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1// SPDX-License-Identifier: GPL-2.02/* Copyright (c) 2020 Facebook */3#include "bpf_iter.h"4#include <bpf/bpf_helpers.h>5#include <bpf/bpf_tracing.h>6 7char _license[] SEC("license") = "GPL";8 9uint32_t tid = 0;10int num_unknown_tid = 0;11int num_known_tid = 0;12 13SEC("iter/task")14int dump_task(struct bpf_iter__task *ctx)15{16 struct seq_file *seq = ctx->meta->seq;17 struct task_struct *task = ctx->task;18 static char info[] = " === END ===";19 20 if (task == (void *)0) {21 BPF_SEQ_PRINTF(seq, "%s\n", info);22 return 0;23 }24 25 if (task->pid != (pid_t)tid)26 num_unknown_tid++;27 else28 num_known_tid++;29 30 if (ctx->meta->seq_num == 0)31 BPF_SEQ_PRINTF(seq, " tgid gid\n");32 33 BPF_SEQ_PRINTF(seq, "%8d %8d\n", task->tgid, task->pid);34 return 0;35}36 37int num_expected_failure_copy_from_user_task = 0;38int num_success_copy_from_user_task = 0;39 40SEC("iter.s/task")41int dump_task_sleepable(struct bpf_iter__task *ctx)42{43 struct seq_file *seq = ctx->meta->seq;44 struct task_struct *task = ctx->task;45 static const char info[] = " === END ===";46 struct pt_regs *regs;47 void *ptr;48 uint32_t user_data = 0;49 int ret;50 51 if (task == (void *)0) {52 BPF_SEQ_PRINTF(seq, "%s\n", info);53 return 0;54 }55 56 /* Read an invalid pointer and ensure we get an error */57 ptr = NULL;58 ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);59 if (ret) {60 ++num_expected_failure_copy_from_user_task;61 } else {62 BPF_SEQ_PRINTF(seq, "%s\n", info);63 return 0;64 }65 66 /* Try to read the contents of the task's instruction pointer from the67 * remote task's address space.68 */69 regs = (struct pt_regs *)bpf_task_pt_regs(task);70 if (regs == (void *)0) {71 BPF_SEQ_PRINTF(seq, "%s\n", info);72 return 0;73 }74 ptr = (void *)PT_REGS_IP(regs);75 76 ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);77 if (ret) {78 BPF_SEQ_PRINTF(seq, "%s\n", info);79 return 0;80 }81 ++num_success_copy_from_user_task;82 83 if (ctx->meta->seq_num == 0)84 BPF_SEQ_PRINTF(seq, " tgid gid data\n");85 86 BPF_SEQ_PRINTF(seq, "%8d %8d %8d\n", task->tgid, task->pid, user_data);87 return 0;88}89