/* *  linux/lib/kasprintf.c * *  Copyright (C) 1991, 1992  Linus Torvalds */ #include <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);