1 files changed, 302 insertions, 0 deletions
diff --git a/usr/dash/memalloc.c b/usr/dash/memalloc.c
new file mode 100644
index 0000000..d8e4413
--- /dev/null
+++ b/usr/dash/memalloc.c
@@ -0,0 +1,302 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1997-2005
+ *	Herbert Xu <herbert@gondor.apana.org.au>.  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 <stdlib.h>
+#include <unistd.h>
+
+#include "shell.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "machdep.h"
+#include "mystring.h"
+#include "system.h"
+
+/*
+ * Like malloc, but returns an error when out of space.
+ */
+
+pointer
+ckmalloc(size_t nbytes)
+{
+	pointer p;
+
+	p = malloc(nbytes);
+	if (p == NULL)
+		sh_error("Out of space");
+	return p;
+}
+
+
+/*
+ * Same for realloc.
+ */
+
+pointer
+ckrealloc(pointer p, size_t nbytes)
+{
+	p = realloc(p, nbytes);
+	if (p == NULL)
+		sh_error("Out of space");
+	return p;
+}
+
+
+/*
+ * Make a copy of a string in safe storage.
+ */
+
+char *
+savestr(const char *s)
+{
+	char *p = strdup(s);
+	if (!p)
+		sh_error("Out of space");
+	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.
+ */
+
+/* minimum size of a block */
+#define MINSIZE SHELL_ALIGN(504)
+
+struct stack_block {
+	struct stack_block *prev;
+	char space[MINSIZE];
+};
+
+struct stack_block stackbase;
+struct stack_block *stackp = &stackbase;
+char *stacknxt = stackbase.space;
+size_t stacknleft = MINSIZE;
+char *sstrend = stackbase.space + MINSIZE;
+
+pointer
+stalloc(size_t nbytes)
+{
+	char *p;
+	size_t aligned;
+
+	aligned = SHELL_ALIGN(nbytes);
+	if (aligned > stacknleft) {
+		size_t len;
+		size_t blocksize;
+		struct stack_block *sp;
+
+		blocksize = aligned;
+		if (blocksize < MINSIZE)
+			blocksize = MINSIZE;
+		len = sizeof(struct stack_block) - MINSIZE + blocksize;
+		if (len < blocksize)
+			sh_error("Out of space");
+		INTOFF;
+		sp = ckmalloc(len);
+		sp->prev = stackp;
+		stacknxt = sp->space;
+		stacknleft = blocksize;
+		sstrend = stacknxt + blocksize;
+		stackp = sp;
+		INTON;
+	}
+	p = stacknxt;
+	stacknxt += aligned;
+	stacknleft -= aligned;
+	return p;
+}
+
+
+void
+stunalloc(pointer p)
+{
+#ifdef DEBUG
+	if (!p || (stacknxt < (char *)p) || ((char *)p < stackp->space)) {
+		write(2, "stunalloc\n", 10);
+		abort();
+	}
+#endif
+	stacknleft += stacknxt - (char *)p;
+	stacknxt = p;
+}
+
+
+
+void pushstackmark(struct stackmark *mark, size_t len)
+{
+	mark->stackp = stackp;
+	mark->stacknxt = stacknxt;
+	mark->stacknleft = stacknleft;
+	grabstackblock(len);
+}
+
+void setstackmark(struct stackmark *mark)
+{
+	pushstackmark(mark, stacknxt == stackp->space && stackp != &stackbase);
+}
+
+
+void
+popstackmark(struct stackmark *mark)
+{
+	struct stack_block *sp;
+
+	INTOFF;
+	while (stackp != mark->stackp) {
+		sp = stackp;
+		stackp = sp->prev;
+		ckfree(sp);
+	}
+	stacknxt = mark->stacknxt;
+	stacknleft = mark->stacknleft;
+	sstrend = mark->stacknxt + 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)
+{
+	size_t newlen;
+
+	newlen = stacknleft * 2;
+	if (newlen < stacknleft)
+		sh_error("Out of space");
+	if (newlen < 128)
+		newlen += 128;
+
+	if (stacknxt == stackp->space && stackp != &stackbase) {
+		struct stack_block *sp;
+		struct stack_block *prevstackp;
+		size_t grosslen;
+
+		INTOFF;
+		sp = stackp;
+		prevstackp = sp->prev;
+		grosslen = newlen + sizeof(struct stack_block) - MINSIZE;
+		sp = ckrealloc((pointer)sp, grosslen);
+		sp->prev = prevstackp;
+		stackp = sp;
+		stacknxt = sp->space;
+		stacknleft = newlen;
+		sstrend = sp->space + newlen;
+		INTON;
+	} else {
+		char *oldspace = stacknxt;
+		int oldlen = stacknleft;
+		char *p = stalloc(newlen);
+
+		/* free the space we just allocated */
+		stacknxt = memcpy(p, oldspace, oldlen);
+		stacknleft += newlen;
+	}
+}
+
+/*
+ * 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.
+ */
+
+void *
+growstackstr(void)
+{
+	size_t len = stackblocksize();
+	growstackblock();
+	return stackblock() + len;
+}
+
+/*
+ * Called from CHECKSTRSPACE.
+ */
+
+char *
+makestrspace(size_t newlen, char *p)
+{
+	size_t len = p - stacknxt;
+	size_t size;
+
+	for (;;) {
+		size_t nleft;
+
+		size = stackblocksize();
+		nleft = size - len;
+		if (nleft >= newlen)
+			break;
+		growstackblock();
+	}
+	return stackblock() + len;
+}
+
+char *
+stnputs(const char *s, size_t n, char *p)
+{
+	p = makestrspace(n, p);
+	p = mempcpy(p, s, n);
+	return p;
+}
+
+char *
+stputs(const char *s, char *p)
+{
+	return stnputs(s, strlen(s), p);
+}