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bpftool: Use a local copy of BPF_LINK_TYPE_PERF_EVENT in pid_iter.bpf.c

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In order to allow the BPF program in bpftool's pid_iter.bpf.c to compile
correctly on hosts where vmlinux.h does not define
BPF_LINK_TYPE_PERF_EVENT (running kernel versions lower than 5.15, for
example), define and use a local copy of the enum value. This requires
LLVM 12 or newer to build the BPF program.

Fixes: cbdaf71f7e ("bpftool: Add bpf_cookie to link output")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230707095425.168126-4-quentin@isovalent.com
This commit is contained in:
Quentin Monnet 2023-07-07 10:54:24 +01:00 committed by Andrii Nakryiko
parent 67a43462ee
commit 44ba7b30e8
1 changed files with 9 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

11
tools/bpf/bpftool/skeleton/pid_iter.bpf.c
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@ -24,6 +24,10 @@ struct perf_event___local {
u64 bpf_cookie;
} __attribute__((preserve_access_index));
enum bpf_link_type___local {
BPF_LINK_TYPE_PERF_EVENT___local = 7,
};
extern const void bpf_link_fops __ksym;
extern const void bpf_map_fops __ksym;
extern const void bpf_prog_fops __ksym;
@ -93,10 +97,13 @@ int iter(struct bpf_iter__task_file *ctx)
e.pid = task->tgid;
e.id = get_obj_id(file->private_data, obj_type);
if (obj_type == BPF_OBJ_LINK) {
if (obj_type == BPF_OBJ_LINK &&
bpf_core_enum_value_exists(enum bpf_link_type___local,
BPF_LINK_TYPE_PERF_EVENT___local)) {
struct bpf_link *link = (struct bpf_link *) file->private_data;
if (BPF_CORE_READ(link, type) == BPF_LINK_TYPE_PERF_EVENT) {
if (link->type == bpf_core_enum_value(enum bpf_link_type___local,
BPF_LINK_TYPE_PERF_EVENT___local)) {
e.has_bpf_cookie = true;
e.bpf_cookie = get_bpf_cookie(link);
}