From: Vitaly Chikunov <vt@xxxxxxxxxxxx>
commit 6c4798d3f08b81c2c52936b10e0fa872590c96ae 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: 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@xxxxxxxxxxxx>
Reviewed-by: Dmitry Levin <ldv@xxxxxxxxxxxx>
Cc: Dmitry Levin <ldv@xxxxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: kbuild test robot <lkp@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Cc: Vineet Gupta <vineet.gupta1@xxxxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20191224172029.19690-1-vt@xxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/include/linux/string.h | 8 ++++++++
tools/lib/string.c | 7 +++++++
2 files changed, 15 insertions(+)
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -14,7 +14,15 @@ 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);
--- a/tools/lib/string.c
+++ b/tools/lib/string.c
@@ -95,6 +95,10 @@ 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);
@@ -106,3 +110,6 @@ size_t __weak strlcpy(char *dest, const
}
return ret;
}
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
