Pass server arguments over socket

[rom1v]

I tried to improve readability/robustness of configuration passed from the client ot the server: 870ced0 (branch name_params)

But on Windows, it failed:

ERROR: Command too long (255 chars)
ERROR: Failed to execute: [adb], [shell], [CLASSPATH=/data/local/tmp/scrcpy-server.jar], [app_process], [/], [com.genymobile.scrcpy.Server], [1.13], [max_size=0], [bit_rate=8000000], [max_fps=0], [lock_video_orientation=-1], [tunnel_forward=false], [crop=], [send_frame_meta=true], [control=true], [display_id=0], [show_touches=false], [stay_awake=false] 

I think many of these key=value pairs should be passed over the socket (not tunnel_forward because the socket creation depends on it).

Or maybe you have a better idea?

[berniegp]

I got redirected here by this Google search: "scrcpy Command too long (255 chars)"

My problem is that I set this

ADB="C:\Program Files\Unity\Hub\Editor\2020.2.1f1\Editor\Data\PlaybackEngines\AndroidPlayer\SDK\platform-tools\adb.exe"

and got this:

C:\Builds>scrcpy --max-size 720 --bit-rate 1M --max-fps 30 --show-touches --always-on-top
INFO: scrcpy 1.17 <https://github.com/Genymobile/scrcpy>
C:\ProgramData\chocolatey\lib\scrcpy\tools\scrcpy-server: 1 file pushed. 2.3 MB/s (34930 bytes in 0.014s)
ERROR: Command too long (255 chars)
ERROR: Failed to execute: [C:\Program Files\Unity\Hub\Editor\2020.2.1f1\Editor\Data\PlaybackEngines\AndroidPlayer\SDK\platform-tools\adb.exe], [shell], [CLASSPATH=/data/local/tmp/scrcpy-server.jar], [app_process], [/], [com.genymobile.scrcpy.Server], [1.17], [info], [720], [1000000], [30], [-1], [false], [-], [true], [true], [0], [true], [false], [-], [-]

I get this error even if I enable long path support in Windows 10 via

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\LongPathsEnabled

I was able to get around this problem with subst:

subst x: "C:\Program Files\Unity\Hub\Editor\2020.2.1f1\Editor\Data\PlaybackEngines\AndroidPlayer\SDK\platform-tools"
ADB="x:\adb.exe"

# to unmap x: drive
subst x: /D

So it looks like something in the scrcpy pipeline is limiting the path length.

[rom1v]

It's only limited on Windows releases by mingw. If you know a solution to extand this limit on mingw, please help.

[Biswa96]

Though it will be a misery to deal with, did you try using Unicode Win32 functions i.e. CreateProcessW? Also try with prepending \\?\ before the command line, e.g. L"\\\\?\\MyFiles\\adb.exe". CreateFileW has that kind of trickery.

[berniegp]

I don't know the actual solution unfortunately. I mostly wanted to post the workaround as reference.

However, I did a bit of digging based on how Git for Windows (it uses mingw) handles long paths (the core.longpaths option) and found interesting sources that match what @Biswa96 mentions:

handle_long_path() in
https://github.com/git-for-windows/git/blob/main/compat/mingw.h
https://github.com/git-for-windows/git/blob/main/compat/mingw.c

A blog that discusses this:
https://www.brycevandyk.com/of-too-long-file-names-in-windows-and-git/

Hopefully this can help!

[rom1v]

Thank you for the links.

Note that here the problem is that the command (including the arguments) is too long, not the path of the executable.

[Biswa96]

Yes, I also mean the command line, the second argument in CreateProcessW, the lpCommandLine. Off-topic, see my little experiment here as an example.

[rom1v]

Oh, but I'm stupid, the error Command too long comes from scrcpy:

scrcpy/app/src/sys/win/process.c

Line 17 in a1f2094

LOGE("Command too long (%" PRIsizet " chars)", len - 1);

scrcpy/app/src/sys/win/process.c

Line 30 in a1f2094

char cmd[256];

🤦

[rom1v]

Not relevant anymore. See a9d9cbf.

Also refs:

• 2eb881c
• 04e5537
• 7b29f5f