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Merge branch 'BTF-map-in-map'

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Andrii Nakryiko says:

====================
This patch set teaches libbpf how to declare and initialize ARRAY_OF_MAPS and
HASH_OF_MAPS maps. See patch #3 for all the details.

Patch #1 refactors parsing BTF definition of map to re-use it cleanly for
inner map definition parsing.

Patch #2 refactors map creation and destruction logic for reuse. It also fixes
existing bug with not closing successfully created maps when bpf_object map
creation overall fails.

Patch #3 adds support for an extension of BTF-defined map syntax, as well as
parsing, recording, and use of relocations to allow declaratively initialize
outer maps with references to inner maps.

v1->v2:
  - rename __inner to __array (Alexei).
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Alexei Starovoitov 2020-04-28 17:35:03 -07:00
commit 3271e8f3f6
4 changed files with 669 additions and 281 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
tools/lib/bpf/bpf_helpers.h
View File

@ -12,6 +12,7 @@
#define __uint(name, val) int (*name)[val]
#define __type(name, val) typeof(val) *name
#define __array(name, val) typeof(val) *name[]
/* Helper macro to print out debug messages */
#define bpf_printk(fmt, ...) \

824
tools/lib/bpf/libbpf.c
View File

@ -310,6 +310,7 @@ struct bpf_map {
int map_ifindex;
int inner_map_fd;
struct bpf_map_def def;
__u32 btf_var_idx;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
__u32 btf_vmlinux_value_type_id;
@ -318,6 +319,9 @@ struct bpf_map {
enum libbpf_map_type libbpf_type;
void *mmaped;
struct bpf_struct_ops *st_ops;
struct bpf_map *inner_map;
void **init_slots;
int init_slots_sz;
char *pin_path;
bool pinned;
bool reused;
@ -389,6 +393,7 @@ struct bpf_object {
int nr_reloc_sects;
int maps_shndx;
int btf_maps_shndx;
__u32 btf_maps_sec_btf_id;
int text_shndx;
int symbols_shndx;
int data_shndx;
@ -1914,25 +1919,255 @@ static int build_map_pin_path(struct bpf_map *map, const char *path)
return 0;
}
static int parse_btf_map_def(struct bpf_object *obj,
struct bpf_map *map,
const struct btf_type *def,
bool strict, bool is_inner,
const char *pin_root_path)
{
const struct btf_type *t;
const struct btf_member *m;
int vlen, i;
vlen = btf_vlen(def);
m = btf_members(def);
for (i = 0; i < vlen; i++, m++) {
const char *name = btf__name_by_offset(obj->btf, m->name_off);
if (!name) {
pr_warn("map '%s': invalid field #%d.\n", map->name, i);
return -EINVAL;
}
if (strcmp(name, "type") == 0) {
if (!get_map_field_int(map->name, obj->btf, m,
&map->def.type))
return -EINVAL;
pr_debug("map '%s': found type = %u.\n",
map->name, map->def.type);
} else if (strcmp(name, "max_entries") == 0) {
if (!get_map_field_int(map->name, obj->btf, m,
&map->def.max_entries))
return -EINVAL;
pr_debug("map '%s': found max_entries = %u.\n",
map->name, map->def.max_entries);
} else if (strcmp(name, "map_flags") == 0) {
if (!get_map_field_int(map->name, obj->btf, m,
&map->def.map_flags))
return -EINVAL;
pr_debug("map '%s': found map_flags = %u.\n",
map->name, map->def.map_flags);
} else if (strcmp(name, "key_size") == 0) {
__u32 sz;
if (!get_map_field_int(map->name, obj->btf, m, &sz))
return -EINVAL;
pr_debug("map '%s': found key_size = %u.\n",
map->name, sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %u.\n",
map->name, map->def.key_size, sz);
return -EINVAL;
}
map->def.key_size = sz;
} else if (strcmp(name, "key") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': key type [%d] not found.\n",
map->name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': key spec is not PTR: %u.\n",
