use malloc-based sbrk() replacement

Makefile

@@ -214,18 +214,9 @@ OSTYPE	= -DVMUNIX
 TERMLIB	= termlib
 
 #
-# Since ex uses sbrk() internally, a conflict with the libc's version of
-# malloc() must be avoided. There are two ways to work around this problem.
-# The first is to allocate a static pool for all malloc purposes. This will
-# work on any kind of system.
-#
-#MALLOC=malloc.o
-#
-# If mmap() can be used to allocate anonymous memory, this is the preferred
-# choice as it allows to grow memory dynamically as it is needed. This will
-# usually work unless you are compiling for a vector machine or another
-# unusual enviroment.
-MALLOC=mapmalloc.o
+# Malloc-based sbrk() substitution.
+#
+MALLOC=sbreak.o
 
 ###############################################################################
 #                                                                             #
@@ -350,7 +341,7 @@ ex.pkg: all
 	rm -rf $(PKGROOT) $(PKGPROTO) $(PKGTEMP)/$@
 
 ex.o: config.h ex_argv.h ex.h ex_proto.h ex_temp.h ex_tty.h ex_tune.h
-ex.o: ex_vars.h libterm/libterm.h
+ex.o: ex_vars.h sbreak.h libterm/libterm.h
 ex_addr.o: config.h ex.h ex_proto.h ex_re.h ex_tune.h ex_vars.h
 ex_cmds.o: config.h ex_argv.h ex.h ex_proto.h ex_temp.h ex_tty.h ex_tune.h
 ex_cmds.o: ex_vars.h ex_vis.h libterm/libterm.h
@@ -372,7 +363,7 @@ ex_re.o: config.h ex.h ex_proto.h ex_re.h ex_tune.h ex_vars.h
 ex_set.o: config.h ex.h ex_proto.h ex_temp.h ex_tty.h ex_tune.h ex_vars.h
 ex_set.o: libterm/libterm.h
 ex_subr.o: config.h ex.h ex_proto.h ex_re.h ex_tty.h ex_tune.h ex_vars.h
-ex_subr.o: ex_vis.h libterm/libterm.h
+ex_subr.o: ex_vis.h sbreak.h libterm/libterm.h
 ex_tagio.o: config.h ex.h ex_proto.h ex_tune.h ex_vars.h
 ex_temp.o: config.h ex.h ex_proto.h ex_temp.h ex_tty.h ex_tune.h ex_vars.h
 ex_temp.o: ex_vis.h libterm/libterm.h

README

@@ -63,19 +63,8 @@ Prerequisites for ports to other systems are:
 
 - The system must provide an ANSI C-89 compiler and POSIX.1-1990 functions.
 
-- The system must provide an sbrk() call to increase the memory heap size.
-  If only a fake sbrk() call is provided that works by pre-allocating
-  several MB, vi will probably work too.
-
-- The system library must allow replacement of malloc() and printf() by the
-  versions provided by vi. For malloc(), it also must make its own internal
-  memory requests using the vi malloc(). Otherwise, vi will likely die with
-  a segmentation fault because the storage allocated by sbrk() interferes
-  with usual Unix library implementations of malloc().
-
-The last two requirements could probably be eliminated with some effort, but
-it would not result in any real improvements for usual the Unix platforms vi
-is targeted at, so it has not be done yet.
+- The system library must allow replacement of printf() by the version
+  provided by vi.
 
