src/Unix/vm_alloc.cpp

/*
 *  vm_alloc.cpp - Wrapper to various virtual memory allocation schemes
 *                 (supports mmap, vm_allocate or fallbacks to malloc)
 *
 *  Basilisk II (C) 1997-2008 Christian Bauer
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#ifdef HAVE_WIN32_VM
#define WIN32_LEAN_AND_MEAN /* avoid including junk */
#include <windows.h>
#endif

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include "vm_alloc.h"

#ifdef HAVE_MACH_VM
#ifndef HAVE_MACH_TASK_SELF
#ifdef HAVE_TASK_SELF
#define mach_task_self task_self
#else
#error "No task_self(), you lose."
#endif
#endif
#endif

#ifdef HAVE_WIN32_VM
/* Windows is either ILP32 or LLP64 */
typedef UINT_PTR vm_uintptr_t;
#else
/* Other systems are sane as they are either ILP32 or LP64 */
typedef unsigned long vm_uintptr_t;
#endif

/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII
   because the emulated target is 32-bit and this helps to allocate
   memory so that branches could be resolved more easily (32-bit
   displacement to code in .text), on AMD64 for example.  */
#if defined(__hpux)
#define MAP_32BIT MAP_ADDR32
#endif
#ifndef MAP_32BIT
#define MAP_32BIT 0
#endif
#ifndef MAP_ANON
#define MAP_ANON 0
#endif
#ifndef MAP_ANONYMOUS
#define MAP_ANONYMOUS 0
#endif

#define MAP_EXTRA_FLAGS (MAP_32BIT)

#ifdef HAVE_MMAP_VM
#if (defined(__linux__) && defined(__i386__)) || HAVE_LINKER_SCRIPT
/* Force a reasonnable address below 0x80000000 on x86 so that we
   don't get addresses above when the program is run on AMD64.
   NOTE: this is empirically determined on Linux/x86.  */
#define MAP_BASE        0x10000000
#else
#define MAP_BASE        0x00000000
#endif
static char * next_address = (char *)MAP_BASE;
#ifdef HAVE_MMAP_ANON
#define map_flags       (MAP_ANON | MAP_EXTRA_FLAGS)
#define zero_fd         -1
#else
#ifdef HAVE_MMAP_ANONYMOUS
#define map_flags       (MAP_ANONYMOUS | MAP_EXTRA_FLAGS)
#define zero_fd         -1
#else
#define map_flags       (MAP_EXTRA_FLAGS)
static int zero_fd      = -1;
#endif
#endif
#endif

/* Translate generic VM map flags to host values.  */

#ifdef HAVE_MMAP_VM
static int translate_map_flags(int vm_flags)
{
        int flags = 0;
        if (vm_flags & VM_MAP_SHARED)
                flags |= MAP_SHARED;
        if (vm_flags & VM_MAP_PRIVATE)
                flags |= MAP_PRIVATE;
        if (vm_flags & VM_MAP_FIXED)
                flags |= MAP_FIXED;
        if (vm_flags & VM_MAP_32BIT)
                flags |= MAP_32BIT;
        return flags;
}
#endif

/* Align ADDR and SIZE to 64K boundaries.  */

#ifdef HAVE_WIN32_VM
static inline LPVOID align_addr_segment(LPVOID addr)
{
        return (LPVOID)(((vm_uintptr_t)addr) & -((vm_uintptr_t)65536));
}

static inline DWORD align_size_segment(LPVOID addr, DWORD size)
{
        return size + ((vm_uintptr_t)addr - (vm_uintptr_t)align_addr_segment(addr));
}
#endif

/* Translate generic VM prot flags to host values.  */

#ifdef HAVE_WIN32_VM
static int translate_prot_flags(int prot_flags)
{
        int prot = PAGE_READWRITE;
        if (prot_flags == (VM_PAGE_EXECUTE | VM_PAGE_READ | VM_PAGE_WRITE))
                prot = PAGE_EXECUTE_READWRITE;
        else if (prot_flags == (VM_PAGE_EXECUTE | VM_PAGE_READ))
                prot = PAGE_EXECUTE_READ;
        else if (prot_flags == (VM_PAGE_READ | VM_PAGE_WRITE))
                prot = PAGE_READWRITE;
        else if (prot_flags == VM_PAGE_READ)
                prot = PAGE_READONLY;
        else if (prot_flags == 0)
                prot = PAGE_NOACCESS;
        return prot;
}
#endif

