mmm, strange,
When i check in the piaware.logs since 10 march, the problem occours after upgrading to 3.7.0.1,
Nothing changed in the hardware-setup…
It’s not the dongle stuck, the error we both had stops faup from operating until it automatically restarts.
You posted the errors independently, but you can see no messages being received by piaware after the other error.
I’ve put in something to catch the split error:
198 if {[catch {array set row [split $line "\t"]} catchResult] == 1} {
199 logger "got '$catchResult' reading from $prettyName"
200 logger "Uneven number of elements: '$line'"
201 faup_restart
202 return
203 }
204 array set row [split $line "\t"]
This is what it caught:
Apr 07 21:42:42 x230 piaware[17780]: got 'list must have an even number of elements' reading from faup1090
Apr 07 21:42:42 x230 piaware[17780]: Uneven number of elements: '_v 4E clock 1554666161 hexid 48AD81 addrtype adsb_icao adsb_version 2 category A3 nac_p 10 0 A nac_v 2 0 A sil 3 0 A sil_type perhour 0 A nic_baro 1 0 A airGround A+ 0 A squawk 4716 2 A ident {LOT2EL } 17 A alt 37000 0 A position {50.14105 9.35522 8 186} 0 A alt_gnss 36700 0 A vrate 128 0 A vrate_geom 64 1 U speed 424.7 0 A speed_ias 247 1 U speed_tas 434 1 U mach 0.764 1 U track 108.0 0 A track_rate 0.03 1 U roll 0.2 1 U heading_magnetic 107.8 1 U nav_alt_mcp 37024 0 A nav_alt_fms 37008 1 U nav_alt_src aircraft 1 U nav_modes {autopilot althold tcas} 0 A nav_qnh 1013.6 0 A emergency none 2 A
Apr 07 21:42:42 x230 piaware[17780]: _v 4E clock 1554666150 hexid 44029F airGround A+ 0 S squawk 5244 0 U alt 37000 4 U'
--
Apr 08 04:11:02 x230 piaware[9040]: got 'list must have an even number of elements' reading from faup1090
Apr 08 04:11:02 x230 piaware[9040]: Uneven number of elements: '_v 4E clock 1554689461 hexid AE1467 addrtype adsb_icao adsb_version 2 category A5 nac_p 9 0 A nac_v 2 0 A sil 3 0 A sil_type perhour 0 A nic_baro 1 0 A airGround A+ 0 A squawk 6437 0 A ident {RCH122 } 9 A alt 29675 0 A position {49.72563 9.82301 9 75} 0 A alt_gnss 29575 0 A vrate 576 0 U vrate_geom 704 0 A speed 420.9 0 A speed_ias 279 0 U speed_tas 430 2 U mach 0.736 0 U track 86.2 0 A track_rate 0.00 2 U roll -0.2 2 U heading_magnetic 86.5 0 U nav_alt_mcp 31008 2 A nav_alt_fms 30992 1 U nav_alt_src fms 1 U nav_heading 87.2 2 A nav_modes {vnav tcas} 2 A nav_qnh 1013.6 2 A emergency none 0 A
Apr 08 04:11:02 x230 piaware[9040]: _v 4E clock 1554689462 hexid A3E89A nac_p 9 0 A airGround A+ 0 A squawk 3234 3 A ident {CMB595 } 4 A alt 40000 0 A position {49.70136 10.07001 8 186} 0 A alt_gnss 39500 0 A vrate 0 0 A vrate_geom 32 0 U speed 461.9 0 A speed_ias 240 0 U speed_tas 460 0 U mach 0.792 0 U track 293.1 0 A track_rate 0.00 0 U roll -0.4 0 U heading_magnetic 290.9 0 U nav_alt_mcp 40000 0 A nav_alt_fms 40000 0 U nav_heading 290.4 0 A nav_qnh 1013.6 0 A emergency none 3 A'
So it seems one of the lines is missing \n at the end of the line, otherwise they would not both be printed by the logger at once.
And while you are correct the following call so safe_snprintf would trigger the overflow, it doesn’t trigger your detection if exactly the last \n is replaced by \0
Because vsnprintf wrote exactly 1 character, just not the one you wanted to write.
return value == size is one of the error cases basically and this is not checked.
1909 p = safe_snprintf(p, end, "\n");
1910
1911 if (p <= end)
1912 completeWrite(&Modes.fatsv_out, p);
So it should still be if (p < end) to detect that case.
(Not that it really matters when the buffer is big enough but it’s nice only getting the overflow warning instead of faup crashing)
Edit: Nevermind, i’m not sure i understand the output after catching the error.