map->name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n",
map->name, t->type, (ssize_t)sz);
return sz;
}
pr_debug("map '%s': found key [%u], sz = %zd.\n",
map->name, t->type, (ssize_t)sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %zd.\n",
map->name, map->def.key_size, (ssize_t)sz);
return -EINVAL;
}
map->def.key_size = sz;
map->btf_key_type_id = t->type;
} else if (strcmp(name, "value_size") == 0) {
__u32 sz;
if (!get_map_field_int(map->name, obj->btf, m, &sz))
return -EINVAL;
pr_debug("map '%s': found value_size = %u.\n",
map->name, sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %u.\n",
map->name, map->def.value_size, sz);
return -EINVAL;
}
map->def.value_size = sz;
} else if (strcmp(name, "value") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': value type [%d] not found.\n",
map->name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': value spec is not PTR: %u.\n",
map->name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n",
map->name, t->type, (ssize_t)sz);
return sz;
}
pr_debug("map '%s': found value [%u], sz = %zd.\n",
map->name, t->type, (ssize_t)sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %zd.\n",
map->name, map->def.value_size, (ssize_t)sz);
return -EINVAL;
}
map->def.value_size = sz;
map->btf_value_type_id = t->type;
}
else if (strcmp(name, "values") == 0) {
int err;
if (is_inner) {
pr_warn("map '%s': multi-level inner maps not supported.\n",
map->name);
return -ENOTSUP;
}
if (i != vlen - 1) {
pr_warn("map '%s': '%s' member should be last.\n",
map->name, name);
return -EINVAL;
}
if (!bpf_map_type__is_map_in_map(map->def.type)) {
pr_warn("map '%s': should be map-in-map.\n",
map->name);
return -ENOTSUP;
}
if (map->def.value_size && map->def.value_size != 4) {
pr_warn("map '%s': conflicting value size %u != 4.\n",
map->name, map->def.value_size);
return -EINVAL;
}
map->def.value_size = 4;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': map-in-map inner type [%d] not found.\n",
map->name, m->type);
return -EINVAL;
}
if (!btf_is_array(t) || btf_array(t)->nelems) {
pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n",
map->name);
return -EINVAL;
}
t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type,
NULL);
if (!btf_is_ptr(t)) {
pr_warn("map '%s': map-in-map inner def is of unexpected kind %u.\n",
map->name, btf_kind(t));
return -EINVAL;
}
t = skip_mods_and_typedefs(obj->btf, t->type, NULL);
if (!btf_is_struct(t)) {
pr_warn("map '%s': map-in-map inner def is of unexpected kind %u.\n",
map->name, btf_kind(t));
return -EINVAL;
}
map->inner_map = calloc(1, sizeof(*map->inner_map));
if (!map->inner_map)
return -ENOMEM;
map->inner_map->sec_idx = obj->efile.btf_maps_shndx;
map->inner_map->name = malloc(strlen(map->name) +
sizeof(".inner") + 1);
if (!map->inner_map->name)
return -ENOMEM;
sprintf(map->inner_map->name, "%s.inner", map->name);
err = parse_btf_map_def(obj, map->inner_map, t, strict,
true /* is_inner */, NULL);
if (err)
return err;
} else if (strcmp(name, "pinning") == 0) {
__u32 val;
int err;
if (is_inner) {
pr_debug("map '%s': inner def can't be pinned.\n",
map->name);
return -EINVAL;
}
if (!get_map_field_int(map->name, obj->btf, m, &val))
return -EINVAL;
pr_debug("map '%s': found pinning = %u.\n",
map->name, val);
if (val != LIBBPF_PIN_NONE &&
val != LIBBPF_PIN_BY_NAME) {
pr_warn("map '%s': invalid pinning value %u.\n",
map->name, val);
return -EINVAL;
}
if (val == LIBBPF_PIN_BY_NAME) {
err = build_map_pin_path(map, pin_root_path);
if (err) {
pr_warn("map '%s': couldn't build pin path.\n",
map->name);
return err;
}
}
} else {
if (strict) {
