Mercurial > pub > dyncall > dyncall
view dyncallback/dyncall_alloc_wx_mmap.c @ 414:49b669422ad8
- introducing version number
- todo cleanup
author | Tassilo Philipp |
---|---|
date | Thu, 16 Dec 2021 15:58:03 +0100 |
parents | f5577f6bf97a |
children |
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/* Package: dyncall Library: dyncallback File: dyncallback/dyncall_alloc_wx_mmap.c Description: Allocate write/executable memory - Implementation for posix License: Copyright (c) 2007-2018 Daniel Adler <dadler@uni-goettingen.de>, Tassilo Philipp <tphilipp@potion-studios.com> Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include "dyncall_alloc_wx.h" #include <sys/types.h> #include <sys/mman.h> /* MAP_ANON is not POSIX, if lacking, we'll use a portable fallback on *nix systems */ #if !defined(MAP_ANON) # if defined(MAP_ANONYMOUS) # define MAP_ANON MAP_ANONYMOUS # elif defined(DC_UNIX) # include <fcntl.h> # else # error "Platform implementation missing for anonymous rwx memory" # endif #endif /* platforms without mprotect */ #if defined(DC__OS_Minix) # define NO_MPROTECT #endif /* if no mprotect() available/wanted, make mmap alloc pages as rwx */ #if defined(NO_MPROTECT) # define MMAP_PROT_INIT (PROT_READ|PROT_WRITE|PROT_EXEC) #else # define MMAP_PROT_INIT (PROT_READ|PROT_WRITE) #endif DCerror dcAllocWX(size_t size, void** pp) { void* p; #if !defined(MAP_ANON) && defined(DC_UNIX) /* Hack around not having POSIX' MAP_ANON by going through /dev/zero; store file descr to close on dcFreeWX at beginning of memory, as tiny hack */ int fd = open("/dev/zero", O_RDWR); if(fd == -1) return -1; p = mmap(0, size+sizeof(int), MMAP_PROT_INIT, MAP_PRIVATE, fd, 0); if(p == MAP_FAILED) { close(fd); return -1; } *(int*)p = fd; p += sizeof(int); #else p = mmap(0, size, MMAP_PROT_INIT, MAP_PRIVATE|MAP_ANON, -1, 0); if(p == MAP_FAILED) return -1; #endif *pp = p; return 0; } DCerror dcInitExecWX(void* p, size_t size) { #if defined(NO_MPROTECT) return 0; #else #if !defined(MAP_ANON) && defined(DC_UNIX) /* Fixup pointer for no-MAP_ANON workaround (see above) */ p -= sizeof(int); size += sizeof(int); #endif return mprotect(p, size, PROT_READ|PROT_EXEC); #endif } void dcFreeWX(void* p, size_t size) { #if !defined(MAP_ANON) && defined(DC_UNIX) /* Close file descriptor for no-MAP_ANON workaround (see above) */ p -= sizeof(int); size += sizeof(int); close(*(int*)p); #endif munmap(p, size); }