From a3463829567defda8aefa8425e79ff4d270617ba Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 11 May 2023 09:30:46 +0200
Subject: Use fake lock for fake machine locking

---
 bbot/agent/agent.cxx | 46 ++++++++++++++++++++++++++--------------------
 1 file changed, 26 insertions(+), 20 deletions(-)

(limited to 'bbot')

diff --git a/bbot/agent/agent.cxx b/bbot/agent/agent.cxx
index 24e3f81..8f54346 100644
--- a/bbot/agent/agent.cxx
+++ b/bbot/agent/agent.cxx
@@ -505,10 +505,13 @@ public:
     {
       fl_ = false; // We have tried.
 
-      try_rmfile (fp_, ignore_errors);
+      if (fd_ != nullfd)
+      {
+        try_rmfile (fp_, ignore_errors);
 
-      if (flock (fd_.get (), LOCK_UN) != 0 && !ignore_errors)
-        throw_generic_error (errno);
+        if (flock (fd_.get (), LOCK_UN) != 0 && !ignore_errors)
+          throw_generic_error (errno);
+      }
     }
   }
 
@@ -522,23 +525,26 @@ public:
   {
     assert (tl.locked () && fl_);
 
-    pid_t pid (getpid ());
+    if (fd_ != nullfd)
+    {
+      pid_t pid (getpid ());
 
-    string l (to_string (pid));
+      string l (to_string (pid));
 
-    if (prio)
-    {
-      l += ' ';
-      l += to_string (*prio);
-    }
+      if (prio)
+      {
+        l += ' ';
+        l += to_string (*prio);
+      }
 
-    auto n (fdwrite (fd_.get (), l.c_str (), l.size ()));
+      auto n (fdwrite (fd_.get (), l.c_str (), l.size ()));
 
-    if (n == -1)
-      throw_generic_ios_failure (errno);
+      if (n == -1)
+        throw_generic_ios_failure (errno);
 
-    if (static_cast<size_t> (n) != l.size ())
-      throw_generic_ios_failure (EFBIG);
+      if (static_cast<size_t> (n) != l.size ())
+        throw_generic_ios_failure (EFBIG);
+    }
   }
 
   ~machine_lock ()
@@ -555,6 +561,8 @@ public:
   // Implementation details.
   //
 public:
+  // If fd is nullfd, treat it as a fake lock (used for fake machines).
+  //
   machine_lock (path&& fp, auto_fd&& fd)
       : fp_ (move (fp)), fd_ (move (fd)), fl_ (true) {}
 
@@ -719,7 +727,7 @@ try
       r.push_back (
         bootstrapped_machine {
           dir_path (ops.machines ()) /= mh.name, // For diagnostics.
-          machine_lock (),
+          machine_lock (path (), nullfd),        // Fake lock.
           bootstrapped_machine_manifest {
             machine_manifest {
               move (mh.id),
@@ -1771,7 +1779,7 @@ try
     {
       // @@ For now skip machines locked by other processes.
       //
-      if (ops.fake_machine_specified () || m.lock.locked ())
+      if (m.lock.locked ())
         tq.machines.emplace_back (m.manifest.machine.id,
                                   m.manifest.machine.name,
                                   m.manifest.machine.summary);
@@ -1942,9 +1950,7 @@ try
         {
           if (mh.name == m.manifest.machine.name)
           {
-            if (!ops.fake_machine_specified ())
-              m.lock.write (tl, 1234 /* prio */);
-
+            m.lock.write (tl, 1234 /* prio */);
             pm = &m;
           }
           else
-- 
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