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/* * Helper function for splitting a string into an argv-like array. */ #include <linux/kernel.h>#include <linux/ctype.h>#include <linux/string.h>#include <linux/slab.h>#include <linux/module.h> static const char *skip_arg(const char *cp){	while (*cp && !isspace(*cp))		cp++; 	return cp;} static int count_argc(const char *str){	int count = 0; 	while (*str) {		str = skip_spaces(str);		if (*str) {			count++;			str = skip_arg(str);		}	} 	return count;} /** * argv_free - free an argv * @argv - the argument vector to be freed * * Frees an argv and the strings it points to. */void argv_free(char **argv){	char **p;	for (p = argv; *p; p++)		kfree(*p); 	kfree(argv);}EXPORT_SYMBOL(argv_free); /** * argv_split - split a string at whitespace, returning an argv * @gfp: the GFP mask used to allocate memory * @str: the string to be split * @argcp: returned argument count * * Returns an array of pointers to strings which are split out from * @str.  This is performed by strictly splitting on white-space; no * quote processing is performed.  Multiple whitespace characters are * considered to be a single argument separator.  The returned array * is always NULL-terminated.  Returns NULL on memory allocation * failure. */char **argv_split(gfp_t gfp, const char *str, int *argcp){	int argc = count_argc(str);	char **argv = kzalloc(sizeof(*argv) * (argc+1), gfp);	char **argvp; 	if (argv == NULL)		goto out; 	if (argcp)		*argcp = argc; 	argvp = argv; 	while (*str) {		str = skip_spaces(str); 		if (*str) {			const char *p = str;			char *t; 			str = skip_arg(str); 			t = kstrndup(p, str-p, gfp);			if (t == NULL)				goto fail;			*argvp++ = t;		}	}	*argvp = NULL;   out:	return argv;   fail:	argv_free(argv);	return NULL;}EXPORT_SYMBOL(argv_split);