1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 #ifndef lint
36 #if 0
37 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
38 #endif
39 #endif /* not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD: head/bin/sh/memalloc.c 360452 2020-04-28 20:34:27Z jilles $");
42
43 #include <sys/param.h>
44 #include "shell.h"
45 #include "output.h"
46 #include "memalloc.h"
47 #include "error.h"
48 #include "mystring.h"
49 #include "expand.h"
50 #include <stdlib.h>
51 #include <unistd.h>
52
53 static void
badalloc(const char * message)54 badalloc(const char *message)
55 {
56 write(2, message, strlen(message));
57 abort();
58 }
59
60 /*
61 * Like malloc, but returns an error when out of space.
62 */
63
64 pointer
ckmalloc(size_t nbytes)65 ckmalloc(size_t nbytes)
66 {
67 pointer p;
68
69 if (!is_int_on())
70 badalloc("Unsafe ckmalloc() call\n");
71 p = malloc(nbytes);
72 if (p == NULL)
73 error("Out of space");
74 return p;
75 }
76
77
78 /*
79 * Same for realloc.
80 */
81
82 pointer
ckrealloc(pointer p,int nbytes)83 ckrealloc(pointer p, int nbytes)
84 {
85 if (!is_int_on())
86 badalloc("Unsafe ckrealloc() call\n");
87 p = realloc(p, nbytes);
88 if (p == NULL)
89 error("Out of space");
90 return p;
91 }
92
93 void
ckfree(pointer p)94 ckfree(pointer p)
95 {
96 if (!is_int_on())
97 badalloc("Unsafe ckfree() call\n");
98 free(p);
99 }
100
101
102 /*
103 * Make a copy of a string in safe storage.
104 */
105
106 char *
savestr(const char * s)107 savestr(const char *s)
108 {
109 char *p;
110 size_t len;
111
112 len = strlen(s);
113 p = ckmalloc(len + 1);
114 memcpy(p, s, len + 1);
115 return p;
116 }
117
118
119 /*
120 * Parse trees for commands are allocated in lifo order, so we use a stack
121 * to make this more efficient, and also to avoid all sorts of exception
122 * handling code to handle interrupts in the middle of a parse.
123 *
124 * The size 496 was chosen because with 16-byte alignment the total size
125 * for the allocated block is 512.
126 */
127
128 #define MINSIZE 496 /* minimum size of a block. */
129
130
131 struct stack_block {
132 struct stack_block *prev;
133 /* Data follows */
134 };
135 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
136
137 static struct stack_block *stackp;
138 char *stacknxt;
139 int stacknleft;
140 char *sstrend;
141
142
143 static void
stnewblock(int nbytes)144 stnewblock(int nbytes)
145 {
146 struct stack_block *sp;
147 int allocsize;
148
149 if (nbytes < MINSIZE)
150 nbytes = MINSIZE;
151
152 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
153
154 INTOFF;
155 sp = ckmalloc(allocsize);
156 sp->prev = stackp;
157 stacknxt = SPACE(sp);
158 stacknleft = allocsize - (stacknxt - (char*)sp);
159 sstrend = stacknxt + stacknleft;
160 stackp = sp;
161 INTON;
162 }
163
164
165 pointer
stalloc(int nbytes)166 stalloc(int nbytes)
167 {
168 char *p;
169
170 nbytes = ALIGN(nbytes);
171 if (nbytes > stacknleft)
172 stnewblock(nbytes);
173 p = stacknxt;
174 stacknxt += nbytes;
175 stacknleft -= nbytes;
176 return p;
177 }
178
179
180 void
stunalloc(pointer p)181 stunalloc(pointer p)
182 {
183 if (p == NULL) { /*DEBUG */
184 write(STDERR_FILENO, "stunalloc\n", 10);
185 abort();
186 }
187 stacknleft += stacknxt - (char *)p;
188 stacknxt = p;
189 }
190
191
192 char *
stsavestr(const char * s)193 stsavestr(const char *s)
194 {
195 char *p;
196 size_t len;
197
198 len = strlen(s);
199 p = stalloc(len + 1);
200 memcpy(p, s, len + 1);
201 return p;
202 }
203
204
205 void
setstackmark(struct stackmark * mark)206 setstackmark(struct stackmark *mark)
207 {
208 mark->stackp = stackp;
209 mark->stacknxt = stacknxt;
210 mark->stacknleft = stacknleft;
211 /* Ensure this block stays in place. */
212 if (stackp != NULL && stacknxt == SPACE(stackp))
213 stalloc(1);
214 }
215
216
217 void
popstackmark(struct stackmark * mark)218 popstackmark(struct stackmark *mark)
219 {
220 struct stack_block *sp;
221
222 INTOFF;
223 while (stackp != mark->stackp) {
224 sp = stackp;
225 stackp = sp->prev;
226 ckfree(sp);
227 }
228 stacknxt = mark->stacknxt;
229 stacknleft = mark->stacknleft;
230 sstrend = stacknxt + stacknleft;
231 INTON;
232 }
233
234
235 /*
236 * When the parser reads in a string, it wants to stick the string on the
237 * stack and only adjust the stack pointer when it knows how big the
238 * string is. Stackblock (defined in stack.h) returns a pointer to a block
239 * of space on top of the stack and stackblocklen returns the length of
240 * this block. Growstackblock will grow this space by at least one byte,
241 * possibly moving it (like realloc). Grabstackblock actually allocates the
242 * part of the block that has been used.
