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Add SCM_RIGHTS support to unix socket character devices

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If a file descriptor is passed via a message with SCM_RIGHTS ancillary
data on a unix socket, store the file descriptor for use in the
chr_read() handler. Close the file descriptor if it was not used.

The qemu_chr_get_msgfd() API provides access to the passed descriptor.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Mark McLoughlin 2009-07-22 09:11:39 +01:00 committed by Anthony Liguori
parent 9977c8943a
commit 7d1740590b
2 changed files with 56 additions and 1 deletions
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55
qemu-char.c
View file

@ -168,6 +168,11 @@ void qemu_chr_read(CharDriverState *s, uint8_t *buf, int len)
s->chr_read(s->handler_opaque, buf, len);
}
int qemu_chr_get_msgfd(CharDriverState *s)
{
return s->get_msgfd ? s->get_msgfd(s) : -1;
}
void qemu_chr_accept_input(CharDriverState *s)
{
if (s->chr_accept_input)
@ -1832,6 +1837,7 @@ typedef struct {
int do_telnetopt;
int do_nodelay;
int is_unix;
int msgfd;
} TCPCharDriver;
static void tcp_chr_accept(void *opaque);
@ -1907,20 +1913,61 @@ static void tcp_chr_process_IAC_bytes(CharDriverState *chr,
*size = j;
}
static int tcp_get_msgfd(CharDriverState *chr)
{
TCPCharDriver *s = chr->opaque;
return s->msgfd;
}
#ifndef WIN32
static void unix_process_msgfd(CharDriverState *chr, struct msghdr *msg)
{
TCPCharDriver *s = chr->opaque;
struct cmsghdr *cmsg;
for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
int fd;
if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
cmsg->cmsg_level != SOL_SOCKET ||
cmsg->cmsg_type != SCM_RIGHTS)
continue;
fd = *((int *)CMSG_DATA(cmsg));
if (fd < 0)
continue;
if (s->msgfd != -1)
close(s->msgfd);
s->msgfd = fd;
}
}
static ssize_t tcp_chr_recv(CharDriverState *chr, char *buf, size_t len)
{
TCPCharDriver *s = chr->opaque;
struct msghdr msg = { 0, };
struct iovec iov[1];
union {
struct cmsghdr cmsg;
char control[CMSG_SPACE(sizeof(int))];
} msg_control;
ssize_t ret;
iov[0].iov_base = buf;
iov[0].iov_len = len;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
msg.msg_control = &msg_control;
msg.msg_controllen = sizeof(msg_control);
return recvmsg(s->fd, &msg, 0);
ret = recvmsg(s->fd, &msg, 0);
if (ret > 0 && s->is_unix)
unix_process_msgfd(chr, &msg);
return ret;
}
#else
static ssize_t tcp_chr_recv(CharDriverState *chr, char *buf, size_t len)
@ -1957,6 +2004,10 @@ static void tcp_chr_read(void *opaque)
tcp_chr_process_IAC_bytes(chr, s, buf, &size);
if (size > 0)
qemu_chr_read(chr, buf, size);
if (s->msgfd != -1) {
close(s->msgfd);
s->msgfd = -1;
}
}
}
@ -2118,12 +2169,14 @@ static CharDriverState *qemu_chr_open_tcp(const char *host_str,
s->connected = 0;
s->fd = -1;
s->listen_fd = -1;
s->msgfd = -1;
s->is_unix = is_unix;
s->do_nodelay = do_nodelay && !is_unix;
chr->opaque = s;
chr->chr_write = tcp_chr_write;
chr->chr_close = tcp_chr_close;
chr->get_msgfd = tcp_get_msgfd;
if (is_listen) {
s->listen_fd = fd;

2
qemu-char.h
View file

@ -51,6 +51,7 @@ struct CharDriverState {
int (*chr_write)(struct CharDriverState *s, const uint8_t *buf, int len);
void (*chr_update_read_handler)(struct CharDriverState *s);
int (*chr_ioctl)(struct CharDriverState *s, int cmd, void *arg);
int (*get_msgfd)(struct CharDriverState *s);
IOEventHandler *chr_event;
IOCanRWHandler *chr_can_read;
IOReadHandler *chr_read;
@ -81,6 +82,7 @@ void qemu_chr_reset(CharDriverState *s);
void qemu_chr_initial_reset(void);
int qemu_chr_can_read(CharDriverState *s);
void qemu_chr_read(CharDriverState *s, uint8_t *buf, int len);
int qemu_chr_get_msgfd(CharDriverState *s);
void qemu_chr_accept_input(CharDriverState *s);
void qemu_chr_info(Monitor *mon);