Adding upstream version 252.22.upstream/252.22upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1269 insertions, 0 deletions

diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c
new file mode 100644
index 0000000..63f0f36
--- /dev/null
+++ b/src/fstab-generator/fstab-generator.c
@@ -0,0 +1,1269 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "bus-error.h"
+#include "bus-locator.h"
+#include "chase-symlinks.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fstab-util.h"
+#include "generator.h"
+#include "in-addr-util.h"
+#include "log.h"
+#include "main-func.h"
+#include "mkdir.h"
+#include "mount-setup.h"
+#include "mount-util.h"
+#include "mountpoint-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "proc-cmdline.h"
+#include "process-util.h"
+#include "special.h"
+#include "specifier.h"
+#include "stat-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "unit-name.h"
+#include "util.h"
+#include "virt.h"
+#include "volatile-util.h"
+
+typedef enum MountPointFlags {
+        MOUNT_NOAUTO    = 1 << 0,
+        MOUNT_NOFAIL    = 1 << 1,
+        MOUNT_AUTOMOUNT = 1 << 2,
+        MOUNT_MAKEFS    = 1 << 3,
+        MOUNT_GROWFS    = 1 << 4,
+        MOUNT_RW_ONLY   = 1 << 5,
+} MountPointFlags;
+
+static bool arg_sysroot_check = false;
+static const char *arg_dest = NULL;
+static const char *arg_dest_late = NULL;
+static bool arg_fstab_enabled = true;
+static bool arg_swap_enabled = true;
+static char *arg_root_what = NULL;
+static char *arg_root_fstype = NULL;
+static char *arg_root_options = NULL;
+static char *arg_root_hash = NULL;
+static int arg_root_rw = -1;
+static char *arg_usr_what = NULL;
+static char *arg_usr_fstype = NULL;
+static char *arg_usr_options = NULL;
+static char *arg_usr_hash = NULL;
+static VolatileMode arg_volatile_mode = _VOLATILE_MODE_INVALID;
+
+STATIC_DESTRUCTOR_REGISTER(arg_root_what, freep);
+STATIC_DESTRUCTOR_REGISTER(arg_root_fstype, freep);
+STATIC_DESTRUCTOR_REGISTER(arg_root_options, freep);
+STATIC_DESTRUCTOR_REGISTER(arg_root_hash, freep);
+STATIC_DESTRUCTOR_REGISTER(arg_usr_what, freep);
+STATIC_DESTRUCTOR_REGISTER(arg_usr_fstype, freep);
+STATIC_DESTRUCTOR_REGISTER(arg_usr_options, freep);
+STATIC_DESTRUCTOR_REGISTER(arg_usr_hash, freep);
+
+static int write_options(FILE *f, const char *options) {
+        _cleanup_free_ char *o = NULL;
+
+        if (isempty(options))
+                return 0;
+
+        if (streq(options, "defaults"))
+                return 0;
+
+        o = specifier_escape(options);
+        if (!o)
+                return log_oom();
+
+        fprintf(f, "Options=%s\n", o);
+        return 1;
+}
+
+static int write_what(FILE *f, const char *what) {
+        _cleanup_free_ char *w = NULL;
+
+        w = specifier_escape(what);
+        if (!w)
+                return log_oom();
+
+        fprintf(f, "What=%s\n", w);
+        return 1;
+}
+
+static int add_swap(
+                const char *source,
+                const char *what,
+                struct mntent *me,
+                MountPointFlags flags) {
+
+        _cleanup_free_ char *name = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
+        int r;
+
+        assert(what);
+        assert(me);
+
+        if (!arg_swap_enabled) {
+                log_info("Swap unit generation disabled on kernel command line, ignoring fstab swap entry for %s.", what);
+                return 0;
+        }
+
+        if (access("/proc/swaps", F_OK) < 0) {
+                log_info("Swap not supported, ignoring fstab swap entry for %s.", what);
+                return 0;
+        }
+
+        if (detect_container() > 0) {
+                log_info("Running in a container, ignoring fstab swap entry for %s.", what);
+                return 0;
+        }
+
+        if (arg_sysroot_check) {
+                log_info("%s should be enabled in the initrd, will request daemon-reload.", what);
+                return true;
+        }
+
+        r = unit_name_from_path(what, ".swap", &name);
+        if (r < 0)
+                return log_error_errno(r, "Failed to generate unit name: %m");
+
+        r = generator_open_unit_file(arg_dest, source, name, &f);
+        if (r < 0)
+                return r;
+
+        fprintf(f,
+                "[Unit]\n"
+                "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n"
+                "SourcePath=%s\n",
+                source);
+
+        r = generator_write_blockdev_dependency(f, what);
+        if (r < 0)
+                return r;
+
+        fprintf(f,
+                "\n"
+                "[Swap]\n");
+
+        r = write_what(f, what);
+        if (r < 0)
+                return r;
+
+        r = write_options(f, me->mnt_opts);
+        if (r < 0)
+                return r;
+
+        r = fflush_and_check(f);
+        if (r < 0)
+                return log_error_errno(r, "Failed to write unit file %s: %m", name);
+
+        /* use what as where, to have a nicer error message */
+        r = generator_write_timeouts(arg_dest, what, what, me->mnt_opts, NULL);
+        if (r < 0)
+                return r;
+
+        if (flags & MOUNT_MAKEFS) {
+                r = generator_hook_up_mkswap(arg_dest, what);
+                if (r < 0)
+                        return r;
+        }
+
+        if (flags & MOUNT_GROWFS)
+                /* TODO: swap devices must be wiped and recreated */
+                log_warning("%s: growing swap devices is currently unsupported.", what);
+
+        if (!(flags & MOUNT_NOAUTO)) {
+                r = generator_add_symlink(arg_dest, SPECIAL_SWAP_TARGET,
+                                          (flags & MOUNT_NOFAIL) ? "wants" : "requires", name);
+                if (r < 0)
+                        return r;
+        }
+
