[Bug middle-end/88780] [8/9/10 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[Bug middle-end/88780] [8/9/10 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[jiapei at longervision dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

Pei JIA <jiapei at longervision dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jiapei at longervision dot com

--- Comment #4 from Pei JIA <jiapei at longervision dot com> ---
gcc 9.3 in Ubuntu 20.04, this bug comes back????

[Bug middle-end/88780] [8/9/10/11 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[arjan.van.vught at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

Arjan van Vught <arjan.van.vught at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |arjan.van.vught at gmail dot com

--- Comment #5 from Arjan van Vught <arjan.van.vught at gmail dot com> ---
(In reply to Pei JIA from comment #4)
> gcc 9.3 in Ubuntu 20.04, this bug comes back????

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04 LTS
Release:        20.04
Codename:       focal

gcc --version
gcc (Ubuntu 9.3.0-10ubuntu2) 9.3.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

This code:
        strncpy(m_SourceName, pSourceName, E131_SOURCE_NAME_LENGTH - 1);
        m_SourceName[E131_SOURCE_NAME_LENGTH - 1] = '\0';

gives:

g++ -DNDEBUG -D_TIME_STAMP_YEAR_=2020 -D_TIME_STAMP_MONTH_=5
-D_TIME_STAMP_DAY_=26  -I./include -I../lib-hal/include -I../lib-debug/include
-I../lib-lightset/include -I../lib-properties/include -I../lib-hal/include
-I../lib-network/include -O2 -Wall -Werror -Wextra -Wpedantic -Wunused
-Wsign-conversion  -fno-rtti -fno-exceptions -fno-unwind-tables
-Wnon-virtual-dtor -Wuseless-cast -Wold-style-cast -std=c++11 -c
src/e131bridge.cpp -o build_linux/src/e131bridge.o
In file included from /usr/include/string.h:495,
                 from src/e131bridge.cpp:29:
In function ‘char* strncpy(char*, const char*, size_t)’,
    inlined from ‘void E131Bridge::SetSourceName(const char*)’ at
src/e131bridge.cpp:159:9,
    inlined from ‘E131Bridge::E131Bridge()’ at src/e131bridge.cpp:88:15,
    inlined from ‘E131Bridge::E131Bridge()’ at src/e131bridge.cpp:51:1:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:34: error: ‘char*
__builtin_strncpy(char*, const char*, long unsigned int)’ output may be
truncated copying 63 bytes from a string of length 63
[-Werror=stringop-truncation]
  106 |   return __builtin___strncpy_chk (__dest, __src, __len, __bos
(__dest));
      |          ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Workaround:

#if (__GNUC__ > 8)
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wstringop-truncation"
#endif
        strncpy(m_SourceName, pSourceName, E131_SOURCE_NAME_LENGTH - 1);
        m_SourceName[E131_SOURCE_NAME_LENGTH - 1] = '\0';
#if (__GNUC__ > 8)
# pragma GCC diagnostic pop
#endif

[Bug middle-end/88780] [8/9/10/11 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[marietto2008 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

Marietto <marietto2008 at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |marietto2008 at gmail dot com

--- Comment #6 from Marietto <marietto2008 at gmail dot com> ---
Hello.

I'm a xen user. I'm trying to Build Qemu & Xen for XenGT on Ubuntu 20.04
following this tutorial :

https://github.com/intel/gvt-linux/wiki/GVTg_Setup_Guide#332-build-qemu--xen-for-xengt

because I want to share the integrated GPU with a xen VM.

The main hardware components of my PC are the following :

CPU I9-9900k

Intel Corporation UHD Graphics 630 (Desktop 9 Series) (rev 02)

IVIDIA Corporation TU102 [GeForce RTX 2080 Ti] (rev a1)

The compilation gave no errors until this point :

root@ziomario-z390aoruspro:/etc/xen/igvtg-xen# make install-tools

......

