1 /*-
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 * Copyright (c) 1997-2005
5 * Herbert Xu <herbert@gondor.apana.org.au>. 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 <stdlib.h>
36 #include <unistd.h>
37
38 #include "shell.h"
39 #include "output.h"
40 #include "memalloc.h"
41 #include "error.h"
42 #include "machdep.h"
43 #include "mystring.h"
44 #include "system.h"
45
46 /*
47 * Like malloc, but returns an error when out of space.
48 */
49
50 pointer
ckmalloc(size_t nbytes)51 ckmalloc(size_t nbytes)
52 {
53 pointer p;
54
55 p = malloc(nbytes);
56 if (p == NULL)
57 sh_error("Out of space");
58 return p;
59 }
60
61
62 /*
63 * Same for realloc.
64 */
65
66 pointer
ckrealloc(pointer p,size_t nbytes)67 ckrealloc(pointer p, size_t nbytes)
68 {
69 p = realloc(p, nbytes);
70 if (p == NULL)
71 sh_error("Out of space");
72 return p;
73 }
74
75
76 /*
77 * Make a copy of a string in safe storage.
78 */
79
80 char *
savestr(const char * s)81 savestr(const char *s)
82 {
83 char *p = strdup(s);
84 if (!p)
85 sh_error("Out of space");
86 return p;
87 }
88
89
90 /*
91 * Parse trees for commands are allocated in lifo order, so we use a stack
92 * to make this more efficient, and also to avoid all sorts of exception
93 * handling code to handle interrupts in the middle of a parse.
94 *
95 * The size 504 was chosen because the Ultrix malloc handles that size
96 * well.
97 */
98
99 /* minimum size of a block */
100 #define MINSIZE SHELL_ALIGN(504)
101
102 struct stack_block {
103 struct stack_block *prev;
104 char space[MINSIZE];
105 };
106
107 struct stack_block stackbase;
108 struct stack_block *stackp = &stackbase;
109 char *stacknxt = stackbase.space;
110 size_t stacknleft = MINSIZE;
111 char *sstrend = stackbase.space + MINSIZE;
112
113 pointer
stalloc(size_t nbytes)114 stalloc(size_t nbytes)
115 {
116 char *p;
117 size_t aligned;
118
119 aligned = SHELL_ALIGN(nbytes);
120 if (aligned > stacknleft) {
121 size_t len;
122 size_t blocksize;
123 struct stack_block *sp;
124
125 blocksize = aligned;
126 if (blocksize < MINSIZE)
127 blocksize = MINSIZE;
128 len = sizeof(struct stack_block) - MINSIZE + blocksize;
129 if (len < blocksize)
130 sh_error("Out of space");
131 INTOFF;
132 sp = ckmalloc(len);
133 sp->prev = stackp;
134 stacknxt = sp->space;
135 stacknleft = blocksize;
136 sstrend = stacknxt + blocksize;
137 stackp = sp;
138 INTON;
139 }
140 p = stacknxt;
141 stacknxt += aligned;
142 stacknleft -= aligned;
143 return p;
144 }
145
146
147 void
stunalloc(pointer p)148 stunalloc(pointer p)
149 {
150 #ifdef DEBUG
151 if (!p || (stacknxt < (char *)p) || ((char *)p < stackp->space)) {
152 write(2, "stunalloc\n", 10);
153 abort();
154 }
155 #endif
156 stacknleft += stacknxt - (char *)p;
157 stacknxt = p;
158 }
159
160
161
pushstackmark(struct stackmark * mark,size_t len)162 void pushstackmark(struct stackmark *mark, size_t len)
163 {
164 mark->stackp = stackp;
165 mark->stacknxt = stacknxt;
166 mark->stacknleft = stacknleft;
167 grabstackblock(len);
168 }
169
setstackmark(struct stackmark * mark)170 void setstackmark(struct stackmark *mark)
171 {
172 pushstackmark(mark, stacknxt == stackp->space && stackp != &stackbase);
173 }
174
175
176 void
popstackmark(struct stackmark * mark)177 popstackmark(struct stackmark *mark)
178 {
179 struct stack_block *sp;
180
181 INTOFF;
182 while (stackp != mark->stackp) {
183 sp = stackp;
184 stackp = sp->prev;
185 ckfree(sp);
186 }
187 stacknxt = mark->stacknxt;
188 stacknleft = mark->stacknleft;
189 sstrend = mark->stacknxt + mark->stacknleft;
190 INTON;
191 }
192
193
194 /*
195 * When the parser reads in a string, it wants to stick the string on the
196 * stack and only adjust the stack pointer when it knows how big the
197 * string is. Stackblock (defined in stack.h) returns a pointer to a block
198 * of space on top of the stack and stackblocklen returns the length of
199 * this block. Growstackblock will grow this space by at least one byte,
200 * possibly moving it (like realloc). Grabstackblock actually allocates the
201 * part of the block that has been used.
