diff mbox series

[bpf-next,v6,1/3] bpftool: Add auto_attach for bpf prog load|loadall

Message ID 1664014430-5286-1-git-send-email-wangyufen@huawei.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series [bpf-next,v6,1/3] bpftool: Add auto_attach for bpf prog load|loadall | expand

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Commit Message

wangyufen Sept. 24, 2022, 10:13 a.m. UTC 
Add auto_attach optional to support one-step load-attach-pin_link.

For example,
   $ bpftool prog loadall test.o /sys/fs/bpf/test autoattach

   $ bpftool link
   26: tracing  name test1  tag f0da7d0058c00236  gpl
   	loaded_at 2022-09-09T21:39:49+0800  uid 0
   	xlated 88B  jited 55B  memlock 4096B  map_ids 3
   	btf_id 55
   28: kprobe  name test3  tag 002ef1bef0723833  gpl
   	loaded_at 2022-09-09T21:39:49+0800  uid 0
   	xlated 88B  jited 56B  memlock 4096B  map_ids 3
   	btf_id 55
   57: tracepoint  name oncpu  tag 7aa55dfbdcb78941  gpl
   	loaded_at 2022-09-09T21:41:32+0800  uid 0
   	xlated 456B  jited 265B  memlock 4096B  map_ids 17,13,14,15
   	btf_id 82

   $ bpftool link
   1: tracing  prog 26
   	prog_type tracing  attach_type trace_fentry
   3: perf_event  prog 28
   10: perf_event  prog 57

The autoattach optional can support tracepoints, k(ret)probes,
u(ret)probes.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Wang Yufen <wangyufen@huawei.com>
---
v5 -> v6: skip the programs not supporting auto-attach,
	  and change optional name from "auto_attach" to "autoattach"
v4 -> v5: some formatting nits of doc
v3 -> v4: rename functions, update doc, bash and do_help()
v2 -> v3: switch to extend prog load command instead of extend perf
v2: https://patchwork.kernel.org/project/netdevbpf/patch/20220824033837.458197-1-weiyongjun1@huawei.com/
v1: https://patchwork.kernel.org/project/netdevbpf/patch/20220816151725.153343-1-weiyongjun1@huawei.com/
 tools/bpf/bpftool/prog.c | 76 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 74 insertions(+), 2 deletions(-)