+        return true;
+}
+
+static bool mount_is_network(struct mntent *me) {
+        assert(me);
+
+        return fstab_test_option(me->mnt_opts, "_netdev\0") ||
+               fstype_is_network(me->mnt_type);
+}
+
+static bool mount_in_initrd(struct mntent *me) {
+        assert(me);
+
+        return fstab_test_option(me->mnt_opts, "x-initrd.mount\0") ||
+               path_equal(me->mnt_dir, "/usr");
+}
+
+static int write_timeout(
+                FILE *f,
+                const char *where,
+                const char *opts,
+                const char *filter,
+                const char *variable) {
+
+        _cleanup_free_ char *timeout = NULL;
+        usec_t u;
+        int r;
+
+        r = fstab_filter_options(opts, filter, NULL, &timeout, NULL, NULL);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to parse options: %m");
+        if (r == 0)
+                return 0;
+
+        r = parse_sec_fix_0(timeout, &u);
+        if (r < 0) {
+                log_warning("Failed to parse timeout for %s, ignoring: %s", where, timeout);
+                return 0;
+        }
+
+        fprintf(f, "%s=%s\n", variable, FORMAT_TIMESPAN(u, 0));
+
+        return 0;
+}
+
+static int write_idle_timeout(FILE *f, const char *where, const char *opts) {
+        return write_timeout(f, where, opts,
+                             "x-systemd.idle-timeout\0", "TimeoutIdleSec");
+}
+
+static int write_mount_timeout(FILE *f, const char *where, const char *opts) {
+        return write_timeout(f, where, opts,
+                             "x-systemd.mount-timeout\0", "TimeoutSec");
+}
+
+static int write_dependency(
+                FILE *f,
+                const char *opts,
+                const char *filter,
+                const char *format) {
+
+        _cleanup_strv_free_ char **names = NULL, **units = NULL;
+        _cleanup_free_ char *res = NULL;
+        int r;
+
+        assert(f);
+        assert(opts);
+
+        r = fstab_filter_options(opts, filter, NULL, NULL, &names, NULL);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to parse options: %m");
+        if (r == 0)
+                return 0;
+
+        STRV_FOREACH(s, names) {
+                char *x;
+
+                r = unit_name_mangle_with_suffix(*s, "as dependency", 0, ".mount", &x);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to generate unit name: %m");
+
+                r = strv_consume(&units, x);
+                if (r < 0)
+                        return log_oom();
+        }
+
+        if (units) {
+                res = strv_join(units, " ");
+                if (!res)
+                        return log_oom();
+
+                DISABLE_WARNING_FORMAT_NONLITERAL;
+                fprintf(f, format, res);
+                REENABLE_WARNING;
+        }
+
+        return 0;
+}
+
+static int write_after(FILE *f, const char *opts) {
+        return write_dependency(f, opts,
+                                "x-systemd.after\0", "After=%1$s\n");
+}
+
+static int write_requires_after(FILE *f, const char *opts) {
+        return write_dependency(f, opts,
+                                "x-systemd.requires\0", "After=%1$s\nRequires=%1$s\n");
+}
+
+static int write_before(FILE *f, const char *opts) {
+        return write_dependency(f, opts,
+                                "x-systemd.before\0", "Before=%1$s\n");
+}
+
+static int write_requires_mounts_for(FILE *f, const char *opts) {
+        _cleanup_strv_free_ char **paths = NULL, **paths_escaped = NULL;
+        _cleanup_free_ char *res = NULL;
+        int r;
+
+        assert(f);
+        assert(opts);
+
+        r = fstab_filter_options(opts, "x-systemd.requires-mounts-for\0", NULL, NULL, &paths, NULL);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to parse options: %m");
+        if (r == 0)
+                return 0;
+
+        r = specifier_escape_strv(paths, &paths_escaped);
+        if (r < 0)
+                return log_error_errno(r, "Failed to escape paths: %m");
+
+        res = strv_join(paths_escaped, " ");
+        if (!res)
+                return log_oom();
+
+        fprintf(f, "RequiresMountsFor=%s\n", res);
+
+        return 0;
+}
+
+static int write_extra_dependencies(FILE *f, const char *opts) {
+        int r;
+
+        assert(f);
+
+        if (opts) {
+                r = write_after(f, opts);
+                if (r < 0)
+                        return r;
+                r = write_requires_after(f, opts);
+                if (r < 0)
+                        return r;
+                r = write_before(f, opts);
+                if (r < 0)
+                        return r;
+                r = write_requires_mounts_for(f, opts);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+static int add_mount(
+                const char *source,
+                const char *dest,
+                const char *what,
+                const char *where,
+                const char *original_where,
+                const char *fstype,
+                const char *opts,
+                int passno,
+                MountPointFlags flags,
+                const char *target_unit) {
+
+        _cleanup_free_ char
+                *name = NULL,
+                *automount_name = NULL,
+                *filtered = NULL,
+                *where_escaped = NULL;
+        _cleanup_strv_free_ char **wanted_by = NULL, **required_by = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
+        int r;
+
+        assert(what);
+        assert(where);
+        assert(opts);
+        assert(target_unit);
+        assert(source);
+
+        if (streq_ptr(fstype, "autofs"))
+                return 0;
+
+        if (!is_path(where)) {
+                log_warning("Mount point %s is not a valid path, ignoring.", where);
