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fix format of 35 user ring buffer

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This commit is contained in:
yunwei37
2023-10-21 12:41:54 +00:00
parent 4602557478
commit 002bcaeaea
3 changed files with 42 additions and 27 deletions
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3
src/35-user-ringbuf/README.md Normal file
View File

@@ -0,0 +1,3 @@
# user ring buffer
maps between kernel and userspace

9
src/35-user-ringbuf/user_ringbuf.bpf.c
View File

@@ -9,12 +9,14 @@
char _license[] SEC("license") = "GPL";
struct {
struct
{
__uint(type, BPF_MAP_TYPE_USER_RINGBUF);
__uint(max_entries, 256 * 1024);
} user_ringbuf SEC(".maps");
struct {
struct
{
__uint(type, BPF_MAP_TYPE_RINGBUF);
__uint(max_entries, 256 * 1024);
} kernel_ringbuf SEC(".maps");
@@ -48,7 +50,8 @@ int kill_exit(struct trace_event_raw_sys_exit *ctx)
{
long num_samples;
int err = 0;
// receive data from userspace
num_samples = bpf_user_ringbuf_drain(&user_ringbuf, do_nothing_cb, NULL, 0);
return 0;

57
src/35-user-ringbuf/user_ringbuf.c
View File

@@ -20,25 +20,27 @@ static int write_samples(struct user_ring_buffer *ringbuf)
struct user_sample *entry;
entry = user_ring_buffer__reserve(ringbuf, sizeof(*entry));
if (!entry) {
if (!entry)
{
err = -errno;
goto done;
}
entry->i = getpid();
strcpy(entry->comm, "hello");
entry->i = getpid();
strcpy(entry->comm, "hello");
int read = snprintf(entry->comm, sizeof(entry->comm), "%u", i);
if (read <= 0) {
/* Assert on the error path to avoid spamming logs with
* mostly success messages.
*/
err = read;
user_ring_buffer__discard(ringbuf, entry);
goto done;
}
int read = snprintf(entry->comm, sizeof(entry->comm), "%u", i);
if (read <= 0)
{
/* Assert on the error path to avoid spamming logs with
* mostly success messages.
*/
err = read;
user_ring_buffer__discard(ringbuf, entry);
goto done;
}
user_ring_buffer__submit(ringbuf, entry);
user_ring_buffer__submit(ringbuf, entry);
done:
drain_current_samples();
@@ -58,7 +60,7 @@ static void sig_handler(int sig)
exiting = true;
}
struct user_ring_buffer *user_ringbuf = NULL;
struct user_ring_buffer *user_ringbuf = NULL;
static int handle_event(void *ctx, void *data, size_t data_sz)
{
@@ -71,8 +73,8 @@ static int handle_event(void *ctx, void *data, size_t data_sz)
tm = localtime(&t);
strftime(ts, sizeof(ts), "%H:%M:%S", tm);
printf("%-8s %-5s %-16s %-7d\n",
ts, "SIGN", e->comm, e->pid);
printf("%-8s %-5s %-16s %-7d\n",
ts, "SIGN", e->comm, e->pid);
write_samples(user_ringbuf);
return 0;
}
@@ -92,7 +94,8 @@ int main(int argc, char **argv)
/* Load and verify BPF application */
skel = user_ringbuf_bpf__open();
if (!skel) {
if (!skel)
{
fprintf(stderr, "Failed to open and load BPF skeleton\n");
return 1;
}
@@ -102,21 +105,24 @@ int main(int argc, char **argv)
/* Load & verify BPF programs */
err = user_ringbuf_bpf__load(skel);
if (err) {
if (err)
{
fprintf(stderr, "Failed to load and verify BPF skeleton\n");
goto cleanup;
}
/* Attach tracepoints */
err = user_ringbuf_bpf__attach(skel);
if (err) {
if (err)
{
fprintf(stderr, "Failed to attach BPF skeleton\n");
goto cleanup;
}
/* Set up ring buffer polling */
rb = ring_buffer__new(bpf_map__fd(skel->maps.kernel_ringbuf), handle_event, NULL, NULL);
if (!rb) {
if (!rb)
{
err = -1;
fprintf(stderr, "Failed to create ring buffer\n");
goto cleanup;
@@ -127,15 +133,18 @@ int main(int argc, char **argv)
/* Process events */
printf("%-8s %-5s %-16s %-7s %-7s %s\n",
"TIME", "EVENT", "COMM", "PID", "PPID", "FILENAME/EXIT CODE");
while (!exiting) {
"TIME", "EVENT", "COMM", "PID", "PPID", "FILENAME/EXIT CODE");
while (!exiting)
{
err = ring_buffer__poll(rb, 100 /* timeout, ms */);
/* Ctrl-C will cause -EINTR */
if (err == -EINTR) {
if (err == -EINTR)
{
err = 0;
break;
}
if (err < 0) {
if (err < 0)
{
printf("Error polling perf buffer: %d\n", err);
break;
}