| /* ----------------------------------------------------------------------------- |
| * memory.c |
| * |
| * This file provides simple mmap() based memory management for WAD. Since |
| * the process heap-allocator might be corrupted when WAD is invoked, we |
| * have to do all of our own memory management. However, since WAD mostly |
| * just collects data, we only provide the function wad_malloc(). To |
| * release all allocated memory, the wad_release_memory() function should |
| * be used. |
| * |
| * Author(s) : David Beazley (beazley@cs.uchicago.edu) |
| * |
| * Copyright (C) 2000. The University of Chicago. |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| * See the file COPYING for a complete copy of the LGPL. |
| * ----------------------------------------------------------------------------- */ |
| |
| #include "wad.h" |
| |
| static char cvs[] = "$Header$"; |
| |
| typedef struct _WadMemory { |
| int npages; /* Number of pages */ |
| int last; /* Last offset in page */ |
| struct _WadMemory *next; /* Pointer to next allocation */ |
| } WadMemory; |
| |
| static WadMemory *current = 0; /* Current memory block */ |
| static int pagesize = 0; /* System page size */ |
| static int devzero = 0; |
| static int npalloc = 8; /* Number of pages per alloc */ |
| |
| /* ----------------------------------------------------------------------------- |
| * wad_memory_init() |
| * |
| * Initialize the WAD allocator. |
| * ----------------------------------------------------------------------------- */ |
| |
| int wad_memory_init() { |
| pagesize = getpagesize(); |
| devzero = open("/dev/zero", O_RDWR); |
| if (devzero < 0) { |
| wad_printf("WAD: couldn't open /dev/zero.\n"); |
| return -1; |
| } |
| return 0; |
| } |
| |
| /* ----------------------------------------------------------------------------- |
| * wad_page_alloc() |
| * |
| * Allocate pages using mmap |
| * ----------------------------------------------------------------------------- */ |
| |
| void *wad_page_alloc(int npages) { |
| void *m; |
| m = mmap(NULL, npages*pagesize, PROT_READ | PROT_WRITE, MAP_PRIVATE, devzero, 0); |
| if (((long) m) == -1) return 0; |
| /* printf("page_alloc: %x - %x\n", m, ((char *) m) + npages*pagesize); */ |
| return m; |
| } |
| |
| /* ----------------------------------------------------------------------------- |
| * wad_malloc() |
| * |
| * Allocate memory using mmap(). If the allocation is smaller than half a page, |
| * We'll look at current to see if there is enough space. If so, we'll just |
| * use that memory. Otherwise, we'll allocate a new page. If the allocation |
| * request is larger than a page, we'll round up to the nearest page size and |
| * do a special allocation. |
| * ----------------------------------------------------------------------------- */ |
| |
| void *wad_malloc(int nbytes) { |
| void *ptr; |
| WadMemory *wm; |
| char *c; |
| int npages; |
| /* wad_printf("wad_malloc: %d\n", nbytes); */ |
| if (nbytes >= ((npalloc*pagesize) >> 2)) { |
| /* Large allocation. */ |
| npages = ((nbytes + sizeof(WadMemory))/pagesize) + 1; |
| ptr = wad_page_alloc(npages); |
| if (!ptr) return 0; |
| wm = (WadMemory *)ptr; |
| wm->npages = npages; |
| wm->last = sizeof(WadMemory) + 8; |
| wm->next = current; |
| current = wm; |
| c = (char *) current + (current->last); |
| current->last += ((nbytes & ~0x7) + 8); |
| return c; |
| } |
| /* Small allocation. See if there are any regions big enough */ |
| wm = current; |
| while (wm) { |
| if (((wm->npages*pagesize) - wm->last) > nbytes) { |
| /* Yep. Found a region */ |
| break; |
| } |
| wm = wm->next; |
| } |
| if (!wm) { |
| /* wad_printf("wad_malloc: new page\n", nbytes);*/ |
| wm = (WadMemory *) wad_page_alloc(npalloc); |
| if (!wm) return 0; |
| wm->npages = npalloc; |
| wm->last = sizeof(WadMemory) + 8; |
| wm->next = current; |
| current = wm; |
| } |
| c = ((char *) wm) + (wm->last); |
| wm->last += ((nbytes & ~0x7) + 8); |
| return c; |
| } |
| |
| /* ----------------------------------------------------------------------------- |
| * wad_strdup() |
| * |
| * Duplicate a string |
| * ----------------------------------------------------------------------------- */ |
| |
| char *wad_strdup(const char *c) { |
| char *t; |
| if (!c) c = ""; |
| t = (char *) wad_malloc(strlen(c)+1); |
| wad_strcpy(t,c); |
| return t; |
| } |
| |
| /* ----------------------------------------------------------------------------- |
| * wad_memcpy() |
| * ----------------------------------------------------------------------------- */ |
| |
| void wad_memcpy(void *t, const void *s, unsigned len) { |
| char *tc, *sc; |
| int i; |
| tc = (char *) t; |
| sc = (char *) s; |
| for (i = 0; i < len; i++, tc++, sc++) |
| *tc = *sc; |
| } |
| |
| /* ----------------------------------------------------------------------------- |
| * wad_memory_debug() |
| * ----------------------------------------------------------------------------- */ |
| |
| void wad_memory_debug() { |
| int total_alloc = 0; |
| int inuse = 0; |
| WadMemory *m; |
| if (wad_debug_mode & DEBUG_MEMORY) { |
| m = current; |
| while (m) { |
| total_alloc += (m->npages)*pagesize; |
| inuse += m->last; |
| m = m->next; |
| } |
| wad_printf("WAD: memory allocated %d bytes (%d bytes used).\n", total_alloc, inuse); |
| } |
| } |