cups/patches/cups-1.4.7-systemd-socket.patch

From 1db0a48375836c7e93ac30649007c2391be8b3b2 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 4 Jul 2011 01:37:01 +0200
Subject: [PATCH] systemd: add systemd socket activation and unit files

On newer Linux machines systemd supports launchd-style socket
activation. This patch adds support for this mechanism and also adds
systemd unit files as appropriate to hook this up with systemd.

This includes an MIT-licensed drop-in file that implements the most
basic interfaces needed to get the file descriptors from systemd. Most
of the systemd and Linux-specific code compiles to NOPs on other
systems.

Three triggers to start CUPS are defined: a) if new printer hardware is
plugged in, b) when a client accesses the CUPS socket and c) when a
spool file resides in /var/spool/cups.
---
 Makedefs.in                    |    2 +
 config-scripts/cups-systemd.m4 |   25 ++
 configure.in                   |    4 +
 data/Makefile                  |    9 +
 data/cups.path.in              |    8 +
 data/cups.service.in           |    9 +
 data/cups.socket.in            |    9 +
 scheduler/Makefile             |    9 +
 scheduler/main.c               |  107 ++++++++
 scheduler/sd-daemon.c          |  520 ++++++++++++++++++++++++++++++++++++++++
 scheduler/sd-daemon.h          |  277 +++++++++++++++++++++
 11 files changed, 979 insertions(+), 0 deletions(-)
 create mode 100644 config-scripts/cups-systemd.m4
 create mode 100644 data/cups.path.in
 create mode 100644 data/cups.service.in
 create mode 100644 data/cups.socket.in
 create mode 100644 scheduler/sd-daemon.c
 create mode 100644 scheduler/sd-daemon.h

diff --git a/Makedefs.in b/Makedefs.in
index 654eea4..02c43b6 100644
--- a/Makedefs.in
+++ b/Makedefs.in
@@ -143,6 +143,7 @@ CXXFLAGS	=	@CPPFLAGS@ @CXXFLAGS@
 CXXLIBS		=	@CXXLIBS@
 DBUS_NOTIFIER	=	@DBUS_NOTIFIER@
 DBUS_NOTIFIERLIBS =	@DBUS_NOTIFIERLIBS@
+SYSTEMD_UNITS   =       @SYSTEMD_UNITS@
 DNSSD_BACKEND	=	@DNSSD_BACKEND@
 DSOFLAGS	=	-L../cups @DSOFLAGS@
 DSOLIBS		=	@DSOLIBS@ $(COMMONLIBS)
@@ -267,6 +268,7 @@ PAMFILE		=	@PAMFILE@
 
 DEFAULT_LAUNCHD_CONF =	@DEFAULT_LAUNCHD_CONF@
 DBUSDIR		=	@DBUSDIR@
+SYSTEMDUNITDIR  =       $(BUILDROOT)@systemdsystemunitdir@
 
 
 #
diff --git a/config-scripts/cups-systemd.m4 b/config-scripts/cups-systemd.m4
new file mode 100644
index 0000000..fead8a9
--- /dev/null
+++ b/config-scripts/cups-systemd.m4
@@ -0,0 +1,25 @@
+dnl
+dnl "$Id$"
+dnl
+dnl   systemd stuff for CUPS.
+
+dnl Find whether systemd is available
+
+AC_ARG_WITH([systemdsystemunitdir],
+        AS_HELP_STRING([--with-systemdsystemunitdir=DIR], [Directory for systemd service files]),
+        [], [with_systemdsystemunitdir=$($PKGCONFIG --variable=systemdsystemunitdir systemd)])
+if test "x$with_systemdsystemunitdir" != xno; then
+        AC_SUBST([systemdsystemunitdir], [$with_systemdsystemunitdir])
+fi
+
+if test -n "$with_systemdsystemunitdir" -a "x$with_systemdsystemunitdir" != xno ; then
+        SYSTEMD_UNITS="cups.service cups.socket cups.path"
+else
+        SYSTEMD_UNITS=""
+fi
+
+AC_SUBST(SYSTEMD_UNITS)
+
+dnl
+dnl "$Id$"
+dnl
diff --git a/configure.in b/configure.in
index 560f4f8..b0c19a9 100644
--- a/configure.in
+++ b/configure.in
@@ -37,6 +37,7 @@ sinclude(config-scripts/cups-pam.m4)
 sinclude(config-scripts/cups-largefile.m4)
 sinclude(config-scripts/cups-dnssd.m4)
 sinclude(config-scripts/cups-launchd.m4)
+sinclude(config-scripts/cups-systemd.m4)
 sinclude(config-scripts/cups-defaults.m4)
 sinclude(config-scripts/cups-pdf.m4)
 sinclude(config-scripts/cups-scripting.m4)
@@ -71,6 +72,9 @@ AC_OUTPUT(Makedefs
 	  conf/snmp.conf
 	  cups-config
 	  data/testprint
+          data/cups.service
+          data/cups.socket
+          data/cups.path
 	  desktop/cups.desktop
 	  doc/help/ref-cupsd-conf.html
 	  doc/help/standard.html
diff --git a/data/Makefile b/data/Makefile
index b9de21a..cccab85 100644
--- a/data/Makefile
+++ b/data/Makefile
@@ -112,6 +112,12 @@ install-data:
 		$(INSTALL_DATA) $$file $(DATADIR)/ppdc; \
 	done
 	$(INSTALL_DIR) -m 755 $(DATADIR)/profiles
+	if test "x$(SYSTEMD_UNITS)" != "x" ; then \
+		$(INSTALL_DIR) -m 755 $(SYSTEMDUNITDIR); \
+		for file in $(SYSTEMD_UNITS); do \
+			$(INSTALL_DATA) $$file $(SYSTEMDUNITDIR); \
+		done; \
+	fi
 