Comments

Quentin Monnet Sept. 26, 2022, 10:46 a.m. UTC | #1 
Sat Sep 24 2022 11:13:48 GMT+0100 (British Summer Time) ~ Wang Yufen
<wangyufen@huawei.com>
> Add auto_attach optional to support one-step load-attach-pin_link.
> 
> For example,
>    $ bpftool prog loadall test.o /sys/fs/bpf/test autoattach
> 
>    $ bpftool link
>    26: tracing  name test1  tag f0da7d0058c00236  gpl
>    	loaded_at 2022-09-09T21:39:49+0800  uid 0
>    	xlated 88B  jited 55B  memlock 4096B  map_ids 3
>    	btf_id 55
>    28: kprobe  name test3  tag 002ef1bef0723833  gpl
>    	loaded_at 2022-09-09T21:39:49+0800  uid 0
>    	xlated 88B  jited 56B  memlock 4096B  map_ids 3
>    	btf_id 55
>    57: tracepoint  name oncpu  tag 7aa55dfbdcb78941  gpl
>    	loaded_at 2022-09-09T21:41:32+0800  uid 0
>    	xlated 456B  jited 265B  memlock 4096B  map_ids 17,13,14,15
>    	btf_id 82
> 
>    $ bpftool link
>    1: tracing  prog 26
>    	prog_type tracing  attach_type trace_fentry
>    3: perf_event  prog 28
>    10: perf_event  prog 57
> 
> The autoattach optional can support tracepoints, k(ret)probes,
> u(ret)probes.
> 
> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
> Signed-off-by: Wang Yufen <wangyufen@huawei.com>
> ---
> v5 -> v6: skip the programs not supporting auto-attach,
> 	  and change optional name from "auto_attach" to "autoattach"
> v4 -> v5: some formatting nits of doc
> v3 -> v4: rename functions, update doc, bash and do_help()
> v2 -> v3: switch to extend prog load command instead of extend perf
> v2: https://patchwork.kernel.org/project/netdevbpf/patch/20220824033837.458197-1-weiyongjun1@huawei.com/
> v1: https://patchwork.kernel.org/project/netdevbpf/patch/20220816151725.153343-1-weiyongjun1@huawei.com/
>  tools/bpf/bpftool/prog.c | 76 ++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 74 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> index c81362a001ba..b1cbd06dee19 100644
> --- a/tools/bpf/bpftool/prog.c
> +++ b/tools/bpf/bpftool/prog.c
> @@ -1453,6 +1453,67 @@ get_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
>  	return ret;
>  }
>  
> +static int
> +auto_attach_program(struct bpf_program *prog, const char *path)
> +{
> +	struct bpf_link *link;
> +	int err;
> +
> +	link = bpf_program__attach(prog);
> +	if (!link)
> +		return -1;
> +
> +	err = bpf_link__pin(link, path);
> +	if (err) {
> +		bpf_link__destroy(link);
> +		return err;
> +	}
> +	return 0;
> +}
> +
> +static int pathname_concat(const char *path, const char *name, char *buf)
> +{
> +	int len;
> +
> +	len = snprintf(buf, PATH_MAX, "%s/%s", path, name);
> +	if (len < 0)
> +		return -EINVAL;
> +	if (len >= PATH_MAX)
> +		return -ENAMETOOLONG;
> +
> +	return 0;
> +}
> +
> +static int
> +auto_attach_programs(struct bpf_object *obj, const char *path)
> +{
> +	struct bpf_program *prog;
> +	char buf[PATH_MAX];
> +	int err;
> +
> +	bpf_object__for_each_program(prog, obj) {
> +		err = pathname_concat(path, bpf_program__name(prog), buf);
> +		if (err)
> +			goto err_unpin_programs;
> +
> +		err = auto_attach_program(prog, buf);
> +		if (err && errno != EOPNOTSUPP)
> +			goto err_unpin_programs;

If I read the above correctly, we skip entirely programs that couldn't
be auto-attached. I'm not sure what Andrii had in mind exactly, but it
would make sense to me to fallback to regular program pinning if the
program couldn't be attached/linked, so we still keep it loaded in the
kernel after bpftool exits. Probably with a p_info() message to let
users know?

