1 /* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ |
|
2 |
|
3 /* |
|
4 * Copyright (c) 2010 The Boeing Company |
|
5 * |
|
6 * This program is free software; you can redistribute it and/or modify |
|
7 * it under the terms of the GNU General Public License version 2 as |
|
8 * published by the Free Software Foundation; |
|
9 * |
|
10 * This program is distributed in the hope that it will be useful, |
|
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of |
|
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
|
13 * GNU General Public License for more details. |
|
14 * |
|
15 * You should have received a copy of the GNU General Public License |
|
16 * along with this program; if not, write to the Free Software |
|
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
|
18 * |
|
19 * Author: Tom Goff <thomas.goff@boeing.com> |
|
20 */ |
|
21 |
|
22 #include <errno.h> |
|
23 #include <string.h> |
|
24 #include <unistd.h> |
|
25 #include <fcntl.h> |
|
26 |
|
27 #include "ns3/log.h" |
|
28 #include "ns3/fatal-error.h" |
|
29 #include "ns3/simple-ref-count.h" |
|
30 #include "ns3/system-thread.h" |
|
31 #include "ns3/simulator.h" |
|
32 |
|
33 #include "unix-fd-reader.h" |
|
34 |
|
35 NS_LOG_COMPONENT_DEFINE ("FdReader"); |
|
36 |
|
37 namespace ns3 { |
|
38 |
|
39 FdReader::FdReader () |
|
40 : m_fd (-1), m_readCallback (0), m_readThread (0), m_stop (false), |
|
41 m_destroyEvent () |
|
42 { |
|
43 m_evpipe[0] = -1; |
|
44 m_evpipe[1] = -1; |
|
45 } |
|
46 |
|
47 FdReader::~FdReader () |
|
48 { |
|
49 Stop (); |
|
50 } |
|
51 |
|
52 void FdReader::Start (int fd, Callback<void, uint8_t *, ssize_t> readCallback) |
|
53 { |
|
54 int tmp; |
|
55 |
|
56 NS_ASSERT_MSG (m_readThread == 0, "read thread already exists"); |
|
57 |
|
58 // create a pipe for inter-thread event notification |
|
59 tmp = pipe (m_evpipe); |
|
60 if (tmp == -1) |
|
61 { |
|
62 NS_FATAL_ERROR ("pipe() failed: " << strerror (errno)); |
|
63 } |
|
64 |
|
65 // make the read end non-blocking |
|
66 tmp = fcntl(m_evpipe[0], F_GETFL); |
|
67 if (tmp == -1) |
|
68 { |
|
69 NS_FATAL_ERROR ("fcntl() failed: " << strerror (errno)); |
|
70 } |
|
71 if (fcntl(m_evpipe[0], F_SETFL, tmp | O_NONBLOCK) == -1) |
|
72 { |
|
73 NS_FATAL_ERROR ("fcntl() failed: " << strerror (errno)); |
|
74 } |
|
75 |
|
76 m_fd = fd; |
|
77 m_readCallback = readCallback; |
|
78 |
|
79 // |
|
80 // We're going to spin up a thread soon, so we need to make sure we have |
|
81 // a way to tear down that thread when the simulation stops. Do this by |
|
82 // scheduling a "destroy time" method to make sure the thread exits before |
|
83 // proceeding. |
|
84 // |
|
85 if (! m_destroyEvent.IsRunning ()) |
|
86 { |
|
87 // hold a reference to ensure that this object is not |
|
88 // deallocated before the destroy-time event fires |
|
89 this->Ref (); |
|
90 m_destroyEvent = |
|
91 Simulator::ScheduleDestroy (&FdReader::DestroyEvent, this); |
|
92 } |
|
93 |
|
94 // |
|
