util.{hh,cc}: Split out current-process.{hh,cc}

Change-Id: I77095b9d37e85310075bada7a076ccd482c28e47

6 files changed, 150 insertions, 112 deletions

diff --git a/src/libutil/current-process.cc b/src/libutil/current-process.cc
new file mode 100644
index 000000000..826e25547
--- /dev/null
+++ b/src/libutil/current-process.cc
@@ -0,0 +1,109 @@
+#include "current-process.hh"
+#include "file-system.hh"
+#include "logging.hh"
+#include "signals.hh"
+#include "util.hh"
+
+#ifdef __APPLE__
+# include <mach-o/dyld.h>
+#endif
+
+#if __linux__
+# include <sys/resource.h>
+#endif
+
+#include <sys/mount.h>
+#include <cgroup.hh>
+
+namespace nix {
+
+unsigned int getMaxCPU()
+{
+    #if __linux__
+    try {
+        auto cgroupFS = getCgroupFS();
+        if (!cgroupFS) return 0;
+
+        auto cgroups = getCgroups("/proc/self/cgroup");
+        auto cgroup = cgroups[""];
+        if (cgroup == "") return 0;
+
+        auto cpuFile = *cgroupFS + "/" + cgroup + "/cpu.max";
+
+        auto cpuMax = readFile(cpuFile);
+        auto cpuMaxParts = tokenizeString<std::vector<std::string>>(cpuMax, " \n");
+
+        if (cpuMaxParts.size() != 2) {
+            return 0;
+        }
+
+        auto quota = cpuMaxParts[0];
+        auto period = cpuMaxParts[1];
+        if (quota != "max")
+                return std::ceil(std::stoi(quota) / std::stof(period));
+    } catch (Error &) { ignoreException(lvlDebug); }
+    #endif
+
+    return 0;
+}
+
+rlim_t savedStackSize = 0;
+
+void setStackSize(rlim_t stackSize)
+{
+    struct rlimit limit;
+    if (getrlimit(RLIMIT_STACK, &limit) == 0 && limit.rlim_cur < stackSize) {
+        savedStackSize = limit.rlim_cur;
+        limit.rlim_cur = std::min(stackSize, limit.rlim_max);
+        if (setrlimit(RLIMIT_STACK, &limit) != 0) {
+            logger->log(
+                lvlError,
+                HintFmt(
+                    "Failed to increase stack size from %1% to %2% (maximum allowed stack size: %3%): %4%",
+                    savedStackSize,
+                    stackSize,
+                    limit.rlim_max,
+                    std::strerror(errno)
+                ).str()
+            );
+        }
+    }
+}
+
+void restoreProcessContext(bool restoreMounts)
+{
+    restoreSignals();
+    if (restoreMounts) {
+        restoreMountNamespace();
+    }
+
+    if (savedStackSize) {
+        struct rlimit limit;
+        if (getrlimit(RLIMIT_STACK, &limit) == 0) {
+            limit.rlim_cur = savedStackSize;
+            setrlimit(RLIMIT_STACK, &limit);
+        }
+    }
+}
+
+std::optional<Path> getSelfExe()
+{
+    static auto cached = []() -> std::optional<Path>
+    {
+        #if __linux__
+        return readLink("/proc/self/exe");
+        #elif __APPLE__
+        char buf[1024];
+        uint32_t size = sizeof(buf);
+        if (_NSGetExecutablePath(buf, &size) == 0)
+            return buf;
+        else
+            return std::nullopt;
+        #else
+        return std::nullopt;
+        #endif
+    }();
+    return cached;
+}
+
+}
diff --git a/src/libutil/current-process.hh b/src/libutil/current-process.hh
new file mode 100644
index 000000000..8d5a2791d
--- /dev/null
+++ b/src/libutil/current-process.hh
@@ -0,0 +1,37 @@
+#pragma once
+///@file
+
+#include <optional>
+#include <sys/resource.h>
+
+#include "types.hh"
+
+namespace nix {
+
+/**
+ * If cgroups are active, attempt to calculate the number of CPUs available.
+ * If cgroups are unavailable or if cpu.max is set to "max", return 0.
+ */
+unsigned int getMaxCPU();
+
+
+/**
+ * Change the stack size.
+ */
+void setStackSize(rlim_t stackSize);
+
+
+/**
+ * Restore the original inherited Unix process context (such as signal
+ * masks, stack size).
+
+ * See startSignalHandlerThread(), saveSignalMask().
+ */
+void restoreProcessContext(bool restoreMounts = true);
+
+/**
+ * @return the path of the current executable.
+ */
+std::optional<Path> getSelfExe();
+
+}
diff --git a/src/libutil/meson.build b/src/libutil/meson.build
index 34715b25e..ef4270066 100644
--- a/src/libutil/meson.build
+++ b/src/libutil/meson.build
@@ -6,6 +6,7 @@ libutil_sources = files(
   'compression.cc',
   'compute-levels.cc',
   'config.cc',
+  'current-process.cc',
   'english.cc',
   'environment-variables.cc',
   'error.cc',
@@ -56,6 +57,7 @@ libutil_headers = files(
   'compute-levels.hh',
   'config-impl.hh',
   'config.hh',
+  'current-process.hh',
   'english.hh',
   'environment-variables.hh',
   'error.hh',
diff --git a/src/libutil/processes.cc b/src/libutil/processes.cc
index 8d1b119b0..8639a77f8 100644
--- a/src/libutil/processes.cc
+++ b/src/libutil/processes.cc
@@ -1,3 +1,4 @@
+#include "current-process.hh"
 #include "environment-variables.hh"
 #include "finally.hh"
 #include "logging.hh"
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 702db2afb..7f9413f8d 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -1,5 +1,6 @@
 #include "util.hh"
 #include "processes.hh"
+#include "current-process.hh"
 
