"-" prefix for InaccessibleDirectories and ReadOnlyDirectories

TODO

@@ -23,6 +23,9 @@ Bugfixes:
   - make the resulting line the requested number of *characters*, not *bytes*,
   - avoid truncuating multi-byte sequences in the middle.
 
+* When we detect invalid UTF-8, we cant't use it in an error message:
+  log...("Path is not UTF-8 clean, ignoring assignment: %s", rvalue);
+
 * shorten the message to sane length:
 
   Cannot add dependency job for unit display-manager.service, ignoring: Unit display-manager.service failed to load: No such file or directory. See system logs and 'systemctl status display-manager.service' for details.
@@ -285,9 +288,6 @@ Features:
 
 * timedate: have global on/off switches for auto-time (NTP), and auto-timezone that connman can subscribe to.
 
-* Honour "-" prefix for InaccessibleDirectories= and ReadOnlyDirectories= to
-  suppress errors of the specified path doesn't exist
-
 * dev-setup.c: when running in a container, create a tiny stub udev
   database with the systemd tag set for all network interfaces found,
   so that libudev reports them as present, and systemd's .device units

man/systemd.exec.xml

@@ -828,7 +828,15 @@
                                 the empty string is assigned to this
                                 option the specific list is reset, and
                                 all prior assignments have no
-                                effect.</para></listitem>
+                                effect.</para>
+                                <para>Paths in
+                                <varname>ReadOnlyDirectories=</varname>
+                                and
+                                <varname>InaccessibleDirectories=</varname>
+                                may be prefixed with
+                                <literal>-</literal>, in which case
+                                they will be ignored when they don't
+                                exist.</para></listitem>
                         </varlistentry>
 
                         <varlistentry>

src/core/namespace.c

@@ -51,6 +51,7 @@ typedef struct BindMount {
         const char *path;
         MountMode mode;
         bool done;
+        bool ignore;
 } BindMount;
 
 static int append_mounts(BindMount **p, char **strv, MountMode mode) {
@@ -58,6 +59,13 @@ static int append_mounts(BindMount **p, char **strv, MountMode mode) {
 
         STRV_FOREACH(i, strv) {
 
+                (*p)->ignore = false;
+
+                if ((mode == INACCESSIBLE || mode == READONLY) && (*i)[0] == '-') {
+                        (*p)->ignore = true;
+                        (*i)++;
+                }
+
                 if (!path_is_absolute(*i))
                         return -EINVAL;
 
@@ -155,6 +163,8 @@ static int apply_mount(
         r = mount(what, m->path, NULL, MS_BIND|MS_REC, NULL);
         if (r >= 0)
                 log_debug("Successfully mounted %s to %s", what, m->path);
+        else if (m->ignore && errno == ENOENT)
+                r = 0;
 
         return r;
 }
@@ -168,7 +178,7 @@ static int make_read_only(BindMount *m) {
                 return 0;
 
         r = mount(NULL, m->path, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY|MS_REC, NULL);
-        if (r < 0)
+        if (r < 0 && !(m->ignore && errno == ENOENT))
                 return -errno;
 
         return 0;

src/shared/conf-parser.c

@@ -599,6 +599,7 @@ int config_parse_path(const char *unit,
 
         char **s = data;
         char *n;
+        int offset;
 
         assert(filename);
         assert(lvalue);
@@ -611,7 +612,9 @@ int config_parse_path(const char *unit,
                 return 0;
         }
 
-        if (!path_is_absolute(rvalue)) {
+        offset = rvalue[0] == '-' && (streq(lvalue, "InaccessibleDirectories") ||
+                                      streq(lvalue, "ReadOnlyDirectories"));
+        if (!path_is_absolute(rvalue + offset)) {
                 log_syntax(unit, LOG_ERR, filename, line, EINVAL,
                            "Not an absolute path, ignoring: %s", rvalue);
                 return 0;
@@ -713,6 +716,7 @@ int config_parse_path_strv(const char *unit,
 
         FOREACH_WORD_QUOTED(w, l, rvalue, state) {
                 _cleanup_free_ char *n;
+                int offset;
 
                 n = strndup(w, l);
                 if (!n)
@@ -724,7 +728,9 @@ int config_parse_path_strv(const char *unit,
                         continue;
                 }
 
-                if (!path_is_absolute(n)) {
+                offset = n[0] == '-' && (streq(lvalue, "InaccessibleDirectories") ||
+                                         streq(lvalue, "ReadOnlyDirectories"));
+                if (!path_is_absolute(n + offset)) {
                         log_syntax(unit, LOG_ERR, filename, line, EINVAL,
                                    "Not an absolute path, ignoring: %s", rvalue);
                         continue;