 
 #
@@ -159,6 +165,9 @@ uninstall:
 	-$(RMDIR) $(DATADIR)/charsets
 	-$(RMDIR) $(DATADIR)/banners
 	-$(RMDIR) $(DATADIR)
+	for file in $(SYSTEMD_UNITS); do \
+		$(RM) $(SYSTEMDUNITDIR)/$$file; \
+	done
 
 
 #
diff --git a/data/cups.path.in b/data/cups.path.in
new file mode 100644
index 0000000..c99e39b
--- /dev/null
+++ b/data/cups.path.in
@@ -0,0 +1,8 @@
+[Unit]
+Description=CUPS Printer Service Spool
+
+[Path]
+DirectoryNotEmpty=@CUPS_REQUESTS@
+
+[Install]
+WantedBy=multi-user.target
diff --git a/data/cups.service.in b/data/cups.service.in
new file mode 100644
index 0000000..007d0e6
--- /dev/null
+++ b/data/cups.service.in
@@ -0,0 +1,9 @@
+[Unit]
+Description=CUPS Printing Service
+
+[Service]
+ExecStart=@sbindir@/cupsd -f
+
+[Install]
+Also=cups.socket cups.path
+WantedBy=printer.target
diff --git a/data/cups.socket.in b/data/cups.socket.in
new file mode 100644
index 0000000..b940096
--- /dev/null
+++ b/data/cups.socket.in
@@ -0,0 +1,9 @@
+[Unit]
+Description=CUPS Printing Service Sockets
+
+[Socket]
+ListenStream=@CUPS_DEFAULT_DOMAINSOCKET@
+ListenStream=631
+
+[Install]
+WantedBy=sockets.target
diff --git a/scheduler/Makefile b/scheduler/Makefile
index 3c7da8e..05152a6 100644
--- a/scheduler/Makefile
+++ b/scheduler/Makefile
@@ -39,6 +39,7 @@ CUPSDOBJS =	\
 		server.o \
 		statbuf.o \
 		subscriptions.o \
+		sd-daemon.o \
 		sysman.o
 LIBOBJS =	\
 		filter.o \
@@ -568,6 +569,14 @@ sloc:
 
 
 #
+# Update sd-daemon.[ch] drop-in file from upstream git
+#
+
+update-systemd:
+	curl http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.c > sd-daemon.c
+	curl http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.h > sd-daemon.h
+
+#
 # Dependencies...
 #
 
diff --git a/scheduler/main.c b/scheduler/main.c
index baaa3a1..5a4b8e1 100644
--- a/scheduler/main.c
+++ b/scheduler/main.c
@@ -26,6 +26,8 @@
  *   launchd_checkin()     - Check-in with launchd and collect the listening
  *                           fds.
  *   launchd_checkout()    - Update the launchd KeepAlive file as needed.
+ *   systemd_checkin()     - Check-in with systemd and collect the
+ *                           listening fds.
  *   parent_handler()      - Catch USR1/CHLD signals...
  *   process_children()    - Process all dead children...
  *   select_timeout()      - Calculate the select timeout value.
@@ -62,6 +64,8 @@
 #  endif /* !LAUNCH_JOBKEY_SERVICEIPC */
 #endif /* HAVE_LAUNCH_H */
 
