From 884057f77f0630f1edac87bbce8f4809d40b7e1d Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Thu, 7 Nov 2013 16:47:38 -0800 Subject: [PATCH] Use the CMSG macros for getting at our FDs. The manual stuff was only working on 32-bit userspace -- struct alignment was breaking the estimates on 64. It also fixes trying to memcpy nfd bytes instead of ints. --- src/xcb_in.c | 35 ++++++++++++++++++++--------------- 1 file changed, 20 insertions(+), 15 deletions(-) diff --git a/src/xcb_in.c b/src/xcb_in.c index 839f615..901929f 100644 --- a/src/xcb_in.c +++ b/src/xcb_in.c @@ -888,17 +888,14 @@ int _xcb_in_read(xcb_connection_t *c) .iov_base = c->in.queue + c->in.queue_len, .iov_len = sizeof(c->in.queue) - c->in.queue_len, }; - struct { - struct cmsghdr cmsghdr; - int fd[XCB_MAX_PASS_FD]; - } fds; + char fd_data[CMSG_SPACE(XCB_MAX_PASS_FD * sizeof(int))]; struct msghdr msg = { .msg_name = NULL, .msg_namelen = 0, .msg_iov = &iov, .msg_iovlen = 1, - .msg_control = &fds, - .msg_controllen = sizeof (struct cmsghdr) + sizeof(int) * (XCB_MAX_PASS_FD - c->in.in_fd.nfd), + .msg_control = fd_data, + .msg_controllen = sizeof(fd_data), }; n = recvmsg(c->fd, &msg, 0); @@ -916,16 +913,24 @@ int _xcb_in_read(xcb_connection_t *c) #endif if(n > 0) { #if HAVE_SENDMSG - if (msg.msg_controllen > sizeof (struct cmsghdr)) - { - if (fds.cmsghdr.cmsg_level == SOL_SOCKET && - fds.cmsghdr.cmsg_type == SCM_RIGHTS) + struct cmsghdr *hdr; + + for (hdr = CMSG_FIRSTHDR(&msg); + hdr != NULL; + hdr = CMSG_NXTHDR(&msg, hdr)) + { + if (hdr->cmsg_level == SOL_SOCKET && + hdr->cmsg_type == SCM_RIGHTS) { - int nfd = (msg.msg_controllen - sizeof (struct cmsghdr)) / sizeof (int); - memmove(&c->in.in_fd.fd[c->in.in_fd.nfd], - fds.fd, - nfd); - c->in.in_fd.nfd += nfd; + /* Weird, there's a CMSG_LEN to go from size to + * cmsg_len, but not the other way around. + */ + int nfd = ((CMSG_LEN(sizeof(int)) - hdr->cmsg_len) / + sizeof(int)) + 1; + unsigned char *fds = CMSG_DATA(hdr); + memcpy(&c->in.in_fd.fd[c->in.in_fd.nfd], fds, + nfd * sizeof(int)); + c->in.in_fd.nfd += nfd; } } #endif -- 1.8.4.rc3