pr_warn("map '%s': unknown field '%s'.\n",
map->name, name);
return -ENOTSUP;
}
pr_debug("map '%s': ignoring unknown field '%s'.\n",
map->name, name);
}
}
if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
pr_warn("map '%s': map type isn't specified.\n", map->name);
return -EINVAL;
}
return 0;
}
static int bpf_object__init_user_btf_map(struct bpf_object *obj,
const struct btf_type *sec,
int var_idx, int sec_idx,
const Elf_Data *data, bool strict,
const char *pin_root_path)
{
const struct btf_type *var, *def, *t;
const struct btf_type *var, *def;
const struct btf_var_secinfo *vi;
const struct btf_var *var_extra;
const struct btf_member *m;
const char *map_name;
struct bpf_map *map;
int vlen, i;
vi = btf_var_secinfos(sec) + var_idx;
var = btf__type_by_id(obj->btf, vi->type);
var_extra = btf_var(var);
map_name = btf__name_by_offset(obj->btf, var->name_off);
vlen = btf_vlen(var);
if (map_name == NULL || map_name[0] == '\0') {
pr_warn("map #%d: empty name.\n", var_idx);
@ -1977,160 +2212,11 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj,
map->def.type = BPF_MAP_TYPE_UNSPEC;
map->sec_idx = sec_idx;
map->sec_offset = vi->offset;
map->btf_var_idx = var_idx;
pr_debug("map '%s': at sec_idx %d, offset %zu.\n",
map_name, map->sec_idx, map->sec_offset);
vlen = btf_vlen(def);
m = btf_members(def);
for (i = 0; i < vlen; i++, m++) {
const char *name = btf__name_by_offset(obj->btf, m->name_off);
if (!name) {
pr_warn("map '%s': invalid field #%d.\n", map_name, i);
return -EINVAL;
}
if (strcmp(name, "type") == 0) {
if (!get_map_field_int(map_name, obj->btf, m,
&map->def.type))
return -EINVAL;
pr_debug("map '%s': found type = %u.\n",
map_name, map->def.type);
} else if (strcmp(name, "max_entries") == 0) {
if (!get_map_field_int(map_name, obj->btf, m,
&map->def.max_entries))
return -EINVAL;
pr_debug("map '%s': found max_entries = %u.\n",
map_name, map->def.max_entries);
} else if (strcmp(name, "map_flags") == 0) {
if (!get_map_field_int(map_name, obj->btf, m,
&map->def.map_flags))
return -EINVAL;
pr_debug("map '%s': found map_flags = %u.\n",
map_name, map->def.map_flags);
} else if (strcmp(name, "key_size") == 0) {
__u32 sz;
if (!get_map_field_int(map_name, obj->btf, m, &sz))
return -EINVAL;
pr_debug("map '%s': found key_size = %u.\n",
map_name, sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %u.\n",
map_name, map->def.key_size, sz);
return -EINVAL;
}
map->def.key_size = sz;
} else if (strcmp(name, "key") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': key type [%d] not found.\n",
map_name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': key spec is not PTR: %u.\n",
map_name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n",
map_name, t->type, (ssize_t)sz);
return sz;
}
pr_debug("map '%s': found key [%u], sz = %zd.\n",
map_name, t->type, (ssize_t)sz);
if (map->def.key_size && map->def.key_size != sz) {
pr_warn("map '%s': conflicting key size %u != %zd.\n",
map_name, map->def.key_size, (ssize_t)sz);
return -EINVAL;
}
map->def.key_size = sz;
map->btf_key_type_id = t->type;
} else if (strcmp(name, "value_size") == 0) {
__u32 sz;
if (!get_map_field_int(map_name, obj->btf, m, &sz))
return -EINVAL;
pr_debug("map '%s': found value_size = %u.\n",
map_name, sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %u.\n",
map_name, map->def.value_size, sz);
return -EINVAL;
}
map->def.value_size = sz;
} else if (strcmp(name, "value") == 0) {
__s64 sz;
t = btf__type_by_id(obj->btf, m->type);
if (!t) {
pr_warn("map '%s': value type [%d] not found.\n",
map_name, m->type);
return -EINVAL;
}
if (!btf_is_ptr(t)) {
pr_warn("map '%s': value spec is not PTR: %u.\n",
