f09d18878b
As the man page explains: "Specifying a timeout of zero causes poll() to return immediately, even if no file descriptors are ready." The use of 0 as timeout could cause libubus to busy loop if the socket was non-blocking. For blocking sockets, this was less apparent as the subsequent read() would then block. Signed-off-by: Karl Vogel <karl.vogel@gmail.com>
407 lines
8.1 KiB
C
407 lines
8.1 KiB
C
/*
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* Copyright (C) 2011-2014 Felix Fietkau <nbd@openwrt.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License version 2.1
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* as published by the Free Software Foundation
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define _GNU_SOURCE
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#include <sys/types.h>
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#include <sys/uio.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <poll.h>
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#include <libubox/usock.h>
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#include <libubox/blob.h>
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#include <libubox/blobmsg.h>
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#include "libubus.h"
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#include "libubus-internal.h"
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#define STATIC_IOV(_var) { .iov_base = (char *) &(_var), .iov_len = sizeof(_var) }
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#define UBUS_MSGBUF_REDUCTION_INTERVAL 16
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static const struct blob_attr_info ubus_policy[UBUS_ATTR_MAX] = {
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[UBUS_ATTR_STATUS] = { .type = BLOB_ATTR_INT32 },
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[UBUS_ATTR_OBJID] = { .type = BLOB_ATTR_INT32 },
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[UBUS_ATTR_OBJPATH] = { .type = BLOB_ATTR_STRING },
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[UBUS_ATTR_METHOD] = { .type = BLOB_ATTR_STRING },
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[UBUS_ATTR_ACTIVE] = { .type = BLOB_ATTR_INT8 },
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[UBUS_ATTR_NO_REPLY] = { .type = BLOB_ATTR_INT8 },
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[UBUS_ATTR_SUBSCRIBERS] = { .type = BLOB_ATTR_NESTED },
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};
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static struct blob_attr *attrbuf[UBUS_ATTR_MAX];
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__hidden struct blob_attr **ubus_parse_msg(struct blob_attr *msg)
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{
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blob_parse(msg, attrbuf, ubus_policy, UBUS_ATTR_MAX);
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return attrbuf;
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}
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static void wait_data(int fd, bool write)
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{
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struct pollfd pfd = { .fd = fd };
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pfd.events = write ? POLLOUT : POLLIN;
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poll(&pfd, 1, -1);
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}
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static int writev_retry(int fd, struct iovec *iov, int iov_len, int sock_fd)
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{
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static struct {
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struct cmsghdr h;
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int fd;
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} fd_buf = {
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.h = {
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.cmsg_len = sizeof(fd_buf),
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.cmsg_level = SOL_SOCKET,
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.cmsg_type = SCM_RIGHTS,
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}
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};
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struct msghdr msghdr = {
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.msg_iov = iov,
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.msg_iovlen = iov_len,
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.msg_control = &fd_buf,
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.msg_controllen = sizeof(fd_buf),
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};
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int len = 0;
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do {
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int cur_len;
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if (sock_fd < 0) {
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msghdr.msg_control = NULL;
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msghdr.msg_controllen = 0;
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} else {
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fd_buf.fd = sock_fd;
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}
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cur_len = sendmsg(fd, &msghdr, 0);
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if (cur_len < 0) {
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switch(errno) {
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case EAGAIN:
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wait_data(fd, true);
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break;
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case EINTR:
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break;
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default:
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return -1;
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}
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continue;
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}
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if (len > 0)
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sock_fd = -1;
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len += cur_len;
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while (cur_len >= iov->iov_len) {
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cur_len -= iov->iov_len;
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iov_len--;
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iov++;
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if (!iov_len)
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return len;
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}
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iov->iov_base += cur_len;
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iov->iov_len -= cur_len;
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msghdr.msg_iov = iov;
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msghdr.msg_iovlen = iov_len;
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} while (1);
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/* Should never reach here */
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return -1;
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}
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int __hidden ubus_send_msg(struct ubus_context *ctx, uint32_t seq,
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struct blob_attr *msg, int cmd, uint32_t peer, int fd)
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{
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struct ubus_msghdr hdr;
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struct iovec iov[2] = {
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STATIC_IOV(hdr)
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};
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int ret;
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hdr.version = 0;
