usr/dash/memalloc.c

/*-
 * 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;
struct stackmark *markp;
char *stacknxt = stackbase.space;
size_t stacknleft = MINSIZE;
char *sstrend = stackbase.space + MINSIZE;
int herefd = -1;

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
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;
	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 *oldstackp;
		struct stackmark *xmark;
		struct stack_block *sp;
		struct stack_block *prevstackp;
		size_t grosslen;

		INTOFF;
		oldstackp = stackp;
		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;

		/*
		 * 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);

		/* free the space we just allocated */
		stacknxt = memcpy(p, oldspace, oldlen);
		stacknleft += newlen;
	}
}

void
grabstackblock(size_t 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.
 */

void *
growstackstr(void)
{
	size_t len = stackblocksize();
	if (herefd >= 0 && len >= 1024) {
		xwrite(herefd, stackblock(), len);
		return stackblock();
	}
	growstackblock();
	return stackblock() + len;
}

/*
 * Called from CHECKSTRSPACE.
 */

char *
makestrspace(size_t newlen, char *p)
{
	size_t len = p - stacknxt;
	size_t size = stackblocksize();

	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);
}
1	/*-
2	* Copyright (c) 1991, 1993
3	* The Regents of the University of California. All rights reserved.
4	* Copyright (c) 1997-2005
5	* Herbert Xu <herbert@gondor.apana.org.au>. All rights reserved.
6	*
7	* This code is derived from software contributed to Berkeley by
8	* Kenneth Almquist.
9	*
10	* Redistribution and use in source and binary forms, with or without
11	* modification, are permitted provided that the following conditions
12	* are met:
13	* 1. Redistributions of source code must retain the above copyright
14	* notice, this list of conditions and the following disclaimer.
15	* 2. Redistributions in binary form must reproduce the above copyright
16	* notice, this list of conditions and the following disclaimer in the
17	* documentation and/or other materials provided with the distribution.
18	* 3. Neither the name of the University nor the names of its contributors
19	* may be used to endorse or promote products derived from this software
20	* without specific prior written permission.
21	*
22	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32	* SUCH DAMAGE.
33	*/
34
35	#include <stdlib.h>
36	#include <unistd.h>
37
38	#include "shell.h"
39	#include "output.h"
40	#include "memalloc.h"
41	#include "error.h"
42	#include "machdep.h"
43	#include "mystring.h"
44	#include "system.h"
45
46	/*
47	* Like malloc, but returns an error when out of space.
48	*/
49
50	pointer
51	ckmalloc(size_t nbytes)
52	{
53	pointer p;
54
55	p = malloc(nbytes);
56	if (p == NULL)
57	sh_error("Out of space");
58	return p;
59	}
60
61
62	/*
63	* Same for realloc.
64	*/
65
66	pointer
67	ckrealloc(pointer p, size_t nbytes)
68	{
69	p = realloc(p, nbytes);
70	if (p == NULL)
71	sh_error("Out of space");
72	return p;
73	}
74
75
76	/*
77	* Make a copy of a string in safe storage.
78	*/
79
80	char *
81	savestr(const char *s)
82	{
83	char *p = strdup(s);
84	if (!p)
85	sh_error("Out of space");
86	return p;
87	}
88
89
90	/*
91	* Parse trees for commands are allocated in lifo order, so we use a stack
92	* to make this more efficient, and also to avoid all sorts of exception
93	* handling code to handle interrupts in the middle of a parse.
94	*
95	* The size 504 was chosen because the Ultrix malloc handles that size
96	* well.
97	*/
98
99	/* minimum size of a block */
100	#define MINSIZE SHELL_ALIGN(504)
101
102	struct stack_block {
103	struct stack_block *prev;
104	char space[MINSIZE];
105	};
106
107	struct stack_block stackbase;
108	struct stack_block *stackp = &stackbase;
109	struct stackmark *markp;
110	char *stacknxt = stackbase.space;
111	size_t stacknleft = MINSIZE;
112	char *sstrend = stackbase.space + MINSIZE;
113	int herefd = -1;
114
115	pointer
116	stalloc(size_t nbytes)
117	{
118	char *p;
119	size_t aligned;
120
121	aligned = SHELL_ALIGN(nbytes);
122	if (aligned > stacknleft) {
123	size_t len;
124	size_t blocksize;
125	struct stack_block *sp;
126
127	blocksize = aligned;
128	if (blocksize < MINSIZE)
129	blocksize = MINSIZE;
130	len = sizeof(struct stack_block) - MINSIZE + blocksize;
131	if (len < blocksize)
132	sh_error("Out of space");
133	INTOFF;
134	sp = ckmalloc(len);
135	sp->prev = stackp;
136	stacknxt = sp->space;
137	stacknleft = blocksize;
138	sstrend = stacknxt + blocksize;
139	stackp = sp;
140	INTON;
141	}
142	p = stacknxt;
143	stacknxt += aligned;
144	stacknleft -= aligned;
145	return p;
146	}
147
148
149	void
