connection.cc revision 1.1.1.8 
1/* Connect implementation
2   Copyright (C) 2014-2022 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::status
31cc1_plugin::connection::send (char c)
32{
33  if (write (m_fd, &c, 1) != 1)
34    return FAIL;
35  return OK;
36}
37
38cc1_plugin::status
39cc1_plugin::connection::send (const void *buf, int len)
40{
41  if (write (m_fd, buf, len) != len)
42    return FAIL;
43  return OK;
44}
45
46cc1_plugin::status
47cc1_plugin::connection::require (char c)
48{
49  char result;
50
51  if (read (m_fd, &result, 1) != 1
52      || result != c)
53    return FAIL;
54
55  return OK;
56}
57
58cc1_plugin::status
59cc1_plugin::connection::get (void *buf, int len)
60{
61  if (read (m_fd, buf, len) != len)
62    return FAIL;
63  return OK;
64}
65
66cc1_plugin::status
67cc1_plugin::connection::do_wait (bool want_result)
68{
69  while (true)
70    {
71      char result;
72      fd_set read_set;
73
74      FD_ZERO (&read_set);
75      FD_SET (m_fd, &read_set);
76      if (m_aux_fd != -1)
77	FD_SET (m_aux_fd, &read_set);
78
79      int nfds = select (FD_SETSIZE, &read_set, NULL, NULL, NULL);
80      if (nfds == -1)
81	{
82	  if (errno == EINTR)
83	    continue;
84	  return FAIL;
85	}
86
87      // We have to check the stderr fd first, to avoid a possible
88      // blocking scenario when do_wait is called reentrantly.  In
89      // such a call, if we handle the primary fd first, then we may
90      // re-enter this function, read from gcc's stderr, causing the
91      // outer invocation of this function to block when trying to
92      // read.
93      if (m_aux_fd != -1 && FD_ISSET (m_aux_fd, &read_set))
94	{
95	  char buf[1024];
96	  int n = read (m_aux_fd, buf, sizeof (buf) - 1);
97	  if (n < 0)
98	    return FAIL;
99	  if (n > 0)
100	    {
101	      buf[n] = '\0';
102	      print (buf);
103	    }
104	}
105
106      if (FD_ISSET (m_fd, &read_set))
107	{
108	  int n = read (m_fd, &result, 1);
109	  if (n == 0)
110	    return want_result ? FAIL : OK;
111	  if (n != 1)
112	    return FAIL;
113
114	  switch (result)
115	    {
116	    case 'R':
117	      // The reply is ready; the caller will unmarshall it.
118	      return want_result ? OK : FAIL;
119
120	    case 'Q':
121	      // While waiting for a reply, the other side made a method
122	      // call.
123	      {
124		// Use an argument_wrapper here to simplify management
125		// of the string's lifetime.
126		argument_wrapper<char *> method_name;
127
128		if (!method_name.unmarshall (this))
129		  return FAIL;
130
131		callback_ftype *callback
132		  = m_callbacks.find_callback (method_name.get ());
133		// The call to CALLBACK is where we may end up in a
134		// reentrant call.
135		if (callback == NULL || !callback (this))
136		  return FAIL;
137	      }
138	      break;
139
140	    default:
141	      return FAIL;
142	    }
143	}
144    }
145}
146