6 files changed, 69 insertions, 16 deletions
diff --git a/src/libutil/archive.cc b/src/libutil/archive.cc
index 1be8934a2eba..bb68e82886d0 100644
--- a/src/libutil/archive.cc
+++ b/src/libutil/archive.cc
@@ -283,7 +283,7 @@ void parseDump(ParseSink & sink, Source & source)
 {
     string version;
     try {
-        version = readString(source);
+        version = readString(source, narVersionMagic1.size());
     } catch (SerialisationError & e) {
         /* This generally means the integer at the start couldn't be
            decoded.  Ignore and throw the exception below. */
diff --git a/src/libutil/pool.hh b/src/libutil/pool.hh
index 0b142b0597c7..d49067bb95dc 100644
--- a/src/libutil/pool.hh
+++ b/src/libutil/pool.hh
@@ -97,6 +97,7 @@ public:
     private:
         Pool & pool;
         std::shared_ptr<R> r;
+        bool bad = false;
 
         friend Pool;
 
@@ -112,7 +113,8 @@ public:
             if (!r) return;
             {
                 auto state_(pool.state.lock());
-                state_->idle.push_back(ref<R>(r));
+                if (!bad)
+                    state_->idle.push_back(ref<R>(r));
                 assert(state_->inUse);
                 state_->inUse--;
             }
@@ -121,6 +123,8 @@ public:
 
         R * operator -> () { return &*r; }
         R & operator * () { return *r; }
+
+        void markBad() { bad = true; }
     };
 
     Handle get()
diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index 17448f70efb6..0e75eeec2bfe 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -169,17 +169,13 @@ std::unique_ptr<Source> sinkToSource(
     {
         typedef boost::coroutines2::coroutine<std::string> coro_t;
 
+        std::function<void(Sink &)> fun;
         std::function<void()> eof;
-        coro_t::pull_type coro;
+        std::experimental::optional<coro_t::pull_type> coro;
+        bool started = false;
 
         SinkToSource(std::function<void(Sink &)> fun, std::function<void()> eof)
-            : eof(eof)
-            , coro([&](coro_t::push_type & yield) {
-                LambdaSink sink([&](const unsigned char * data, size_t len) {
-                    if (len) yield(std::string((const char *) data, len));
-                });
-                fun(sink);
-            })
+            : fun(fun), eof(eof)
         {
         }
 
@@ -188,11 +184,19 @@ std::unique_ptr<Source> sinkToSource(
 
         size_t read(unsigned char * data, size_t len) override
         {
-            if (!coro) { eof(); abort(); }
+            if (!coro)
+                coro = coro_t::pull_type([&](coro_t::push_type & yield) {
+                    LambdaSink sink([&](const unsigned char * data, size_t len) {
+                            if (len) yield(std::string((const char *) data, len));
+                        });
+                    fun(sink);
+                });
+
+            if (!*coro) { eof(); abort(); }
 
             if (pos == cur.size()) {
-                if (!cur.empty()) coro();
-                cur = coro.get();
+                if (!cur.empty()) (*coro)();
+                cur = coro->get();
                 pos = 0;
             }
 
@@ -268,16 +272,17 @@ void readPadding(size_t len, Source & source)
 size_t readString(unsigned char * buf, size_t max, Source & source)
 {
     auto len = readNum<size_t>(source);
-    if (len > max) throw Error("string is too long");
+    if (len > max) throw SerialisationError("string is too long");
     source(buf, len);
     readPadding(len, source);
     return len;
 }
 
 
-string readString(Source & source)
+string readString(Source & source, size_t max)
 {
     auto len = readNum<size_t>(source);
+    if (len > max) throw SerialisationError("string is too long");
     std::string res(len, 0);
     source((unsigned char*) res.data(), len);
     readPadding(len, source);
diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index 4b6ad5da5b9c..969e4dff383d 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -284,7 +284,7 @@ inline uint64_t readLongLong(Source & source)
 
 void readPadding(size_t len, Source & source);
 size_t readString(unsigned char * buf, size_t max, Source & source);
-string readString(Source & source);
+string readString(Source & source, size_t max = std::numeric_limits<size_t>::max());
 template<class T> T readStrings(Source & source);
 
 Source & operator >> (Source & in, string & s);
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 03f0be705c1d..6e4536e6e4ea 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -496,6 +496,15 @@ Path getConfigDir()
     return configDir;
 }
 
+std::vector<Path> getConfigDirs()
+{
+    Path configHome = getConfigDir();
+    string configDirs = getEnv("XDG_CONFIG_DIRS");
+    std::vector<Path> result = tokenizeString<std::vector<string>>(configDirs, ":");
+    result.insert(result.begin(), configHome);
+    return result;
+}
+
 
 Path getDataDir()
 {
@@ -927,6 +936,7 @@ pid_t startProcess(std::function<void()> fun, const ProcessOptions & options)
                 throw SysError("setting death signal");
 #endif
             restoreAffinity();
+            restoreMountNamespace();
             fun();
         } catch (std::exception & e) {
             try {
@@ -1495,4 +1505,26 @@ std::unique_ptr<InterruptCallback> createInterruptCallback(std::function<void()>
     return std::unique_ptr<InterruptCallback>(res.release());
 }
 
+static AutoCloseFD fdSavedMountNamespace;
+
+void saveMountNamespace()
+{
+#if __linux__
+    std::once_flag done;
+    std::call_once(done, []() {
+        fdSavedMountNamespace = open("/proc/self/ns/mnt", O_RDONLY);
+        if (!fdSavedMountNamespace)
+            throw SysError("saving parent mount namespace");
+    });
+#endif
+}
+
+void restoreMountNamespace()
+{
+#if __linux__
+    if (fdSavedMountNamespace && setns(fdSavedMountNamespace.get(), CLONE_NEWNS) == -1)
+        throw SysError("restoring parent mount namespace");
+#endif
+}
+
 }
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index fc25d27758c7..2689cbd8b412 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -131,6 +131,9 @@ Path getCacheDir();
 /* Return $XDG_CONFIG_HOME or $HOME/.config. */
 Path getConfigDir();
 
+/* Return the directories to search for user configuration files */
+std::vector<Path> getConfigDirs();
+
 /* Return $XDG_DATA_HOME or $HOME/.local/share. */
 Path getDataDir();
 
@@ -511,4 +514,13 @@ typedef std::function<bool(const Path & path)> PathFilter;
 extern PathFilter defaultPathFilter;
 
 
+/* Save the current mount namespace. Ignored if called more than
+   once. */
+void saveMountNamespace();
+
+/* Restore the mount namespace saved by saveMountNamespace(). Ignored
+   if saveMountNamespace() was never called. */
+void restoreMountNamespace();
+
+
 }