[PATCH 2/2] Add APIs to send file descriptors through the network
Keith Packard
keithp at keithp.com
Thu Oct 31 21:10:25 CET 2013
Exposes new TRANS(SendFd)/TRANS(RecvFd) APIs.
Signed-off-by: Keith Packard <keithp at keithp.com>
---
Xtrans.c | 12 +++
Xtrans.h | 4 +
Xtransint.h | 24 ++++++
Xtranssock.c | 233 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
4 files changed, 256 insertions(+), 17 deletions(-)
diff --git a/Xtrans.c b/Xtrans.c
index ac8b13d..7c7967f 100644
--- a/Xtrans.c
+++ b/Xtrans.c
@@ -873,6 +873,18 @@ TRANS(Writev) (XtransConnInfo ciptr, struct iovec *buf, int size)
}
int
+TRANS(SendFd) (XtransConnInfo ciptr, int fd, int do_close)
+{
+ return ciptr->transptr->SendFd(ciptr, fd, do_close);
+}
+
+int
+TRANS(RecvFd) (XtransConnInfo ciptr)
+{
+ return ciptr->transptr->RecvFd(ciptr);
+}
+
+int
TRANS(Disconnect) (XtransConnInfo ciptr)
{
diff --git a/Xtrans.h b/Xtrans.h
index 1b0af45..53b8b62 100644
--- a/Xtrans.h
+++ b/Xtrans.h
@@ -350,6 +350,10 @@ int TRANS(Writev)(
int /* size */
);
+int TRANS(SendFd) (XtransConnInfo ciptr, int fd, int do_close);
+
+int TRANS(RecvFd) (XtransConnInfo ciptr);
+
int TRANS(Disconnect)(
XtransConnInfo /* ciptr */
);
diff --git a/Xtransint.h b/Xtransint.h
index 3bce8dc..dd886db 100644
--- a/Xtransint.h
+++ b/Xtransint.h
@@ -72,6 +72,8 @@ from The Open Group.
# define XTRANSDEBUG 1
#endif
+#define XTRANS_SEND_FDS 1
+
#ifdef WIN32
# define _WILLWINSOCK_
#endif
@@ -123,6 +125,16 @@ from The Open Group.
#define X_TCP_PORT 6000
#endif
+#if XTRANS_SEND_FDS
+
+struct _XtransConnFd {
+ struct _XtransConnFd *next;
+ int fd;
+ int do_close;
+};
+
+#endif
+
struct _XtransConnInfo {
struct _Xtransport *transptr;
int index;
@@ -135,6 +147,8 @@ struct _XtransConnInfo {
int addrlen;
char *peeraddr;
int peeraddrlen;
+ struct _XtransConnFd *recv_fds;
+ struct _XtransConnFd *send_fds;
};
#define XTRANS_OPEN_COTS_CLIENT 1
@@ -275,6 +289,16 @@ typedef struct _Xtransport {
int /* size */
);
+ int (*SendFd)(
+ XtransConnInfo, /* connection */
+ int, /* fd */
+ int /* do_close */
+ );
+
+ int (*RecvFd)(
+ XtransConnInfo /* connection */
+ );
+
int (*Disconnect)(
XtransConnInfo /* connection */
);
diff --git a/Xtranssock.c b/Xtranssock.c
index 24269b2..23150b2 100644
--- a/Xtranssock.c
+++ b/Xtranssock.c
@@ -2097,47 +2097,176 @@ TRANS(SocketBytesReadable) (XtransConnInfo ciptr, BytesReadable_t *pend)
#endif /* WIN32 */
}
+#if XTRANS_SEND_FDS
+
+static void
+appendFd(struct _XtransConnFd **prev, int fd, int do_close)
+{
+ struct _XtransConnFd *cf, *new;
+
+ new = malloc (sizeof (struct _XtransConnFd));
+ if (!new) {
+ /* XXX mark connection as broken */
+ close(fd);
+ return;
+ }
+ new->next = 0;
+ new->fd = fd;
+ new->do_close = do_close;
+ /* search to end of list */
+ for (; (cf = *prev); prev = &(cf->next));
+ *prev = new;
+}
static int
-TRANS(SocketRead) (XtransConnInfo ciptr, char *buf, int size)
+removeFd(struct _XtransConnFd **prev)
+{
+ struct _XtransConnFd *cf;
+ int fd;
+
+ if ((cf = *prev)) {
+ *prev = cf->next;
+ fd = cf->fd;
+ free(cf);
+ } else
+ fd = -1;
+ return fd;
+}
+static void
+discardFd(struct _XtransConnFd **prev, struct _XtransConnFd *upto, int do_close)
{
- prmsg (2,"SocketRead(%d,%p,%d)\n", ciptr->fd, buf, size);