150	stunalloc(pointer p)
151	{
152	#ifdef DEBUG
153	if (!p \|\| (stacknxt < (char )p) \|\| ((char )p < stackp->space)) {
154	write(2, "stunalloc\n", 10);
155	abort();
156	}
157	#endif
158	stacknleft += stacknxt - (char *)p;
159	stacknxt = p;
160	}
161
162
163
164	void
165	setstackmark(struct stackmark *mark)
166	{
167	mark->stackp = stackp;
168	mark->stacknxt = stacknxt;
169	mark->stacknleft = stacknleft;
170	mark->marknext = markp;
171	markp = mark;
172	}
173
174
175	void
176	popstackmark(struct stackmark *mark)
177	{
178	struct stack_block *sp;
179
180	INTOFF;
181	markp = mark->marknext;
182	while (stackp != mark->stackp) {
183	sp = stackp;
184	stackp = sp->prev;
185	ckfree(sp);
186	}
187	stacknxt = mark->stacknxt;
188	stacknleft = mark->stacknleft;
189	sstrend = mark->stacknxt + mark->stacknleft;
190	INTON;
191	}
192
193
194	/*
195	* When the parser reads in a string, it wants to stick the string on the
196	* stack and only adjust the stack pointer when it knows how big the
197	* string is. Stackblock (defined in stack.h) returns a pointer to a block
198	* of space on top of the stack and stackblocklen returns the length of
199	* this block. Growstackblock will grow this space by at least one byte,
200	* possibly moving it (like realloc). Grabstackblock actually allocates the
201	* part of the block that has been used.
202	*/
203
204	void
205	growstackblock(void)
206	{
207	size_t newlen;
208
209	newlen = stacknleft * 2;
210	if (newlen < stacknleft)
211	sh_error("Out of space");
212	if (newlen < 128)
213	newlen += 128;
214
215	if (stacknxt == stackp->space && stackp != &stackbase) {
216	struct stack_block *oldstackp;
217	struct stackmark *xmark;
218	struct stack_block *sp;
219	struct stack_block *prevstackp;
220	size_t grosslen;
221
222	INTOFF;
223	oldstackp = stackp;
224	sp = stackp;
225	prevstackp = sp->prev;
226	grosslen = newlen + sizeof(struct stack_block) - MINSIZE;
227	sp = ckrealloc((pointer)sp, grosslen);
228	sp->prev = prevstackp;
229	stackp = sp;
230	stacknxt = sp->space;
231	stacknleft = newlen;
232	sstrend = sp->space + newlen;
233
234	/*
235	* Stack marks pointing to the start of the old block
236	* must be relocated to point to the new block
237	*/
238	xmark = markp;
239	while (xmark != NULL && xmark->stackp == oldstackp) {
240	xmark->stackp = stackp;
241	xmark->stacknxt = stacknxt;
242	xmark->stacknleft = stacknleft;
243	xmark = xmark->marknext;
244	}
245	INTON;
246	} else {
247	char *oldspace = stacknxt;
248	int oldlen = stacknleft;
249	char *p = stalloc(newlen);
250
251	/* free the space we just allocated */
252	stacknxt = memcpy(p, oldspace, oldlen);
253	stacknleft += newlen;
254	}
255	}
256
257	void
258	grabstackblock(size_t len)
259	{
260	len = SHELL_ALIGN(len);
261	stacknxt += len;
262	stacknleft -= len;
263	}
264
265	/*
266	* The following routines are somewhat easier to use than the above.
267	* The user declares a variable of type STACKSTR, which may be declared
268	* to be a register. The macro STARTSTACKSTR initializes things. Then
269	* the user uses the macro STPUTC to add characters to the string. In
270	* effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
271	* grown as necessary. When the user is done, she can just leave the
272	* string there and refer to it using stackblock(). Or she can allocate
273	* the space for it using grabstackstr(). If it is necessary to allow
274	* someone else to use the stack temporarily and then continue to grow
275	* the string, the user should use grabstack to allocate the space, and
276	* then call ungrabstr(p) to return to the previous mode of operation.
277	*
278	* USTPUTC is like STPUTC except that it doesn't check for overflow.
279	* CHECKSTACKSPACE can be called before USTPUTC to ensure that there
280	* is space for at least one character.
281	*/
282
283	void *
284	growstackstr(void)
285	{
286	size_t len = stackblocksize();
287	if (herefd >= 0 && len >= 1024) {
288	xwrite(herefd, stackblock(), len);
289	return stackblock();
290	}
291	growstackblock();
292	return stackblock() + len;
293	}
294
295	/*
296	* Called from CHECKSTRSPACE.
297	*/
298
299	char *
300	makestrspace(size_t newlen, char *p)
301	{
302	size_t len = p - stacknxt;
303	size_t size = stackblocksize();
304
305	for (;;) {
306	size_t nleft;
307
308	size = stackblocksize();
309	nleft = size - len;
310	if (nleft >= newlen)
311	break;
312	growstackblock();
313	}
314	return stackblock() + len;
315	}
316
317	char *
318	stnputs(const char s, size_t n, char p)
319	{
320	p = makestrspace(n, p);
321	p = mempcpy(p, s, n);
322	return p;
323	}
324
325	char *
326	stputs(const char s, char p)
327	{
328	return stnputs(s, strlen(s), p);
329	}