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Date: Sat, 02 Nov 2019 12:09:38 +0100
From: Toke Høiland-Jørgensen <toke@...hat.com>
To: Daniel Borkmann <daniel@...earbox.net>
Cc: Alexei Starovoitov <ast@...nel.org>,
Martin KaFai Lau <kafai@...com>,
Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Andrii Nakryiko <andrii.nakryiko@...il.com>,
David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
bpf@...r.kernel.org
Subject: [PATCH bpf-next v6 2/5] libbpf: Store map pin path and status in
struct bpf_map
From: Toke Høiland-Jørgensen <toke@...hat.com>
Support storing and setting a pin path in struct bpf_map, which can be used
for automatic pinning. Also store the pin status so we can avoid attempts
to re-pin a map that has already been pinned (or reused from a previous
pinning).
The behaviour of bpf_object__{un,}pin_maps() is changed so that if it is
called with a NULL path argument (which was previously illegal), it will
(un)pin only those maps that have a pin_path set.
Acked-by: Andrii Nakryiko <andriin@...com>
Signed-off-by: Toke Høiland-Jørgensen <toke@...hat.com>
---
tools/lib/bpf/libbpf.c | 164 +++++++++++++++++++++++++++++++++++-----------
tools/lib/bpf/libbpf.h | 8 ++
tools/lib/bpf/libbpf.map | 3 +
3 files changed, 134 insertions(+), 41 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ce5ef3ddd263..15a7950c3522 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -226,6 +226,8 @@ struct bpf_map {
void *priv;
bpf_map_clear_priv_t clear_priv;
enum libbpf_map_type libbpf_type;
+ char *pin_path;
+ bool pinned;
};
struct bpf_secdata {
@@ -4025,47 +4027,119 @@ int bpf_map__pin(struct bpf_map *map, const char *path)
char *cp, errmsg[STRERR_BUFSIZE];
int err;
- err = check_path(path);
- if (err)
- return err;
-
if (map == NULL) {
pr_warn("invalid map pointer\n");
return -EINVAL;
}
- if (bpf_obj_pin(map->fd, path)) {
- cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
- pr_warn("failed to pin map: %s\n", cp);
- return -errno;
+ if (map->pin_path) {
+ if (path && strcmp(path, map->pin_path)) {
+ pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
+ bpf_map__name(map), map->pin_path, path);
+ return -EINVAL;
+ } else if (map->pinned) {
+ pr_debug("map '%s' already pinned at '%s'; not re-pinning\n",
+ bpf_map__name(map), map->pin_path);
+ return 0;
+ }
+ } else {
+ if (!path) {
+ pr_warn("missing a path to pin map '%s' at\n",
+ bpf_map__name(map));
+ return -EINVAL;
+ } else if (map->pinned) {
+ pr_warn("map '%s' already pinned\n", bpf_map__name(map));
+ return -EEXIST;
+ }
+
+ map->pin_path = strdup(path);
+ if (!map->pin_path) {
+ err = -errno;
+ goto out_err;
+ }
}
- pr_debug("pinned map '%s'\n", path);
+ err = check_path(map->pin_path);
+ if (err)
+ return err;
+
+ if (bpf_obj_pin(map->fd, map->pin_path)) {
+ err = -errno;
+ goto out_err;
+ }
+
+ map->pinned = true;
+ pr_debug("pinned map '%s'\n", map->pin_path);
return 0;
+
+out_err:
+ cp = libbpf_strerror_r(-err, errmsg, sizeof(errmsg));
+ pr_warn("failed to pin map: %s\n", cp);
+ return err;
}
int bpf_map__unpin(struct bpf_map *map, const char *path)
{
int err;
- err = check_path(path);
- if (err)
- return err;
-
if (map == NULL) {
pr_warn("invalid map pointer\n");
return -EINVAL;
}
+ if (map->pin_path) {
+ if (path && strcmp(path, map->pin_path)) {
+ pr_warn("map '%s' already has pin path '%s' different from '%s'\n",
+ bpf_map__name(map), map->pin_path, path);
+ return -EINVAL;
+ }
+ path = map->pin_path;
+ } else if (!path) {
+ pr_warn("no path to unpin map '%s' from\n",
+ bpf_map__name(map));
+ return -EINVAL;
+ }
+
+ err = check_path(path);
+ if (err)
+ return err;
+
err = unlink(path);
if (err != 0)
return -errno;
- pr_debug("unpinned map '%s'\n", path);
+
+ map->pinned = false;
+ pr_debug("unpinned map '%s' from '%s'\n", bpf_map__name(map), path);
return 0;
}
+int bpf_map__set_pin_path(struct bpf_map *map, const char *path)
+{
+ char *new = NULL;
+
+ if (path) {
