Merge pull request #3152 from poettering/aliasfix

Refuse aliases to non-aliasable units in more places

Fixes #2730.

8 files changed, 51 insertions, 51 deletions

diff --git a/man/systemd.automount.xml b/man/systemd.automount.xml
index 93bae2a6dc..a43dc981bd 100644
--- a/man/systemd.automount.xml
+++ b/man/systemd.automount.xml
@@ -66,14 +66,13 @@
     [Install] sections. The automount specific configuration options
     are configured in the [Automount] section.</para>
 
-    <para>Automount units must be named after the automount
-    directories they control. Example: the automount point
-    <filename noindex='true'>/home/lennart</filename> must be
-    configured in a unit file
-    <filename>home-lennart.automount</filename>. For details about the
-    escaping logic used to convert a file system path to a unit name
-    see
-    <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+    <para>Automount units must be named after the automount directories they control. Example: the automount point
+    <filename noindex='true'>/home/lennart</filename> must be configured in a unit file
+    <filename>home-lennart.automount</filename>. For details about the escaping logic used to convert a file system
+    path to a unit name see
+    <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Note that
+    automount units cannot be templated, nor is it possible to add multiple names to an automount unit by creating
+    additional symlinks to its unit file.</para>
 
     <para>For each automount unit file a matching mount unit file (see
     <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
diff --git a/man/systemd.mount.xml b/man/systemd.mount.xml
index f116782b40..bf56a49e58 100644
--- a/man/systemd.mount.xml
+++ b/man/systemd.mount.xml
@@ -82,14 +82,12 @@
     will refuse options that are not listed in
     <filename>/etc/fstab</filename> if it is not run as UID 0.</para>
 
-    <para>Mount units must be named after the mount point directories
-    they control. Example: the mount point
-    <filename noindex='true'>/home/lennart</filename> must be
-    configured in a unit file <filename>home-lennart.mount</filename>.
-    For details about the escaping logic used to convert a file system
-    path to a unit name, see
-    <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
-    Note that mount units cannot be templated.</para>
+    <para>Mount units must be named after the mount point directories they control. Example: the mount point <filename
+    noindex='true'>/home/lennart</filename> must be configured in a unit file <filename>home-lennart.mount</filename>.
+    For details about the escaping logic used to convert a file system path to a unit name, see
+    <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.  Note that mount
+    units cannot be templated, nor is possible to add multiple names to a mount unit by creating additional symlinks to
+    it.</para>
 
     <para>Optionally, a mount unit may be accompanied by an automount
     unit, to allow on-demand or parallelized mounting. See
diff --git a/man/systemd.slice.xml b/man/systemd.slice.xml
index 16247628af..eee98d99ee 100644
--- a/man/systemd.slice.xml
+++ b/man/systemd.slice.xml
@@ -71,6 +71,9 @@
     the root slice <filename>-.slice</filename>.
     </para>
 
+    <para>Note that slice units cannot be templated, nor is possible to add multiple names to a slice unit by creating
+    additional symlinks to it.</para>
+
     <para>By default, service and scope units are placed in
     <filename>system.slice</filename>, virtual machines and containers
     registered with
diff --git a/man/systemd.swap.xml b/man/systemd.swap.xml
index 6fc4c7bf13..cf4e1ba839 100644
--- a/man/systemd.swap.xml
+++ b/man/systemd.swap.xml
@@ -78,13 +78,12 @@
     which configure resource control settings for these processes of the
     unit.</para>
 
-    <para>Swap units must be named after the devices
-    or files they control. Example: the swap device
-    <filename noindex='true'>/dev/sda5</filename> must be configured in a
-    unit file <filename>dev-sda5.swap</filename>. For details about
-    the escaping logic used to convert a file system path to a unit
-    name, see
-    <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+    <para>Swap units must be named after the devices or files they control. Example: the swap device <filename
+    noindex='true'>/dev/sda5</filename> must be configured in a unit file <filename>dev-sda5.swap</filename>. For
+    details about the escaping logic used to convert a file system path to a unit name, see
+    <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Note that swap
+    units cannot be templated, nor is possible to add multiple names to a swap unit by creating additional symlinks to
+    it.</para>
   </refsect1>
 
   <refsect1>
diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index f4b13a7a77..abd47bd237 100644
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -1103,13 +1103,12 @@
       <varlistentry>
         <term><varname>Alias=</varname></term>
 
-        <listitem><para>A space-separated list of additional names
-        this unit shall be installed under. The names listed here must
-        have the same suffix (i.e. type) as the unit file name. This
-        option may be specified more than once, in which case all
-        listed names are used. At installation time,
-        <command>systemctl enable</command> will create symlinks from
-        these names to the unit filename.</para></listitem>
+        <listitem><para>A space-separated list of additional names this unit shall be installed under. The names listed
+        here must have the same suffix (i.e. type) as the unit file name. This option may be specified more than once,
+        in which case all listed names are used. At installation time, <command>systemctl enable</command> will create
+        symlinks from these names to the unit filename. Note that not all unit types support such alias names, and this
+        setting is not supported for them. Specifically, mount, slice, swap, and automount units do not support
+        aliasing.</para></listitem>
       </varlistentry>
 