 
 Terminal capabilities

ex.c

@@ -87,6 +87,7 @@ static char sccsid[] = "@(#)ex.c	1.37 (gritter) 8/4/05";
 #include "ex_argv.h"
 #include "ex_temp.h"
 #include "ex_tty.h"
+#include "sbreak.h"
 
 #ifdef TRACE
 char	tttrace[]	= { '/','d','e','v','/','t','t','y','x','x',0 };
@@ -529,7 +530,7 @@ main(register int ac, register char *av[])
 	 * this as ed does, saving a little core, but it will probably
 	 * not often make much difference.
 	 */
-	fendcore = (line *) sbrk(0);
+	fendcore = (line *) sbreak(0);
 	endcore = fendcore - 2;
 
 #ifdef SIGTSTP

ex_subr.c

@@ -83,6 +83,7 @@ static char sccsid[] = "@(#)ex_subr.c	1.41 (gritter) 12/25/06";
 #include "ex_re.h"
 #include "ex_tty.h"
 #include "ex_vis.h"
+#include "sbreak.h"
 
 short	lastsc;
 
@@ -490,14 +491,14 @@ morelines(void)
 			pg = 4096;
 		pg /= sizeof (line);
 	}
-	if ((char *)sbrk(pg * sizeof (line)) == (char *)-1)
+	if ((char *)sbreak(pg * sizeof (line)) == (char *)-1)
 		return (-1);
-	endcore += pg;
+	endcore = sbreak(0) - sizeof(line);
 	return (0);
 #else	/* !_SC_PAGESIZE */
-	if (sbrk(1024 * sizeof (line)) == (char *)-1)
+	if (sbreak(1024 * sizeof (line)) == (char *)-1)
 		return (-1);
-	endcore += 1024;
+	endcore = sbreak(0) - sizeof(line);
 	return (0);
 #endif	/* !_SC_PAGESIZE */
 }

sbreak.c

@@ -0,0 +1,106 @@
+/*
+ * AT&T Unix 7th Edition memory allocation routines.
+ *
+ * Modified for ex by Gunnar Ritter, Freiburg i. Br., Germany,
+ * July 2000.
+ *
+ * Copyright(C) Caldera International Inc. 2001-2002. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *   Redistributions of source code and documentation must retain the
+ *    above copyright notice, this list of conditions and the following
+ *    disclaimer.
+ *   Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *   All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *      This product includes software developed or owned by Caldera
+ *      International, Inc.
+ *   Neither the name of Caldera International, Inc. nor the names of
+ *    other contributors may be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA
+ * INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE
+ * LIABLE FOR ANY DIRECT, INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifdef	VMUNIX
+
+#include <sys/types.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "config.h"
+#include "ex.h"
+
+#ifdef	LANGMSG
+#include <nl_types.h>
+extern	nl_catd	catd;
+#else
+#define	catgets(a, b, c, d)	(d)
+#endif
+
+#define	POOL	32768
+
+char *pool = NULL;
+intptr_t ps = 0;
+
+char *
+poolsbrk(intptr_t unused)
+{
+	intptr_t os, ns;
+
+	if (pool == NULL) {
+		if ((pool = malloc(POOL)) == NULL)
+			error(catgets(catd, 1, 241,
+				"No memory pool"));
+		ps = POOL;
+	}
+	return NULL;
+}
+
+void
+shiftptr(size_t incr)
+{
+	fendcore = (line *) ((char *)fendcore + incr);
+	endcore = (line *) ((char *)endcore + incr);
+	addr1 = (line *) ((char *)addr1 + incr);
+	addr2 = (line *) ((char *)addr2 + incr);
+	dol = (line *) ((char *)dol + incr);
+	dot = (line *) ((char *)dot + incr);
+	one = (line *) ((char *)one + incr);
+	truedol = (line *) ((char *)truedol + incr);
+	unddol = (line *) ((char *)unddol + incr);
+	zero = (line *) ((char *)zero + incr);
+}
+
+void *
+sbreak(size_t incr)
+{
+	char *oldpool = pool;
+
+	if (incr == 0)
+		return pool + ps;
+	if ((pool = realloc(pool, ps + incr)) == NULL)
+		return (void *)-1;
+	ps += incr;
+	if (pool != oldpool)
+		shiftptr(pool - oldpool);
+	return pool;
+}
+
+#endif /* VMUNIX */

sbreak.h

@@ -0,0 +1,2 @@
+char *poolsbrk(intptr_t inc);
+void *sbreak(size_t incr);