> +	}
> +
> +	return 0;
> +
> +err_unpin_programs:
> +	while ((prog = bpf_object__prev_program(obj, prog))) {
> +		if (pathname_concat(path, bpf_program__name(prog), buf))
> +			continue;
> +
> +		bpf_program__unpin(prog, buf);
> +	}
> +
> +	return err;
> +}
wangyufen Sept. 27, 2022, 11:04 a.m. UTC | #2 
在 2022/9/26 18:46, Quentin Monnet 写道:
> Sat Sep 24 2022 11:13:48 GMT+0100 (British Summer Time) ~ Wang Yufen
> <wangyufen@huawei.com>
>> Add auto_attach optional to support one-step load-attach-pin_link.
>>
>> For example,
>>     $ bpftool prog loadall test.o /sys/fs/bpf/test autoattach
>>
>>     $ bpftool link
>>     26: tracing  name test1  tag f0da7d0058c00236  gpl
>>     	loaded_at 2022-09-09T21:39:49+0800  uid 0
>>     	xlated 88B  jited 55B  memlock 4096B  map_ids 3
>>     	btf_id 55
>>     28: kprobe  name test3  tag 002ef1bef0723833  gpl
>>     	loaded_at 2022-09-09T21:39:49+0800  uid 0
>>     	xlated 88B  jited 56B  memlock 4096B  map_ids 3
>>     	btf_id 55
>>     57: tracepoint  name oncpu  tag 7aa55dfbdcb78941  gpl
>>     	loaded_at 2022-09-09T21:41:32+0800  uid 0
>>     	xlated 456B  jited 265B  memlock 4096B  map_ids 17,13,14,15
>>     	btf_id 82
>>
>>     $ bpftool link
>>     1: tracing  prog 26
>>     	prog_type tracing  attach_type trace_fentry
>>     3: perf_event  prog 28
>>     10: perf_event  prog 57
>>
>> The autoattach optional can support tracepoints, k(ret)probes,
>> u(ret)probes.
>>
>> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
>> Signed-off-by: Wang Yufen <wangyufen@huawei.com>
>> ---
>> v5 -> v6: skip the programs not supporting auto-attach,
>> 	  and change optional name from "auto_attach" to "autoattach"
>> v4 -> v5: some formatting nits of doc
>> v3 -> v4: rename functions, update doc, bash and do_help()
>> v2 -> v3: switch to extend prog load command instead of extend perf
>> v2: https://patchwork.kernel.org/project/netdevbpf/patch/20220824033837.458197-1-weiyongjun1@huawei.com/
>> v1: https://patchwork.kernel.org/project/netdevbpf/patch/20220816151725.153343-1-weiyongjun1@huawei.com/
>>   tools/bpf/bpftool/prog.c | 76 ++++++++++++++++++++++++++++++++++++++--
>>   1 file changed, 74 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
>> index c81362a001ba..b1cbd06dee19 100644
>> --- a/tools/bpf/bpftool/prog.c
>> +++ b/tools/bpf/bpftool/prog.c
>> @@ -1453,6 +1453,67 @@ get_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
>>   	return ret;
>>   }
>>   
>> +static int
>> +auto_attach_program(struct bpf_program *prog, const char *path)
>> +{
>> +	struct bpf_link *link;
>> +	int err;
>> +
>> +	link = bpf_program__attach(prog);
>> +	if (!link)
>> +		return -1;
>> +
>> +	err = bpf_link__pin(link, path);
>> +	if (err) {
>> +		bpf_link__destroy(link);
>> +		return err;
>> +	}
>> +	return 0;
>> +}
>> +
>> +static int pathname_concat(const char *path, const char *name, char *buf)
>> +{
>> +	int len;
>> +
>> +	len = snprintf(buf, PATH_MAX, "%s/%s", path, name);
>> +	if (len < 0)
>> +		return -EINVAL;
>> +	if (len >= PATH_MAX)
>> +		return -ENAMETOOLONG;
>> +
>> +	return 0;
>> +}
>> +
>> +static int
>> +auto_attach_programs(struct bpf_object *obj, const char *path)
>> +{
>> +	struct bpf_program *prog;
>> +	char buf[PATH_MAX];
>> +	int err;
>> +
>> +	bpf_object__for_each_program(prog, obj) {
>> +		err = pathname_concat(path, bpf_program__name(prog), buf);
>> +		if (err)
>> +			goto err_unpin_programs;
>> +
>> +		err = auto_attach_program(prog, buf);
>> +		if (err && errno != EOPNOTSUPP)
>> +			goto err_unpin_programs;
> If I read the above correctly, we skip entirely programs that couldn't
> be auto-attached. I'm not sure what Andrii had in mind exactly, but it
> would make sense to me to fallback to regular program pinning if the
> program couldn't be attached/linked, so we still keep it loaded in the
> kernel after bpftool exits. Probably with a p_info() message to let
> users know?

Thanks for your comment.
I agree with you.
add in v7.

