[PATCH 5/8] Add support for receiving fds in replies
Keith Packard
keithp at keithp.com
Wed Nov 6 19:45:42 PST 2013
Requests signal which replies will have fds, and the replies report
how many fds they expect in byte 1.
Signed-off-by: Keith Packard <keithp at keithp.com>
---
src/c_client.py | 65 ++++++++++++++++++++++++++++++++++---
src/xcb_in.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
src/xcbext.h | 4 ++-
src/xcbint.h | 4 +++
4 files changed, 163 insertions(+), 9 deletions(-)
diff --git a/src/c_client.py b/src/c_client.py
index cc26f72..7280004 100644
--- a/src/c_client.py
+++ b/src/c_client.py
@@ -303,6 +303,7 @@ def _c_type_setup(self, name, postfix):
self.c_reply_name = _n(name + ('reply',))
self.c_reply_type = _t(name + ('reply',))
self.c_cookie_type = _t(name + ('cookie',))
+ self.c_reply_fds_name = _n(name + ('reply_fds',))
self.need_aux = False
self.need_serialize = False
@@ -1835,7 +1836,7 @@ def c_union(self, name):
_c_complex(self)
_c_iterator(self, name)
-def _c_request_helper(self, name, cookie_type, void, regular, aux=False):
+def _c_request_helper(self, name, cookie_type, void, regular, aux=False, reply_fds=False):
'''
Declares a request function.
'''
@@ -1864,6 +1865,12 @@ def _c_request_helper(self, name, cookie_type, void, regular, aux=False):
# What flag is passed to xcb_request
func_flags = '0' if (void and regular) or (not void and not regular) else 'XCB_REQUEST_CHECKED'
+ if reply_fds:
+ if func_flags == '0':
+ func_flags = 'XCB_REQUEST_REPLY_FDS'
+ else:
+ func_flags = func_flags + '|XCB_REQUEST_REPLY_FDS'
+
# Global extension id variable or NULL for xproto
func_ext_global = '&' + _ns.c_ext_global_name if _ns.is_ext else '0'
@@ -2256,6 +2263,51 @@ def _c_reply(self, name):
_c('}')
+def _c_reply_has_fds(self):
+ for field in self.fields:
+ if field.isfd:
+ return True
+ return False
+
+def _c_reply_fds(self, name):
+ '''
+ Declares the function that returns fds related to the reply.
+ '''
+ spacing1 = ' ' * (len(self.c_reply_type) - len('xcb_connection_t'))
+ spacing3 = ' ' * (len(self.c_reply_fds_name) + 2)
+ _h('')
+ _h('/**')
+ _h(' * Return the reply fds')
+ _h(' * @param c The connection')
+ _h(' * @param reply The reply')
+ _h(' *')
+ _h(' * Returns the array of reply fds of the request asked by')
+ _h(' * ')
+ _h(' * The returned value must be freed by the caller using free().')
+ _h(' */')
+ _c('')
+ _hc('')
+ _hc('/*****************************************************************************')
+ _hc(' **')
+ _hc(' ** int * %s', self.c_reply_fds_name)
+ _hc(' ** ')
+ _hc(' ** @param xcb_connection_t%s *c', spacing1)
+ _hc(' ** @param %s *reply', self.c_reply_type)
+ _hc(' ** @returns int *')
+ _hc(' **')
+ _hc(' *****************************************************************************/')
+ _hc(' ')
+ _hc('int *')
+ _hc('%s (xcb_connection_t%s *c /**< */,', self.c_reply_fds_name, spacing1)
+ _h('%s%s *reply /**< */);', spacing3, self.c_reply_type)
+ _c('%s%s *reply /**< */)', spacing3, self.c_reply_type)
+ _c('{')
+
+ _c(' return xcb_get_reply_fds(c, reply, sizeof(%s) + 4 * reply->length);', self.c_reply_type)
+
+ _c('}')
+
+
def _c_opcode(name, opcode):
'''
Declares the opcode define for requests, events, and errors.
