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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
char _license[] SEC("license") = "GPL";
uint32_t tid = 0;
int num_unknown_tid = 0;
int num_known_tid = 0;
SEC("iter/task")
int dump_task(struct bpf_iter__task *ctx)
{
struct seq_file *seq = ctx->meta->seq;
struct task_struct *task = ctx->task;
static char info[] = " === END ===";
if (task == (void *)0) {
BPF_SEQ_PRINTF(seq, "%s\n", info);
return 0;
}
if (task->pid != (pid_t)tid)
num_unknown_tid++;
else
num_known_tid++;
if (ctx->meta->seq_num == 0)
BPF_SEQ_PRINTF(seq, " tgid gid\n");
BPF_SEQ_PRINTF(seq, "%8d %8d\n", task->tgid, task->pid);
return 0;
}
int num_expected_failure_copy_from_user_task = 0;
int num_success_copy_from_user_task = 0;
SEC("iter.s/task")
int dump_task_sleepable(struct bpf_iter__task *ctx)
{
struct seq_file *seq = ctx->meta->seq;
struct task_struct *task = ctx->task;
static const char info[] = " === END ===";
struct pt_regs *regs;
void *ptr;
uint32_t user_data = 0;
int ret;
if (task == (void *)0) {
BPF_SEQ_PRINTF(seq, "%s\n", info);
return 0;
}
/* Read an invalid pointer and ensure we get an error */
ptr = NULL;
ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);
if (ret) {
++num_expected_failure_copy_from_user_task;
} else {
BPF_SEQ_PRINTF(seq, "%s\n", info);
return 0;
}
/* Try to read the contents of the task's instruction pointer from the
* remote task's address space.
*/
regs = (struct pt_regs *)bpf_task_pt_regs(task);
if (regs == (void *)0) {
BPF_SEQ_PRINTF(seq, "%s\n", info);
return 0;
}
ptr = (void *)PT_REGS_IP(regs);
ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);
if (ret) {
BPF_SEQ_PRINTF(seq, "%s\n", info);
return 0;
}
++num_success_copy_from_user_task;
if (ctx->meta->seq_num == 0)
BPF_SEQ_PRINTF(seq, " tgid gid data\n");
BPF_SEQ_PRINTF(seq, "%8d %8d %8d\n", task->tgid, task->pid, user_data);
return 0;
}
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