#pragma once

#include "types.hh"

#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>
#include <signal.h>
#include <functional>

#include <cstdio>


namespace nix {


#define foreach(it_type, it, collection)                                \
    for (it_type it = (collection).begin(); it != (collection).end(); ++it)

#define foreach_reverse(it_type, it, collection)                                \
    for (it_type it = (collection).rbegin(); it != (collection).rend(); ++it)


/* Return an environment variable. */
string getEnv(const string & key, const string & def = "");

/* Return an absolutized path, resolving paths relative to the
   specified directory, or the current directory otherwise.  The path
   is also canonicalised. */
Path absPath(Path path, Path dir = "");

/* Canonicalise a path by removing all `.' or `..' components and
   double or trailing slashes.  Optionally resolves all symlink
   components such that each component of the resulting path is</td></tr></table>
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<div class='content'><div id='summary'><pre>
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2017 Sou Bunnbu &lt;iyzsong@member.fsf.org&gt;
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see &lt;http://www.gnu.org/licenses/&gt;.

(define-module (gnu services sysctl)
  #:use-module (gnu services)
  #:use-module (gnu services shepherd)
  #:use-module (gnu packages linux)
  #:use-module (guix gexp)
  #:use-module (guix records)
  #:use-module (srfi srfi-1)
  #:use-module (ice-9 match)
  #:export (sysctl-configuration
            sysctl-configuration-sysctl
            sysctl-configuration-settings
            sysctl-service-type
            %default-sysctl-settings))


;;;
;;; System Control Service.
;;;

(define %default-sysctl-settings
  ;; Default kernel parameters enabled with sysctl.
  &apos;((&quot;fs.protected_hardlinks&quot; . &quot;1&quot;)
    (&quot;fs.protected_symlinks&quot; . &quot;1&quot;)))

(define-record-type* &lt;sysctl-configuration&gt;
  sysctl-configuration make-sysctl-configuration
  sysctl-configuration?
  (sysctl   sysctl-configuration-sysctl    ; path of the &apos;sysctl&apos; command
            (default (file-append procps &quot;/sbin/sysctl&quot;)))
  (settings sysctl-configuration-settings  ; alist of string pairs
            (default %default-sysctl-settings)))

(define (sysctl-configuration-settings-&gt;sysctl.conf settings)
  &quot;Return a file for @command{sysctl} to set kernel parameters as specified by
@var{settings}.&quot;
  (apply mixed-text-file &quot;sysctl.conf&quot;
         (append-map (match-lambda
                       ((key . value)
                        (list key &quot;=&quot; value &quot;\n&quot;)))
                     settings)))

(define sysctl-shepherd-service
  (match-lambda
    (($ &lt;sysctl-configuration&gt; sysctl settings)
     (let ((sysctl.conf
            (sysctl-configuration-settings-&gt;sysctl.conf settings)))
       (shepherd-service
        (documentation &quot;Configure kernel parameters at boot.&quot;)
        (provision &apos;(sysctl))
        (start #~(lambda _
                   (zero? (system* #$sysctl &quot;--load&quot; #$sysctl.conf))))
        (one-shot? #t))))))

(define sysctl-service-type
  (service-type
   (name &apos;sysctl)
   (extensions
    (list (service-extension shepherd-root-service-type
                             (compose list sysctl-shepherd-service))))
   (compose concatenate)
   (extend (lambda (config settings)
             (sysctl-configuration
              (inherit config)
              (settings (append (sysctl-configuration-settings config)
                                settings)))))
   (default-value (sysctl-configuration))
   (description &quot;Set Linux kernel parameters under @file{/proc/sys} at system
startup time.&quot;)))
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ic:
    AutoCloseFD readSide, writeSide;
    void create();
};


class AutoCloseDir
{
    DIR * dir;
public:
    AutoCloseDir();
    AutoCloseDir(DIR * dir);
    ~AutoCloseDir();
    void operator =(DIR * dir);
    operator DIR *();
    void close();
};


class Pid
{
    pid_t pid;
    bool separatePG;
    int killSignal;
public:
    Pid();
    Pid(pid_t pid);
    ~Pid();
    void operator =(pid_t pid);
    operator pid_t();
    void kill(bool quiet = false);
    int wait(bool block);
    void setSeparatePG(bool separatePG);
    void setKillSignal(int signal);
};

/* An "agent" is a helper program that runs in the background and that we talk
   to over pipes, such as the "guix offload" program.  */
struct Agent
{
    /* Pipes for talking to the agent. */
    Pipe toAgent;

    /* Pipe for the agent's standard output/error. */
    Pipe fromAgent;

    /* Pipe for build standard output/error--e.g., for build processes started
       by "guix offload".  */
    Pipe builderOut;

    /* The process ID of the agent. */
    Pid pid;

    /* The command and arguments passed to the agent.  */
    Agent(const string &command, const Strings &args);

    ~Agent();
};


/* 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. */
pid_t startProcess(std::function<void()> fun, bool dieWithParent = true,
    const string & errorPrefix = "error: ", bool runExitHandlers = false);


/* Run a program and return its stdout in a string (i.e., like the
   shell backtick operator). */
string runProgram(Path program, bool searchPath = false,
    const Strings & args = Strings());

MakeError(ExecError, Error)

/* Convert a list of strings to a null-terminated vector of char
   *'s. The result must not be accessed beyond the lifetime of the
   list of strings. */
std::vector<char *> stringsToCharPtrs(const Strings & ss);

/* Close all file descriptors except stdin, stdout, stderr, and those
   listed in the given set.  Good practice in child processes. */
void closeMostFDs(const set<int> & exceptions);

/* Set the close-on-exec flag for the given file descriptor. */
void closeOnExec(int fd);

/* Common initialisation performed in child processes. */
void commonChildInit(Pipe & logPipe);

/* User interruption. */

extern volatile sig_atomic_t _isInterrupted;

void _interrupted();

void inline checkInterrupt()
{
    if (_isInterrupted) _interrupted();
}

MakeError(Interrupted, BaseError)


/* String tokenizer. */
template<class C> C tokenizeString(const string & s, const string & separators = " \t\n\r");


/* Concatenate the given strings with a separator between the
   elements. */
string concatStringsSep(const string & sep, const Strings & ss);
string concatStringsSep(const string & sep, const StringSet & ss);


/* Remove trailing whitespace from a string. */
string chomp(const string & s);


/* Convert the exit status of a child as returned by wait() into an
   error string. */
string statusToString(int status);

bool statusOk(int status);


/* Parse a string into an integer. */
template<class N> bool string2Int(const string & s, N & n)
{
    std::istringstream str(s);
    str >> n;
    return str && str.get() == EOF;
}


/* Return true iff `s' ends in `suffix'. */
bool hasSuffix(const string & s, const string & suffix);


/* Read string `s' from stream `str'. */
void expect(std::istream & str, const string & s);

MakeError(FormatError, Error)


/* Read a C-style string from stream `str'. */
string parseString(std::istream & str);


/* Utility function used to parse legacy ATerms. */
bool endOfList(std::istream & str);


/* Exception handling in destructors: print an error message, then
   ignore the exception. */
void ignoreException();


}