Upgraded the dwmblocks patch for statuscmd which changes the signalling

mechanism from SIGUSR1 to SIGRTMIN which is likely to cause issues for
those that already have a working setup. A compatibility option has been
added which changes this back to SIGUSR1. Note that configuration was
also changed.

This was ref. reported issue #114.

README.md

@@ -15,6 +15,8 @@ Refer to [https://dwm.suckless.org/](https://dwm.suckless.org/) for details on t
 
 ### Changelog:
 
+2021-04-14 - Upgraded the dwmblocks patch for statuscmd which changes the signalling mechanism from SIGUSR1 to SIGRTMIN which is likely to cause issues for those that already have a working setup. A compatibility option has been added which changes this back to SIGUSR1. Note that configuration was also changed.
+
 2021-04-07 - Added xkb patch
 
 2021-04-06 - Added the distributetags patch

config.def.h

@@ -774,11 +774,16 @@ static const char *dmenucmd[] = {
 };
 static const char *termcmd[]  = { "st", NULL };
 
-#if BAR_STATUSCMD_PATCH && !BAR_DWMBLOCKS_PATCH
+#if BAR_STATUSCMD_PATCH
+#if BAR_DWMBLOCKS_PATCH
+/* This defines the name of the executable that handles the bar (used for signalling purposes) */
+#define STATUSBAR "dwmblocks"
+#else
 /* commands spawned when clicking statusbar, the mouse button pressed is exported as BUTTON */
-static const char *statuscmds[] = { "notify-send Mouse$BUTTON" };
+static const char *statuscmds[] = { "notify-send Mouse$BUTTON", "notify-send Cat$BUTTON", "notify-send Dog$BUTTON" };
 static char *statuscmd[] = { "/bin/sh", "-c", NULL, NULL };
-#endif // BAR_STATUSCMD_PATCH | DWMBLOCKS_PATCH
+#endif // BAR_DWMBLOCKS_PATCH
+#endif // BAR_STATUSCMD_PATCH
 
 #if ON_EMPTY_KEYS_PATCH
 static const char* firefoxcmd[] = {"firefox", NULL};
@@ -1209,9 +1214,9 @@ static Button buttons[] = {
 	#endif // BAR_WINTITLEACTIONS_PATCH
 	{ ClkWinTitle,          0,                   Button2,        zoom,           {0} },
 	#if BAR_STATUSCMD_PATCH && BAR_DWMBLOCKS_PATCH
-	{ ClkStatusText,        0,                   Button1,        sigdwmblocks,   {.i = 1 } },
-	{ ClkStatusText,        0,                   Button2,        sigdwmblocks,   {.i = 2 } },
-	{ ClkStatusText,        0,                   Button3,        sigdwmblocks,   {.i = 3 } },
+	{ ClkStatusText,        0,                   Button1,        sigstatusbar,   {.i = 1 } },
+	{ ClkStatusText,        0,                   Button2,        sigstatusbar,   {.i = 2 } },
+	{ ClkStatusText,        0,                   Button3,        sigstatusbar,   {.i = 3 } },
 	#elif BAR_STATUSCMD_PATCH
 	{ ClkStatusText,        0,                   Button1,        spawn,          {.v = statuscmd } },
 	{ ClkStatusText,        0,                   Button2,        spawn,          {.v = statuscmd } },

patch/bar_dwmblocks.c

@@ -1,31 +1,50 @@
-static int dwmblockssig;
-pid_t dwmblockspid = 0;
+static int statussig;
+pid_t statuspid = -1;
 
-int
-getdwmblockspid()
+pid_t
+getstatusbarpid()
 {
-	char buf[16];
-	FILE *fp = popen("pidof -s dwmblocks", "r");
-	if (fgets(buf, sizeof(buf), fp));
-	pid_t pid = strtoul(buf, NULL, 10);
+	char buf[32], *str = buf, *c;
+	FILE *fp;
+
+	if (statuspid > 0) {
+		snprintf(buf, sizeof(buf), "/proc/%u/cmdline", statuspid);
+		if ((fp = fopen(buf, "r"))) {
+			fgets(buf, sizeof(buf), fp);
+			while ((c = strchr(str, '/')))
+				str = c + 1;
+			fclose(fp);
+			if (!strcmp(str, STATUSBAR))
+				return statuspid;
+		}
+	}
+	if (!(fp = popen("pidof -s "STATUSBAR, "r")))
+		return -1;
+	fgets(buf, sizeof(buf), fp);
 	pclose(fp);
-	dwmblockspid = pid;
-	return pid != 0 ? 0 : -1;
+	return strtol(buf, NULL, 10);
 }
 
 void
-sigdwmblocks(const Arg *arg)
+sigstatusbar(const Arg *arg)
 {
 	union sigval sv;
-	sv.sival_int = (dwmblockssig << 8) | arg->i;
-	if (!dwmblockspid)
-		if (getdwmblockspid() == -1)
-			return;
 
