binfmt: add binfmt tool to set up binfmt_misc at boot

.gitignore

@@ -1,3 +1,4 @@
+systemd-binfmt
 systemd-getty-generator
 systemd-nspawn
 systemd-stdio-bridge

Makefile.am

@@ -144,7 +144,8 @@ rootlibexec_PROGRAMS = \
 	systemd-timestamp \
 	systemd-ac-power \
 	systemd-detect-virt \
-	systemd-sysctl
+	systemd-sysctl \
+        systemd-binfmt
 
 systemgenerator_PROGRAMS = \
 	systemd-getty-generator
@@ -300,6 +301,7 @@ nodist_systemunit_DATA = \
 	units/systemd-ask-password-wall.service \
 	units/systemd-ask-password-console.service \
 	units/systemd-sysctl.service \
+	units/systemd-binfmt.service \
 	units/halt.service \
 	units/poweroff.service \
 	units/reboot.service \
@@ -343,6 +345,7 @@ EXTRA_DIST = \
 	units/systemd-ask-password-wall.service.in \
 	units/systemd-ask-password-console.service.in \
 	units/systemd-sysctl.service.in \
+	units/systemd-binfmt.service.in \
 	units/halt.service.in \
 	units/poweroff.service.in \
 	units/reboot.service.in \
@@ -569,7 +572,8 @@ MANPAGES = \
 	man/vconsole.conf.5 \
 	man/locale.conf.5 \
 	man/os-release.5 \
-	man/modules-load.d.5
+	man/modules-load.d.5 \
+        man/binfmt.d.5
 
 MANPAGES_ALIAS = \
 	man/reboot.8 \
@@ -799,6 +803,15 @@ systemd_sysctl_CFLAGS = \
 systemd_sysctl_LDADD = \
 	libsystemd-basic.la
 
+systemd_binfmt_SOURCES = \
+	src/binfmt.c
+
+systemd_binfmt_CFLAGS = \
+	$(AM_CFLAGS)
+
+systemd_binfmt_LDADD = \
+	libsystemd-basic.la
+
 systemd_fsck_SOURCES = \
 	src/fsck.c \
 	src/dbus-common.c
@@ -1240,9 +1253,10 @@ CLEANFILES += \
 
 install-data-hook:
 	$(MKDIR_P) -m 0755 \
-		$(DESTDIR)$(sysconfdir)/modules-load.d \
 		$(DESTDIR)$(tmpfilesdir) \
+		$(DESTDIR)$(sysconfdir)/modules-load.d \
 		$(DESTDIR)$(sysconfdir)/sysctl.d \
+		$(DESTDIR)$(sysconfdir)/binfmt.d \
 		$(DESTDIR)$(systemshutdowndir) \
 		$(DESTDIR)$(systemgeneratordir) \
 		$(DESTDIR)$(usergeneratordir)
@@ -1364,6 +1378,7 @@ install-data-hook:
 			systemd-random-seed-load.service \
 			systemd-tmpfiles-setup.service \
 			systemd-sysctl.service \
+			systemd-binfmt.service \
 			systemd-ask-password-console.path \
 			systemd-kmsg-syslogd.service \
 			cryptsetup.target && \
@@ -1377,6 +1392,7 @@ install-data-hook:
 		$(LN_S) ../systemd-random-seed-load.service systemd-random-seed-load.service && \
 		$(LN_S) ../systemd-tmpfiles-setup.service systemd-tmpfiles-setup.service && \
 		$(LN_S) ../systemd-sysctl.service systemd-sysctl.service && \
+		$(LN_S) ../systemd-binfmt.service systemd-binfmt.service && \
 		$(LN_S) ../systemd-ask-password-console.path systemd-ask-password-console.path && \
 		$(LN_S) ../systemd-kmsg-syslogd.service && \
 		$(LN_S) ../cryptsetup.target cryptsetup.target )

