1 /* Initialization for access 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 sem_init(&mdptr->sem, 0, 1);
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 sem_init(&mdp->sem, 0, 1);
187 /* If we have not been passed a valid open file descriptor for the file
188 to map to, then open /dev/zero and use that to map to. */
190 /* Now try to map in the first page, copy the malloc descriptor structure
191 there, and arrange to return a pointer to this new copy. If the mapping
192 fails, then close the file descriptor if it was opened by us, and arrange
195 if ((mbase = mmorecore(mdp, sizeof(mtemp))) != NULL) {
196 memcpy(mbase, mdp, sizeof(mtemp));
198 fprintf(stderr, "morecore failed to get some more memory!\n");
202 /* Add the new heap to the linked list of heaps attached by mmalloc */
203 if(__mmalloc_default_mdp){
204 mdp = __mmalloc_default_mdp;
205 while(mdp->next_mdesc)
206 mdp = mdp->next_mdesc;
209 mdp->next_mdesc = (struct mdesc *)mbase;
218 /** Terminate access to a mmalloc managed region, but do not free its content.
220 * This is for example useful for the base region where ldl stores its data
221 * because it leaves the place after us.
223 void xbt_mheap_destroy_no_free(xbt_mheap_t md)
225 struct mdesc *mdp = md;
227 if(--mdp->refcount == 0){
229 sem_destroy(&mdp->sem);
233 /** Terminate access to a mmalloc managed region by unmapping all memory pages
234 associated with the region, and closing the file descriptor if it is one
237 Returns NULL on success.
239 Returns the malloc descriptor on failure, which can subsequently be used
240 for further action, such as obtaining more information about the nature of
243 Note that the malloc descriptor that we are using is currently located in
244 region we are about to unmap, so we first make a local copy of it on the
245 stack and use the copy. */
247 void *xbt_mheap_destroy(xbt_mheap_t mdp)
249 struct mdesc mtemp, *mdptemp;
252 /* Remove the heap from the linked list of heaps attached by mmalloc */
253 mdptemp = __mmalloc_default_mdp;
254 while(mdptemp->next_mdesc != mdp )
255 mdptemp = mdptemp->next_mdesc;
257 mdptemp->next_mdesc = mdp->next_mdesc;
259 xbt_mheap_destroy_no_free(mdp);
262 /* Now unmap all the pages associated with this region by asking for a
263 negative increment equal to the current size of the region. */
265 if (mmorecore(&mtemp, (char *)mtemp.base - (char *)mtemp.breakval) == NULL) {
266 /* Deallocating failed. Update the original malloc descriptor
270 if (mtemp.flags & MMALLOC_DEVZERO) {
280 /* Safety gap from the heap's break address.
281 * Try to increase this first if you experience strange errors under
283 #define HEAP_OFFSET (128UL<<20)
285 xbt_mheap_t mmalloc_get_default_md(void)
287 xbt_assert(__mmalloc_default_mdp);
288 return __mmalloc_default_mdp;
291 static void mmalloc_fork_prepare(void)
293 xbt_mheap_t mdp = NULL;
294 if ((mdp =__mmalloc_default_mdp)){
300 mdp = mdp->next_mdesc;
305 static void mmalloc_fork_parent(void)
307 xbt_mheap_t mdp = NULL;
308 if ((mdp =__mmalloc_default_mdp)){
312 mdp = mdp->next_mdesc;
317 static void mmalloc_fork_child(void)
319 struct mdesc* mdp = NULL;
320 if ((mdp =__mmalloc_default_mdp)){
323 mdp = mdp->next_mdesc;
328 /* Initialize the default malloc descriptor. */
329 void *mmalloc_preinit(void)
332 if (__mmalloc_default_mdp == NULL) {
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 #if defined(HAVE_GNU_LD) && defined(MMALLOC_WANT_OVERRIDE_LEGACY)
347 mm_gnuld_legacy_init();
350 return __mmalloc_default_mdp;
353 void mmalloc_postexit(void)
355 /* Do not destroy the default mdp or ldl won't be able to free the memory it
356 * allocated since we're in memory */
357 // xbt_mheap_destroy_no_free(__mmalloc_default_mdp);
360 size_t mmalloc_get_bytes_used(xbt_mheap_t heap){
364 while(i<=((struct mdesc *)heap)->heaplimit){
365 if(((struct mdesc *)heap)->heapinfo[i].type == 0){
366 if(((struct mdesc *)heap)->heapinfo[i].busy_block.busy_size > 0)
367 bytes += ((struct mdesc *)heap)->heapinfo[i].busy_block.busy_size;
369 }else if(((struct mdesc *)heap)->heapinfo[i].type > 0){
370 for(j=0; j < (size_t) (BLOCKSIZE >> ((struct mdesc *)heap)->heapinfo[i].type); j++){
371 if(((struct mdesc *)heap)->heapinfo[i].busy_frag.frag_size[j] > 0)
372 bytes += ((struct mdesc *)heap)->heapinfo[i].busy_frag.frag_size[j];
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 == -1)
386 else if(heap->heapinfo[block].type == 0)
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];