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Re: [Qemu-devel] [PATCH 1/6] qemu-fd-exchange: provide common methods fo
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH 1/6] qemu-fd-exchange: provide common methods for exchange fd |
Date: |
Fri, 17 Jan 2014 10:02:02 +0000 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Wed, Jan 08, 2014 at 05:12:51PM +0800, Lei Li wrote:
> Signed-off-by: Lei Li <address@hidden>
> ---
> 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
--
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- [Qemu-devel] [PATCH resend 0/6 RFC] Provide common methods for exchange FD, Lei Li, 2014/01/08
- [Qemu-devel] [PATCH 1/6] qemu-fd-exchange: provide common methods for exchange fd, Lei Li, 2014/01/08
- [Qemu-devel] [PATCH 2/6] qemu-bridge-helper: replace send_fd with qemu_send_with_fd, Lei Li, 2014/01/08
- [Qemu-devel] [PATCH 4/6] virtfs-proxy-helper: replace send_fd with qemu_send_with_fd, Lei Li, 2014/01/08
- [Qemu-devel] [PATCH 3/6] net/tap: replace recv_fd with qemu_recv_with_fd, Lei Li, 2014/01/08
- [Qemu-devel] [PATCH 5/6] virtio-9p-proxy: replace v9fs_receivefd with qemu_recv_with_fd, Lei Li, 2014/01/08
- [Qemu-devel] [PATCH 6/6] migration-local: replace send_pipefd with qemu_send_with_fd, Lei Li, 2014/01/08