>
>> +	}
>> +
>> +	return 0;
>> +
>> +err_unpin_programs:
>> +	while ((prog = bpf_object__prev_program(obj, prog))) {
>> +		if (pathname_concat(path, bpf_program__name(prog), buf))
>> +			continue;
>> +
>> +		bpf_program__unpin(prog, buf);
>> +	}
>> +
>> +	return err;
>> +}
diff mbox series

Patch

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index c81362a001ba..b1cbd06dee19 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1453,6 +1453,67 @@  get_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
 	return ret;
 }
 
+static int
+auto_attach_program(struct bpf_program *prog, const char *path)
+{
+	struct bpf_link *link;
+	int err;
+
+	link = bpf_program__attach(prog);
+	if (!link)
+		return -1;
+
+	err = bpf_link__pin(link, path);
+	if (err) {
+		bpf_link__destroy(link);
+		return err;
+	}
+	return 0;
+}
+
+static int pathname_concat(const char *path, const char *name, char *buf)
+{
+	int len;
+
+	len = snprintf(buf, PATH_MAX, "%s/%s", path, name);
+	if (len < 0)
+		return -EINVAL;
+	if (len >= PATH_MAX)
+		return -ENAMETOOLONG;
+
+	return 0;
+}
+
+static int
+auto_attach_programs(struct bpf_object *obj, const char *path)
+{
+	struct bpf_program *prog;
+	char buf[PATH_MAX];
+	int err;
+
+	bpf_object__for_each_program(prog, obj) {
+		err = pathname_concat(path, bpf_program__name(prog), buf);
+		if (err)
+			goto err_unpin_programs;
+
+		err = auto_attach_program(prog, buf);
+		if (err && errno != EOPNOTSUPP)
+			goto err_unpin_programs;
+	}
+
+	return 0;
+
+err_unpin_programs:
+	while ((prog = bpf_object__prev_program(obj, prog))) {
+		if (pathname_concat(path, bpf_program__name(prog), buf))
+			continue;
+
+		bpf_program__unpin(prog, buf);
+	}
+
+	return err;
+}
+
 static int load_with_options(int argc, char **argv, bool first_prog_only)
 {
 	enum bpf_prog_type common_prog_type = BPF_PROG_TYPE_UNSPEC;
@@ -1464,6 +1525,7 @@  static int load_with_options(int argc, char **argv, bool first_prog_only)
 	struct bpf_program *prog = NULL, *pos;
 	unsigned int old_map_fds = 0;
 	const char *pinmaps = NULL;
+	bool auto_attach = false;
 	struct bpf_object *obj;
 	struct bpf_map *map;
 	const char *pinfile;
@@ -1583,6 +1645,9 @@  static int load_with_options(int argc, char **argv, bool first_prog_only)
 				goto err_free_reuse_maps;
 
 			pinmaps = GET_ARG();
+		} else if (is_prefix(*argv, "autoattach")) {
+			auto_attach = true;
+			NEXT_ARG();
 		} else {
 			p_err("expected no more arguments, 'type', 'map' or 'dev', got: '%s'?",
 			      *argv);
@@ -1692,14 +1757,20 @@  static int load_with_options(int argc, char **argv, bool first_prog_only)
 			goto err_close_obj;
 		}
 
-		err = bpf_obj_pin(bpf_program__fd(prog), pinfile);
+		if (auto_attach)
+			err = auto_attach_program(prog, pinfile);
+		else
+			err = bpf_obj_pin(bpf_program__fd(prog), pinfile);
 		if (err) {
 			p_err("failed to pin program %s",
 			      bpf_program__section_name(prog));
 			goto err_close_obj;
 		}
 	} else {
-		err = bpf_object__pin_programs(obj, pinfile);
+		if (auto_attach)
+			err = auto_attach_programs(obj, pinfile);
+		else
+			err = bpf_object__pin_programs(obj, pinfile);
 		if (err) {
 			p_err("failed to pin all programs");
 			goto err_close_obj;
@@ -2338,6 +2409,7 @@  static int do_help(int argc, char **argv)
 		"                         [type TYPE] [dev NAME] \\\n"
 		"                         [map { idx IDX | name NAME } MAP]\\\n"
 		"                         [pinmaps MAP_DIR]\n"
+		"                         [autoattach]\n"
 		"       %1$s %2$s attach PROG ATTACH_TYPE [MAP]\n"
 		"       %1$s %2$s detach PROG ATTACH_TYPE [MAP]\n"
 		"       %1$s %2$s run PROG \\\n"