Split up util.{hh,cc}

All OS and IO operations should be moved out, leaving only some misc
portable pure functions.

This is useful to avoid copious CPP when doing things like Windows and
Emscripten ports.

Newly exposed functions to break cycles:

 - `restoreSignals`
 - `updateWindowSize`

src/libstore/binary-cache-store.cc

@@ -11,6 +11,7 @@
 #include "nar-accessor.hh"
 #include "thread-pool.hh"
 #include "callback.hh"
+#include "signals.hh"
 
 #include <chrono>
 #include <future>

src/libstore/build/child.cc

@@ -0,0 +1,37 @@
+#include "child.hh"
+#include "current-process.hh"
+#include "logging.hh"
+
+#include <fcntl.h>
+#include <unistd.h>
+
+namespace nix {
+
+void commonChildInit()
+{
+    logger = makeSimpleLogger();
+
+    const static std::string pathNullDevice = "/dev/null";
+    restoreProcessContext(false);
+
+    /* Put the child in a separate session (and thus a separate
+       process group) so that it has no controlling terminal (meaning
+       that e.g. ssh cannot open /dev/tty) and it doesn't receive
+       terminal signals. */
+    if (setsid() == -1)
+        throw SysError("creating a new session");
+
+    /* Dup stderr to stdout. */
+    if (dup2(STDERR_FILENO, STDOUT_FILENO) == -1)
+        throw SysError("cannot dup stderr into stdout");
+
+    /* Reroute stdin to /dev/null. */
+    int fdDevNull = open(pathNullDevice.c_str(), O_RDWR);
+    if (fdDevNull == -1)
+        throw SysError("cannot open '%1%'", pathNullDevice);
+    if (dup2(fdDevNull, STDIN_FILENO) == -1)
+        throw SysError("cannot dup null device into stdin");
+    close(fdDevNull);
+}
+
+}

src/libstore/build/child.hh

@@ -0,0 +1,11 @@
+#pragma once
+///@file
+
+namespace nix {
+
+/**
+ * Common initialisation performed in child processes.
+ */
+void commonChildInit();
+
+}

src/libstore/build/hook-instance.cc

@@ -1,5 +1,7 @@
 #include "globals.hh"
 #include "hook-instance.hh"
+#include "file-system.hh"
+#include "child.hh"
 
 namespace nix {
 

src/libstore/build/hook-instance.hh

@@ -3,6 +3,7 @@
 
 #include "logging.hh"
 #include "serialise.hh"
+#include "processes.hh"
 
 namespace nix {
 

src/libstore/build/local-derivation-goal.cc

@@ -15,7 +15,10 @@
 #include "json-utils.hh"
 #include "cgroup.hh"
 #include "personality.hh"
+#include "current-process.hh"
 #include "namespaces.hh"
+#include "child.hh"
+#include "unix-domain-socket.hh"
 
 #include <regex>
 #include <queue>

src/libstore/build/local-derivation-goal.hh

@@ -3,6 +3,7 @@
 
 #include "derivation-goal.hh"
 #include "local-store.hh"
+#include "processes.hh"
 
 namespace nix {
 

src/libstore/build/worker.cc

@@ -4,6 +4,7 @@
 #include "drv-output-substitution-goal.hh"
 #include "local-derivation-goal.hh"
 #include "hook-instance.hh"
+#include "signals.hh"
 
 #include <poll.h>
 

src/libstore/common-protocol.cc

@@ -1,5 +1,4 @@
 #include "serialise.hh"
-#include "util.hh"
 #include "path-with-outputs.hh"
 #include "store-api.hh"
 #include "build-result.hh"

src/libstore/crypto.cc

@@ -1,4 +1,5 @@
 #include "crypto.hh"
+#include "file-system.hh"
 #include "util.hh"
 #include "globals.hh"
 

src/libstore/derived-path-map.cc

@@ -1,4 +1,5 @@
 #include "derived-path-map.hh"
+#include "util.hh"
 
 namespace nix {
 

src/libstore/derived-path-map.hh

@@ -1,4 +1,5 @@
 #pragma once
+///@file
 
 #include "types.hh"
 #include "derived-path.hh"

src/libstore/derived-path.hh

@@ -1,10 +1,10 @@
 #pragma once
 ///@file
 
-#include "util.hh"
 #include "path.hh"
 #include "outputs-spec.hh"
 #include "comparator.hh"
+#include "config.hh"
 
 #include <variant>
 

src/libstore/filetransfer.cc

@@ -1,11 +1,12 @@
 #include "filetransfer.hh"
-#include "util.hh"
+#include "namespaces.hh"
 #include "globals.hh"
 #include "store-api.hh"
 #include "s3.hh"
 #include "compression.hh"
 #include "finally.hh"
 #include "callback.hh"
+#include "signals.hh"
 
 #if ENABLE_S3
 #include <aws/core/client/ClientConfiguration.h>

src/libstore/gc.cc

@@ -2,6 +2,13 @@
 #include "globals.hh"
 #include "local-store.hh"
 #include "finally.hh"
+#include "unix-domain-socket.hh"
+#include "signals.hh"
+
+#if !defined(__linux__)
+// For shelling out to lsof
+# include "processes.hh"
+#endif
 
 #include <functional>
 #include <queue>

src/libstore/globals.cc

@@ -1,7 +1,8 @@
 #include "globals.hh"
-#include "util.hh"
+#include "current-process.hh"
 #include "archive.hh"
 #include "args.hh"
+#include "users.hh"
 #include "abstract-setting-to-json.hh"
 #include "compute-levels.hh"
 