+                return 0;
+        }
+
+        if (mount_point_is_api(where) ||
+            mount_point_ignore(where))
+                return 0;
+
+        if (arg_sysroot_check) {
+                log_info("%s should be mounted in the initrd, will request daemon-reload.", where);
+                return true;
+        }
+
+        r = fstab_filter_options(opts, "x-systemd.wanted-by\0", NULL, NULL, &wanted_by, NULL);
+        if (r < 0)
+                return r;
+
+        r = fstab_filter_options(opts, "x-systemd.required-by\0", NULL, NULL, &required_by, NULL);
+        if (r < 0)
+                return r;
+
+        if (path_equal(where, "/")) {
+                if (flags & MOUNT_NOAUTO)
+                        log_warning("Ignoring \"noauto\" option for root device");
+                if (flags & MOUNT_NOFAIL)
+                        log_warning("Ignoring \"nofail\" option for root device");
+                if (flags & MOUNT_AUTOMOUNT)
+                        log_warning("Ignoring \"automount\" option for root device");
+                if (!strv_isempty(wanted_by))
+                        log_warning("Ignoring \"x-systemd.wanted-by=\" option for root device");
+                if (!strv_isempty(required_by))
+                        log_warning("Ignoring \"x-systemd.required-by=\" option for root device");
+
+                required_by = strv_free(required_by);
+                wanted_by = strv_free(wanted_by);
+                SET_FLAG(flags, MOUNT_NOAUTO | MOUNT_NOFAIL | MOUNT_AUTOMOUNT, false);
+        }
+
+        r = unit_name_from_path(where, ".mount", &name);
+        if (r < 0)
+                return log_error_errno(r, "Failed to generate unit name: %m");
+
+        r = generator_open_unit_file(dest, source, name, &f);
+        if (r < 0)
+                return r;
+
+        fprintf(f,
+                "[Unit]\n"
+                "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n"
+                "SourcePath=%s\n",
+                source);
+
+        if (STRPTR_IN_SET(fstype, "nfs", "nfs4") && !(flags & MOUNT_AUTOMOUNT) &&
+            fstab_test_yes_no_option(opts, "bg\0" "fg\0")) {
+                /* The default retry timeout that mount.nfs uses for 'bg' mounts
+                 * is 10000 minutes, where as it uses 2 minutes for 'fg' mounts.
+                 * As we are making  'bg' mounts look like an 'fg' mount to
+                 * mount.nfs (so systemd can manage the job-control aspects of 'bg'),
+                 * we need to explicitly preserve that default, and also ensure
+                 * the systemd mount-timeout doesn't interfere.
+                 * By placing these options first, they can be overridden by
+                 * settings in /etc/fstab. */
+                opts = strjoina("x-systemd.mount-timeout=infinity,retry=10000,nofail,", opts, ",fg");
+                SET_FLAG(flags, MOUNT_NOFAIL, true);
+        }
+
+        r = write_extra_dependencies(f, opts);
+        if (r < 0)
+                return r;
+
+        /* Order the mount unit we generate relative to target_unit, so that DefaultDependencies= on the
+         * target unit won't affect us. */
+        if (!FLAGS_SET(flags, MOUNT_NOFAIL))
+                fprintf(f, "Before=%s\n", target_unit);
+
+        if (passno != 0) {
+                r = generator_write_fsck_deps(f, dest, what, where, fstype);
+                if (r < 0)
+                        return r;
+        }
+
+        r = generator_write_blockdev_dependency(f, what);
+        if (r < 0)
+                return r;
+
+        fprintf(f,
+                "\n"
+                "[Mount]\n");
+
+        r = write_what(f, what);
+        if (r < 0)
+                return r;
+
+        if (original_where)
+                fprintf(f, "# Canonicalized from %s\n", original_where);
+
+        where_escaped = specifier_escape(where);
+        if (!where_escaped)
+                return log_oom();
+        fprintf(f, "Where=%s\n", where_escaped);
+
+        if (!isempty(fstype) && !streq(fstype, "auto")) {
+                _cleanup_free_ char *t = NULL;
+
+                t = specifier_escape(fstype);
+                if (!t)
+                        return -ENOMEM;
+
+                fprintf(f, "Type=%s\n", t);
+        }
+
+        r = generator_write_timeouts(dest, what, where, opts, &filtered);
+        if (r < 0)
+                return r;
+
+        r = generator_write_device_deps(dest, what, where, opts);
+        if (r < 0)
+                return r;
+
+        r = write_mount_timeout(f, where, opts);
+        if (r < 0)
+                return r;
+
+        r = write_options(f, filtered);
+        if (r < 0)
+                return r;
+
+        if (flags & MOUNT_RW_ONLY)
+                fprintf(f, "ReadWriteOnly=yes\n");
+
+        r = fflush_and_check(f);
+        if (r < 0)
+                return log_error_errno(r, "Failed to write unit file %s: %m", name);
+
+        if (flags & MOUNT_MAKEFS) {
+                r = generator_hook_up_mkfs(dest, what, where, fstype);
+                if (r < 0)
+                        return r;
+        }
+
+        if (flags & MOUNT_GROWFS) {
+                r = generator_hook_up_growfs(dest, where, target_unit);
+                if (r < 0)
+                        return r;
+        }
+
+        if (!FLAGS_SET(flags, MOUNT_AUTOMOUNT)) {
+                if (!FLAGS_SET(flags, MOUNT_NOAUTO) && strv_isempty(wanted_by) && strv_isempty(required_by)) {
+                        r = generator_add_symlink(dest, target_unit,
+                                                  (flags & MOUNT_NOFAIL) ? "wants" : "requires", name);
+                        if (r < 0)
+                                return r;
+                } else {
