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37 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
43 #include <sys/param.h>
54 badalloc(const char *message)
56 write(2, message, strlen(message));
61 * Like malloc, but returns an error when out of space.
65 ckmalloc(size_t nbytes)
70 badalloc("Unsafe ckmalloc() call\n");
73 error("Out of space");
83 ckrealloc(pointer p, int nbytes)
86 badalloc("Unsafe ckrealloc() call\n");
87 p = realloc(p, nbytes);
89 error("Out of space");
97 badalloc("Unsafe ckfree() call\n");
103 * Make a copy of a string in safe storage.
107 savestr(const char *s)
113 p = ckmalloc(len + 1);
114 memcpy(p, s, len + 1);
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.
124 * The size 496 was chosen because with 16-byte alignment the total size
125 * for the allocated block is 512.
128 #define MINSIZE 496 /* minimum size of a block. */
132 struct stack_block *prev;
135 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
137 static struct stack_block *stackp;
144 stnewblock(int nbytes)
146 struct stack_block *sp;
149 if (nbytes < MINSIZE)
152 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
155 sp = ckmalloc(allocsize);
157 stacknxt = SPACE(sp);
158 stacknleft = allocsize - (stacknxt - (char*)sp);
159 sstrend = stacknxt + stacknleft;
170 nbytes = ALIGN(nbytes);
171 if (nbytes > stacknleft)
175 stacknleft -= nbytes;
183 if (p == NULL) { /*DEBUG */
184 write(STDERR_FILENO, "stunalloc\n", 10);
187 stacknleft += stacknxt - (char *)p;
193 stsavestr(const char *s)
199 p = stalloc(len + 1);
200 memcpy(p, s, len + 1);
206 setstackmark(struct stackmark *mark)
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))
218 popstackmark(struct stackmark *mark)
220 struct stack_block *sp;
223 while (stackp != mark->stackp) {
228 stacknxt = mark->stacknxt;
229 stacknleft = mark->stacknleft;
231 sstrend = stacknxt + stacknleft;
239 * When the parser reads in a string, it wants to stick the string on the
240 * stack and only adjust the stack pointer when it knows how big the
241 * string is. Stackblock (defined in stack.h) returns a pointer to a block
242 * of space on top of the stack and stackblocklen returns the length of
243 * this block. Growstackblock will grow this space by at least one byte,
244 * possibly moving it (like realloc). Grabstackblock actually allocates the
245 * part of the block that has been used.
249 growstackblock(int min)
255 struct stack_block *sp;
256 struct stack_block *oldstackp;
258 if (min < stacknleft)
260 if ((unsigned int)min >=
261 INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
262 error("Out of space");
264 min += ALIGN(sizeof(struct stack_block));
271 if (stackp != NULL && stacknxt == SPACE(stackp)) {
274 stackp = oldstackp->prev;
275 sp = ckrealloc((pointer)oldstackp, newlen);
278 stacknxt = SPACE(sp);
279 stacknleft = newlen - (stacknxt - (char*)sp);
280 sstrend = stacknxt + stacknleft;
283 newlen -= ALIGN(sizeof(struct stack_block));
286 memcpy(p, oldspace, oldlen);
294 * The following routines are somewhat easier to use that the above.
295 * The user declares a variable of type STACKSTR, which may be declared
296 * to be a register. The macro STARTSTACKSTR initializes things. Then
297 * the user uses the macro STPUTC to add characters to the string. In
298 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
299 * grown as necessary. When the user is done, she can just leave the
300 * string there and refer to it using stackblock(). Or she can allocate
301 * the space for it using grabstackstr(). If it is necessary to allow
302 * someone else to use the stack temporarily and then continue to grow
303 * the string, the user should use grabstack to allocate the space, and
304 * then call ungrabstr(p) to return to the previous mode of operation.
306 * USTPUTC is like STPUTC except that it doesn't check for overflow.
307 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
308 * is space for at least one character.
312 growstrstackblock(int n, int min)
315 return stackblock() + n;
323 len = stackblocksize();
324 return (growstrstackblock(len, 0));
329 * Called from CHECKSTRSPACE.
333 makestrspace(int min, char *p)
337 len = p - stackblock();
338 return (growstrstackblock(len, min));
343 stputbin(const char *data, size_t len, char *p)
345 CHECKSTRSPACE(len, p);
346 memcpy(p, data, len);
351 stputs(const char *data, char *p)
353 return (stputbin(data, strlen(data), p));