+#include "sd-daemon.h"
+
 #if defined(HAVE_MALLOC_H) && defined(HAVE_MALLINFO)
 #  include <malloc.h>
 #endif /* HAVE_MALLOC_H && HAVE_MALLINFO */
@@ -78,6 +82,7 @@
 static void		launchd_checkin(void);
 static void		launchd_checkout(void);
 #endif /* HAVE_LAUNCHD */
+static void		systemd_checkin(void);
 static void		parent_handler(int sig);
 static void		process_children(void);
 static void		sigchld_handler(int sig);
@@ -520,6 +525,11 @@ main(int  argc,				/* I - Number of command-line args */
 #endif /* HAVE_LAUNCHD */
 
  /*
+  * If we were started by systemd get the listen sockets file descriptors...
+  */
+  systemd_checkin();
+
+ /*
   * Startup the server...
   */
 
@@ -731,6 +741,12 @@ main(int  argc,				/* I - Number of command-line args */
 #endif /* HAVE_LAUNCHD */
 
        /*
+        * If we were started by systemd get the listen sockets file descriptors...
+        */
+
+        systemd_checkin();
+
+       /*
         * Startup the server...
         */
 
@@ -1535,6 +1551,97 @@ launchd_checkout(void)
 }
 #endif /* HAVE_LAUNCHD */
 
+static void
+systemd_checkin(void)
+{
+  int n, fd;
+
+  n = sd_listen_fds(1);
+  if (n < 0)
+  {
+    cupsdLogMessage(CUPSD_LOG_ERROR,
+           "systemd_checkin: Failed to acquire sockets from systemd - %s",
+           strerror(-n));
+    exit(EXIT_FAILURE);
+    return;
+  }
+
+  if (n == 0)
+    return;
+
+  for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd ++)
+  {
+    http_addr_t addr;
+    socklen_t addrlen;
+    int r;
+    cupsd_listener_t *lis;
+    char s[256];
+
+    r = sd_is_socket(fd, AF_UNSPEC, SOCK_STREAM, 1);
+    if (r < 0) {
+      cupsdLogMessage(CUPSD_LOG_ERROR,
+             "systemd_checkin: Unable to verify socket type - %s",
+             strerror(-r));
+      continue;
+    }
+
+    if (!r) {
+      cupsdLogMessage(CUPSD_LOG_ERROR,
+             "systemd_checkin: Socket not of the right type");
+      continue;
+    }
+
+    if (getsockname(fd, (struct sockaddr*) &addr, &addrlen))
+    {
+      cupsdLogMessage(CUPSD_LOG_ERROR,
+             "systemd_checkin: Unable to get local address - %s",
+             strerror(errno));
+      continue;
+    }
+
+     /*
+    * Try to match the systemd socket address to one of the listeners...
+    */
+
+    for (lis = (cupsd_listener_t *)cupsArrayFirst(Listeners);
+       lis;
+       lis = (cupsd_listener_t *)cupsArrayNext(Listeners))
+      if (httpAddrEqual(&lis->address, &addr))
+      break;
+
+    if (lis)
+    {
+      cupsdLogMessage(CUPSD_LOG_DEBUG,
+                      "systemd_checkin: Matched existing listener %s with fd %d...",
+                      httpAddrString(&(lis->address), s, sizeof(s)), fd);
+    }
+    else
+    {
+      cupsdLogMessage(CUPSD_LOG_DEBUG,
+                      "systemd_checkin: Adding new listener %s with fd %d...",
+                      httpAddrString(&addr, s, sizeof(s)), fd);
+
+      if ((lis = calloc(1, sizeof(cupsd_listener_t))) == NULL)
+      {
+        cupsdLogMessage(CUPSD_LOG_ERROR,
+                        "systemd_checkin: Unable to allocate listener - "
+                        "%s.", strerror(errno));
+        exit(EXIT_FAILURE);
+      }
+
+      cupsArrayAdd(Listeners, lis);
+
+      memcpy(&lis->address, &addr, sizeof(lis->address));
+    }
+
+    lis->fd = fd;
+
+#  ifdef HAVE_SSL
+    if (_httpAddrPort(&(lis->address)) == 443)
+      lis->encryption = HTTP_ENCRYPT_ALWAYS;
+#  endif /* HAVE_SSL */
+  }
+}
 