make libs
make[5]: ingresso nella directory «/etc/xen/igvtg-xen/tools/libxc»
rm -f _paths.h.tmp; echo "#define sbindir "/usr/sbin"" >>_paths.h.tmp; echo
"#define bindir "/usr/bin"" >>_paths.h.tmp; echo "#define LIBEXEC
"/usr/lib/xen"" >>_paths.h.tmp; echo "#define LIBEXEC_BIN "/usr/lib/xen/bin""
>>_paths.h.tmp; echo "#define libdir "/usr/lib"" >>_paths.h.tmp; echo "#define
SHAREDIR "/usr/share"" >>_paths.h.tmp; echo "#define XENFIRMWAREDIR
"/usr/lib/xen/boot"" >>_paths.h.tmp; echo "#define XEN_CONFIG_DIR "/etc/xen""
>>_paths.h.tmp; echo "#define XEN_SCRIPT_DIR "/etc/xen/scripts""
>>_paths.h.tmp; echo "#define XEN_LOCK_DIR "/var/lock"" >>_paths.h.tmp; echo
"#define XEN_RUN_DIR "/var/run/xen"" >>_paths.h.tmp; echo "#define
XEN_PAGING_DIR "/var/lib/xen/xenpaging"" >>_paths.h.tmp; echo "#define
XEN_DUMP_DIR "/var/lib/xen/dump"" >>_paths.h.tmp; echo "#define XEN_LOG_DIR
"/var/log/xen"" >>_paths.h.tmp; echo "#define XEN_LIB_DIR "/var/lib/xen""
>>_paths.h.tmp; echo "#define XEN_RUN_STORED "/var/run/xenstored""
>>_paths.h.tmp; if ! cmp -s _paths.h.tmp paths.h; then mv -f paths.h.tmp
paths.h; else rm -f paths.h.tmp; fi
gcc -m64 -DBUILD_ID -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes
-Wdeclaration-after-statement -Wno-unused-but-set-variable
-Wno-unused-local-typedefs -O2 -fomit-frame-pointer
-D__XEN_INTERFACE_VERSION=XEN_LATEST_INTERFACE_VERSION -MMD -MF .xc_pm.o.d
-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_GNU_SOURCE
-I../../xen/common/libelf -Werror -Wmissing-prototypes -I. -I./include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/include -D__XEN_TOOLS -pthread
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/libs/toollog/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/libs/evtchn/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/libs/devicemodel/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/include -include
/etc/xen/igvtg-xen/tools/libxc/../../tools/config.h
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/libs/call/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/libs/foreignmemory/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/libs/gnttab/include
-I/etc/xen/igvtg-xen/tools/libxc/../../tools/include -c -o xc_pm.o xc_pm.c
In file included from /usr/include/string.h:495,
from xc_private.h:24,
from xc_pm.c:22:
In function ‘strncpy’,
inlined from ‘xc_set_cpufreq_gov’ at xc_pm.c:308:5:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error:
‘__builtin_strncpy’ specified bound 16 equals destination size
[-Werror=stringop-truncation]
106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
make[5]: *** [/etc/xen/igvtg-xen/tools/libxc/../../tools/Rules.mk:222: xc_pm.o]
Errore 1
make[5]: uscita dalla directory «/etc/xen/igvtg-xen/tools/libxc»
make[4]: *** [Makefile:184: build] Errore 2
make[4]: uscita dalla directory «/etc/xen/igvtg-xen/tools/libxc»
make[3]: *** [/etc/xen/igvtg-xen/tools/../tools/Rules.mk:246:
subdir-install-libxc] Errore 2
make[3]: uscita dalla directory «/etc/xen/igvtg-xen/tools»
make[2]: *** [/etc/xen/igvtg-xen/tools/../tools/Rules.mk:241: subdirs-install]
Errore 2
make[2]: uscita dalla directory «/etc/xen/igvtg-xen/tools»
make[1]: *** [Makefile:74: install] Errore 2
make[1]: uscita dalla directory «/etc/xen/igvtg-xen/tools»
make: *** [Makefile:127: install-tools] Errore 2

how can I fix it ?

[Bug middle-end/88780] [8/9/10/11 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

--- Comment #7 from Martin Sebor <msebor at gcc dot gnu.org> ---
(In reply to Marietto from comment #6)
...
> In function ‘strncpy’,
> inlined from ‘xc_set_cpufreq_gov’ at xc_pm.c:308:5:
> /usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error:
> ‘__builtin_strncpy’ specified bound 16 equals destination size
> [-Werror=stringop-truncation]
> 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This instance of the warning is most likely unrelated to the one reported in
comment #0 (to tell for sure we'd need a test case to reproduce it).  It
indicates that strncpy is being called with the third argument set to the size
of the destination array, which leaves the destination unterminated unless the
source string is shorter.  The following articles describe the problem and the
suggested solutions in detail:

https://developers.redhat.com/blog/2018/05/24/detecting-string-truncation-with-gcc-8/
https://us-cert.cisa.gov/bsi/articles/knowledge/coding-practices/strncpy-and-strncat

[Bug middle-end/88780] [8/9/10/11 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[marietto2008 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

--- Comment #8 from Marietto <marietto2008 at gmail dot com> ---
https://bugs.launchpad.net/ubuntu/+source/gcc-9/+bug/1892475

Il giorno mar 18 ago 2020 alle ore 19:26 msebor at gcc dot gnu.org <
gcc-bugzilla@gcc.gnu.org> ha scritto:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780
>
> --- Comment #7 from Martin Sebor <msebor at gcc dot gnu.org> ---
> (In reply to Marietto from comment #6)
> ...
> > In function ‘strncpy’,
> > inlined from ‘xc_set_cpufreq_gov’ at xc_pm.c:308:5:
> > /usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error:
> > ‘__builtin_strncpy’ specified bound 16 equals destination size
> > [-Werror=stringop-truncation]
> > 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos
> (__dest));
> > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> This instance of the warning is most likely unrelated to the one reported
> in
> comment #0 (to tell for sure we'd need a test case to reproduce it).  It
> indicates that strncpy is being called with the third argument set to the
> size
> of the destination array, which leaves the destination unterminated unless
> the
> source string is shorter.  The following articles describe the problem and
> the
> suggested solutions in detail:
>
>
> https://developers.redhat.com/blog/2018/05/24/detecting-string-truncation-with-gcc-8/
>
> https://us-cert.cisa.gov/bsi/articles/knowledge/coding-practices/strncpy-and-strncat
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.

[Bug middle-end/88780] [9/10/11/12 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|8.5                         |9.4

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 8 branch is being closed.

[Bug middle-end/88780] [9/10/11/12 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|9.4                         |9.5

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 9.4 is being released, retargeting bugs to GCC 9.5.

[Bug middle-end/88780] [9/10/11/12 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|msebor at gcc dot gnu.org          |unassigned at gcc dot gnu.org
             Status|ASSIGNED                    |NEW

--- Comment #11 from Martin Sebor <msebor at gcc dot gnu.org> ---
I'm no longer working on this.

[Bug middle-end/88780] [10/11/12/13 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|9.5                         |10.4

--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 9 branch is being closed

[Bug middle-end/88780] [10/11/12/13 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.4                        |10.5

--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 10.4 is being released, retargeting bugs to GCC 10.5.

[Bug middle-end/88780] [11/12/13/14 Regression] bogus -Wstringop-truncation for copying as many bytes from a string as its length

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88780

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.5                        |11.5

--- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10 branch is being closed.