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Latest revision as of 18:42, 27 February 2012

build errors

No X display available

Some packages require the availability of an X display during the package build. If no interaction is needed, this can be solved with Xvfb: just add

BuildRequires: x11-server-xvfb

and run the command with xvfb-run, e.g.

xvfb-run make check

undefined reference to `xxx'

In ROSA Linux, packages are built with ld flag --no-undefined to prevent underlinking shared libraries.

gcc -shared foo.o -ldl /usr/lib/libglib-2.0.so /usr/lib/libXext.so ... -Wl,--no-undefined -o .libs/libkeymouselistener.so
.libs/keymouselistener.o: In function `parse_line':
.../gdm-2.20.6/gui/modules/keymouselistener.c:410: undefined reference to `XKeysymToKeycode'
collect2: ld returned 1 exit status

Check underlinking to understand how to fix.

Missing %files for subpackage foo

Subpackage foo with no %files foo raises a fatal error. It helps to detect dead subpackages, or typos in .spec file.

It also occurs in valid spec files, when "%files foo" appears inside a %if %ccc ... %endif. The fix is to put the whole %package foo section inside a %if %ccc ... %endif.

format not a string literal and no format arguments

In modern gcc, things like printf(error_message) instead of printf("%s", error_message) are detected by -Werror=format-security which is used by default. The reason for this error is described on the following Wikipedia page: format string attack

Example of error:

fud.c:72: error: format not a string literal and no format arguments

simple fixes

The fix can be something like:

-      printf(xkblayouttext);
+      printf("%s", xkblayouttext);

-      syslog(LOG_ERR, error_message(r));
+      syslog(LOG_ERR, "%s", error_message(r));

-   snprintf(id_resp_command, MAXIDVALUELEN, *argv);
+   snprintf(id_resp_command, MAXIDVALUELEN, "%s", *argv);

(another example: nautilus fix)

C++ code

Beware of C++ objects:

  QCString msgText = substitute(outputFormat, "$file", fileSubst) + '\n';
  fprintf(warnFile, msgText);

simply doing fprintf(warnFile, "%s", msgText) would introduce a crash, as warned by gcc:

message.cpp:150: warning: cannot pass objects of non-POD type 'class QCString' through '...'; call will abort at runtime
message.cpp:150: warning: format '%s' expects type 'char*', but argument 3 has type 'int'

You must explicitly cast to (const char *):

fprintf(warnFile, "%s", (const char *) msgText);

or simpler:

fputs(msgText, warnFile);

code doing % escaping by hand

Beware of weird code like (from doxygen):

  QCString msgText = substitute(substitute(outputFormat, "$file", fileSubst),
                                "%", "%%") + '\n';
  fprintf(warnFile, msgText);

Doing fputs(msgText, warnFile) modifies the program's behaviour since % will be displayed %% since % is escaped in msgText. The correct fix is to also get rid of the %s escaping:

  QCString msgText = substitute(outputFormat, "$file", fileSubst) + '\n';
  fputs(msgText, warnFile);

but you can also disable the warning (see below) and keep the code unchanged, since the code is valid (even if ugly).

disabling this warning

If the code is valid, you can disable the check using %define Werror_cflags %nil

The use of -Werror=format-security is inpired by Debian Hardening and Ubuntu CompilerFlags which use -Wformat-security to detect such issues.

Autotools problems

If you experience problems with autotools stuff, you should first ensure that you follow the Autotools recommendations in your spec files.

libtool version mismatch

If you get the error like

libtool: You should recreate aclocal.m4 with macros from libtool x.y.z

you should regenerate files created by autotools and shipped with upstream sources (see Autotools recommendations for details).

error: possibly undefined macro: AM_ACLOCAL_INCLUDE

Fix is to replace AM_ACLOCAL_INCLUDE call in configure.in or configure.ac with ACLOCAL_AMFLAGS variable in Makefile.am. For example, if configure.in has AM_ACLOCAL_INCLUDE(macros), remove it and add this to Makefile.am:

ACLOCAL_AMFLAGS = -I macros

conflicting types for `getline'

A file includes /usr/include/stdio.h but at the same time defines a local getline function. Fix is to rename the local getline, e.g. 'parseline'. You may do this automatically with this command:

perl -pi -e 's|getline|parseline|' path/to/src/*.c

build warnings

overlinking

To reduce overlinking, rpm can display some warnings alike:

Warning: unused libraries in /usr/bin/xdm: /usr/lib/libXext.so.6 /usr/lib/libXt.so.6 /usr/lib/libSM.so.6 /usr/lib/libXpm.so.4 /usr/lib/libxcb-xlib.so.0 /usr/lib/libxcb.so.1

Check overlinking to understand how to fix.

underlinking

To reduce underlinking, rpm can display some warnings alike:

Warning: undefined symbols in /usr/lib/libgmodule-1.2.so.0.0.10: g_free g_thread_functions_for_glib_use g_threads_got_initialized ...

Check underlinking to understand how to fix.

rpm loop warnings

LOOP warnings from tsort relations

Example:
warning: LOOP:
warning: removing libdrakx-net-0.94-1.1.noarch "Requires: /usr/share/locale/fr/LC_MESSAGES" from tsort relations.
warning: removing harddrake-13.52-1.i586 "Requires: drakxtools-curses = 13.52-1" from tsort relations.
warning: removing drakxtools-curses-13.52-1.i586 "Requires(hint): drakx-net-text" from tsort relations.
warning: removing drakx-net-text-0.94-1.1.noarch "Requires: libdrakx-net = 0.94" from tsort relations.

• What is a Tsort relation?

The set of ordered dependencies, before rpm installation, so if rpm installation order is not correct, this may result in broken installations, it is important to prevent these erros in order to have a more robust installation system.

• How to solve the error?

Remove unnecessary circular dependencies when encountered.

Often the loops may be harmless, but sometimes they might cause packages to be installed in the wrong order, ie. like one package requiring a specific user for ownership of directories which are created by another package, or maybe running a script requiring a file from another package that due to dependency loop gets installed only after the script is attempted to run..

• In practical, how to solve this?

Edit the spec file of the application to remove unnecessary circular dependencies.

If not possible, add the dependency detection to this bug report in bugzilla or create a new bug linking to it.

Rpmlint errors

Rpmlint errors and warnings are described in a separate page

See Also

• This page is partially inspired by Mandriva's packaging problems page.