1 /* Initialization for acces s to a mmap'd malloc managed region. */
3 /* Copyright (c) 2012-2014. The SimGrid Team.
4 * All rights reserved. */
6 /* This program is free software; you can redistribute it and/or modify it
7 * under the terms of the license (GNU LGPL) which comes with this package. */
9 /* Copyright 1992, 2000 Free Software Foundation, Inc.
11 Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com
13 This file is part of the GNU C Library.
15 The GNU C Library is free software; you can redistribute it and/or
16 modify it under the terms of the GNU Library General Public License as
17 published by the Free Software Foundation; either version 2 of the
18 License, or (at your option) any later version.
20 The GNU C Library is distributed in the hope that it will be useful,
21 but WITHOUT ANY WARRANTY; without even the implied warranty of
22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 Library General Public License for more details.
25 You should have received a copy of the GNU Library General Public
26 License along with the GNU C Library; see the file COPYING.LIB. If
27 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
28 Boston, MA 02111-1307, USA. */
30 #include <sys/types.h>
31 #include <fcntl.h> /* After sys/types.h, at least for dpx/2. */
35 #include <unistd.h> /* Prototypes for lseek */
37 #include "mmprivate.h"
39 #include "xbt_modinter.h" /* declarations of mmalloc_preinit and friends that live here */
45 /* Initialize access to a mmalloc managed region.
47 If FD is a valid file descriptor for an open file then data for the
48 mmalloc managed region is mapped to that file, otherwise an anonymous
49 map is used if supported by the underlying OS. In case of running in
50 an OS without support of anonymous mappings then "/dev/zero" is used
51 and in both cases the data will not exist in any filesystem object.
53 If the open file corresponding to FD is from a previous use of
54 mmalloc and passes some basic sanity checks to ensure that it is
55 compatible with the current mmalloc package, then its data is
56 mapped in and is immediately accessible at the same addresses in
57 the current process as the process that created the file (ignoring
58 the BASEADDR parameter).
60 For non valid FDs or empty files ones the mapping is established
61 starting at the specified address BASEADDR in the process address
64 The provided BASEADDR should be choosed carefully in order to avoid
65 bumping into existing mapped regions or future mapped regions.
67 On success, returns a "malloc descriptor" which is used in subsequent
68 calls to other mmalloc package functions. It is explicitly "void *"
69 so that users of the package don't have to worry about the actual
70 implementation details.
72 On failure returns NULL. */
74 xbt_mheap_t xbt_mheap_new(int fd, void *baseaddr)
76 return xbt_mheap_new_options(fd, baseaddr, 0);
79 xbt_mheap_t xbt_mheap_new_options(int fd, void *baseaddr, int options)
86 /* First check to see if FD is a valid file descriptor, and if so, see
87 if the file has any current contents (size > 0). If it does, then
88 attempt to reuse the file. If we can't reuse the file, either
89 because it isn't a valid mmalloc produced file, was produced by an
90 obsolete version, or any other reason, then we fail to attach to
94 if (fstat(fd, &sbuf) < 0)
97 else if (sbuf.st_size > 0) {
98 /* We were given an valid file descriptor on an open file, so try to remap
99 it into the current process at the same address to which it was previously
100 mapped. It naturally have to pass some sanity checks for that.
102 Note that we have to update the file descriptor number in the malloc-
103 descriptor read from the file to match the current valid one, before
104 trying to map the file in, and again after a successful mapping and
105 after we've switched over to using the mapped in malloc descriptor
106 rather than the temporary one on the stack.
108 Once we've switched over to using the mapped in malloc descriptor, we
109 have to update the pointer to the morecore function, since it almost
110 certainly will be at a different address if the process reusing the
111 mapped region is from a different executable.
113 Also note that if the heap being remapped previously used the mmcheckf()
114 routines, we need to update the hooks since their target functions
115 will have certainly moved if the executable has changed in any way.
116 We do this by calling mmcheckf() internally.
118 Returns a pointer to the malloc descriptor if successful, or NULL if
119 unsuccessful for some reason. */
122 struct mdesc *mdptr = NULL, *mdptemp = NULL;
124 if (lseek(fd, 0L, SEEK_SET) != 0)
126 if (read(fd, (char *) &newmd, sizeof(newmd)) != sizeof(newmd))
128 if (newmd.headersize != sizeof(newmd))
130 if (strcmp(newmd.magic, MMALLOC_MAGIC) != 0)
132 if (newmd.version > MMALLOC_VERSION)
136 if (__mmalloc_remap_core(&newmd) == newmd.base) {
137 mdptr = (struct mdesc *) newmd.base;
139 if(!mdptr->refcount){
140 pthread_mutex_init(&mdptr->mutex, NULL);
145 /* Add the new heap to the linked list of heaps attached by mmalloc */
146 mdptemp = __mmalloc_default_mdp;
147 while(mdptemp->next_mdesc)
148 mdptemp = mdptemp->next_mdesc;
151 mdptemp->next_mdesc = mdptr;
158 /* NULL is not a valid baseaddr as we cannot map anything there.