map_name, btf_kind(t));
return -EINVAL;
}
sz = btf__resolve_size(obj->btf, t->type);
if (sz < 0) {
pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n",
map_name, t->type, (ssize_t)sz);
return sz;
}
pr_debug("map '%s': found value [%u], sz = %zd.\n",
map_name, t->type, (ssize_t)sz);
if (map->def.value_size && map->def.value_size != sz) {
pr_warn("map '%s': conflicting value size %u != %zd.\n",
map_name, map->def.value_size, (ssize_t)sz);
return -EINVAL;
}
map->def.value_size = sz;
map->btf_value_type_id = t->type;
} else if (strcmp(name, "pinning") == 0) {
__u32 val;
int err;
if (!get_map_field_int(map_name, obj->btf, m, &val))
return -EINVAL;
pr_debug("map '%s': found pinning = %u.\n",
map_name, val);
if (val != LIBBPF_PIN_NONE &&
val != LIBBPF_PIN_BY_NAME) {
pr_warn("map '%s': invalid pinning value %u.\n",
map_name, val);
return -EINVAL;
}
if (val == LIBBPF_PIN_BY_NAME) {
err = build_map_pin_path(map, pin_root_path);
if (err) {
pr_warn("map '%s': couldn't build pin path.\n",
map_name);
return err;
}
}
} else {
if (strict) {
pr_warn("map '%s': unknown field '%s'.\n",
map_name, name);
return -ENOTSUP;
}
pr_debug("map '%s': ignoring unknown field '%s'.\n",
map_name, name);
}
}
if (map->def.type == BPF_MAP_TYPE_UNSPEC) {
pr_warn("map '%s': map type isn't specified.\n", map_name);
return -EINVAL;
}
return 0;
return parse_btf_map_def(obj, map, def, strict, false, pin_root_path);
}
static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
@ -2163,6 +2249,7 @@ static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict,
name = btf__name_by_offset(obj->btf, t->name_off);
if (strcmp(name, MAPS_ELF_SEC) == 0) {
sec = t;
obj->efile.btf_maps_sec_btf_id = i;
break;
}
}
@ -2549,7 +2636,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
/* Only do relo for section with exec instructions */
if (!section_have_execinstr(obj, sec) &&
strcmp(name, ".rel" STRUCT_OPS_SEC)) {
strcmp(name, ".rel" STRUCT_OPS_SEC) &&
strcmp(name, ".rel" MAPS_ELF_SEC)) {
pr_debug("skip relo %s(%d) for section(%d)\n",
name, idx, sec);
continue;
@ -3482,124 +3570,181 @@ bpf_object__populate_internal_map(struct bpf_object *obj, struct bpf_map *map)
return 0;
}
static void bpf_map__destroy(struct bpf_map *map);
static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map)
{
struct bpf_create_map_attr create_attr;
struct bpf_map_def *def = &map->def;
memset(&create_attr, 0, sizeof(create_attr));
if (obj->caps.name)
create_attr.name = map->name;
create_attr.map_ifindex = map->map_ifindex;
create_attr.map_type = def->type;
create_attr.map_flags = def->map_flags;
create_attr.key_size = def->key_size;
create_attr.value_size = def->value_size;
if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !def->max_entries) {
int nr_cpus;
nr_cpus = libbpf_num_possible_cpus();
if (nr_cpus < 0) {
pr_warn("map '%s': failed to determine number of system CPUs: %d\n",
map->name, nr_cpus);
return nr_cpus;
}
pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus);
create_attr.max_entries = nr_cpus;
} else {
create_attr.max_entries = def->max_entries;
}
if (bpf_map__is_struct_ops(map))
create_attr.btf_vmlinux_value_type_id =
map->btf_vmlinux_value_type_id;
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
if (obj->btf && !bpf_map_find_btf_info(obj, map)) {
create_attr.btf_fd = btf__fd(obj->btf);
create_attr.btf_key_type_id = map->btf_key_type_id;
create_attr.btf_value_type_id = map->btf_value_type_id;
}
if (bpf_map_type__is_map_in_map(def->type)) {
if (map->inner_map) {
int err;
err = bpf_object__create_map(obj, map->inner_map);
if (err) {
pr_warn("map '%s': failed to create inner map: %d\n",
map->name, err);
