Merge pull request #28518 from yuwata/fstab-generator-fixes

fstab-generator: fixes for systemd.mount-extra=

Author: bluca

man/systemd-fstab-generator.xml

@@ -242,11 +242,15 @@
 
       <varlistentry>
         <term><varname>systemd.mount-extra=<replaceable>WHAT</replaceable>:<replaceable>WHERE</replaceable>[:<replaceable>FSTYPE</replaceable>[:<replaceable>OPTIONS</replaceable>]]</varname></term>
+        <term><varname>rd.systemd.mount-extra=<replaceable>WHAT</replaceable>:<replaceable>WHERE</replaceable>[:<replaceable>FSTYPE</replaceable>[:<replaceable>OPTIONS</replaceable>]]</varname></term>
 
         <listitem>
           <para>Specifies the mount unit. Takes at least two and at most four fields separated with a colon
           (<literal>:</literal>). Each field is handled as the corresponding fstab field. This option can be
-          specified multiple times.</para>
+          specified multiple times. <varname>rd.systemd.mount-extra=</varname> is honored only in the initrd,
+          while <varname>systemd.mount-extra=</varname> is honored by both the main system and the initrd.
+          In the initrd, the mount point (and also source path if the mount is bind mount) specified in
+          <varname>systemd.mount-extra=</varname> is prefixed with <filename>/sysroot/</filename>.</para>
           <para>Example:
           <programlisting>
 systemd.mount-extra=/dev/sda1:/mount-point:ext4:rw,noatime</programlisting>
@@ -256,10 +260,13 @@ systemd.mount-extra=/dev/sda1:/mount-point:ext4:rw,noatime</programlisting>
 
       <varlistentry>
         <term><varname>systemd.swap-extra=<replaceable>WHAT</replaceable>[:<replaceable>OPTIONS</replaceable>]</varname></term>
+        <term><varname>rd.systemd.swap-extra=<replaceable>WHAT</replaceable>[:<replaceable>OPTIONS</replaceable>]</varname></term>
 
         <listitem>
           <para>Specifies the swap unit. Takes the block device to be used as a swap device, and optionally
-          takes mount options followed by a colon (<literal>:</literal>).</para>
+          takes mount options followed by a colon (<literal>:</literal>). This option can be specified
+          multiple times. <varname>rd.systemd.swap-extra=</varname> is honored only in the initrd, while
+          <varname>systemd.swap-extra=</varname> is honored by both the main system and the initrd.</para>
           <para>Example:
           <programlisting>
 systemd.swap=/dev/sda2:x-systemd.makefs</programlisting>

src/fstab-generator/fstab-generator.c

@@ -49,6 +49,7 @@ typedef enum MountPointFlags {
 } MountPointFlags;
 
 typedef struct Mount {
+        bool for_initrd;
         char *what;
         char *where;
         char *fstype;
@@ -102,7 +103,13 @@ static void mount_array_free(Mount *mounts, size_t n) {
         free(mounts);
 }
 
-static int mount_array_add_internal(char *in_what, char *in_where, const char *in_fstype, const char *in_options) {
+static int mount_array_add_internal(
+                bool for_initrd,
+                char *in_what,
+                char *in_where,
+                const char *in_fstype,
+                const char *in_options) {
+
         _cleanup_free_ char *what = NULL, *where = NULL, *fstype = NULL, *options = NULL;
         int r;
 
@@ -135,6 +142,7 @@ static int mount_array_add_internal(char *in_what, char *in_where, const char *i
                 return -ENOMEM;
 
         arg_mounts[arg_n_mounts++] = (Mount) {
+                .for_initrd = for_initrd,
                 .what = TAKE_PTR(what),
                 .where = TAKE_PTR(where),
                 .fstype = TAKE_PTR(fstype),
@@ -144,7 +152,7 @@ static int mount_array_add_internal(char *in_what, char *in_where, const char *i
         return 0;
 }
 
-static int mount_array_add(const char *str) {
+static int mount_array_add(bool for_initrd, const char *str) {
         _cleanup_free_ char *what = NULL, *where = NULL, *fstype = NULL, *options = NULL;
         int r;
 
@@ -159,10 +167,10 @@ static int mount_array_add(const char *str) {
         if (!isempty(str))
                 return -EINVAL;
 
-        return mount_array_add_internal(TAKE_PTR(what), TAKE_PTR(where), fstype, options);
+        return mount_array_add_internal(for_initrd, TAKE_PTR(what), TAKE_PTR(where), fstype, options);
 }
 
-static int mount_array_add_swap(const char *str) {
+static int mount_array_add_swap(bool for_initrd, const char *str) {
         _cleanup_free_ char *what = NULL, *options = NULL;
         int r;
 
@@ -177,7 +185,7 @@ static int mount_array_add_swap(const char *str) {
         if (!isempty(str))
                 return -EINVAL;
 
