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laoarKernel Patches Daemon
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selftests/bpf: Add selftest for cgroup_task iter
Add selftests for the newly introduced cgroup_task iter. The result: #42/1 cgroup_task_iter/cgroup_task_iter__invalid_order:OK #42/2 cgroup_task_iter/cgroup_task_iter__no_task:OK #42/3 cgroup_task_iter/cgroup_task_iter__task_pid:OK #42/4 cgroup_task_iter/cgroup_task_iter__task_cnt:OK #42 cgroup_task_iter:OK Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Yafang Shao <[email protected]>
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‎tools/testing/selftests/bpf/prog_tests/cgroup_task_iter.c

Lines changed: 197 additions & 0 deletions
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Yafang Shao <[email protected]> */
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#include <signal.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <test_progs.h>
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#include <bpf/libbpf.h>
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#include <bpf/btf.h>
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#include "cgroup_helpers.h"
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#include "cgroup_task_iter.skel.h"
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#define PID_CNT (2)
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static char expected_output[128];
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static void read_from_cgroup_iter(struct bpf_program *prog, int cgroup_fd,
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int order, const char *testname)
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{
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DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
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union bpf_iter_link_info linfo;
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struct bpf_link *link;
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int len, iter_fd;
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static char buf[128];
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size_t left;
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char *p;
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memset(&linfo, 0, sizeof(linfo));
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linfo.cgroup.cgroup_fd = cgroup_fd;
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linfo.cgroup.order = order;
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opts.link_info = &linfo;
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opts.link_info_len = sizeof(linfo);
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link = bpf_program__attach_iter(prog, &opts);
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if (!ASSERT_OK_PTR(link, "attach_iter"))
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return;
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iter_fd = bpf_iter_create(bpf_link__fd(link));
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if (iter_fd < 0)
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goto free_link;
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memset(buf, 0, sizeof(buf));
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left = ARRAY_SIZE(buf);
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p = buf;
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while ((len = read(iter_fd, p, left)) > 0) {
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p += len;
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left -= len;
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}
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ASSERT_STREQ(buf, expected_output, testname);
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/* read() after iter finishes should be ok. */
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if (len == 0)
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ASSERT_OK(read(iter_fd, buf, sizeof(buf)), "second_read");
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close(iter_fd);
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free_link:
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bpf_link__destroy(link);
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}
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/* Invalid walk order */
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static void test_invalid_order(struct cgroup_task_iter *skel, int fd)
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{
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DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts);
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enum bpf_cgroup_iter_order order;
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union bpf_iter_link_info linfo;
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struct bpf_link *link;
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memset(&linfo, 0, sizeof(linfo));
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linfo.cgroup.cgroup_fd = fd;
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opts.link_info = &linfo;
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opts.link_info_len = sizeof(linfo);
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/* Only BPF_CGROUP_ITER_SELF_ONLY is supported */
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for (order = 0; order <= BPF_CGROUP_ITER_ANCESTORS_UP; order++) {
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if (order == BPF_CGROUP_ITER_SELF_ONLY)
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continue;
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linfo.cgroup.order = order;
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link = bpf_program__attach_iter(skel->progs.cgroup_task_cnt, &opts);
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ASSERT_ERR_PTR(link, "attach_task_iter");
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ASSERT_EQ(errno, EINVAL, "error code on invalid walk order");
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}
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}
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/* Iterate a cgroup withouth any task */
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static void test_walk_no_task(struct cgroup_task_iter *skel, int fd)
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{
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snprintf(expected_output, sizeof(expected_output), "nr_total 0\n");
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read_from_cgroup_iter(skel->progs.cgroup_task_cnt, fd,
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BPF_CGROUP_ITER_SELF_ONLY, "self_only");
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}
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/* The forked child process do nothing. */
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static void child_sleep(void)
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{
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while (1)
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sleep(1);
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}
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/* Get task pid under a cgroup */
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static void test_walk_task_pid(struct cgroup_task_iter *skel, int fd)
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{
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int pid, status, err;
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char pid_str[16];
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pid = fork();
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if (!ASSERT_GE(pid, 0, "fork_task"))
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return;
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if (pid) {
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snprintf(pid_str, sizeof(pid_str), "%u", pid);
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err = write_cgroup_file("cgroup_task_iter", "cgroup.procs", pid_str);
