1/* Connect implementation
2   Copyright (C) 2014 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3.  If not see
18<http://www.gnu.org/licenses/>.  */
19
20#include <cc1plugin-config.h>
21#include <string>
22#include <unistd.h>
23#include <sys/types.h>
24#include <string.h>
25#include <errno.h>
26#include "marshall.hh"
27#include "connection.hh"
28#include "rpc.hh"
29
30cc1_plugin::connection::~connection ()
31{
32}
33
34void
35cc1_plugin::connection::print (const char *)
36{
37}
38
39cc1_plugin::status
40cc1_plugin::connection::send (char c)
41{
42  if (write (m_fd, &c, 1) != 1)
43    return FAIL;
44  return OK;
45}
46
47cc1_plugin::status
48cc1_plugin::connection::send (const void *buf, int len)
49{
50  if (write (m_fd, buf, len) != len)
51    return FAIL;
52  return OK;
53}
54
55cc1_plugin::status
56cc1_plugin::connection::require (char c)
57{
58  char result;
59
60  if (read (m_fd, &result, 1) != 1
61      || result != c)
62    return FAIL;
63
64  return OK;
65}
66
67cc1_plugin::status
68cc1_plugin::connection::get (void *buf, int len)
69{
70  if (read (m_fd, buf, len) != len)
71    return FAIL;
72  return OK;
73}
74
75cc1_plugin::status
76cc1_plugin::connection::do_wait (bool want_result)
77{
78  while (true)
79    {
80      char result;
81      fd_set read_set;
82
83      FD_ZERO (&read_set);
84      FD_SET (m_fd, &read_set);
85      if (m_aux_fd != -1)
86	FD_SET (m_aux_fd, &read_set);
87
88      int nfds = select (FD_SETSIZE, &read_set, NULL, NULL, NULL);
89      if (nfds == -1)
90	{
91	  if (errno == EINTR)
92	    continue;
93	  return FAIL;
94	}
95
96      // We have to check the stderr fd first, to avoid a possible
97      // blocking scenario when do_wait is called reentrantly.  In
98      // such a call, if we handle the primary fd first, then we may
99      // re-enter this function, read from gcc's stderr, causing the
100      // outer invocation of this function to block when trying to
101      // read.
102      if (m_aux_fd != -1 && FD_ISSET (m_aux_fd, &read_set))
103	{
104	  char buf[1024];
105	  int n = read (m_aux_fd, buf, sizeof (buf) - 1);
106	  if (n < 0)
107	    return FAIL;
108	  if (n > 0)
109	    {
110	      buf[n] = '\0';
111	      print (buf);
112	    }
113	}
114
115      if (FD_ISSET (m_fd, &read_set))
116	{
117	  int n = read (m_fd, &result, 1);
118	  if (n == 0)
119	    return want_result ? FAIL : OK;
120	  if (n != 1)
121	    return FAIL;
122
123	  switch (result)
124	    {
125	    case 'R':
126	      // The reply is ready; the caller will unmarshall it.
127	      return want_result ? OK : FAIL;
128
129	    case 'Q':
130	      // While waiting for a reply, the other side made a method
131	      // call.
132	      {
133		// Use an argument_wrapper here to simplify management
134		// of the string's lifetime.
135		argument_wrapper<char *> method_name;
136
137		if (!method_name.unmarshall (this))
138		  return FAIL;
139
140		callback_ftype *callback
141		  = m_callbacks.find_callback (method_name);
142		// The call to CALLBACK is where we may end up in a
143		// reentrant call.
144		if (callback == NULL || !callback (this))
145		  return FAIL;
146	      }
147	      break;
148
149	    default:
150	      return FAIL;
151	    }
152	}
153    }
154}
155