159 C'mon, user. Think! */
160 if (baseaddr == NULL)
163 /* We start off with the malloc descriptor allocated on the stack, until
164 we build it up enough to call _mmalloc_mmap_morecore() to allocate the
165 first page of the region and copy it there. Ensure that it is zero'd and
166 then initialize the fields that we know values for. */
169 memset((char *) mdp, 0, sizeof(mtemp));
170 strncpy(mdp->magic, MMALLOC_MAGIC, MMALLOC_MAGIC_SIZE);
171 mdp->headersize = sizeof(mtemp);
172 mdp->version = MMALLOC_VERSION;
174 mdp->base = mdp->breakval = mdp->top = baseaddr;
175 mdp->next_mdesc = NULL;
177 mdp->options = options;
179 /* If we have not been passed a valid open file descriptor for the file
180 to map to, then we go for an anonymous map */
183 mdp->flags |= MMALLOC_ANONYMOUS;
185 pthread_mutex_init(&mdp->mutex, NULL);
186 /* If we have not been passed a valid open file descriptor for the file
187 to map to, then open /dev/zero and use that to map to. */
189 /* Now try to map in the first page, copy the malloc descriptor structure
190 there, and arrange to return a pointer to this new copy. If the mapping
191 fails, then close the file descriptor if it was opened by us, and arrange
194 if ((mbase = mmorecore(mdp, sizeof(mtemp))) != NULL) {
195 memcpy(mbase, mdp, sizeof(mtemp));
197 fprintf(stderr, "morecore failed to get some more memory!\n");
201 /* Add the new heap to the linked list of heaps attached by mmalloc */
202 if(__mmalloc_default_mdp){
203 mdp = __mmalloc_default_mdp;
204 while(mdp->next_mdesc)
205 mdp = mdp->next_mdesc;
208 mdp->next_mdesc = (struct mdesc *)mbase;
217 /** Terminate access to a mmalloc managed region, but do not free its content.
219 * This is for example useful for the base region where ldl stores its data
220 * because it leaves the place after us.
222 void xbt_mheap_destroy_no_free(xbt_mheap_t md)
224 struct mdesc *mdp = md;
226 if(--mdp->refcount == 0){
227 pthread_mutex_destroy(&mdp->mutex);
231 /** Terminate access to a mmalloc managed region by unmapping all memory pages
232 associated with the region, and closing the file descriptor if it is one
235 Returns NULL on success.
237 Returns the malloc descriptor on failure, which can subsequently be used
238 for further action, such as obtaining more information about the nature of
241 Note that the malloc descriptor that we are using is currently located in
242 region we are about to unmap, so we first make a local copy of it on the
243 stack and use the copy. */
245 void *xbt_mheap_destroy(xbt_mheap_t mdp)
247 struct mdesc mtemp, *mdptemp;
250 /* Remove the heap from the linked list of heaps attached by mmalloc */
251 mdptemp = __mmalloc_default_mdp;
252 while(mdptemp->next_mdesc != mdp )
253 mdptemp = mdptemp->next_mdesc;
255 mdptemp->next_mdesc = mdp->next_mdesc;
257 xbt_mheap_destroy_no_free(mdp);
260 /* Now unmap all the pages associated with this region by asking for a
261 negative increment equal to the current size of the region. */
263 if (mmorecore(&mtemp, (char *)mtemp.base - (char *)mtemp.breakval) == NULL) {
264 /* Deallocating failed. Update the original malloc descriptor
268 if (mtemp.flags & MMALLOC_DEVZERO) {
278 /* Safety gap from the heap's break address.
