mirror of https://github.com/omar-polo/gmid.git
450 lines
8.7 KiB
C
450 lines
8.7 KiB
C
/* $OpenBSD: imsg.c,v 1.23 2023/12/12 15:47:41 claudio Exp $ */
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/*
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* Copyright (c) 2023 Claudio Jeker <claudio@openbsd.org>
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* Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "../config.h"
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/uio.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "imsg.h"
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struct imsg_fd {
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TAILQ_ENTRY(imsg_fd) entry;
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int fd;
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};
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int imsg_fd_overhead = 0;
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static int imsg_dequeue_fd(struct imsgbuf *);
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void
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imsg_init(struct imsgbuf *imsgbuf, int fd)
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{
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msgbuf_init(&imsgbuf->w);
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memset(&imsgbuf->r, 0, sizeof(imsgbuf->r));
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imsgbuf->fd = fd;
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imsgbuf->w.fd = fd;
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imsgbuf->pid = getpid();
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TAILQ_INIT(&imsgbuf->fds);
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}
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ssize_t
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imsg_read(struct imsgbuf *imsgbuf)
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{
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struct msghdr msg;
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struct cmsghdr *cmsg;
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union {
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struct cmsghdr hdr;
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char buf[CMSG_SPACE(sizeof(int) * 1)];
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} cmsgbuf;
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struct iovec iov;
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ssize_t n = -1;
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int fd;
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struct imsg_fd *ifd;
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memset(&msg, 0, sizeof(msg));
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memset(&cmsgbuf, 0, sizeof(cmsgbuf));
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iov.iov_base = imsgbuf->r.buf + imsgbuf->r.wpos;
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iov.iov_len = sizeof(imsgbuf->r.buf) - imsgbuf->r.wpos;
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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msg.msg_control = &cmsgbuf.buf;
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msg.msg_controllen = sizeof(cmsgbuf.buf);
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if ((ifd = calloc(1, sizeof(struct imsg_fd))) == NULL)
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return (-1);
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again:
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if (getdtablecount() + imsg_fd_overhead +
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(int)((CMSG_SPACE(sizeof(int))-CMSG_SPACE(0))/sizeof(int))
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>= getdtablesize()) {
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errno = EAGAIN;
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free(ifd);
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return (-1);
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}
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if ((n = recvmsg(imsgbuf->fd, &msg, 0)) == -1) {
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if (errno == EINTR)
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goto again;
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goto fail;
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}
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imsgbuf->r.wpos += n;
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for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
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cmsg = CMSG_NXTHDR(&msg, cmsg)) {
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if (cmsg->cmsg_level == SOL_SOCKET &&
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cmsg->cmsg_type == SCM_RIGHTS) {
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int i;
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int j;
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/*
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* We only accept one file descriptor. Due to C
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* padding rules, our control buffer might contain
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* more than one fd, and we must close them.
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*/
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j = ((char *)cmsg + cmsg->cmsg_len -
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(char *)CMSG_DATA(cmsg)) / sizeof(int);
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for (i = 0; i < j; i++) {
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fd = ((int *)CMSG_DATA(cmsg))[i];
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if (ifd != NULL) {
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ifd->fd = fd;
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TAILQ_INSERT_TAIL(&imsgbuf->fds, ifd,
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entry);
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ifd = NULL;
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} else
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close(fd);
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}
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}
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/* we do not handle other ctl data level */
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}
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fail:
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free(ifd);
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return (n);
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}
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ssize_t
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imsg_get(struct imsgbuf *imsgbuf, struct imsg *imsg)
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{
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struct imsg m;
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size_t av, left, datalen;
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av = imsgbuf->r.wpos;
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if (IMSG_HEADER_SIZE > av)
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return (0);
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memcpy(&m.hdr, imsgbuf->r.buf, sizeof(m.hdr));
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if (m.hdr.len < IMSG_HEADER_SIZE ||
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m.hdr.len > MAX_IMSGSIZE) {
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errno = ERANGE;
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return (-1);
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}
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if (m.hdr.len > av)
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return (0);
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m.fd = -1;
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m.buf = NULL;