-        return mount_array_add_internal(TAKE_PTR(what), NULL, "swap", options);
+        return mount_array_add_internal(for_initrd, TAKE_PTR(what), NULL, "swap", options);
 }
 
 static int write_options(FILE *f, const char *options) {
@@ -306,9 +314,9 @@ static bool mount_is_network(const char *fstype, const char *options) {
                 (fstype && fstype_is_network(fstype));
 }
 
-static bool mount_in_initrd(const char *where, const char *options) {
+static bool mount_in_initrd(const char *where, const char *options, bool accept_root) {
         return fstab_test_option(options, "x-initrd.mount\0") ||
-                (where && path_equal(where, "/usr"));
+                (where && PATH_IN_SET(where, "/usr", accept_root ? "/" : NULL));
 }
 
 static int write_timeout(
@@ -801,7 +809,7 @@ static MountPointFlags fstab_options_to_flags(const char *options, bool is_swap)
         return flags;
 }
 
-static int canonicalize_mount_path(const char *path, const char *type, bool initrd, char **ret) {
+static int canonicalize_mount_path(const char *path, const char *type, bool prefix_sysroot, char **ret) {
         _cleanup_free_ char *p = NULL;
         bool changed;
         int r;
@@ -813,11 +821,11 @@ static int canonicalize_mount_path(const char *path, const char *type, bool init
 
         // FIXME: when chase() learns to chase non-existent paths, use this here and drop the prefixing with
         // /sysroot on error below.
-        r = chase(path, initrd ? "/sysroot" : NULL, CHASE_PREFIX_ROOT | CHASE_NONEXISTENT, &p, NULL);
+        r = chase(path, prefix_sysroot ? "/sysroot" : NULL, CHASE_PREFIX_ROOT | CHASE_NONEXISTENT, &p, NULL);
         if (r < 0) {
                 log_debug_errno(r, "Failed to chase '%s', using as-is: %m", path);
 
-                if (initrd)
+                if (prefix_sysroot)
                         p = path_join("/sysroot", path);
                 else
                         p = strdup(path);
@@ -842,7 +850,8 @@ static int parse_fstab_one(
                 const char *fstype,
                 const char *options,
                 int passno,
-                bool initrd,
+                bool prefix_sysroot,
+                bool accept_root, /* This takes an effect only when prefix_sysroot is true. */
                 bool use_swap_enabled) {
 
         _cleanup_free_ char *what = NULL, *where = NULL;
@@ -854,7 +863,7 @@ static int parse_fstab_one(
         assert(fstype);
         assert(options);
 
-        if (initrd && !mount_in_initrd(where_original, options))
+        if (prefix_sysroot && !mount_in_initrd(where_original, options, accept_root))
                 return 0;
 
         is_swap = streq_ptr(fstype, "swap");
@@ -891,16 +900,16 @@ static int parse_fstab_one(
          * /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. */
-        r = canonicalize_mount_path(where_original, "where", initrd, &where);
+        r = canonicalize_mount_path(where_original, "where", prefix_sysroot, &where);
         if (r < 0)
                 return r;
         where_changed = r > 0;
 
-        if (initrd && fstab_is_bind(options, fstype)) {
+        if (prefix_sysroot && fstab_is_bind(options, fstype)) {
                 /* When in initrd, the source of bind mount needs to be prepended with /sysroot as well. */
                 _cleanup_free_ char *p = NULL;
 
-                r = canonicalize_mount_path(what, "what", initrd, &p);
+                r = canonicalize_mount_path(what, "what", prefix_sysroot, &p);
                 if (r < 0)
                         return r;
 
@@ -919,9 +928,9 @@ static int parse_fstab_one(
         bool is_sysroot_usr = in_initrd() && path_equal(where, "/sysroot/usr");
 
         const char *target_unit =
-                        initrd ?                            SPECIAL_INITRD_FS_TARGET :
                         is_sysroot ?                        SPECIAL_INITRD_ROOT_FS_TARGET :
                         is_sysroot_usr ?                    SPECIAL_INITRD_USR_FS_TARGET :
+                        prefix_sysroot ?                    SPECIAL_INITRD_FS_TARGET :
                         mount_is_network(fstype, options) ? SPECIAL_REMOTE_FS_TARGET :
                                                             SPECIAL_LOCAL_FS_TARGET;
 
@@ -948,13 +957,13 @@ static int parse_fstab_one(
         return true;
 }
 
-static int parse_fstab(bool initrd) {
+static int parse_fstab(bool prefix_sysroot) {
         _cleanup_endmntent_ FILE *f = NULL;
         const char *fstab;
         struct mntent *me;
         int r, ret = 0;
 
-        if (initrd)
+        if (prefix_sysroot)
                 fstab = sysroot_fstab_path();
         else {
                 fstab = fstab_path();
@@ -974,7 +983,9 @@ static int parse_fstab(bool initrd) {
         while ((me = getmntent(f))) {
                 r = parse_fstab_one(fstab,
                                     me->mnt_fsname, me->mnt_dir, me->mnt_type, me->mnt_opts, me->mnt_passno,
-                                    initrd, /* use_swap_enabled = */ true);
+                                    prefix_sysroot,
+                                    /* accept_root = */ false,
+                                    /* use_swap_enabled = */ true);
                 if (r < 0 && ret >= 0)
                         ret = r;
                 if (arg_sysroot_check && r > 0)
@@ -1282,14 +1293,18 @@ static int add_mounts_from_cmdline(void) {
         /* Handle each entries found in cmdline as a fstab entry. */
 
