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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Kent Gibson <warthog618@gmail.com>,
	linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH 03/23] lib: uaccess: provide getline_from_user()
Date: Fri, 4 Sep 2020 19:35:17 +0300	[thread overview]
Message-ID: <20200904163517.GW1891694@smile.fi.intel.com> (raw)
In-Reply-To: <20200904154547.3836-4-brgl@bgdev.pl>

On Fri, Sep 04, 2020 at 05:45:27PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> Provide a uaccess helper that allows callers to copy a single line from
> user memory. This is useful for debugfs write callbacks.

Doesn't mm/util.c provides us something like this?
strndup_user()?

> 
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  include/linux/uaccess.h |  3 +++
>  lib/usercopy.c          | 37 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
> index 94b285411659..5aedd8ac5c31 100644
> --- a/include/linux/uaccess.h
> +++ b/include/linux/uaccess.h
> @@ -333,6 +333,9 @@ long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
>  		long count);
>  long strnlen_user_nofault(const void __user *unsafe_addr, long count);
>  
> +ssize_t getline_from_user(char *dst, size_t dst_size,
> +			  const char __user *src, size_t src_size);
> +
>  /**
>   * get_kernel_nofault(): safely attempt to read from a location
>   * @val: read into this variable
> diff --git a/lib/usercopy.c b/lib/usercopy.c
> index b26509f112f9..55aaaf93d847 100644
> --- a/lib/usercopy.c
> +++ b/lib/usercopy.c
> @@ -87,3 +87,40 @@ int check_zeroed_user(const void __user *from, size_t size)
>  	return -EFAULT;
>  }
>  EXPORT_SYMBOL(check_zeroed_user);
> +
> +/**
> + * getline_from_user - Copy a single line from user
> + * @dst: Where to copy the line to
> + * @dst_size: Size of the destination buffer
> + * @src: Where to copy the line from
> + * @src_size: Size of the source user buffer
> + *
> + * Copies a number of characters from given user buffer into the dst buffer.
> + * The number of bytes is limited to the lesser of the sizes of both buffers.
> + * If the copied string contains a newline, its first occurrence is replaced
> + * by a NULL byte in the destination buffer. Otherwise the function ensures
> + * the copied string is NULL-terminated.
> + *
> + * Returns the number of copied bytes or a negative error number on failure.
> + */
> +
> +ssize_t getline_from_user(char *dst, size_t dst_size,
> +			  const char __user *src, size_t src_size)
> +{
> +	size_t size = min_t(size_t, dst_size, src_size);
> +	char *c;
> +	int ret;
> +
> +	ret = copy_from_user(dst, src, size);
> +	if (ret)
> +		return -EFAULT;
> +
> +	dst[size - 1] = '\0';
> +
> +	c = strchrnul(dst, '\n');
> +	if (*c)
> +		*c = '\0';
> +
> +	return c - dst;
> +}
> +EXPORT_SYMBOL(getline_from_user);
> -- 
> 2.26.1
> 

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2020-09-04 16:35 UTC|newest]

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-04 15:45 [PATCH 00/23] gpio: mockup: support dynamically created and removed chips Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 01/23] lib: cmdline: export next_arg() Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 02/23] lib: string_helpers: provide kfree_strarray() Bartosz Golaszewski
2020-09-04 16:33   ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 03/23] lib: uaccess: provide getline_from_user() Bartosz Golaszewski
2020-09-04 16:35   ` Andy Shevchenko [this message]
2020-09-07 10:02     ` Bartosz Golaszewski
2020-09-07 10:18       ` Andy Shevchenko
2020-09-07 10:28         ` Bartosz Golaszewski
2020-09-07 11:45           ` Andy Shevchenko
2020-09-07 11:57             ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 04/23] gpiolib: generalize devprop_gpiochip_set_names() for device properties Bartosz Golaszewski
2020-09-04 16:38   ` Andy Shevchenko
2020-09-07 10:56     ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 05/23] gpiolib: unexport devprop_gpiochip_set_names() Bartosz Golaszewski
2020-09-04 16:40   ` Andy Shevchenko
2020-09-07 10:53     ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 06/23] gpiolib: switch to simpler IDA interface Bartosz Golaszewski
2020-09-04 16:41   ` Andy Shevchenko
2020-09-07 10:50     ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 07/23] gpio: mockup: drop unneeded includes Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 08/23] gpio: mockup: use pr_fmt() Bartosz Golaszewski
2020-09-04 16:29   ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 09/23] gpio: mockup: use KBUILD_MODNAME Bartosz Golaszewski
2020-09-04 16:30   ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 10/23] gpio: mockup: fix resource leak in error path Bartosz Golaszewski
2020-09-04 17:00   ` Andy Shevchenko
2020-09-07 11:04     ` Bartosz Golaszewski
2020-09-07 11:47       ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 11/23] gpio: mockup: remove the limit on number of dummy chips Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 12/23] gpio: mockup: define a constant for chip label size Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 13/23] gpio: mockup: pass the chip label as device property Bartosz Golaszewski
2020-09-04 16:48   ` Andy Shevchenko
2020-09-07 11:01     ` Bartosz Golaszewski
2020-09-07 11:48       ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 14/23] gpio: mockup: use the generic 'gpio-line-names' property Bartosz Golaszewski
2020-09-04 16:46   ` Andy Shevchenko
2020-09-07 10:58     ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 15/23] gpio: mockup: use dynamic device IDs Bartosz Golaszewski
2020-09-04 16:49   ` Andy Shevchenko
2020-09-07 11:04     ` Bartosz Golaszewski
2020-09-07 11:50       ` Andy Shevchenko
2020-09-07 11:59         ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 16/23] gpio: mockup: refactor the module init function Bartosz Golaszewski
2020-09-04 16:50   ` Andy Shevchenko
2020-09-07 11:05     ` Bartosz Golaszewski
2020-09-07 11:51       ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 17/23] gpio: mockup: rename and move around debugfs callbacks Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 18/23] gpio: mockup: require debugfs to build Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 19/23] gpio: mockup: add a symlink for the per-chip debugfs directory Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 20/23] gpio: mockup: add a lock for dummy device list Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 21/23] gpio: mockup: provide a way to delete dummy chips Bartosz Golaszewski
2020-09-04 16:56   ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 22/23] gpio: mockup: provide a way to create new " Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 23/23] Documentation: gpio: add documentation for gpio-mockup Bartosz Golaszewski
2020-09-04 16:58   ` Andy Shevchenko
2020-09-05  3:15   ` Randy Dunlap
2020-09-07  9:59     ` Andy Shevchenko
2020-09-07 10:26       ` Bartosz Golaszewski
2020-09-07 11:53         ` Andy Shevchenko
2020-09-07 12:06           ` Bartosz Golaszewski
2020-09-07 12:22             ` Greg Kroah-Hartman
2020-09-07 13:49               ` Bartosz Golaszewski
2020-09-07 14:08                 ` Andy Shevchenko
2020-09-07 15:14                   ` Bartosz Golaszewski
2020-09-07 15:23                   ` Geert Uytterhoeven
2020-09-07 16:08                     ` Bartosz Golaszewski
2020-09-08 17:03               ` Bartosz Golaszewski
2020-09-11 12:56                 ` Greg Kroah-Hartman
2020-09-11 13:07                   ` Bartosz Golaszewski
2020-09-07 12:38             ` Andy Shevchenko
2020-09-07 12:57               ` Bartosz Golaszewski
2020-09-07 13:52                 ` Andy Shevchenko
2020-09-07 10:45     ` Bartosz Golaszewski

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