1 /*-
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. 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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #ifndef lint
34 #if 0
35 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
36 #endif
37 #endif /* not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD: stable/9/bin/sh/memalloc.c 217209 2011-01-09 22:47:58Z jilles $");
40
41 #include <sys/param.h>
42 #include "shell.h"
43 #include "output.h"
44 #include "memalloc.h"
45 #include "error.h"
46 #include "mystring.h"
47 #include "expand.h"
48 #include <stdlib.h>
49 #include <unistd.h>
50
51 /*
52 * Like malloc, but returns an error when out of space.
53 */
54
55 pointer
ckmalloc(size_t nbytes)56 ckmalloc(size_t nbytes)
57 {
58 pointer p;
59
60 INTOFF;
61 p = malloc(nbytes);
62 INTON;
63 if (p == NULL)
64 error("Out of space");
65 return p;
66 }
67
68
69 /*
70 * Same for realloc.
71 */
72
73 pointer
ckrealloc(pointer p,int nbytes)74 ckrealloc(pointer p, int nbytes)
75 {
76 INTOFF;
77 p = realloc(p, nbytes);
78 INTON;
79 if (p == NULL)
80 error("Out of space");
81 return p;
82 }
83
84 void
ckfree(pointer p)85 ckfree(pointer p)
86 {
87 INTOFF;
88 free(p);
89 INTON;
90 }
91
92
93 /*
94 * Make a copy of a string in safe storage.
95 */
96
97 char *
savestr(const char * s)98 savestr(const char *s)
99 {
100 char *p;
101
102 p = ckmalloc(strlen(s) + 1);
103 scopy(s, p);
104 return p;
105 }
106
107
108 /*
109 * Parse trees for commands are allocated in lifo order, so we use a stack
110 * to make this more efficient, and also to avoid all sorts of exception
111 * handling code to handle interrupts in the middle of a parse.
112 *
113 * The size 496 was chosen because with 16-byte alignment the total size
114 * for the allocated block is 512.
115 */
116
117 #define MINSIZE 496 /* minimum size of a block. */
118
119
120 struct stack_block {
121 struct stack_block *prev;
122 /* Data follows */
123 };
124 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
125
126 static struct stack_block *stackp;
127 static struct stackmark *markp;
128 char *stacknxt;
129 int stacknleft;
130 char *sstrend;
131
132
133 static void
stnewblock(int nbytes)134 stnewblock(int nbytes)
135 {
136 struct stack_block *sp;
137 int allocsize;
138
139 if (nbytes < MINSIZE)
140 nbytes = MINSIZE;
141
142 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
143
144 INTOFF;
145 sp = ckmalloc(allocsize);
146 sp->prev = stackp;
147 stacknxt = SPACE(sp);
148 stacknleft = allocsize - (stacknxt - (char*)sp);
149 sstrend = stacknxt + stacknleft;
150 stackp = sp;
151 INTON;
152 }
153
154
155 pointer
stalloc(int nbytes)156 stalloc(int nbytes)
157 {
158 char *p;
159
160 nbytes = ALIGN(nbytes);
161 if (nbytes > stacknleft)
162 stnewblock(nbytes);
163 p = stacknxt;
164 stacknxt += nbytes;
165 stacknleft -= nbytes;
166 return p;
167 }
168
169
170 void
stunalloc(pointer p)171 stunalloc(pointer p)
172 {
173 if (p == NULL) { /*DEBUG */
174 write(STDERR_FILENO, "stunalloc\n", 10);
175 abort();
176 }
177 stacknleft += stacknxt - (char *)p;
178 stacknxt = p;
179 }
180
181
182
183 void
setstackmark(struct stackmark * mark)184 setstackmark(struct stackmark *mark)
185 {
186 mark->stackp = stackp;
187 mark->stacknxt = stacknxt;
188 mark->stacknleft = stacknleft;
189 mark->marknext = markp;
190 markp = mark;
191 }
192
193
194 void
popstackmark(struct stackmark * mark)195 popstackmark(struct stackmark *mark)
196 {
197 struct stack_block *sp;
198
199 INTOFF;
200 markp = mark->marknext;
201 while (stackp != mark->stackp) {
202 sp = stackp;
203 stackp = sp->prev;
204 ckfree(sp);
205 }
206 stacknxt = mark->stacknxt;
207 stacknleft = mark->stacknleft;
208 sstrend = stacknxt + stacknleft;
209 INTON;
210 }
211
212
213 /*
214 * When the parser reads in a string, it wants to stick the string on the
215 * stack and only adjust the stack pointer when it knows how big the
216 * string is. Stackblock (defined in stack.h) returns a pointer to a block
217 * of space on top of the stack and stackblocklen returns the length of
218 * this block. Growstackblock will grow this space by at least one byte,
219 * possibly moving it (like realloc). Grabstackblock actually allocates the
220 * part of the block that has been used.
