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 SEC("iter/task") 10 int dump_task(struct bpf_iter__task *ctx) 11 { 12 struct seq_file *seq = ctx->meta->seq; 13 struct task_struct *task = ctx->task; 14 static char info[] = " === END ==="; 15 16 if (task == (void *)0) { 17 BPF_SEQ_PRINTF(seq, "%s\n", info); 18 return 0; 19 } 20 21 if (ctx->meta->seq_num == 0) 22 BPF_SEQ_PRINTF(seq, " tgid gid\n"); 23 24 BPF_SEQ_PRINTF(seq, "%8d %8d\n", task->tgid, task->pid); 25 return 0; 26 } 27 28 int num_expected_failure_copy_from_user_task = 0; 29 int num_success_copy_from_user_task = 0; 30 31 SEC("iter.s/task") 32 int dump_task_sleepable(struct bpf_iter__task *ctx) 33 { 34 struct seq_file *seq = ctx->meta->seq; 35 struct task_struct *task = ctx->task; 36 static const char info[] = " === END ==="; 37 struct pt_regs *regs; 38 void *ptr; 39 uint32_t user_data = 0; 40 int ret; 41 42 if (task == (void *)0) { 43 BPF_SEQ_PRINTF(seq, "%s\n", info); 44 return 0; 45 } 46 47 /* Read an invalid pointer and ensure we get an error */ 48 ptr = NULL; 49 ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0); 50 if (ret) { 51 ++num_expected_failure_copy_from_user_task; 52 } else { 53 BPF_SEQ_PRINTF(seq, "%s\n", info); 54 return 0; 55 } 56 57 /* Try to read the contents of the task's instruction pointer from the 58 * remote task's address space. 59 */ 60 regs = (struct pt_regs *)bpf_task_pt_regs(task); 61 if (regs == (void *)0) { 62 BPF_SEQ_PRINTF(seq, "%s\n", info); 63 return 0; 64 } 65 ptr = (void *)PT_REGS_IP(regs); 66 67 ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0); 68 if (ret) { 69 BPF_SEQ_PRINTF(seq, "%s\n", info); 70 return 0; 71 } 72 ++num_success_copy_from_user_task; 73 74 if (ctx->meta->seq_num == 0) 75 BPF_SEQ_PRINTF(seq, " tgid gid data\n"); 76 77 BPF_SEQ_PRINTF(seq, "%8d %8d %8d\n", task->tgid, task->pid, user_data); 78 return 0; 79 } 80