+                        STRV_FOREACH(s, wanted_by) {
+                                r = generator_add_symlink(dest, *s, "wants", name);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        STRV_FOREACH(s, required_by) {
+                                r = generator_add_symlink(dest, *s, "requires", name);
+                                if (r < 0)
+                                        return r;
+                        }
+                }
+        } else {
+                r = unit_name_from_path(where, ".automount", &automount_name);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to generate unit name: %m");
+
+                f = safe_fclose(f);
+
+                r = generator_open_unit_file(dest, source, automount_name, &f);
+                if (r < 0)
+                        return r;
+
+                fprintf(f,
+                        "[Unit]\n"
+                        "SourcePath=%s\n"
+                        "Documentation=man:fstab(5) man:systemd-fstab-generator(8)\n",
+                        source);
+
+                fprintf(f,
+                        "\n"
+                        "[Automount]\n"
+                        "Where=%s\n",
+                        where_escaped);
+
+                r = write_idle_timeout(f, where, opts);
+                if (r < 0)
+                        return r;
+
+                r = fflush_and_check(f);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to write unit file %s: %m", automount_name);
+
+                r = generator_add_symlink(dest, target_unit,
+                                          (flags & MOUNT_NOFAIL) ? "wants" : "requires", automount_name);
+                if (r < 0)
+                        return r;
+        }
+
+        return true;
+}
+
+static int do_daemon_reload(void) {
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        int r, k;
+
+        log_debug("Calling org.freedesktop.systemd1.Manager.Reload()...");
+
+        r = bus_connect_system_systemd(&bus);
+        if (r < 0)
+                return log_error_errno(r, "Failed to get D-Bus connection: %m");
+
+        r = bus_message_new_method_call(bus, &m, bus_systemd_mgr, "Reload");
+        if (r < 0)
+                return bus_log_create_error(r);
+
+        r = sd_bus_call(bus, m, DAEMON_RELOAD_TIMEOUT_SEC, &error, NULL);
+        if (r < 0)
+                return log_error_errno(r, "Failed to reload daemon: %s", bus_error_message(&error, r));
+
+        /* We need to requeue the two targets so that any new units which previously were not part of the
+         * targets, and which we now added, will be started. */
+
+        r = 0;
+        FOREACH_STRING(unit, SPECIAL_INITRD_FS_TARGET, SPECIAL_SWAP_TARGET) {
+                log_info("Requesting %s/start/replace...", unit);
+
+                k = sd_bus_call_method(bus,
+                                       "org.freedesktop.systemd1",
+                                       "/org/freedesktop/systemd1",
+                                       "org.freedesktop.systemd1.Manager",
+                                       "StartUnit",
+                                       &error,
+                                       NULL,
+                                       "ss", unit, "replace");
+                if (k < 0) {
+                        log_error_errno(k, "Failed to (re)start %s: %s", unit, bus_error_message(&error, r));
+                        if (r == 0)
+                                r = k;
+                }
+        }
+
+        return r;
+}
+
+static const char* sysroot_fstab_path(void) {
+        return getenv("SYSTEMD_SYSROOT_FSTAB") ?: "/sysroot/etc/fstab";
+}
+
+static int parse_fstab(bool initrd) {
+        _cleanup_endmntent_ FILE *f = NULL;
+        const char *fstab;
+        struct mntent *me;
+        int r = 0;
+
+        if (initrd)
+                fstab = sysroot_fstab_path();
+        else {
+                fstab = fstab_path();
+                assert(!arg_sysroot_check);
+        }
+
+        log_debug("Parsing %s...", fstab);
+
+        f = setmntent(fstab, "re");
+        if (!f) {
+                if (errno == ENOENT)
+                        return 0;
+
+                return log_error_errno(errno, "Failed to open %s: %m", fstab);
+        }
+
+        while ((me = getmntent(f))) {
+                _cleanup_free_ char *where = NULL, *what = NULL, *canonical_where = NULL;
+                bool makefs, growfs, noauto, nofail;
+                MountPointFlags flags;
+                int k;
+
+                if (initrd && !mount_in_initrd(me))
+                        continue;
+
+                what = fstab_node_to_udev_node(me->mnt_fsname);
+                if (!what)
+                        return log_oom();
+
+                if (path_is_read_only_fs("/sys") > 0) {
+                        if (streq(what, "sysfs")) {
+                                log_info("Running in a container, ignoring fstab entry for %s.", what);
+                                continue;
+                        }
+
+                        if (is_device_path(what)) {
+                                log_info("Running in a container, ignoring fstab device entry for %s.", what);
+                                continue;
+                        }
+                }
+
+                where = strdup(me->mnt_dir);
+                if (!where)
+                        return log_oom();
+
+                if (is_path(where)) {
+                        path_simplify(where);
+
+                        /* Follow symlinks here; see 5261ba901845c084de5a8fd06500ed09bfb0bd80 which makes sense for
+                         * mount units, but causes problems since it historically worked to have symlinks in e.g.
