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bpf tools: Load eBPF programs in object files into kernel

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This patch utilizes previous introduced bpf_load_program to load
programs in the ELF file into kernel. Result is stored in 'fd' field in
'struct bpf_program'.

During loading, it allocs a log buffer and free it before return.  Note
that that buffer is not passed to bpf_load_program() if the first
loading try is successful. Doesn't use a statically allocated log buffer
to avoid potention multi-thread problem.

Instructions collected during opening is cleared after loading.

load_program() is created for loading a 'struct bpf_insn' array into
kernel, bpf_program__load() calls it. By this design we have a function
loads instructions into kernel. It will be used by further patches,
which creates different instances from a program and load them into
kernel.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1435716878-189507-20-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Wang Nan 2015-07-01 02:14:07 +00:00 committed by Arnaldo Carvalho de Melo
parent 7bf98369a7
commit 55cffde2e1
1 changed files with 90 additions and 0 deletions
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90
tools/lib/bpf/libbpf.c
View File

@ -96,6 +96,8 @@ struct bpf_program {
int map_idx;
} *reloc_desc;
int nr_reloc;
int fd;
};
struct bpf_object {
@ -135,11 +137,20 @@ struct bpf_object {
};
#define obj_elf_valid(o) ((o)->efile.elf)
static void bpf_program__unload(struct bpf_program *prog)
{
if (!prog)
return;
zclose(prog->fd);
}
static void bpf_program__exit(struct bpf_program *prog)
{
if (!prog)
return;
bpf_program__unload(prog);
zfree(&prog->section_name);
zfree(&prog->insns);
zfree(&prog->reloc_desc);
@ -176,6 +187,7 @@ bpf_program__init(void *data, size_t size, char *name, int idx,
memcpy(prog->insns, data,
prog->insns_cnt * sizeof(struct bpf_insn));
prog->idx = idx;
prog->fd = -1;
return 0;
errout:
@ -718,6 +730,79 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
return 0;
}
static int
load_program(struct bpf_insn *insns, int insns_cnt,
char *license, u32 kern_version, int *pfd)
{
int ret;
char *log_buf;
if (!insns || !insns_cnt)
return -EINVAL;
log_buf = malloc(BPF_LOG_BUF_SIZE);
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);
if (ret >= 0) {
*pfd = ret;
ret = 0;
goto out;
}
ret = -EINVAL;
pr_warning("load bpf program failed: %s\n", strerror(errno));
if (log_buf) {
pr_warning("-- BEGIN DUMP LOG ---\n");
pr_warning("\n%s\n", log_buf);
pr_warning("-- END LOG --\n");
}
out:
free(log_buf);
return ret;
}
static int
bpf_program__load(struct bpf_program *prog,
char *license, u32 kern_version)
{
int err, fd;
err = load_program(prog->insns, prog->insns_cnt,
license, kern_version, &fd);
if (!err)
prog->fd = fd;
if (err)
pr_warning("failed to load program '%s'\n",
prog->section_name);
zfree(&prog->insns);
prog->insns_cnt = 0;
return err;
}
static int
bpf_object__load_progs(struct bpf_object *obj)
{
size_t i;
int err;
for (i = 0; i < obj->nr_programs; i++) {
err = bpf_program__load(&obj->programs[i],
obj->license,
obj->kern_version);
if (err)
return err;
}
return 0;
}
static int bpf_object__validate(struct bpf_object *obj)
{
if (obj->kern_version == 0) {
@ -795,6 +880,9 @@ int bpf_object__unload(struct bpf_object *obj)
zfree(&obj->map_fds);
obj->nr_map_fds = 0;
for (i = 0; i < obj->nr_programs; i++)
bpf_program__unload(&obj->programs[i]);
return 0;
}
@ -813,6 +901,8 @@ int bpf_object__load(struct bpf_object *obj)
goto out;
if (bpf_object__relocate(obj))
goto out;
if (bpf_object__load_progs(obj))
goto out;
return 0;
out: