libstore: asyncify LocalStore::findPlatformRoots

Change-Id: I173fae8aa17cb757b9c2aceadb4d68259a236b32

lix/libstore/gc.cc

@@ -359,8 +359,8 @@ try {
     co_return result::current_exception();
 }
 
-void LocalStore::findPlatformRoots(UncheckedRoots & unchecked)
-{
+kj::Promise<Result<void>> LocalStore::findPlatformRoots(UncheckedRoots & unchecked)
+try {
     // N.B. This is (read: undertested!) fallback code only used for
     // non-Darwin, non-Linux platforms. Both major platforms have
     // platform-specific code in lix/libstore/platform/
@@ -376,13 +376,17 @@ void LocalStore::findPlatformRoots(UncheckedRoots & unchecked)
     } catch (ExecError & e) {
         /* lsof not installed, lsof failed */
     }
+
+    co_return result::success();
+} catch (...) {
+    co_return result::current_exception();
 }
 
 kj::Promise<Result<void>> LocalStore::findRuntimeRoots(Roots & roots, bool censor)
 try {
     UncheckedRoots unchecked;
 
-    findPlatformRoots(unchecked);
+    TRY_AWAIT(findPlatformRoots(unchecked));
 
     for (auto & [target, links] : unchecked) {
         if (!isInStore(target)) continue;

lix/libstore/local-store.hh

@@ -393,7 +393,7 @@ private:
      * Find possible garbage collector roots in a platform-specific manner,
      * e.g. by looking in `/proc` or using `lsof`
      */
-    virtual void findPlatformRoots(UncheckedRoots & unchecked);
+    virtual kj::Promise<Result<void>> findPlatformRoots(UncheckedRoots & unchecked);
 
     kj::Promise<Result<void>> findRuntimeRoots(Roots & roots, bool censor);
 

lix/libstore/platform/darwin.cc

@@ -1,4 +1,5 @@
 #include "lix/libstore/gc-store.hh"
+#include "lix/libutil/result.hh"
 #include "lix/libutil/signals.hh"
 #include "lix/libstore/platform/darwin.hh"
 #include "lix/libutil/regex.hh"
@@ -14,8 +15,8 @@
 
 namespace nix {
 
-void DarwinLocalStore::findPlatformRoots(UncheckedRoots & unchecked)
-{
+kj::Promise<Result<void>> DarwinLocalStore::findPlatformRoots(UncheckedRoots & unchecked)
+try {
     auto storePathRegex = regex::storePathRegex(config().storeDir);
 
     std::vector<int> pids;
@@ -240,6 +241,10 @@ void DarwinLocalStore::findPlatformRoots(UncheckedRoots & unchecked)
             throw;
         }
     }
+
+    co_return result::success();
+} catch (...) {
+    co_return result::current_exception();
 }
 
 void DarwinLocalDerivationGoal::execBuilder(std::string builder, Strings args, Strings envStrs)

lix/libstore/platform/darwin.hh

@@ -25,7 +25,7 @@ public:
 
 private:
 
-    void findPlatformRoots(UncheckedRoots & unchecked) override;
+    kj::Promise<Result<void>> findPlatformRoots(UncheckedRoots & unchecked) override;
 };
 
 /**

lix/libstore/platform/linux.cc

@@ -5,6 +5,7 @@
 #include "lix/libutil/finally.hh"
 #include "lix/libstore/gc-store.hh"
 #include "lix/libutil/processes.hh"
+#include "lix/libutil/result.hh"
 #include "lix/libutil/signals.hh"
 #include "lix/libstore/platform/linux.hh"
 #include "lix/libutil/regex.hh"
@@ -79,8 +80,8 @@ LinuxLocalDerivationGoal::~LinuxLocalDerivationGoal()
     }
 }
 
-void LinuxLocalStore::findPlatformRoots(UncheckedRoots & unchecked)
-{
+kj::Promise<Result<void>> LinuxLocalStore::findPlatformRoots(UncheckedRoots & unchecked)
+try {
     auto procDir = AutoCloseDir{opendir("/proc")};
     if (procDir) {
         struct dirent * ent;
@@ -154,6 +155,10 @@ void LinuxLocalStore::findPlatformRoots(UncheckedRoots & unchecked)
     readFileRoots("/proc/sys/kernel/modprobe", unchecked);
     readFileRoots("/proc/sys/kernel/fbsplash", unchecked);
     readFileRoots("/proc/sys/kernel/poweroff_cmd", unchecked);
+
+    co_return result::success();
+} catch (...) {
+    co_return result::current_exception();
 }
 
 #if HAVE_SECCOMP

lix/libstore/platform/linux.hh

@@ -23,7 +23,7 @@ public:
 
 private:
 
-    void findPlatformRoots(UncheckedRoots & unchecked) override;
+    kj::Promise<Result<void>> findPlatformRoots(UncheckedRoots & unchecked) override;
 };
 
 /**