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Subject[PATCHv3 perf/core 3/6] tools lib bpf: Add bpf_object__pin()
Date
Add a new API to pin a BPF object to the filesystem. The user can
specify the path within a BPF filesystem to pin the object.
Programs will be pinned under a subdirectory named the same as the
program, with each instance appearing as a numbered file under that
directory, and maps will be pinned under the path using the name of
the map as the file basename.

For example, with the directory '/sys/fs/bpf/foo' and a BPF object which
contains two instances of a program named 'bar', and a map named 'baz':
/sys/fs/bpf/foo/bar/0
/sys/fs/bpf/foo/bar/1
/sys/fs/bpf/foo/baz

Signed-off-by: Joe Stringer <joe@ovn.org>
---
v3: Mount to PATH/MAPNAME, PATH/PROGNAME/N (N = instance number)
v2: Don't automount BPF filesystem
Split program, map, object pinning into separate APIs and separate
patches.
---
tools/lib/bpf/libbpf.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 1 +
2 files changed, 55 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ce987c02363e..703cfa986b34 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -36,6 +36,7 @@
#include <linux/magic.h>
#include <linux/list.h>
#include <linux/limits.h>
+#include <sys/stat.h>
#include <sys/vfs.h>
#include <libelf.h>
#include <gelf.h>
@@ -1371,6 +1372,59 @@ int bpf_map__pin(struct bpf_map *map, const char *path)
return 0;
}

+int bpf_object__pin(struct bpf_object *obj, const char *path)
+{
+ struct bpf_program *prog;
+ struct bpf_map *map;
+ int err;
+
+ if (!obj)
+ return -ENOENT;
+
+ if (!obj->loaded) {
+ pr_warning("object not yet loaded; load it first\n");
+ return -ENOENT;
+ }
+
+ err = make_dir(path);
+ if (err)
+ return err;
+
+ bpf_map__for_each(map, obj) {
+ char buf[PATH_MAX];
+ int len;
+
+ len = snprintf(buf, PATH_MAX, "%s/%s", path,
+ bpf_map__name(map));
+ if (len < 0)
+ return -EINVAL;
+ else if (len > PATH_MAX)
+ return -ENAMETOOLONG;
+
+ err = bpf_map__pin(map, buf);
+ if (err)
+ return err;
+ }
+
+ bpf_object__for_each_program(prog, obj) {
+ char buf[PATH_MAX];
+ int len;
+
+ len = snprintf(buf, PATH_MAX, "%s/%s", path,
+ prog->section_name);
+ if (len < 0)
+ return -EINVAL;
+ else if (len > PATH_MAX)
+ return -ENAMETOOLONG;
+
+ err = bpf_program__pin(prog, buf);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
void bpf_object__close(struct bpf_object *obj)
{
size_t i;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 2addf9d5b13c..b30394f9947a 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -65,6 +65,7 @@ struct bpf_object *bpf_object__open(const char *path);
struct bpf_object *bpf_object__open_buffer(void *obj_buf,
size_t obj_buf_sz,
const char *name);
+int bpf_object__pin(struct bpf_object *object, const char *path);
void bpf_object__close(struct bpf_object *object);

/* Load/unload object into/from kernel */
--
2.11.0
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