man/binfmt.d.xml

@@ -0,0 +1,103 @@
+<?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 2010 Brandon Philips
+
+  systemd 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 2 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+-->
+<refentry id="binfmt.d">
+
+        <refentryinfo>
+                <title>binfmt.d</title>
+                <productname>systemd</productname>
+
+                <authorgroup>
+                        <author>
+                                <contrib>Developer</contrib>
+                                <firstname>Lennart</firstname>
+                                <surname>Poettering</surname>
+                                <email>lennart@poettering.net</email>
+                        </author>
+                </authorgroup>
+        </refentryinfo>
+
+        <refmeta>
+                <refentrytitle>binfmt.d</refentrytitle>
+                <manvolnum>5</manvolnum>
+        </refmeta>
+
+        <refnamediv>
+                <refname>binfmt.d</refname>
+                <refpurpose>Configure additional binary formats at boot</refpurpose>
+        </refnamediv>
+
+        <refsynopsisdiv>
+                <para><filename>/etc/binfmt.d/*.conf</filename></para>
+        </refsynopsisdiv>
+
+        <refsect1>
+                <title>Description</title>
+
+		<para><command>systemd</command> uses
+		<filename>/etc/binfmt.d/</filename> to configure
+		additional binary formats to register during boot in
+		the kernel.  Each configuration file is named in the
+		style of
+		<filename>/etc/binfmt.d/&lt;program&gt;.conf</filename>.</para>
+
+
+        </refsect1>
+
+        <refsect1>
+		<title>Configuration Format</title>
+
+                <para>Each file contains a list of binfmt_misc kernel
+                binary format rules. Consult <ulink
+                url="http://www.kernel.org/doc/Documentation/binfmt_misc.txt">binfmt_misc.txt</ulink>
+                for more information on registration of additional
+                binary formats and how to write rules.</para>
+
+                <para>Empty lines and lines beginning with ; and # are
+                ignored. Note that this means you may not use ; and #
+                as delimiter in binary format rules.</para>
+
+                <para>Configuration files are loaded in alphabetical
+                order. To ensure that a specific rule takes precedence
+                over another place it in a file with an alphabetically
+                later name.</para>
+
+        </refsect1>
+
+        <refsect1>
+                <title>Example</title>
+                <example>
+                        <title>/etc/binfmt.d/wine.conf example:</title>
+
+                        <programlisting># Start WINE on Windows executables
+:DOSWin:M::MZ::/usr/bin/wine:</programlisting>
+                </example>
+        </refsect1>
+
+        <refsect1>
+                <title>See Also</title>
+                <para>
+                        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>wine</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                </para>
+        </refsect1>
+
+</refentry>

