On Wed, Jan 08, 2014 at 05:12:51PM +0800, Lei Li wrote: > Signed-off-by: Lei Li <li...@linux.vnet.ibm.com> > --- > include/qemu/fd-exchange.h | 25 +++++++++++ > util/Makefile.objs | 1 + > util/qemu-fd-exchange.c | 97 > ++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 123 insertions(+), 0 deletions(-) > create mode 100644 include/qemu/fd-exchange.h > create mode 100644 util/qemu-fd-exchange.c > > diff --git a/include/qemu/fd-exchange.h b/include/qemu/fd-exchange.h > new file mode 100644 > index 0000000..6929026 > --- /dev/null > +++ b/include/qemu/fd-exchange.h > @@ -0,0 +1,25 @@ > +/* > + * Internel common methods for exchange of FD > + * > + * This work is licensed under the terms of the GNU GPL, version 2. See > + * the COPYING file in the top-level directory. > + * > + */ > + > +#ifndef FD_EXCHANGE_H > +#define FD_EXCHANGE_H > + > +#include <sys/socket.h> > + > +union MsgControl { > + struct cmsghdr cmsg; > + char control[CMSG_SPACE(sizeof(int))]; > +}; > + > +ssize_t qemu_send_with_fd(int sockfd, int passed_fd, > + const void *buf, size_t len); > + > +ssize_t qemu_recv_with_fd(int sockfd, int *passed_fd, > + void *buf, size_t len); > + > +#endif > diff --git a/util/Makefile.objs b/util/Makefile.objs > index af3e5cb..2fb42bf 100644 > --- a/util/Makefile.objs > +++ b/util/Makefile.objs > @@ -13,3 +13,4 @@ util-obj-y += hexdump.o > util-obj-y += crc32c.o > util-obj-y += throttle.o > util-obj-y += getauxval.o > +util-obj-y += qemu-fd-exchange.o > diff --git a/util/qemu-fd-exchange.c b/util/qemu-fd-exchange.c > new file mode 100644 > index 0000000..70a3206 > --- /dev/null > +++ b/util/qemu-fd-exchange.c > @@ -0,0 +1,97 @@ > +/* > + * Internel common methods for exchange of FD > + * > + * This work is licensed under the terms of the GNU GPL, version 2. See > + * the COPYING file in the top-level directory. > + * > + */ > + > +#include "qemu/fd-exchange.h" > +#include "qemu-common.h" > + > + > +ssize_t qemu_send_with_fd(int sockfd, int passed_fd, > + const void *buf, size_t len) > +{ > + struct msghdr msg; > + struct iovec iov; > + struct cmsghdr *cmsg; > + union MsgControl msg_control; > + int retval; > + > + iov.iov_base = (int *)buf; > + iov.iov_len = len; > + > + memset(&msg, 0, sizeof(msg)); > + msg.msg_iov = &iov; > + msg.msg_iovlen = len; > + msg.msg_control = &msg_control; > + msg.msg_controllen = sizeof(msg_control); > + > + if (passed_fd < 0) { > + *(int *)buf = passed_fd;
You are casting 'char *buf' to an 'int *' but many of the callers only pass in a pointer to a 'char buf[1]'. So you are overflowing the array and also likely causing alignment violations on ARM platforms. > + } else { > + msg.msg_control = &msg_control; > + msg.msg_controllen = sizeof(msg_control); > + > + cmsg = &msg_control.cmsg; > + cmsg->cmsg_len = CMSG_LEN(sizeof(passed_fd)); > + cmsg->cmsg_level = SOL_SOCKET; > + cmsg->cmsg_type = SCM_RIGHTS; > + memcpy(CMSG_DATA(cmsg), &passed_fd, sizeof(passed_fd)); > + > + } > + > + do { > + retval = sendmsg(sockfd, &msg, 0); > + } while (retval < 0 && errno == EINTR); > + > + return retval; > +} > + > +ssize_t qemu_recv_with_fd(int sockfd, int *passed_fd, > + void *buf, size_t len) > +{ > + struct iovec iov; > + struct msghdr msg; > + struct cmsghdr *cmsg; > + union MsgControl msg_control; > + int retval; > + int data = *(int *)buf; > + > + iov.iov_base = buf; > + iov.iov_len = len; > + > + memset(&msg, 0, sizeof(msg)); > + msg.msg_iov = &iov; > + msg.msg_iovlen = 1; > + msg.msg_control = &msg_control; > + msg.msg_controllen = sizeof(msg_control); > + > + do { > + retval = recvmsg(sockfd, &msg, 0); > + } while (retval < 0 && errno == EINTR); > + > + if (retval <= 0) { > + return retval; > + } > + > + if (data != *(int *)buf) { > + *passed_fd = data; > + return 0; > + } Again cast issues > + > + for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { > + if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) || > + cmsg->cmsg_level != SOL_SOCKET || > + cmsg->cmsg_type != SCM_RIGHTS) { > + continue; > + } > + > + memcpy(passed_fd, CMSG_DATA(cmsg), sizeof(*passed_fd)); > + return 0; > + } > + > + *passed_fd = -ENFILE; > + return retval; > +} > -- Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|