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m.data = NULL;
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datalen = m.hdr.len - IMSG_HEADER_SIZE;
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imsgbuf->r.rptr = imsgbuf->r.buf + IMSG_HEADER_SIZE;
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if (datalen != 0) {
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if ((m.buf = ibuf_open(datalen)) == NULL)
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return (-1);
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if (ibuf_add(m.buf, imsgbuf->r.rptr, datalen) == -1) {
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/* this should never fail */
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ibuf_free(m.buf);
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return (-1);
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}
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m.data = ibuf_data(m.buf);
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}
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if (m.hdr.flags & IMSGF_HASFD)
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m.fd = imsg_dequeue_fd(imsgbuf);
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if (m.hdr.len < av) {
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left = av - m.hdr.len;
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memmove(&imsgbuf->r.buf, imsgbuf->r.buf + m.hdr.len, left);
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imsgbuf->r.wpos = left;
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} else
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imsgbuf->r.wpos = 0;
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*imsg = m;
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return (datalen + IMSG_HEADER_SIZE);
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}
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int
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imsg_get_ibuf(struct imsg *imsg, struct ibuf *ibuf)
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{
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if (imsg->buf == NULL) {
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errno = EBADMSG;
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return (-1);
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}
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return ibuf_get_ibuf(imsg->buf, ibuf_size(imsg->buf), ibuf);
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}
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int
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imsg_get_data(struct imsg *imsg, void *data, size_t len)
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{
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if (len == 0) {
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errno = EINVAL;
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return (-1);
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}
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if (imsg->buf == NULL || ibuf_size(imsg->buf) != len) {
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errno = EBADMSG;
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return (-1);
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}
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return ibuf_get(imsg->buf, data, len);
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}
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int
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imsg_get_fd(struct imsg *imsg)
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{
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int fd = imsg->fd;
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imsg->fd = -1;
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return fd;
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}
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uint32_t
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imsg_get_id(struct imsg *imsg)
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{
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return (imsg->hdr.peerid);
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}
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size_t
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imsg_get_len(struct imsg *imsg)
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{
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if (imsg->buf == NULL)
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return 0;
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return ibuf_size(imsg->buf);
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}
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pid_t
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imsg_get_pid(struct imsg *imsg)
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{
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return (imsg->hdr.pid);
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}
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uint32_t
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imsg_get_type(struct imsg *imsg)
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{
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return (imsg->hdr.type);
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}
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int
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imsg_compose(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
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int fd, const void *data, size_t datalen)
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{
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struct ibuf *wbuf;
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if ((wbuf = imsg_create(imsgbuf, type, id, pid, datalen)) == NULL)
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return (-1);
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if (imsg_add(wbuf, data, datalen) == -1)
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return (-1);
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ibuf_fd_set(wbuf, fd);
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imsg_close(imsgbuf, wbuf);
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return (1);
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}
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int
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imsg_composev(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
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int fd, const struct iovec *iov, int iovcnt)
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{
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struct ibuf *wbuf;
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int i;
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size_t datalen = 0;
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for (i = 0; i < iovcnt; i++)
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datalen += iov[i].iov_len;
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if ((wbuf = imsg_create(imsgbuf, type, id, pid, datalen)) == NULL)
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return (-1);
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for (i = 0; i < iovcnt; i++)
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if (imsg_add(wbuf, iov[i].iov_base, iov[i].iov_len) == -1)
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return (-1);
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ibuf_fd_set(wbuf, fd);
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imsg_close(imsgbuf, wbuf);
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return (1);
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}
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/*
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* Enqueue imsg with payload from ibuf buf. fd passing is not possible
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* with this function.
