From: Vitaly Chikunov vt@altlinux.org

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: ce99091 ("perf tools: Move strlcpy() from perf to tools/lib/string.c") Fixes: 0215d59 ("tools lib: Reinstate strlcpy() header guard with __UCLIBC__") Resolves: https://bugzilla.kernel.org/show_bug.cgi?id=118481 Signed-off-by: Vitaly Chikunov vt@altlinux.org Reviewed-by: Dmitry 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.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com --- tools/include/linux/string.h | 8 ++++++++ tools/lib/string.c | 7 +++++++ 2 files changed, 15 insertions(+)

diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h index 980cb9266718..5e9e781905ed 100644 --- a/tools/include/linux/string.h +++ b/tools/include/linux/string.h @@ -17,7 +17,15 @@ int strtobool(const char *s, bool *res); * However uClibc headers also define __GLIBC__ hence the hack below */ #if defined(__GLIBC__) && !defined(__UCLIBC__) +// pragma diagnostic was introduced in gcc 4.6 +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6) +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wredundant-decls" +#endif extern size_t strlcpy(char *dest, const char *src, size_t size); +#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6) +#pragma GCC diagnostic pop +#endif #endif

char *str_error_r(int errnum, char *buf, size_t buflen); diff --git a/tools/lib/string.c b/tools/lib/string.c index f2ae1b87c719..f645343815de 100644 --- a/tools/lib/string.c +++ b/tools/lib/string.c @@ -96,6 +96,10 @@ int strtobool(const char *s, bool *res) * If libc has strlcpy() then that version will override this * implementation: */ +#ifdef __clang__ +#pragma clang diagnostic push +#pragma clang diagnostic ignored "-Wignored-attributes" +#endif size_t __weak strlcpy(char *dest, const char *src, size_t size) { size_t ret = strlen(src); @@ -107,6 +111,9 @@ size_t __weak strlcpy(char *dest, const char *src, size_t size) } return ret; } +#ifdef __clang__ +#pragma clang diagnostic pop +#endif

/** * skip_spaces - Removes leading whitespace from @str.