221 */
222
223 static void
growstackblock(int min)224 growstackblock(int min)
225 {
226 char *p;
227 int newlen;
228 char *oldspace;
229 int oldlen;
230 struct stack_block *sp;
231 struct stack_block *oldstackp;
232 struct stackmark *xmark;
233
234 if (min < stacknleft)
235 min = stacknleft;
236 if (min >= INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
237 error("Out of space");
238 min += stacknleft;
239 min += ALIGN(sizeof(struct stack_block));
240 newlen = 512;
241 while (newlen < min)
242 newlen <<= 1;
243 oldspace = stacknxt;
244 oldlen = stacknleft;
245
246 if (stackp != NULL && stacknxt == SPACE(stackp)) {
247 INTOFF;
248 oldstackp = stackp;
249 stackp = oldstackp->prev;
250 sp = ckrealloc((pointer)oldstackp, newlen);
251 sp->prev = stackp;
252 stackp = sp;
253 stacknxt = SPACE(sp);
254 stacknleft = newlen - (stacknxt - (char*)sp);
255 sstrend = stacknxt + stacknleft;
256
257 /*
258 * Stack marks pointing to the start of the old block
259 * must be relocated to point to the new block
260 */
261 xmark = markp;
262 while (xmark != NULL && xmark->stackp == oldstackp) {
263 xmark->stackp = stackp;
264 xmark->stacknxt = stacknxt;
265 xmark->stacknleft = stacknleft;
266 xmark = xmark->marknext;
267 }
268 INTON;
269 } else {
270 newlen -= ALIGN(sizeof(struct stack_block));
271 p = stalloc(newlen);
272 if (oldlen != 0)
273 memcpy(p, oldspace, oldlen);
274 stunalloc(p);
275 }
276 }
277
278
279
280 /*
281 * The following routines are somewhat easier to use that the above.
282 * The user declares a variable of type STACKSTR, which may be declared
283 * to be a register. The macro STARTSTACKSTR initializes things. Then
284 * the user uses the macro STPUTC to add characters to the string. In
285 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
286 * grown as necessary. When the user is done, she can just leave the
287 * string there and refer to it using stackblock(). Or she can allocate
288 * the space for it using grabstackstr(). If it is necessary to allow
289 * someone else to use the stack temporarily and then continue to grow
290 * the string, the user should use grabstack to allocate the space, and
291 * then call ungrabstr(p) to return to the previous mode of operation.
292 *
293 * USTPUTC is like STPUTC except that it doesn't check for overflow.
294 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
295 * is space for at least one character.
296 */
297
298 static char *
growstrstackblock(int n,int min)299 growstrstackblock(int n, int min)
300 {
301 growstackblock(min);
302 return stackblock() + n;
303 }
304
305 char *
growstackstr(void)306 growstackstr(void)
307 {
308 int len;
309
310 len = stackblocksize();
311 return (growstrstackblock(len, 0));
312 }
313
314
315 /*
316 * Called from CHECKSTRSPACE.
317 */
318
319 char *
makestrspace(int min,char * p)320 makestrspace(int min, char *p)
321 {
322 int len;
323
324 len = p - stackblock();
325 return (growstrstackblock(len, min));
326 }
327
328
329 char *
stputbin(const char * data,int len,char * p)330 stputbin(const char *data, int len, char *p)
331 {
332 CHECKSTRSPACE(len, p);
333 memcpy(p, data, len);
334 return (p + len);
335 }
336
337 char *
stputs(const char * data,char * p)338 stputs(const char *data, char *p)
339 {
340 return (stputbin(data, strlen(data), p));
341 }
342