+                         * /etc/fstab. So we canonicalize here. Note that we use CHASE_NONEXISTENT to handle the case
+                         * where a symlink refers to another mount target; this works assuming the sub-mountpoint
+                         * target is the final directory.
+                         *
+                         * FIXME: when chase_symlinks() learns to chase non-existent paths, use this here and
+                         *        drop the prefixing with /sysroot on error below.
+                         */
+                        k = chase_symlinks(where, initrd ? "/sysroot" : NULL,
+                                           CHASE_PREFIX_ROOT | CHASE_NONEXISTENT,
+                                           &canonical_where, NULL);
+                        if (k < 0) {
+                                /* If we can't canonicalize, continue as if it wasn't a symlink */
+                                log_debug_errno(k, "Failed to read symlink target for %s, using as-is: %m", where);
+
+                                if (initrd) {
+                                        canonical_where = path_join("/sysroot", where);
+                                        if (!canonical_where)
+                                                return log_oom();
+                                }
+
+                        } else if (streq(canonical_where, where)) /* If it was fully canonicalized, suppress the change */
+                                canonical_where = mfree(canonical_where);
+                        else
+                                log_debug("Canonicalized what=%s where=%s to %s", what, where, canonical_where);
+                }
+
+                makefs = fstab_test_option(me->mnt_opts, "x-systemd.makefs\0");
+                growfs = fstab_test_option(me->mnt_opts, "x-systemd.growfs\0");
+                noauto = fstab_test_yes_no_option(me->mnt_opts, "noauto\0" "auto\0");
+                nofail = fstab_test_yes_no_option(me->mnt_opts, "nofail\0" "fail\0");
+
+                log_debug("Found entry what=%s where=%s type=%s makefs=%s growfs=%s noauto=%s nofail=%s",
+                          what, where, me->mnt_type,
+                          yes_no(makefs), yes_no(growfs),
+                          yes_no(noauto), yes_no(nofail));
+
+                flags = makefs * MOUNT_MAKEFS |
+                        growfs * MOUNT_GROWFS |
+                        noauto * MOUNT_NOAUTO |
+                        nofail * MOUNT_NOFAIL;
+
+                if (streq(me->mnt_type, "swap"))
+                        k = add_swap(fstab, what, me, flags);
+                else {
+                        bool rw_only, automount;
+
+                        rw_only = fstab_test_option(me->mnt_opts, "x-systemd.rw-only\0");
+                        automount = fstab_test_option(me->mnt_opts,
+                                                      "comment=systemd.automount\0"
+                                                      "x-systemd.automount\0");
+
+                        flags |= rw_only * MOUNT_RW_ONLY |
+                                 automount * MOUNT_AUTOMOUNT;
+
+                        const char *target_unit =
+                                initrd ?               SPECIAL_INITRD_FS_TARGET :
+                                mount_is_network(me) ? SPECIAL_REMOTE_FS_TARGET :
+                                                       SPECIAL_LOCAL_FS_TARGET;
+
+                        k = add_mount(fstab,
+                                      arg_dest,
+                                      what,
+                                      canonical_where ?: where,
+                                      canonical_where ? where: NULL,
+                                      me->mnt_type,
+                                      me->mnt_opts,
+                                      me->mnt_passno,
+                                      flags,
+                                      target_unit);
+                }
+
+                if (arg_sysroot_check && k > 0)
+                        return true;  /* We found a mount or swap that would be started… */
+                if (r >= 0 && k < 0)
+                        r = k;
+        }
+
+        return r;
+}
+
+static int sysroot_is_nfsroot(void) {
+        union in_addr_union u;
+        const char *sep, *a;
+        int r;
+
+        assert(arg_root_what);
+
+        /* From dracut.cmdline(7).
+         *
+         * root=[<server-ip>:]<root-dir>[:<nfs-options>]
+         * root=nfs:[<server-ip>:]<root-dir>[:<nfs-options>],
+         * root=nfs4:[<server-ip>:]<root-dir>[:<nfs-options>],
+         * root={dhcp|dhcp6}
+         *
+         * mount nfs share from <server-ip>:/<root-dir>, if no server-ip is given, use dhcp next_server.