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hdr.type = cmd;
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hdr.seq = seq;
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hdr.peer = peer;
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if (!msg) {
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blob_buf_init(&b, 0);
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msg = b.head;
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}
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iov[1].iov_base = (char *) msg;
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iov[1].iov_len = blob_raw_len(msg);
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ret = writev_retry(ctx->sock.fd, iov, ARRAY_SIZE(iov), fd);
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if (ret < 0)
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ctx->sock.eof = true;
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if (fd >= 0)
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close(fd);
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return ret;
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}
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static int recv_retry(int fd, struct iovec *iov, bool wait, int *recv_fd)
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{
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int bytes, total = 0;
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static struct {
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struct cmsghdr h;
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int fd;
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} fd_buf = {
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.h = {
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.cmsg_type = SCM_RIGHTS,
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.cmsg_level = SOL_SOCKET,
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.cmsg_len = sizeof(fd_buf),
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},
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};
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struct msghdr msghdr = {
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.msg_iov = iov,
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.msg_iovlen = 1,
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};
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while (iov->iov_len > 0) {
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if (wait)
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wait_data(fd, false);
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if (recv_fd) {
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msghdr.msg_control = &fd_buf;
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msghdr.msg_controllen = sizeof(fd_buf);
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} else {
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msghdr.msg_control = NULL;
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msghdr.msg_controllen = 0;
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}
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fd_buf.fd = -1;
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bytes = recvmsg(fd, &msghdr, 0);
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if (!bytes)
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return -1;
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if (bytes < 0) {
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bytes = 0;
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if (uloop_cancelled)
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return 0;
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if (errno == EINTR)
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continue;
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if (errno != EAGAIN)
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return -1;
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}
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if (!wait && !bytes)
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return 0;
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if (recv_fd)
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*recv_fd = fd_buf.fd;
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recv_fd = NULL;
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wait = true;
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iov->iov_len -= bytes;
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iov->iov_base += bytes;
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total += bytes;
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}
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return total;
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}
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static bool ubus_validate_hdr(struct ubus_msghdr *hdr)
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{
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struct blob_attr *data = (struct blob_attr *) (hdr + 1);
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if (hdr->version != 0)
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return false;
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if (blob_raw_len(data) < sizeof(*data))
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return false;
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if (blob_pad_len(data) > UBUS_MAX_MSGLEN)
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return false;
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return true;
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}
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static bool alloc_msg_buf(struct ubus_context *ctx, int len)
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{
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void *ptr;
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int buf_len = ctx->msgbuf_data_len;
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int rem;
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if (!ctx->msgbuf.data)
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buf_len = 0;
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rem = (len % UBUS_MSG_CHUNK_SIZE);
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if (rem > 0)
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len += UBUS_MSG_CHUNK_SIZE - rem;
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if (len < buf_len &&
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++ctx->msgbuf_reduction_counter > UBUS_MSGBUF_REDUCTION_INTERVAL) {
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ctx->msgbuf_reduction_counter = 0;
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buf_len = 0;
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}
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if (len <= buf_len)
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return true;
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ptr = realloc(ctx->msgbuf.data, len);
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if (!ptr)
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return false;
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ctx->msgbuf.data = ptr;
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return true;
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}
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static bool get_next_msg(struct ubus_context *ctx, int *recv_fd)
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{
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struct {
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struct ubus_msghdr hdr;
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struct blob_attr data;
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} hdrbuf;
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struct iovec iov = STATIC_IOV(hdrbuf);
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int len;
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int r;
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/* receive header + start attribute */
