Commit bd513cd0 authored by Mauricio Vasquez B's avatar Mauricio Vasquez B Committed by Alexei Starovoitov

bpf: add MAP_LOOKUP_AND_DELETE_ELEM syscall

The previous patch implemented a bpf queue/stack maps that
provided the peek/pop/push functions.  There is not a direct
relationship between those functions and the current maps
syscalls, hence a new MAP_LOOKUP_AND_DELETE_ELEM syscall is added,
this is mapped to the pop operation in the queue/stack maps
and it is still to implement in other kind of maps.
Signed-off-by: default avatarMauricio Vasquez B <mauricio.vasquez@polito.it>
Acked-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f1a2e44a
...@@ -103,6 +103,7 @@ enum bpf_cmd { ...@@ -103,6 +103,7 @@ enum bpf_cmd {
BPF_BTF_LOAD, BPF_BTF_LOAD,
BPF_BTF_GET_FD_BY_ID, BPF_BTF_GET_FD_BY_ID,
BPF_TASK_FD_QUERY, BPF_TASK_FD_QUERY,
BPF_MAP_LOOKUP_AND_DELETE_ELEM,
}; };
enum bpf_map_type { enum bpf_map_type {
......
...@@ -999,6 +999,69 @@ static int map_get_next_key(union bpf_attr *attr) ...@@ -999,6 +999,69 @@ static int map_get_next_key(union bpf_attr *attr)
return err; return err;
} }
#define BPF_MAP_LOOKUP_AND_DELETE_ELEM_LAST_FIELD value
static int map_lookup_and_delete_elem(union bpf_attr *attr)
{
void __user *ukey = u64_to_user_ptr(attr->key);
void __user *uvalue = u64_to_user_ptr(attr->value);
int ufd = attr->map_fd;
struct bpf_map *map;
void *key, *value, *ptr;
u32 value_size;
struct fd f;
int err;
if (CHECK_ATTR(BPF_MAP_LOOKUP_AND_DELETE_ELEM))
return -EINVAL;
f = fdget(ufd);
map = __bpf_map_get(f);
if (IS_ERR(map))
return PTR_ERR(map);
if (!(f.file->f_mode & FMODE_CAN_WRITE)) {
err = -EPERM;
goto err_put;
}
key = __bpf_copy_key(ukey, map->key_size);
if (IS_ERR(key)) {
err = PTR_ERR(key);
goto err_put;
}
value_size = map->value_size;
err = -ENOMEM;
value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
if (!value)
goto free_key;
if (map->map_type == BPF_MAP_TYPE_QUEUE ||
map->map_type == BPF_MAP_TYPE_STACK) {
err = map->ops->map_pop_elem(map, value);
} else {
err = -ENOTSUPP;
}
if (err)
goto free_value;
if (copy_to_user(uvalue, value, value_size) != 0)
goto free_value;
err = 0;
free_value:
kfree(value);
free_key:
kfree(key);
err_put:
fdput(f);
return err;
}
static const struct bpf_prog_ops * const bpf_prog_types[] = { static const struct bpf_prog_ops * const bpf_prog_types[] = {
#define BPF_PROG_TYPE(_id, _name) \ #define BPF_PROG_TYPE(_id, _name) \
[_id] = & _name ## _prog_ops, [_id] = & _name ## _prog_ops,
...@@ -2472,6 +2535,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz ...@@ -2472,6 +2535,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
case BPF_TASK_FD_QUERY: case BPF_TASK_FD_QUERY:
err = bpf_task_fd_query(&attr, uattr); err = bpf_task_fd_query(&attr, uattr);
break; break;
case BPF_MAP_LOOKUP_AND_DELETE_ELEM:
err = map_lookup_and_delete_elem(&attr);
break;
default: default:
err = -EINVAL; err = -EINVAL;
break; break;
......
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