samples/bpf: add tracepoint support to bpf loader

Recognize "tracepoint/" section name prefix and attach the program
to that tracepoint.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 5 deletions

diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 58f86bd11b3d..022af71c2bb5 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c
@@ -49,6 +49,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
         bool is_socket = strncmp(event, "socket", 6) == 0;
         bool is_kprobe = strncmp(event, "kprobe/", 7) == 0;
         bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
+        bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0;
         enum bpf_prog_type prog_type;
         char buf[256];
         int fd, efd, err, id;
@@ -63,6 +64,8 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
                 prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
         } else if (is_kprobe || is_kretprobe) {
                 prog_type = BPF_PROG_TYPE_KPROBE;
+        } else if (is_tracepoint) {
+                prog_type = BPF_PROG_TYPE_TRACEPOINT;
         } else {
                 printf("Unknown event '%s'\n", event);
                 return -1;
@@ -111,12 +114,23 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
                                event, strerror(errno));
                         return -1;
                 }
-        }
 
-        strcpy(buf, DEBUGFS);
-        strcat(buf, "events/kprobes/");
-        strcat(buf, event);
-        strcat(buf, "/id");
+                strcpy(buf, DEBUGFS);
+                strcat(buf, "events/kprobes/");
+                strcat(buf, event);
+                strcat(buf, "/id");
+        } else if (is_tracepoint) {
+                event += 11;
+
+                if (*event == 0) {
+                        printf("event name cannot be empty\n");
+                        return -1;
+                }
+                strcpy(buf, DEBUGFS);
+                strcat(buf, "events/");
+                strcat(buf, event);
+                strcat(buf, "/id");
+        }
 
         efd = open(buf, O_RDONLY, 0);
         if (efd < 0) {
@@ -304,6 +318,7 @@ int load_bpf_file(char *path)
 
                         if (memcmp(shname_prog, "kprobe/", 7) == 0 ||
                             memcmp(shname_prog, "kretprobe/", 10) == 0 ||
+                            memcmp(shname_prog, "tracepoint/", 11) == 0 ||
                             memcmp(shname_prog, "socket", 6) == 0)
                                 load_and_attach(shname_prog, insns, data_prog->d_size);
                 }
@@ -320,6 +335,7 @@ int load_bpf_file(char *path)
 
                 if (memcmp(shname, "kprobe/", 7) == 0 ||
                     memcmp(shname, "kretprobe/", 10) == 0 ||
+                    memcmp(shname, "tracepoint/", 11) == 0 ||
                     memcmp(shname, "socket", 6) == 0)
                         load_and_attach(shname, data->d_buf, data->d_size);
         }