fix(editor): avoid Ctrl-Z hang on the editor child, add SIGUSR1 escape

The upstream signal reset in launch_editor set SIGTSTP back to SIG_DFL in
the child, letting Ctrl-Z (or vim's :stop) stop the editor. GLib's
g_child_watch uses waitpid(WNOHANG) without WUNTRACED, so a STOPPED
editor never wakes the watch and the app freezes until killed externally.
Other TUI chat clients carry this open problem for years (see
weechat/weechat#985, open since 2017); shells solve it with full job
control (setpgid + tcsetpgrp + WUNTRACED), which is heavy for our use
case.

Drop just the SIGTSTP reset. SIGINT and SIGPIPE are still set to SIG_DFL
— Neovim's libuv needs SIGINT-as-default to recognise an interactive
terminal (per upstream commit dd76f9087). SIGTSTP stays inherited as
SIG_IGN from profanity's _init, so Ctrl-Z and vim's :stop become no-ops
inside /editor. Losing vim's :stop during message composition is an
acceptable trade for not freezing the whole app.

As a universal escape hatch for any other "hung editor" scenario
(looping $EDITOR, corrupted tty, anything we cannot detect), install a
SIGUSR1 handler via g_unix_signal_add that sends SIGTERM to the editor
child via editor_emergency_kill(). The existing g_child_watch then
dispatches the normal exit callback, ui_resume runs, and the user is
back in profanity. Recovery from another terminal: `pkill -USR1
profanity`.

src/event/server_events.c

@@ -341,7 +341,7 @@ sv_ev_room_message(ProfMessage* message)
         status_bar_active(num, WIN_MUC, mucwin->roomjid);
 
         if ((g_strcmp0(mynick, message->from_jid->resourcepart) != 0) && (prefs_get_boolean(PREF_BEEP))) {
-            beep();
+            ui_beep();
         }
 
         // not currently on groupchat window
@@ -349,7 +349,7 @@ sv_ev_room_message(ProfMessage* message)
         status_bar_new(num, WIN_MUC, mucwin->roomjid);
 
         if ((g_strcmp0(mynick, message->from_jid->resourcepart) != 0) && (prefs_get_boolean(PREF_FLASH))) {
-            flash();
+            ui_flash();
         }
 
         cons_show_incoming_room_message(message->from_jid->resourcepart, mucwin->roomjid, num, mention, triggers, mucwin->unread, window);

src/profanity.c

@@ -20,6 +20,7 @@
 #include <string.h>
 
 #include <glib.h>
+#include <glib-unix.h>
 
 #include "profanity.h"
 #include "common.h"
@@ -182,6 +183,16 @@ sigterm_handler(int sig)
     force_quit = TRUE;
 }
 
+// Universal "I'm stuck in the editor" escape hatch. Dispatched in the main
+// loop by GLib (g_unix_signal_add), so it is safe to call into editor.c
+// directly. Trigger from another terminal: `pkill -USR1 profanity`.
+static gboolean
+_emergency_resume_handler(gpointer data)
+{
+    editor_emergency_kill();
+    return G_SOURCE_CONTINUE;
+}
+
 static void
 _init(char* log_level, char* config_file, char* log_file, char* theme_name)
 {
@@ -193,6 +204,7 @@ _init(char* log_level, char* config_file, char* log_file, char* theme_name)
     signal(SIGWINCH, ui_sigwinch_handler);
     signal(SIGTERM, sigterm_handler);
     signal(SIGHUP, sigterm_handler);
+    g_unix_signal_add(SIGUSR1, _emergency_resume_handler, NULL);
     if (pthread_mutex_init(&lock, NULL) != 0) {
         log_error("Mutex init failed");
         exit(1);

src/tools/editor.c

@@ -32,9 +32,22 @@ typedef struct EditorContext
     void* user_data;
 } EditorContext;
 
+// Set TRUE for the lifetime of an editor session (from launch_editor up to
+// _editor_exit_cb / fork-error cleanup). The async editor model lost the old
+// editor_task.active check from the pthread implementation; without this
+// guard a second launch_editor (e.g. via a plugin dispatched through
+// g_main_context_iteration) would call ui_suspend again and fork a second
+// editor that fights the first one for the terminal, then prematurely
+// ui_resume when either exits.
+static gboolean editor_active = FALSE;
+static pid_t editor_pid = 0;
+
 static void
 _editor_exit_cb(GPid pid, gint status, gpointer data)
 {
+    editor_active = FALSE;
+    editor_pid = 0;
+
     EditorContext* ctx = data;
     gchar* contents = NULL;
     GError* error = NULL;
@@ -70,6 +83,11 @@ _editor_exit_cb(GPid pid, gint status, gpointer data)
 gboolean
 launch_editor(gchar* initial_content, void (*callback)(gchar* content, void* data), void* user_data)
 {
+    if (editor_active) {
+        cons_show_error("An editor session is already active.");
+        return TRUE;
+    }
+
     auto_gchar gchar* filename = NULL;
     auto_gerror GError* glib_error = NULL;
     const char* jid = connection_get_barejid();
@@ -118,6 +136,7 @@ launch_editor(gchar* initial_content, void (*callback)(gchar* content, void* dat
     ctx->callback = callback;
     ctx->user_data = user_data;
 