 /*
  * 'parent_handler()' - Catch USR1/CHLD signals...
diff --git a/scheduler/sd-daemon.c b/scheduler/sd-daemon.c
new file mode 100644
index 0000000..a2ec74c
--- /dev/null
+++ b/scheduler/sd-daemon.c
@@ -0,0 +1,520 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  Copyright 2010 Lennart Poettering
+
+  Permission is hereby granted, free of charge, to any person
+  obtaining a copy of this software and associated documentation files
+  (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge,
+  publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+***/
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/fcntl.h>
+#include <netinet/in.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <limits.h>
+
+#if defined(__linux__)
+#include <mqueue.h>
+#endif
+
+#include "sd-daemon.h"
+
+#if (__GNUC__ >= 4) && !defined(SD_EXPORT_SYMBOLS)
+#define _sd_hidden_ __attribute__ ((visibility("hidden")))
+#else
+#define _sd_hidden_
+#endif
+
+_sd_hidden_ int sd_listen_fds(int unset_environment) {
+
+#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
+        return 0;
+#else
+        int r, fd;
+        const char *e;
+        char *p = NULL;
+        unsigned long l;
+
+        if (!(e = getenv("LISTEN_PID"))) {
+                r = 0;
+                goto finish;
+        }
+
+        errno = 0;
+        l = strtoul(e, &p, 10);
+
+        if (errno != 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        if (!p || *p || l <= 0) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        /* Is this for us? */
+        if (getpid() != (pid_t) l) {
+                r = 0;
+                goto finish;
+        }
+
+        if (!(e = getenv("LISTEN_FDS"))) {
+                r = 0;
+                goto finish;
+        }
+
+        errno = 0;
+        l = strtoul(e, &p, 10);
+
+        if (errno != 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        if (!p || *p) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + (int) l; fd ++) {
+                int flags;
+
+                if ((flags = fcntl(fd, F_GETFD)) < 0) {
+                        r = -errno;
+                        goto finish;
+                }
+
+                if (flags & FD_CLOEXEC)
+                        continue;
+
+                if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0) {
+                        r = -errno;
+                        goto finish;
+                }
+        }
+
+        r = (int) l;
+
+finish:
+        if (unset_environment) {
+                unsetenv("LISTEN_PID");
+                unsetenv("LISTEN_FDS");
+        }
+
+        return r;
+#endif
+}
+
+_sd_hidden_ int sd_is_fifo(int fd, const char *path) {
+        struct stat st_fd;
+
+        if (fd < 0)
+                return -EINVAL;
+
+        memset(&st_fd, 0, sizeof(st_fd));
+        if (fstat(fd, &st_fd) < 0)
+                return -errno;
+
+        if (!S_ISFIFO(st_fd.st_mode))
+                return 0;
+
+        if (path) {
+                struct stat st_path;
+
+                memset(&st_path, 0, sizeof(st_path));
+                if (stat(path, &st_path) < 0) {
+
+                        if (errno == ENOENT || errno == ENOTDIR)
+                                return 0;
+
+                        return -errno;
+                }
+
+                return
+                        st_path.st_dev == st_fd.st_dev &&
+                        st_path.st_ino == st_fd.st_ino;
+        }
+
+        return 1;
+}
+
+_sd_hidden_ int sd_is_special(int fd, const char *path) {
+        struct stat st_fd;
+
+        if (fd < 0)
+                return -EINVAL;
+
+        if (fstat(fd, &st_fd) < 0)
+                return -errno;
+
+        if (!S_ISREG(st_fd.st_mode) && !S_ISCHR(st_fd.st_mode))
+                return 0;
+
+        if (path) {
+                struct stat st_path;
+
+                if (stat(path, &st_path) < 0) {
+
+                        if (errno == ENOENT || errno == ENOTDIR)
+                                return 0;
+
+                        return -errno;
+                }
+
+                if (S_ISREG(st_fd.st_mode) && S_ISREG(st_path.st_mode))
+                        return
+                                st_path.st_dev == st_fd.st_dev &&
+                                st_path.st_ino == st_fd.st_ino;
+                else if (S_ISCHR(st_fd.st_mode) && S_ISCHR(st_path.st_mode))
+                        return st_path.st_rdev == st_fd.st_rdev;
+                else
+                        return 0;
+        }
+
+        return 1;
+}
+
+static int sd_is_socket_internal(int fd, int type, int listening) {
+        struct stat st_fd;
+
+        if (fd < 0 || type < 0)
+                return -EINVAL;
+
+        if (fstat(fd, &st_fd) < 0)
+                return -errno;
+
