Re: [AD] xmessage broken pipe

[Chris <chris.kcat@xxxxxxxxxx>]

Peter Wang wrote:
> I thought of a slight problem with this approach.  If the message is 
> "-print", "-center" or "-nearmouse" (and perhaps other options in 
> future) then xmessage will think it is an option argument.  A workaround 
> is to put an extra space at the end of the message string (say, after 
> the uconvert) before passing it to xmessage.

This patch fixes allegro_message itself to make this impossible to 
happen. The Allegro docs neglect to mention whether or not you need a 
trailing \n character, even though when it prints to the console you'll 
get improper lining without it (printing a string without the trailing 
\n and then quitting, for example, will cause the shell prompt to append 
to the very end of the printed message). And because of the prevalence 
of Windows and now X using xmessage, it might not be apparent that you'd 
need it.

The patch also fixes a problem with the two mallocs not being checked 
for success.
Index: src/allegro.c
===================================================================
RCS file: /cvsroot/alleg/allegro/src/allegro.c,v
retrieving revision 1.46
diff -b -u -r1.46 allegro.c
--- src/allegro.c	4 Dec 2004 12:59:50 -0000	1.46
+++ src/allegro.c	11 Dec 2004 01:31:43 -0000
@@ -430,16 +430,28 @@
    char *buf = malloc(ALLEGRO_MESSAGE_SIZE);
    char *tmp = malloc(ALLEGRO_MESSAGE_SIZE);
    va_list ap;
+   int len;
+
    ASSERT(msg);
+
+   if ((buf == NULL) || (tmp == NULL))
+      goto quit;
+
    va_start(ap, msg);
-   uvszprintf(buf, ALLEGRO_MESSAGE_SIZE, msg, ap);
+   len = uvszprintf(buf, ALLEGRO_MESSAGE_SIZE, msg, ap);
    va_end(ap);
 
+   if ((ugetc(buf+len-ucwidth('\n')) != '\n') && (len < ALLEGRO_MESSAGE_SIZE-ucwidth('\n')-ucwidth('\0'))) {
+      usetc(buf+len, '\n');
+      usetc(buf+len+ucwidth('\n'), '\0');
+   }
+
    if ((system_driver) && (system_driver->message))
       system_driver->message(buf);
    else
       fputs(uconvert(buf, U_CURRENT, tmp, U_ASCII_CP, ALLEGRO_MESSAGE_SIZE), stdout);
 
+quit:
    free(buf);
    free(tmp);
 }