+ struct _XtransConnFd *cf, *next;
-#if defined(WIN32)
- {
- int ret = recv ((SOCKET)ciptr->fd, buf, size, 0);
-#ifdef WIN32
- if (ret == SOCKET_ERROR) errno = WSAGetLastError();
-#endif
- return ret;
+ for (cf = *prev; cf != upto; cf = next) {
+ next = cf->next;
+ if (do_close || cf->do_close)
+ close(cf->fd);
+ free(cf);
}
-#else
- return read (ciptr->fd, buf, size);
-#endif /* WIN32 */
+ *prev = upto;
}
+static void
+cleanupFds(XtransConnInfo ciptr)
+{
+ /* Clean up the send list but don't close the fds */
+ discardFd(&ciptr->send_fds, NULL, 0);
+ /* Clean up the recv list and *do* close the fds */
+ discardFd(&ciptr->recv_fds, NULL, 1);
+}
static int
-TRANS(SocketWrite) (XtransConnInfo ciptr, char *buf, int size)
+nFd(struct _XtransConnFd **prev)
+{
+ struct _XtransConnFd *cf;
+ int n = 0;
+
+ for (cf = *prev; cf; cf = cf->next)
+ n++;
+ return n;
+}
+
+static int
+TRANS(SocketRecvFd) (XtransConnInfo ciptr)
+{
+ prmsg (2, "SocketRecvFd(%d)\n", ciptr->fd);
+ return removeFd(&ciptr->recv_fds);
+}
+static int
+TRANS(SocketSendFd) (XtransConnInfo ciptr, int fd, int do_close)
{
- prmsg (2,"SocketWrite(%d,%p,%d)\n", ciptr->fd, buf, size);
+ appendFd(&ciptr->send_fds, fd, do_close);
+ return 0;
+}
+
+static int
+TRANS(SocketRecvFdInvalid)(XtransConnInfo ciptr)
+{
+ errno = EINVAL;
+ return -1;
+}
+
+static int
+TRANS(SocketSendFdInvalid)(XtransConnInfo ciptr, int fd, int do_close)
+{
+ errno = EINVAL;
+ return -1;
+}
+
+#define MAX_FDS 128
+
+struct fd_pass {
+ struct cmsghdr cmsghdr;
+ int fd[MAX_FDS];
+};
+
+static inline void init_msg_recv(struct msghdr *msg, struct iovec *iov, int niov, struct fd_pass *pass, int nfd) {
+ msg->msg_name = NULL;
+ msg->msg_namelen = 0;
+ msg->msg_iov = iov;
+ msg->msg_iovlen = niov;
+ msg->msg_control = pass;
+ msg->msg_controllen = sizeof (struct cmsghdr) + nfd * sizeof (int);
+}
+
+static inline void init_msg_send(struct msghdr *msg, struct iovec *iov, int niov, struct fd_pass *pass, int nfd) {
+ init_msg_recv(msg, iov, niov, pass, nfd);
+ pass->cmsghdr.cmsg_len = msg->msg_controllen;
+ pass->cmsghdr.cmsg_level = SOL_SOCKET;
+ pass->cmsghdr.cmsg_type = SCM_RIGHTS;
+}
+
+#endif /* XTRANS_SEND_FDS */
+
+static int
+TRANS(SocketRead) (XtransConnInfo ciptr, char *buf, int size)
+
+{
+ prmsg (2,"SocketRead(%d,%p,%d)\n", ciptr->fd, buf, size);
#if defined(WIN32)
{
- int ret = send ((SOCKET)ciptr->fd, buf, size, 0);
+ int ret = recv ((SOCKET)ciptr->fd, buf, size, 0);
#ifdef WIN32
if (ret == SOCKET_ERROR) errno = WSAGetLastError();
#endif
return ret;
}
#else
- return write (ciptr->fd, buf, size);
+#if XTRANS_SEND_FDS
+ {
+ struct msghdr msg;
+ struct iovec iov;
+ struct fd_pass pass;
+
+ iov.iov_base = buf;
+ iov.iov_len = size;
+
+ init_msg_recv(&msg, &iov, 1, &pass, MAX_FDS);
+ size = recvmsg(ciptr->fd, &msg, 0);
+ if (size >= 0 && msg.msg_controllen > sizeof (struct cmsghdr)) {
+ if (pass.cmsghdr.cmsg_level == SOL_SOCKET &&
+ pass.cmsghdr.cmsg_type == SCM_RIGHTS &&
+ !((msg.msg_flags & MSG_TRUNC) ||
+ (msg.msg_flags & MSG_CTRUNC)))
+ {
+ int nfd = (msg.msg_controllen - sizeof (struct cmsghdr)) / sizeof (int);
+ int *fd = (int *) CMSG_DATA(&pass.cmsghdr);
+ int i;
+ for (i = 0; i < nfd; i++)
+ appendFd(&ciptr->recv_fds, fd[i], 0);
+ }
+ }
+ return size;
+ }
+#else
