From 3f4082478351da51d7c4c8907ec691238a384313 Mon Sep 17 00:00:00 2001

From: Michal Sekletar <msekleta@redhat.com>

Date: Wed, 22 Nov 2023 20:40:31 +0100

Subject: [PATCH] Revert "fstab-generator: Chase symlinks where possible

 (#6293)"

This reverts commit a4c51f1bb38f272fb9c3dbaa33f1f383639ce345.

Resolves: RHEL-17164

---

 man/systemd-fstab-generator.xml       |  8 -----

 man/systemd.mount.xml                 |  5 ++--

 src/fstab-generator/fstab-generator.c | 42 +++++----------------------

 3 files changed, 10 insertions(+), 45 deletions(-)

diff --git a/man/systemd-fstab-generator.xml b/man/systemd-fstab-generator.xml

index 6f45c680cc..bdc2dc1d0e 100644

--- a/man/systemd-fstab-generator.xml

+++ b/man/systemd-fstab-generator.xml

@@ -71,14 +71,6 @@

     for more information about special <filename>/etc/fstab</filename>

     mount options this generator understands.</para>

-    <para>One special topic is handling of symbolic links.  Historical init

-    implementations supported symlinks in <filename>/etc/fstab</filename>.

-    Because mount units will refuse mounts where the target is a symbolic link,

-    this generator will resolve any symlinks as far as possible when processing

-    <filename>/etc/fstab</filename> in order to enhance backwards compatibility.

-    If a symlink target does not exist at the time that this generator runs, it

-    is assumed that the symlink target is the final target of the mount.</para>

-

     <para><filename>systemd-fstab-generator</filename> implements

     <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>

   </refsect1>

diff --git a/man/systemd.mount.xml b/man/systemd.mount.xml

index 5021db5584..1590c44cec 100644

--- a/man/systemd.mount.xml

+++ b/man/systemd.mount.xml

@@ -295,9 +295,8 @@

       <varlistentry>

         <term><varname>Where=</varname></term>

-        <listitem><para>Takes an absolute path of a directory for the

-        mount point; in particular, the destination cannot be a symbolic

-        link.  If the mount point does not exist at the time of

+        <listitem><para>Takes an absolute path of a directory of the

+        mount point. If the mount point does not exist at the time of

         mounting, it is created. This string must be reflected in the

         unit filename. (See above.) This option is

         mandatory.</para></listitem>

diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c

index 91603b08f4..23b5457e43 100644

--- a/src/fstab-generator/fstab-generator.c

+++ b/src/fstab-generator/fstab-generator.c

@@ -240,7 +240,6 @@ static int write_idle_timeout(FILE *f, const char *where, const char *opts) {

 static int add_mount(

                 const char *what,

                 const char *where,

-                const char *original_where,

                 const char *fstype,

                 const char *opts,

                 int passno,

@@ -328,14 +327,12 @@ static int add_mount(

         }

         fprintf(f,

-                 "\n"

+                "\n"

                 "[Mount]\n"

-                "What=%s\n",

-                 what);

-

-        if (original_where)

-                fprintf(f, "# Canonicalized from %s\n", original_where);

-        fprintf(f, "Where=%s\n", where);

+                "What=%s\n"

+                "Where=%s\n",

+                what,

+                where);

         if (!isempty(fstype) && !streq(fstype, "auto"))

                 fprintf(f, "Type=%s\n", fstype);

@@ -439,7 +436,7 @@ static int parse_fstab(bool initrd) {

         }

         while ((me = getmntent(f))) {

-                _cleanup_free_ char *where = NULL, *what = NULL, *canonical_where = NULL;

+                _cleanup_free_ char *where = NULL, *what = NULL;

                 bool noauto, nofail;

                 int k;

@@ -459,28 +456,8 @@ static int parse_fstab(bool initrd) {

                 if (!where)

                         return log_oom();

-                if (is_path(where)) {

+                if (is_path(where))

                         path_kill_slashes(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.

-                         */

-                        r = chase_symlinks(where, initrd ? "/sysroot" : NULL,

-                                           CHASE_PREFIX_ROOT | CHASE_NONEXISTENT,

-                                           &canonical_where);

-                        if (r < 0)

-                                /* In this case for now we continue on as if it wasn't a symlink */

-                                log_warning_errno(r, "Failed to read symlink target for %s: %m", where);

-                        else {

-                                if (streq(canonical_where, where))

-                                        canonical_where = mfree(canonical_where);

-                                else

-                                        log_debug("Canonicalized what=%s where=%s to %s",

-                                                  what, where, canonical_where);

-                        }

-                }

                 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");

@@ -505,8 +482,7 @@ static int parse_fstab(bool initrd) {

                                 post = SPECIAL_LOCAL_FS_TARGET;

                         k = add_mount(what,

-                                      canonical_where ?: where,

-                                      canonical_where ? where: NULL,

+                                      where,

                                       me->mnt_type,

                                       me->mnt_opts,

                                       me->mnt_passno,

@@ -550,7 +526,6 @@ static int add_sysroot_mount(void) {

         log_debug("Found entry what=%s where=/sysroot type=%s", what, strna(arg_root_fstype));

         return add_mount(what,

                          "/sysroot",

-                         NULL,

                          arg_root_fstype,

                          opts,

                          1,

@@ -608,7 +583,6 @@ static int add_sysroot_usr_mount(void) {

         log_debug("Found entry what=%s where=/sysroot/usr type=%s", what, strna(arg_usr_fstype));

         return add_mount(what,

                          "/sysroot/usr",

-                         NULL,

                          arg_usr_fstype,

                          opts,

                          1,