• Vitaly Chikunov's avatar
    tools lib: Fix builds when glibc contains strlcpy() · 6d6c4c1b
    Vitaly Chikunov authored
    commit 6c4798d3 upstream.
    
    Disable a couple of compilation warnings (which are treated as errors)
    on strlcpy() definition and declaration, allowing users to compile perf
    and kernel (objtool) when:
    
    1. glibc have strlcpy() (such as in ALT Linux since 2004) objtool and
       perf build fails with this (in gcc):
    
      In file included from exec-cmd.c:3:
      tools/include/linux/string.h:20:15: error: redundant redeclaration of ‘strlcpy’ [-Werror=redundant-decls]
         20 | extern size_t strlcpy(char *dest, const char *src, size_t size);
    
    2. clang ignores `-Wredundant-decls', but produces another warning when
       building perf:
    
        CC       util/string.o
      ../lib/string.c:99:8: error: attribute declaration must precede definition [-Werror,-Wignored-attributes]
      size_t __weak strlcpy(char *dest, const char *src, size_t size)
      ../../tools/include/linux/compiler.h:66:34: note: expanded from macro '__weak'
      # define __weak                 __attribute__((weak))
      /usr/include/bits/string_fortified.h:151:8: note: previous definition is here
      __NTH (strlcpy (char *__restrict __dest, const char *__restrict __src,
    
    Committer notes:
    
    The
    
     #pragma GCC diagnostic
    
    directive was introduced in gcc 4.6, so check for that as well.
    
    Fixes: ce990917 ("perf tools: Move strlcpy() from perf to tools/lib/string.c")
    Fixes: 0215d59b ("tools lib: Reinstate strlcpy() header guard with __UCLIBC__")
    Resolves: https://bugzilla.kernel.org/show_bug.cgi?id=118481Signed-off-by: default avatarVitaly Chikunov <vt@altlinux.org>
    Reviewed-by: default avatarDmitry Levin <ldv@altlinux.org>
    Cc: Dmitry Levin <ldv@altlinux.org>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: kbuild test robot <lkp@intel.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: stable@vger.kernel.org
    Cc: Vineet Gupta <vineet.gupta1@synopsys.com>
    Link: http://lore.kernel.org/lkml/20191224172029.19690-1-vt@altlinux.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    6d6c4c1b
string.c 2.29 KB