[PATCH 1/5] tools lib bpf: New API to adjust type of a BPF program

From: Wang Nan
Date: Wed Jul 13 2016 - 06:45:05 EST


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@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
---
tools/lib/bpf/libbpf.c | 53 +++++++++++++++++++++++++++++++++++++++++++-------
tools/lib/bpf/libbpf.h | 9 +++++++++
2 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 3dcda9e..4751936 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 f392c5e..eb2a4c4 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,
--
1.8.3.4