src/binfmt.c

@@ -0,0 +1,187 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd 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 2 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <limits.h>
+
+#include "log.h"
+#include "util.h"
+
+static int delete_rule(const char *rule) {
+        char *x, *fn, *e;
+        int r;
+
+        assert(rule[0]);
+
+        if (!(x = strdup(rule)))
+                return -ENOMEM;
+
+        e = strchrnul(x+1, x[0]);
+        *e = 0;
+
+        asprintf(&fn, "/proc/sys/fs/binfmt_misc/%s", x+1);
+        free(x);
+
+        if (!fn)
+                return -ENOMEM;
+
+        r = write_one_line_file(fn, "-1");
+        free(fn);
+
+        return r;
+}
+
+static int apply_rule(const char *rule) {
+        int r;
+
+        delete_rule(rule);
+
+        if ((r = write_one_line_file("/proc/sys/fs/binfmt_misc/register", rule)) < 0) {
+                log_error("Failed to add binary format: %s", strerror(-r));
+                return r;
+        }
+
+        return 0;
+}
+
+static int apply_file(const char *path, bool ignore_enoent) {
+        FILE *f;
+        int r = 0;
+
+        assert(path);
+
+        if (!(f = fopen(path, "re"))) {
+                if (ignore_enoent && errno == ENOENT)
+                        return 0;
+
+                log_error("Failed to open file '%s', ignoring: %m", path);
+                return -errno;
+        }
+
+        while (!feof(f)) {
+                char l[LINE_MAX], *p;
+                int k;
+
+                if (!fgets(l, sizeof(l), f)) {
+                        if (feof(f))
+                                break;
+
+                        log_error("Failed to read file '%s', ignoring: %m", path);
+                        r = -errno;
+                        goto finish;
+                }
+
+                p = strstrip(l);
+
+                if (!*p)
+                        continue;
+
+                if (strchr(COMMENTS, *p))
+                        continue;
+
+                if ((k = apply_rule(p)) < 0 && r == 0)
+                        r = k;
+        }
+
+finish:
+        fclose(f);
+
+        return r;
+}
+
+static int scandir_filter(const struct dirent *d) {
+        assert(d);
+
+        if (ignore_file(d->d_name))
+                return 0;
+
+        if (d->d_type != DT_REG &&
+            d->d_type != DT_LNK &&
+            d->d_type != DT_UNKNOWN)
+                return 0;
+
+        return endswith(d->d_name, ".conf");
+}
+
+static int apply_tree(const char *path) {
+        struct dirent **de = NULL;
+        int n, i, r = 0;
+
+        if ((n = scandir(path, &de, scandir_filter, alphasort)) < 0) {
+
+                if (errno == ENOENT)
+                        return 0;
+
+                log_error("Failed to enumerate %s files: %m", path);
+                return -errno;
+        }
+
+        for (i = 0; i < n; i++) {
+                char *fn;
+                int k;
+
+                k = asprintf(&fn, "%s/%s", path, de[i]->d_name);
+                free(de[i]);
+
+                if (k < 0) {
+                        log_error("Failed to allocate file name.");
+
+                        if (r == 0)
+                                r = -ENOMEM;
+                        continue;
+                }
+
+                if ((k = apply_file(fn, true)) < 0 && r == 0)
+                        r = k;
+        }
+
+        free(de);
+
+        return r;
+}
+
+int main(int argc, char *argv[]) {
+        int r = 0;
+
+        if (argc > 2) {
+                log_error("This program expects one or no arguments.");
+                return EXIT_FAILURE;
+        }
+
+        log_set_target(LOG_TARGET_AUTO);
+        log_parse_environment();
+        log_open();
+
+        if (argc > 1)
+                r = apply_file(argv[1], false);
+        else {
+                /* Flush out all rules */
+                write_one_line_file("/proc/sys/fs/binfmt_misc/status", "-1");
+
+                r = apply_tree("/etc/binfmt.d");
+        }
+
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}

src/util.c

@@ -513,7 +513,16 @@ int write_one_line_file(const char *fn, const char *line) {
         if (!endswith(line, "\n"))
                 fputc('\n', f);
 
-        r = 0;
+        fflush(f);
+
+        if (ferror(f)) {
+                if (errno != 0)
+                        r = -errno;
+                else
+                        r = -EIO;
+        } else
+                r = 0;
+
 finish:
         fclose(f);
         return r;

units/.gitignore

@@ -34,3 +34,4 @@ remote-fs.target
 systemd-update-utmp-runlevel.service
 systemd-update-utmp-shutdown.service
 test-env-replace
+systemd-binfmt.service

units/systemd-binfmt.service.in

@@ -0,0 +1,19 @@
+#  This file is part of systemd.
+#
+#  systemd 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 2 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Set Up Additional Binary Formats
+DefaultDependencies=no
+Conflicts=shutdown.target
+After=systemd-readahead-collect.service systemd-readahead-replay.service proc-sys-fs-binfmt_misc.automount
+Before=sysinit.target shutdown.target
+ConditionDirectoryNotEmpty=/etc/binfmt.d
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=@rootlibexecdir@/systemd-binfmt