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r = recv_retry(ctx->sock.fd, &iov, false, recv_fd);
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if (r <= 0) {
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if (r < 0)
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ctx->sock.eof = true;
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return false;
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}
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if (!ubus_validate_hdr(&hdrbuf.hdr))
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return false;
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len = blob_raw_len(&hdrbuf.data);
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if (!alloc_msg_buf(ctx, len))
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return false;
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memcpy(&ctx->msgbuf.hdr, &hdrbuf.hdr, sizeof(hdrbuf.hdr));
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memcpy(ctx->msgbuf.data, &hdrbuf.data, sizeof(hdrbuf.data));
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iov.iov_base = (char *)ctx->msgbuf.data + sizeof(hdrbuf.data);
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iov.iov_len = blob_len(ctx->msgbuf.data);
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if (iov.iov_len > 0 && !recv_retry(ctx->sock.fd, &iov, true, NULL))
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return false;
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return true;
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}
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void __hidden ubus_handle_data(struct uloop_fd *u, unsigned int events)
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{
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struct ubus_context *ctx = container_of(u, struct ubus_context, sock);
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int recv_fd = -1;
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while (get_next_msg(ctx, &recv_fd)) {
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ubus_process_msg(ctx, &ctx->msgbuf, recv_fd);
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if (uloop_cancelled)
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break;
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}
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if (u->eof)
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ctx->connection_lost(ctx);
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}
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void __hidden ubus_poll_data(struct ubus_context *ctx, int timeout)
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{
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struct pollfd pfd = {
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.fd = ctx->sock.fd,
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.events = POLLIN | POLLERR,
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};
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poll(&pfd, 1, timeout ? timeout : -1);
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ubus_handle_data(&ctx->sock, ULOOP_READ);
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}
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static void
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ubus_refresh_state(struct ubus_context *ctx)
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{
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struct ubus_object *obj, *tmp;
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struct ubus_object **objs;
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int n, i = 0;
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/* clear all type IDs, they need to be registered again */
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avl_for_each_element(&ctx->objects, obj, avl)
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if (obj->type)
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obj->type->id = 0;
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/* push out all objects again */
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objs = alloca(ctx->objects.count * sizeof(*objs));
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avl_remove_all_elements(&ctx->objects, obj, avl, tmp) {
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objs[i++] = obj;
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obj->id = 0;
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}
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for (n = i, i = 0; i < n; i++)
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ubus_add_object(ctx, objs[i]);
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}
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int ubus_reconnect(struct ubus_context *ctx, const char *path)
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{
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struct {
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struct ubus_msghdr hdr;
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struct blob_attr data;
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} hdr;
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struct blob_attr *buf;
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int ret = UBUS_STATUS_UNKNOWN_ERROR;
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if (!path)
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path = UBUS_UNIX_SOCKET;
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if (ctx->sock.fd >= 0) {
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if (ctx->sock.registered)
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uloop_fd_delete(&ctx->sock);
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close(ctx->sock.fd);
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}
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ctx->sock.fd = usock(USOCK_UNIX, path, NULL);
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if (ctx->sock.fd < 0)
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return UBUS_STATUS_CONNECTION_FAILED;
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if (read(ctx->sock.fd, &hdr, sizeof(hdr)) != sizeof(hdr))
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goto out_close;
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if (!ubus_validate_hdr(&hdr.hdr))
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goto out_close;
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if (hdr.hdr.type != UBUS_MSG_HELLO)
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goto out_close;
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buf = calloc(1, blob_raw_len(&hdr.data));
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if (!buf)
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goto out_close;
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memcpy(buf, &hdr.data, sizeof(hdr.data));
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if (read(ctx->sock.fd, blob_data(buf), blob_len(buf)) != blob_len(buf))
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goto out_free;
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ctx->local_id = hdr.hdr.peer;
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if (!ctx->local_id)
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goto out_free;
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ret = UBUS_STATUS_OK;
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fcntl(ctx->sock.fd, F_SETFL, fcntl(ctx->sock.fd, F_GETFL) | O_NONBLOCK | O_CLOEXEC);
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ubus_refresh_state(ctx);
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out_free:
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free(buf);
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out_close:
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if (ret)
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close(ctx->sock.fd);
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return ret;
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}
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