tools lib bpf: New API to adjust type of a BPF program

Add 4 new APIs to adjust and query the type of a BPF program.
Load program according to type set by caller. Default is set to
BPF_PROG_TYPE_KPROBE.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1468406646-21642-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 55 insertions, 7 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 3dcda9e215b0..4751936831d7 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -158,6 +158,7 @@ struct bpf_program {
         char *section_name;
         struct bpf_insn *insns;
         size_t insns_cnt;
+        enum bpf_prog_type type;
 
         struct {
                 int insn_idx;
@@ -299,6 +300,7 @@ bpf_program__init(void *data, size_t size, char *name, int idx,
         prog->idx = idx;
         prog->instances.fds = NULL;
         prog->instances.nr = -1;
+        prog->type = BPF_PROG_TYPE_KPROBE;
 
         return 0;
 errout:
@@ -894,8 +896,8 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
 }
 
 static int
-load_program(struct bpf_insn *insns, int insns_cnt,
-             char *license, u32 kern_version, int *pfd)
+load_program(enum bpf_prog_type type, struct bpf_insn *insns,
+             int insns_cnt, char *license, u32 kern_version, int *pfd)
 {
         int ret;
         char *log_buf;
@@ -907,9 +909,8 @@ load_program(struct bpf_insn *insns, int insns_cnt,
         if (!log_buf)
                 pr_warning("Alloc log buffer for bpf loader error, continue without log\n");
 
-        ret = bpf_load_program(BPF_PROG_TYPE_KPROBE, insns,
-                               insns_cnt, license, kern_version,
-                               log_buf, BPF_LOG_BUF_SIZE);
+        ret = bpf_load_program(type, insns, insns_cnt, license,
+                               kern_version, log_buf, BPF_LOG_BUF_SIZE);
 
         if (ret >= 0) {
                 *pfd = ret;
@@ -968,7 +969,7 @@ bpf_program__load(struct bpf_program *prog,
                         pr_warning("Program '%s' is inconsistent: nr(%d) != 1\n",
                                    prog->section_name, prog->instances.nr);
                 }
-                err = load_program(prog->insns, prog->insns_cnt,
+                err = load_program(prog->type, prog->insns, prog->insns_cnt,
                                    license, kern_version, &fd);
                 if (!err)
                         prog->instances.fds[0] = fd;
@@ -997,7 +998,7 @@ bpf_program__load(struct bpf_program *prog,
                         continue;
                 }
 
-                err = load_program(result.new_insn_ptr,
+                err = load_program(prog->type, result.new_insn_ptr,
                                    result.new_insn_cnt,
                                    license, kern_version, &fd);
 
@@ -1316,6 +1317,44 @@ int bpf_program__nth_fd(struct bpf_program *prog, int n)
         return fd;
 }
 
+static void bpf_program__set_type(struct bpf_program *prog,
+                                  enum bpf_prog_type type)
+{
+        prog->type = type;
+}
+
+int bpf_program__set_tracepoint(struct bpf_program *prog)
+{
+        if (!prog)
+                return -EINVAL;
+        bpf_program__set_type(prog, BPF_PROG_TYPE_TRACEPOINT);
+        return 0;
+}
+
+int bpf_program__set_kprobe(struct bpf_program *prog)
+{
+        if (!prog)
+                return -EINVAL;
+        bpf_program__set_type(prog, BPF_PROG_TYPE_KPROBE);
+        return 0;
+}
+
+static bool bpf_program__is_type(struct bpf_program *prog,
+                                 enum bpf_prog_type type)
+{
+        return prog ? (prog->type == type) : false;
+}
+
+bool bpf_program__is_tracepoint(struct bpf_program *prog)
+{
+        return bpf_program__is_type(prog, BPF_PROG_TYPE_TRACEPOINT);
+}
+
+bool bpf_program__is_kprobe(struct bpf_program *prog)
+{
+        return bpf_program__is_type(prog, BPF_PROG_TYPE_KPROBE);
+}
+
 int bpf_map__fd(struct bpf_map *map)
 {
         return map ? map->fd : -EINVAL;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index f392c5e04cc1..eb2a4c45f6b6 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -165,6 +165,15 @@ int bpf_program__set_prep(struct bpf_program *prog, int nr_instance,
 int bpf_program__nth_fd(struct bpf_program *prog, int n);
 
 /*
+ * Adjust type of bpf program. Default is kprobe.
+ */
+int bpf_program__set_tracepoint(struct bpf_program *prog);
+int bpf_program__set_kprobe(struct bpf_program *prog);
+
+bool bpf_program__is_tracepoint(struct bpf_program *prog);
+bool bpf_program__is_kprobe(struct bpf_program *prog);
+
+/*
  * We don't need __attribute__((packed)) now since it is
  * unnecessary for 'bpf_map_def' because they are all aligned.
  * In addition, using it will trigger -Wpacked warning message,