       <varlistentry>
diff --git a/src/basic/hashmap.c b/src/basic/hashmap.c
index 85b8d812b3..49a0479592 100644
--- a/src/basic/hashmap.c
+++ b/src/basic/hashmap.c
@@ -1773,20 +1773,18 @@ int set_consume(Set *s, void *value) {
 
 int set_put_strdup(Set *s, const char *p) {
         char *c;
-        int r;
 
         assert(s);
         assert(p);
 
+        if (set_contains(s, (char*) p))
+                return 0;
+
         c = strdup(p);
         if (!c)
                 return -ENOMEM;
 
-        r = set_consume(s, c);
-        if (r == -EEXIST)
-                return 0;
-
-        return r;
+        return set_consume(s, c);
 }
 
 int set_put_strdupv(Set *s, char **l) {
diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index c4566f7709..31b995aa6a 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -3427,10 +3427,10 @@ int config_parse_protect_system(
 #define FOLLOW_MAX 8
 
 static int open_follow(char **filename, FILE **_f, Set *names, char **_final) {
+        char *id = NULL;
         unsigned c = 0;
         int fd, r;
         FILE *f;
-        char *id = NULL;
 
         assert(filename);
         assert(*filename);
@@ -3452,7 +3452,6 @@ static int open_follow(char **filename, FILE **_f, Set *names, char **_final) {
                  * the names of this unit, but only if it is a valid
                  * unit name. */
                 name = basename(*filename);
-
                 if (unit_name_is_valid(name, UNIT_NAME_ANY)) {
 
                         id = set_get(names, name);
@@ -3492,6 +3491,7 @@ static int open_follow(char **filename, FILE **_f, Set *names, char **_final) {
 
         *_f = f;
         *_final = id;
+
         return 0;
 }
 
@@ -3552,13 +3552,13 @@ static int merge_by_names(Unit **u, Set *names, const char *id) {
 }
 
 static int load_from_path(Unit *u, const char *path) {
-        int r;
         _cleanup_set_free_free_ Set *symlink_names = NULL;
         _cleanup_fclose_ FILE *f = NULL;
         _cleanup_free_ char *filename = NULL;
         char *id = NULL;
         Unit *merged;
         struct stat st;
+        int r;
 
         assert(u);
         assert(path);
@@ -3597,18 +3597,14 @@ static int load_from_path(Unit *u, const char *path) {
                                 r = -ENOENT;
                         else
                                 r = open_follow(&filename, &f, symlink_names, &id);
+                        if (r >= 0)
+                                break;
+                        filename = mfree(filename);
+                        if (r != -ENOENT)
+                                return r;
 
-                        if (r < 0) {
-                                filename = mfree(filename);
-                                if (r != -ENOENT)
-                                        return r;
-
-                                /* Empty the symlink names for the next run */
-                                set_clear_free(symlink_names);
-                                continue;
-                        }
-
-                        break;
+                        /* Empty the symlink names for the next run */
+                        set_clear_free(symlink_names);
                 }
         }
 
@@ -3616,6 +3612,11 @@ static int load_from_path(Unit *u, const char *path) {
                 /* Hmm, no suitable file found? */
                 return 0;
 
+        if (UNIT_VTABLE(u)->no_alias && set_size(symlink_names) > 1) {
+                log_unit_warning(u, "Unit type of %s does not support alias names, refusing loading via symlink.", u->id);
+                return -ELOOP;
+        }
+
         merged = u;
         r = merge_by_names(&merged, symlink_names, id);
         if (r < 0)
diff --git a/src/core/unit.c b/src/core/unit.c
index 81cd7ee2b8..64466e4fb4 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -720,6 +720,9 @@ int unit_merge(Unit *u, Unit *other) {
         if (!u->instance != !other->instance)
                 return -EINVAL;
 
+        if (UNIT_VTABLE(u)->no_alias) /* Merging only applies to unit names that support aliases */
+                return -EEXIST;
+
         if (other->load_state != UNIT_STUB &&
             other->load_state != UNIT_NOT_FOUND)
                 return -EEXIST;
@@ -776,9 +779,9 @@ int unit_merge(Unit *u, Unit *other) {
 }
 
 int unit_merge_by_name(Unit *u, const char *name) {
+        _cleanup_free_ char *s = NULL;
         Unit *other;
         int r;
-        _cleanup_free_ char *s = NULL;
 
         assert(u);
         assert(name);