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