         FOREACH_ARRAY(m, arg_mounts, arg_n_mounts) {
+                if (m->for_initrd && !in_initrd())
+                        continue;
+
                 r = parse_fstab_one(
                               "/proc/cmdline",
                               m->what,
                               m->where,
                               m->fstype,
                               m->options,
                               /* passno = */ 0,
-                              /* initrd = */ false,
+                              /* prefix_sysroot = */ !m->for_initrd && in_initrd(),
+                              /* accept_root = */ true,
                               /* use_swap_enabled = */ false);
                 if (r < 0 && ret >= 0)
                         ret = r;
@@ -1298,14 +1313,16 @@ static int add_mounts_from_cmdline(void) {
         return ret;
 }
 
-static int add_mounts_from_creds(void) {
+static int add_mounts_from_creds(bool prefix_sysroot) {
         _cleanup_free_ void *b = NULL;
         struct mntent *me;
         int r, ret = 0;
         size_t bs;
 
+        assert(in_initrd() || !prefix_sysroot);
+
         r = read_credential_with_decryption(
-                        in_initrd() ? "fstab.extra.initrd" : "fstab.extra",
+                        in_initrd() && !prefix_sysroot ? "fstab.extra.initrd" : "fstab.extra",
                         &b, &bs);
         if (r <= 0)
                 return r;
@@ -1323,7 +1340,8 @@ static int add_mounts_from_creds(void) {
                                 me->mnt_type,
                                 me->mnt_opts,
                                 me->mnt_passno,
-                                /* initrd = */ false,
+                                /* prefix_sysroot = */ prefix_sysroot,
+                                /* accept_root = */ true,
                                 /* use_swap_enabled = */ true);
                 if (r < 0 && ret >= 0)
                         ret = r;
@@ -1437,21 +1455,21 @@ static int parse_proc_cmdline_item(const char *key, const char *value, void *dat
                 else
                         arg_verity = r;
 
-        } else if (streq(key, "systemd.mount-extra")) {
+        } else if (STR_IN_SET(key, "systemd.mount-extra", "rd.systemd.mount-extra")) {
 
                 if (proc_cmdline_value_missing(key, value))
                         return 0;
 
-                r = mount_array_add(value);
+                r = mount_array_add(startswith(key, "rd."), value);
                 if (r < 0)
                         log_warning("Failed to parse systemd.mount-extra= option, ignoring: %s", value);
 
-        } else if (streq(key, "systemd.swap-extra")) {
+        } else if (STR_IN_SET(key, "systemd.swap-extra", "rd.systemd.swap-extra")) {
 
                 if (proc_cmdline_value_missing(key, value))
                         return 0;
 
-                r = mount_array_add_swap(value);
+                r = mount_array_add_swap(startswith(key, "rd."), value);
                 if (r < 0)
                         log_warning("Failed to parse systemd.swap-extra= option, ignoring: %s", value);
         }
@@ -1517,7 +1535,7 @@ static int run_generator(void) {
         (void) determine_usr();
 
         if (arg_sysroot_check) {
-                r = parse_fstab(/* initrd= */ true);
+                r = parse_fstab(/* prefix_sysroot = */ true);
                 if (r == 0)
                         log_debug("Nothing interesting found, not doing daemon-reload.");
                 if (r > 0)
@@ -1547,13 +1565,13 @@ static int run_generator(void) {
         /* Honour /etc/fstab only when that's enabled */
         if (arg_fstab_enabled) {
                 /* Parse the local /etc/fstab, possibly from the initrd */
-                r = parse_fstab(/* initrd= */ false);
+                r = parse_fstab(/* prefix_sysroot = */ false);
                 if (r < 0 && ret >= 0)
                         ret = r;
 
                 /* If running in the initrd also parse the /etc/fstab from the host */
                 if (in_initrd())
-                        r = parse_fstab(/* initrd= */ true);
+                        r = parse_fstab(/* prefix_sysroot = */ true);
                 else
                         r = generator_enable_remount_fs_service(arg_dest);
                 if (r < 0 && ret >= 0)
@@ -1564,10 +1582,16 @@ static int run_generator(void) {
         if (r < 0 && ret >= 0)
                 ret = r;
 
-        r = add_mounts_from_creds();
+        r = add_mounts_from_creds(/* prefix_sysroot = */ false);
         if (r < 0 && ret >= 0)
                 ret = r;
 
+        if (in_initrd()) {
+                r = add_mounts_from_creds(/* prefix_sysroot = */ true);
+                if (r < 0 && ret >= 0)
+                        ret = r;
+        }
+
         return ret;
 }