/* Translate Mach return codes to POSIX errno values. */
#ifdef HAVE_MACH_VM
static int vm_error(kern_return_t ret_code)
{
        switch (ret_code) {
                case KERN_SUCCESS:
                        return 0;
                case KERN_INVALID_ADDRESS:
                case KERN_NO_SPACE:
                        return ENOMEM;
                case KERN_PROTECTION_FAILURE:
                        return EACCES;
                default:
                        return EINVAL;
        }
}
#endif

/* Initialize the VM system. Returns 0 if successful, -1 for errors.  */

int vm_init(void)
{
#ifdef HAVE_MMAP_VM
#ifndef zero_fd
        zero_fd = open("/dev/zero", O_RDWR);
        if (zero_fd < 0)
                return -1;
#endif
#endif
        return 0;
}

/* Deallocate all internal data used to wrap virtual memory allocators.  */

void vm_exit(void)
{
#ifdef HAVE_MMAP_VM
#ifndef zero_fd
        if (zero_fd != -1) {
                close(zero_fd);
                zero_fd = -1;
        }
#endif
#endif
}

/* Allocate zero-filled memory of SIZE bytes. The mapping is private
   and default protection bits are read / write. The return value
   is the actual mapping address chosen or VM_MAP_FAILED for errors.  */

void * vm_acquire(size_t size, int options)
{
        void * addr;
        
        errno = 0;

        // VM_MAP_FIXED are to be used with vm_acquire_fixed() only
        if (options & VM_MAP_FIXED)
                return VM_MAP_FAILED;

#ifndef HAVE_VM_WRITE_WATCH
        if (options & VM_MAP_WRITE_WATCH)
                return VM_MAP_FAILED;
#endif

#ifdef HAVE_MACH_VM
        // vm_allocate() returns a zero-filled memory region
        kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE);
        if (ret_code != KERN_SUCCESS) {
                errno = vm_error(ret_code);
                return VM_MAP_FAILED;
        }
#else
#ifdef HAVE_MMAP_VM
        int fd = zero_fd;
        int the_map_flags = translate_map_flags(options) | map_flags;

        if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED)
                return VM_MAP_FAILED;
        
        // Sanity checks for 64-bit platforms
        if (sizeof(void *) == 8 && (options & VM_MAP_32BIT) && !((char *)addr <= (char *)0xffffffff))
                return VM_MAP_FAILED;

        next_address = (char *)addr + size;
#else
#ifdef HAVE_WIN32_VM
        int alloc_type = MEM_RESERVE | MEM_COMMIT;
        if (options & VM_MAP_WRITE_WATCH)
          alloc_type |= MEM_WRITE_WATCH;

        if ((addr = VirtualAlloc(NULL, size, alloc_type, PAGE_EXECUTE_READWRITE)) == NULL)
                return VM_MAP_FAILED;
#else
        if ((addr = calloc(size, 1)) == 0)
                return VM_MAP_FAILED;
        
        // Omit changes for protections because they are not supported in this mode
        return addr;
#endif
#endif
#endif

        // Explicitely protect the newly mapped region here because on some systems,
        // say MacOS X, mmap() doesn't honour the requested protection flags.
        if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
                return VM_MAP_FAILED;
        
        return addr;
}

/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
   Retuns 0 if successful, -1 on errors.  */

int vm_acquire_fixed(void * addr, size_t size, int options)
{
        errno = 0;
        
        // Fixed mappings are required to be private
        if (options & VM_MAP_SHARED)
                return -1;

#ifndef HAVE_VM_WRITE_WATCH
        if (options & VM_MAP_WRITE_WATCH)
                return -1;
#endif

#ifdef HAVE_MACH_VM
        // vm_allocate() returns a zero-filled memory region
        kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0);
        if (ret_code != KERN_SUCCESS) {
                errno = vm_error(ret_code);
                return -1;
        }
#else
#ifdef HAVE_MMAP_VM
        int fd = zero_fd;
        int the_map_flags = translate_map_flags(options) | map_flags | MAP_FIXED;

        if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED)
                return -1;
#else
#ifdef HAVE_WIN32_VM
        // Windows cannot allocate Low Memory
        if (addr == NULL)
                return -1;

        int alloc_type = MEM_RESERVE | MEM_COMMIT;
        if (options & VM_MAP_WRITE_WATCH)
          alloc_type |= MEM_WRITE_WATCH;