+    editor_active = TRUE;
     ui_suspend();
 
     // Force GLib to install its SIGCHLD handler before forking. Creating a
@@ -129,6 +148,7 @@ launch_editor(gchar* initial_content, void (*callback)(gchar* content, void* dat
     pid_t pid = fork();
     if (pid == -1) {
         log_error("[Editor] Failed to fork: %s", strerror(errno));
+        editor_active = FALSE;
         ui_resume();
         ui_resize();
         cons_show_error("Failed to start editor: %s", strerror(errno));
@@ -139,9 +159,11 @@ launch_editor(gchar* initial_content, void (*callback)(gchar* content, void* dat
     } else if (pid == 0) {
         // Child process: Inherits TTY from parent
 
-        // Reset signal handlers that profanity sets so the editor doesn't inherit them
+        // SIGTSTP intentionally NOT reset: keeping SIG_IGN inherited via
+        // fork+exec avoids hanging on a STOPPED editor (g_child_watch lacks
+        // WUNTRACED). Cost: vim's :stop is a no-op in /editor. See
+        // editor_emergency_kill for other hung-editor scenarios.
         signal(SIGINT, SIG_DFL);
-        signal(SIGTSTP, SIG_DFL);
         signal(SIGPIPE, SIG_DFL);
 
         if (editor_argv && editor_argv[0]) {
@@ -151,7 +173,20 @@ launch_editor(gchar* initial_content, void (*callback)(gchar* content, void* dat
     }
 
     // Parent process: Watch the child asynchronously
+    editor_pid = pid;
     g_child_watch_add((GPid)pid, _editor_exit_cb, ctx);
     g_strfreev(editor_argv);
     return FALSE;
 }
+
+void
+editor_emergency_kill(void)
+{
+    if (!editor_active || editor_pid <= 0) {
+        return;
+    }
+    log_warning("[Editor] emergency resume: sending SIGTERM to editor pid %d", editor_pid);
+    kill(editor_pid, SIGTERM);
+    // g_child_watch dispatches _editor_exit_cb when the child exits, which
+    // already restores the UI — no further action required here.
+}

src/tools/editor.h

@@ -16,4 +16,9 @@
 
 gboolean launch_editor(gchar* initial_content, void (*callback)(gchar* content, void* data), void* user_data);
 
+// Universal escape hatch: if an editor session is active, send SIGTERM to the
+// child. The existing g_child_watch fires _editor_exit_cb on exit, which
+// already restores the UI. Wired to SIGUSR1 in profanity.c.
+void editor_emergency_kill(void);
+
 #endif

src/ui/chatwin.c

@@ -327,7 +327,7 @@ chatwin_incoming_msg(ProfChatWin* chatwin, ProfMessage* message, gboolean win_cr
             cons_show_incoming_message(display_name, num, chatwin->unread, window);
 
             if (prefs_get_boolean(PREF_FLASH)) {
-                flash();
+                ui_flash();
             }
 
             chatwin->unread++;
@@ -364,7 +364,7 @@ chatwin_incoming_msg(ProfChatWin* chatwin, ProfMessage* message, gboolean win_cr
         wins_add_quotes_ac(window, message->plain, FALSE);
 
         if (prefs_get_boolean(PREF_BEEP)) {
-            beep();
+            ui_beep();
         }
     }
 

src/ui/core.c

@@ -54,6 +54,7 @@
 
 static int inp_size;
 static gboolean perform_resize = FALSE;
+static gboolean ui_suspended = FALSE;
 static GTimer* ui_idle_time;
 static WINDOW* main_scr;
 
@@ -63,6 +64,16 @@ static Display* display;
 
 static void _ui_draw_term_title(void);
 
+// Skip drawing while an external editor is active (ui_suspended) or after the
+// screen has been closed (endwin). The flag is authoritative and does not rely
+// on isendwin() staying TRUE, which a stray doupdate() during the session could
+// otherwise clear.
+static gboolean
+_ui_redraw_suspended(void)
+{
+    return ui_suspended || isendwin();
+}
+
 static void
 _ui_close(void)
 {
@@ -120,8 +131,7 @@ ui_sigwinch_handler(int sig)
 void
 ui_update(void)
 {
-    // UI is suspended
-    if (isendwin()) {
+    if (_ui_redraw_suspended()) {
         return;
     }
 
@@ -138,7 +148,7 @@ ui_update(void)
     title_bar_update_virtual();
     status_bar_draw();
     inp_put_back();
-    doupdate();
+    prof_doupdate();
 
     if (perform_resize) {
         perform_resize = FALSE;
@@ -180,21 +190,48 @@ void
 ui_suspend(void)
 {
     inp_suspend();
+    // Flush before flipping the flag (prof_doupdate skips while suspended).
+    prof_doupdate();
+    ui_suspended = TRUE;
     endwin();
 }
 
 void
 ui_resume(void)
 {
+    ui_suspended = FALSE;
     refresh();
     inp_resume();
 }
 