+ new = strdup(path);
+ if (!new)
+ return -errno;
+ }
+
+ free(map->pin_path);
+ map->pin_path = new;
+ return 0;
+}
+
+const char *bpf_map__get_pin_path(const struct bpf_map *map)
+{
+ return map->pin_path;
+}
+
+bool bpf_map__is_pinned(const struct bpf_map *map)
+{
+ return map->pinned;
+}
+
int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
{
struct bpf_map *map;
@@ -4084,20 +4158,27 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
return err;
bpf_object__for_each_map(map, obj) {
+ char *pin_path = NULL;
char buf[PATH_MAX];
- int len;
- len = snprintf(buf, PATH_MAX, "%s/%s", path,
- bpf_map__name(map));
- if (len < 0) {
- err = -EINVAL;
- goto err_unpin_maps;
- } else if (len >= PATH_MAX) {
- err = -ENAMETOOLONG;
- goto err_unpin_maps;
+ if (path) {
+ int len;
+
+ len = snprintf(buf, PATH_MAX, "%s/%s", path,
+ bpf_map__name(map));
+ if (len < 0) {
+ err = -EINVAL;
+ goto err_unpin_maps;
+ } else if (len >= PATH_MAX) {
+ err = -ENAMETOOLONG;
+ goto err_unpin_maps;
+ }
+ pin_path = buf;
+ } else if (!map->pin_path) {
+ continue;
}
- err = bpf_map__pin(map, buf);
+ err = bpf_map__pin(map, pin_path);
if (err)
goto err_unpin_maps;
}
@@ -4106,17 +4187,10 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path)
err_unpin_maps:
while ((map = bpf_map__prev(map, obj))) {
- char buf[PATH_MAX];
- int len;
-
- len = snprintf(buf, PATH_MAX, "%s/%s", path,
- bpf_map__name(map));
- if (len < 0)
- continue;
- else if (len >= PATH_MAX)
+ if (!map->pin_path)
continue;
- bpf_map__unpin(map, buf);
+ bpf_map__unpin(map, NULL);
}
return err;
@@ -4131,17 +4205,24 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path)
return -ENOENT;
bpf_object__for_each_map(map, obj) {
+ char *pin_path = NULL;
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;
+ if (path) {
+ 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;
+ pin_path = buf;
+ } else if (!map->pin_path) {
+ continue;
+ }
- err = bpf_map__unpin(map, buf);
+ err = bpf_map__unpin(map, pin_path);
if (err)
return err;
}
@@ -4266,6 +4347,7 @@ void bpf_object__close(struct bpf_object *obj)
for (i = 0; i < obj->nr_maps; i++) {
zfree(&obj->maps[i].name);
+ zfree(&obj->maps[i].pin_path);
if (obj->maps[i].clear_priv)
obj->maps[i].clear_priv(&obj->maps[i],
obj->maps[i].priv);
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index c63e2ff84abc..2ed3bbd6fcba 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -124,6 +124,11 @@ int bpf_object__section_size(const struct bpf_object *obj, const char *name,
__u32 *size);
int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
__u32 *off);
+
+/* pin_maps and unpin_maps can both be called with a NULL path, in which case
+ * they will use the pin_path attribute of each map (and ignore all maps that
+ * don't have a pin_path set).
+ */
LIBBPF_API int bpf_object__pin_maps(struct bpf_object *obj, const char *path);
LIBBPF_API int bpf_object__unpin_maps(struct bpf_object *obj,
const char *path);
@@ -385,6 +390,9 @@ LIBBPF_API int bpf_map__resize(struct bpf_map *map, __u32 max_entries);
LIBBPF_API bool bpf_map__is_offload_neutral(const struct bpf_map *map);
LIBBPF_API bool bpf_map__is_internal(const struct bpf_map *map);
LIBBPF_API void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex);
+LIBBPF_API int bpf_map__set_pin_path(struct bpf_map *map, const char *path);
+LIBBPF_API const char *bpf_map__get_pin_path(const struct bpf_map *map);
+LIBBPF_API bool bpf_map__is_pinned(const struct bpf_map *map);
LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path);
LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index d1473ea4d7a5..1681a9ce109f 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -193,6 +193,9 @@ LIBBPF_0.0.5 {
LIBBPF_0.0.6 {
global:
+ bpf_map__get_pin_path;
+ bpf_map__is_pinned;
+ bpf_map__set_pin_path;
bpf_object__open_file;
bpf_object__open_mem;
bpf_program__get_expected_attach_type;
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