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("$FreeBSD$");
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 size_t len;
102
103 len = strlen(s);
104 p = ckmalloc(len + 1);
105 memcpy(p, s, len + 1);
106 return p;
107 }
108
109
110 /*
111 * Parse trees for commands are allocated in lifo order, so we use a stack
112 * to make this more efficient, and also to avoid all sorts of exception
113 * handling code to handle interrupts in the middle of a parse.
114 *
115 * The size 496 was chosen because with 16-byte alignment the total size
116 * for the allocated block is 512.
117 */
118
119 #define MINSIZE 496 /* minimum size of a block. */
120
121
122 struct stack_block {
123 struct stack_block *prev;
124 /* Data follows */
125 };
126 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
127
128 static struct stack_block *stackp;
129 char *stacknxt;
130 int stacknleft;
131 char *sstrend;
132
133
134 static void
stnewblock(int nbytes)135 stnewblock(int nbytes)
136 {
137 struct stack_block *sp;
138 int allocsize;
139
140 if (nbytes < MINSIZE)
141 nbytes = MINSIZE;
142
143 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
144
145 INTOFF;
146 sp = ckmalloc(allocsize);
147 sp->prev = stackp;
148 stacknxt = SPACE(sp);
149 stacknleft = allocsize - (stacknxt - (char*)sp);
150 sstrend = stacknxt + stacknleft;
151 stackp = sp;
152 INTON;
153 }
154
155
156 pointer
stalloc(int nbytes)157 stalloc(int nbytes)
158 {
159 char *p;
160
161 nbytes = ALIGN(nbytes);
162 if (nbytes > stacknleft)
163 stnewblock(nbytes);
164 p = stacknxt;
165 stacknxt += nbytes;
166 stacknleft -= nbytes;
167 return p;
168 }
169
170
171 void
stunalloc(pointer p)172 stunalloc(pointer p)
173 {
174 if (p == NULL) { /*DEBUG */
175 write(STDERR_FILENO, "stunalloc\n", 10);
176 abort();
177 }
178 stacknleft += stacknxt - (char *)p;
179 stacknxt = p;
180 }
181
182
183
184 void
setstackmark(struct stackmark * mark)185 setstackmark(struct stackmark *mark)
186 {
187 mark->stackp = stackp;
188 mark->stacknxt = stacknxt;
189 mark->stacknleft = stacknleft;
190 /* Ensure this block stays in place. */
191 if (stackp != NULL && stacknxt == SPACE(stackp))
192 stalloc(1);
193 }
194
195
196 void
popstackmark(struct stackmark * mark)197 popstackmark(struct stackmark *mark)
198 {
199 struct stack_block *sp;
200
201 INTOFF;
202 while (stackp != mark->stackp) {
203 sp = stackp;
204 stackp = sp->prev;
205 ckfree(sp);
206 }
207 stacknxt = mark->stacknxt;
208 stacknleft = mark->stacknleft;
209 sstrend = stacknxt + stacknleft;
210 INTON;
211 }
212
213
214 /*
215 * When the parser reads in a string, it wants to stick the string on the
216 * stack and only adjust the stack pointer when it knows how big the
217 * string is. Stackblock (defined in stack.h) returns a pointer to a block
218 * of space on top of the stack and stackblocklen returns the length of
219 * this block. Growstackblock will grow this space by at least one byte,
220 * possibly moving it (like realloc). Grabstackblock actually allocates the
221 * part of the block that has been used.
222 */
223
224 static void
growstackblock(int min)225 growstackblock(int min)
226 {
227 char *p;
228 int newlen;
229 char *oldspace;
230 int oldlen;
231 struct stack_block *sp;
232 struct stack_block *oldstackp;
233
234 if (min < stacknleft)
235 min = stacknleft;
236 if ((unsigned int)min >=
237 INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
238 error("Out of space");
239 min += stacknleft;
240 min += ALIGN(sizeof(struct stack_block));
241 newlen = 512;
242 while (newlen < min)
243 newlen <<= 1;
244 oldspace = stacknxt;
245 oldlen = stacknleft;
246
247 if (stackp != NULL && stacknxt == SPACE(stackp)) {
248 INTOFF;
249 oldstackp = stackp;
250 stackp = oldstackp->prev;
251 sp = ckrealloc((pointer)oldstackp, newlen);
252 sp->prev = stackp;
253 stackp = sp;
254 stacknxt = SPACE(sp);
255 stacknleft = newlen - (stacknxt - (char*)sp);
256 sstrend = stacknxt + stacknleft;
257 INTON;
258 } else {
259 newlen -= ALIGN(sizeof(struct stack_block));
260 p = stalloc(newlen);
261 if (oldlen != 0)
262 memcpy(p, oldspace, oldlen);
263 stunalloc(p);
264 }
265 }
266
267
268
269 /*
270 * The following routines are somewhat easier to use that the above.
271 * The user declares a variable of type STACKSTR, which may be declared
272 * to be a register. The macro STARTSTACKSTR initializes things. Then
273 * the user uses the macro STPUTC to add characters to the string. In
274 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
275 * grown as necessary. When the user is done, she can just leave the
276 * string there and refer to it using stackblock(). Or she can allocate
277 * the space for it using grabstackstr(). If it is necessary to allow
278 * someone else to use the stack temporarily and then continue to grow
279 * the string, the user should use grabstack to allocate the space, and
280 * then call ungrabstr(p) to return to the previous mode of operation.
281 *
282 * USTPUTC is like STPUTC except that it doesn't check for overflow.
283 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
284 * is space for at least one character.
285 */
286
287 static char *
growstrstackblock(int n,int min)288 growstrstackblock(int n, int min)
289 {
290 growstackblock(min);
291 return stackblock() + n;
292 }
293
294 char *
growstackstr(void)295 growstackstr(void)
296 {
297 int len;
298
299 len = stackblocksize();
300 return (growstrstackblock(len, 0));
301 }
302
303
304 /*
305 * Called from CHECKSTRSPACE.
306 */
307
308 char *
makestrspace(int min,char * p)309 makestrspace(int min, char *p)
310 {
311 int len;
312
313 len = p - stackblock();
314 return (growstrstackblock(len, min));
315 }
316
317
318 char *
stputbin(const char * data,size_t len,char * p)319 stputbin(const char *data, size_t len, char *p)
320 {
321 CHECKSTRSPACE(len, p);
322 memcpy(p, data, len);
323 return (p + len);
324 }
325
326 char *
stputs(const char * data,char * p)327 stputs(const char *data, char *p)
328 {
329 return (stputbin(data, strlen(data), p));
330 }
331