Mirror of the official OpenWrt ubus repository https://git.openwrt.org/project/ubus
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/*
* Copyright (C) 2011-2014 Felix Fietkau <nbd@openwrt.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1
* as published by the Free Software Foundation
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/socket.h>
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
#include <libubox/usock.h>
#include <libubox/blob.h>
#include <libubox/blobmsg.h>
#include "libubus.h"
#include "libubus-internal.h"
#define STATIC_IOV(_var) { .iov_base = (char *) &(_var), .iov_len = sizeof(_var) }
#define UBUS_MSGBUF_REDUCTION_INTERVAL 16
static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
[UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },
[UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },
[UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },
[UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },
[UBUS_ATTR_ACTIVE] = { .type = BLOB_ATTR_INT8 },
[UBUS_ATTR_NO_REPLY] = { .type = BLOB_ATTR_INT8 },
[UBUS_ATTR_SUBSCRIBERS] = { .type = BLOB_ATTR_NESTED },
};
static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
__hidden struct blob_attr **ubus_parse_msg(struct blob_attr *msg, size_t len)
{
blob_parse_untrusted(msg, len, attrbuf, ubus_policy, UBUS_ATTR_MAX);
return attrbuf;
}
static void wait_data(int fd, bool write)
{
struct pollfd pfd = { .fd = fd };
pfd.events = write ? POLLOUT : POLLIN;
poll(&pfd, 1, -1);
}
static int writev_retry(int fd, struct iovec *iov, int iov_len, int sock_fd)
{
uint8_t fd_buf[CMSG_SPACE(sizeof(int))] = { 0 };
struct msghdr msghdr = { 0 };
struct cmsghdr *cmsg;
int len = 0;
int *pfd;
msghdr.msg_iov = iov,
msghdr.msg_iovlen = iov_len,
msghdr.msg_control = fd_buf;
msghdr.msg_controllen = sizeof(fd_buf);
cmsg = CMSG_FIRSTHDR(&msghdr);
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
pfd = (int *) CMSG_DATA(cmsg);
msghdr.msg_controllen = cmsg->cmsg_len;
do {
ssize_t cur_len;
if (sock_fd < 0) {
msghdr.msg_control = NULL;
msghdr.msg_controllen = 0;
} else {
*pfd = sock_fd;
}
cur_len = sendmsg(fd, &msghdr, 0);
if (cur_len < 0) {
switch(errno) {
case EAGAIN:
wait_data(fd, true);
break;
case EINTR:
break;
default:
return -1;
}
continue;
}
if (len > 0)
sock_fd = -1;
len += cur_len;
while (cur_len >= (ssize_t) iov->iov_len) {
cur_len -= iov->iov_len;
iov_len--;
iov++;
if (!iov_len)
return len;
}
iov->iov_base += cur_len;
iov->iov_len -= cur_len;
msghdr.msg_iov = iov;
msghdr.msg_iovlen = iov_len;
} while (1);
/* Should never reach here */
return -1;
}
int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
struct blob_attr *msg, int cmd, uint32_t peer, int fd)
{
struct ubus_msghdr hdr;
struct iovec iov[2] = {
STATIC_IOV(hdr)
};
int ret;
hdr.version = 0;
hdr.type = cmd;
hdr.seq = cpu_to_be16(seq);
hdr.peer = cpu_to_be32(peer);
if (!msg) {
blob_buf_init(&b, 0);
msg = b.head;
}
iov[1].iov_base = (char *) msg;
iov[1].iov_len = blob_raw_len(msg);
ret = writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov), fd);
if (ret < 0)
ctx->sock.eof = true;
if (fd >= 0)
close(fd);
return ret;
}
static int recv_retry(struct ubus_context *ctx, struct iovec *iov, bool wait, int *recv_fd)
{
uint8_t fd_buf[CMSG_SPACE(sizeof(int))] = { 0 };
struct msghdr msghdr = { 0 };
struct cmsghdr *cmsg;
int total = 0;
int bytes;
int *pfd;
int fd;
fd = ctx->sock.fd;
msghdr.msg_iov = iov,
msghdr.msg_iovlen = 1,
msghdr.msg_control = fd_buf;
msghdr.msg_controllen = sizeof(fd_buf);
cmsg = CMSG_FIRSTHDR(&msghdr);
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
pfd = (int *) CMSG_DATA(cmsg);
while (iov->iov_len > 0) {
if (recv_fd) {
msghdr.msg_control = fd_buf;
msghdr.msg_controllen = cmsg->cmsg_len;
} else {
msghdr.msg_control = NULL;
msghdr.msg_controllen = 0;
}
*pfd = -1;
bytes = recvmsg(fd, &msghdr, 0);
if (!bytes)
return -1;
if (bytes < 0) {
bytes = 0;
if (errno == EINTR)
continue;
if (errno != EAGAIN)
return -1;
}
if (!wait && !bytes)
return 0;
if (recv_fd)
*recv_fd = *pfd;
recv_fd = NULL;
