From 99c06d718c91c91d0992869777c15b457f95443a Mon Sep 17 00:00:00 2001 From: Greg KH 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 . --> - + systemd-machine-id-setup @@ -96,19 +97,15 @@ - - - - Prints a short help - text and exits. - - - - - - Prints a short version - string and exits. + + Takes a directory path + as an argument. All paths will be + prefixed with the given alternate ROOT + path, including config search paths. + + + 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 . ***/ -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; }