+         * If server-ip is an IPv6 address it has to be put in brackets, e.g. [2001:DB8::1]. NFS options
+         * can be appended with the prefix ":" or "," and are separated by ",". */
+
+        if (path_equal(arg_root_what, "/dev/nfs") ||
+            STR_IN_SET(arg_root_what, "dhcp", "dhcp6") ||
+            STARTSWITH_SET(arg_root_what, "nfs:", "nfs4:"))
+                return true;
+
+        /* IPv6 address */
+        if (arg_root_what[0] == '[') {
+                sep = strchr(arg_root_what + 1, ']');
+                if (!sep)
+                        return -EINVAL;
+
+                a = strndupa_safe(arg_root_what + 1, sep - arg_root_what - 1);
+
+                r = in_addr_from_string(AF_INET6, a, &u);
+                if (r < 0)
+                        return r;
+
+                return true;
+        }
+
+        /* IPv4 address */
+        sep = strchr(arg_root_what, ':');
+        if (sep) {
+                a = strndupa_safe(arg_root_what, sep - arg_root_what);
+
+                if (in_addr_from_string(AF_INET, a, &u) >= 0)
+                        return true;
+        }
+
+        /* root directory without address */
+        return path_is_absolute(arg_root_what) && !path_startswith(arg_root_what, "/dev");
+}
+
+static int add_sysroot_mount(void) {
+        _cleanup_free_ char *what = NULL;
+        const char *opts, *fstype;
+        bool default_rw;
+        int r;
+
+        if (isempty(arg_root_what)) {
+                log_debug("Could not find a root= entry on the kernel command line.");
+                return 0;
+        }
+
+        if (streq(arg_root_what, "gpt-auto")) {
+                /* This is handled by gpt-auto-generator */
+                log_debug("Skipping root directory handling, as gpt-auto was requested.");
+                return 0;
+        }
+
+        r = sysroot_is_nfsroot();
+        if (r < 0)
+                log_debug_errno(r, "Failed to determine if the root directory is on NFS, assuming not: %m");
+        else if (r > 0) {
+                /* This is handled by the kernel or the initrd */
+                log_debug("Skipping root directory handling, as root on NFS was requested.");
+                return 0;
+        }
+
+        if (startswith(arg_root_what, "cifs://")) {
+                log_debug("Skipping root directory handling, as root on CIFS was requested.");
+                return 0;
+        }
+
+        if (startswith(arg_root_what, "iscsi:")) {
+                log_debug("Skipping root directory handling, as root on iSCSI was requested.");
+                return 0;
+        }
+
+        if (startswith(arg_root_what, "live:")) {
+                log_debug("Skipping root directory handling, as root on live image was requested.");
+                return 0;
+        }
+
+        if (streq(arg_root_what, "tmpfs")) {
+                /* If root=tmpfs is specified, then take this as shortcut for a writable tmpfs mount as root */
+
+                what = strdup("rootfs"); /* just a pretty name, to show up in /proc/self/mountinfo */
+                if (!what)
+                        return log_oom();
+
+                fstype = arg_root_fstype ?: "tmpfs"; /* tmpfs, unless overridden */
+
+                default_rw = true; /* writable, unless overridden */;
+        } else {
+
+                what = fstab_node_to_udev_node(arg_root_what);
+                if (!what)
+                        return log_oom();
+
+                fstype = arg_root_fstype; /* if not specified explicitly, don't default to anything here */
+
+                default_rw = false; /* read-only, unless overridden */
+        }
+
+        if (!arg_root_options)
+                opts = arg_root_rw > 0 || (arg_root_rw < 0 && default_rw) ? "rw" : "ro";
+        else if (arg_root_rw >= 0 ||
+                 !fstab_test_option(arg_root_options, "ro\0" "rw\0"))
+                opts = strjoina(arg_root_options, ",", arg_root_rw > 0 ? "rw" : "ro");
+        else
+                opts = arg_root_options;
+
+        log_debug("Found entry what=%s where=/sysroot type=%s opts=%s", what, strna(arg_root_fstype), strempty(opts));
+
+        if (is_device_path(what)) {
+                r = generator_write_initrd_root_device_deps(arg_dest, what);
+                if (r < 0)
+                        return r;
+        }
+
+        return add_mount("/proc/cmdline",
+                         arg_dest,
+                         what,
+                         "/sysroot",
+                         NULL,
+                         fstype,
+                         opts,
+                         is_device_path(what) ? 1 : 0, /* passno */
+                         0,                            /* makefs off, growfs off, noauto off, nofail off, automount off */
+                         SPECIAL_INITRD_ROOT_FS_TARGET);
+}
+
+static int add_sysroot_usr_mount(void) {
+        _cleanup_free_ char *what = NULL;
+        const char *opts;
+        int r;
+
+        /* Returns 0 if we didn't do anything, > 0 if we either generated a unit for the /usr/ mount, or we
+         * know for sure something else did */
+
+        if (!arg_usr_what && !arg_usr_fstype && !arg_usr_options)
+                return 0;
+
+        if (arg_root_what && !arg_usr_what) {
+                /* Copy over the root device, in case the /usr mount just differs in a mount option (consider btrfs subvolumes) */
+                arg_usr_what = strdup(arg_root_what);
+                if (!arg_usr_what)
+                        return log_oom();
+        }
+
+        if (arg_root_fstype && !arg_usr_fstype) {
+                arg_usr_fstype = strdup(arg_root_fstype);
+                if (!arg_usr_fstype)
+                        return log_oom();
+        }
+
+        if (arg_root_options && !arg_usr_options) {
+                arg_usr_options = strdup(arg_root_options);