+        if (!S_ISSOCK(st_fd.st_mode))
+                return 0;
+
+        if (type != 0) {
+                int other_type = 0;
+                socklen_t l = sizeof(other_type);
+
+                if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &other_type, &l) < 0)
+                        return -errno;
+
+                if (l != sizeof(other_type))
+                        return -EINVAL;
+
+                if (other_type != type)
+                        return 0;
+        }
+
+        if (listening >= 0) {
+                int accepting = 0;
+                socklen_t l = sizeof(accepting);
+
+                if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &accepting, &l) < 0)
+                        return -errno;
+
+                if (l != sizeof(accepting))
+                        return -EINVAL;
+
+                if (!accepting != !listening)
+                        return 0;
+        }
+
+        return 1;
+}
+
+union sockaddr_union {
+        struct sockaddr sa;
+        struct sockaddr_in in4;
+        struct sockaddr_in6 in6;
+        struct sockaddr_un un;
+        struct sockaddr_storage storage;
+};
+
+_sd_hidden_ int sd_is_socket(int fd, int family, int type, int listening) {
+        int r;
+
+        if (family < 0)
+                return -EINVAL;
+
+        if ((r = sd_is_socket_internal(fd, type, listening)) <= 0)
+                return r;
+
+        if (family > 0) {
+                union sockaddr_union sockaddr;
+                socklen_t l;
+
+                memset(&sockaddr, 0, sizeof(sockaddr));
+                l = sizeof(sockaddr);
+
+                if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                        return -errno;
+
+                if (l < sizeof(sa_family_t))
+                        return -EINVAL;
+
+                return sockaddr.sa.sa_family == family;
+        }
+
+        return 1;
+}
+
+_sd_hidden_ int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port) {
+        union sockaddr_union sockaddr;
+        socklen_t l;
+        int r;
+
+        if (family != 0 && family != AF_INET && family != AF_INET6)
+                return -EINVAL;
+
+        if ((r = sd_is_socket_internal(fd, type, listening)) <= 0)
+                return r;
+
+        memset(&sockaddr, 0, sizeof(sockaddr));
+        l = sizeof(sockaddr);
+
+        if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                return -errno;
+
+        if (l < sizeof(sa_family_t))
+                return -EINVAL;
+
+        if (sockaddr.sa.sa_family != AF_INET &&
+            sockaddr.sa.sa_family != AF_INET6)
+                return 0;
+
+        if (family > 0)
+                if (sockaddr.sa.sa_family != family)
+                        return 0;
+
+        if (port > 0) {
+                if (sockaddr.sa.sa_family == AF_INET) {
+                        if (l < sizeof(struct sockaddr_in))
+                                return -EINVAL;
+
+                        return htons(port) == sockaddr.in4.sin_port;
+                } else {
+                        if (l < sizeof(struct sockaddr_in6))
+                                return -EINVAL;
+
+                        return htons(port) == sockaddr.in6.sin6_port;
+                }
+        }
+
+        return 1;
+}
+
+_sd_hidden_ int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length) {
+        union sockaddr_union sockaddr;
+        socklen_t l;
+        int r;
+
+        if ((r = sd_is_socket_internal(fd, type, listening)) <= 0)
+                return r;
+
+        memset(&sockaddr, 0, sizeof(sockaddr));
+        l = sizeof(sockaddr);
+
+        if (getsockname(fd, &sockaddr.sa, &l) < 0)
+                return -errno;
+
+        if (l < sizeof(sa_family_t))
+                return -EINVAL;
+
+        if (sockaddr.sa.sa_family != AF_UNIX)
+                return 0;
+
+        if (path) {
+                if (length <= 0)
+                        length = strlen(path);
+
+                if (length <= 0)
+                        /* Unnamed socket */
+                        return l == offsetof(struct sockaddr_un, sun_path);
+
+                if (path[0])
+                        /* Normal path socket */
+                        return
+                                (l >= offsetof(struct sockaddr_un, sun_path) + length + 1) &&
+                                memcmp(path, sockaddr.un.sun_path, length+1) == 0;
+                else
+                        /* Abstract namespace socket */
+                        return
+                                (l == offsetof(struct sockaddr_un, sun_path) + length) &&
+                                memcmp(path, sockaddr.un.sun_path, length) == 0;
+        }
+
+        return 1;
+}
+