+void
+ui_beep(void)
+{
+    if (!isendwin()) {
+        beep();
+    }
+}
+
+void
+ui_flash(void)
+{
+    if (!isendwin()) {
+        flash();
+    }
+}
+
+void
+prof_doupdate(void)
+{
+    if (!_ui_redraw_suspended()) {
+        doupdate();
+    }
+}
+
 void
 ui_resize(void)
 {
-    // UI is suspended
-    if (isendwin()) {
+    if (_ui_redraw_suspended()) {
         return;
     }
 
@@ -216,8 +253,7 @@ ui_resize(void)
 void
 ui_redraw(void)
 {
-    // UI is suspended
-    if (isendwin()) {
+    if (_ui_redraw_suspended()) {
         return;
     }
 

src/ui/inputwin.c

@@ -182,7 +182,13 @@ inp_readline(void)
 {
     // UI is suspended
     if (is_suspended || isendwin()) {
+        // Mirror the normal-path unlock/sleep/lock so worker threads
+        // (http_upload / http_download / ai_client) can acquire `lock`
+        // during the editor session — otherwise the main thread holds
+        // it continuously and every in-flight transfer freezes.
+        pthread_mutex_unlock(&lock);
         g_usleep(100000); // 100ms
+        pthread_mutex_lock(&lock);
         return NULL;
     }
 
@@ -311,11 +317,15 @@ inp_get_line(void)
     werase(inp_win);
     wmove(inp_win, 0, 0);
     _inp_win_update_virtual();
-    doupdate();
+    prof_doupdate();
     char* line = NULL;
     while (!line) {
         line = inp_readline();
         ui_update();
+        // Let GLib sources (notably the editor child watch) dispatch so
+        // ui_resume can run if the prompt was raised mid-editor-session.
+        while (g_main_context_iteration(NULL, FALSE))
+            ;
     }
     status_bar_clear_prompt();
     return line;
@@ -338,12 +348,16 @@ inp_get_password(void)
     werase(inp_win);
     wmove(inp_win, 0, 0);
     _inp_win_update_virtual();
-    doupdate();
+    prof_doupdate();
     char* password = NULL;
     get_password = TRUE;
     while (!password) {
         password = inp_readline();
         ui_update();
+        // Let GLib sources (notably the editor child watch) dispatch so
+        // ui_resume can run if the prompt was raised mid-editor-session.
+        while (g_main_context_iteration(NULL, FALSE))
+            ;
     }
     get_password = FALSE;
     status_bar_clear_prompt();
@@ -459,7 +473,7 @@ _inp_write(char* line, int offset)
     _inp_win_handle_scroll();
 
     _inp_win_update_virtual();
-    doupdate();
+    prof_doupdate();
 }
 
 static int

src/ui/privwin.c

@@ -57,7 +57,7 @@ privwin_incoming_msg(ProfPrivateWin* privatewin, ProfMessage* message)
         privatewin->unread++;
 
         if (prefs_get_boolean(PREF_FLASH)) {
-            flash();
+            ui_flash();
         }
     }
 
@@ -65,7 +65,7 @@ privwin_incoming_msg(ProfPrivateWin* privatewin, ProfMessage* message)
     wins_add_quotes_ac(window, message->plain, TRUE);
 
     if (prefs_get_boolean(PREF_BEEP)) {
-        beep();
+        ui_beep();
     }
 
     if (notify) {

src/ui/ui.h

@@ -43,6 +43,10 @@ void ui_load_colours(void);
 void ui_update(void);
 void ui_redraw(void);
 void ui_resize(void);
+// Centralised physical-paint primitive: flushes the virtual screen unless the
+// UI is suspended (external editor active) or the screen has been closed. Use
+// this instead of raw doupdate() in any path reachable while suspended.
+void prof_doupdate(void);
 void ui_focus_win(ProfWin* window);
 void ui_sigwinch_handler(int sig);
 void ui_handle_otr_error(const char* const barejid, const char* const message);
@@ -84,6 +88,8 @@ void ui_handle_recipient_error(const char* const recipient, const char* const er
 void ui_handle_error(const char* const err_msg);
 void ui_clear_win_title(void);
 void ui_goodbye_title(void);
+void ui_beep(void);
+void ui_flash(void);
 void ui_handle_room_configuration_form_error(const char* const roomjid, const char* const message);
 void ui_handle_room_config_submit_result(const char* const roomjid);
 void ui_handle_room_config_submit_result_error(const char* const roomjid, const char* const message);

tests/unittests/ui/stub_ui.c

@@ -85,6 +85,10 @@ void
 ui_resize(void)
 {
 }
+void
+prof_doupdate(void)
+{
+}
 
 void
 ui_focus_win(ProfWin* win)
@@ -1475,3 +1479,13 @@ ui_is_suspended(void)
 {
     return FALSE;
 }
+
+void
+ui_beep(void)
+{
+}
+
+void
+ui_flash(void)
+{
+}