On Mon, Oct 9, 2017 at 4:07 PM, Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
> On Mon, Oct 09, 2017 at 03:20:24PM -0700, Chenbo Feng wrote:
>> From: Chenbo Feng <fengc@xxxxxxxxxx>
>>
>> Introduce the map read/write flags to the eBPF syscalls that returns the
>> map fd. The flags is used to set up the file mode when construct a new
>> file descriptor for bpf maps. To not break the backward capability, the
>> f_flags is set to O_RDWR if the flag passed by syscall is 0. Otherwise
>> it should be O_RDONLY or O_WRONLY. When the userspace want to modify or
>> read the map content, it will check the file mode to see if it is
>> allowed to make the change.
>>
>> Signed-off-by: Chenbo Feng <fengc@xxxxxxxxxx>
>> Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
>> ---
>> include/linux/bpf.h | 6 ++--
>> include/uapi/linux/bpf.h | 6 ++++
>> kernel/bpf/arraymap.c | 7 +++--
>> kernel/bpf/devmap.c | 5 ++-
>> kernel/bpf/hashtab.c | 5 +--
>> kernel/bpf/inode.c | 15 ++++++---
>> kernel/bpf/lpm_trie.c | 3 +-
>> kernel/bpf/sockmap.c | 5 ++-
>> kernel/bpf/stackmap.c | 5 ++-
>> kernel/bpf/syscall.c | 80 +++++++++++++++++++++++++++++++++++++++++++-----
>> 10 files changed, 114 insertions(+), 23 deletions(-)
>>
>> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
>> index bc7da2ddfcaf..0e9ca2555d7f 100644
>> --- a/include/linux/bpf.h
>> +++ b/include/linux/bpf.h
>> @@ -308,11 +308,11 @@ void bpf_map_area_free(void *base);
>>
>> extern int sysctl_unprivileged_bpf_disabled;
>>
>> -int bpf_map_new_fd(struct bpf_map *map);
>> +int bpf_map_new_fd(struct bpf_map *map, int flags);
>> int bpf_prog_new_fd(struct bpf_prog *prog);
>>
>> int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
>> -int bpf_obj_get_user(const char __user *pathname);
>> +int bpf_obj_get_user(const char __user *pathname, int flags);
>>
>> int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);
>> int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);
>> @@ -331,6 +331,8 @@ int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file,
>> void *key, void *value, u64 map_flags);
>> int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);
>>
>> +int bpf_get_file_flag(int flags);
>> +
>> /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
>> * forced to use 'long' read/writes to try to atomically copy long counters.
>> * Best-effort only. No barriers here, since it _will_ race with concurrent
>> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
>> index 6db9e1d679cd..9cb50a228c39 100644
>> --- a/include/uapi/linux/bpf.h
>> +++ b/include/uapi/linux/bpf.h
>> @@ -217,6 +217,10 @@ enum bpf_attach_type {
>>
>> #define BPF_OBJ_NAME_LEN 16U
>>
>> +/* Flags for accessing BPF object */
>> +#define BPF_F_RDONLY (1U << 3)
>> +#define BPF_F_WRONLY (1U << 4)
>> +
>> union bpf_attr {
>> struct { /* anonymous struct used by BPF_MAP_CREATE command */
>> __u32 map_type; /* one of enum bpf_map_type */
>> @@ -259,6 +263,7 @@ union bpf_attr {
>> struct { /* anonymous struct used by BPF_OBJ_* commands */
>> __aligned_u64 pathname;
>> __u32 bpf_fd;
>> + __u32 file_flags;
>> };
>>
>> struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
>> @@ -286,6 +291,7 @@ union bpf_attr {
>> __u32 map_id;
>> };
>> __u32 next_id;
>> + __u32 open_flags;
>> };
>>
>> struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
>> diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
>> index 68d866628be0..f869e48ef2f6 100644
>> --- a/kernel/bpf/arraymap.c
>> +++ b/kernel/bpf/arraymap.c
>> @@ -19,6 +19,9 @@
>>
>> #include "map_in_map.h"
>>
>> +#define ARRAY_CREATE_FLAG_MASK \
>> + (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY)
>> +
>> static void bpf_array_free_percpu(struct bpf_array *array)
>> {
>> int i;
>> @@ -56,8 +59,8 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr)
>>
>> /* check sanity of attributes */
>> if (attr->max_entries == 0 || attr->key_size != 4 ||
>> - attr->value_size == 0 || attr->map_flags & ~BPF_F_NUMA_NODE ||
>> - (percpu && numa_node != NUMA_NO_NODE))
>> + attr->value_size == 0 || attr->map_flags &
>> + ~ARRAY_CREATE_FLAG_MASK || (percpu && numa_node != NUMA_NO_NODE))
>
> that's very non-standard way of breaking lines.
> Did you run checkpatch ? did it complain?
>
Will fix in next revision, checkpatch didn't say anything about
this....0 error and 0 warning for this patch series.