+_sd_hidden_ int sd_is_mq(int fd, const char *path) {
+#if !defined(__linux__)
+        return 0;
+#else
+        struct mq_attr attr;
+
+        if (fd < 0)
+                return -EINVAL;
+
+        if (mq_getattr(fd, &attr) < 0)
+                return -errno;
+
+        if (path) {
+                char fpath[PATH_MAX];
+                struct stat a, b;
+
+                if (path[0] != '/')
+                        return -EINVAL;
+
+                if (fstat(fd, &a) < 0)
+                        return -errno;
+
+                strncpy(stpcpy(fpath, "/dev/mqueue"), path, sizeof(fpath) - 12);
+                fpath[sizeof(fpath)-1] = 0;
+
+                if (stat(fpath, &b) < 0)
+                        return -errno;
+
+                if (a.st_dev != b.st_dev ||
+                    a.st_ino != b.st_ino)
+                        return 0;
+        }
+
+        return 1;
+#endif
+}
+
+_sd_hidden_ int sd_notify(int unset_environment, const char *state) {
+#if defined(DISABLE_SYSTEMD) || !defined(__linux__) || !defined(SOCK_CLOEXEC)
+        return 0;
+#else
+        int fd = -1, r;
+        struct msghdr msghdr;
+        struct iovec iovec;
+        union sockaddr_union sockaddr;
+        const char *e;
+
+        if (!state) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        if (!(e = getenv("NOTIFY_SOCKET")))
+                return 0;
+
+        /* Must be an abstract socket, or an absolute path */
+        if ((e[0] != '@' && e[0] != '/') || e[1] == 0) {
+                r = -EINVAL;
+                goto finish;
+        }
+
+        if ((fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0)) < 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        memset(&sockaddr, 0, sizeof(sockaddr));
+        sockaddr.sa.sa_family = AF_UNIX;
+        strncpy(sockaddr.un.sun_path, e, sizeof(sockaddr.un.sun_path));
+
+        if (sockaddr.un.sun_path[0] == '@')
+                sockaddr.un.sun_path[0] = 0;
+
+        memset(&iovec, 0, sizeof(iovec));
+        iovec.iov_base = (char*) state;
+        iovec.iov_len = strlen(state);
+
+        memset(&msghdr, 0, sizeof(msghdr));
+        msghdr.msg_name = &sockaddr;
+        msghdr.msg_namelen = offsetof(struct sockaddr_un, sun_path) + strlen(e);
+
+        if (msghdr.msg_namelen > sizeof(struct sockaddr_un))
+                msghdr.msg_namelen = sizeof(struct sockaddr_un);
+
+        msghdr.msg_iov = &iovec;
+        msghdr.msg_iovlen = 1;
+
+        if (sendmsg(fd, &msghdr, MSG_NOSIGNAL) < 0) {
+                r = -errno;
+                goto finish;
+        }
+
+        r = 1;
+
+finish:
+        if (unset_environment)
+                unsetenv("NOTIFY_SOCKET");
+
+        if (fd >= 0)
+                close(fd);
+
+        return r;
+#endif
+}
+
+_sd_hidden_ int sd_notifyf(int unset_environment, const char *format, ...) {
+#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
+        return 0;
+#else
+        va_list ap;
+        char *p = NULL;
+        int r;
+
+        va_start(ap, format);
+        r = vasprintf(&p, format, ap);
+        va_end(ap);
+
+        if (r < 0 || !p)
+                return -ENOMEM;
+
+        r = sd_notify(unset_environment, p);
+        free(p);
+
+        return r;
+#endif
+}
+
+_sd_hidden_ int sd_booted(void) {
+#if defined(DISABLE_SYSTEMD) || !defined(__linux__)
+        return 0;
+#else
+
+        struct stat a, b;
+
+        /* We simply test whether the systemd cgroup hierarchy is
+         * mounted */
+
+        if (lstat("/sys/fs/cgroup", &a) < 0)
+                return 0;
+
+        if (lstat("/sys/fs/cgroup/systemd", &b) < 0)
+                return 0;
+
+        return a.st_dev != b.st_dev;
+#endif
+}
diff --git a/scheduler/sd-daemon.h b/scheduler/sd-daemon.h
new file mode 100644
index 0000000..46dc7fd
--- /dev/null
+++ b/scheduler/sd-daemon.h
@@ -0,0 +1,277 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef foosddaemonhfoo
+#define foosddaemonhfoo
+
+/***
+  Copyright 2010 Lennart Poettering
+
+  Permission is hereby granted, free of charge, to any person
+  obtaining a copy of this software and associated documentation files
+  (the "Software"), to deal in the Software without restriction,
+  including without limitation the rights to use, copy, modify, merge,
+  publish, distribute, sublicense, and/or sell copies of the Software,
+  and to permit persons to whom the Software is furnished to do so,
+  subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be
+  included in all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+  BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+  ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+***/
+
+#include <sys/types.h>
+#include <inttypes.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+  Reference implementation of a few systemd related interfaces for