202 */
203
growstackblock(size_t min)204 static void growstackblock(size_t min)
205 {
206 size_t newlen;
207
208 newlen = stacknleft * 2;
209 if (newlen < stacknleft)
210 sh_error("Out of space");
211 min = SHELL_ALIGN(min | 128);
212 if (newlen < min)
213 newlen += min;
214
215 if (stacknxt == stackp->space && stackp != &stackbase) {
216 struct stack_block *sp;
217 struct stack_block *prevstackp;
218 size_t grosslen;
219
220 INTOFF;
221 sp = stackp;
222 prevstackp = sp->prev;
223 grosslen = newlen + sizeof(struct stack_block) - MINSIZE;
224 sp = ckrealloc((pointer)sp, grosslen);
225 sp->prev = prevstackp;
226 stackp = sp;
227 stacknxt = sp->space;
228 stacknleft = newlen;
229 sstrend = sp->space + newlen;
230 INTON;
231 } else {
232 char *oldspace = stacknxt;
233 int oldlen = stacknleft;
234 char *p = stalloc(newlen);
235
236 /* free the space we just allocated */
237 stacknxt = memcpy(p, oldspace, oldlen);
238 stacknleft += newlen;
239 }
240 }
241
242 /*
243 * The following routines are somewhat easier to use than the above.
244 * The user declares a variable of type STACKSTR, which may be declared
245 * to be a register. The macro STARTSTACKSTR initializes things. Then
246 * the user uses the macro STPUTC to add characters to the string. In
247 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
248 * grown as necessary. When the user is done, she can just leave the
249 * string there and refer to it using stackblock(). Or she can allocate
250 * the space for it using grabstackstr(). If it is necessary to allow
251 * someone else to use the stack temporarily and then continue to grow
252 * the string, the user should use grabstack to allocate the space, and
253 * then call ungrabstr(p) to return to the previous mode of operation.
254 *
255 * USTPUTC is like STPUTC except that it doesn't check for overflow.
256 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
257 * is space for at least one character.
258 */
259
260 void *
growstackstr(void)261 growstackstr(void)
262 {
263 size_t len = stackblocksize();
264
265 growstackblock(0);
266 return stackblock() + len;
267 }
268
growstackto(size_t len)269 char *growstackto(size_t len)
270 {
271 if (stackblocksize() < len)
272 growstackblock(len);
273 return stackblock();
274 }
275
276 /*
277 * Called from CHECKSTRSPACE.
278 */
279
280 char *
makestrspace(size_t newlen,char * p)281 makestrspace(size_t newlen, char *p)
282 {
283 size_t len = p - stacknxt;
284
285 return growstackto(len + newlen) + len;
286 }
287
288 char *
stnputs(const char * s,size_t n,char * p)289 stnputs(const char *s, size_t n, char *p)
290 {
291 p = makestrspace(n, p);
292 p = mempcpy(p, s, n);
293 return p;
294 }
295
296 char *
stputs(const char * s,char * p)297 stputs(const char *s, char *p)
298 {
299 return stnputs(s, strlen(s), p);
300 }
301