Client Development

[jcoffland]

Hello. This is a discussion thread for development of the client and web front end and pre-alpha release discussions.

The latest bleeding edge builds can now be download from https://master.foldingathome.org/builds/fah-client/

@kbernhagen, @Hou5e, @marcosfrm

[jcoffland]

Has anyone tested accounts and remotes with v8.3.x on windows? And on which browsers?

[Hou5e]

I compiled from source on (4) Linux Mint 21.1 (Ubuntu 22.04) PCs today and did update installs on top of existing FAH v8.2.4. I've only tested with Firefox, so far. I could log-out and log into my account. I can't access any of my PCs remotely but they show up in the list (since it was introduced in FAH v8.2. My account: https://stats.foldingathome.org/donor/id/245474 might need to be fixed or something). I also get this error for each startup: #178

[jcoffland]

Do you get the #178 error with ARM Linux or something else?

[marcosfrm]

systemd has tons of hardening options. Evaluate add a few to our Linux service file for paranoia:

https://docs.arbitrary.ch/security/systemd.html

Some options are supported since ages (PrivateTmp= and NoNewPrivileges= for example), others require recent versions.

[jcoffland]

This would be a good thing to open an issue for.

[marcosfrm]

ca-certificates dependency in DEB package is indeed necessary. fah-client will static link libssl.a and libcrypto.a provided by libssl-dev and Debian only pulls it in weakly (Suggests) via openssl package (not via libssl1.1/libssl3). Minimal installs thus can lack ca-certificates.

On Fedora/RHEL, openssl-libs requires ca-certificates. Hence linking system OpenSSL guarantees ca-certificates is present. See #153 (comment) for a viable approach (static libraries are not provided anymore there).

[marcosfrm]

When possible I think fah-client should link system core libraries. zlib and bzip2 are good candidates, as their ABI is not going break soon (or ever). Installing zlib1g-dev and libbz2-dev on Debian 12 results in:

Depends: ca-certificates, libbz2-1.0, libc6 (>= 2.36), libsystemd0 (>= 222), zlib1g (>= 1:1.1.4)

And zlib-devel and bzip2-devel on CentOS Stream 8:

$ rpm -q --requires fah-client
...
libbz2.so.1()(64bit)
...
libz.so.1()(64bit)
...

Symbol versioning was added in zlib 1.2.0 (2006) and DEB/RPM will make use of it. libbz2 does not have it, but its API is frozen for a long time (two decades?) anyway.

Requires CauldronDevelopmentLLC/cbang@5e4dfec.

[marcosfrm]

Investigate whether setting core's scheduling policy to SCHED_BATCH on Linux (keeping nice level at 19) is beneficial.

https://man7.org/linux/man-pages/man7/sched.7.html
https://man7.org/linux/man-pages/man2/sched_setscheduler.2.html

SCHED_BATCH is Linux-specific. Requires _GNU_SOURCE, which is always defined by g++ and clang++ on Linux I think.

Test patch for cbang:

diff --git a/src/cbang/os/SystemUtilities.cpp b/src/cbang/os/SystemUtilities.cpp
index e66ca262..79e09636 100644
--- a/src/cbang/os/SystemUtilities.cpp
+++ b/src/cbang/os/SystemUtilities.cpp
@@ -81,6 +81,10 @@
 #include <mach-o/dyld.h>
 #endif // __APPLE__
 
+#ifdef __linux__
+#include <sched.h>
+#endif // __linux__
+
 #include <sstream>
 #include <fstream>
 #include <iomanip>
@@ -859,6 +863,13 @@ namespace cb {
 
       if (SysError::get())
         THROW("Failed to set process priority: " << SysError());
+
+#if defined(__linux__) && defined(SCHED_BATCH)
+      struct sched_param sp = {0};
+
+      if (priority == ProcessPriority::PRIORITY_IDLE)
+        sched_setscheduler((pid_t)pid, SCHED_BATCH, &sp);
+#endif
 #endif
     }