+                if (!arg_usr_options)
+                        return log_oom();
+        }
+
+        if (isempty(arg_usr_what)) {
+                log_debug("Could not find a mount.usr= entry on the kernel command line.");
+                return 0;
+        }
+
+        if (streq(arg_usr_what, "gpt-auto")) {
+                /* This is handled by the gpt-auto generator */
+                log_debug("Skipping /usr/ directory handling, as gpt-auto was requested.");
+                return 1; /* systemd-gpt-auto-generator will generate a unit for this, hence report that a
+                           * unit file is being created for the host /usr/ mount. */
+        }
+
+        if (path_equal(arg_usr_what, "/dev/nfs")) {
+                /* This is handled by the initrd (if at all supported, that is) */
+                log_debug("Skipping /usr/ directory handling, as /dev/nfs was requested.");
+                return 1; /* As above, report that NFS code will create the unit */
+        }
+
+        what = fstab_node_to_udev_node(arg_usr_what);
+        if (!what)
+                return log_oom();
+
+        if (!arg_usr_options)
+                opts = arg_root_rw > 0 ? "rw" : "ro";
+        else if (!fstab_test_option(arg_usr_options, "ro\0" "rw\0"))
+                opts = strjoina(arg_usr_options, ",", arg_root_rw > 0 ? "rw" : "ro");
+        else
+                opts = arg_usr_options;
+
+        /* When mounting /usr from the initrd, we add an extra level of indirection: we first mount the /usr/
+         * partition to /sysusr/usr/, and then afterwards bind mount that to /sysroot/usr/. We do this so
+         * that we can cover for systems that initially only have a /usr/ around and where the root fs needs
+         * to be synthesized, based on configuration included in /usr/, e.g. systemd-repart. Software like
+         * this should order itself after initrd-usr-fs.target and before initrd-fs.target; and it should
+         * look into both /sysusr/ and /sysroot/ for the configuration data to apply. */
+
+        log_debug("Found entry what=%s where=/sysusr/usr type=%s opts=%s", what, strna(arg_usr_fstype), strempty(opts));
+
+        r = add_mount("/proc/cmdline",
+                      arg_dest,
+                      what,
+                      "/sysusr/usr",
+                      NULL,
+                      arg_usr_fstype,
+                      opts,
+                      is_device_path(what) ? 1 : 0, /* passno */
+                      0,
+                      SPECIAL_INITRD_USR_FS_TARGET);
+        if (r < 0)
+                return r;
+
+        log_debug("Synthesizing entry what=/sysusr/usr where=/sysrootr/usr opts=bind");
+
+        r = add_mount("/proc/cmdline",
+                      arg_dest,
+                      "/sysusr/usr",
+                      "/sysroot/usr",
+                      NULL,
+                      NULL,
+                      "bind",
+                      0,
+                      0,
+                      SPECIAL_INITRD_FS_TARGET);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
+static int add_sysroot_usr_mount_or_fallback(void) {
+        int r;
+
+        r = add_sysroot_usr_mount();
+        if (r != 0)
+                return r;
+
+        /* OK, so we didn't write anything out for /sysusr/usr/ nor /sysroot/usr/. In this case, let's make
+         * sure that initrd-usr-fs.target is at least ordered after sysroot.mount so that services that order
+         * themselves get the guarantee that /usr/ is definitely mounted somewhere. */
+
+        return generator_add_symlink(
+                        arg_dest,
+                        SPECIAL_INITRD_USR_FS_TARGET,
+                        "requires",
+                        "sysroot.mount");
+}
+
+static int add_volatile_root(void) {
+
+        /* Let's add in systemd-remount-volatile.service which will remount the root device to tmpfs if this is
+         * requested (or as an overlayfs), leaving only /usr from the root mount inside. */
+
+        if (!IN_SET(arg_volatile_mode, VOLATILE_YES, VOLATILE_OVERLAY))
+                return 0;
+
+        return generator_add_symlink(arg_dest, SPECIAL_INITRD_ROOT_FS_TARGET, "requires",
+                                     SYSTEM_DATA_UNIT_DIR "/" SPECIAL_VOLATILE_ROOT_SERVICE);
+}
+
+static int add_volatile_var(void) {
+
+        if (arg_volatile_mode != VOLATILE_STATE)
+                return 0;
+
+        /* If requested, mount /var as tmpfs, but do so only if there's nothing else defined for this. */
+
+        return add_mount("/proc/cmdline",
+                         arg_dest_late,
+                         "tmpfs",
+                         "/var",
+                         NULL,
+                         "tmpfs",
+                         "mode=0755" TMPFS_LIMITS_VAR,
+                         0,
+                         0,
+                         SPECIAL_LOCAL_FS_TARGET);
+}
+
+static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
+        int r;
+
+        /* root=, usr=, usrfstype= and roofstype= may occur more than once, the last
+         * instance should take precedence.  In the case of multiple rootflags=
+         * or usrflags= the arguments should be concatenated */
+
+        if (STR_IN_SET(key, "fstab", "rd.fstab")) {
+
+                r = value ? parse_boolean(value) : 1;
+                if (r < 0)
+                        log_warning("Failed to parse fstab switch %s. Ignoring.", value);
+                else
+                        arg_fstab_enabled = r;
+
+        } else if (streq(key, "root")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                return free_and_strdup_warn(&arg_root_what, value);
+
+        } else if (streq(key, "rootfstype")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                return free_and_strdup_warn(&arg_root_fstype, value);
