1/* Connect implementation
2 Copyright (C) 2014-2025 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 (fd: m_fd, buf: &c, n: 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 (fd: m_fd, buf: buf, n: 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 (fd: m_fd, buf: &result, nbytes: 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 (fd: m_fd, buf: buf, nbytes: 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, readfds: &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 (fd: m_aux_fd, buf: buf, nbytes: 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 (fd: m_fd, buf: &result, nbytes: 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 (conn: this))
129 return FAIL;
130
131 callback_ftype *callback
132 = m_callbacks.find_callback (name: 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

source code of libcc1/connection.cc