minix/servers/hgfs/libhgfs/rpc.c

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/* Part of libhgfs - (c) 2009, D.C. van Moolenbroek */
#include "inc.h"
PUBLIC char rpc_buf[RPC_BUF_SIZE];
PUBLIC char *rpc_ptr;
PRIVATE struct channel rpc_chan;
/*===========================================================================*
* rpc_open *
*===========================================================================*/
PUBLIC int rpc_open()
{
/* Open a HGFS RPC backdoor channel to the VMware host, and make sure that it
* is working. Return OK upon success, or a negative error code otherwise.
*/
int r;
if ((r = channel_open(&rpc_chan, CH_OUT)) != OK)
return r;
r = rpc_test();
if (r != OK && r != EAGAIN)
channel_close(&rpc_chan);
return r;
}
/*===========================================================================*
* rpc_query *
*===========================================================================*/
PUBLIC int rpc_query()
{
/* Send a HGFS RPC query over the backdoor channel. Return OK upon success, or
* a negative error code otherwise; EAGAIN is returned if shared folders are
* disabled. In general, we make the assumption that the sender (= VMware)
* speaks the protocol correctly. Hence, the callers of this function do not
* check for lengths.
*/
int r, len, id, err;
len = RPC_LEN;
/* A more robust version of this call could reopen the channel and
* retry the request upon low-level failure.
*/
r = channel_send(&rpc_chan, rpc_buf, len);
if (r < 0) return r;
r = channel_recv(&rpc_chan, rpc_buf, sizeof(rpc_buf));
if (r < 0) return r;
if (r < 2 || (len > 2 && r < 10)) return EIO;
RPC_RESET;
if (RPC_NEXT8 != '1') return EAGAIN;
if (RPC_NEXT8 != ' ') return EAGAIN;
if (len <= 2) return OK;
id = RPC_NEXT32;
err = RPC_NEXT32;
return error_convert(err);
}
/*===========================================================================*
* rpc_test *
*===========================================================================*/
PUBLIC int rpc_test()
{
/* Test whether HGFS communication is working. Return OK on success, EAGAIN if
* shared folders are disabled, or another negative error code upon error.
*/
RPC_RESET;
RPC_NEXT8 = 'f';
RPC_NEXT8 = ' ';
return rpc_query();
}
/*===========================================================================*
* rpc_close *
*===========================================================================*/
PUBLIC void rpc_close()
{
/* Close the HGFS RPC backdoor channel.
*/
channel_close(&rpc_chan);
}