On Thu, Jul 25, 2024 at 3:39 AM Tony Ambardar <tony.ambardar@xxxxxxxxx> wrote:
>
> From: Tony Ambardar <tony.ambardar@xxxxxxxxx>
>
> Use backtrace functions only with glibc and otherwise provide stubs in
> test_progs.c. This avoids compile errors (e.g. with musl libc) like:
>
> test_progs.c:13:10: fatal error: execinfo.h: No such file or directory
> 13 | #include <execinfo.h> /* backtrace */
> | ^~~~~~~~~~~~
> test_progs.c: In function 'crash_handler':
> test_progs.c:1034:14: error: implicit declaration of function 'backtrace' [-Werror=implicit-function-declaration]
> 1034 | sz = backtrace(bt, ARRAY_SIZE(bt));
> | ^~~~~~~~~
> test_progs.c:1045:9: error: implicit declaration of function 'backtrace_symbols_fd' [-Werror=implicit-function-declaration]
> 1045 | backtrace_symbols_fd(bt, sz, STDERR_FILENO);
> | ^~~~~~~~~~~~~~~~~~~~
>
> Fixes: 9fb156bb82a3 ("selftests/bpf: Print backtrace on SIGSEGV in test_progs")
> Signed-off-by: Tony Ambardar <tony.ambardar@xxxxxxxxx>
> ---
> tools/testing/selftests/bpf/test_progs.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
> index 60c5ec0f6abf..f6cfc6a8e8f0 100644
> --- a/tools/testing/selftests/bpf/test_progs.c
> +++ b/tools/testing/selftests/bpf/test_progs.c
> @@ -10,7 +10,6 @@
> #include <sched.h>
> #include <signal.h>
> #include <string.h>
> -#include <execinfo.h> /* backtrace */
> #include <sys/sysinfo.h> /* get_nprocs */
> #include <netinet/in.h>
> #include <sys/select.h>
> @@ -19,6 +18,14 @@
> #include <bpf/btf.h>
> #include "json_writer.h"
>
> +#ifdef __GLIBC__
> +#include <execinfo.h> /* backtrace */
> +#else
> +#define backtrace(...) (0)
> +#define backtrace_symbols_fd(bt, sz, fd) \
> + dprintf(fd, "<backtrace not supported>\n", bt, sz)
> +#endif
First, let's define backtrace() and backtrace_symbols_fd() as proper
functions, not a macro?
And second, what if we then make those functions __weak, so they
provide default implementations if libc doesn't provide those
functions?
This parts seems unavoidable, though:
#ifdef __GLIBC__
#include <execinfo.h>
#endif
> +
> static bool verbose(void)
> {
> return env.verbosity > VERBOSE_NONE;
> --
> 2.34.1
>