wait = true;
iov->iov_len -= bytes;
iov->iov_base += bytes;
total += bytes;
if (iov->iov_len > 0)
wait_data(fd, false);
}
return total;
}
bool ubus_validate_hdr(struct ubus_msghdr *hdr)
{
struct blob_attr *data = (struct blob_attr *) (hdr + 1);
if (hdr->version != 0)
return false;
if (blob_raw_len(data) < sizeof(*data))
return false;
if (blob_pad_len(data) > UBUS_MAX_MSGLEN)
return false;
return true;
}
static bool alloc_msg_buf(struct ubus_context *ctx, int len)
{
void *ptr;
int buf_len = ctx->msgbuf_data_len;
int rem;
if (!ctx->msgbuf.data)
buf_len = 0;
rem = (len % UBUS_MSG_CHUNK_SIZE);
if (rem > 0)
len += UBUS_MSG_CHUNK_SIZE - rem;
if (len < buf_len &&
++ctx->msgbuf_reduction_counter > UBUS_MSGBUF_REDUCTION_INTERVAL) {
ctx->msgbuf_reduction_counter = 0;
buf_len = 0;
}
if (len <= buf_len)
return true;
ptr = realloc(ctx->msgbuf.data, len);
if (!ptr)
return false;
ctx->msgbuf.data = ptr;
ctx->msgbuf_data_len = len;
return true;
}
static bool get_next_msg(struct ubus_context *ctx, int *recv_fd)
{
struct {
struct ubus_msghdr hdr;
struct blob_attr data;
} hdrbuf;
struct iovec iov = STATIC_IOV(hdrbuf);
int len;
int r;
/* receive header + start attribute */
r = recv_retry(ctx, &iov, false, recv_fd);
if (r <= 0) {
if (r < 0)
ctx->sock.eof = true;
return false;
}
hdrbuf.hdr.seq = be16_to_cpu(hdrbuf.hdr.seq);
hdrbuf.hdr.peer = be32_to_cpu(hdrbuf.hdr.peer);
if (!ubus_validate_hdr(&hdrbuf.hdr))
return false;
len = blob_raw_len(&hdrbuf.data);
if (!alloc_msg_buf(ctx, len))
return false;
memcpy(&ctx->msgbuf.hdr, &hdrbuf.hdr, sizeof(hdrbuf.hdr));
memcpy(ctx->msgbuf.data, &hdrbuf.data, sizeof(hdrbuf.data));
iov.iov_base = (char *)ctx->msgbuf.data + sizeof(hdrbuf.data);
iov.iov_len = blob_len(ctx->msgbuf.data);
if (iov.iov_len > 0 &&
recv_retry(ctx, &iov, true, NULL) <= 0)
return false;
return true;
}
void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
{
struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
int recv_fd = -1;
while (get_next_msg(ctx, &recv_fd)) {
ubus_process_msg(ctx, &ctx->msgbuf, recv_fd);
if (uloop_cancelling() || ctx->cancel_poll)
break;
}
if (u->eof)
ctx->connection_lost(ctx);
}
void __hidden ubus_poll_data(struct ubus_context *ctx, int timeout)
{
struct pollfd pfd = {
.fd = ctx->sock.fd,
.events = POLLIN | POLLERR,
};
ctx->cancel_poll = false;
poll(&pfd, 1, timeout ? timeout : -1);
ubus_handle_data(&ctx->sock, ULOOP_READ);
}
static void
ubus_refresh_state(struct ubus_context *ctx)
{
struct ubus_object *obj, *tmp;
struct ubus_object **objs;
int n, i = 0;
/* clear all type IDs, they need to be registered again */
avl_for_each_element(&ctx->objects, obj, avl)
if (obj->type)
obj->type->id = 0;
/* push out all objects again */
objs = alloca(ctx->objects.count * sizeof(*objs));
avl_remove_all_elements(&ctx->objects, obj, avl, tmp) {
objs[i++] = obj;
obj->id = 0;
}
for (n = i, i = 0; i < n; i++)
ubus_add_object(ctx, objs[i]);
}
int ubus_reconnect(struct ubus_context *ctx, const char *path)
{
struct {
struct ubus_msghdr hdr;
struct blob_attr data;
} hdr;
struct blob_attr *buf;
int ret = UBUS_STATUS_UNKNOWN_ERROR;
if (!path)
path = UBUS_UNIX_SOCKET;
if (ctx->sock.fd >= 0) {
if (ctx->sock.registered)
uloop_fd_delete(&ctx->sock);
close(ctx->sock.fd);
}
ctx->sock.eof = false;
ctx->sock.error = false;
ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
if (ctx->sock.fd < 0)
return UBUS_STATUS_CONNECTION_FAILED;
if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
goto out_close;
if (!ubus_validate_hdr(&hdr.hdr))
goto out_close;
if (hdr.hdr.type != UBUS_MSG_HELLO)
goto out_close;
buf = calloc(1, blob_raw_len(&hdr.data));
if (!buf)
goto out_close;
memcpy(buf, &hdr.data, sizeof(hdr.data));
if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != (ssize_t) blob_len(buf))
goto out_free;
ctx->local_id = hdr.hdr.peer;
if (!ctx->local_id)
goto out_free;
ret = UBUS_STATUS_OK;
fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK | O_CLOEXEC);
ubus_refresh_state(ctx);
out_free:
free(buf);
out_close:
if (ret)
close(ctx->sock.fd);
return ret;
}