return err;
}
map->inner_map_fd = bpf_map__fd(map->inner_map);
}
if (map->inner_map_fd >= 0)
create_attr.inner_map_fd = map->inner_map_fd;
}
map->fd = bpf_create_map_xattr(&create_attr);
if (map->fd < 0 && (create_attr.btf_key_type_id ||
create_attr.btf_value_type_id)) {
char *cp, errmsg[STRERR_BUFSIZE];
int err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
map->name, cp, err);
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
map->btf_key_type_id = 0;
map->btf_value_type_id = 0;
map->fd = bpf_create_map_xattr(&create_attr);
}
if (map->fd < 0)
return -errno;
if (bpf_map_type__is_map_in_map(def->type) && map->inner_map) {
bpf_map__destroy(map->inner_map);
zfree(&map->inner_map);
}
return 0;
}
static int
bpf_object__create_maps(struct bpf_object *obj)
{
struct bpf_create_map_attr create_attr = {};
int nr_cpus = 0;
unsigned int i;
struct bpf_map *map;
char *cp, errmsg[STRERR_BUFSIZE];
unsigned int i, j;
int err;
for (i = 0; i < obj->nr_maps; i++) {
struct bpf_map *map = &obj->maps[i];
struct bpf_map_def *def = &map->def;
char *cp, errmsg[STRERR_BUFSIZE];
int *pfd = &map->fd;
map = &obj->maps[i];
if (map->pin_path) {
err = bpf_object__reuse_map(map);
if (err) {
pr_warn("error reusing pinned map %s\n",
pr_warn("map '%s': error reusing pinned map\n",
map->name);
return err;
goto err_out;
}
}
if (map->fd >= 0) {
pr_debug("skip map create (preset) %s: fd=%d\n",
pr_debug("map '%s': skipping creation (preset fd=%d)\n",
map->name, map->fd);
continue;
}
if (obj->caps.name)
create_attr.name = map->name;
create_attr.map_ifindex = map->map_ifindex;
create_attr.map_type = def->type;
create_attr.map_flags = def->map_flags;
create_attr.key_size = def->key_size;
create_attr.value_size = def->value_size;
if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY &&
!def->max_entries) {
if (!nr_cpus)
nr_cpus = libbpf_num_possible_cpus();
if (nr_cpus < 0) {
pr_warn("failed to determine number of system CPUs: %d\n",
nr_cpus);
err = nr_cpus;
goto err_out;
}
pr_debug("map '%s': setting size to %d\n",
map->name, nr_cpus);
create_attr.max_entries = nr_cpus;
} else {
create_attr.max_entries = def->max_entries;
}
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
if (bpf_map_type__is_map_in_map(def->type) &&
map->inner_map_fd >= 0)
create_attr.inner_map_fd = map->inner_map_fd;
if (bpf_map__is_struct_ops(map))
create_attr.btf_vmlinux_value_type_id =
map->btf_vmlinux_value_type_id;
err = bpf_object__create_map(obj, map);
if (err)
goto err_out;
if (obj->btf && !bpf_map_find_btf_info(obj, map)) {
create_attr.btf_fd = btf__fd(obj->btf);
create_attr.btf_key_type_id = map->btf_key_type_id;
create_attr.btf_value_type_id = map->btf_value_type_id;
}
*pfd = bpf_create_map_xattr(&create_attr);
if (*pfd < 0 && (create_attr.btf_key_type_id ||
create_attr.btf_value_type_id)) {
err = -errno;
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("Error in bpf_create_map_xattr(%s):%s(%d). Retrying without BTF.\n",
map->name, cp, err);
create_attr.btf_fd = 0;
create_attr.btf_key_type_id = 0;
create_attr.btf_value_type_id = 0;
map->btf_key_type_id = 0;
map->btf_value_type_id = 0;
*pfd = bpf_create_map_xattr(&create_attr);
}
if (*pfd < 0) {
size_t j;
err = -errno;
err_out:
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("failed to create map (name: '%s'): %s(%d)\n",
map->name, cp, err);
pr_perm_msg(err);
for (j = 0; j < i; j++)
zclose(obj->maps[j].fd);
return err;
}
pr_debug("map '%s': created successfully, fd=%d\n", map->name,
map->fd);
if (bpf_map__is_internal(map)) {
err = bpf_object__populate_internal_map(obj, map);
if (err < 0) {
zclose(*pfd);
zclose(map->fd);
goto err_out;
}
}
