRA_ARGS_PARAM) - 1))
>  		return 0;
>  
> -	fadump_update_params(param_info, param, val);
> +	fadump_update_params(param_info, param, val, next);
>  
>  	return 0;
>  }
> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
> index e1bf5ca397fe..3a4cce552906 100644
> --- a/arch/powerpc/mm/hugetlbpage.c
> +++ b/arch/powerpc/mm/hugetlbpage.c
> @@ -268,8 +268,8 @@ int alloc_bootmem_huge_page(struct hstate *hstate)
>  
>  unsigned long gpage_npages[MMU_PAGE_COUNT];
>  
> -static int __init do_gpage_early_setup(char *param, char *val,
> -				       const char *unused, void *arg)
> +static int __init do_gpage_early_setup(char *param, char *val, char *unused1,
> +				       const char *unused2, void *arg)
>  {
>  	static phys_addr_t size;
>  	unsigned long npages;
> diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
> index 1ee7b30dafec..fec05a186c08 100644
> --- a/include/linux/moduleparam.h
> +++ b/include/linux/moduleparam.h
> @@ -326,7 +326,7 @@ extern char *parse_args(const char *name,
>  		      s16 level_min,
>  		      s16 level_max,
>  		      void *arg,
> -		      int (*unknown)(char *param, char *val,
> +		      int (*unknown)(char *param, char *val, char *next,
>  				     const char *doing, void *arg));
>  
>  /* Called by module remove. */
> diff --git a/init/main.c b/init/main.c
> index 052481fbe363..920c3564b2f0 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -239,7 +239,7 @@ static int __init loglevel(char *str)
>  early_param("loglevel", loglevel);
>  
>  /* Change NUL term back to "=", to make "param" the whole string. */
> -static int __init repair_env_string(char *param, char *val,
> +static int __init repair_env_string(char *param, char *val, char *unused2,
>  				    const char *unused, void *arg)
>  {
>  	if (val) {
> @@ -257,7 +257,7 @@ static int __init repair_env_string(char *param, char *val,
>  }
>  
>  /* Anything after -- gets handed straight to init. */
> -static int __init set_init_arg(char *param, char *val,
> +static int __init set_init_arg(char *param, char *val, char *unused2,
>  			       const char *unused, void *arg)
>  {
>  	unsigned int i;
> @@ -265,7 +265,7 @@ static int __init set_init_arg(char *param, char *val,
>  	if (panic_later)
>  		return 0;
>  
> -	repair_env_string(param, val, unused, NULL);
> +	repair_env_string(param, val, unused2, unused, NULL);
>  
>  	for (i = 0; argv_init[i]; i++) {
>  		if (i == MAX_INIT_ARGS) {
> @@ -282,10 +282,10 @@ static int __init set_init_arg(char *param, char *val,
>   * Unknown boot options get handed to init, unless they look like
>   * unused parameters (modprobe will find them in /proc/cmdline).
>   */
> -static int __init unknown_bootoption(char *param, char *val,
> +static int __init unknown_bootoption(char *param, char *val, char *unused2,
>  				     const char *unused, void *arg)
>  {
> -	repair_env_string(param, val, unused, NULL);
> +	repair_env_string(param, val, unused2, unused, NULL);
>  
>  	/* Handle obsolete-style parameters */
>  	if (obsolete_checksetup(param))
> @@ -437,7 +437,7 @@ static noinline void __ref rest_init(void)
>  }
>  
>  /* Check for early params. */
> -static int __init do_early_param(char *param, char *val,
> +static int __init do_early_param(char *param, char *val, char *unused2,
>  				 const char *unused, void *arg)
>  {
>  	const struct obs_kernel_param *p;
> diff --git a/kernel/module.c b/kernel/module.c
> index 40f983cbea81..5e241ba95a91 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -3609,8 +3609,8 @@ static int prepare_coming_module(struct module *mod)
>  	return 0;
>  }
>  
> -static int unknown_module_param_cb(char *param, char *val, const char *modname,
> -				   void *arg)
> +static int unknown_module_param_cb(char *param, char *val, char *next,
> +					const char *modname, void *arg)
>  {
>  	struct module *mod = arg;
>  	int ret;
> diff --git a/kernel/params.c b/kernel/params.c
> index 60b2d8101355..9f568fbf5287 100644
> --- a/kernel/params.c
> +++ b/kernel/params.c
> @@ -119,13 +119,14 @@ static void param_check_unsafe(const struct kernel_param *kp)
>  
>  static int parse_one(char *param,
>  		     char *val,
> +		     char *next,
>  		     const char *doing,
>  		     const struct kernel_param *params,
>  		     unsigned num_params,
>  		     s16 min_level,
>  		     s16 max_level,
>  		     void *arg,
> -		     int (*handle_unknown)(char *param, char *val,
> +		     int (*handle_unknown)(char *param, char *val, char *next,
>  				     const char *doing, void *arg))
>  {
>  	unsigned int i;
> @@ -153,7 +154,7 @@ static int parse_one(char *param,
>  
>  	if (handle_unknown) {
>  		pr_debug("doing %s: %s='%s'\n", doing, param, val);
> -		return handle_unknown(param, val, doing, arg);
> +		return handle_unknown(param, val, next, doing, arg);
>  	}
>  
>  	pr_debug("Unknown argument '%s'\n", param);
> @@ -168,10 +169,10 @@ char *parse_args(const char *doing,
>  		 s16 min_level,
>  		 s16 max_level,
>  		 void *arg,
> -		 int (*unknown)(char *param, char *val,
> +		 int (*unknown)(char *param, char *val, char *next,
>  				const char *doing, void *arg))
>  {
> -	char *param, *val, *err = NULL;
> +	char *param, *val, *next, *err = NULL;
>  
>  	/* Chew leading spaces */
>  	args = skip_spaces(args);
> @@ -179,16 +180,18 @@ char *parse_args(const char *doing,
>  	if (*args)
>  		pr_debug("doing %s, parsing ARGS: '%s'\n", doing, args);
>  
> -	while (*args) {
> +	next = next_arg(args, &param, &val);
> +	do {
>  		int ret;
>  		int irq_was_disabled;
>  
> -		args = next_arg(args, &param, &val);
> +		args = next;
> +		next = next_arg(args, &param, &val);
>  		/* Stop at -- */
>  		if (!val && strcmp(param, "--") == 0)
>  			return err ?: args;
>  		irq_was_disabled = irqs_disabled();
> -		ret = parse_one(param, val, doing, params, num,
> +		ret = parse_one(param, val, next, doing, params, num,
>  				min_level, max_level, arg, unknown);
>  		if (irq_was_disabled && !irqs_disabled())
>  			pr_warn("%s: option '%s' enabled irq's!\n",
> @@ -211,7 +214,7 @@ char *parse_args(const char *doing,
>  		}
>  
>  		err = ERR_PTR(ret);
> -	}
> +	} while (*next);
>  
>  	return err;
>  }
> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> index da796e2dc4f5..bdedc1ca5bf6 100644
> --- a/lib/dynamic_debug.c
> +++ b/lib/dynamic_debug.c
> @@ -888,7 +888,7 @@ static int ddebug_dyndbg_param_cb(char *param, char *val,
>  }
>  
>  /* handle both dyndbg and $module.dyndbg params at boot */
> -static int ddebug_dyndbg_boot_param_cb(char *param, char *val,
> +static int ddebug_dyndbg_boot_param_cb(char *param, char *val, char *unused2,
>  				const char *unused, void *arg)
>  {
>  	vpr_info("%s=\"%s\"\n", param, val);
> -- 
> 2.10.2