        // Allocate a possibly offset region to align on 64K boundaries
        LPVOID req_addr = align_addr_segment(addr);
        DWORD  req_size = align_size_segment(addr, size);
        LPVOID ret_addr = VirtualAlloc(req_addr, req_size, alloc_type, PAGE_EXECUTE_READWRITE);
        if (ret_addr != req_addr)
                return -1;
#else
        // Unsupported
        return -1;
#endif
#endif
#endif
        
        // Explicitely protect the newly mapped region here because on some systems,
        // say MacOS X, mmap() doesn't honour the requested protection flags.
        if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
                return -1;
        
        return 0;
}

/* Deallocate any mapping for the region starting at ADDR and extending
   LEN bytes. Returns 0 if successful, -1 on errors.  */

int vm_release(void * addr, size_t size)
{
        // Safety check: don't try to release memory that was not allocated
        if (addr == VM_MAP_FAILED)
                return 0;

#ifdef HAVE_MACH_VM
        if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
                return -1;
#else
#ifdef HAVE_MMAP_VM
        if (munmap((caddr_t)addr, size) != 0)
                return -1;
#else
#ifdef HAVE_WIN32_VM
        if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0)
                return -1;
#else
        free(addr);
#endif
#endif
#endif
        
        return 0;
}

/* Change the memory protection of the region starting at ADDR and
   extending LEN bytes to PROT. Returns 0 if successful, -1 for errors.  */

int vm_protect(void * addr, size_t size, int prot)
{
#ifdef HAVE_MACH_VM
        int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
        return ret_code == KERN_SUCCESS ? 0 : -1;
#else
#ifdef HAVE_MMAP_VM
        int ret_code = mprotect((caddr_t)addr, size, prot);
        return ret_code == 0 ? 0 : -1;
#else
#ifdef HAVE_WIN32_VM
        DWORD old_prot;
        int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot);
        return ret_code != 0 ? 0 : -1;
#else
        // Unsupported
        return -1;
#endif
#endif
#endif
}

/* Return the addresses of the pages that got modified in the
   specified range [ ADDR, ADDR + SIZE [ since the last reset of the watch
   bits. Returns 0 if successful, -1 for errors.  */

int vm_get_write_watch(void * addr, size_t size,
                                           void ** pages, unsigned int * n_pages,
                                           int options)
{
#ifdef HAVE_VM_WRITE_WATCH
#ifdef HAVE_WIN32_VM
        DWORD flags = 0;
        if (options & VM_WRITE_WATCH_RESET)
                flags |= WRITE_WATCH_FLAG_RESET;

        ULONG page_size;
        ULONG_PTR count = *n_pages;
        int ret_code = GetWriteWatch(flags, addr, size, pages, &count, &page_size);
        if (ret_code != 0)
                return -1;

        *n_pages = count;
        return 0;
#endif
#endif
        // Unsupported
        return -1;
}

/* Reset the write-tracking state for the specified range [ ADDR, ADDR
   + SIZE [. Returns 0 if successful, -1 for errors.  */

int vm_reset_write_watch(void * addr, size_t size)
{
#ifdef HAVE_VM_WRITE_WATCH
#ifdef HAVE_WIN32_VM
        int ret_code = ResetWriteWatch(addr, size);
        return ret_code == 0 ? 0 : -1;
#endif
#endif
        // Unsupported
        return -1;
}

/* Returns the size of a page.  */

int vm_get_page_size(void)
{
#ifdef HAVE_WIN32_VM
        static vm_uintptr_t page_size = 0;
        if (page_size == 0) {
                SYSTEM_INFO si;
                GetSystemInfo(&si);
                page_size = si.dwAllocationGranularity;
        }
        return page_size;
#else
        return getpagesize();
#endif
}