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*/
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int
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imsg_compose_ibuf(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id,
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pid_t pid, struct ibuf *buf)
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{
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struct ibuf *hdrbuf = NULL;
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struct imsg_hdr hdr;
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int save_errno;
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if (ibuf_size(buf) + IMSG_HEADER_SIZE > MAX_IMSGSIZE) {
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errno = ERANGE;
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goto fail;
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}
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hdr.type = type;
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hdr.len = ibuf_size(buf) + IMSG_HEADER_SIZE;
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hdr.flags = 0;
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hdr.peerid = id;
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if ((hdr.pid = pid) == 0)
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hdr.pid = imsgbuf->pid;
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if ((hdrbuf = ibuf_open(IMSG_HEADER_SIZE)) == NULL)
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goto fail;
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if (imsg_add(hdrbuf, &hdr, sizeof(hdr)) == -1)
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goto fail;
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ibuf_close(&imsgbuf->w, hdrbuf);
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ibuf_close(&imsgbuf->w, buf);
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return (1);
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fail:
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save_errno = errno;
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ibuf_free(buf);
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ibuf_free(hdrbuf);
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errno = save_errno;
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return (-1);
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}
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/*
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* Forward imsg to another channel. Any attached fd is closed.
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*/
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int
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imsg_forward(struct imsgbuf *imsgbuf, struct imsg *msg)
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{
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struct ibuf *wbuf;
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size_t len = 0;
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if (msg->fd != -1) {
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close(msg->fd);
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msg->fd = -1;
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}
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if (msg->buf != NULL) {
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ibuf_rewind(msg->buf);
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len = ibuf_size(msg->buf);
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}
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if ((wbuf = imsg_create(imsgbuf, msg->hdr.type, msg->hdr.peerid,
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msg->hdr.pid, len)) == NULL)
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return (-1);
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if (msg->buf != NULL) {
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if (ibuf_add_buf(wbuf, msg->buf) == -1) {
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ibuf_free(wbuf);
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return (-1);
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}
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}
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imsg_close(imsgbuf, wbuf);
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return (1);
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}
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struct ibuf *
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imsg_create(struct imsgbuf *imsgbuf, uint32_t type, uint32_t id, pid_t pid,
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size_t datalen)
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{
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struct ibuf *wbuf;
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struct imsg_hdr hdr;
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datalen += IMSG_HEADER_SIZE;
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if (datalen > MAX_IMSGSIZE) {
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errno = ERANGE;
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return (NULL);
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}
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hdr.type = type;
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hdr.flags = 0;
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hdr.peerid = id;
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if ((hdr.pid = pid) == 0)
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hdr.pid = imsgbuf->pid;
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if ((wbuf = ibuf_dynamic(datalen, MAX_IMSGSIZE)) == NULL) {
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return (NULL);
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}
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if (imsg_add(wbuf, &hdr, sizeof(hdr)) == -1)
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return (NULL);
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return (wbuf);
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}
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int
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imsg_add(struct ibuf *msg, const void *data, size_t datalen)
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{
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if (datalen)
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if (ibuf_add(msg, data, datalen) == -1) {
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ibuf_free(msg);
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return (-1);
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}
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return (datalen);
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}
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void
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imsg_close(struct imsgbuf *imsgbuf, struct ibuf *msg)
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{
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struct imsg_hdr *hdr;
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hdr = (struct imsg_hdr *)msg->buf;
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hdr->flags &= ~IMSGF_HASFD;
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if (ibuf_fd_avail(msg))
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hdr->flags |= IMSGF_HASFD;
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hdr->len = ibuf_size(msg);
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ibuf_close(&imsgbuf->w, msg);
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}
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void
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imsg_free(struct imsg *imsg)
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{
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ibuf_free(imsg->buf);
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}
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static int
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imsg_dequeue_fd(struct imsgbuf *imsgbuf)
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{
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int fd;
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struct imsg_fd *ifd;
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if ((ifd = TAILQ_FIRST(&imsgbuf->fds)) == NULL)
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return (-1);
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fd = ifd->fd;
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TAILQ_REMOVE(&imsgbuf->fds, ifd, entry);
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free(ifd);
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return (fd);
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}
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int
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imsg_flush(struct imsgbuf *imsgbuf)
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{
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while (imsgbuf->w.queued)
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if (msgbuf_write(&imsgbuf->w) <= 0)
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return (-1);
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return (0);
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}
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void
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imsg_clear(struct imsgbuf *imsgbuf)
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{
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int fd;
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msgbuf_clear(&imsgbuf->w);
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while ((fd = imsg_dequeue_fd(imsgbuf)) != -1)
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close(fd);
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}
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