tools/perf/util/bpf_trace_augment.c

Source file repositories/reference/linux-study-clean/tools/perf/util/bpf_trace_augment.c

File Facts

System
Linux kernel
Corpus path
tools/perf/util/bpf_trace_augment.c
Extension
.c
Size
3259 bytes
Lines
144
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <bpf/libbpf.h>
#include <internal/xyarray.h>

#include "util/debug.h"
#include "util/evlist.h"
#include "util/trace_augment.h"

#include "bpf_skel/augmented_raw_syscalls.skel.h"

static struct augmented_raw_syscalls_bpf *skel;
static struct evsel *bpf_output;

int augmented_syscalls__prepare(void)
{
	struct bpf_program *prog;
	char buf[128];
	int err;

	skel = augmented_raw_syscalls_bpf__open();
	if (!skel) {
		pr_debug("Failed to open augmented syscalls BPF skeleton\n");
		return -errno;
	}

	/*
	 * Disable attaching the BPF programs except for sys_enter and
	 * sys_exit that tail call into this as necessary.
	 */
	bpf_object__for_each_program(prog, skel->obj) {
		if (prog != skel->progs.sys_enter && prog != skel->progs.sys_exit)
			bpf_program__set_autoattach(prog, /*autoattach=*/false);
	}

	err = augmented_raw_syscalls_bpf__load(skel);
	if (err < 0) {
		libbpf_strerror(err, buf, sizeof(buf));
		pr_debug("Failed to load augmented syscalls BPF skeleton: %s\n", buf);
		return err;
	}

	augmented_raw_syscalls_bpf__attach(skel);
	return 0;
}

int augmented_syscalls__create_bpf_output(struct evlist *evlist)
{
	int err = parse_event(evlist, "bpf-output/no-inherit=1,name=__augmented_syscalls__/");

	if (err) {
		pr_err("ERROR: Setup BPF output event failed: %d\n", err);
		return err;
	}

	bpf_output = evlist__last(evlist);
	assert(evsel__name_is(bpf_output, "__augmented_syscalls__"));

	return 0;
}

void augmented_syscalls__setup_bpf_output(void)
{
	struct perf_cpu cpu;
	unsigned int i;

	if (bpf_output == NULL)
		return;

	/*
	 * Set up the __augmented_syscalls__ BPF map to hold for each
	 * CPU the bpf-output event's file descriptor.
	 */
	perf_cpu_map__for_each_cpu(cpu, i, bpf_output->core.cpus) {
		int mycpu = cpu.cpu;

		bpf_map__update_elem(skel->maps.__augmented_syscalls__,
				     &mycpu, sizeof(mycpu),
				     xyarray__entry(bpf_output->core.fd,
						    mycpu, 0),
				     sizeof(__u32), BPF_ANY);
	}
}

int augmented_syscalls__set_filter_pids(unsigned int nr, pid_t *pids)
{
	bool value = true;
	int err = 0;

	if (skel == NULL)
		return 0;

Annotation

Implementation Notes