// SPDX-License-Identifier: GPL-2.0
/*
 * Helper function for splitting a string into an argv-like array.
 */

#include <stdlib.h>
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <linux/string.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++) {
                free(*p);
                *p = NULL;
        }

        free(argv);
}

/**
 * argv_split - split a string at whitespace, returning an argv
 * @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(const char *str, int *argcp)
{
        int argc = count_argc(str);
        char **argv = calloc(argc + 1, sizeof(*argv));
        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 = strndup(p, str-p);
                        if (t == NULL)
                                goto fail;
                        *argvp++ = t;
                }
        }
        *argvp = NULL;

out:
        return argv;

fail:
        argv_free(argv);
        return NULL;
}