95 // Now spin up a thread to read from the fd |
|
96 // |
|
97 NS_LOG_LOGIC ("Spinning up read thread"); |
|
98 |
|
99 m_readThread = Create<SystemThread> (MakeCallback (&FdReader::Run, this)); |
|
100 m_readThread->Start (); |
|
101 } |
|
102 |
|
103 void FdReader::DestroyEvent (void) |
|
104 { |
|
105 Stop (); |
|
106 this->Unref (); |
|
107 } |
|
108 |
|
109 void FdReader::Stop (void) |
|
110 { |
|
111 m_stop = true; |
|
112 |
|
113 // signal the read thread and close the write end of the event pipe |
|
114 if (m_evpipe[1] != -1) |
|
115 { |
|
116 char zero = 0; |
|
117 ssize_t len = write (m_evpipe[1], &zero, sizeof (zero)); |
|
118 if (len != sizeof (zero)) |
|
119 NS_LOG_WARN ("incomplete write(): " << strerror (errno)); |
|
120 close (m_evpipe[1]); |
|
121 m_evpipe[1] = -1; |
|
122 } |
|
123 |
|
124 // join the read thread |
|
125 if (m_readThread != 0) |
|
126 { |
|
127 m_readThread->Join (); |
|
128 m_readThread = 0; |
|
129 } |
|
130 |
|
131 // close the read end of the event pipe |
|
132 if (m_evpipe[0] != -1) |
|
133 { |
|
134 close (m_evpipe[0]); |
|
135 m_evpipe[0] = -1; |
|
136 } |
|
137 |
|
138 // reset everything else |
|
139 m_fd = -1; |
|
140 m_readCallback.Nullify (); |
|
141 m_stop = false; |
|
142 } |
|
143 |
|
144 // This runs in a separate thread |
|
145 void FdReader::Run (void) |
|
146 { |
|
147 int nfds; |
|
148 fd_set rfds; |
|
149 |
|
150 nfds = (m_fd > m_evpipe[0] ? m_fd : m_evpipe[0]) + 1; |
|
151 |
|
152 FD_ZERO (&rfds); |
|
153 FD_SET (m_fd, &rfds); |
|
154 FD_SET (m_evpipe[0], &rfds); |
|
155 |
|
156 for (;;) |
|
157 { |
|
158 int r; |
|
159 fd_set readfds = rfds; |
|
160 |
|
161 r = select (nfds, &readfds, NULL, NULL, NULL); |
|
162 if (r == -1 && errno != EINTR) |
|
163 { |
|
164 NS_FATAL_ERROR ("select() failed: " << strerror (errno)); |
|
165 } |
|
166 |
|
167 if (FD_ISSET (m_evpipe[0], &readfds)) |
|
168 { |
|
169 // drain the event pipe |
|
170 ssize_t len; |
|
171 for (;;) |
|
172 { |
|
173 char buf[1024]; |
|
174 len = read (m_evpipe[0], buf, sizeof (buf)); |
|
175 if (len == 0) |
|
176 { |
|
177 NS_FATAL_ERROR ("event pipe closed"); |
|
178 } |
|
179 if (len < 0) |
|
180 { |
|
181 break; |
|
182 } |
|
183 } |
|
184 |
|
185 if (len < 0 && errno != EAGAIN && errno != EWOULDBLOCK) |
|
186 { |
|
187 NS_LOG_WARN ("read() failed: " << strerror (errno)); |
|
188 break; |
|
189 } |
|
190 } |
|
191 |
|
192 if (m_stop) |
|
193 { |
|
194 // this thread is done |
|
195 break; |
|
196 } |
|
197 |
|
198 if (FD_ISSET (m_fd, &readfds)) |
|
199 { |
|
200 struct FdReader::Data data = DoRead (); |
|
201 // reading stops when m_len is zero |
|
202 if (data.m_len == 0) |
|
203 { |
|
204 break; |
|
205 } |
|
206 // the callback is only called when m_len is positive (data |
|
207 // is ignored if m_len is negative) |
|
208 else if (data.m_len > 0) |
|
209 { |
|
210 m_readCallback (data.m_buf, data.m_len); |
|
211 } |
|
212 } |
|
213 } |
|
214 } |
|
215 |
|
216 } // namespace ns3 |
|