shared/utmp-wtmp: add parameter for origin tty and callback userdata

Instead of looking up the tty from STDIN, let utmp_wall() take an argument
to specify an origin tty for the wall message. Only if that argument is
NULL do the STDIN lookup.

Also add an void *userdata argument that is handed back to the callback
function.

src/shared/utmp-wtmp.c

@@ -347,8 +347,14 @@ static int write_to_terminal(const char *tty, const char *message) {
         return 0;
 }
 
-int utmp_wall(const char *message, const char *username, bool (*match_tty)(const char *tty)) {
-        _cleanup_free_ char *text = NULL, *hn = NULL, *un = NULL, *tty = NULL;
+int utmp_wall(
+        const char *message,
+        const char *username,
+        const char *origin_tty,
+        bool (*match_tty)(const char *tty, void *userdata),
+        void *userdata) {
+
+        _cleanup_free_ char *text = NULL, *hn = NULL, *un = NULL, *stdin_tty = NULL;
         char date[FORMAT_TIMESTAMP_MAX];
         struct utmpx *u;
         int r;
@@ -362,14 +368,17 @@ int utmp_wall(const char *message, const char *username, bool (*match_tty)(const
                         return -ENOMEM;
         }
 
-        getttyname_harder(STDIN_FILENO, &tty);
+        if (!origin_tty) {
+                getttyname_harder(STDIN_FILENO, &stdin_tty);
+                origin_tty = stdin_tty;
+        }
 
         if (asprintf(&text,
                      "\a\r\n"
                      "Broadcast message from %s@%s%s%s (%s):\r\n\r\n"
                      "%s\r\n\r\n",
                      un ?: username, hn,
-                     tty ? " on " : "", strempty(tty),
+                     origin_tty ? " on " : "", strempty(origin_tty),
                      format_timestamp(date, sizeof(date), now(CLOCK_REALTIME)),
                      message) < 0)
                 return -ENOMEM;
@@ -396,7 +405,7 @@ int utmp_wall(const char *message, const char *username, bool (*match_tty)(const
                         path = buf;
                 }
 
-                if (!match_tty || match_tty(path)) {
+                if (!match_tty || match_tty(path, userdata)) {
                         q = write_to_terminal(path, text);
                         if (q < 0)
                                 r = q;

src/shared/utmp-wtmp.h

@@ -33,7 +33,12 @@ int utmp_put_runlevel(int runlevel, int previous);
 int utmp_put_dead_process(const char *id, pid_t pid, int code, int status);
 int utmp_put_init_process(const char *id, pid_t pid, pid_t sid, const char *line);
 
-int utmp_wall(const char *message, const char *username, bool (*match_tty)(const char *tty));
+int utmp_wall(
+        const char *message,
+        const char *username,
+        const char *origin_tty,
+        bool (*match_tty)(const char *tty, void *userdata),
+        void *userdata);
 
 #else /* HAVE_UTMP */
 
@@ -55,8 +60,12 @@ static inline int utmp_put_dead_process(const char *id, pid_t pid, int code, int
 static inline int utmp_put_init_process(const char *id, pid_t pid, pid_t sid, const char *line) {
         return 0;
 }
-static inline int utmp_wall(const char *message, const char *username,
-                bool (*match_tty)(const char *tty)) {
+static inline int utmp_wall(
+                const char *message,
+                const char *username,
+                const char *origin_tty,
+                bool (*match_tty)(const char *tty, void *userdata),
+                void *userdata);
         return 0;
 }