+/* -*-c-*-
+ *
+ * $Id: fdpass.c,v 1.1 2003/11/29 11:58:49 mdw Exp $
+ *
+ * File descriptor passing
+ *
+ * (c) 2003 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of the mLib utilities library.
+ *
+ * mLib is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * mLib 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 Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with mLib; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: fdpass.c,v $
+ * Revision 1.1 2003/11/29 11:58:49 mdw
+ * File descriptor passing.
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <sys/types.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <sys/un.h>
+
+#include "fdpass.h"
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @fdpass_send@ --- *
+ *
+ * Arguments: @int sock@ = socket to send over
+ * @int fd@ = file descriptor to send
+ * @const void *p@ = pointer to data to send
+ * @size_t sz@ = size of buffer to send
+ *
+ * Returns: On error, @-1@, otherwise number of bytes transferred from
+ * @p@.
+ *
+ * Use: Sends a copy of file descriptor @fd@ to the other end of
+ * @sock@.
+ */
+
+ssize_t fdpass_send(int sock, int fd, const void *p, size_t sz)
+{
+ struct iovec iov;
+ struct msghdr msg;
+#ifndef HAVE_MSG_ACCRIGHTS
+ char buf[CMSG_SPACE(sizeof(fd))];
+ struct cmsghdr *cmsg;
+#endif
+
+ iov.iov_base = (/*unconst*/ void *)p;
+ iov.iov_len = sz;
+ msg.msg_name = 0;
+ msg.msg_namelen = 0;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ msg.msg_flags = 0;
+#ifdef HAVE_MSG_ACCRIGHTS
+ msg.msg_accrights = &fd;
+ msg.msg_accrightslen = sizeof(fd);
+#else
+ msg.msg_control = buf;
+ msg.msg_controllen = sizeof(buf);
+ cmsg = CMSG_FIRSTHDR(&msg);
+ cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
+#endif
+ return (sendmsg(sock, &msg, 0));
+}
+
+/* --- @fdpass_recv@ --- *
+ *
+ * Arguments: @int sock@ = socket to send over
+ * @int *fd@ = where to put received descriptor
+ * @void *p@ = pointer to where to put data
+ * @size_t sz@ = size of buffer
+ *
+ * Returns: On error, @-1@, otherwise number of bytes transferred.
+ *
+ * Use: Receives a file descriptor. If the call succeeds, and there
+ * was a file descriptor, then @fd@ won't be @-1@ on exit;
+ * otherwise it will. At most one descriptor will be collected.
+ */
+
+ssize_t fdpass_recv(int sock, int *fd, void *p, size_t sz)
+{
+ struct iovec iov;
+ struct msghdr msg;
+ ssize_t rc;
+#ifndef HAVE_MSG_ACCRIGHTS
+ char buf[CMSG_SPACE(sizeof(fd))];
+ struct cmsghdr *cmsg;
+ int fdtmp;
+#endif
+
+ *fd = -1;
+ iov.iov_base = p;
+ iov.iov_len = sz;
+ msg.msg_name = 0;
+ msg.msg_namelen = 0;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ msg.msg_flags = 0;
+#ifdef HAVE_MSG_ACCRIGHTS
+ msg.msg_accrights = fd;
+ msg.msg_accrightslen = sizeof(*fd);
+#else
+ msg.msg_control = buf;
+ msg.msg_controllen = sizeof(buf);
+#endif
+ if ((rc = recvmsg(sock, &msg, 0)) < 0)
+ return (rc);
+#ifdef HAVE_MSG_ACCRIGHTS
+ if (msg.msg_accrightslen < sizeof(*fd))
+ *fd = -1;
+#else
+ for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+ if (cmsg->cmsg_level == SOL_SOCKET &&
+ cmsg->cmsg_type == SCM_RIGHTS &&
+ cmsg->cmsg_len >= CMSG_LEN(sizeof(fd))) {
+ memcpy(&fdtmp, CMSG_DATA(cmsg), sizeof(fdtmp));
+ if (*fd == -1)
+ *fd = fdtmp;
+ else
+ close(fdtmp);
+ }
+ }
+#endif
+ return (rc);
+}
+
+/*----- That's all, folks -------------------------------------------------*/
~mdw / mLib / commitdiff