util.{hh,cc}: Split out processes.{hh,cc}

Change-Id: I39280dc40ca3f7f9007bc6c898ffcf760e2238b7

1 files changed, 115 insertions, 0 deletions

diff --git a/src/libutil/processes.hh b/src/libutil/processes.hh
new file mode 100644
index 000000000..91a4edfd2
--- /dev/null
+++ b/src/libutil/processes.hh
@@ -0,0 +1,115 @@
+#pragma once
+///@file
+
+#include "types.hh"
+#include "error.hh"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <signal.h>
+
+#include <boost/lexical_cast.hpp>
+
+#include <functional>
+#include <map>
+#include <optional>
+
+namespace nix {
+
+struct Sink;
+struct Source;
+
+class Pid
+{
+    pid_t pid = -1;
+    bool separatePG = false;
+    int killSignal = SIGKILL;
+public:
+    Pid();
+    Pid(pid_t pid);
+    ~Pid() noexcept(false);
+    void operator =(pid_t pid);
+    operator pid_t();
+    int kill();
+    int wait();
+
+    void setSeparatePG(bool separatePG);
+    void setKillSignal(int signal);
+    pid_t release();
+};
+
+/**
+ * Kill all processes running under the specified uid by sending them
+ * a SIGKILL.
+ */
+void killUser(uid_t uid);
+
+
+/**
+ * Fork a process that runs the given function, and return the child
+ * pid to the caller.
+ */
+struct ProcessOptions
+{
+    std::string errorPrefix = "";
+    bool dieWithParent = true;
+    bool runExitHandlers = false;
+    /**
+     * use clone() with the specified flags (Linux only)
+     */
+    int cloneFlags = 0;
+};
+
+pid_t startProcess(std::function<void()> fun, const ProcessOptions & options = ProcessOptions());
+
+
+/**
+ * Run a program and return its stdout in a string (i.e., like the
+ * shell backtick operator).
+ */
+std::string runProgram(Path program, bool searchPath = false,
+    const Strings & args = Strings(),
+    const std::optional<std::string> & input = {}, bool isInteractive = false);
+
+struct RunOptions
+{
+    Path program;
+    bool searchPath = true;
+    Strings args;
+    std::optional<uid_t> uid;
+    std::optional<uid_t> gid;
+    std::optional<Path> chdir;
+    std::optional<std::map<std::string, std::string>> environment;
+    std::optional<std::string> input;
+    Source * standardIn = nullptr;
+    Sink * standardOut = nullptr;
+    bool mergeStderrToStdout = false;
+    bool isInteractive = false;
+};
+
+std::pair<int, std::string> runProgram(RunOptions && options);
+
+void runProgram2(const RunOptions & options);
+
+class ExecError : public Error
+{
+public:
+    int status;
+
+    template<typename... Args>
+    ExecError(int status, const Args & ... args)
+        : Error(args...), status(status)
+    { }
+};
+
+/**
+ * Convert the exit status of a child as returned by wait() into an
+ * error string.
+ */
+std::string statusToString(int status);
+
+bool statusOk(int status);
+
+}