1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2020 Facebook */ 3 #include "bpf_iter.h" 4 #include <bpf/bpf_helpers.h> 5 #include <bpf/bpf_tracing.h> 6 7 char _license[] SEC("license") = "GPL"; 8 9 uint32_t tid = 0; 10 int num_unknown_tid = 0; 11 int num_known_tid = 0; 12 13 SEC("iter/task") 14 int 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 else 28 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 37 int num_expected_failure_copy_from_user_task = 0; 38 int num_success_copy_from_user_task = 0; 39 40 SEC("iter.s/task") 41 int 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 the 67 * 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