1 /* $NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc Exp $ */
2
3 /*-
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. 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 <sys/cdefs.h>
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
39 #else
40 __RCSID("$NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc Exp $");
41 #endif
42 #endif /* not lint */
43
44 #include <stdlib.h>
45 #include <unistd.h>
46
47 #include "shell.h"
48 #include "output.h"
49 #include "memalloc.h"
50 #include "error.h"
51 #include "machdep.h"
52 #include "mystring.h"
53
54 /*
55 * Like malloc, but returns an error when out of space.
56 */
57
58 pointer
ckmalloc(int nbytes)59 ckmalloc(int nbytes)
60 {
61 pointer p;
62
63 p = malloc(nbytes);
64 if (p == NULL)
65 error("Out of space");
66 return p;
67 }
68
69
70 /*
71 * Same for realloc.
72 */
73
74 pointer
ckrealloc(pointer p,int nbytes)75 ckrealloc(pointer p, int nbytes)
76 {
77 p = realloc(p, nbytes);
78 if (p == NULL)
79 error("Out of space");
80 return p;
81 }
82
83
84 /*
85 * Make a copy of a string in safe storage.
86 */
87
88 char *
savestr(const char * s)89 savestr(const char *s)
90 {
91 char *p;
92
93 p = ckmalloc(strlen(s) + 1);
94 scopy(s, p);
95 return p;
96 }
97
98
99 /*
100 * Parse trees for commands are allocated in lifo order, so we use a stack
101 * to make this more efficient, and also to avoid all sorts of exception
102 * handling code to handle interrupts in the middle of a parse.
103 *
104 * The size 504 was chosen because the Ultrix malloc handles that size
105 * well.
106 */
107
108 #define MINSIZE 504 /* minimum size of a block */
109
110 struct stack_block {
111 struct stack_block *prev;
112 char space[MINSIZE];
113 };
114
115 struct stack_block stackbase;
116 struct stack_block *stackp = &stackbase;
117 struct stackmark *markp;
118 char *stacknxt = stackbase.space;
119 int stacknleft = MINSIZE;
120 int sstrnleft;
121 int herefd = -1;
122
123 pointer
stalloc(int nbytes)124 stalloc(int nbytes)
125 {
126 char *p;
127
128 nbytes = SHELL_ALIGN(nbytes);
129 if (nbytes > stacknleft) {
130 int blocksize;
131 struct stack_block *sp;
132
133 blocksize = nbytes;
134 if (blocksize < MINSIZE)
135 blocksize = MINSIZE;
136 INTOFF;
137 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize);
138 sp->prev = stackp;
139 stacknxt = sp->space;
140 stacknleft = blocksize;
141 stackp = sp;
142 INTON;
143 }
144 p = stacknxt;
145 stacknxt += nbytes;
146 stacknleft -= nbytes;
147 return p;
148 }
149
150
151 void
stunalloc(pointer p)152 stunalloc(pointer p)
153 {
154 if (p == NULL) { /*DEBUG */
155 write(2, "stunalloc\n", 10);
156 abort();
157 }
158 stacknleft += stacknxt - (char *)p;
159 stacknxt = p;
160 }
161
162
163
164 void
setstackmark(struct stackmark * mark)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
popstackmark(struct stackmark * mark)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 INTON;
190 }
191
192
193 /*
194 * When the parser reads in a string, it wants to stick the string on the
195 * stack and only adjust the stack pointer when it knows how big the
196 * string is. Stackblock (defined in stack.h) returns a pointer to a block
197 * of space on top of the stack and stackblocklen returns the length of
198 * this block. Growstackblock will grow this space by at least one byte,
199 * possibly moving it (like realloc). Grabstackblock actually allocates the
200 * part of the block that has been used.
201 */
202
203 void
growstackblock(void)204 growstackblock(void)
205 {
206 int newlen = SHELL_ALIGN(stacknleft * 2 + 100);
207
208 if (stacknxt == stackp->space && stackp != &stackbase) {
209 struct stack_block *oldstackp;
210 struct stackmark *xmark;
211 struct stack_block *sp;
212
213 INTOFF;
214 oldstackp = stackp;
215 sp = stackp;
216 stackp = sp->prev;
217 sp = ckrealloc((pointer)sp,
218 sizeof(struct stack_block) - MINSIZE + newlen);
219 sp->prev = stackp;
220 stackp = sp;
221 stacknxt = sp->space;
222 stacknleft = newlen;
223
224 /*
225 * Stack marks pointing to the start of the old block
226 * must be relocated to point to the new block
227 */
228 xmark = markp;
229 while (xmark != NULL && xmark->stackp == oldstackp) {
230 xmark->stackp = stackp;
231 xmark->stacknxt = stacknxt;
232 xmark->stacknleft = stacknleft;
233 xmark = xmark->marknext;
234 }
235 INTON;
236 } else {
237 char *oldspace = stacknxt;
238 int oldlen = stacknleft;
239 char *p = stalloc(newlen);
240
241 (void)memcpy(p, oldspace, oldlen);
242 stacknxt = p; /* free the space */
243 stacknleft += newlen; /* we just allocated */
244 }
245 }
246
247 void
grabstackblock(int len)248 grabstackblock(int len)
249 {
250 len = SHELL_ALIGN(len);
251 stacknxt += len;
252 stacknleft -= len;
253 }
254
255 /*
256 * The following routines are somewhat easier to use than the above.
257 * The user declares a variable of type STACKSTR, which may be declared
258 * to be a register. The macro STARTSTACKSTR initializes things. Then
259 * the user uses the macro STPUTC to add characters to the string. In
260 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
261 * grown as necessary. When the user is done, she can just leave the
262 * string there and refer to it using stackblock(). Or she can allocate
263 * the space for it using grabstackstr(). If it is necessary to allow
264 * someone else to use the stack temporarily and then continue to grow
265 * the string, the user should use grabstack to allocate the space, and
266 * then call ungrabstr(p) to return to the previous mode of operation.
267 *
268 * USTPUTC is like STPUTC except that it doesn't check for overflow.
269 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
270 * is space for at least one character.
271 */
272
273 char *
growstackstr(void)274 growstackstr(void)
275 {
276 int len = stackblocksize();
277 if (herefd >= 0 && len >= 1024) {
278 xwrite(herefd, stackblock(), len);
279 sstrnleft = len - 1;
280 return stackblock();
281 }
282 growstackblock();
283 sstrnleft = stackblocksize() - len - 1;
284 return stackblock() + len;
285 }
286
287 /*
288 * Called from CHECKSTRSPACE.
289 */
290
291 char *
makestrspace(void)292 makestrspace(void)
293 {
294 int len = stackblocksize() - sstrnleft;
295 growstackblock();
296 sstrnleft = stackblocksize() - len;
297 return stackblock() + len;
298 }
299
300 void
ungrabstackstr(char * s,char * p)301 ungrabstackstr(char *s, char *p)
302 {
303 stacknleft += stacknxt - s;
304 stacknxt = s;
305 sstrnleft = stacknleft - (p - s);
306
307 }
308