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Add chardev API qemu_chr_fe_set_msgfds

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This will set an array of file descriptors to the internal structures.
The next time a message is send the array will be send as ancillary
data. This feature works on the UNIX domain socket backend only.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Nikolay Nikolaev 2014-05-27 15:04:02 +03:00 committed by Michael S. Tsirkin
parent 7b0bfdf52d
commit d39aac7aac
2 changed files with 101 additions and 1 deletions
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14
include/sysemu/char.h
View File

@ -62,6 +62,7 @@ struct CharDriverState {
void (*chr_update_read_handler)(struct CharDriverState *s);
int (*chr_ioctl)(struct CharDriverState *s, int cmd, void *arg);
int (*get_msgfd)(struct CharDriverState *s);
int (*set_msgfds)(struct CharDriverState *s, int *fds, int num);
int (*chr_add_client)(struct CharDriverState *chr, int fd);
IOEventHandler *chr_event;
IOCanReadHandler *chr_can_read;
@ -228,6 +229,19 @@ int qemu_chr_fe_ioctl(CharDriverState *s, int cmd, void *arg);
*/
int qemu_chr_fe_get_msgfd(CharDriverState *s);
/**
* @qemu_chr_fe_set_msgfds:
*
* For backends capable of fd passing, set an array of fds to be passed with
* the next send operation.
* A subsequent call to this function before calling a write function will
* result in overwriting the fd array with the new value without being send.
* Upon writing the message the fd array is freed.
*
* Returns: -1 if fd passing isn't supported.
*/
int qemu_chr_fe_set_msgfds(CharDriverState *s, int *fds, int num);
/**
* @qemu_chr_fe_claim:
*

88
qemu-char.c
View File

@ -207,6 +207,11 @@ int qemu_chr_fe_get_msgfd(CharDriverState *s)
return s->get_msgfd ? s->get_msgfd(s) : -1;
}
int qemu_chr_fe_set_msgfds(CharDriverState *s, int *fds, int num)
{
return s->set_msgfds ? s->set_msgfds(s, fds, num) : -1;
}
int qemu_chr_add_client(CharDriverState *s, int fd)
{
return s->chr_add_client ? s->chr_add_client(s, fd) : -1;
@ -2333,15 +2338,71 @@ typedef struct {
int do_nodelay;
int is_unix;
int msgfd;
int *write_msgfds;
int write_msgfds_num;
} TCPCharDriver;
static gboolean tcp_chr_accept(GIOChannel *chan, GIOCondition cond, void *opaque);
#ifndef _WIN32
static int unix_send_msgfds(CharDriverState *chr, const uint8_t *buf, int len)
{
TCPCharDriver *s = chr->opaque;
struct msghdr msgh;
struct iovec iov;
int r;
size_t fd_size = s->write_msgfds_num * sizeof(int);
char control[CMSG_SPACE(fd_size)];
struct cmsghdr *cmsg;
memset(&msgh, 0, sizeof(msgh));
memset(control, 0, sizeof(control));
/* set the payload */
iov.iov_base = (uint8_t *) buf;
iov.iov_len = len;
msgh.msg_iov = &iov;
msgh.msg_iovlen = 1;
msgh.msg_control = control;
msgh.msg_controllen = sizeof(control);
cmsg = CMSG_FIRSTHDR(&msgh);
cmsg->cmsg_len = CMSG_LEN(fd_size);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
memcpy(CMSG_DATA(cmsg), s->write_msgfds, fd_size);
do {
r = sendmsg(s->fd, &msgh, 0);
} while (r < 0 && errno == EINTR);
/* free the written msgfds, no matter what */
if (s->write_msgfds_num) {
g_free(s->write_msgfds);
s->write_msgfds = 0;
s->write_msgfds_num = 0;
}
return r;
}
#endif
static int tcp_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
{
TCPCharDriver *s = chr->opaque;
if (s->connected) {
return io_channel_send(s->chan, buf, len);
#ifndef _WIN32
if (s->is_unix && s->write_msgfds_num) {
return unix_send_msgfds(chr, buf, len);
} else
#endif
{
return io_channel_send(s->chan, buf, len);
}
} else {
/* XXX: indicate an error ? */
return len;
@ -2416,6 +2477,25 @@ static int tcp_get_msgfd(CharDriverState *chr)
return fd;
}
static int tcp_set_msgfds(CharDriverState *chr, int *fds, int num)
{
TCPCharDriver *s = chr->opaque;
/* clear old pending fd array */
if (s->write_msgfds) {
g_free(s->write_msgfds);
}
if (num) {
s->write_msgfds = g_malloc(num * sizeof(int));
memcpy(s->write_msgfds, fds, num * sizeof(int));
}
s->write_msgfds_num = num;
return 0;
}
#ifndef _WIN32
static void unix_process_msgfd(CharDriverState *chr, struct msghdr *msg)
{
@ -2683,6 +2763,9 @@ static void tcp_chr_close(CharDriverState *chr)
}
closesocket(s->listen_fd);
}
if (s->write_msgfds_num) {
g_free(s->write_msgfds);
}
g_free(s);
qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
}
@ -2712,6 +2795,8 @@ static CharDriverState *qemu_chr_open_socket_fd(int fd, bool do_nodelay,
s->fd = -1;
s->listen_fd = -1;
s->msgfd = -1;
s->write_msgfds = 0;
s->write_msgfds_num = 0;
chr->filename = g_malloc(256);
switch (ss.ss_family) {
@ -2743,6 +2828,7 @@ static CharDriverState *qemu_chr_open_socket_fd(int fd, bool do_nodelay,
chr->chr_sync_read = tcp_chr_sync_read;
chr->chr_close = tcp_chr_close;
chr->get_msgfd = tcp_get_msgfd;
chr->set_msgfds = tcp_set_msgfds;
chr->chr_add_client = tcp_chr_add_client;
chr->chr_add_watch = tcp_chr_add_watch;
chr->chr_update_read_handler = tcp_chr_update_read_handler;