279 * Try to increase this first if you experience strange errors under
281 #define HEAP_OFFSET (128UL<<20)
283 xbt_mheap_t mmalloc_get_default_md(void)
285 xbt_assert(__mmalloc_default_mdp);
286 return __mmalloc_default_mdp;
289 static void mmalloc_fork_prepare(void)
291 xbt_mheap_t mdp = NULL;
292 if ((mdp =__mmalloc_default_mdp)){
298 mdp = mdp->next_mdesc;
303 static void mmalloc_fork_parent(void)
305 xbt_mheap_t mdp = NULL;
306 if ((mdp =__mmalloc_default_mdp)){
310 mdp = mdp->next_mdesc;
315 static void mmalloc_fork_child(void)
317 struct mdesc* mdp = NULL;
318 if ((mdp =__mmalloc_default_mdp)){
321 mdp = mdp->next_mdesc;
326 /* Initialize the default malloc descriptor. */
327 void *mmalloc_preinit(void)
330 if (__mmalloc_default_mdp == NULL) {
332 xbt_pagesize = getpagesize();
333 unsigned long mask = ~((unsigned long)xbt_pagesize - 1);
334 void *addr = (void*)(((unsigned long)sbrk(0) + HEAP_OFFSET) & mask);
335 __mmalloc_default_mdp = xbt_mheap_new_options(-1, addr, XBT_MHEAP_OPTION_MEMSET);
336 /* Fixme? only the default mdp in protected against forks */
337 // This is mandated to protect the mmalloced areas through forks. Think of tesh.
338 // Nah, removing the mutex isn't a good idea either for tesh
339 res = xbt_os_thread_atfork(mmalloc_fork_prepare,
340 mmalloc_fork_parent, mmalloc_fork_child);
342 THROWF(system_error,0,"xbt_os_thread_atfork() failed: return value %d",res);
344 xbt_assert(__mmalloc_default_mdp != NULL);
346 return __mmalloc_default_mdp;
349 void mmalloc_postexit(void)
351 /* Do not destroy the default mdp or ldl won't be able to free the memory it
352 * allocated since we're in memory */
353 // xbt_mheap_destroy_no_free(__mmalloc_default_mdp);
356 // This is the underlying implementation of mmalloc_get_bytes_used_remote.
357 // Is it used directly in order to evaluate the bytes used from a different
359 size_t mmalloc_get_bytes_used_remote(size_t heaplimit, const malloc_info* heapinfo)
362 for (size_t i=0; i < heaplimit; ++i){
363 if (heapinfo[i].type == MMALLOC_TYPE_UNFRAGMENTED){
364 if (heapinfo[i].busy_block.busy_size > 0)
365 bytes += heapinfo[i].busy_block.busy_size;
366 } else if (heapinfo[i].type > 0) {
367 for (size_t j=0; j < (size_t) (BLOCKSIZE >> heapinfo[i].type); j++){
368 if(heapinfo[i].busy_frag.frag_size[j] > 0)
369 bytes += heapinfo[i].busy_frag.frag_size[j];
376 size_t mmalloc_get_bytes_used(const xbt_mheap_t heap){
377 const struct mdesc* heap_data = (const struct mdesc *) heap;
378 return mmalloc_get_bytes_used_remote(heap_data->heaplimit, heap_data->heapinfo);
381 ssize_t mmalloc_get_busy_size(xbt_mheap_t heap, void *ptr){
383 ssize_t block = ((char*)ptr - (char*)(heap->heapbase)) / BLOCKSIZE + 1;
384 if(heap->heapinfo[block].type < 0)
386 else if(heap->heapinfo[block].type == MMALLOC_TYPE_UNFRAGMENTED)
387 return heap->heapinfo[block].busy_block.busy_size;
389 ssize_t frag = ((uintptr_t) (ADDR2UINT (ptr) % (BLOCKSIZE))) >> heap->heapinfo[block].type;
390 return heap->heapinfo[block].busy_frag.frag_size[frag];
395 void mmcheck(xbt_mheap_t heap) {return;
398 malloc_info* heapinfo = NULL;
399 for (size_t i=1; i < heap->heaplimit; i += mmalloc_get_increment(heapinfo)) {
400 heapinfo = heap->heapinfo + i;
401 switch (heapinfo->type) {
402 case MMALLOC_TYPE_HEAPINFO:
403 case MMALLOC_TYPE_FREE:
404 if (heapinfo->free_block.size==0) {
405 xbt_die("Block size == 0");
408 case MMALLOC_TYPE_UNFRAGMENTED:
409 if (heapinfo->busy_block.size==0) {
410 xbt_die("Block size == 0");
412 if (heapinfo->busy_block.busy_size==0 && heapinfo->busy_block.size!=0) {
413 xbt_die("Empty busy block");
417 if (heapinfo->type<0) {
418 xbt_die("Unkown mmalloc block type.");