i3 - improved tiling WM

Authentication in different process

Patch status: needinfo

Patch by Philippe Virouleau

Long description:

Add the possibility to buffer keystrokes when a process is running authentication
Fix #1090.

To apply this patch, use:
curl http://cr.i3wm.org/patch/298/raw.patch | git am

b/i3lock.c

15 
@@ -63,6 +63,18 @@ cairo_surface_t *img = NULL;
16 
 bool tile = false;
17 
 bool ignore_empty_password = false;
18
19 
+typedef struct ringbuffer_t {
20 
+    int head;
21 
+    int tail;
22 
+    int size;
23 
+    xcb_generic_event_t *buf[512];
24 
+} ringbuffer_t;
25 
+/* Size of the ringbuffer */
26 
+const int ringbuffer_max = 512;
27 
+
28 
+/* Ring buffer where keystrokes are stored during authentication */
29 
+static ringbuffer_t buffered_events = { 0, 0, 0 };
30 
+
31 
 /* isutf, u8_dec © 2005 Jeff Bezanson, public domain */
32 
 #define isutf(c) (((c) & 0xC0) != 0x80)
33
34 
@@ -75,6 +87,39 @@ void u8_dec(char *s, int *i) {
35 
 }
36
37 
 /*
38 
+ * Add an event to the ring buffer.
39 
+ *
40 
+ * Return 0 if the event was added, 1 if there was an error (no space available
41 
+ * or null buffer).
42 
+ *
43 
+ */
44 
+static int ringbuffer_add(ringbuffer_t *bufring, xcb_generic_event_t *event) {
45 
+    if (bufring && bufring->size < ringbuffer_max) {
46 
+        bufring->buf[bufring->head++] = event;
47 
+        bufring->head %= ringbuffer_max;
48 
+        bufring->size++;
49 
+        return 0;
50 
+    }
51 
+    return 1;
52 
+}
53 
+
54 
+/*
55 
+ * Remove an event from the ring buffer.
56 
+ *
57 
+ * Return null if there was an error (empty or null buffer).
58 
+ *
59 
+ */
60 
+static xcb_generic_event_t *ringbuffer_remove(ringbuffer_t *bufring) {
61 
+    xcb_generic_event_t *ret_val = NULL;
62 
+    if (bufring && bufring->size > 0) {
63 
+        ret_val = bufring->buf[bufring->tail++];
64 
+        bufring->tail %= ringbuffer_max;
65 
+        bufring->size--;
66 
+    }
67 
+    return ret_val;
68 
+}
69 
+
70 
+/*
71 
  * Loads the XKB keymap from the X11 server and feeds it to xkbcommon.
72 
  * Necessary so that we can properly let xkbcommon track the keyboard state and
73 
  * translate keypresses to utf-8.
74 
@@ -187,10 +232,14 @@ static void clear_pam_wrong(EV_P_ ev_timer *w, int revents) {
75 
     clear_pam_wrong_timeout = NULL;
76 
 }
77
78 
-static void clear_input(void) {
79 
+static void reset_input(void) {
80 
     input_position = 0;
81 
     clear_password_memory();
82 
     password[input_position] = '\0';
83 
+}
84 
+
85 
+static void clear_input(void) {
86 
+    reset_input();
87
88 
     /* Hide the unlock indicator after a bit if the password buffer is
89 
      * empty. */
90 
@@ -205,7 +254,6 @@ static void auth_failed(void) {
91 
         fprintf(stderr, "Authentication failure\n");
92
93 
     pam_state = STATE_PAM_WRONG;
94 
-    clear_input();
95 
     redraw_screen();
96
97 
     /* Clear this state after 2 seconds (unless the user enters another
98 
@@ -227,6 +275,9 @@ static void auth_failed(void) {
99 
     }
100 
 }
101
102 
+static void handle_key_press(xcb_key_press_event_t *event);
103 
+static void handle_key_release(xcb_key_release_event_t *event);
104 
+
105 
 static void child_cb(EV_P_ ev_child *child_watcher, int revents) {
106 
     if (child_watcher->rstatus != 0) {
107 
         DEBUG("Authentication successfull\n");
108 
