hibernate-resume: add a tool to write a device node's major:minor to /sys/power/resume.

This can be used to initiate a resume from hibernation by path to a swap
device containing the hibernation image.

The respective templated unit is also added. It is instantiated using
path to the desired resume device.

8 files changed, 206 insertions, 3 deletions

diff --git a/.gitignore b/.gitignore
index 8189da71f0..0b5608ccf9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -75,6 +75,7 @@
 /systemd-getty-generator
 /systemd-gnome-ask-password-agent
 /systemd-gpt-auto-generator
+/systemd-hibernate-resume
 /systemd-hostnamed
 /systemd-inhibit
 /systemd-initctl
diff --git a/Makefile-man.am b/Makefile-man.am
index 562ecba435..09a10383a9 100644
--- a/Makefile-man.am
+++ b/Makefile-man.am
@@ -70,6 +70,7 @@ MANPAGES += \
 	man/systemd-getty-generator.8 \
 	man/systemd-gpt-auto-generator.8 \
 	man/systemd-halt.service.8 \
+	man/systemd-hibernate-resume@.service.8 \
 	man/systemd-inhibit.1 \
 	man/systemd-initctl.service.8 \
 	man/systemd-journald.service.8 \
@@ -199,6 +200,7 @@ MANPAGES_ALIAS += \
 	man/systemd-firstboot.service.1 \
 	man/systemd-fsck-root.service.8 \
 	man/systemd-fsck.8 \
+	man/systemd-hibernate-resume.8 \
 	man/systemd-hibernate.service.8 \
 	man/systemd-hybrid-sleep.service.8 \
 	man/systemd-initctl.8 \
@@ -305,6 +307,7 @@ man/systemd-ask-password-wall.service.8: man/systemd-ask-password-console.servic
 man/systemd-firstboot.service.1: man/systemd-firstboot.1
 man/systemd-fsck-root.service.8: man/systemd-fsck@.service.8
 man/systemd-fsck.8: man/systemd-fsck@.service.8
+man/systemd-hibernate-resume.8: man/systemd-hibernate-resume@.service.8
 man/systemd-hibernate.service.8: man/systemd-suspend.service.8
 man/systemd-hybrid-sleep.service.8: man/systemd-suspend.service.8
 man/systemd-initctl.8: man/systemd-initctl.service.8
@@ -567,6 +570,9 @@ man/systemd-fsck-root.service.html: man/systemd-fsck@.service.html
 man/systemd-fsck.html: man/systemd-fsck@.service.html
 	$(html-alias)
 
+man/systemd-hibernate-resume.html: man/systemd-hibernate-resume@.service.html
+	$(html-alias)
+
 man/systemd-hibernate.service.html: man/systemd-suspend.service.html
 	$(html-alias)
 
@@ -1619,6 +1625,7 @@ EXTRA_DIST += \
 	man/systemd-getty-generator.xml \
 	man/systemd-gpt-auto-generator.xml \
 	man/systemd-halt.service.xml \
+	man/systemd-hibernate-resume@.service.xml \
 	man/systemd-hostnamed.service.xml \
 	man/systemd-inhibit.xml \
 	man/systemd-initctl.service.xml \
diff --git a/Makefile.am b/Makefile.am
index cbf98bdac3..a487caa7bc 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -378,7 +378,8 @@ rootlibexec_PROGRAMS = \
 	systemd-sleep \
 	systemd-bus-proxyd \
 	systemd-socket-proxyd \
-	systemd-update-done
+	systemd-update-done \
+	systemd-hibernate-resume
 
 systemgenerator_PROGRAMS = \
 	systemd-getty-generator \
@@ -528,7 +529,8 @@ nodist_systemunit_DATA = \
 	units/initrd-udevadm-cleanup-db.service \
 	units/initrd-switch-root.service \
 	units/systemd-nspawn@.service \
-	units/systemd-update-done.service
+	units/systemd-update-done.service \
+	units/systemd-hibernate-resume@.service
 
 dist_userunit_DATA = \
 	units/user/basic.target \
@@ -575,7 +577,8 @@ EXTRA_DIST += \
 	units/initrd-udevadm-cleanup-db.service.in \
 	units/initrd-switch-root.service.in \
 	units/systemd-nspawn@.service.in \
-	units/systemd-update-done.service.in
+	units/systemd-update-done.service.in \
+	units/systemd-hibernate-resume@.service.in
 
 CLEANFILES += \
 	units/console-shell.service.m4 \
@@ -2103,6 +2106,14 @@ systemd_delta_LDADD = \
 	libsystemd-shared.la
 
 # ------------------------------------------------------------------------------
+systemd_hibernate_resume_SOURCES = \
+	src/hibernate-resume/hibernate-resume.c
+
+systemd_hibernate_resume_LDADD = \
+	libsystemd-internal.la \
+	libsystemd-shared.la
+
+# ------------------------------------------------------------------------------
 systemd_getty_generator_SOURCES = \
 	src/getty-generator/getty-generator.c
 
