alloca: remove in favour of malloc and friends

alloca() has never been part of the ANSI-C standard, and its use in fvwm
has always been limited.

Rather than keep this around, switch to use malloc() and similar.

fvwm/events.c

@@ -106,11 +106,6 @@
 
 /* ---------------------------- local definitions -------------------------- */
 
-#ifndef C_ALLOCA
-#undef alloca
-#define alloca(x) do { } while (0)
-#endif
-
 #ifndef XUrgencyHint
 #define XUrgencyHint            (1L << 8)
 #endif
@@ -4244,13 +4239,6 @@ void dispatch_event(XEvent *e)
 		(*event_group->jump_table[e->type - event_group->base])(&ea);
 		exc_destroy_context(ea.exc);
 	}
-
-	/* If we're using the C version of alloca, see if anything needs to be
-	 * freed up.
-	 */
-	alloca(0);
-
-	return;
 }
 
 /* ewmh configure request */

fvwm/menustyle.c

@@ -329,7 +329,6 @@ static MenuStyle *menustyle_parse_old_style(F_CMD_ARGS)
 	char *buffer, *rest;
 	char *fore, *back, *stipple, *font, *style, *animated;
 	MenuStyle *ms = NULL;
-	size_t len;
 
 	rest = GetNextToken(action,&fore);
 	rest = GetNextToken(rest,&back);
@@ -345,9 +344,7 @@ static MenuStyle *menustyle_parse_old_style(F_CMD_ARGS)
 	}
 	else
 	{
-		len = strlen(action) + 100;
-		buffer = alloca(len);
-		snprintf(buffer, len,
+		xasprintf(&buffer,
 			"* \"%s\", Foreground \"%s\", Background \"%s\", "
 			"Greyed \"%s\", Font \"%s\", \"%s\"",
 			style, fore, back, stipple, font,
@@ -357,35 +354,20 @@ static MenuStyle *menustyle_parse_old_style(F_CMD_ARGS)
 			   "The old MenuStyle syntax has been deprecated.  "
 			   "Use 'MenuStyle %s' instead of 'MenuStyle %s'\n",
 			   buffer, action);
+
 		action = buffer;
 		ms = menustyle_parse_style(F_PASS_ARGS);
-	}
 
-	if (fore)
-	{
-		free(fore);
-	}
-	if (back)
-	{
-		free(back);
-	}
-	if (stipple)
-	{
-		free(stipple);
-	}
-	if (font)
-	{
-		free(font);
-	}
-	if (style)
-	{
-		free(style);
-	}
-	if (animated)
-	{
-		free(animated);
+		free(buffer);
 	}
 
+	free(fore);
+	free(back);
+	free(stipple);
+	free(font);
+	free(style);
+	free(animated);
+
 	return ms;
 }
 

fvwm/module_list.c

@@ -1115,8 +1115,7 @@ void CMD_ModuleSynchronous(F_CMD_ARGS)
 		token = PeekToken(next, &next);
 		if (token)
 		{
-			expect = alloca(strlen(token) + 1);
-			strcpy(expect, token);
+			expect = fxstrdup(token);
 		}
 		action = next;
 		token = PeekToken(action, &next);
@@ -1131,21 +1130,21 @@ void CMD_ModuleSynchronous(F_CMD_ARGS)
 		else
 		{
 			fvwm_debug(__func__, "illegal timeout");
-			return;
+			goto done;
 		}
 	}
 
 	if (!action)
 	{
 		/* no module name */
-		return;
+		goto done;
 	}
 
 	module = do_execute_module(F_PASS_ARGS, False, False);
 	if (module == NULL)
 	{
 		/* executing the module failed, just return */
-		return;
+		goto done;
 	}
 
 	/* Busy cursor stuff */
@@ -1267,8 +1266,8 @@ void CMD_ModuleSynchronous(F_CMD_ARGS)
 	{
 		UngrabEm(GRAB_BUSY);
 	}
-
-	return;
+done:
+	free(expect);
 }
 
