GCC 8 added a -Wstringop-truncation warning:
The -Wstringop-truncation warning added in GCC 8.0 via r254630 for
bug 81117 is specifically intended to highlight likely unintended
uses of the strncpy function that truncate the terminating NUL
character from the source string.
Here the next line indeed unconditionally zeroes the last byte, but
1/ the buffer has been calloc'd, so we don't need to add an extra
byte, and 2/ we called vduse_name_is_invalid() which checked the
string length, so we can simply call strcpy().
This fixes when using gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0:
[42/666] Compiling C object subprojects/libvduse/libvduse.a.p/libvduse.c.o
FAILED: subprojects/libvduse/libvduse.a.p/libvduse.c.o
cc -m64 -mcx16 -Isubprojects/libvduse/libvduse.a.p -Isubprojects/libvduse -I../../subprojects/libvduse [...] -o subprojects/libvduse/libvduse.a.p/libvduse.c.o -c ../../subprojects/libvduse/libvduse.c
In file included from /usr/include/string.h:495,
from ../../subprojects/libvduse/libvduse.c:24:
In function ‘strncpy’,
inlined from ‘vduse_dev_create’ at ../../subprojects/libvduse/libvduse.c:1312:5:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ specified bound 256 equals destination size [-Werror=stringop-truncation]
106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
ninja: build stopped: cannot make progress due to previous errors.
Fixes: d9cf16c0be ("libvduse: Replace strcpy() with strncpy()")
Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Xie Yongji <xieyongji@bytedance.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Bin Meng <bmeng@tinylab.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20221111124550.35753-1-philmd@linaro.org>
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