The '$line' should be on one line, not on two.
Maybe you can figure it out 
Nonetheless converting the 8 spaces back to 1 space, the first line of the two caught after the error is exactly 600 characters, so (p<end) is probably a correct solution to the problem.
Not sure why it is displayed by tcl on two lines though, maybe it’s making a new line because of the \0 but doesn’t use it for splitting lines when reading the input?
Hm, I think I misunderstood [v]snprintf; in the case where the output buffer is too small, I expected it to not write a \0 (i.e. you end up with an unterminated buffer) but it looks like that is not correct.
I’ll revisit this when I’m able to work on this again (it may be a few weeks)
It’s not that important, increasing the buffer should do the trick
Just wanted to get to the root cause of the split error, that error means no messages to Flightaware for an hour until piaware decides to restart everything.
Where can I increase the buffer size, in which file can i find TSV_MAX_PACKET_SIZE ?
Did you compile piaware? In that case it is located here:
piaware_builder/package-stretch/dump1090/net_io.c
#define TSV_MAX_PACKET_SIZE 600
(line 1881, making it 700 should be plenty)
And i was talking about the buffer which is defined by the max packet size, so changing that number is sufficient. Haven’t tested increasing it though, don’t know if it could cause other issues but at first glance i don’t think so.
If you are using the sd-card image you’ll just have to wait for a fix or switch back to 3.6.3 for now.
2 Likes
Lets see and try
Up and running …now we wait 
Mmmm
faup1090(16681): fatsv: output too large (max 600, overran by 1)
cough you need to build piaware again and reinstall it cough
Oh a little caveat, you must not run sensible-build.sh again, it will overwrite your changes to the source files in the folder package-stretch
My mistake , build the wrong version 
Just as a more tidy writeup of my understanding of the problem and a good place for you to check back in a couple of weeks, a pull request on github:
Overflow fix by wiedehopf · Pull Request #40 · flightaware/dump1090 · GitHub
2 Likes
Build Piaware again with
#define TSV_MAX_PACKET_SIZE 700
Running fine
1 Like
So for those of us who don’t want to get into a science experiment, wait until 3.7.0.2 or 3.7.1?
The testing image is mostly for UAT support.
If you don’t want UAT support there is almost no difference to 3.6.3.
Once it is released your installation should upgrade automatically if you have that enabled.
1 Like
Don’t know what UAT is… 
I’m good then!
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ok, stupid question time because it’s been a long time since Ive done this (or thought about doing it).
I want to edit config.js to change the range ring distances.
I’ve seen lots of posts how to do it, but they all assume you know how to get a prompt and I can’t remember or figure out how to get to the command prompt in the Raspberry Pi to make those changes.
I know the answer probably is keyboard and mouse and HDMI to a monitor, but there has to be a better way for me.
I have windows 10, the Piaware is on my same home router. When I go to my router and look at the devices, I type in the IP of the Piaware and it takes me to a status screen, not something that might yield a command prompt for me to change directory and then edit the config.js file.
I thought the last time I did something to the configuration settings, I did it from my account’s “MY ADS-B” where there would be a box to enter commands but I just looked and those seem to be fixed commands without something for me to enter a custom command like the change directory command and then eventually the editor command to edit config.js.
I am glad this was dummy proof that I could install piaware on a microsd card and put it in a Pi (I’m an arduino user, not a raspberry pi user) but it leads to problems trying to figure out how to easily get a Pi command line.
Thanks for any help.
You will be looking to use SSH on your pc to bring up a terminal session on the pi.
You would normally use a program called Putty.
You will need to have enabled SSH on the pi by creating an empty file called ssh. If you did it initially it will still be there otherwise pop the sdcard back into the pc.
S.
I’m familiar with Putty - I have to use it to SSH into my ISP account that runs on some flavor of linux when I have files to update on my webpage.
I doubt I have the blank SSH file on my Pi as I did the dummy method of taking the equivalent of an ISO file distribution and used some software to burn it to the microSD card in the right format and directory structure that was needed for Piaware on the Pi.
Since you are telling me that I can take the microSD card and plug it into my PC microSD card reader, it is in a format that I’m able to look at with windows explorer and add the SSH file or edit the config.js file directly?
Thanks.
For Beginners - How-to SSH to RPi - Setup Putty in Windows
Once you are on the prompt you can change directory with:
cd /usr/share/dump1090-fa/html
to edit, you can use nano for example, as you need root permissions to edit the file you need to use sudo as well:
sudo nano config.js
(sudo makes you root for the following command only)
Ctrl-x to exit, it will ask you wether to save, say y for yes and press enter when prompted for the path (stays the same).