if (map->init_slots_sz) {
for (j = 0; j < map->init_slots_sz; j++) {
const struct bpf_map *targ_map;
int fd;
if (!map->init_slots[j])
continue;
targ_map = map->init_slots[j];
fd = bpf_map__fd(targ_map);
err = bpf_map_update_elem(map->fd, &j, &fd, 0);
if (err) {
err = -errno;
pr_warn("map '%s': failed to initialize slot [%d] to map '%s' fd=%d: %d\n",
map->name, j, targ_map->name,
fd, err);
goto err_out;
}
pr_debug("map '%s': slot [%d] set to map '%s' fd=%d\n",
map->name, j, targ_map->name, fd);
}
zfree(&map->init_slots);
map->init_slots_sz = 0;
}
if (map->pin_path && !map->pinned) {
err = bpf_map__pin(map, NULL);
if (err) {
pr_warn("failed to auto-pin map name '%s' at '%s'\n",
map->name, map->pin_path);
return err;
pr_warn("map '%s': failed to auto-pin at '%s': %d\n",
map->name, map->pin_path, err);
zclose(map->fd);
goto err_out;
}
}
pr_debug("created map %s: fd=%d\n", map->name, *pfd);
}
return 0;
err_out:
cp = libbpf_strerror_r(err, errmsg, sizeof(errmsg));
pr_warn("map '%s': failed to create: %s(%d)\n", map->name, cp, err);
pr_perm_msg(err);
for (j = 0; j < i; j++)
zclose(obj->maps[j].fd);
return err;
}
static int
@ -4851,9 +4996,118 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
return 0;
}
static int bpf_object__collect_struct_ops_map_reloc(struct bpf_object *obj,
GElf_Shdr *shdr,
Elf_Data *data);
static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
GElf_Shdr *shdr, Elf_Data *data);
static int bpf_object__collect_map_relos(struct bpf_object *obj,
GElf_Shdr *shdr, Elf_Data *data)
{
int i, j, nrels, new_sz, ptr_sz = sizeof(void *);
const struct btf_type *sec, *var, *def;
const struct btf_var_secinfo *vi;
const struct btf_member *member;
struct bpf_map *map, *targ_map;
const char *name, *mname;
Elf_Data *symbols;
unsigned int moff;
GElf_Sym sym;
GElf_Rel rel;
void *tmp;
if (!obj->efile.btf_maps_sec_btf_id || !obj->btf)
return -EINVAL;
sec = btf__type_by_id(obj->btf, obj->efile.btf_maps_sec_btf_id);
if (!sec)
return -EINVAL;
symbols = obj->efile.symbols;
nrels = shdr->sh_size / shdr->sh_entsize;
for (i = 0; i < nrels; i++) {
if (!gelf_getrel(data, i, &rel)) {
pr_warn(".maps relo #%d: failed to get ELF relo\n", i);
return -LIBBPF_ERRNO__FORMAT;
}
if (!gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym)) {
pr_warn(".maps relo #%d: symbol %zx not found\n",
i, (size_t)GELF_R_SYM(rel.r_info));
return -LIBBPF_ERRNO__FORMAT;
}
name = elf_strptr(obj->efile.elf, obj->efile.strtabidx,
sym.st_name) ? : "<?>";
if (sym.st_shndx != obj->efile.btf_maps_shndx) {
pr_warn(".maps relo #%d: '%s' isn't a BTF-defined map\n",
i, name);
return -LIBBPF_ERRNO__RELOC;
}
pr_debug(".maps relo #%d: for %zd value %zd rel.r_offset %zu name %d ('%s')\n",
i, (ssize_t)(rel.r_info >> 32), (size_t)sym.st_value,
(size_t)rel.r_offset, sym.st_name, name);
for (j = 0; j < obj->nr_maps; j++) {
map = &obj->maps[j];
if (map->sec_idx != obj->efile.btf_maps_shndx)
continue;
vi = btf_var_secinfos(sec) + map->btf_var_idx;
if (vi->offset <= rel.r_offset &&
rel.r_offset + sizeof(void *) <= vi->offset + vi->size)
break;
}
if (j == obj->nr_maps) {
pr_warn(".maps relo #%d: cannot find map '%s' at rel.r_offset %zu\n",
i, name, (size_t)rel.r_offset);
return -EINVAL;
}
if (!bpf_map_type__is_map_in_map(map->def.type))
return -EINVAL;
if (map->def.type == BPF_MAP_TYPE_HASH_OF_MAPS &&
map->def.key_size != sizeof(int)) {
pr_warn(".maps relo #%d: hash-of-maps '%s' should have key size %zu.\n",
i, map->name, sizeof(int));
return -EINVAL;
}
targ_map = bpf_object__find_map_by_name(obj, name);
if (!targ_map)
return -ESRCH;
var = btf__type_by_id(obj->btf, vi->type);
def = skip_mods_and_typedefs(obj->btf, var->type, NULL);