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if (!ASSERT_EQ(err, 0, "write cgrp file"))
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goto out;
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snprintf(expected_output, sizeof(expected_output), "pid %u\n", pid);
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read_from_cgroup_iter(skel->progs.cgroup_task_pid, fd,
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BPF_CGROUP_ITER_SELF_ONLY, "self_only");
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out:
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kill(pid, SIGKILL);
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waitpid(pid, &status, 0);
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} else {
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child_sleep();
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}
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}
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/* Get task count under a cgroup */
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static void test_walk_task_cnt(struct cgroup_task_iter *skel, int fd)
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{
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int pids[PID_CNT], pid, status, err, i;
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char pid_str[16];
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for (i = 0; i < PID_CNT; i++)
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pids[i] = 0;
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for (i = 0; i < PID_CNT; i++) {
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pid = fork();
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if (!ASSERT_GE(pid, 0, "fork_task"))
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goto out;
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if (pid) {
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pids[i] = pid;
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snprintf(pid_str, sizeof(pid_str), "%u", pid);
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err = write_cgroup_file("cgroup_task_iter", "cgroup.procs", pid_str);
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if (!ASSERT_EQ(err, 0, "write cgrp file"))
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goto out;
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} else {
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child_sleep();
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}
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}
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snprintf(expected_output, sizeof(expected_output), "nr_total %u\n", PID_CNT);
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read_from_cgroup_iter(skel->progs.cgroup_task_cnt, fd,
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BPF_CGROUP_ITER_SELF_ONLY, "self_only");
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out:
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for (i = 0; i < PID_CNT; i++) {
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if (!pids[i])
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continue;
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kill(pids[i], SIGKILL);
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waitpid(pids[i], &status, 0);
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}
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}
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void test_cgroup_task_iter(void)
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{
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struct cgroup_task_iter *skel = NULL;
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int cgrp_fd;
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if (setup_cgroup_environment())
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return;
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cgrp_fd = create_and_get_cgroup("cgroup_task_iter");
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if (!ASSERT_GE(cgrp_fd, 0, "create cgrp"))
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goto cleanup_cgrp_env;
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skel = cgroup_task_iter__open_and_load();
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if (!ASSERT_OK_PTR(skel, "cgroup_task_iter__open_and_load"))
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goto out;
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if (test__start_subtest("cgroup_task_iter__invalid_order"))
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test_invalid_order(skel, cgrp_fd);
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if (test__start_subtest("cgroup_task_iter__no_task"))
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test_walk_no_task(skel, cgrp_fd);
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if (test__start_subtest("cgroup_task_iter__task_pid"))
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test_walk_task_pid(skel, cgrp_fd);
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if (test__start_subtest("cgroup_task_iter__task_cnt"))
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test_walk_task_cnt(skel, cgrp_fd);
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out:
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cgroup_task_iter__destroy(skel);
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close(cgrp_fd);
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remove_cgroup("cgroup_task_iter");
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cleanup_cgrp_env:
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cleanup_cgroup_environment();
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}

‎tools/testing/selftests/bpf/progs/cgroup_task_iter.c

Lines changed: 39 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,39 @@
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// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Yafang Shao <[email protected]> */
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#include "bpf_iter.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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char _license[] SEC("license") = "GPL";
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SEC("iter/cgroup_task")
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int cgroup_task_cnt(struct bpf_iter__cgroup_task *ctx)
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{
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struct seq_file *seq = ctx->meta->seq;
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struct task_struct *task = ctx->task;
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static __u32 nr_total;
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if (!task) {
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BPF_SEQ_PRINTF(seq, "nr_total %u\n", nr_total);
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return 0;
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}
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if (ctx->meta->seq_num == 0)
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nr_total = 0;
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nr_total++;
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return 0;
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}
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SEC("iter/cgroup_task")
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int cgroup_task_pid(struct bpf_iter__cgroup_task *ctx)
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{
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struct seq_file *seq = ctx->meta->seq;
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struct task_struct *task = ctx->task;
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if (!task)
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return 0;
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BPF_SEQ_PRINTF(seq, "pid %u\n", task->pid);
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return 0;
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}

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