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tools lib bpf: New API to adjust type of a BPF program
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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 <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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WangNan0 authored and acmel committed Jul 14, 2016
1 parent 1a4bf28 commit 5f44e4c
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Showing 2 changed files with 55 additions and 7 deletions.
53 changes: 46 additions & 7 deletions tools/lib/bpf/libbpf.c
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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:
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -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;
Expand Down
9 changes: 9 additions & 0 deletions tools/lib/bpf/libbpf.h
Original file line number Diff line number Diff line change
Expand Up @@ -164,6 +164,15 @@ 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.
Expand Down

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