From 1f235777c3a4ab115162fe7d45b82be534b9ae2e Mon Sep 17 00:00:00 2001 From: Hangbin Liu Date: Sat, 13 Aug 2022 08:09:36 +0800 Subject: [PATCH] libbpf: Making bpf_prog_load() ignore name if kernel doesn't support 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 Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20220813000936.6464-1-liuhangbin@gmail.com --- tools/lib/bpf/bpf.c | 6 ++---- tools/lib/bpf/libbpf.c | 13 +++++++++++-- tools/lib/bpf/libbpf_internal.h | 3 +++ 3 files changed, 16 insertions(+), 6 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 6a96e66..575867d 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 3f01f5c..aa05a99 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4415,14 +4415,23 @@ static int probe_fd(int fd) static int probe_kern_prog_name(void) { + const size_t attr_sz = offsetofend(union bpf_attr, prog_name); struct bpf_insn insns[] = { 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, attr_sz); + 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, "libbpf_nametest", 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, attr_sz, PROG_LOAD_ATTEMPTS); return probe_fd(ret); } diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 4135ae0..377642f 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 */ -- 2.7.4