tools: ynl: wrap recv() + mnl_cb_run2() into a single helper

All callers to mnl_cb_run2() call mnl_socket_recvfrom() right before.
Wrap the two in a helper, take typed arguments (struct ynl_parse_arg),
instead of hoping that all callers remember that parser error handling
requires yarg.

In case of ynl_sock_read_family() we will no longer check for kernel
returning no data, but that would be a kernel bug, not worth complicating
the code to catch this. Calling mnl_cb_run2() on an empty buffer
is legal and results in STOP (1).

Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20240227223032.1835527-9-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2024-02-27 14:30:25 -08:00
parent 9c29a11316
commit 2f22f0b313

View file

@ -491,6 +491,19 @@ int ynl_cb_null(const struct nlmsghdr *nlh, void *data)
return MNL_CB_ERROR;
}
static int ynl_sock_read_msgs(struct ynl_parse_arg *yarg, mnl_cb_t cb)
{
struct ynl_sock *ys = yarg->ys;
ssize_t len;
len = mnl_socket_recvfrom(ys->sock, ys->rx_buf, MNL_SOCKET_BUFFER_SIZE);
if (len < 0)
return len;
return mnl_cb_run2(ys->rx_buf, len, ys->seq, ys->portid,
cb, yarg, ynl_cb_array, NLMSG_MIN_TYPE);
}
/* Init/fini and genetlink boiler plate */
static int
ynl_get_family_info_mcast(struct ynl_sock *ys, const struct nlattr *mcasts)
@ -572,14 +585,7 @@ static int ynl_sock_read_family(struct ynl_sock *ys, const char *family_name)
return err;
}
err = mnl_socket_recvfrom(ys->sock, ys->rx_buf, MNL_SOCKET_BUFFER_SIZE);
if (err <= 0) {
perr(ys, "failed to receive the socket family info");
return err;
}
err = mnl_cb_run2(ys->rx_buf, err, ys->seq, ys->portid,
ynl_get_family_info_cb, &yarg,
ynl_cb_array, ARRAY_SIZE(ynl_cb_array));
err = ynl_sock_read_msgs(&yarg, ynl_get_family_info_cb);
if (err < 0) {
free(ys->mcast_groups);
perr(ys, "failed to receive the socket family info - no such family?");
@ -755,7 +761,6 @@ static int ynl_ntf_trampoline(const struct nlmsghdr *nlh, void *data)
int ynl_ntf_check(struct ynl_sock *ys)
{
struct ynl_parse_arg yarg = { .ys = ys, };
ssize_t len;
int err;
do {
@ -770,14 +775,7 @@ int ynl_ntf_check(struct ynl_sock *ys)
if (err < 1)
return err;
len = mnl_socket_recvfrom(ys->sock, ys->rx_buf,
MNL_SOCKET_BUFFER_SIZE);
if (len < 0)
return len;
err = mnl_cb_run2(ys->rx_buf, len, ys->seq, ys->portid,
ynl_ntf_trampoline, &yarg,
ynl_cb_array, NLMSG_MIN_TYPE);
err = ynl_sock_read_msgs(&yarg, ynl_ntf_trampoline);
if (err < 0)
return err;
} while (err > 0);
@ -834,7 +832,6 @@ static int ynl_req_trampoline(const struct nlmsghdr *nlh, void *data)
int ynl_exec(struct ynl_sock *ys, struct nlmsghdr *req_nlh,
struct ynl_req_state *yrs)
{
ssize_t len;
int err;
err = mnl_socket_sendto(ys->sock, req_nlh, req_nlh->nlmsg_len);
@ -842,19 +839,10 @@ int ynl_exec(struct ynl_sock *ys, struct nlmsghdr *req_nlh,
return err;
do {
len = mnl_socket_recvfrom(ys->sock, ys->rx_buf,
MNL_SOCKET_BUFFER_SIZE);
if (len < 0)
return len;
err = mnl_cb_run2(ys->rx_buf, len, ys->seq, ys->portid,
ynl_req_trampoline, yrs,
ynl_cb_array, NLMSG_MIN_TYPE);
if (err < 0)
return err;
err = ynl_sock_read_msgs(&yrs->yarg, ynl_req_trampoline);
} while (err > 0);
return 0;
return err;
}
static int ynl_dump_trampoline(const struct nlmsghdr *nlh, void *data)
@ -896,7 +884,6 @@ static void *ynl_dump_end(struct ynl_dump_state *ds)
int ynl_exec_dump(struct ynl_sock *ys, struct nlmsghdr *req_nlh,
struct ynl_dump_state *yds)
{
ssize_t len;
int err;
err = mnl_socket_sendto(ys->sock, req_nlh, req_nlh->nlmsg_len);
@ -904,14 +891,7 @@ int ynl_exec_dump(struct ynl_sock *ys, struct nlmsghdr *req_nlh,
return err;
do {
len = mnl_socket_recvfrom(ys->sock, ys->rx_buf,
MNL_SOCKET_BUFFER_SIZE);
if (len < 0)
goto err_close_list;
err = mnl_cb_run2(ys->rx_buf, len, ys->seq, ys->portid,
ynl_dump_trampoline, yds,
ynl_cb_array, NLMSG_MIN_TYPE);
err = ynl_sock_read_msgs(&yds->yarg, ynl_dump_trampoline);
if (err < 0)
goto err_close_list;
} while (err > 0);