+ return read(ciptr->fd, buf, size);
+#endif /* XTRANS_SEND_FDS */
#endif /* WIN32 */
}
-
static int
TRANS(SocketReadv) (XtransConnInfo ciptr, struct iovec *buf, int size)
@@ -2154,11 +2283,65 @@ TRANS(SocketWritev) (XtransConnInfo ciptr, struct iovec *buf, int size)
{
prmsg (2,"SocketWritev(%d,%p,%d)\n", ciptr->fd, buf, size);
+#if XTRANS_SEND_FDS
+ if (ciptr->send_fds)
+ {
+ struct msghdr msg;
+ struct fd_pass pass;
+ int nfd;
+ struct _XtransConnFd *cf;
+ int i;
+
+ nfd = nFd(&ciptr->send_fds);
+ cf = ciptr->send_fds;
+
+ /* Set up fds */
+ for (i = 0; i < nfd; i++) {
+ pass.fd[i] = cf->fd;
+ cf = cf->next;
+ }
+
+ init_msg_send(&msg, buf, size, &pass, nfd);
+ i = sendmsg(ciptr->fd, &msg, 0);
+ if (i > 0)
+ discardFd(&ciptr->send_fds, cf, 0);
+ return i;
+ }
+#endif
return WRITEV (ciptr, buf, size);
}
static int
+TRANS(SocketWrite) (XtransConnInfo ciptr, char *buf, int size)
+
+{
+ prmsg (2,"SocketWrite(%d,%p,%d)\n", ciptr->fd, buf, size);
+
+#if defined(WIN32)
+ {
+ int ret = send ((SOCKET)ciptr->fd, buf, size, 0);
+#ifdef WIN32
+ if (ret == SOCKET_ERROR) errno = WSAGetLastError();
+#endif
+ return ret;
+ }
+#else
+#if XTRANS_SEND_FDS
+ if (ciptr->send_fds)
+ {
+ struct iovec iov;
+
+ iov.iov_base = buf;
+ iov.iov_len = size;
+ return TRANS(SocketWritev)(ciptr, &iov, 1);
+ }
+#endif /* XTRANS_SEND_FDS */
+ return write (ciptr->fd, buf, size);
+#endif /* WIN32 */
+}
+
+static int
TRANS(SocketDisconnect) (XtransConnInfo ciptr)
{
@@ -2211,6 +2394,9 @@ TRANS(SocketUNIXClose) (XtransConnInfo ciptr)
prmsg (2,"SocketUNIXClose(%p,%d)\n", ciptr, ciptr->fd);
+#if XTRANS_SEND_FDS
+ cleanupFds(ciptr);
+#endif
ret = close(ciptr->fd);
if (ciptr->flags
@@ -2239,6 +2425,9 @@ TRANS(SocketUNIXCloseForCloning) (XtransConnInfo ciptr)
prmsg (2,"SocketUNIXCloseForCloning(%p,%d)\n",
ciptr, ciptr->fd);
+#if XTRANS_SEND_FDS
+ cleanupFds(ciptr);
+#endif
ret = close(ciptr->fd);
return ret;
@@ -2293,6 +2482,8 @@ Xtransport TRANS(SocketTCPFuncs) = {
TRANS(SocketWrite),
TRANS(SocketReadv),
TRANS(SocketWritev),
+ TRANS(SocketSendFdInvalid),
+ TRANS(SocketRecvFdInvalid),
TRANS(SocketDisconnect),
TRANS(SocketINETClose),
TRANS(SocketINETClose),
@@ -2333,6 +2524,8 @@ Xtransport TRANS(SocketINETFuncs) = {
TRANS(SocketWrite),
TRANS(SocketReadv),
TRANS(SocketWritev),
+ TRANS(SocketSendFdInvalid),
+ TRANS(SocketRecvFdInvalid),
TRANS(SocketDisconnect),
TRANS(SocketINETClose),
TRANS(SocketINETClose),
@@ -2374,6 +2567,8 @@ Xtransport TRANS(SocketINET6Funcs) = {
TRANS(SocketWrite),
TRANS(SocketReadv),
TRANS(SocketWritev),
+ TRANS(SocketSendFdInvalid),
+ TRANS(SocketRecvFdInvalid),
TRANS(SocketDisconnect),
TRANS(SocketINETClose),
TRANS(SocketINETClose),
@@ -2422,6 +2617,8 @@ Xtransport TRANS(SocketLocalFuncs) = {
TRANS(SocketWrite),
TRANS(SocketReadv),
TRANS(SocketWritev),
+ TRANS(SocketSendFd),
+ TRANS(SocketRecvFd),
TRANS(SocketDisconnect),
TRANS(SocketUNIXClose),
TRANS(SocketUNIXCloseForCloning),
@@ -2476,6 +2673,8 @@ Xtransport TRANS(SocketUNIXFuncs) = {
TRANS(SocketWrite),
TRANS(SocketReadv),
TRANS(SocketWritev),
+ TRANS(SocketSendFd),
+ TRANS(SocketRecvFd),
TRANS(SocketDisconnect),
TRANS(SocketUNIXClose),
TRANS(SocketUNIXCloseForCloning),
--
1.8.4.rc3
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