+  writing daemons. These interfaces are trivial to implement. To
+  simplify porting we provide this reference implementation.
+  Applications are welcome to reimplement the algorithms described
+  here if they do not want to include these two source files.
+
+  The following functionality is provided:
+
+  - Support for logging with log levels on stderr
+  - File descriptor passing for socket-based activation
+  - Daemon startup and status notification
+  - Detection of systemd boots
+
+  You may compile this with -DDISABLE_SYSTEMD to disable systemd
+  support. This makes all those calls NOPs that are directly related to
+  systemd (i.e. only sd_is_xxx() will stay useful).
+
+  Since this is drop-in code we don't want any of our symbols to be
+  exported in any case. Hence we declare hidden visibility for all of
+  them.
+
+  You may find an up-to-date version of these source files online:
+
+  http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.h
+  http://cgit.freedesktop.org/systemd/plain/src/sd-daemon.c
+
+  This should compile on non-Linux systems, too, but with the
+  exception of the sd_is_xxx() calls all functions will become NOPs.
+
+  See sd-daemon(7) for more information.
+*/
+
+#ifndef _sd_printf_attr_
+#if __GNUC__ >= 4
+#define _sd_printf_attr_(a,b) __attribute__ ((format (printf, a, b)))
+#else
+#define _sd_printf_attr_(a,b)
+#endif
+#endif
+
+/*
+  Log levels for usage on stderr:
+
+          fprintf(stderr, SD_NOTICE "Hello World!\n");
+
+  This is similar to printk() usage in the kernel.
+*/
+#define SD_EMERG   "<0>"  /* system is unusable */
+#define SD_ALERT   "<1>"  /* action must be taken immediately */
+#define SD_CRIT    "<2>"  /* critical conditions */
+#define SD_ERR     "<3>"  /* error conditions */
+#define SD_WARNING "<4>"  /* warning conditions */
+#define SD_NOTICE  "<5>"  /* normal but significant condition */
+#define SD_INFO    "<6>"  /* informational */
+#define SD_DEBUG   "<7>"  /* debug-level messages */
+
+/* The first passed file descriptor is fd 3 */
+#define SD_LISTEN_FDS_START 3
+
+/*
+  Returns how many file descriptors have been passed, or a negative
+  errno code on failure. Optionally, removes the $LISTEN_FDS and
+  $LISTEN_PID file descriptors from the environment (recommended, but
+  problematic in threaded environments). If r is the return value of
+  this function you'll find the file descriptors passed as fds
+  SD_LISTEN_FDS_START to SD_LISTEN_FDS_START+r-1. Returns a negative
+  errno style error code on failure. This function call ensures that
+  the FD_CLOEXEC flag is set for the passed file descriptors, to make
+  sure they are not passed on to child processes. If FD_CLOEXEC shall
+  not be set, the caller needs to unset it after this call for all file
+  descriptors that are used.
+
+  See sd_listen_fds(3) for more information.
+*/
+int sd_listen_fds(int unset_environment);
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is a FIFO in the file system stored under the
+  specified path, 0 otherwise. If path is NULL a path name check will
+  not be done and the call only verifies if the file descriptor
+  refers to a FIFO. Returns a negative errno style error code on
+  failure.
+
+  See sd_is_fifo(3) for more information.
+*/
+int sd_is_fifo(int fd, const char *path);
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is a special character device on the file
+  system stored under the specified path, 0 otherwise.
+  If path is NULL a path name check will not be done and the call
+  only verifies if the file descriptor refers to a special character.
+  Returns a negative errno style error code on failure.
+
+  See sd_is_special(3) for more information.
+*/
+int sd_is_special(int fd, const char *path);
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is a socket of the specified family (AF_INET,
+  ...) and type (SOCK_DGRAM, SOCK_STREAM, ...), 0 otherwise. If
+  family is 0 a socket family check will not be done. If type is 0 a
+  socket type check will not be done and the call only verifies if
+  the file descriptor refers to a socket. If listening is > 0 it is
+  verified that the socket is in listening mode. (i.e. listen() has
+  been called) If listening is == 0 it is verified that the socket is
+  not in listening mode. If listening is < 0 no listening mode check
+  is done. Returns a negative errno style error code on failure.
+
+  See sd_is_socket(3) for more information.
+*/
+int sd_is_socket(int fd, int family, int type, int listening);
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is an Internet socket, of the specified family
+  (either AF_INET or AF_INET6) and the specified type (SOCK_DGRAM,
+  SOCK_STREAM, ...), 0 otherwise. If version is 0 a protocol version
