add recallocarray replacement and dependency

recallocarray() needs getpagesize() so add a tiny replacement for that.

configure.ac

@@ -1678,6 +1678,7 @@ AC_CHECK_FUNCS([ \
 	getgrouplist \
 	getnameinfo \
 	getopt \
+	getpagesize \
 	getpeereid \
 	getpeerucred \
 	getpgid \
@@ -1708,6 +1709,7 @@ AC_CHECK_FUNCS([ \
 	readpassphrase \
 	reallocarray \
 	recvmsg \
+	recallocarray \
 	rresvport_af \
 	sendmsg \
 	setdtablesize \

openbsd-compat/Makefile.in

@@ -16,9 +16,9 @@ RANLIB=@RANLIB@
 INSTALL=@INSTALL@
 LDFLAGS=-L. @LDFLAGS@
 
-OPENBSD=base64.o basename.o bcrypt_pbkdf.o bindresvport.o blowfish.o daemon.o dirname.o fmt_scaled.o getcwd.o getgrouplist.o getopt_long.o getrrsetbyname.o glob.o inet_aton.o inet_ntoa.o inet_ntop.o mktemp.o pwcache.o readpassphrase.o reallocarray.o realpath.o rresvport.o setenv.o setproctitle.o sha1.o sha2.o rmd160.o md5.o sigact.o strcasestr.o strlcat.o strlcpy.o strmode.o strnlen.o strptime.o strsep.o strtonum.o strtoll.o strtoul.o strtoull.o timingsafe_bcmp.o vis.o blowfish.o bcrypt_pbkdf.o explicit_bzero.o
+OPENBSD=base64.o basename.o bcrypt_pbkdf.o bindresvport.o blowfish.o daemon.o dirname.o fmt_scaled.o getcwd.o getgrouplist.o getopt_long.o getrrsetbyname.o glob.o inet_aton.o inet_ntoa.o inet_ntop.o mktemp.o pwcache.o readpassphrase.o reallocarray.o realpath.o recallocarray.o rresvport.o setenv.o setproctitle.o sha1.o sha2.o rmd160.o md5.o sigact.o strcasestr.o strlcat.o strlcpy.o strmode.o strnlen.o strptime.o strsep.o strtonum.o strtoll.o strtoul.o strtoull.o timingsafe_bcmp.o vis.o blowfish.o bcrypt_pbkdf.o explicit_bzero.o
 
-COMPAT=arc4random.o bsd-asprintf.o bsd-closefrom.o bsd-cray.o bsd-cygwin_util.o bsd-getpeereid.o getrrsetbyname-ldns.o bsd-err.o bsd-misc.o bsd-nextstep.o bsd-openpty.o bsd-poll.o bsd-setres_id.o bsd-snprintf.o bsd-statvfs.o bsd-waitpid.o fake-rfc2553.o openssl-compat.o xcrypt.o kludge-fd_set.o
+COMPAT=arc4random.o bsd-asprintf.o bsd-closefrom.o bsd-cray.o bsd-cygwin_util.o bsd-getpeereid.o getrrsetbyname-ldns.o bsd-err.o bsd-getpagesize.o bsd-misc.o bsd-nextstep.o bsd-openpty.o bsd-poll.o bsd-setres_id.o bsd-snprintf.o bsd-statvfs.o bsd-waitpid.o fake-rfc2553.o openssl-compat.o xcrypt.o kludge-fd_set.o
 
 PORTS=port-aix.o port-irix.o port-linux.o port-solaris.o port-tun.o port-uw.o
 

openbsd-compat/bsd-getpagesize.c

@@ -0,0 +1,23 @@
+/* Placed in the public domain */
+
+#ifndef HAVE_GETPAGESIZE
+
+#include <unistd.h>
+#include <limits.h>
+
+int
+getpagesize(void)
+{
+#if defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
+	long r = sysconf(_SC_PAGESIZE);
+	if (r > 0 && r < INT_MAX)
+		return (int)r;
+#endif
+	/*
+	 * This is at the lower end of common values and appropriate for
+	 * our current use of getpagesize() in recallocarray().
+	 */
+	return 4096;
+}
+
+#endif /* HAVE_GETPAGESIZE */

openbsd-compat/openbsd-compat.h

@@ -60,6 +60,10 @@ int bindresvport_sa(int sd, struct sockaddr *sa);
 void closefrom(int);
 #endif
 
+#ifndef HAVE_GETPAGESIZE
+int getpagesize(void);
+#endif
+
 #ifndef HAVE_GETCWD
 char *getcwd(char *pt, size_t size);
 #endif
@@ -68,6 +72,10 @@ char *getcwd(char *pt, size_t size);
 void *reallocarray(void *, size_t, size_t);
 #endif
 
+#ifndef HAVE_RECALLOCARRAY
+void *recallocarray(void *, size_t, size_t, size_t);
+#endif
+
 #if !defined(HAVE_REALPATH) || defined(BROKEN_REALPATH)
 /*
  * glibc's FORTIFY_SOURCE can redefine this and prevent us picking up the

openbsd-compat/recallocarray.c

@@ -0,0 +1,88 @@
+/*	$OpenBSD: recallocarray.c,v 1.1 2017/03/06 18:44:21 otto Exp $	*/
+/*
+ * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* OPENBSD ORIGINAL: lib/libc/stdlib/recallocarray.c */
+
+#include "includes.h"
+#ifndef HAVE_RECALLOCARRAY
+
+#include <errno.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+
+/*
+ * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
+ * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
+ */
+#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
+
+void *
+recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
+{
+	size_t oldsize, newsize;
+	void *newptr;
+
+	if (ptr == NULL)
+		return calloc(newnmemb, size);
+
+	if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
+	    newnmemb > 0 && SIZE_MAX / newnmemb < size) {
+		errno = ENOMEM;
+		return NULL;
+	}
+	newsize = newnmemb * size;
+
+	if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
+	    oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
+		errno = EINVAL;
+		return NULL;
+	}
+	oldsize = oldnmemb * size;
+	
+	/*
+	 * Don't bother too much if we're shrinking just a bit,
+	 * we do not shrink for series of small steps, oh well.
+	 */
+	if (newsize <= oldsize) {
+		size_t d = oldsize - newsize;
+
+		if (d < oldsize / 2 && d < getpagesize()) {
+			memset((char *)ptr + newsize, 0, d);
+			return ptr;
+		}
+	}
+
+	newptr = malloc(newsize);
+	if (newptr == NULL)
+		return NULL;
+
+	if (newsize > oldsize) {
+		memcpy(newptr, ptr, oldsize);
+		memset((char *)newptr + oldsize, 0, newsize - oldsize);
+	} else
+		memcpy(newptr, ptr, newsize);
+
+	explicit_bzero(ptr, oldsize);
+	free(ptr);
+
+	return newptr;
+}
+/* DEF_WEAK(recallocarray); */
+
+#endif /* HAVE_RECALLOCARRAY */