Bug 394565 - In Vt102Emulation snprintf truncation warnings while compiling
Summary: In Vt102Emulation snprintf truncation warnings while compiling
Status: RESOLVED FIXED
Alias: None
Product: konsole
Classification: Applications
Component: general (show other bugs)
Version: master
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Konsole Developer
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2018-05-22 13:06 UTC by Ahmad Samir
Modified: 2018-05-23 23:42 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


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Description Ahmad Samir 2018-05-22 13:06:05 UTC
Possibly related to this change[1]; I got this compiling current git master:
/home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.cpp: In member function 'void Konsole::Vt102Emulation::reportCursorPosition()':
/home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.cpp:955:30: warning: '%d' directive output may be truncated writing between 1 and 11 bytes into a region of size between 6 and 16 [-Wformat-truncation=]
   snprintf(tmp, sizeof(tmp), "\033[%d;%dR", _currentScreen->getCursorY()+1, _currentScreen->getCursorX()+1);
                              ^~~~~~~~~~~~~
/home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.cpp:955:30: note: directive argument in the range [-2147483647, 2147483647]
In file included from /usr/include/stdio.h:862,
                 from /usr/include/c++/8/cstdio:42,
                 from /usr/include/c++/8/ext/string_conversions.h:43,
                 from /usr/include/c++/8/bits/basic_string.h:6361,
                 from /usr/include/c++/8/string:52,
                 from /usr/include/qt5/QtCore/qbytearray.h:52,
                 from /usr/include/qt5/QtCore/qstring.h:49,
                 from /usr/include/qt5/QtCore/qhashfunctions.h:44,
                 from /usr/include/qt5/QtCore/qlist.h:47,
                 from /usr/include/qt5/QtCore/qhash.h:46,
                 from /usr/include/qt5/QtCore/QHash:1,
                 from /home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.h:27,
                 from /home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.cpp:24:
/usr/include/bits/stdio2.h:64:35: note: '__builtin___snprintf_chk' output between 7 and 27 bytes into a destination of size 20
   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        __bos (__s), __fmt, __va_arg_pack ());
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.cpp: In member function 'virtual void Konsole::Vt102Emulation::sendMouseEvent(int, int, int, int)':
/home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.cpp:1057:44: warning: '%d' directive output may be truncated writing between 1 and 10 bytes into a region of size between 7 and 26 [-Wformat-truncation=]
         snprintf(command, sizeof(command), "\033[%d;%d;%dM", cb + 0x20, cx, cy);
                                            ^~~~~~~~~~~~~~~~
/home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.cpp:1057:44: note: directive argument in the range [1, 2147483647]
In file included from /usr/include/stdio.h:862,
                 from /usr/include/c++/8/cstdio:42,
                 from /usr/include/c++/8/ext/string_conversions.h:43,
                 from /usr/include/c++/8/bits/basic_string.h:6361,
                 from /usr/include/c++/8/string:52,
                 from /usr/include/qt5/QtCore/qbytearray.h:52,
                 from /usr/include/qt5/QtCore/qstring.h:49,
                 from /usr/include/qt5/QtCore/qhashfunctions.h:44,
                 from /usr/include/qt5/QtCore/qlist.h:47,
                 from /usr/include/qt5/QtCore/qhash.h:46,
                 from /usr/include/qt5/QtCore/QHash:1,
                 from /home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.h:27,
                 from /home/builder/rpmbuild/konsole5/konsole5-f27/BUILD/konsole-18.07.70/src/Vt102Emulation.cpp:24:
/usr/include/bits/stdio2.h:64:35: note: '__builtin___snprintf_chk' output between 9 and 37 bytes into a destination of size 32
   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
          ~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        __bos (__s), __fmt, __va_arg_pack ());
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[1]
Comment 1 Mariusz Glebocki 2018-05-22 16:18:05 UTC
Looking at the code this warning should always be there (first build with gcc 8?). It is also irrevelant, unless someone uses 8-digit-long terminal width/height. Increasing the buffer size to 27 will solve the problem.

I'll fix this
Comment 2 Ahmad Samir 2018-05-22 16:32:41 UTC
(In reply to Mariusz Glebocki from comment #1)
> Looking at the code this warning should always be there (first build with
> gcc 8?).

First time I see that warning, could have been there before

> It is also irrevelant, unless someone uses 8-digit-long terminal
> width/height. 

OK, good to know; I wasn't sure if it were important or not so I filed a bug to track the issue / get it looked at.

[...]

Regards.
Comment 3 Kurt Hindenburg 2018-05-23 23:42:36 UTC
Git commit 847b72358d6c5371e7c8119c7081139112ced728 by Kurt Hindenburg, on behalf of Mariusz Glebocki.
Committed on 23/05/2018 at 23:42.
Pushed by hindenburg into branch 'master'.

Silence -Wformat-truncation warnings

Summary:
Add a few bytes to a small arrays on stack in order to make compiler
happy. Those warnings are invalid in this context (as long as terminal
width and height are not larger than 8-digits-long number).

Test Plan:
* Build Konsole with GCC 8 and `-Wformat-truncation` flag

Expected result: no format-truncation warnings
Actual result: three format-truncation warnings appear

Reviewers: #konsole, hindenburg

Reviewed By: #konsole, hindenburg

Subscribers: hindenburg, konsole-devel, #konsole

Tags: #konsole

Differential Revision: https://phabricator.kde.org/D13080

M  +2    -2    src/Vt102Emulation.cpp

https://commits.kde.org/konsole/847b72358d6c5371e7c8119c7081139112ced728