maintenance(systemd): support the Windows Subsystem for Linux

From: Johannes Schindelin <[email protected]>

When running in the Windows Subsystem for Linux (WSL), it is usually necessary to use the Git Credential Manager for authentication when performing the background fetches.

This requires interoperability between the Windows Subsystem for Linux and the Windows host to work, which uses so-called vsocks, i.e. sockets intended for communcations between virtual machines and the host they are running on.

However, when Git is configured to run background maintenance via systemd, the address families available to those maintenance processes are restricted, and did not include AF_VSOCK. This leads to problems e.g. when a background fetch tries to access github.com:

systemd[437]: Starting Optimize Git repositories data...
git[747387]: WSL (747387) ERROR: UtilBindVsockAnyPort:285: socket failed 97 git[747381]: fatal: could not read Username for 'https://github.com': No such device or address git[747381]: error: failed to prefetch remotes
git[747381]: error: task 'prefetch' failed
systemd[437]: [email protected]: Main process exited, code=exited, status=1/FAILURE systemd[437]: [email protected]: Failed with result 'exit-code'. systemd[437]: Failed to start Optimize Git repositories data.

Address this (pun intended) by adding the AF_VSOCK address family to the allow list.

This fixes https://github.com/microsoft/git/issues/604.

---
maintenance(systemd): support the Windows Subsystem for Linux

https://github.com/microsoft/git/issues/604 reports a bug where git maintenance start does not work in the Windows Subsystem for Linux (WSL), and this patch fixes it.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1586%2Fdscho%2Fscheduled-maintenance-in-wsl-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1586/dscho/scheduled-maintenance-in-wsl-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1586

 builtin/gc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 5c4315f0d81..719cae9a88a 100644
@@ -2397,7 +2397,7 @@ static int systemd_timer_write_unit_templates(const char *exec_path)
 	       "LockPersonality=yes\n"
 	       "MemoryDenyWriteExecute=yes\n"
 	       "NoNewPrivileges=yes\n"
-	       "RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6\n"
+	       "RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6 AF_VSOCK\n"
 	       "RestrictNamespaces=yes\n"
 	       "RestrictRealtime=yes\n"
 	       "RestrictSUIDSGID=yes\n"

base-commit: 43c8a30d150ecede9709c1f2527c8fba92c65f40

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