-/* 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) 2010-2014. The SimGrid Team.
+/* Copyright (c) 2010-2022. 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
-#include <unistd.h> /* Prototypes for lseek */
-#endif
+ Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com */
+
+#include "src/internal_config.h"
#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;
-
-#define PAGE_ALIGN(addr) (void*) (((long)(addr) + pagesize - 1) & \
- ~(pagesize - 1))
-
-/* Return MAP_PRIVATE if MDP represents /dev/zero. Otherwise, return
- MAP_SHARED. */
-#define MAP_PRIVATE_OR_SHARED(MDP) (( MDP -> flags & MMALLOC_ANONYMOUS) \
- ? MAP_PRIVATE \
- : MAP_SHARED)
-
-/* Return MAP_ANONYMOUS if MDP uses anonymous mapping. Otherwise, return 0 */
-#define MAP_IS_ANONYMOUS(MDP) (((MDP) -> flags & MMALLOC_ANONYMOUS) \
- ? MAP_ANONYMOUS \
- : 0)
-
-/* Return -1 if MDP uses anonymous mapping. Otherwise, return MDP->FD */
-#define MAP_ANON_OR_FD(MDP) (((MDP) -> flags & MMALLOC_ANONYMOUS) \
- ? -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. */
+#ifndef MAP_ANONYMOUS
+#define MAP_ANONYMOUS MAP_ANON
+#endif
+#define PAGE_ALIGN(addr) (void*) (((long)(addr) + xbt_pagesize - 1) & \
+ ~((long)xbt_pagesize - 1))
+
+/** @brief Add memory 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
- off_t foffset; /* File offset at which new mapping will start */
+ void* result; // please keep it uninitialized to track issues
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 */
- 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();
+ void* moveto; /* Address where we wish to move "break value" to */
+ void* mapto; /* Address we actually mapped to */
if (size == 0) {
/* Just return the current "break" value. */
- result = mdp->breakval;
+ return 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;
+ 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 = 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. */
- 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);
+ } 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;
+
+ /* 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 | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+
+ if (mapto == MAP_FAILED) {
+ char buff[1024];
+ fprintf(stderr, "Internal error: mmap returned MAP_FAILED! error: %s\n", strerror(errno));
+ 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);
+ sleep(1);
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;
-
- if (mdp->fd > 0) {
- /* FIXME: Test results of lseek() */
- lseek(mdp->fd, foffset + mapbytes - 1, SEEK_SET);
- test = write(mdp->fd, &buf, 1);
- if (test == -1) {
- fprintf(stderr,"Internal error: write to mmap'ed fd failed! error: %s", strerror(errno));
- abort();
- }
- }
-
- /* Let's call mmap. Note that it is possible that mdp->top
- is 0. In this case mmap will choose the address for us */
- 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);
-
- if (mapto == (void *) -1/* That's 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());
- int status = system(buff);
- if (status == -1 || !(WIFEXITED(status) && WEXITSTATUS(status) == 0))
- fprintf(stderr, "Something went wrong when trying to %s\n", buff);
- sleep(1);
- abort();
- }
-
- if (mdp->top == 0)
- mdp->base = mdp->breakval = mapto;
-
- mdp->top = PAGE_ALIGN((char *) mdp->breakval + size);
- result = (void *) mdp->breakval;
- mdp->breakval = (char *) mdp->breakval + size;
- } else {
- result = (void *) mdp->breakval;
- mdp->breakval = (char *) mdp->breakval + size;
}
- }
- return (result);
-}
-void *__mmalloc_remap_core(xbt_mheap_t mdp)
-{
- /* FIXME: Quick hack, needs error checking and other attention. */
+ if (mdp->top == 0)
+ mdp->base = mdp->breakval = mapto;
- return mmap(mdp->base, (char*) mdp->top - (char*) mdp->base,
- PROT_READ | PROT_WRITE | PROT_EXEC,
- MAP_PRIVATE_OR_SHARED(mdp) | MAP_FIXED, mdp->fd, 0);
+ mdp->top = PAGE_ALIGN((char*)mdp->breakval + size);
+ result = mdp->breakval;
+ mdp->breakval = (char*)mdp->breakval + size;
+ } else {
+ /* Memory is already mapped, we only need to increase the breakval: */
+ result = mdp->breakval;
+ mdp->breakval = (char*)mdp->breakval + size;
+ }
+ return result;
}
-
