1GPSFAKE(1) GPSD Documentation GPSFAKE(1)
2
6 gpsfake - test harness for gpsd, simulating a GPS
7
9 gpsfake [-1] [-h] [-b] [-c interval] [-i] [-D debuglevel] [-l]
10 [-m monitor] [-g] [-G] [-n] [-o options] [-p] [-P port] [-q]
11 [-r initcmd] [-s speed] [-S] [-u] [-t] [-T] [-v] [-W timeout]
12 [logfile...]
13
15 gpsfake is a test harness for gpsd and its clients. It opens a pty
16 (pseudo-TTY), launches a gpsd instance that thinks the slave side of
17 the pty is its GPS device, and repeatedly feeds the contents of one or
18 more test logfiles through the master side to the GPS. If there are
19 multiple logfiles, sentences from them are interleaved in the order the
20 files are specified.
21 gpsfake does not require root privileges, and can be run concurrently
23 with a production gpsd instance without causing problems.
24 The logfiles may contain packets in any supported format, including in
26 particular NMEA, SiRF, TSIP, or Zodiac. Leading lines beginning with #
27 will be treated as comments and ignored, except in the following
28 special cases:
29 · a comment of the form #Date: yyyy-mm-dd (ISO8601 date format) may
31 be used to set the initial date for the log.
32 · a comment of the form #Serial: [0-9]* [78][NOE][12] may be used to
34 set serial parameters for the log - baud rate, word length, stop
35 bits.
36 · a comment of the form #Transport: UDP may be used to fake a UDP
38 source rather than the normal pty.
39 The gpsd instance is run in foreground. The thread sending fake GPS
41 data to the daemon is run in background.
42
44 With the -1 option, the logfile is interpreted once only rather than
45 repeatedly. This option is intended to facilitate regression testing.
46 The -b enables a twirling-baton progress indicator on standard error.
48 At termination, it reports elapsed time.
49 The -c sets the delay between sentences in seconds. Fractional values
51 of seconds are legal. The default is zero (no delay).
52 The -l makes the program dump a line or packet number just before each
54 sentence is fed to the daemon. If the sentence is textual (e.g. NMEA),
55 the text is dumped as well. If not, the packet will be dumped in
56 hexadecimal (except for RTCM packets, which aren't dumped at all). This
57 option is useful for checking that gpsfake is getting packet boundaries
58 right.
59 The -i is for single-stepping through logfiles. It dumps the line or
61 packet number (and the sentence if the protocol is textual) followed by
62 "? ". Only when the user keys Enter is the line actually fed to gpsd.
63 The -m specifies a monitor program inside which the daemon should be
65 run. This option is intended to be used with valgrind(1), gdb(1) and
66 similar programs.
67 The -g and -G options use the monitor facility to run the gpsd instance
69 within gpsfake under control of gdb or lldb, respectively. They also
70 disable the timeout on daemon inactivity, to allow for breakpointing.
71 If necessary, the timeout can be reenabled by a subsequent -W.
72 The -o specifies options to pass to the daemon. The -n option passes -n
74 to start the daemon reading the GPS without waiting for a client
75 (equivalent to -o "-n"). The -D passes a -D option to the daemon: thus
76 -D 4 is shorthand for -o "-D 4".
77 The -p ("pipe") option sets watcher mode and dumps the NMEA and GPSD
79 notifications generated by the log to standard output. This is useful
80 for regression-testing.
81 The -P ("port") option sets the daemon's listening port.
83 The -q tells gpsfake to suppress normal progress output and thus act in
85 a quiet manner.
86 The -r specifies an initialization command to use in pipe mode. The
88 default is ?WATCH={"enable":true,"json":true}.
89 The -s sets the baud rate for the slave tty. The default is 4800.
91 The option -S tells gpsfake to insert realistic delays in the test
93 input rather than trying to stuff it through the daemon as fast as
94 possible. This will make the test(s) run much slower, but avoids flaky
95 failures due to machine lode and possible race conditions in the pty
96 layer.
97 The -t forces the test framework to use TCP rather than pty devices.
99 Besides being a test of TCP source handling, this may be useful for
100 testing from within chroot jails where access to pty devices is locked
101 out.
102 The -T makes gpsfake print some system information and then exits.
104 The -u forces the test framework to use UDP rather than pty devices.
106 Besides being a test of UDP source handling, this may be useful for
107 testing from within chroot jails where access to pty devices is locked
108 out.
109 The -v enables verbose progress reports to stderr. It is mainly useful
111 for debugging gpsfake itself.
112 The -W ("wait") option sets the timeout on daemon inactivity, in
114 seconds. The default timeout is 60 seconds, and a value of 0 suppresses
115 the timeout altogether. Note that the actual timeout is longer due to
116 internal delays, typically by about 20 seconds.
117 The -x dumps packets as gpsfake gathers them. It is mainly useful for
119 debugging gpsfake itself.
120 The -h makes gpsfake print a usage message and exit.
122 The argument must be the name of a file containing the data to be
124 cycled at the device. gpsfake will print a notification each time it
125 cycles.
126 Normally, gpsfake creates a pty for each logfile and passes the slave
128 side of the device to the daemon. If the header comment in the logfile
129 contains the string "UDP", packets are instead shipped via UDP port
130 5000 to the address 192.168.0.1.255. You can monitor them with this:
131 tcpdump -s0 -n -A -i lo udp and port 5000.
132
134 Certain magic comments in test load headers can change the conditions
135 of the test. These are:
136 Serial:
138 May contain a serial-port setting such as 4800 7N2 - baud rate
139 followed by 7 or 8 for byte length, N or O or E for parity and 1 or
140 2 for stop bits. The test is run with those settings on the slave
141 port that the daemon sees.
142 Transport:
144 Values 'TCP' and 'UDP' force the use of TCP and UDP feeds
145 respectively (the default is a pty).
146 Delay-Cookie:
148 Must be followed by two whitespace-separated fields, a delimiter
149 character and a numeric delay in seconds. Instead of being broken
150 up by packet boundaries, the test load is split on the delimiters.
151 The delay is performed after each feed. Can be useful for imposing
152 write boundaries in the middle of packets.
153
155 gpsfake is a trivial wrapper around a Python module, also named
156 gpsfake, that can be used to fully script sessions involving a gpsd
157 instance, any number of client sessions, and any number of fake GPSes
158 feeding the daemon instance with data from specified sentence logs.
159 Source and embedded documentation for this module is shipped with the
161 gpsd development tools. You can use it to torture-test either gpsd
162 itself or any gpsd-aware client application.
163 Logfiles for the use with gpsfake can be retrieved using gpspipe,
165 gpscat, or gpsmon from the gpsd distribution, or any other application
166 which is able to create a compatible output.
167 If gpsfake exits with "Cannot execute gpsd: executable not found." the
169 environment variable GPSD_HOME can be set to the path where gpsd can be
170 found. (instead of adding that folder to the PATH environment variable
171
173 gpsd(8), gps(1), libgps(3), libgpsmm(3), gpsctl(1), gpspipe(1),
174 gpsprof(1) gpsmon(1).
175
177 Eric S. Raymond <esr@thyrsus.com>.
178The GPSD Project 12 Feb 2005 GPSFAKE(1)