diff --git a/man/systemd-hibernate-resume@.service.xml b/man/systemd-hibernate-resume@.service.xml
new file mode 100644
index 0000000000..9b188b0d96
--- /dev/null
+++ b/man/systemd-hibernate-resume@.service.xml
@@ -0,0 +1,81 @@
+<?xml version="1.0"?>
+<!--*-nxml-*-->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!--
+  This file is part of systemd.
+
+  Copyright 2014 Ivan Shapovalov
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+-->
+<refentry id="systemd-hibernate-resume@.service">
+
+        <refentryinfo>
+                <title>systemd-hibernate-resume@.service</title>
+                <productname>systemd</productname>
+
+                <authorgroup>
+                        <author>
+                                <contrib>Developer</contrib>
+                                <firstname>Ivan</firstname>
+                                <surname>Shapovalov</surname>
+                                <email>intelfx100@gmail.com</email>
+                        </author>
+                </authorgroup>
+        </refentryinfo>
+
+        <refmeta>
+                <refentrytitle>systemd-hibernate-resume@.service</refentrytitle>
+                <manvolnum>8</manvolnum>
+        </refmeta>
+
+        <refnamediv>
+                <refname>systemd-hibernate-resume@.service</refname>
+                <refname>systemd-hibernate-resume</refname>
+                <refpurpose>Resume from hibernation</refpurpose>
+        </refnamediv>
+
+        <refsynopsisdiv>
+                <para><filename>systemd-hibernate-resume@.service</filename></para>
+                <para><filename>/usr/lib/systemd/systemd-hibernate-resume</filename></para>
+        </refsynopsisdiv>
+
+        <refsect1>
+                <title>Description</title>
+
+                <para><filename>systemd-hibernate-resume@.service</filename> is a
+                service that initiates hibernation resume from a device
+                containing the resume image. It is instantiated for each
+                device that is configured for resuming from.</para>
+
+                <para><filename>systemd-hibernate-resume</filename> only supports
+                the in-kernel hibernation implementation, known as swsusp.
+                Internally, it works by writing the major:minor of specified
+                device node to <filename>/sys/power/resume</filename>.</para>
+
+                <para>Failing to initiate a resume is not an error condition.
+                It may mean that there was no resume image (e. g. if the
+                system has been simply powered off and not hibernated). In
+                such case, the boot is ordinarily continued.</para>
+        </refsect1>
+
+        <refsect1>
+                <title>See Also</title>
+                <para>
+                        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>systemd-hibernate-resume-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                </para>
+        </refsect1>
+
+</refentry>
diff --git a/src/hibernate-resume/Makefile b/src/hibernate-resume/Makefile
new file mode 120000
index 0000000000..d0b0e8e008
--- /dev/null
+++ b/src/hibernate-resume/Makefile
@@ -0,0 +1 @@
+../Makefile
\ No newline at end of file
diff --git a/src/hibernate-resume/hibernate-resume.c b/src/hibernate-resume/hibernate-resume.c
new file mode 100644
index 0000000000..8f68f81f9e
--- /dev/null
+++ b/src/hibernate-resume/hibernate-resume.c
@@ -0,0 +1,81 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 Ivan Shapovalov
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdio.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "log.h"
+#include "util.h"
+#include "fileio.h"
+
+int main(int argc, char *argv[]) {
+        struct stat st;
+        const char *device;
+        _cleanup_free_ char *major_minor = NULL;
+        int r;
+
+        if (argc != 2) {
+                log_error("This program expects one argument.");
+                return EXIT_FAILURE;
+        }
+
+        log_set_target(LOG_TARGET_AUTO);
+        log_parse_environment();
+        log_open();
+
+        umask(0022);
+
+        device = argv[1];
+
+        if (stat(device, &st) < 0) {
+                log_error("Failed to stat '%s': %m", device);
+                return EXIT_FAILURE;
+        }
+
+        if (!S_ISBLK(st.st_mode)) {
+                log_error("Resume device '%s' is not a block device.", device);
+                return EXIT_FAILURE;
+        }
+
+        if (asprintf(&major_minor, "%d:%d", major(st.st_rdev), minor(st.st_rdev)) < 0) {
+                log_oom();
+                return EXIT_FAILURE;
+        }
+
+        r = write_string_file("/sys/power/resume", major_minor);
+        if (r < 0) {
+                log_error("Failed to write '%s' to /sys/power/resume: %s", major_minor, strerror(-r));
+                return EXIT_FAILURE;
+        }
+
+        /*
+         * The write above shall not return.
+         *
+         * However, failed resume is a normal condition (may mean that there is
+         * no hibernation image).
+         */
+
+        log_info("Could not resume from '%s' (%s).", device, major_minor);
+        return EXIT_SUCCESS;
+}
diff --git a/units/.gitignore b/units/.gitignore
index d9b60ac0fc..c60f357416 100644
--- a/units/.gitignore
+++ b/units/.gitignore
@@ -54,6 +54,7 @@
 /systemd-reboot.service
 /systemd-remount-fs.service
 /systemd-resolved.service
+/systemd-hibernate-resume@.service
 /systemd-rfkill@.service
 /systemd-shutdownd.service
 /systemd-suspend.service
diff --git a/units/systemd-hibernate-resume@.service.in b/units/systemd-hibernate-resume@.service.in
new file mode 100644
index 0000000000..6db584dc4d
--- /dev/null
+++ b/units/systemd-hibernate-resume@.service.in
@@ -0,0 +1,20 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Resume from hibernation using device %f
+Documentation=man:systemd-hibernate-resume@.service(8)
+DefaultDependencies=no
+BindsTo=%i.device
+Wants=local-fs-pre.target
+After=%i.device
+Before=local-fs-pre.target systemd-remount-fs.service systemd-fsck-root.service
+ConditionPathExists=/etc/initrd-release
+
+[Service]
+Type=oneshot
+ExecStart=@rootlibexecdir@/systemd-hibernate-resume %f