On 13/08/2022 01:09, Hangbin Liu wrote:
> Similar with commit 10b62d6a38f7 ("libbpf: Add names for auxiliary maps"),
> let's make bpf_prog_load() also ignore name if kernel doesn't support
> program name.
>
> To achieve this, we need to call sys_bpf_prog_load() directly in
> probe_kern_prog_name() to avoid circular dependency. sys_bpf_prog_load()
> also need to be exported in the libbpf_internal.h file.
>
> Signed-off-by: Hangbin Liu <liuhangbin@xxxxxxxxx>
> ---
> v2: move sys_bpf_prog_load definition to libbpf_internal.h. memset attr
> to 0 specifically to aviod padding.
> ---
> tools/lib/bpf/bpf.c | 6 ++----
> tools/lib/bpf/libbpf.c | 12 ++++++++++--
> tools/lib/bpf/libbpf_internal.h | 3 +++
> 3 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index 6a96e665dc5d..575867d69496 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -84,9 +84,7 @@ static inline int sys_bpf_fd(enum bpf_cmd cmd, union bpf_attr *attr,
> return ensure_good_fd(fd);
> }
>
> -#define PROG_LOAD_ATTEMPTS 5
> -
> -static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts)
> +int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts)
> {
> int fd;
>
> @@ -263,7 +261,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type,
> attr.prog_ifindex = OPTS_GET(opts, prog_ifindex, 0);
> attr.kern_version = OPTS_GET(opts, kern_version, 0);
>
> - if (prog_name)
> + if (prog_name && kernel_supports(NULL, FEAT_PROG_NAME))
> libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name));
> attr.license = ptr_to_u64(license);
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 3f01f5cd8a4c..4a351897bdcc 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -4419,10 +4419,18 @@ static int probe_kern_prog_name(void)
> BPF_MOV64_IMM(BPF_REG_0, 0),
> BPF_EXIT_INSN(),
> };
> - int ret, insn_cnt = ARRAY_SIZE(insns);
> + union bpf_attr attr;
> + int ret;
> +
> + memset(&attr, 0, sizeof(attr));
> + attr.prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
> + attr.license = ptr_to_u64("GPL");
> + attr.insns = ptr_to_u64(insns);
> + attr.insn_cnt = (__u32)ARRAY_SIZE(insns);
> + libbpf_strlcpy(attr.prog_name, "test", sizeof(attr.prog_name));
>
> /* make sure loading with name works */
> - ret = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "test", "GPL", insns, insn_cnt, NULL);
> + ret = sys_bpf_prog_load(&attr, sizeof(attr), PROG_LOAD_ATTEMPTS);
> return probe_fd(ret);
> }
>
> diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
> index 4135ae0a2bc3..377642ff51fc 100644
> --- a/tools/lib/bpf/libbpf_internal.h
> +++ b/tools/lib/bpf/libbpf_internal.h
> @@ -573,4 +573,7 @@ static inline bool is_pow_of_2(size_t x)
> return x && (x & (x - 1)) == 0;
> }
>
> +#define PROG_LOAD_ATTEMPTS 5
> +int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size, int attempts);
> +
> #endif /* __LIBBPF_LIBBPF_INTERNAL_H */
Looks good to me, thanks!
Acked-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