if (btf_vlen(def) == 0)
return -EINVAL;
member = btf_members(def) + btf_vlen(def) - 1;
mname = btf__name_by_offset(obj->btf, member->name_off);
if (strcmp(mname, "values"))
return -EINVAL;
moff = btf_member_bit_offset(def, btf_vlen(def) - 1) / 8;
if (rel.r_offset - vi->offset < moff)
return -EINVAL;
moff = rel.r_offset - vi->offset - moff;
if (moff % ptr_sz)
return -EINVAL;
moff /= ptr_sz;
if (moff >= map->init_slots_sz) {
new_sz = moff + 1;
tmp = realloc(map->init_slots, new_sz * ptr_sz);
if (!tmp)
return -ENOMEM;
map->init_slots = tmp;
memset(map->init_slots + map->init_slots_sz, 0,
(new_sz - map->init_slots_sz) * ptr_sz);
map->init_slots_sz = new_sz;
}
map->init_slots[moff] = targ_map;
pr_debug(".maps relo #%d: map '%s' slot [%d] points to map '%s'\n",
i, map->name, moff, name);
}
return 0;
}
static int bpf_object__collect_reloc(struct bpf_object *obj)
{
@ -4876,21 +5130,17 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
}
if (idx == obj->efile.st_ops_shndx) {
err = bpf_object__collect_struct_ops_map_reloc(obj,
shdr,
data);
if (err)
return err;
continue;
err = bpf_object__collect_st_ops_relos(obj, shdr, data);
} else if (idx == obj->efile.btf_maps_shndx) {
err = bpf_object__collect_map_relos(obj, shdr, data);
} else {
prog = bpf_object__find_prog_by_idx(obj, idx);
if (!prog) {
pr_warn("relocation failed: no prog in section(%d)\n", idx);
return -LIBBPF_ERRNO__RELOC;
}
err = bpf_program__collect_reloc(prog, shdr, data, obj);
}
prog = bpf_object__find_prog_by_idx(obj, idx);
if (!prog) {
pr_warn("relocation failed: no section(%d)\n", idx);
return -LIBBPF_ERRNO__RELOC;
}
err = bpf_program__collect_reloc(prog, shdr, data, obj);
if (err)
return err;
}
@ -5955,6 +6205,40 @@ int bpf_object__pin(struct bpf_object *obj, const char *path)
return 0;
}
static void bpf_map__destroy(struct bpf_map *map)
{
if (map->clear_priv)
map->clear_priv(map, map->priv);
map->priv = NULL;
map->clear_priv = NULL;
if (map->inner_map) {
bpf_map__destroy(map->inner_map);
zfree(&map->inner_map);
}
zfree(&map->init_slots);
map->init_slots_sz = 0;
if (map->mmaped) {
munmap(map->mmaped, bpf_map_mmap_sz(map));
map->mmaped = NULL;
}
if (map->st_ops) {
zfree(&map->st_ops->data);
zfree(&map->st_ops->progs);
zfree(&map->st_ops->kern_func_off);
zfree(&map->st_ops);
}
zfree(&map->name);
zfree(&map->pin_path);
if (map->fd >= 0)
zclose(map->fd);
}
void bpf_object__close(struct bpf_object *obj)
{
size_t i;
@ -5970,29 +6254,8 @@ void bpf_object__close(struct bpf_object *obj)
btf__free(obj->btf);
btf_ext__free(obj->btf_ext);
for (i = 0; i < obj->nr_maps; i++) {
struct bpf_map *map = &obj->maps[i];
if (map->clear_priv)
map->clear_priv(map, map->priv);
map->priv = NULL;
map->clear_priv = NULL;
if (map->mmaped) {
munmap(map->mmaped, bpf_map_mmap_sz(map));
map->mmaped = NULL;
}
if (map->st_ops) {
zfree(&map->st_ops->data);
zfree(&map->st_ops->progs);
zfree(&map->st_ops->kern_func_off);
zfree(&map->st_ops);
}
zfree(&map->name);
zfree(&map->pin_path);
}
for (i = 0; i < obj->nr_maps; i++)
bpf_map__destroy(&obj->maps[i]);
zfree(&obj->kconfig);
zfree(&obj->externs);
@ -6516,9 +6779,8 @@ static struct bpf_map *find_struct_ops_map_by_offset(struct bpf_object *obj,
}
/* Collect the reloc from ELF and populate the st_ops->progs[] */
static int bpf_object__collect_struct_ops_map_reloc(struct bpf_object *obj,
GElf_Shdr *shdr,
Elf_Data *data)
static int bpf_object__collect_st_ops_relos(struct bpf_object *obj,
GElf_Shdr *shdr, Elf_Data *data)
{
const struct btf_member *member;
struct bpf_struct_ops *st_ops;

49
tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c Normal file
View File