 #include "sync.hh"
 #include "finally.hh"
@@ -148,59 +149,11 @@ Path createNixStateDir()
 }
 
 
-std::optional<Path> getSelfExe()
-{
-    static auto cached = []() -> std::optional<Path>
-    {
-        #if __linux__
-        return readLink("/proc/self/exe");
-        #elif __APPLE__
-        char buf[1024];
-        uint32_t size = sizeof(buf);
-        if (_NSGetExecutablePath(buf, &size) == 0)
-            return buf;
-        else
-            return std::nullopt;
-        #else
-        return std::nullopt;
-        #endif
-    }();
-    return cached;
-}
 
 
 
 //////////////////////////////////////////////////////////////////////
 
-unsigned int getMaxCPU()
-{
-    #if __linux__
-    try {
-        auto cgroupFS = getCgroupFS();
-        if (!cgroupFS) return 0;
-
-        auto cgroups = getCgroups("/proc/self/cgroup");
-        auto cgroup = cgroups[""];
-        if (cgroup == "") return 0;
-
-        auto cpuFile = *cgroupFS + "/" + cgroup + "/cpu.max";
-
-        auto cpuMax = readFile(cpuFile);
-        auto cpuMaxParts = tokenizeString<std::vector<std::string>>(cpuMax, " \n");
-
-        if (cpuMaxParts.size() != 2) {
-            return 0;
-        }
-
-        auto quota = cpuMaxParts[0];
-        auto period = cpuMaxParts[1];
-        if (quota != "max")
-                return std::ceil(std::stoi(quota) / std::stof(period));
-    } catch (Error &) { ignoreException(lvlDebug); }
-    #endif
-
-    return 0;
-}
 
 //////////////////////////////////////////////////////////////////////
 
@@ -454,28 +407,6 @@ std::pair<std::string_view, std::string_view> getLine(std::string_view s)
 //////////////////////////////////////////////////////////////////////
 
 
-rlim_t savedStackSize = 0;
-
-void setStackSize(rlim_t stackSize)
-{
-    struct rlimit limit;
-    if (getrlimit(RLIMIT_STACK, &limit) == 0 && limit.rlim_cur < stackSize) {
-        savedStackSize = limit.rlim_cur;
-        limit.rlim_cur = std::min(stackSize, limit.rlim_max);
-        if (setrlimit(RLIMIT_STACK, &limit) != 0) {
-            logger->log(
-                lvlError,
-                HintFmt(
-                    "Failed to increase stack size from %1% to %2% (maximum allowed stack size: %3%): %4%",
-                    savedStackSize,
-                    stackSize,
-                    limit.rlim_max,
-                    std::strerror(errno)
-                ).str()
-            );
-        }
-    }
-}
 
 #if __linux__
 static AutoCloseFD fdSavedMountNamespace;
@@ -528,22 +459,6 @@ void unshareFilesystem()
 #endif
 }
 
-void restoreProcessContext(bool restoreMounts)
-{
-    restoreSignals();
-    if (restoreMounts) {
-        restoreMountNamespace();
-    }
-
-    if (savedStackSize) {
-        struct rlimit limit;
-        if (getrlimit(RLIMIT_STACK, &limit) == 0) {
-            limit.rlim_cur = savedStackSize;
-            setrlimit(RLIMIT_STACK, &limit);
-        }
-    }
-}
-
 AutoCloseFD createUnixDomainSocket()
 {
     AutoCloseFD fdSocket{socket(PF_UNIX, SOCK_STREAM
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 8d1900131..de5f0a2ee 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -72,11 +72,6 @@ std::vector<Path> getConfigDirs();
 Path getDataDir();
 
 /**
- * @return the path of the current executable.
- */
-std::optional<Path> getSelfExe();
-
-/**
  * @return $XDG_STATE_HOME or $HOME/.local/state.
  *
  * @note Not to be confused with settings.nixStateDir.
@@ -92,27 +87,6 @@ Path createNixStateDir();
 
 
 /**
- * If cgroups are active, attempt to calculate the number of CPUs available.
- * If cgroups are unavailable or if cpu.max is set to "max", return 0.
- */
-unsigned int getMaxCPU();
-
-
-/**
- * Change the stack size.
- */
-void setStackSize(rlim_t stackSize);
-
-
-/**
- * Restore the original inherited Unix process context (such as signal
- * masks, stack size).
-
- * See startSignalHandlerThread(), saveSignalMask().
- */
-void restoreProcessContext(bool restoreMounts = true);
-
-/**
  * Save the current mount namespace. Ignored if called more than
  * once.
  */