Merge pull request iovisor#1336 from palmtenor/noinstance

Do not create instance for kprobe
drcwr · Sep 7, 2017 · 6aec309 · 6aec309
2 parents 08dbf13 + f4543fc
commit 6aec309
Showing 1 changed file with 6 additions and 28 deletions.
diff --git a/src/cc/libbpf.c b/src/cc/libbpf.c
@@ -392,12 +392,10 @@ void * bpf_attach_kprobe(int progfd, enum bpf_probe_attach_type attach_type, con
 {
  int kfd;
  char buf[256];
- char new_name[128];
+ char event_alias[128];
  struct perf_reader *reader = NULL;
  static char *event_type = "kprobe";
- int n;
 
- snprintf(new_name, sizeof(new_name), "%s_bcc_%d", ev_name, getpid());
  reader = perf_reader_new(cb, NULL, NULL, cb_cookie, probe_perf_reader_page_cnt);
  if (!reader)
  goto error;
@@ -409,8 +407,9 @@ void * bpf_attach_kprobe(int progfd, enum bpf_probe_attach_type attach_type, con
  goto error;
  }
 
+ snprintf(event_alias, sizeof(event_alias), "%s_bcc_%d", ev_name, getpid());
  snprintf(buf, sizeof(buf), "%c:%ss/%s %s", attach_type==BPF_PROBE_ENTRY ? 'p' : 'r',
- event_type, new_name, fn_name);
+ event_type, event_alias, fn_name);
  if (write(kfd, buf, strlen(buf)) < 0) {
  if (errno == EINVAL)
  fprintf(stderr, "check dmesg output for possible cause\n");
@@ -419,24 +418,10 @@ void * bpf_attach_kprobe(int progfd, enum bpf_probe_attach_type attach_type, con
  }
  close(kfd);
 
- if (access("/sys/kernel/debug/tracing/instances", F_OK) != -1) {
- snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/instances/bcc_%d", getpid());
- if (access(buf, F_OK) == -1) {
- if (mkdir(buf, 0755) == -1)
- goto retry;
- }
- n = snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/instances/bcc_%d/events/%ss/%s",
- getpid(), event_type, new_name);
- if (n < sizeof(buf) && bpf_attach_tracing_event(progfd, buf, reader, pid, cpu, group_fd) == 0)
- goto out;
- snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/instances/bcc_%d", getpid());
- rmdir(buf);
- }
-retry:
- snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s", event_type, new_name);
+ snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s", event_type, event_alias);
  if (bpf_attach_tracing_event(progfd, buf, reader, pid, cpu, group_fd) < 0)
  goto error;
-out:
+
  return reader;
 
 error:
@@ -586,14 +571,7 @@ static int bpf_detach_probe(const char *ev_name, const char *event_type)
 
 int bpf_detach_kprobe(const char *ev_name)
 {
- char buf[256];
- int ret = bpf_detach_probe(ev_name, "kprobe");
- snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/instances/bcc_%d", getpid());
- if (access(buf, F_OK) != -1) {
- rmdir(buf);
- }
-
- return ret;
+ return bpf_detach_probe(ev_name, "kprobe");
 }
 
 int bpf_detach_uprobe(const char *ev_name)