@@ -235,6 +286,17 @@ static void child_cb(EV_P_ ev_child *child_watcher, int revents) {
109 
         exit(0);
110 
     } else {
111 
         auth_failed();
112 
+        xcb_generic_event_t *event;
113 
+        while (pam_state != STATE_PAM_VERIFY
114 
+                && (event = ringbuffer_remove(&buffered_events))) {
115 
+            /* Strip off the highest bit (set if the event is generated) */
116 
+            int type = (event->response_type & 0x7F);
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+            if (type == XCB_KEY_PRESS)
118 
+                handle_key_press((xcb_key_press_event_t*)event);
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+            else if (type == XCB_KEY_RELEASE)
120 
+                handle_key_release((xcb_key_release_event_t*)event);
121 
+            free(event);
122 
+        }
123 
     }
124 
     ev_child_stop(main_loop, child_watcher);
125 
     free(child_watcher);
126 
@@ -259,7 +321,8 @@ static void input_done(void) {
127 
     if (cpid == 0) {
128 
         exit(pam_authenticate(pam_handle, 0) == PAM_SUCCESS);
129 
     } else if (cpid > 0) {
130 
-        struct ev_child *child_watcher = calloc(sizeof(struct ev_io), 1);
131 
+        reset_input();
132 
+        struct ev_child *child_watcher = calloc(sizeof(struct ev_child), 1);
133 
         ev_child_init(child_watcher, child_cb, cpid, 0);
134 
         ev_child_set(child_watcher, cpid, 0);
135 
         ev_child_start(EV_DEFAULT_ child_watcher);
136 
@@ -281,6 +344,11 @@ static void input_done(void) {
137 
  */
138 
 static void handle_key_release(xcb_key_release_event_t *event) {
139 
     xkb_state_update_key(xkb_state, event->detail, XKB_KEY_UP);
140 
+
141 
+    /* If this was the backspace or escape key we are back at an
142 
+     * empty input, so turn off the screen if DPMS is enabled */
143 
+    if (dpms && input_position == 0)
144 
+        dpms_turn_off_screen(conn);
145 
 }
146
147 
 static void redraw_timeout(EV_P_ ev_timer *w, int revents) {
148 
@@ -518,6 +586,14 @@ static void xcb_check_cb(EV_P_ ev_check *w, int revents) {
149
150 
         /* Strip off the highest bit (set if the event is generated) */
151 
         int type = (event->response_type & 0x7F);
152 
+        if (pam_state == STATE_PAM_VERIFY &&
153 
+                (type == XCB_KEY_PRESS || type == XCB_KEY_RELEASE)) {
154 
+            /* Don’t process KeyPress/KeyRelease events when a verification is
155 
+             * in progress. Try to buffer them or drop them if the buffer is full. */
156 
+            if (ringbuffer_add(&buffered_events, event))
157 
+                free(event);
158 
+            continue;
159 
+        }
160 
         switch (type) {
161 
             case XCB_KEY_PRESS:
162 
                 handle_key_press((xcb_key_press_event_t*)event);
163 
@@ -525,12 +601,6 @@ static void xcb_check_cb(EV_P_ ev_check *w, int revents) {
164
165 
             case XCB_KEY_RELEASE:
166 
                 handle_key_release((xcb_key_release_event_t*)event);
167 
-
168 
-                /* If this was the backspace or escape key we are back at an
169 
-                 * empty input, so turn off the screen if DPMS is enabled */
170 
-                if (dpms && input_position == 0)
171 
-                    dpms_turn_off_screen(conn);
172 
-
173 
                 break;
174
175 
             case XCB_VISIBILITY_NOTIFY: