Commit d39aac7a authored by Nikolay Nikolaev's avatar Nikolay Nikolaev Committed by Michael S. Tsirkin
Browse files

Add chardev API qemu_chr_fe_set_msgfds 



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: default avatarAntonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: default avatarNikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 7b0bfdf5

include/sysemu/char.h

+14 −0
Original line number Diff line number Diff line
@@ -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:

 *

qemu-char.c

+87 −1
Original line number Diff line number Diff line
@@ -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) {

#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;