X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/f2df13795e01302813a6aef10825ec7e922ce530..bf71c3c42ec41053cf17711276bfd40d9b3a93c1:/src/xbt/mmalloc/mmorecore.c diff --git a/src/xbt/mmalloc/mmorecore.c b/src/xbt/mmalloc/mmorecore.c index 014b8b81c2..354e40b405 100644 --- a/src/xbt/mmalloc/mmorecore.c +++ b/src/xbt/mmalloc/mmorecore.c @@ -1,7 +1,4 @@ -/* Support for an sbrk-like function that uses mmap. - Copyright 1992, 2000 Free Software Foundation, Inc. - - Contributed by Fred Fish at Cygnus Support. fnf@cygnus.com */ +/* Support for an sbrk-like function that uses mmap. */ /* Copyright (c) 2010-2014. The SimGrid Team. * All rights reserved. */ @@ -9,20 +6,26 @@ /* 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 /* Prototypes for lseek */ #endif #include #include #include #include +#include #include "mmprivate.h" +#ifndef MAP_ANONYMOUS +#define MAP_ANONYMOUS MAP_ANON +#endif + #define PAGE_ALIGN(addr) (void*) (((long)(addr) + xbt_pagesize - 1) & \ ~((long)xbt_pagesize - 1)) @@ -42,59 +45,62 @@ ? -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 (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() */ @@ -106,16 +112,17 @@ void *mmorecore(struct mdesc *mdp, ssize_t size) } } - /* 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); @@ -126,12 +133,13 @@ void *mmorecore(struct mdesc *mdp, ssize_t size) 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);