-/* Support for an sbrk-like function that uses mmap.
- Copyright 1992, 2000 Free Software Foundation, Inc.
+/* Support for an sbrk-like function that uses mmap. */
- Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com */
-
-/* Copyright (c) 2010-2012. The SimGrid Team. All rights reserved. */
+/* Copyright (c) 2010-2014. The SimGrid Team.
+ * All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
-#ifndef MAP_ANONYMOUS
-#define MAP_ANONYMOUS MAP_ANON
-#endif
+/* Copyright 1992, 2000 Free Software Foundation, Inc.
-#ifdef HAVE_UNISTD_H
+ Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com */
+
+#include "src/internal_config.h"
+#if HAVE_UNISTD_H
#include <unistd.h> /* Prototypes for lseek */
#endif
#include <stdio.h>
#include <fcntl.h>
#include <sys/mman.h>
+#include <sys/wait.h>
+#include <errno.h>
#include "mmprivate.h"
-/* Cache the pagesize for the current host machine. Note that if the host
- does not readily provide a getpagesize() function, we need to emulate it
- elsewhere, not clutter up this file with lots of kluges to try to figure
- it out. */
-
-static size_t pagesize;
+#ifndef MAP_ANONYMOUS
+#define MAP_ANONYMOUS MAP_ANON
+#endif
-#define PAGE_ALIGN(addr) (void*) (((long)(addr) + pagesize - 1) & \
- ~(pagesize - 1))
+#define PAGE_ALIGN(addr) (void*) (((long)(addr) + xbt_pagesize - 1) & \
+ ~((long)xbt_pagesize - 1))
/* Return MAP_PRIVATE if MDP represents /dev/zero. Otherwise, return
MAP_SHARED. */
? -1 \
: (MDP) -> fd)
-/* Get core for the memory region specified by MDP, using SIZE as the
- amount to either add to or subtract from the existing region. Works
- like sbrk(), but using mmap().
-
- It never returns NULL. Instead, it dies verbosely on errors. */
-
+/* Return 0if MDP uses anonymous mapping. Otherwise, return off */
+#define MAP_ANON_OR_OFFSET(MDP, off) (((MDP) -> flags & MMALLOC_ANONYMOUS) \
+ ? 0 \
+ : off)
+
+/** @brief Add memoty to this heap
+ *
+ * Get core for the memory region specified by MDP, using SIZE as the
+ * amount to either add to or subtract from the existing region. Works
+ * like sbrk(), but using mmap().
+ *
+ * It never returns NULL. Instead, it dies verbosely on errors.
+ *
+ * @param mdp The heap
+ * @param size Bytes to allocate for this heap (or <0 to free memory from this heap)
+ */
void *mmorecore(struct mdesc *mdp, ssize_t size)
{
ssize_t test = 0;
- void *result; // please keep it uninitialized to track issues
+ void* result; // please keep it uninitialized to track issues
off_t foffset; /* File offset at which new mapping will start */
size_t mapbytes; /* Number of bytes to map */
- void *moveto; /* Address where we wish to move "break value" to */
- void *mapto; /* Address we actually mapped to */
+ void* moveto; /* Address where we wish to move "break value" to */
+ void* mapto; /* Address we actually mapped to */
char buf = 0; /* Single byte to write to extend mapped file */
-// fprintf(stderr,"increase %p by %u\n",mdp,size);
- if (pagesize == 0)
- pagesize = getpagesize();
-
if (size == 0) {
/* Just return the current "break" value. */
- result = mdp->breakval;
-
- } else if (size < 0) {
- /* We are deallocating memory. If the amount requested would cause
- us to try to deallocate back past the base of the mmap'd region
- then die verbosely. Otherwise, deallocate the memory and return
- the old break value. */
- if (((char *) mdp->breakval) + size >= (char *) mdp->base) {
- result = (void *) mdp->breakval;
- mdp->breakval = (char *) mdp->breakval + size;
+ return mdp->breakval;
+ }
+
+ if (size < 0) {
+ /* We are deallocating memory. If the amount requested would cause us to try to deallocate back past the base of
