Re: [PATCH] Implement kasprintf

["Randy.Dunlap" <rdunlap@xenotime.net>]

On Tue, 20 Jun 2006 16:57:16 -0700 Jeremy Fitzhardinge wrote:

> From: Jeremy Fitzhardinge <jeremy@xensource.com>
> 
> Implement kasprintf, a kernel version of asprintf.  This allocates the
> memory required for the formatted string, including the trailing '\0'.
> Returns NULL on allocation failure.
> 
> Requires vsnprintf to accept a NULL buffer when the buffer size is 0.
> 
> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
> 
> ---
>  include/linux/kernel.h |    2 +
>  lib/Makefile           |    2 -
>  lib/kasprintf.c        |   54 ++++++++++++++++++++++++++++++++++++++++++++++++

Hi,
<nit>

Why do we want a separate source file for this one function?


>  3 files changed, 57 insertions(+), 1 deletion(-)
> 
> 
> diff -r c175fd50e604 include/linux/kernel.h
> --- a/include/linux/kernel.h	Tue Jun 20 16:47:53 2006 -0700
> +++ b/include/linux/kernel.h	Tue Jun 20 16:53:19 2006 -0700
> @@ -114,6 +114,8 @@ extern int scnprintf(char * buf, size_t 
>  	__attribute__ ((format (printf, 3, 4)));
>  extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args)
>  	__attribute__ ((format (printf, 3, 0)));
> +extern char *kasprintf(gfp_t gfp, const char *fmt, ...)
> +	__attribute__ ((format (printf, 2, 3)));
>  
>  extern int sscanf(const char *, const char *, ...)
>  	__attribute__ ((format (scanf, 2, 3)));
> diff -r c175fd50e604 lib/Makefile
> --- a/lib/Makefile	Tue Jun 20 16:47:53 2006 -0700
> +++ b/lib/Makefile	Tue Jun 20 16:53:19 2006 -0700
> @@ -5,7 +5,7 @@ lib-y := errno.o ctype.o string.o vsprin
>  lib-y := errno.o ctype.o string.o vsprintf.o cmdline.o \
>  	 bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \
>  	 idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
> -	 sha1.o
> +	 sha1.o kasprintf.o
>  
>  lib-$(CONFIG_SMP) += cpumask.o
>  
> diff -r c175fd50e604 lib/kasprintf.c
> --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
> +++ b/lib/kasprintf.c	Tue Jun 20 16:53:19 2006 -0700
> @@ -0,0 +1,54 @@
> +/******************************************************************************
> + * Simplified asprintf.
> + *
> + * Copyright (C) 2006 XenSource Ltd
> + * 
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License version 2
> + * as published by the Free Software Foundation; or, when distributed
> + * separately from the Linux kernel or incorporated into other
> + * software packages, subject to the following license:
> + * 
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this source file (the "Software"), to deal in the Software without
> + * restriction, including without limitation the rights to use, copy, modify,
> + * merge, publish, distribute, sublicense, and/or sell copies of the Software,
> + * and to permit persons to whom the Software is furnished to do so, subject to
> + * the following conditions:
> + * 
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + * 
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +
> +/* Simplified asprintf. */
> +char *kasprintf(gfp_t gfp, const char *fmt, ...)
> +{
> +	va_list ap;
> +	unsigned int len;
> +	char *p;
> +
> +	va_start(ap, fmt);
> +	len = vsnprintf(NULL, 0, fmt, ap);
> +	va_end(ap);
> +
> +	p = kmalloc(len+1, gfp);
> +	if (!p)
> +		return NULL;
> +	va_start(ap, fmt);
> +	vsnprintf(p, len+1, fmt, ap);
> +	va_end(ap);
> +	return p;
> +}
> +EXPORT_SYMBOL(kasprintf);

---
~Randy