argv_split.c

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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/export.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;
}

void argv_free(char **argv)
{
    char **p;
    for (p = argv; *p; p++)
        kfree(*p);

    kfree(argv);
}
EXPORT_SYMBOL(argv_free);

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);