diff options
Diffstat (limited to 'lib/imsg.c')
| -rw-r--r-- | lib/imsg.c | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/lib/imsg.c b/lib/imsg.c new file mode 100644 index 0000000..057e4b3 --- /dev/null +++ b/lib/imsg.c @@ -0,0 +1,316 @@ +// SPDX-License-Identifier: ISC +/* $OpenBSD$ */ + +/* + * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org> + */ + +#include <zebra.h> + +#include "memory.h" +#include "queue.h" +#include "imsg.h" + +static int imsg_fd_overhead = 0; + +static int imsg_get_fd(struct imsgbuf *); + +#ifndef __OpenBSD__ +/* + * The original code calls getdtablecount() which is OpenBSD specific. Use + * available_fds() from OpenSMTPD instead. + */ +static int available_fds(unsigned int n) +{ + unsigned int i; + int ret, fds[256]; + + if (n > (unsigned int)array_size(fds)) + return 1; + + ret = 0; + for (i = 0; i < n; i++) { + fds[i] = -1; + if ((fds[i] = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { + if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT) + fds[i] = socket(AF_INET6, SOCK_DGRAM, 0); + if (fds[i] < 0) { + ret = 1; + break; + } + } + } + + for (i = 0; i < n && fds[i] >= 0; i++) + close(fds[i]); + + return (ret); +} +#endif + +void imsg_init(struct imsgbuf *ibuf, int fd) +{ + msgbuf_init(&ibuf->w); + memset(&ibuf->r, 0, sizeof(ibuf->r)); + ibuf->fd = fd; + ibuf->w.fd = fd; + ibuf->pid = getpid(); + TAILQ_INIT(&ibuf->fds); +} + +ssize_t imsg_read(struct imsgbuf *ibuf) +{ + struct msghdr msg; + struct cmsghdr *cmsg; + union { + struct cmsghdr hdr; + char buf[CMSG_SPACE(sizeof(int) * 1)]; + } cmsgbuf; + struct iovec iov; + ssize_t n; + int fd; + struct imsg_fd *ifd; + + memset(&msg, 0, sizeof(msg)); + memset(&cmsgbuf, 0, sizeof(cmsgbuf)); + + iov.iov_base = ibuf->r.buf + ibuf->r.wpos; + iov.iov_len = sizeof(ibuf->r.buf) - ibuf->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: +#ifdef __OpenBSD__ + if (getdtablecount() + imsg_fd_overhead + + (int)((CMSG_SPACE(sizeof(int)) - CMSG_SPACE(0)) + / sizeof(int)) + >= getdtablesize()) { +#else + if (available_fds(imsg_fd_overhead + + (CMSG_SPACE(sizeof(int)) - CMSG_SPACE(0)) + / sizeof(int))) { +#endif + errno = EAGAIN; + free(ifd); + return -1; + } + + n = recvmsg(ibuf->fd, &msg, 0); + if (n == -1) { + if (errno == EINTR) + goto again; + goto fail; + } + + ibuf->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(&ibuf->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 *ibuf, struct imsg *imsg) +{ + size_t av, left, datalen; + + av = ibuf->r.wpos; + + if (IMSG_HEADER_SIZE > av) + return 0; + + memcpy(&imsg->hdr, ibuf->r.buf, sizeof(imsg->hdr)); + if (imsg->hdr.len < IMSG_HEADER_SIZE || imsg->hdr.len > MAX_IMSGSIZE) { + errno = ERANGE; + return -1; + } + if (imsg->hdr.len > av) + return 0; + datalen = imsg->hdr.len - IMSG_HEADER_SIZE; + ibuf->r.rptr = ibuf->r.buf + IMSG_HEADER_SIZE; + if (datalen == 0) + imsg->data = NULL; + else if ((imsg->data = malloc(datalen)) == NULL) + return -1; + + if (imsg->hdr.flags & IMSGF_HASFD) + imsg->fd = imsg_get_fd(ibuf); + else + imsg->fd = -1; + + if (imsg->data) + memcpy(imsg->data, ibuf->r.rptr, datalen); + + if (imsg->hdr.len < av) { + left = av - imsg->hdr.len; + memmove(&ibuf->r.buf, ibuf->r.buf + imsg->hdr.len, left); + ibuf->r.wpos = left; + } else + ibuf->r.wpos = 0; + + return (datalen + IMSG_HEADER_SIZE); +} + +int imsg_compose(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid, + pid_t pid, int fd, const void *data, uint16_t datalen) +{ + struct ibuf *wbuf; + + if ((wbuf = imsg_create(ibuf, type, peerid, pid, datalen)) == NULL) + return -1; + + if (imsg_add(wbuf, data, datalen) == -1) + return -1; + + wbuf->fd = fd; + + imsg_close(ibuf, wbuf); + + return 1; +} + +int imsg_composev(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid, + pid_t pid, int fd, const struct iovec *iov, int iovcnt) +{ + struct ibuf *wbuf; + int i, datalen = 0; + + for (i = 0; i < iovcnt; i++) + datalen += iov[i].iov_len; + + if ((wbuf = imsg_create(ibuf, type, peerid, 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; + + wbuf->fd = fd; + + imsg_close(ibuf, wbuf); + + return 1; +} + +/* ARGSUSED */ +struct ibuf *imsg_create(struct imsgbuf *ibuf, uint32_t type, uint32_t peerid, + pid_t pid, uint16_t datalen) +{ + struct ibuf *wbuf; + struct imsg_hdr hdr; + + memset(&hdr, 0x00, IMSG_HEADER_SIZE); + + datalen += IMSG_HEADER_SIZE; + if (datalen > MAX_IMSGSIZE) { + errno = ERANGE; + return NULL; + } + + hdr.type = type; + hdr.flags = 0; + hdr.peerid = peerid; + if ((hdr.pid = pid) == 0) + hdr.pid = ibuf->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, uint16_t datalen) +{ + if (datalen) + if (ibuf_add(msg, data, datalen) == -1) { + ibuf_free(msg); + return -1; + } + return (datalen); +} + +void imsg_close(struct imsgbuf *ibuf, struct ibuf *msg) +{ + struct imsg_hdr *hdr; + + hdr = (struct imsg_hdr *)msg->buf; + + hdr->flags &= ~IMSGF_HASFD; + if (msg->fd != -1) + hdr->flags |= IMSGF_HASFD; + + hdr->len = (uint16_t)msg->wpos; + + ibuf_close(&ibuf->w, msg); +} + +void imsg_free(struct imsg *imsg) +{ + free(imsg->data); +} + +int imsg_get_fd(struct imsgbuf *ibuf) +{ + int fd; + struct imsg_fd *ifd; + + if ((ifd = TAILQ_POP_FIRST(&ibuf->fds, entry)) == NULL) + return -1; + + fd = ifd->fd; + free(ifd); + + return (fd); +} + +int imsg_flush(struct imsgbuf *ibuf) +{ + while (ibuf->w.queued) + if (msgbuf_write(&ibuf->w) <= 0) + return -1; + return 0; +} + +void imsg_clear(struct imsgbuf *ibuf) +{ + int fd; + + msgbuf_clear(&ibuf->w); + while ((fd = imsg_get_fd(ibuf)) != -1) + close(fd); +} |