@ -0,0 +1,49 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <test_progs.h>
#include "test_btf_map_in_map.skel.h"
void test_btf_map_in_map(void)
{
int duration = 0, err, key = 0, val;
struct test_btf_map_in_map* skel;
skel = test_btf_map_in_map__open_and_load();
if (CHECK(!skel, "skel_open", "failed to open&load skeleton\n"))
return;
err = test_btf_map_in_map__attach(skel);
if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
goto cleanup;
/* inner1 = input, inner2 = input + 1 */
val = bpf_map__fd(skel->maps.inner_map1);
bpf_map_update_elem(bpf_map__fd(skel->maps.outer_arr), &key, &val, 0);
val = bpf_map__fd(skel->maps.inner_map2);
bpf_map_update_elem(bpf_map__fd(skel->maps.outer_hash), &key, &val, 0);
skel->bss->input = 1;
usleep(1);
bpf_map_lookup_elem(bpf_map__fd(skel->maps.inner_map1), &key, &val);
CHECK(val != 1, "inner1", "got %d != exp %d\n", val, 1);
bpf_map_lookup_elem(bpf_map__fd(skel->maps.inner_map2), &key, &val);
CHECK(val != 2, "inner2", "got %d != exp %d\n", val, 2);
/* inner1 = input + 1, inner2 = input */
val = bpf_map__fd(skel->maps.inner_map2);
bpf_map_update_elem(bpf_map__fd(skel->maps.outer_arr), &key, &val, 0);
val = bpf_map__fd(skel->maps.inner_map1);
bpf_map_update_elem(bpf_map__fd(skel->maps.outer_hash), &key, &val, 0);
skel->bss->input = 3;
usleep(1);
bpf_map_lookup_elem(bpf_map__fd(skel->maps.inner_map1), &key, &val);
CHECK(val != 4, "inner1", "got %d != exp %d\n", val, 4);
bpf_map_lookup_elem(bpf_map__fd(skel->maps.inner_map2), &key, &val);
CHECK(val != 3, "inner2", "got %d != exp %d\n", val, 3);
cleanup:
test_btf_map_in_map__destroy(skel);
}

76
tools/testing/selftests/bpf/progs/test_btf_map_in_map.c Normal file
View File

@ -0,0 +1,76 @@
/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (c) 2020 Facebook */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
struct inner_map {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, int);
} inner_map1 SEC(".maps"),
inner_map2 SEC(".maps");
struct outer_arr {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(max_entries, 3);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(int));
/* it's possible to use anonymous struct as inner map definition here */
__array(values, struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
/* changing max_entries to 2 will fail during load
* due to incompatibility with inner_map definition */
__uint(max_entries, 1);
__type(key, int);
__type(value, int);
});
} outer_arr SEC(".maps") = {
/* (void *) cast is necessary because we didn't use `struct inner_map`
* in __inner(values, ...)
* Actually, a conscious effort is required to screw up initialization
* of inner map slots, which is a great thing!
*/
.values = { (void *)&inner_map1, 0, (void *)&inner_map2 },
};
struct outer_hash {
__uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
__uint(max_entries, 5);
__uint(key_size, sizeof(int));
/* Here everything works flawlessly due to reuse of struct inner_map
* and compiler will complain at the attempt to use non-inner_map
* references below. This is great experience.
*/
__array(values, struct inner_map);
} outer_hash SEC(".maps") = {
.values = {
[0] = &inner_map2,
[4] = &inner_map1,
},
};
int input = 0;
SEC("raw_tp/sys_enter")
int handle__sys_enter(void *ctx)
{
struct inner_map *inner_map;
int key = 0, val;
inner_map = bpf_map_lookup_elem(&outer_arr, &key);
if (!inner_map)
return 1;
val = input;
bpf_map_update_elem(inner_map, &key, &val, 0);
inner_map = bpf_map_lookup_elem(&outer_hash, &key);
if (!inner_map)
return 1;
val = input + 1;
bpf_map_update_elem(inner_map, &key, &val, 0);
return 0;
}
char _license[] SEC("license") = "GPL";