@@ -2816,14 +2868,17 @@ def c_request(self, name):
# Reply structure definition
_c_complex(self.reply)
# Request prototypes
- _c_request_helper(self, name, self.c_cookie_type, False, True)
- _c_request_helper(self, name, self.c_cookie_type, False, False)
+ has_fds = _c_reply_has_fds(self.reply)
+ _c_request_helper(self, name, self.c_cookie_type, False, True, False, has_fds)
+ _c_request_helper(self, name, self.c_cookie_type, False, False, False, has_fds)
if self.need_aux:
- _c_request_helper(self, name, self.c_cookie_type, False, True, True)
- _c_request_helper(self, name, self.c_cookie_type, False, False, True)
+ _c_request_helper(self, name, self.c_cookie_type, False, True, True, has_fds)
+ _c_request_helper(self, name, self.c_cookie_type, False, False, True, has_fds)
# Reply accessors
_c_accessors(self.reply, name + ('reply',), name)
_c_reply(self, name)
+ if has_fds:
+ _c_reply_fds(self, name)
else:
# Request prototypes
_c_request_helper(self, name, 'xcb_void_cookie_t', True, False)
diff --git a/src/xcb_in.c b/src/xcb_in.c
index ac4d284..0a78ae6 100644
--- a/src/xcb_in.c
+++ b/src/xcb_in.c
@@ -91,11 +91,26 @@ static void remove_finished_readers(reader_list **prev_reader, uint64_t complete
}
}
+#if HAVE_SENDMSG
+static int read_fds(xcb_connection_t *c, int *fds, int nfd)
+{
+ int *ifds = &c->in.in_fd.fd[c->in.in_fd.ifd];
+ int infd = c->in.in_fd.nfd - c->in.in_fd.ifd;
+
+ if (nfd > infd)
+ return 0;
+ memcpy(fds, ifds, nfd * sizeof (int));
+ c->in.in_fd.ifd += nfd;
+ return 1;
+}
+#endif
+
static int read_packet(xcb_connection_t *c)
{
xcb_generic_reply_t genrep;
uint64_t length = 32;
uint64_t eventlength = 0; /* length after first 32 bytes for GenericEvents */
+ int nfd = 0; /* Number of file descriptors attached to the reply */
uint64_t bufsize;
void *buf;
pending_reply *pend = 0;
@@ -165,13 +180,18 @@ static int read_packet(xcb_connection_t *c)
genrep.length = p[2] * p[3] * 2;
}
length += genrep.length * 4;
+
+ /* XXX a bit of a hack -- we "know" that all FD replys place
+ * the number of fds in the pad0 byte */
+ if (pend && pend->flags & XCB_REQUEST_REPLY_FDS)
+ nfd = genrep.pad0;
}
/* XGE events may have sizes > 32 */
if ((genrep.response_type & 0x7f) == XCB_XGE_EVENT)
eventlength = genrep.length * 4;
- bufsize = length + eventlength +
+ bufsize = length + eventlength + nfd * sizeof(int) +
(genrep.response_type == XCB_REPLY ? 0 : sizeof(uint32_t));
if (bufsize < INT32_MAX)
buf = malloc((size_t) bufsize);
@@ -199,6 +219,17 @@ static int read_packet(xcb_connection_t *c)
}
}
+#if HAVE_SENDMSG
+ if (nfd)
+ {
+ if (!read_fds(c, (int *) &((char *) buf)[length], nfd))
+ {
+ free(buf);
+ return 0;
+ }
+ }
+#endif
+
if(pend && (pend->flags & XCB_REQUEST_DISCARD_REPLY))
{
free(buf);
@@ -432,6 +463,11 @@ void *xcb_wait_for_reply(xcb_connection_t *c, unsigned int request, xcb_generic_
return ret;
}
+int *xcb_get_reply_fds(xcb_connection_t *c, void *reply, size_t reply_size)
+{
+ return (int *) (&((char *) reply)[reply_size]);
+}
+
static void insert_pending_discard(xcb_connection_t *c, pending_reply **prev_next, uint64_t seq)
{
pending_reply *pend;
@@ -666,11 +702,68 @@ void _xcb_in_replies_done(xcb_connection_t *c)
int _xcb_in_read(xcb_connection_t *c)
{
- int n = recv(c->fd, c->in.queue + c->in.queue_len, sizeof(c->in.queue) - c->in.queue_len, 0);
- if(n > 0)
+ int n;
+
+#if HAVE_SENDMSG
+ struct iovec iov = {
+ .iov_base = c->in.queue + c->in.queue_len,
+ .iov_len = sizeof(c->in.queue) - c->in.queue_len,
+ };
+ struct msghdr msg = {
+ .msg_name = NULL,
+ .msg_namelen = 0,
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
+ .msg_control = &c->in.in_fd,
+ .msg_controllen = sizeof (struct cmsghdr) + sizeof (int) * XCB_MAX_PASS_FD,
+ };
+ n = recvmsg(c->fd, &msg, 0);
+
+ /* Check for truncation errors. Only MSG_CTRUNC is
+ * probably possible here, which would indicate that
+ * the sender tried to transmit more than XCB_MAX_PASS_FD
+ * file descriptors.
