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Re: [Qemu-devel] [PATCH v4 1/5] qemu/compiler: Define QEMU_NONSTRING
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH v4 1/5] qemu/compiler: Define QEMU_NONSTRING |
Date: |
Sun, 30 Dec 2018 09:28:23 +1100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 |
On 12/29/18 4:33 AM, Philippe Mathieu-Daudé wrote:
> GCC 8 introduced the -Wstringop-truncation checker to detect truncation by
> the strncat and strncpy functions (closely related to -Wstringop-overflow,
> which detect buffer overflow by string-modifying functions declared in
> <string.h>).
>
> In tandem of -Wstringop-truncation, the "nonstring" attribute was added:
>
> The nonstring variable attribute specifies that an object or member
> declaration with type array of char, signed char, or unsigned char,
> or pointer to such a type is intended to store character arrays that
> do not necessarily contain a terminating NUL. This is useful in detecting
> uses of such arrays or pointers with functions that expect NUL-terminated
> strings, and to avoid warnings when such an array or pointer is used as
> an argument to a bounded string manipulation function such as strncpy.
>
> From the GCC manual:
> https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-nonstring-variable-attribute
>
> Add the QEMU_NONSTRING macro which checks if the compiler supports this
> attribute.
>
> Suggested-by: Michael S. Tsirkin <address@hidden>
> Reviewed-by: Eric Blake <address@hidden>
> Reviewed-by: Michael S. Tsirkin <address@hidden>
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> ---
Reviewed-by: Richard Henderson <address@hidden>
r~
- [Qemu-devel] [PATCH v4 0/5] Fix strncpy() warnings for GCC8 new -Wstringop-truncation, Philippe Mathieu-Daudé, 2018/12/28
- [Qemu-devel] [PATCH v4 5/5] migration: Use strnlen() for fixed-size string, Philippe Mathieu-Daudé, 2018/12/28
- [Qemu-devel] [PATCH v4 2/5] block/sheepdog: Use QEMU_NONSTRING for non NUL-terminated arrays, Philippe Mathieu-Daudé, 2018/12/28
- [Qemu-devel] [PATCH v4 1/5] qemu/compiler: Define QEMU_NONSTRING, Philippe Mathieu-Daudé, 2018/12/28
- Re: [Qemu-devel] [PATCH v4 1/5] qemu/compiler: Define QEMU_NONSTRING,
Richard Henderson <=
- [Qemu-devel] [PATCH v4 4/5] migration: Fix stringop-truncation warning, Philippe Mathieu-Daudé, 2018/12/28
- [Qemu-devel] [PATCH v4 3/5] hw/acpi: Use QEMU_NONSTRING for non NUL-terminated arrays, Philippe Mathieu-Daudé, 2018/12/28