 /* mask handling - does this belong here? */

fvwm/session.c

@@ -745,6 +745,7 @@ set_sm_properties(FSmcConn sm_conn, char *filename, char hint)
 	FSmPropValue prop1val, prop2val, prop3val, prop4val, prop7val;
 	struct passwd *pwd;
 	char *user_id;
+	char *discardCommand;
 	char screen_num[32];
 	int numVals, i, priority = 30;
 	Bool is_xsm_detected = False;
@@ -890,9 +891,7 @@ set_sm_properties(FSmcConn sm_conn, char *filename, char hint)
 			   should be LISTofARRAY8 on posix systems, but xsm
 			   demands that it be ARRAY8.
 			*/
-			size_t len = 10 + strlen(filename);
-			char *discardCommand = alloca(len);
-			snprintf (discardCommand, len, "rm -f '%s'", filename);
+			xasprintf(&discardCommand, "rm -f '%s'", filename);
 			prop7.type = FSmARRAY8;
 			prop7.num_vals = 1;
 			prop7.vals = &prop7val;
@@ -937,7 +936,8 @@ set_sm_properties(FSmcConn sm_conn, char *filename, char hint)
 	{
 		FSmcSetProperties (sm_conn, 5, props);
 	}
-	free ((char *) prop5.vals);
+	free((char *) prop5.vals);
+	free(discardCommand);
 }
 
 static void

libs/Bindings.c

@@ -827,8 +827,7 @@ KeySym FvwmStringToKeysym(Display *dpy, char *key)
 	}
 	else
 	{
-		s = alloca(strlen(key) + 1);
-		strcpy(s, key);
+		s = fxstrdup(key);
 		/* always prefer the lower case spelling if it exists */
 		*s = tolower(*s);
 		keysym = XStringToKeysym(s);
@@ -837,6 +836,7 @@ KeySym FvwmStringToKeysym(Display *dpy, char *key)
 			*s = toupper(*s);
 			keysym = XStringToKeysym(s);
 		}
+		free(s);
 	}
 	if (keysym == NoSymbol || XKeysymToKeycode(dpy, keysym) == 0)
 	{

libs/Graphics.c

@@ -119,7 +119,7 @@ void do_relieve_rectangle_with_rotation(
 	}
 	max_w = min((w + 1) / 2, line_width);
 	max_h = min((h + 1) / 2, line_width);
-	seg = (XSegment*)alloca((sizeof(XSegment) * line_width) * 2);
+	seg = fxmalloc(sizeof(XSegment) * line_width * 2);
 	/* from 0 to the lesser of line_width & just over half w */
 
 	/* left */
@@ -147,6 +147,9 @@ void do_relieve_rectangle_with_rotation(
 	}
 	XDrawSegments(dpy, d, shadow_gc, seg, cur);
 
+	if (seg)
+		XFree(seg);
+
 	return;
 }
 
@@ -535,7 +538,7 @@ static XColor *AllocNonlinearGradient(
 	XColor *xcs = fxmalloc(sizeof(XColor) * npixels);
 	int i;
 	int curpixel = 0;
-	int *seg_end_colors;
+	int *seg_end_colors = NULL;
 	int seg_sum = 0;
 	float color_sum = 0.0;
 
@@ -545,7 +548,8 @@ static XColor *AllocNonlinearGradient(
 			   "Gradients must specify at least one segment and"
 			   " two colors\n");
 		free(xcs);
-		return NULL;
+		xcs = NULL;
+		goto done;
 	}
 	for (i = 0; i < npixels; i++)
 	{
@@ -559,7 +563,7 @@ static XColor *AllocNonlinearGradient(
 	}
 
