shared/wall: several cleanups

Follow-up for 53c0397b1dbc95f144d9a551c2086d132933e8ce

* Split do_wall into wall_utmp and wall_logind
* Don't pass unused arguments
* Add missing asserts
* Modernize error handling
* Don't do anything if neither utmp nor logind is enabled

2 files changed, 73 insertions, 49 deletions

diff --git a/src/shared/wall.c b/src/shared/wall.c
index e2efd96d37..9fdde59eda 100644
--- a/src/shared/wall.c
+++ b/src/shared/wall.c
@@ -17,6 +17,8 @@
 #include "utmp-wtmp.h"
 #include "wall.h"
 
+#if ENABLE_UTMP || ENABLE_LOGIND
+
 #define TIMEOUT_USEC (50 * USEC_PER_MSEC)
 
 static int write_to_terminal(const char *tty, const char *message) {
@@ -35,95 +37,90 @@ static int write_to_terminal(const char *tty, const char *message) {
 }
 
 #if ENABLE_UTMP
-static int do_wall(
+static int wall_utmp(
         const char *message,
-        const char *username,
-        const char *origin_tty,
         bool (*match_tty)(const char *tty, bool is_local, void *userdata),
         void *userdata) {
 
         _unused_ _cleanup_(utxent_cleanup) bool utmpx = false;
         struct utmpx *u;
-        int r;
+        int r = 0;
 
-        utmpx = utxent_start();
+        assert(message);
 
-        r = 0;
+        utmpx = utxent_start();
 
         while ((u = getutxent())) {
-                _cleanup_free_ char *buf = NULL;
-                const char *path;
-                int q;
+                _cleanup_free_ char *p = NULL;
+                const char *tty_path;
+                bool is_local;
 
-                if (u->ut_type != USER_PROCESS || u->ut_user[0] == 0)
+                if (u->ut_type != USER_PROCESS || isempty(u->ut_user))
                         continue;
 
                 /* This access is fine, because strlen("/dev/") < 32 (UT_LINESIZE) */
                 if (path_startswith(u->ut_line, "/dev/"))
-                        path = u->ut_line;
+                        tty_path = u->ut_line;
                 else {
-                        if (asprintf(&buf, "/dev/%.*s", (int) sizeof(u->ut_line), u->ut_line) < 0)
+                        if (asprintf(&p, "/dev/%.*s", (int) sizeof(u->ut_line), u->ut_line) < 0)
                                 return -ENOMEM;
-                        path = buf;
+
+                        tty_path = p;
                 }
 
-                /* It seems that the address field is always set for remote logins.
-                 * For local logins and other local entries, we get [0,0,0,0]. */
-                bool is_local = memeqzero(u->ut_addr_v6, sizeof(u->ut_addr_v6));
+                /* It seems that the address field is always set for remote logins. For local logins and
+                 * other local entries, we get [0,0,0,0]. */
+                is_local = eqzero(u->ut_addr_v6);
 
-                if (!match_tty || match_tty(path, is_local, userdata)) {
-                        q = write_to_terminal(path, message);
-                        if (q < 0)
-                                r = q;
-                }
+                if (!match_tty || match_tty(tty_path, is_local, userdata))
+                        RET_GATHER(r, write_to_terminal(tty_path, message));
         }
 
         return r;
 }
+#endif
 
-#else
-
-static int do_wall(
+#if ENABLE_LOGIND
+static int wall_logind(
         const char *message,
-        const char *username,
-        const char *origin_tty,
         bool (*match_tty)(const char *tty, bool is_local, void *userdata),
         void *userdata) {
 
-        int r;
         _cleanup_strv_free_ char **sessions = NULL;
+        int r;
+
+        assert(message);
 
         r = sd_get_sessions(&sessions);
-        if (r < 0)
+        if (r <= 0)
                 return r;
 
+        r = 0;
+
         STRV_FOREACH(s, sessions) {
-                _cleanup_free_ char *path = NULL, *tty = NULL, *rhost = NULL;
+                _cleanup_free_ char *tty_path = NULL, *tty = NULL, *rhost = NULL;
+                bool is_local;
                 int q;
 
                 q = sd_session_get_tty(*s, &tty);
-                if (q < 0) {
-                        if (q != -ENXIO && q != -ENODATA)
-                                r = q;
+                if (IN_SET(q, -ENXIO, -ENODATA))
                         continue;
-                }
+                if (q < 0)
+                        return RET_GATHER(r, q);
 
-                path = strjoin("/dev/", tty);
-                if (!path)
+                tty_path = strjoin("/dev/", tty);
+                if (!tty_path)
                         return -ENOMEM;
 
                 (void) sd_session_get_remote_host(*s, &rhost);
-                bool is_local = !rhost;
+                is_local = !rhost;
 
-                if (!match_tty || match_tty(path, is_local, userdata)) {
-                        q = write_to_terminal(path, message);
-                        if (q < 0)
-                                r = q;
-                }
+                if (!match_tty || match_tty(tty_path, is_local, userdata))
+                        RET_GATHER(r, write_to_terminal(tty_path, message));
         }
+
         return r;
 }
-
 #endif
 
 int wall(
@@ -133,15 +130,20 @@ int wall(
         bool (*match_tty)(const char *tty, bool is_local, void *userdata),
         void *userdata) {
 
-        _cleanup_free_ char *text = NULL, *hn = NULL, *un = NULL, *stdin_tty = NULL;
+        _cleanup_free_ char *text = NULL, *hostname = NULL, *username_alloc = NULL, *stdin_tty = NULL;
 
-        hn = gethostname_malloc();
-        if (!hn)
+        assert(message);
+
+        hostname = gethostname_malloc();
+        if (!hostname)
                 return -ENOMEM;
+
         if (!username) {
-                un = getlogname_malloc();
-                if (!un)
+                username_alloc = getlogname_malloc();
+                if (!username_alloc)
                         return -ENOMEM;
+
+                username = username_alloc;
         }
 
         if (!origin_tty) {
@@ -153,11 +155,17 @@ int wall(
                      "\r\n"
                      "Broadcast message from %s@%s%s%s (%s):\r\n\r\n"
                      "%s\r\n\r\n",
-                     un ?: username, hn,
+                     username, hostname,
                      origin_tty ? " on " : "", strempty(origin_tty),
                      FORMAT_TIMESTAMP(now(CLOCK_REALTIME)),
                      message) < 0)
                 return -ENOMEM;
 
-        return do_wall(text, username, origin_tty, match_tty, userdata);
+#if ENABLE_UTMP
+        return wall_utmp(text, match_tty, userdata);
+#elif ENABLE_LOGIND
+        return wall_logind(text, match_tty, userdata);
+#endif
 }
+
+#endif
diff --git a/src/shared/wall.h b/src/shared/wall.h
index 4423c39404..29642778c7 100644
--- a/src/shared/wall.h
+++ b/src/shared/wall.h
@@ -3,9 +3,25 @@
 
 #include <stdbool.h>
 
+#if ENABLE_UTMP || ENABLE_LOGIND
+
 int wall(
         const char *message,
         const char *username,
         const char *origin_tty,
         bool (*match_tty)(const char *tty, bool is_local, void *userdata),
         void *userdata);
+
+#else
+
+static inline int wall(
+        const char *message,
+        const char *username,
+        const char *origin_tty,
+        bool (*match_tty)(const char *tty, bool is_local, void *userdata),
+        void *userdata) {
+
+        return 0;
+}
+
+#endif