+
+        } else if (streq(key, "rootflags")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                if (!strextend_with_separator(&arg_root_options, ",", value))
+                        return log_oom();
+
+        } else if (streq(key, "roothash")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                return free_and_strdup_warn(&arg_root_hash, value);
+
+        } else if (streq(key, "mount.usr")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                return free_and_strdup_warn(&arg_usr_what, value);
+
+        } else if (streq(key, "mount.usrfstype")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                return free_and_strdup_warn(&arg_usr_fstype, value);
+
+        } else if (streq(key, "mount.usrflags")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                if (!strextend_with_separator(&arg_usr_options, ",", value))
+                        return log_oom();
+
+        } else if (streq(key, "usrhash")) {
+
+                if (proc_cmdline_value_missing(key, value))
+                        return 0;
+
+                return free_and_strdup_warn(&arg_usr_hash, value);
+
+        } else if (streq(key, "rw") && !value)
+                arg_root_rw = true;
+        else if (streq(key, "ro") && !value)
+                arg_root_rw = false;
+        else if (streq(key, "systemd.volatile")) {
+                VolatileMode m;
+
+                if (value) {
+                        m = volatile_mode_from_string(value);
+                        if (m < 0)
+                                log_warning_errno(m, "Failed to parse systemd.volatile= argument: %s", value);
+                        else
+                                arg_volatile_mode = m;
+                } else
+                        arg_volatile_mode = VOLATILE_YES;
+
+        } else if (streq(key, "systemd.swap")) {
+
+                r = value ? parse_boolean(value) : 1;
+                if (r < 0)
+                        log_warning("Failed to parse systemd.swap switch %s. Ignoring.", value);
+                else
+                        arg_swap_enabled = r;
+        }
+
+        return 0;
+}
+
+static int determine_device(char **what, const char *hash, const char *name) {
+
+        assert(what);
+        assert(name);
+
+        /* If we have a hash but no device then Verity is used, and we use the DM device. */
+        if (*what)
+                return 0;
+
+        if (!hash)
+                return 0;
+
+        *what = path_join("/dev/mapper/", name);
+        if (!*what)
+                return log_oom();
+
+        log_info("Using verity %s device %s.", name, *what);
+
+        return 1;
+}
+
+static int determine_root(void) {
+        return determine_device(&arg_root_what, arg_root_hash, "root");
+}
+
+static int determine_usr(void) {
+        return determine_device(&arg_usr_what, arg_usr_hash, "usr");
+}
+
+/* If arg_sysroot_check is false, run as generator in the usual fashion.
+ * If it is true, check /sysroot/etc/fstab for any units that we'd want to mount
+ * in the initrd, and call daemon-reload. We will get reinvoked as a generator,
+ * with /sysroot/etc/fstab available, and then we can write additional units based
+ * on that file. */
+static int run_generator(void) {
+        int r, r2 = 0, r3 = 0;
+
+        r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
+        if (r < 0)
+                log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
+
+        (void) determine_root();
+        (void) determine_usr();
+
+        if (arg_sysroot_check) {
+                r = parse_fstab(true);
+                if (r == 0)
+                        log_debug("Nothing interesting found, not doing daemon-reload.");
+                if (r > 0)
+                        r = do_daemon_reload();
+                return r;
+        }
+
+        /* Always honour root= and usr= in the kernel command line if we are in an initrd */
+        if (in_initrd()) {
+                r = add_sysroot_mount();
+
+                r2 = add_sysroot_usr_mount_or_fallback();
+
+                r3 = add_volatile_root();
+        } else
+                r = add_volatile_var();
+
+        /* Honour /etc/fstab only when that's enabled */
+        if (arg_fstab_enabled) {
+                /* Parse the local /etc/fstab, possibly from the initrd */
+                r2 = parse_fstab(false);
+
+                /* If running in the initrd also parse the /etc/fstab from the host */
+                if (in_initrd())
+                        r3 = parse_fstab(true);
+                else
+                        r3 = generator_enable_remount_fs_service(arg_dest);
+        }
+
+        return r < 0 ? r : r2 < 0 ? r2 : r3;
+}
+
+static int run(int argc, char **argv) {
+        arg_sysroot_check = invoked_as(argv, "systemd-sysroot-fstab-check");
+
+        if (arg_sysroot_check) {
+                /* Run as in systemd-sysroot-fstab-check mode */
+                log_setup();
+
+                if (strv_length(argv) > 1)
+                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "This program takes no arguments.");
+                if (!in_initrd())
+                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "This program is only useful in the initrd.");
+        } else {
+                /* Run in generator mode */
+                log_setup_generator();
+
+                if (!IN_SET(strv_length(argv), 2, 4))
+                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "This program takes one or three arguments.");
+
+                arg_dest = ASSERT_PTR(argv[1]);
+                arg_dest_late = ASSERT_PTR(argv[argc > 3 ? 3 : 1]);
+        }
+
+        return run_generator();
+}
+
+DEFINE_MAIN_FUNCTION(run);