243 */
244
245 static void
growstackblock(int min)246 growstackblock(int min)
247 {
248 char *p;
249 int newlen;
250 char *oldspace;
251 int oldlen;
252 struct stack_block *sp;
253 struct stack_block *oldstackp;
254
255 if (min < stacknleft)
256 min = stacknleft;
257 if ((unsigned int)min >=
258 INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
259 error("Out of space");
260 min += stacknleft;
261 min += ALIGN(sizeof(struct stack_block));
262 newlen = 512;
263 while (newlen < min)
264 newlen <<= 1;
265 oldspace = stacknxt;
266 oldlen = stacknleft;
267
268 if (stackp != NULL && stacknxt == SPACE(stackp)) {
269 INTOFF;
270 oldstackp = stackp;
271 stackp = oldstackp->prev;
272 sp = ckrealloc((pointer)oldstackp, newlen);
273 sp->prev = stackp;
274 stackp = sp;
275 stacknxt = SPACE(sp);
276 stacknleft = newlen - (stacknxt - (char*)sp);
277 sstrend = stacknxt + stacknleft;
278 INTON;
279 } else {
280 newlen -= ALIGN(sizeof(struct stack_block));
281 p = stalloc(newlen);
282 if (oldlen != 0)
283 memcpy(p, oldspace, oldlen);
284 stunalloc(p);
285 }
286 }
287
288
289
290 /*
291 * The following routines are somewhat easier to use that the above.
292 * The user declares a variable of type STACKSTR, which may be declared
293 * to be a register. The macro STARTSTACKSTR initializes things. Then
294 * the user uses the macro STPUTC to add characters to the string. In
295 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
296 * grown as necessary. When the user is done, she can just leave the
297 * string there and refer to it using stackblock(). Or she can allocate
298 * the space for it using grabstackstr(). If it is necessary to allow
299 * someone else to use the stack temporarily and then continue to grow
300 * the string, the user should use grabstack to allocate the space, and
301 * then call ungrabstr(p) to return to the previous mode of operation.
302 *
303 * USTPUTC is like STPUTC except that it doesn't check for overflow.
304 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
305 * is space for at least one character.
306 */
307
308 static char *
growstrstackblock(int n,int min)309 growstrstackblock(int n, int min)
310 {
311 growstackblock(min);
312 return stackblock() + n;
313 }
314
315 char *
growstackstr(void)316 growstackstr(void)
317 {
318 int len;
319
320 len = stackblocksize();
321 return (growstrstackblock(len, 0));
322 }
323
324
325 /*
326 * Called from CHECKSTRSPACE.
327 */
328
329 char *
makestrspace(int min,char * p)330 makestrspace(int min, char *p)
331 {
332 int len;
333
334 len = p - stackblock();
335 return (growstrstackblock(len, min));
336 }
337
338
339 char *
stputbin(const char * data,size_t len,char * p)340 stputbin(const char *data, size_t len, char *p)
341 {
342 CHECKSTRSPACE(len, p);
343 memcpy(p, data, len);
344 return (p + len);
345 }
346
347 char *
stputs(const char * data,char * p)348 stputs(const char *data, char *p)
349 {
350 return (stputbin(data, strlen(data), p));
351 }
352