On Tue, Nov 8, 2022 at 11:46 PM Sahid Orentino Ferdjaoui
<sahid.ferdjaoui@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> bpftool is now totally compliant with libbpf 1.0 mode and is not
> expected to be compiled with pre-1.0, let's clean-up the usage of
> libbpf_get_error().
>
> In some places functions that are returning result of
> libbpf_get_error() will now return errno. This won't impact the
> functionality as the caller checks for 0/non-0 for success/failure.
>
> sidenode: We can remove the checks on NULL pointers before calling
> btf__free() because that function already does the check.
>
> Signed-off-by: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@xxxxxxxxxxxxxxxxxxxxxxxx>
> ---
> tools/bpf/bpftool/btf.c | 17 +++++++----------
> tools/bpf/bpftool/btf_dumper.c | 2 +-
> tools/bpf/bpftool/gen.c | 11 ++++-------
> tools/bpf/bpftool/iter.c | 6 ++----
> tools/bpf/bpftool/main.c | 7 +++----
> tools/bpf/bpftool/map.c | 15 +++++++--------
> tools/bpf/bpftool/prog.c | 10 +++++-----
> tools/bpf/bpftool/struct_ops.c | 15 +++++++--------
> 8 files changed, 36 insertions(+), 47 deletions(-)
>
> diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
> index 68a70ac03c80..ed39b24e39d2 100644
> --- a/tools/bpf/bpftool/btf.c
> +++ b/tools/bpf/bpftool/btf.c
> @@ -467,9 +467,8 @@ static int dump_btf_c(const struct btf *btf,
> int err = 0, i;
>
> d = btf_dump__new(btf, btf_dump_printf, NULL, NULL);
> - err = libbpf_get_error(d);
> - if (err)
> - return err;
> + if (!d)
> + return errno;
-errno
>
> printf("#ifndef __VMLINUX_H__\n");
> printf("#define __VMLINUX_H__\n");
> @@ -512,11 +511,9 @@ static struct btf *get_vmlinux_btf_from_sysfs(void)
> struct btf *base;
>
> base = btf__parse(sysfs_vmlinux, NULL);
> - if (libbpf_get_error(base)) {
> - p_err("failed to parse vmlinux BTF at '%s': %ld\n",
> - sysfs_vmlinux, libbpf_get_error(base));
> - base = NULL;
> - }
> + if (!base)
> + p_err("failed to parse vmlinux BTF at '%s': %d\n",
> + sysfs_vmlinux, errno);
to be exactly the same: -errno (errno is always positive, while
returned error is always negative)
>
> return base;
> }
> @@ -634,8 +631,8 @@ static int do_dump(int argc, char **argv)
> base = get_vmlinux_btf_from_sysfs();
>
> btf = btf__parse_split(*argv, base ?: base_btf);
> - err = libbpf_get_error(btf);
you are removing setting err to actual value returned by libbpf. I
don't know if that matters, but it's certainly a change. Now on error
you'll always return -1. Please check if that has any unexpected
effect on calling code.
> if (!btf) {
> + err = errno;
-errno
> p_err("failed to load BTF from %s: %s",
> *argv, strerror(errno));
> goto done;
> @@ -681,8 +678,8 @@ static int do_dump(int argc, char **argv)
> }
>
> btf = btf__load_from_kernel_by_id_split(btf_id, base_btf);
> - err = libbpf_get_error(btf);
> if (!btf) {
> + err = errno;
same
> p_err("get btf by id (%u): %s", btf_id, strerror(errno));
> goto done;
> }
> diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
> index 19924b6ce796..eda71fdfe95a 100644
> --- a/tools/bpf/bpftool/btf_dumper.c
> +++ b/tools/bpf/bpftool/btf_dumper.c
> @@ -75,7 +75,7 @@ static int dump_prog_id_as_func_ptr(const struct btf_dumper *d,
> goto print;
>
> prog_btf = btf__load_from_kernel_by_id(info.btf_id);
> - if (libbpf_get_error(prog_btf))
> + if (!prog_btf)
> goto print;
> func_type = btf__type_by_id(prog_btf, finfo.type_id);
> if (!func_type || !btf_is_func(func_type))
> diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
> index cf8b4e525c88..d00b4e1b99ba 100644
> --- a/tools/bpf/bpftool/gen.c
> +++ b/tools/bpf/bpftool/gen.c
> @@ -252,9 +252,8 @@ static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
> int err = 0;
>
> d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL);
> - err = libbpf_get_error(d);
> - if (err)
> - return err;
> + if (!d)
> + return errno;
-errno
>
> bpf_object__for_each_map(map, obj) {
> /* only generate definitions for memory-mapped internal maps */
> @@ -976,13 +975,11 @@ static int do_skeleton(int argc, char **argv)
> /* log_level1 + log_level2 + stats, but not stable UAPI */
> opts.kernel_log_level = 1 + 2 + 4;
> obj = bpf_object__open_mem(obj_data, file_sz, &opts);
> - err = libbpf_get_error(obj);
> - if (err) {
> + if (!obj) {
> char err_buf[256];
>
> - libbpf_strerror(err, err_buf, sizeof(err_buf));
> + libbpf_strerror(errno, err_buf, sizeof(err_buf));
in this case doesn't matter, as libbpf_strerror drops the sign anyway
> p_err("failed to open BPF object file: %s", err_buf);
> - obj = NULL;
> goto out;
> }
>
[...]
