Centralize catgets() calls through MsgCat

CDE has relied upon catgets() implementations following a relaxed
interpretation of the XPG internationalization standard that ignored
-1, the standard error value returned by catopen, as the catalog
argument. However, this same behavior causes segmentation faults with
the musl C library.

This patch:

- Centralizes (with the exception of ToolTalk) all calls to catopen(),
  catgets(), and catclose() through MsgCat within the DtSvc library.
- Prevents calls to catgets() and catclose() that rely upon
  undefined behavior.
- Eliminates a number of bespoke catgets() wrappers, including multiple
  redundant caching implementations designed to work around a design
  peculiarity in HP/UX.
- Eases building CDE without XPG internationalization support by providing
  the appropriate macros.

cde/lib/DtSvc/DtUtil2/DtGetMessage.c

@@ -42,7 +42,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <nl_types.h>
+#include <Dt/MsgCatP.h>
 #include "DtSvcLock.h"
 
 /*****************************************************************************
@@ -79,7 +79,7 @@ Dt11GetMessage(
 	_DtSvcProcessLock();
         if ( NULL == nlmsg_filename || 0 != strcmp(nlmsg_filename, filename) )
         {
-		nlmsg_fd = catopen(filename, NL_CAT_LOCALE);
+		nlmsg_fd = CATOPEN(filename, NL_CAT_LOCALE);
 		if (nlmsg_filename)
 		{
 		    free(nlmsg_filename);
@@ -87,7 +87,7 @@ Dt11GetMessage(
 		}
 		nlmsg_filename = strdup(filename);
         }
-        msg=catgets(nlmsg_fd,set,n,s);
+        msg=CATGETS(nlmsg_fd,set,n,s);
 	_DtSvcProcessUnlock();
         return (msg);
 }

cde/lib/DtSvc/DtUtil2/GetMessage.c

@@ -45,7 +45,7 @@
  ************************************<+>*************************************/
 
 #include <stdio.h>
-#include <nl_types.h>
+#include <Dt/MsgCatP.h>
 #include "DtSvcLock.h"
 
 #if !defined(NL_CAT_LOCALE)
@@ -80,8 +80,6 @@ _DtGetMessage(
 {
         char *msg;
 	char *lang;
-	nl_catd catopen();
-	char *catgets();
 	static int first = 1;
 	static nl_catd nlmsg_fd;
 
@@ -89,9 +87,9 @@ _DtGetMessage(
 	if ( first ) 
         {
 		first = 0;
-		nlmsg_fd = catopen(filename, NL_CAT_LOCALE);
+		nlmsg_fd = CATOPEN(filename, NL_CAT_LOCALE);
 	}
-	msg=catgets(nlmsg_fd,set,n,s);
+	msg=CATGETS(nlmsg_fd,set,n,s);
 	_DtSvcProcessUnlock();
 	return (msg);
 }

cde/lib/DtSvc/DtUtil2/MsgCat.c

@@ -37,11 +37,18 @@
 
 #include <stdio.h>
 #include <string.h>
-#include <nl_types.h>
-#include <X11/Intrinsic.h>
-#include <Dt/MsgCatP.h>
-#include <DtSvcLock.h>
 
+#if defined(NO_XLIB)
+#define _DtSvcProcessLock()
+#define _DtSvcProcessUnlock()
+#else
+#include <X11/Intrinsic.h>
+#include <DtSvcLock.h>
+#endif /* NO_XLIB */
+
+#include <Dt/MsgCatP.h>
+
+#if defined(hpV4) && !defined(NO_XLIB)
 typedef struct _dt_msg_cache
 {
     char ***cached_msgs;
@@ -56,8 +63,8 @@ static _DtMsgCache	*catalog_message_caches = NULL;
 
 static _DtMsgCache *get_msg_cache(nl_catd catd)
 {
-    #define INITIAL_NMSGS_PER_SET	300
-    #define INITIAL_NSETS		50
+    const int initial_nmsgs_per_set = 300;
+    const int initial_nsets         = 50;
 
     _DtMsgCache *c;
 
@@ -66,28 +73,23 @@ static _DtMsgCache *get_msg_cache(nl_catd catd)
 
     c = (_DtMsgCache*) XtMalloc(sizeof(_DtMsgCache));
     c->cached_msgs = NULL;
-    c->nmsgs_per_set = INITIAL_NMSGS_PER_SET;
-    c->nsets = INITIAL_NSETS;
+    c->nmsgs_per_set = initial_nmsgs_per_set;
+    c->nsets = initial_nsets;
     c->catd = catd;
     c->next = catalog_message_caches;
     catalog_message_caches = c;
     return c;
 }
 
-
 /*
  * Wrapper around catgets -- this makes sure the message string is saved
  * in a safe location; so repeated calls to catgets() do not overwrite
  * the catgets() internal buffer.  This has been a problem on HP systems.
  */
-char *_DtCatgetsCached(nl_catd catd, int set, int num, char *dflt)
+char *_DtCatgetsCached(nl_catd catd, int set, int num, const char *dflt)
 {
-    char	*message;
-
-#if !defined(hpV4)
-    message = catgets(catd, set, num, dflt);
-#else
-    _DtMsgCache *c;
+    char	*message = NULL;
+    _DtMsgCache	*c;
     char	**setptr;
     int		i, multiplier;
     int		size;
@@ -96,8 +98,6 @@ char *_DtCatgetsCached(nl_catd catd, int set, int num, char *dflt)
     int		setIdx = set - 1;
     int		numIdx = num - 1;
 
-    _DtSvcProcessLock();
-
     c = get_msg_cache(catd);
     if (NULL == c) 
     {
@@ -150,8 +150,32 @@ char *_DtCatgetsCached(nl_catd catd, int set, int num, char *dflt)
   
     message = setptr[numIdx];
 
-    _DtSvcProcessUnlock();
-#endif /* hpV4 */
-
     return message;
 }
+#endif /* hpV4 */
+
+int _DtCatclose(nl_catd catd)
+{
+    return (catd == (nl_catd) -1) ? 0 : catclose(catd);
+}
+
+char *_DtCatgets(nl_catd catd, int set, int num, const char *dflt)
+{
+    char *msg = NULL;
+
+    if (catd == (nl_catd) -1 || set < 0 || num < 0) {
+      /* Some catgets() implementations will fault if catd is invalid. */
+      msg = (char *) dflt;
+    } else {
+      /* Per POSIX, we cannot assume catgets() is thread-safe. */
+      _DtSvcProcessLock();
+#if defined(hpV4) && !defined(NO_XLIB)
+      msg = _DtCatgetsCached(catd, set, num, dflt);
+#else
+      msg = catgets(catd, set, num, dflt);
+#endif /* hpV4 */
+      _DtSvcProcessUnlock();
+    }
+
+   return msg;
+}