-	if (sigqueue(dwmblockspid, SIGUSR1, sv) == -1) {
+	if (!statussig)
+		return;
+	if ((statuspid = getstatusbarpid()) <= 0)
+		return;
+
+	#if BAR_DWMBLOCKS_SIGUSR1_PATCH
+	sv.sival_int = (statussig << 8) | arg->i;
+	if (sigqueue(statuspid, SIGUSR1, sv) == -1) {
 		if (errno == ESRCH) {
-			if (!getdwmblockspid())
-				sigqueue(dwmblockspid, SIGUSR1, sv);
+			if (!getstatusbarpid())
+				sigqueue(statuspid, SIGUSR1, sv);
 		}
 	}
+	#else
+	sv.sival_int = arg->i;
+	sigqueue(statuspid, SIGRTMIN+statussig, sv);
+	#endif // BAR_DWMBLOCKS_SIGUSR1_PATCH
 }

patch/bar_dwmblocks.h

@@ -1,2 +1,2 @@
-static int getdwmblockspid();
-static void sigdwmblocks(const Arg *arg);
+static int getstatusbarpid();
+static void sigstatusbar(const Arg *arg);

patch/bar_statuscmd.c

@@ -25,7 +25,7 @@ click_statuscmd_text(Arg *arg, int rel_x, char *text)
 	int x = 0;
 	char ch;
 	#if BAR_DWMBLOCKS_PATCH
-	dwmblockssig = -1;
+	statussig = -1;
 	#else
 	statuscmdn = 0;
 	#endif // BAR_DWMBLOCKS_PATCH
@@ -42,9 +42,9 @@ click_statuscmd_text(Arg *arg, int rel_x, char *text)
 			text += i+1;
 			i = -1;
 			#if BAR_DWMBLOCKS_PATCH
-			if (x >= rel_x && dwmblockssig != -1)
+			if (x >= rel_x && statussig != -1)
 				break;
-			dwmblockssig = ch;
+			statussig = ch;
 			#else
 			if (x >= rel_x)
 				break;
@@ -54,8 +54,8 @@ click_statuscmd_text(Arg *arg, int rel_x, char *text)
 		}
 	}
 	#if BAR_DWMBLOCKS_PATCH
-	if (dwmblockssig == -1)
-		dwmblockssig = 0;
+	if (statussig == -1)
+		statussig = 0;
 	#endif // BAR_DWMBLOCKS_PATCH
 	return ClkStatusText;
 }

patches.def.h

@@ -21,13 +21,38 @@
  */
 #define BAR_AWESOMEBAR_PATCH 0
 
-/* This patch depends on statuscmd patch and adds integration with a (patched) dwmblocks
- * instance to give a clickable status bar.
- * Patch: https://gist.github.com/danbyl/54f7c1d57fc6507242a95b71c3d8fdea
+/* This patch depends on statuscmd patch and adds integration with a (patched)
+ * dwmblocks instance to give a clickable status bar. One must not necessarily
+ * have to use dwmblocks for this feature, any status updater that has support
+ * for real-time signals (SIGRTMIN) can be used.
+ *
  * dwmblocks: https://github.com/torrinfail/dwmblocks
+ * https://dwm.suckless.org/patches/statuscmd/
  */
 #define BAR_DWMBLOCKS_PATCH 0
 
+/* Originally the dwmblocks + statuscmd patch used a user defined signal (SIGUSR1)
+ * for communicating with dwmblocks to indicate update signal and what button was
+ * pressed. The signalling was later changed to SIGRTMIN instead.
+ *
+ * Ultimately this makes dwmblocks instances that were patched with the old patch
+ * are incompatible with the new dwm patch and vice versa.
+ *
+ * This is a compatibility patch that makes dwm use SIGUSR1 instead of SIGRTMIN so
+ * if button clicks are not working then you may want to try enabling this.
+ *
+ * If dwmblocks happen to die like this when clicking on a status
+ *
+ *    [1]    54355 user-defined signal 1  dwmblocks
+ *
+ * then it suggests that dwmblocks does not support user defined signals and this
+ * patch should be left disabled.
+ *
+ * Patch: https://gist.github.com/danbyl/54f7c1d57fc6507242a95b71c3d8fdea
+ * https://dwm.suckless.org/patches/statuscmd/
+ */
+#define BAR_DWMBLOCKS_SIGUSR1_PATCH 0
+
 /* This patch shows the titles of all visible windows in the status bar
  * (as opposed to showing only the selected one).
  * Awesomebar takes precedence over fancybar. Fancybar takes precedence over