 	/* calculate the index of a segment's las color */
-	seg_end_colors = alloca(nsegs * sizeof(int));
+	seg_end_colors = fxmalloc(nsegs * sizeof(int));
 	if (nsegs == 1)
 	{
 		seg_end_colors[0] = npixels - 1;
@@ -580,7 +584,9 @@ static XColor *AllocNonlinearGradient(
 				   " > npixels - 1 (%d)."
 				   " Gradient drawing aborted\n",
 				   seg_end_colors[nsegs - 1], npixels - 1);
-			return NULL;
+			free(xcs);
+			xcs = NULL;
+			goto done;
 		}
 		/* take care of rounding errors */
 		seg_end_colors[nsegs - 1] = npixels - 1;
@@ -610,7 +616,8 @@ static XColor *AllocNonlinearGradient(
 			if (!c && (n - skip_first_color) != 0)
 			{
 				free(xcs);
-				return NULL;
+				xcs = NULL;
+				goto done;
 			}
 			for (j = skip_first_color; j < n; ++j)
 			{
@@ -632,9 +639,13 @@ static XColor *AllocNonlinearGradient(
 				   " npixels %d, n %d\n",
 				   nsegs, i, curpixel,
 				   seg_end_colors[i],npixels,n);
-			return NULL;
+			free(xcs);
+			xcs = NULL;
+			goto done;
 		}
 	}
+done:
+	free(seg_end_colors);
 	return xcs;
 }
 

libs/Module.c

@@ -144,7 +144,7 @@ void SendText(int *fd, const char *message, unsigned long window)
 
 	/* Get enough memory to store the entire message. */
 	len = strlen(message);
-	p = buf = alloca(sizeof(long) * (3 + 1 + (len / sizeof(long))));
+	p = buf = fxmalloc(sizeof(long) * (3 + 1 + (len / sizeof(long))));
 
 	/* Put the message in the buffer, and... */
 	*((unsigned long *)p) = window;
@@ -166,6 +166,7 @@ void SendText(int *fd, const char *message, unsigned long window)
 		n = write(fd[0], buf, p - buf);
 		(void)n;
 	}
+	free(buf);
 }
 
 /*
@@ -183,13 +184,14 @@ void SendFvwmPipe(int *fd, const char *message, unsigned long window)
 
 	while ((temp = strchr(hold, ',')) != NULL)
 	{
-		char *temp_msg = (char*)alloca(temp - hold + 1);
+		char *temp_msg = fxmalloc(temp - hold + 1);
 
 		strncpy(temp_msg, hold, (temp - hold));
 		temp_msg[(temp - hold)] = '\0';
 		hold = temp + 1;
 
 		SendText(fd, temp_msg, window);
+		free(temp_msg);
 	}
 
 	/*
@@ -241,11 +243,12 @@ static int first_pass = 1;
 
 void InitGetConfigLine(int *fd, char *match)
 {
-	size_t len = strlen(match) + 32;
-	char *buffer = alloca(len);
+	char *buffer;
+
 	first_pass = 0;              /* make sure get wont do this */
-	snprintf(buffer, len, "Send_ConfigInfo %s", match);
+	xasprintf(&buffer, "Send_ConfigInfo %s", match);
 	SendText(fd, buffer, 0);
+	free(buffer);
 }
 
 

libs/fvwmsignal.c

@@ -164,13 +164,6 @@ fvwmSelect(fd_set_size_t nfds,
 {
 	volatile int iRet = -1;  /* This variable MUST NOT be in a register */
 
-#ifdef C_ALLOCA
-	/* If we're using the C version of alloca, see if anything needs to be
-	 * freed up.
-	 */
-	alloca(0);
-#endif
-
 	/*
 	 * Yes, we trash errno here, but you're only supposed to check
 	 * errno immediately after a function fails anyway. If we fail,

modules/FvwmPager/x_pager.c

@@ -1047,10 +1047,7 @@ void UpdateWindowShape(void)
     shape_count =
       ndesks + ((m->virtual_scr.CurrentDesk < desk1 || m->virtual_scr.CurrentDesk >desk2) ? 0 : 1);
 
-    shape = (XRectangle *)alloca (shape_count * sizeof (XRectangle));
-
-    if (shape == NULL)
-      return;
+    shape = fxmalloc(shape_count * sizeof (XRectangle));
 
     cnt = 0;
     y_pos = (LabelsBelow ? 0 : label_h);
@@ -1084,6 +1081,7 @@ void UpdateWindowShape(void)
 
     FShapeCombineRectangles(
       dpy, Scr.Pager_w, FShapeBounding, 0, 0, shape, shape_count, FShapeSet, 0);
+    free(shape);
   }
 }