+  check is not done. If type is 0 a socket type check will not be
+  done. If port is 0 a socket port check will not be done. The
+  listening flag is used the same way as in sd_is_socket(). Returns a
+  negative errno style error code on failure.
+
+  See sd_is_socket_inet(3) for more information.
+*/
+int sd_is_socket_inet(int fd, int family, int type, int listening, uint16_t port);
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is an AF_UNIX socket of the specified type
+  (SOCK_DGRAM, SOCK_STREAM, ...) and path, 0 otherwise. If type is 0
+  a socket type check will not be done. If path is NULL a socket path
+  check will not be done. For normal AF_UNIX sockets set length to
+  0. For abstract namespace sockets set length to the length of the
+  socket name (including the initial 0 byte), and pass the full
+  socket path in path (including the initial 0 byte). The listening
+  flag is used the same way as in sd_is_socket(). Returns a negative
+  errno style error code on failure.
+
+  See sd_is_socket_unix(3) for more information.
+*/
+int sd_is_socket_unix(int fd, int type, int listening, const char *path, size_t length);
+
+/*
+  Helper call for identifying a passed file descriptor. Returns 1 if
+  the file descriptor is a POSIX Message Queue of the specified name,
+  0 otherwise. If path is NULL a message queue name check is not
+  done. Returns a negative errno style error code on failure.
+*/
+int sd_is_mq(int fd, const char *path);
+
+/*
+  Informs systemd about changed daemon state. This takes a number of
+  newline separated environment-style variable assignments in a
+  string. The following variables are known:
+
+     READY=1      Tells systemd that daemon startup is finished (only
+                  relevant for services of Type=notify). The passed
+                  argument is a boolean "1" or "0". Since there is
+                  little value in signaling non-readiness the only
+                  value daemons should send is "READY=1".
+
+     STATUS=...   Passes a single-line status string back to systemd
+                  that describes the daemon state. This is free-from
+                  and can be used for various purposes: general state
+                  feedback, fsck-like programs could pass completion
+                  percentages and failing programs could pass a human
+                  readable error message. Example: "STATUS=Completed
+                  66% of file system check..."
+
+     ERRNO=...    If a daemon fails, the errno-style error code,
+                  formatted as string. Example: "ERRNO=2" for ENOENT.
+
+     BUSERROR=... If a daemon fails, the D-Bus error-style error
+                  code. Example: "BUSERROR=org.freedesktop.DBus.Error.TimedOut"
+
+     MAINPID=...  The main pid of a daemon, in case systemd did not
+                  fork off the process itself. Example: "MAINPID=4711"
+
+  Daemons can choose to send additional variables. However, it is
+  recommended to prefix variable names not listed above with X_.
+
+  Returns a negative errno-style error code on failure. Returns > 0
+  if systemd could be notified, 0 if it couldn't possibly because
+  systemd is not running.
+
+  Example: When a daemon finished starting up, it could issue this
+  call to notify systemd about it:
+
+     sd_notify(0, "READY=1");
+
+  See sd_notifyf() for more complete examples.
+
+  See sd_notify(3) for more information.
+*/
+int sd_notify(int unset_environment, const char *state);
+
+/*
+  Similar to sd_notify() but takes a format string.
+
+  Example 1: A daemon could send the following after initialization:
+
+     sd_notifyf(0, "READY=1\n"
+                   "STATUS=Processing requests...\n"
+                   "MAINPID=%lu",
+                   (unsigned long) getpid());
+
+  Example 2: A daemon could send the following shortly before
+  exiting, on failure:
+
+     sd_notifyf(0, "STATUS=Failed to start up: %s\n"
+                   "ERRNO=%i",
+                   strerror(errno),
+                   errno);
+
+  See sd_notifyf(3) for more information.
+*/
+int sd_notifyf(int unset_environment, const char *format, ...) _sd_printf_attr_(2,3);
+
+/*
+  Returns > 0 if the system was booted with systemd. Returns < 0 on
+  error. Returns 0 if the system was not booted with systemd. Note
+  that all of the functions above handle non-systemd boots just
+  fine. You should NOT protect them with a call to this function. Also
+  note that this function checks whether the system, not the user
+  session is controlled by systemd. However the functions above work
+  for both user and system services.
+
+  See sd_booted(3) for more information.
+*/
+int sd_booted(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
-- 
1.7.6
