From 99c06d718c91c91d0992869777c15b457f95443a Mon Sep 17 00:00:00 2001

From: Greg KH <gregkh@linuxfoundation.org>

Date: Fri, 14 Mar 2014 04:43:04 +0000

Subject: [PATCH] machine-id: add --root option to operate on an alternate fs

 tree

This makes it possible to initialize the /etc/machine-id file on an

arbitrary filesystem hierarchy.  This helps systems that wish to run

this at image creation time in a subdirectory, or from initramfs before

pivot-root is called.

[tomegun: converted to using _cleanup_free_ macros]

Conflicts:

	man/systemd-machine-id-setup.xml

	src/machine-id-setup/machine-id-setup-main.c

(cherry picked from commit 92f2f92edcad46ce4098ee26504edca0a1dad68e)

Related: #1111199

---

 man/systemd-machine-id-setup.xml             | 23 +++++++--------

 src/core/machine-id-setup.c                  | 44 ++++++++++++++++++----------

 src/core/machine-id-setup.h                  |  2 +-

 src/core/main.c                              |  2 +-

 src/machine-id-setup/machine-id-setup-main.c | 17 ++++++++---

 5 files changed, 53 insertions(+), 35 deletions(-)

diff --git a/man/systemd-machine-id-setup.xml b/man/systemd-machine-id-setup.xml

index 7b3aa7e..b879b40 100644

--- a/man/systemd-machine-id-setup.xml

+++ b/man/systemd-machine-id-setup.xml

@@ -21,7 +21,8 @@

   along with systemd; If not, see <http://www.gnu.org/licenses/>.

 -->

-<refentry id="systemd-machine-id-setup">

+

+          xmlns:xi="http://www.w3.org/2001/XInclude">

         <refentryinfo>

                 <title>systemd-machine-id-setup</title>

@@ -96,19 +97,15 @@

                 <variablelist>

                         <varlistentry>

-                                <term><option>-h</option></term>

-                                <term><option>--help</option></term>

-

-                                <listitem><para>Prints a short help

-                                text and exits.</para></listitem>

-                        </varlistentry>

-

-                        <varlistentry>

-                                <term><option>--version</option></term>

-

-                                <listitem><para>Prints a short version

-                                string and exits.</para></listitem>

+                                <term><option>--root=ROOT</option></term>

+                                <listitem><para>Takes a directory path

+                                as an argument. All paths will be

+                                prefixed with the given alternate ROOT

+                                path, including config search paths.

+                                </para></listitem>

                         </varlistentry>

+                        <xi:include href="standard-options.xml" xpointer="help" />

+                        <xi:include href="standard-options.xml" xpointer="version" />

                 </variablelist>

         </refsect1>

diff --git a/src/core/machine-id-setup.c b/src/core/machine-id-setup.c

index 18e015f..291930e 100644

--- a/src/core/machine-id-setup.c

+++ b/src/core/machine-id-setup.c

@@ -59,18 +59,22 @@ static int shorten_uuid(char destination[36], const char *source) {

         return -EINVAL;

 }

-static int generate(char id[34]) {

+static int generate(char id[34], const char *root) {

         int fd, r;

         unsigned char *p;

         sd_id128_t buf;

         char *q;

         ssize_t k;

         const char *vm_id;

+        _cleanup_free_ char *dbus_machine_id = NULL;

         assert(id);

+        if (asprintf(&dbus_machine_id, "%s/var/lib/dbus/machine-id", root) < 0)

+                return log_oom();

+

         /* First, try reading the D-Bus machine id, unless it is a symlink */

-        fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);

+        fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);

         if (fd >= 0) {

                 k = loop_read(fd, id, 33, false);

                 close_nointr_nofail(fd);

@@ -150,12 +154,20 @@ static int generate(char id[34]) {

         return 0;

 }

-int machine_id_setup(void) {

+int machine_id_setup(const char *root) {

         _cleanup_close_ int fd = -1;

         int r;

         bool writable;

         struct stat st;

         char id[34]; /* 32 + \n + \0 */

+        _cleanup_free_ char *etc_machine_id = NULL;

+        _cleanup_free_ char *run_machine_id = NULL;

+

+        if (asprintf(&etc_machine_id, "%s/etc/machine-id", root) < 0)

+                return log_oom();

+

+        if (asprintf(&run_machine_id, "%s/run/machine-id", root) < 0)

+                return log_oom();

         RUN_WITH_UMASK(0000) {

                 /* We create this 0444, to indicate that this isn't really

@@ -163,13 +175,13 @@ int machine_id_setup(void) {

                  * will be owned by root it doesn't matter much, but maybe

                  * people look. */

-                fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);

+                fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);

                 if (fd >= 0)

                         writable = true;

                 else {

-                        fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);

+                        fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY);

