// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/lib/kasprintf.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/stdarg.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/string.h>

/* Simplified asprintf. */
char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap)
{
        unsigned int first, second;
        char *p;
        va_list aq;

        va_copy(aq, ap);
        first = vsnprintf(NULL, 0, fmt, aq);
        va_end(aq);

        p = kmalloc_track_caller(first+1, gfp);
        if (!p)
                return NULL;

        second = vsnprintf(p, first+1, fmt, ap);
        WARN(first != second, "different return values (%u and %u) from vsnprintf(\"%s\", ...)",
             first, second, fmt);

        return p;
}
EXPORT_SYMBOL(kvasprintf);

/*
 * If fmt contains no % (or is exactly %s), use kstrdup_const. If fmt
 * (or the sole vararg) points to rodata, we will then save a memory
 * allocation and string copy. In any case, the return value should be
 * freed using kfree_const().
 */
const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list ap)
{
        if (!strchr(fmt, '%'))
                return kstrdup_const(fmt, gfp);
        if (!strcmp(fmt, "%s"))
                return kstrdup_const(va_arg(ap, const char*), gfp);
        return kvasprintf(gfp, fmt, ap);
}
EXPORT_SYMBOL(kvasprintf_const);

char *kasprintf(gfp_t gfp, const char *fmt, ...)
{
        va_list ap;
        char *p;

        va_start(ap, fmt);
        p = kvasprintf(gfp, fmt, ap);
        va_end(ap);

        return p;
}
EXPORT_SYMBOL(kasprintf);