1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Helper function for splitting a string into an argv-like array.
  4 */
  5
  6#include <stdlib.h>
  7#include <linux/kernel.h>
  8#include <linux/ctype.h>
  9#include <linux/string.h>
 10
 11static const char *skip_arg(const char *cp)
 12{
 13	while (*cp && !isspace(*cp))
 14		cp++;
 15
 16	return cp;
 17}
 18
 19static int count_argc(const char *str)
 20{
 21	int count = 0;
 22
 23	while (*str) {
 24		str = skip_spaces(str);
 25		if (*str) {
 26			count++;
 27			str = skip_arg(str);
 28		}
 29	}
 30
 31	return count;
 32}
 33
 34/**
 35 * argv_free - free an argv
 36 * @argv - the argument vector to be freed
 37 *
 38 * Frees an argv and the strings it points to.
 39 */
 40void argv_free(char **argv)
 41{
 42	char **p;
 43	for (p = argv; *p; p++) {
 44		free(*p);
 45		*p = NULL;
 46	}
 47
 48	free(argv);
 49}
 50
 51/**
 52 * argv_split - split a string at whitespace, returning an argv
 53 * @str: the string to be split
 54 * @argcp: returned argument count
 55 *
 56 * Returns an array of pointers to strings which are split out from
 57 * @str.  This is performed by strictly splitting on white-space; no
 58 * quote processing is performed.  Multiple whitespace characters are
 59 * considered to be a single argument separator.  The returned array
 60 * is always NULL-terminated.  Returns NULL on memory allocation
 61 * failure.
 62 */
 63char **argv_split(const char *str, int *argcp)
 64{
 65	int argc = count_argc(str);
 66	char **argv = calloc(argc + 1, sizeof(*argv));
 67	char **argvp;
 68
 69	if (argv == NULL)
 70		goto out;
 71
 72	if (argcp)
 73		*argcp = argc;
 74
 75	argvp = argv;
 76
 77	while (*str) {
 78		str = skip_spaces(str);
 79
 80		if (*str) {
 81			const char *p = str;
 82			char *t;
 83
 84			str = skip_arg(str);
 85
 86			t = strndup(p, str-p);
 87			if (t == NULL)
 88				goto fail;
 89			*argvp++ = t;
 90		}
 91	}
 92	*argvp = NULL;
 93
 94out:
 95	return argv;
 96
 97fail:
 98	argv_free(argv);
 99	return NULL;
100}