                         if (fd < 0) {

-                                log_error("Cannot open /etc/machine-id: %m");

+                                log_error("Cannot open %s: %m", etc_machine_id);

                                 return -errno;

                         }

@@ -193,7 +205,7 @@ int machine_id_setup(void) {

         /* Hmm, so, the id currently stored is not useful, then let's

          * generate one */

-        r = generate(id);

+        r = generate(id, root);

         if (r < 0)

                 return r;

@@ -211,27 +223,27 @@ int machine_id_setup(void) {

          * /run/machine-id as a replacement */

         RUN_WITH_UMASK(0022) {

-                r = write_string_file("/run/machine-id", id);

+                r = write_string_file(run_machine_id, id);

         }

         if (r < 0) {

-                log_error("Cannot write /run/machine-id: %s", strerror(-r));

-                unlink("/run/machine-id");

+                log_error("Cannot write %s: %s", run_machine_id, strerror(-r));

+                unlink(run_machine_id);

                 return r;

         }

         /* And now, let's mount it over */

-        r = mount("/run/machine-id", "/etc/machine-id", NULL, MS_BIND, NULL);

+        r = mount(run_machine_id, etc_machine_id, NULL, MS_BIND, NULL);

         if (r < 0) {

-                log_error("Failed to mount /etc/machine-id: %m");

-                unlink_noerrno("/run/machine-id");

+                log_error("Failed to mount %s: %m", etc_machine_id);

+                unlink_noerrno(run_machine_id);

                 return -errno;

         }

-        log_info("Installed transient /etc/machine-id file.");

+        log_info("Installed transient %s file.", etc_machine_id);

         /* Mark the mount read-only */

-        if (mount(NULL, "/etc/machine-id", NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL) < 0)

-                log_warning("Failed to make transient /etc/machine-id read-only: %m");

+        if (mount(NULL, etc_machine_id, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL) < 0)

+                log_warning("Failed to make transient %s read-only: %m", etc_machine_id);

         return 0;

 }

diff --git a/src/core/machine-id-setup.h b/src/core/machine-id-setup.h

index b9e6b4d..b0583ee 100644

--- a/src/core/machine-id-setup.h

+++ b/src/core/machine-id-setup.h

@@ -21,4 +21,4 @@

   along with systemd; If not, see <http://www.gnu.org/licenses/>.

 ***/

-int machine_id_setup(void);

+int machine_id_setup(const char *root);

diff --git a/src/core/main.c b/src/core/main.c

index 00fd394..afd5f6f 100644

--- a/src/core/main.c

+++ b/src/core/main.c

@@ -1503,7 +1503,7 @@ int main(int argc, char *argv[]) {

                 kmod_setup();

 #endif

                 hostname_setup();

-                machine_id_setup();

+                machine_id_setup("");

                 loopback_setup();

                 test_mtab();

diff --git a/src/machine-id-setup/machine-id-setup-main.c b/src/machine-id-setup/machine-id-setup-main.c

index eb2d514..f4dc705 100644

--- a/src/machine-id-setup/machine-id-setup-main.c

+++ b/src/machine-id-setup/machine-id-setup-main.c

@@ -29,12 +29,15 @@

 #include "log.h"

 #include "build.h"

+static const char *arg_root = "";

+

 static int help(void) {

         printf("%s [OPTIONS...]\n\n"

                "Initialize /etc/machine-id from a random source.\n\n"

                "  -h --help             Show this help\n"

-               "     --version          Show package version\n",

+               "     --version          Show package version\n"

+               "     --root             Filesystem root\n",

                program_invocation_short_name);

         return 0;

@@ -43,13 +46,15 @@ static int help(void) {

 static int parse_argv(int argc, char *argv[]) {

         enum {

-                ARG_VERSION = 0x100

+                ARG_VERSION = 0x100,

+                ARG_ROOT,

         };

         static const struct option options[] = {

                 { "help",      no_argument,       NULL, 'h'           },

                 { "version",   no_argument,       NULL, ARG_VERSION   },

-                { NULL,        0,                 NULL, 0             }

+                { "root",      required_argument, NULL, ARG_ROOT      },

+                {}

         };

         int c;

@@ -70,6 +75,10 @@ static int parse_argv(int argc, char *argv[]) {

                         puts(SYSTEMD_FEATURES);

                         return 0;

+                case ARG_ROOT:

+                        arg_root = optarg;

+                        break;

+

                 case '?':

                         return -EINVAL;

@@ -97,5 +106,5 @@ int main(int argc, char *argv[]) {

         if (r <= 0)

                 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;

-        return machine_id_setup() < 0 ? EXIT_FAILURE : EXIT_SUCCESS;

+        return machine_id_setup(arg_root) < 0 ? EXIT_FAILURE : EXIT_SUCCESS;

 }