+ * the mmap'd region then die verbosely. Otherwise, deallocate the memory and return the old break value. */
+ if (((char*)mdp->breakval) + size >= (char*)mdp->base) {
+ result = (void*)mdp->breakval;
+ mdp->breakval = (char*)mdp->breakval + size;
moveto = PAGE_ALIGN(mdp->breakval);
- munmap(moveto,
- (size_t) (((char *) mdp->top) - ((char *) moveto)) - 1);
+ munmap(moveto, (size_t)(((char*)mdp->top) - ((char*)moveto)) - 1);
mdp->top = moveto;
} else {
fprintf(stderr,"Internal error: mmap was asked to deallocate more memory than it previously allocated. Bailling out now!\n");
abort();
}
} else {
- /* We are allocating memory. Make sure we have an open file
- descriptor if not working with anonymous memory. */
+ /* We are allocating memory. Make sure we have an open file descriptor if not working with anonymous memory. */
if (!(mdp->flags & MMALLOC_ANONYMOUS) && mdp->fd < 0) {
fprintf(stderr,"Internal error: mmap file descriptor <0 (%d), without MMALLOC_ANONYMOUS being in the flags.\n",mdp->fd);
abort();
- } else if ((char *) mdp->breakval + size > (char *) mdp->top) {
- /* The request would move us past the end of the currently
- mapped memory, so map in enough more memory to satisfy
- the request. This means we also have to grow the mapped-to
- file by an appropriate amount, since mmap cannot be used
- to extend a file. */
- moveto = PAGE_ALIGN((char *) mdp->breakval + size);
- mapbytes = (char *) moveto - (char *) mdp->top;
- foffset = (char *) mdp->top - (char *) mdp->base;
+ } else if ((char*)mdp->breakval + size > (char*)mdp->top) {
+ /* The request would move us past the end of the currently mapped memory, so map in enough more memory to satisfy
+ the request. This means we also have to grow the mapped-to file by an appropriate amount, since mmap cannot
+ be used to extend a file. */
+ moveto = PAGE_ALIGN((char*)mdp->breakval + size);
+ mapbytes = (char*)moveto - (char*)mdp->top;
+ foffset = (char*)mdp->top - (char*)mdp->base;
if (mdp->fd > 0) {
/* FIXME: Test results of lseek() */
}
}
- /* Let's call mmap. Note that it is possible that mdp->top
- is 0. In this case mmap will choose the address for us */
+ /* Let's call mmap. Note that it is possible that mdp->top is 0. In this case mmap will choose the address for us.
+ This call might very well overwrite an already existing memory mapping (leading to weird bugs).
+ */
mapto = mmap(mdp->top, mapbytes, PROT_READ | PROT_WRITE,
MAP_PRIVATE_OR_SHARED(mdp) | MAP_IS_ANONYMOUS(mdp) |
- MAP_FIXED, MAP_ANON_OR_FD(mdp), foffset);
+ MAP_FIXED, MAP_ANON_OR_FD(mdp), MAP_ANON_OR_OFFSET(mdp, foffset));
- if (mapto == (void *) -1/* That's MAP_FAILED */) {
+ if (mapto == MAP_FAILED) {
char buff[1024];
fprintf(stderr,"Internal error: mmap returned MAP_FAILED! error: %s\n",strerror(errno));
- sprintf(buff,"cat /proc/%d/maps",getpid());
+ snprintf(buff,1024,"cat /proc/%d/maps",getpid());
int status = system(buff);
if (status == -1 || !(WIFEXITED(status) && WEXITSTATUS(status) == 0))
fprintf(stderr, "Something went wrong when trying to %s\n", buff);
if (mdp->top == 0)
mdp->base = mdp->breakval = mapto;
- mdp->top = PAGE_ALIGN((char *) mdp->breakval + size);
+ mdp->top = PAGE_ALIGN((char*)mdp->breakval + size);
result = (void *) mdp->breakval;
- mdp->breakval = (char *) mdp->breakval + size;
+ mdp->breakval = (char*)mdp->breakval + size;
} else {
+ /* Memory is already mapped, we only need to increase the breakval: */
result = (void *) mdp->breakval;
- mdp->breakval = (char *) mdp->breakval + size;
+ mdp->breakval = (char*)mdp->breakval + size;
}
}
return (result);
