sd-daemon: add sd_pid_notifyf_with_fds()

I guess it was only a question of time until we need to add the final
frontier of notification functions: one that combines the features of
all the others:

1. specifiying a source PID
2. taking a list of fds to send along
3. accepting a format string for the status string

Hence, let's add it.

2 files changed, 31 insertions, 0 deletions

diff --git a/src/libsystemd/libsystemd.sym b/src/libsystemd/libsystemd.sym
index 53db234a0c..76fa1e0e32 100644
--- a/src/libsystemd/libsystemd.sym
+++ b/src/libsystemd/libsystemd.sym
@@ -818,4 +818,5 @@ global:
         sd_session_get_username;
         sd_session_get_start_time;
         sd_uid_get_login_time;
+        sd_pid_notifyf_with_fds;
 } LIBSYSTEMD_253;
diff --git a/src/libsystemd/sd-daemon/sd-daemon.c b/src/libsystemd/sd-daemon/sd-daemon.c
index f2f295d6e4..eec6fb64ef 100644
--- a/src/libsystemd/sd-daemon/sd-daemon.c
+++ b/src/libsystemd/sd-daemon/sd-daemon.c
@@ -667,6 +667,36 @@ _public_ int sd_notifyf(int unset_environment, const char *format, ...) {
         return sd_pid_notify(0, unset_environment, p);
 }
 
+int sd_pid_notifyf_with_fds(
+                pid_t pid,
+                int unset_environment,
+                const int *fds, size_t n_fds,
+                const char *format, ...) {
+
+        _cleanup_free_ char *p = NULL;
+        int r;
+
+        /* Paranoia check: we traditionally used 'unsigned' as array size, but we nowadays more correctly use
+         * 'size_t'. sd_pid_notifyf_with_fds() and sd_pid_notify_with_fds() are from different eras, hence
+         * differ in this. Let's catch resulting incompatibilites early, even though they are pretty much
+         * theoretic only */
+        if (n_fds > UINT_MAX)
+                return -E2BIG;
+
+        if (format) {
+                va_list ap;
+
+                va_start(ap, format);
+                r = vasprintf(&p, format, ap);
+                va_end(ap);
+
+                if (r < 0 || !p)
+                        return -ENOMEM;
+        }
+
+        return sd_pid_notify_with_fds(pid, unset_environment, p, fds, n_fds);
+}
+
 _public_ int sd_booted(void) {
         /* We test whether the runtime unit file directory has been
          * created. This takes place in mount-setup.c, so is