1 /*-
2 * Copyright (c) 1991 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #ifndef lint
38 static char sccsid[] = "@(#)memalloc.c 5.2 (Berkeley) 3/13/91";
39 #endif /* not lint */
40
41 #include "shell.h"
42 #include "output.h"
43 #include "memalloc.h"
44 #include "error.h"
45 #include "machdep.h"
46 #include "mystring.h"
47
48 /*
49 * Like malloc, but returns an error when out of space.
50 */
51
52 pointer
ckmalloc(nbytes)53 ckmalloc(nbytes) {
54 register pointer p;
55 pointer malloc();
56
57 if ((p = malloc(nbytes)) == NULL)
58 error("Out of space");
59 return p;
60 }
61
62
63 /*
64 * Same for realloc.
65 */
66
67 pointer
ckrealloc(p,nbytes)68 ckrealloc(p, nbytes)
69 register pointer p;
70 {
71 pointer realloc();
72
73 if ((p = realloc(p, nbytes)) == NULL)
74 error("Out of space");
75 return p;
76 }
77
78
79 /*
80 * Make a copy of a string in safe storage.
81 */
82
83 char *
savestr(s)84 savestr(s)
85 char *s;
86 {
87 register char *p;
88
89 p = ckmalloc(strlen(s) + 1);
90 scopy(s, p);
91 return p;
92 }
93
94
95 /*
96 * Parse trees for commands are allocated in lifo order, so we use a stack
97 * to make this more efficient, and also to avoid all sorts of exception
98 * handling code to handle interrupts in the middle of a parse.
99 *
100 * The size 504 was chosen because the Ultrix malloc handles that size
101 * well.
102 */
103
104 #define MINSIZE 504 /* minimum size of a block */
105
106
107 struct stack_block {
108 struct stack_block *prev;
109 char space[MINSIZE];
110 };
111
112 struct stack_block stackbase;
113 struct stack_block *stackp = &stackbase;
114 char *stacknxt = stackbase.space;
115 int stacknleft = MINSIZE;
116 int sstrnleft;
117 int herefd = -1;
118
119
120
121 pointer
stalloc(nbytes)122 stalloc(nbytes) {
123 register char *p;
124
125 nbytes = ALIGN(nbytes);
126 if (nbytes > stacknleft) {
127 int blocksize;
128 struct stack_block *sp;
129
130 blocksize = nbytes;
131 if (blocksize < MINSIZE)
132 blocksize = MINSIZE;
133 INTOFF;
134 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize);
135 sp->prev = stackp;
136 stacknxt = sp->space;
137 stacknleft = blocksize;
138 stackp = sp;
139 INTON;
140 }
141 p = stacknxt;
142 stacknxt += nbytes;
143 stacknleft -= nbytes;
144 return p;
145 }
146
147
148 void
stunalloc(p)149 stunalloc(p)
150 pointer p;
151 {
152 if (p == NULL) { /*DEBUG */
153 write(2, "stunalloc\n", 10);
154 abort();
155 }
156 stacknleft += stacknxt - (char *)p;
157 stacknxt = p;
158 }
159
160
161
162 void
setstackmark(mark)163 setstackmark(mark)
164 struct stackmark *mark;
165 {
166 mark->stackp = stackp;
167 mark->stacknxt = stacknxt;
168 mark->stacknleft = stacknleft;
169 }
170
171
172 void
popstackmark(mark)173 popstackmark(mark)
174 struct stackmark *mark;
175 {
176 struct stack_block *sp;
177
178 INTOFF;
179 while (stackp != mark->stackp) {
180 sp = stackp;
181 stackp = sp->prev;
182 ckfree(sp);
183 }
184 stacknxt = mark->stacknxt;
185 stacknleft = mark->stacknleft;
186 INTON;
187 }
188
189
190 /*
191 * When the parser reads in a string, it wants to stick the string on the
192 * stack and only adjust the stack pointer when it knows how big the
193 * string is. Stackblock (defined in stack.h) returns a pointer to a block
194 * of space on top of the stack and stackblocklen returns the length of
195 * this block. Growstackblock will grow this space by at least one byte,
196 * possibly moving it (like realloc). Grabstackblock actually allocates the
197 * part of the block that has been used.
198 */
199
200 void
growstackblock()201 growstackblock() {
202 char *p;
203 int newlen = stacknleft * 2 + 100;
204 char *oldspace = stacknxt;
205 int oldlen = stacknleft;
206 struct stack_block *sp;
207
208 if (stacknxt == stackp->space && stackp != &stackbase) {
209 INTOFF;
210 sp = stackp;
211 stackp = sp->prev;
212 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen);
213 sp->prev = stackp;
214 stackp = sp;
215 stacknxt = sp->space;
216 stacknleft = newlen;
217 INTON;
218 } else {
219 p = stalloc(newlen);
220 bcopy(oldspace, p, oldlen);
221 stacknxt = p; /* free the space */
222 stacknleft += newlen; /* we just allocated */
223 }
224 }
225
226
227
228 void
grabstackblock(len)229 grabstackblock(len) {
230 len = ALIGN(len);
231 stacknxt += len;
232 stacknleft -= len;
233 }
234
235
236
237 /*
238 * The following routines are somewhat easier to use that the above.
239 * The user declares a variable of type STACKSTR, which may be declared
240 * to be a register. The macro STARTSTACKSTR initializes things. Then
241 * the user uses the macro STPUTC to add characters to the string. In
242 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
243 * grown as necessary. When the user is done, she can just leave the
244 * string there and refer to it using stackblock(). Or she can allocate
245 * the space for it using grabstackstr(). If it is necessary to allow
246 * someone else to use the stack temporarily and then continue to grow
247 * the string, the user should use grabstack to allocate the space, and
248 * then call ungrabstr(p) to return to the previous mode of operation.
249 *
250 * USTPUTC is like STPUTC except that it doesn't check for overflow.
251 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
252 * is space for at least one character.
253 */
254
255
256 char *
growstackstr()257 growstackstr() {
258 int len = stackblocksize();
259 if (herefd >= 0 && len >= 1024) {
260 xwrite(herefd, stackblock(), len);
261 sstrnleft = len - 1;
262 return stackblock();
263 }
264 growstackblock();
265 sstrnleft = stackblocksize() - len - 1;
266 return stackblock() + len;
267 }
268
269
270 /*
271 * Called from CHECKSTRSPACE.
272 */
273
274 char *
makestrspace()275 makestrspace() {
276 int len = stackblocksize() - sstrnleft;
277 growstackblock();
278 sstrnleft = stackblocksize() - len;
279 return stackblock() + len;
280 }
281
282
283
284 void
ungrabstackstr(s,p)285 ungrabstackstr(s, p)
286 char *s;
287 char *p;
288 {
289 stacknleft += stacknxt - s;
290 stacknxt = s;
291 sstrnleft = stacknleft - (p - s);
292 }
293