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