+ */
+ if (msg.msg_flags & (MSG_TRUNC|MSG_CTRUNC)) {
+ _xcb_conn_shutdown(c, XCB_CONN_ERROR);
+ return 0;
+ }
+#else
+ n = recv(c->fd, c->in.queue + c->in.queue_len, sizeof(c->in.queue) - c->in.queue_len, 0);
+#endif
+ if(n > 0) {
+#if HAVE_SENDMSG
+ if (msg.msg_controllen > sizeof (struct cmsghdr))
+ {
+ if (c->in.in_fd.cmsghdr.cmsg_level == SOL_SOCKET &&
+ c->in.in_fd.cmsghdr.cmsg_type == SCM_RIGHTS &&
+ !((msg.msg_flags & MSG_TRUNC) ||
+ (msg.msg_flags & MSG_CTRUNC)))
+ {
+ c->in.in_fd.nfd = (msg.msg_controllen - sizeof (struct cmsghdr)) / sizeof (int);
+ }
+ }
+#endif
c->in.queue_len += n;
+ }
while(read_packet(c))
/* empty */;
+#if HAVE_SENDMSG
+ c->in.in_fd.nfd -= c->in.in_fd.ifd;
+ c->in.in_fd.ifd = 0;
+
+ /* If we have any left-over file descriptors, then
+ * the server sent some that we weren't expecting.
+ * Close them and mark the connection as broken;
+ */
+ if (c->in.in_fd.nfd != 0) {
+ int i;
+ for (i = 0; i < c->in.in_fd.nfd; i++)
+ close(c->in.in_fd.fd[i]);
+ _xcb_conn_shutdown(c, XCB_CONN_ERROR);
+ return 0;
+ }
+#endif
#ifndef _WIN32
if((n > 0) || (n < 0 && errno == EAGAIN))
#else
diff --git a/src/xcbext.h b/src/xcbext.h
index 44030c3..1eb1be7 100644
--- a/src/xcbext.h
+++ b/src/xcbext.h
@@ -54,7 +54,8 @@ typedef struct {
enum xcb_send_request_flags_t {
XCB_REQUEST_CHECKED = 1 << 0,
XCB_REQUEST_RAW = 1 << 1,
- XCB_REQUEST_DISCARD_REPLY = 1 << 2
+ XCB_REQUEST_DISCARD_REPLY = 1 << 2,
+ XCB_REQUEST_REPLY_FDS = 1 << 3
};
unsigned int xcb_send_request(xcb_connection_t *c, int flags, struct iovec *vector, const xcb_protocol_request_t *request);
@@ -91,6 +92,7 @@ int xcb_writev(xcb_connection_t *c, struct iovec *vector, int count, uint64_t re
void *xcb_wait_for_reply(xcb_connection_t *c, unsigned int request, xcb_generic_error_t **e);
int xcb_poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error);
+int *xcb_get_reply_fds(xcb_connection_t *c, void *reply, size_t replylen);
/* xcb_util.c */
diff --git a/src/xcbint.h b/src/xcbint.h
index b2dfed3..bbc5398 100644
--- a/src/xcbint.h
+++ b/src/xcbint.h
@@ -88,6 +88,7 @@ typedef struct _xcb_fd {
struct cmsghdr cmsghdr;
int fd[XCB_MAX_PASS_FD];
int nfd;
+ int ifd;
} _xcb_fd;
#endif
@@ -146,6 +147,9 @@ typedef struct _xcb_in {
struct pending_reply *pending_replies;
struct pending_reply **pending_replies_tail;
+#if HAVE_SENDMSG
+ _xcb_fd in_fd;
+#endif
} _xcb_in;
int _xcb_in_init(_xcb_in *in);
--
1.8.4.2
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