src/ash/memalloc.c

   1 /*      $NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc Exp $        */
   2
   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 #ifdef HAVE_SYS_CDEFS_H
  36 #include <sys/cdefs.h>
  37 #endif
  38 #ifndef lint
  39 #if 0
  40 static char sccsid[] = "@(#)memalloc.c  8.3 (Berkeley) 5/4/95";
  41 #else
  42 __RCSID("$NetBSD: memalloc.c,v 1.28 2003/08/07 09:05:34 agc Exp $");
  43 #endif
  44 #endif /* not lint */
  45
  46 #include <stdlib.h>
  47 #include <unistd.h>
  48
  49 #include "shell.h"
  50 #include "output.h"
  51 #include "memalloc.h"
  52 #include "error.h"
  53 #include "machdep.h"
  54 #include "mystring.h"
  55
  56 /*
  57  * Like malloc, but returns an error when out of space.
  58  */
  59
  60 pointer
  61 ckmalloc(int nbytes)
  62 {
  63         pointer p;
  64
  65         p = malloc(nbytes);
  66         if (p == NULL)
  67                 error("Out of space");
  68         return p;
  69 }
  70
  71
  72 /*
  73  * Same for realloc.
  74  */
  75
  76 pointer
  77 ckrealloc(pointer p, int nbytes)
  78 {
  79         p = realloc(p, nbytes);
  80         if (p == NULL)
  81                 error("Out of space");
  82         return p;
  83 }
  84
  85
  86 /*
  87  * Make a copy of a string in safe storage.
  88  */
  89
  90 char *
  91 savestr(const char *s)
  92 {
  93         char *p;
  94
  95         p = ckmalloc(strlen(s) + 1);
  96         scopy(s, p);
  97         return p;
  98 }
  99
 100
 101 /*
 102  * Parse trees for commands are allocated in lifo order, so we use a stack
 103  * to make this more efficient, and also to avoid all sorts of exception
 104  * handling code to handle interrupts in the middle of a parse.
 105  *
 106  * The size 504 was chosen because the Ultrix malloc handles that size
 107  * well.
 108  */
 109
 110 #define MINSIZE 504             /* minimum size of a block */
 111
 112 struct stack_block {
 113         struct stack_block *prev;
 114         char space[MINSIZE];
 115 };
 116
 117 struct stack_block stackbase;
 118 struct stack_block *stackp = &stackbase;
 119 struct stackmark *markp;
 120 char *stacknxt = stackbase.space;
 121 int stacknleft = MINSIZE;
 122 int sstrnleft;
 123 int herefd = -1;
 124
 125 pointer
 126 stalloc(int nbytes)
 127 {
 128         char *p;
 129
 130         nbytes = SHELL_ALIGN(nbytes);
 131         if (nbytes > stacknleft) {
 132                 int blocksize;
 133                 struct stack_block *sp;
 134
 135                 blocksize = nbytes;
 136                 if (blocksize < MINSIZE)
 137                         blocksize = MINSIZE;
 138                 INTOFF;
 139                 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize);
 140                 sp->prev = stackp;
 141                 stacknxt = sp->space;
 142                 stacknleft = blocksize;
 143                 stackp = sp;
 144                 INTON;
 145         }
 146         p = stacknxt;
 147         stacknxt += nbytes;
 148         stacknleft -= nbytes;
 149         return p;
 150 }
 151
 152
 153 void
 154 stunalloc(pointer p)
 155 {
 156         if (p == NULL) {                /*DEBUG */
 157                 write(2, "stunalloc\n", 10);
 158                 abort();
 159         }
 160         stacknleft += stacknxt - (char *)p;
 161         stacknxt = p;
 162 }
 163
 164
 165
 166 void
 167 setstackmark(struct stackmark *mark)
 168 {
 169         mark->stackp = stackp;
 170         mark->stacknxt = stacknxt;
 171         mark->stacknleft = stacknleft;
 172         mark->marknext = markp;
 173         markp = mark;
 174 }
 175
 176
 177 void
 178 popstackmark(struct stackmark *mark)
 179 {
 180         struct stack_block *sp;
 181
 182         INTOFF;
 183         markp = mark->marknext;
 184         while (stackp != mark->stackp) {
 185                 sp = stackp;
 186                 stackp = sp->prev;
 187                 ckfree(sp);
 188         }
 189         stacknxt = mark->stacknxt;
 190         stacknleft = mark->stacknleft;
 191         INTON;
 192 }
 193
 194
 195 /*
 196  * When the parser reads in a string, it wants to stick the string on the
 197  * stack and only adjust the stack pointer when it knows how big the
 198  * string is.  Stackblock (defined in stack.h) returns a pointer to a block
 199  * of space on top of the stack and stackblocklen returns the length of
 200  * this block.  Growstackblock will grow this space by at least one byte,
 201  * possibly moving it (like realloc).  Grabstackblock actually allocates the
 202  * part of the block that has been used.