@@ -17,9 +18,13 @@
 #include <sodium/core.h>
 
 #ifdef __GLIBC__
-#include <gnu/lib-names.h>
-#include <nss.h>
-#include <dlfcn.h>
+# include <gnu/lib-names.h>
+# include <nss.h>
+# include <dlfcn.h>
+#endif
+
+#if __APPLE__
+# include "processes.hh"
 #endif
 
 #include "config-impl.hh"

src/libstore/globals.hh

@@ -3,7 +3,7 @@
 
 #include "types.hh"
 #include "config.hh"
-#include "util.hh"
+#include "environment-variables.hh"
 #include "experimental-features.hh"
 
 #include <map>

src/libstore/local-store.cc

@@ -10,6 +10,7 @@
 #include "topo-sort.hh"
 #include "finally.hh"
 #include "compression.hh"
+#include "signals.hh"
 
 #include <iostream>
 #include <algorithm>

src/libstore/local-store.hh

@@ -7,7 +7,6 @@
 #include "store-api.hh"
 #include "indirect-root-store.hh"
 #include "sync.hh"
-#include "util.hh"
 
 #include <chrono>
 #include <future>

src/libstore/lock.cc

@@ -1,4 +1,5 @@
 #include "lock.hh"
+#include "file-system.hh"
 #include "globals.hh"
 #include "pathlocks.hh"
 

src/libstore/machines.cc

@@ -1,5 +1,4 @@
 #include "machines.hh"
-#include "util.hh"
 #include "globals.hh"
 #include "store-api.hh"
 

src/libstore/nar-info-disk-cache.cc

@@ -1,4 +1,5 @@
 #include "nar-info-disk-cache.hh"
+#include "users.hh"
 #include "sync.hh"
 #include "sqlite.hh"
 #include "globals.hh"

src/libstore/optimise-store.cc

@@ -1,6 +1,6 @@
-#include "util.hh"
 #include "local-store.hh"
 #include "globals.hh"
+#include "signals.hh"
 
 #include <cstdlib>
 #include <cstring>

src/libstore/path-references.cc

@@ -1,6 +1,5 @@
 #include "path-references.hh"
 #include "hash.hh"
-#include "util.hh"
 #include "archive.hh"
 
 #include <map>

src/libstore/path-references.hh

@@ -1,4 +1,5 @@
 #pragma once
+///@file
 
 #include "references.hh"
 #include "path.hh"

src/libstore/pathlocks.cc

@@ -1,6 +1,7 @@
 #include "pathlocks.hh"
 #include "util.hh"
 #include "sync.hh"
+#include "signals.hh"
 
 #include <cerrno>
 #include <cstdlib>

src/libstore/pathlocks.hh

@@ -1,7 +1,7 @@
 #pragma once
 ///@file
 
-#include "util.hh"
+#include "file-descriptor.hh"
 
 namespace nix {
 

src/libstore/profiles.cc

@@ -1,7 +1,7 @@
 #include "profiles.hh"
 #include "store-api.hh"
 #include "local-fs-store.hh"
-#include "util.hh"
+#include "users.hh"
 
 #include <sys/types.h>
 #include <sys/stat.h>

src/libstore/remote-store-connection.hh

@@ -1,3 +1,6 @@
+#pragma once
+///@file
+
 #include "remote-store.hh"
 #include "worker-protocol.hh"
 #include "pool.hh"

src/libstore/serve-protocol.cc

@@ -1,5 +1,4 @@
 #include "serialise.hh"
-#include "util.hh"
 #include "path-with-outputs.hh"
 #include "store-api.hh"
 #include "build-result.hh"

src/libstore/sqlite.cc

@@ -2,6 +2,7 @@
 #include "globals.hh"
 #include "util.hh"
 #include "url.hh"
+#include "signals.hh"
 
 #include <sqlite3.h>
 

src/libstore/ssh.cc

@@ -1,5 +1,8 @@
 #include "ssh.hh"
 #include "finally.hh"
+#include "current-process.hh"
+#include "environment-variables.hh"
+#include "util.hh"
 
 namespace nix {
 

src/libstore/ssh.hh

@@ -1,8 +1,9 @@
 #pragma once
 ///@file
 
-#include "util.hh"
 #include "sync.hh"
+#include "processes.hh"
+#include "file-system.hh"
 
 namespace nix {
 

src/libstore/store-api.cc

@@ -14,6 +14,8 @@
 // FIXME this should not be here, see TODO below on
 // `addMultipleToStore`.
 #include "worker-protocol.hh"
+#include "signals.hh"
+#include "users.hh"
 
 #include <nlohmann/json.hpp>
 #include <regex>

src/libstore/tests/machines.cc

@@ -1,5 +1,7 @@
 #include "machines.hh"
 #include "globals.hh"
+#include "file-system.hh"
+#include "util.hh"
 
 #include <gmock/gmock-matchers.h>
 

src/libstore/tests/protocol.hh

@@ -1,3 +1,6 @@
+#pragma once
+///@file
+
 #include <nlohmann/json.hpp>
 #include <gtest/gtest.h>
 

src/libstore/uds-remote-store.cc

@@ -1,4 +1,5 @@
 #include "uds-remote-store.hh"
+#include "unix-domain-socket.hh"
 #include "worker-protocol.hh"
 
 #include <sys/types.h>

src/libstore/worker-protocol.cc

@@ -1,5 +1,4 @@
 #include "serialise.hh"
-#include "util.hh"
 #include "path-with-outputs.hh"
 #include "store-api.hh"
 #include "build-result.hh"