core: add support for naming file descriptors passed using socket activation

This adds support for naming file descriptors passed using socket
activation. The names are passed in a new $LISTEN_FDNAMES= environment
variable, that matches the existign $LISTEN_FDS= one and contains a
colon-separated list of names.

This also adds support for naming fds submitted to the per-service fd
store using FDNAME= in the sd_notify() message.

This also adds a new FileDescriptorName= setting for socket unit files
to set the name for fds created by socket units.

This also adds a new call sd_listen_fds_with_names(), that is similar to
sd_listen_fds(), but also returns the names of the fds.

systemd-activate gained the new --fdname= switch to specify a name for
testing socket activation.

This is based on #1247 by Maciej Wereski.

Fixes #1247.

1 files changed, 46 insertions, 2 deletions

diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
index fc2755cb92..b1d4c6b57d 100644
--- a/src/core/load-fragment.c
+++ b/src/core/load-fragment.c
@@ -1475,10 +1475,10 @@ int config_parse_socket_service(
                 void *userdata) {
 
         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_free_ char *p = NULL;
         Socket *s = data;
-        int r;
         Unit *x;
-        _cleanup_free_ char *p = NULL;
+        int r;
 
         assert(filename);
         assert(lvalue);
@@ -1507,6 +1507,50 @@ int config_parse_socket_service(
         return 0;
 }
 
+int config_parse_fdname(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        _cleanup_free_ char *p = NULL;
+        Socket *s = data;
+        int r;
+
+        assert(filename);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (isempty(rvalue)) {
+                s->fdname = mfree(s->fdname);
+                return 0;
+        }
+
+        r = unit_name_printf(UNIT(s), rvalue, &p);
+        if (r < 0) {
+                log_syntax(unit, LOG_ERR, filename, line, r, "Failed to resolve specifiers, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        if (!fdname_is_valid(p)) {
+                log_syntax(unit, LOG_ERR, filename, line, 0, "Invalid file descriptor name, ignoring: %s", p);
+                return 0;
+        }
+
+        free(s->fdname);
+        s->fdname = p;
+        p = NULL;
+
+        return 0;
+}
+
 int config_parse_service_sockets(
                 const char *unit,
                 const char *filename,