 203  */
 204
 205 void
 206 growstackblock(void)
 207 {
 208         int newlen = SHELL_ALIGN(stacknleft * 2 + 100);
 209
 210         if (stacknxt == stackp->space && stackp != &stackbase) {
 211                 struct stack_block *oldstackp;
 212                 struct stackmark *xmark;
 213                 struct stack_block *sp;
 214
 215                 INTOFF;
 216                 oldstackp = stackp;
 217                 sp = stackp;
 218                 stackp = sp->prev;
 219                 sp = ckrealloc((pointer)sp,
 220                     sizeof(struct stack_block) - MINSIZE + newlen);
 221                 sp->prev = stackp;
 222                 stackp = sp;
 223                 stacknxt = sp->space;
 224                 stacknleft = newlen;
 225
 226                 /*
 227                  * Stack marks pointing to the start of the old block
 228                  * must be relocated to point to the new block
 229                  */
 230                 xmark = markp;
 231                 while (xmark != NULL && xmark->stackp == oldstackp) {
 232                         xmark->stackp = stackp;
 233                         xmark->stacknxt = stacknxt;
 234                         xmark->stacknleft = stacknleft;
 235                         xmark = xmark->marknext;
 236                 }
 237                 INTON;
 238         } else {
 239                 char *oldspace = stacknxt;
 240                 int oldlen = stacknleft;
 241                 char *p = stalloc(newlen);
 242
 243                 (void)memcpy(p, oldspace, oldlen);
 244                 stacknxt = p;                   /* free the space */
 245                 stacknleft += newlen;           /* we just allocated */
 246         }
 247 }
 248
 249 void
 250 grabstackblock(int len)
 251 {
 252         len = SHELL_ALIGN(len);
 253         stacknxt += len;
 254         stacknleft -= len;
 255 }
 256
 257 /*
 258  * The following routines are somewhat easier to use than the above.
 259  * The user declares a variable of type STACKSTR, which may be declared
 260  * to be a register.  The macro STARTSTACKSTR initializes things.  Then
 261  * the user uses the macro STPUTC to add characters to the string.  In
 262  * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
 263  * grown as necessary.  When the user is done, she can just leave the
 264  * string there and refer to it using stackblock().  Or she can allocate
 265  * the space for it using grabstackstr().  If it is necessary to allow
 266  * someone else to use the stack temporarily and then continue to grow
 267  * the string, the user should use grabstack to allocate the space, and
 268  * then call ungrabstr(p) to return to the previous mode of operation.
 269  *
 270  * USTPUTC is like STPUTC except that it doesn't check for overflow.
 271  * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
 272  * is space for at least one character.
 273  */
 274
 275 char *
 276 growstackstr(void)
 277 {
 278         int len = stackblocksize();
 279         if (herefd >= 0 && len >= 1024) {
 280                 xwrite(herefd, stackblock(), len);
 281                 sstrnleft = len - 1;
 282                 return stackblock();
 283         }
 284         growstackblock();
 285         sstrnleft = stackblocksize() - len - 1;
 286         return stackblock() + len;
 287 }
 288
 289 /*
 290  * Called from CHECKSTRSPACE.
 291  */
 292
 293 char *
 294 makestrspace(void)
 295 {
 296         int len = stackblocksize() - sstrnleft;
 297         growstackblock();
 298         sstrnleft = stackblocksize() - len;
 299         return stackblock() + len;
 300 }
 301
 302 void
 303 ungrabstackstr(char *s, char *p)
 304 {
 305         stacknleft += stacknxt - s;
 306         stacknxt = s;
 307         sstrnleft = stacknleft - (p - s);
 308
 309 }