auto import from //depot/cupcake/@135843
diff --git a/sh/memalloc.c b/sh/memalloc.c
new file mode 100644
index 0000000..07c14db
--- /dev/null
+++ b/sh/memalloc.c
@@ -0,0 +1,307 @@
+/* $NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc Exp $ */
+
+/*-
+ * Copyright (c) 1991, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 THE REGENTS OR CONTRIBUTORS 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.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
+#else
+__RCSID("$NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc Exp $");
+#endif
+#endif /* not lint */
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "shell.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "machdep.h"
+#include "mystring.h"
+
+/*
+ * Like malloc, but returns an error when out of space.
+ */
+
+pointer
+ckmalloc(int nbytes)
+{
+ pointer p;
+
+ p = malloc(nbytes);
+ if (p == NULL)
+ error("Out of space");
+ return p;
+}
+
+
+/*
+ * Same for realloc.
+ */
+
+pointer
+ckrealloc(pointer p, int nbytes)
+{
+ p = realloc(p, nbytes);
+ if (p == NULL)
+ error("Out of space");
+ return p;
+}
+
+
+/*
+ * Make a copy of a string in safe storage.
+ */
+
+char *
+savestr(const char *s)
+{
+ char *p;
+
+ p = ckmalloc(strlen(s) + 1);
+ scopy(s, p);
+ return p;
+}
+
+
+/*
+ * Parse trees for commands are allocated in lifo order, so we use a stack
+ * to make this more efficient, and also to avoid all sorts of exception
+ * handling code to handle interrupts in the middle of a parse.
+ *
+ * The size 504 was chosen because the Ultrix malloc handles that size
+ * well.
+ */
+
+#define MINSIZE 504 /* minimum size of a block */
+
+struct stack_block {
+ struct stack_block *prev;
+ char space[MINSIZE];
+};
+
+struct stack_block stackbase;
+struct stack_block *stackp = &stackbase;
+struct stackmark *markp;
+char *stacknxt = stackbase.space;
+int stacknleft = MINSIZE;
+int sstrnleft;
+int herefd = -1;
+
+pointer
+stalloc(int nbytes)
+{
+ char *p;
+
+ nbytes = SHELL_ALIGN(nbytes);
+ if (nbytes > stacknleft) {
+ int blocksize;
+ struct stack_block *sp;
+
+ blocksize = nbytes;
+ if (blocksize < MINSIZE)
+ blocksize = MINSIZE;
+ INTOFF;
+ sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize);
+ sp->prev = stackp;
+ stacknxt = sp->space;
+ stacknleft = blocksize;
+ stackp = sp;
+ INTON;
+ }
+ p = stacknxt;
+ stacknxt += nbytes;
+ stacknleft -= nbytes;
+ return p;
+}
+
+
+void
+stunalloc(pointer p)
+{
+ if (p == NULL) { /*DEBUG */
+ write(2, "stunalloc\n", 10);
+ abort();
+ }
+ stacknleft += stacknxt - (char *)p;
+ stacknxt = p;
+}
+
+
+
+void
+setstackmark(struct stackmark *mark)
+{
+ mark->stackp = stackp;
+ mark->stacknxt = stacknxt;
+ mark->stacknleft = stacknleft;
+ mark->marknext = markp;
+ markp = mark;
+}
+
+
+void
+popstackmark(struct stackmark *mark)
+{
+ struct stack_block *sp;
+
+ INTOFF;
+ markp = mark->marknext;
+ while (stackp != mark->stackp) {
+ sp = stackp;
+ stackp = sp->prev;
+ ckfree(sp);
+ }
+ stacknxt = mark->stacknxt;
+ stacknleft = mark->stacknleft;
+ INTON;
+}
+
+
+/*
+ * When the parser reads in a string, it wants to stick the string on the
+ * stack and only adjust the stack pointer when it knows how big the
+ * string is. Stackblock (defined in stack.h) returns a pointer to a block
+ * of space on top of the stack and stackblocklen returns the length of
+ * this block. Growstackblock will grow this space by at least one byte,
+ * possibly moving it (like realloc). Grabstackblock actually allocates the
+ * part of the block that has been used.
+ */
+
+void
+growstackblock(void)
+{
+ int newlen = SHELL_ALIGN(stacknleft * 2 + 100);
+
+ if (stacknxt == stackp->space && stackp != &stackbase) {
+ struct stack_block *oldstackp;
+ struct stackmark *xmark;
+ struct stack_block *sp;
+
+ INTOFF;
+ oldstackp = stackp;
+ sp = stackp;
+ stackp = sp->prev;
+ sp = ckrealloc((pointer)sp,
+ sizeof(struct stack_block) - MINSIZE + newlen);
+ sp->prev = stackp;
+ stackp = sp;
+ stacknxt = sp->space;
+ stacknleft = newlen;
+
+ /*
+ * Stack marks pointing to the start of the old block
+ * must be relocated to point to the new block
+ */
+ xmark = markp;
+ while (xmark != NULL && xmark->stackp == oldstackp) {
+ xmark->stackp = stackp;
+ xmark->stacknxt = stacknxt;
+ xmark->stacknleft = stacknleft;
+ xmark = xmark->marknext;
+ }
+ INTON;
+ } else {
+ char *oldspace = stacknxt;
+ int oldlen = stacknleft;
+ char *p = stalloc(newlen);
+
+ (void)memcpy(p, oldspace, oldlen);
+ stacknxt = p; /* free the space */
+ stacknleft += newlen; /* we just allocated */
+ }
+}
+
+void
+grabstackblock(int len)
+{
+ len = SHELL_ALIGN(len);
+ stacknxt += len;
+ stacknleft -= len;
+}
+
+/*
+ * The following routines are somewhat easier to use than the above.
+ * The user declares a variable of type STACKSTR, which may be declared
+ * to be a register. The macro STARTSTACKSTR initializes things. Then
+ * the user uses the macro STPUTC to add characters to the string. In
+ * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
+ * grown as necessary. When the user is done, she can just leave the
+ * string there and refer to it using stackblock(). Or she can allocate
+ * the space for it using grabstackstr(). If it is necessary to allow
+ * someone else to use the stack temporarily and then continue to grow
+ * the string, the user should use grabstack to allocate the space, and
+ * then call ungrabstr(p) to return to the previous mode of operation.
+ *
+ * USTPUTC is like STPUTC except that it doesn't check for overflow.
+ * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
+ * is space for at least one character.
+ */
+
+char *
+growstackstr(void)
+{
+ int len = stackblocksize();
+ if (herefd >= 0 && len >= 1024) {
+ xwrite(herefd, stackblock(), len);
+ sstrnleft = len - 1;
+ return stackblock();
+ }
+ growstackblock();
+ sstrnleft = stackblocksize() - len - 1;
+ return stackblock() + len;
+}
+
+/*
+ * Called from CHECKSTRSPACE.
+ */
+
+char *
+makestrspace(void)
+{
+ int len = stackblocksize() - sstrnleft;
+ growstackblock();
+ sstrnleft = stackblocksize() - len;
+ return stackblock() + len;
+}
+
+void
+ungrabstackstr(char *s, char *p)
+{
+ stacknleft += stacknxt - s;
+ stacknxt = s;
+ sstrnleft = stacknleft - (p - s);
+
+}