#ifdef CONFIGURE_TEST_VM_WRITE_WATCH
int main(void)
{
        int i, j;

        vm_init();

        vm_uintptr_t page_size = vm_get_page_size();
        
        char *area;
        const int n_pages = 7;
        const int area_size = n_pages * page_size;
        const int map_options = VM_MAP_DEFAULT | VM_MAP_WRITE_WATCH;
        if ((area = (char *)vm_acquire(area_size, map_options)) == VM_MAP_FAILED)
                return 1;

        unsigned int n_modified_pages_expected = 0;
        static const int touch_page[n_pages] = { 0, 1, 1, 0, 1, 0, 1 };
        for (i = 0; i < n_pages; i++) {
                if (touch_page[i]) {
                        area[i * page_size] = 1;
                        ++n_modified_pages_expected;
                }
        }

        char *modified_pages[n_pages];
        unsigned int n_modified_pages = n_pages;
        if (vm_get_write_watch(area, area_size, (void **)modified_pages, &n_modified_pages) < 0)
                return 2;
        if (n_modified_pages != n_modified_pages_expected)
                return 3;
        for (i = 0, j = 0; i < n_pages; i++) {
                char v = area[i * page_size];
                if ((touch_page[i] && !v) || (!touch_page[i] && v))
                        return 4;
                if (!touch_page[i])
                        continue;
                if (modified_pages[j] != (area + i * page_size))
                        return 5;
                ++j;
        }

        vm_release(area, area_size);
        return 0;
}
#endif

#ifdef CONFIGURE_TEST_VM_MAP
#include <stdlib.h>
#include <signal.h>

static void fault_handler(int sig)
{
        exit(1);
}

/* Tests covered here:
   - TEST_VM_PROT_* program slices actually succeeds when a crash occurs
   - TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
*/
int main(void)
{
        vm_init();

        signal(SIGSEGV, fault_handler);
#ifdef SIGBUS
        signal(SIGBUS,  fault_handler);
#endif
        
#define page_align(address) ((char *)((vm_uintptr_t)(address) & -page_size))
        vm_uintptr_t page_size = vm_get_page_size();
        
        const int area_size = 6 * page_size;
        volatile char * area = (volatile char *) vm_acquire(area_size);
        volatile char * fault_address = area + (page_size * 7) / 2;

#if defined(TEST_VM_MMAP_ANON) || defined(TEST_VM_MMAP_ANONYMOUS)
        if (area == VM_MAP_FAILED)
                return 1;

        if (vm_release((char *)area, area_size) < 0)
                return 1;
        
        return 0;
#endif

#if defined(TEST_VM_PROT_NONE_READ) || defined(TEST_VM_PROT_NONE_WRITE)
        if (area == VM_MAP_FAILED)
                return 0;
        
        if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
                return 0;
#endif

#if defined(TEST_VM_PROT_RDWR_WRITE)
        if (area == VM_MAP_FAILED)
                return 1;
        
        if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
                return 1;
        
        if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ | VM_PAGE_WRITE) < 0)
                return 1;
#endif

#if defined(TEST_VM_PROT_READ_WRITE)
        if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
                return 0;
#endif

#if defined(TEST_VM_PROT_NONE_READ)
        // this should cause a core dump
        char foo = *fault_address;
        return 0;
#endif

#if defined(TEST_VM_PROT_NONE_WRITE) || defined(TEST_VM_PROT_READ_WRITE)
        // this should cause a core dump
        *fault_address = 'z';
        return 0;
#endif

#if defined(TEST_VM_PROT_RDWR_WRITE)
        // this should not cause a core dump
        *fault_address = 'z';
        return 0;
#endif
}
#endif
Revision:	1.32
Committed:	2009-08-11T07:43:46Z (14 years, 9 months ago) by asvitkine
Branch:	MAIN
Changes since 1.31:	+31 -2 lines
Log Message:	[Michael Schmitt] SheepShaver includes the C errno string in many error messages. One case is when it calls the memory allocation routines in the Basilisk II vm_alloc.cpp program. This works when the memory allocation routine uses functions that set errno (such as mmap or malloc). For example, running SheepShaver on a Linux hosts produces meaningful error messages. The problem is that when run on an OS X host, the memory allocation uses Mach routines such as vm_allocate, which do not set errno. So when SheepShaver reported the error, it used a stale value of errno, which happened to be 17. The result was an extremely misleading error message: "Cannot map RAM: File already exists". The fix is to change vm_alloc so that it translates Mac return codes into POSIX errno values. It also initializes errno to 0 at the start of the memory allocation routine, so that no matter what path it takes, it won't return a stale value.
#	User	Rev	Content
1	gbeauche	1.1	/*
2			* vm_alloc.cpp - Wrapper to various virtual memory allocation schemes
3			* (supports mmap, vm_allocate or fallbacks to malloc)
4			*
5	gbeauche	1.27	* Basilisk II (C) 1997-2008 Christian Bauer
6	gbeauche	1.1	*
7			* This program is free software; you can redistribute it and/or modify
8			* it under the terms of the GNU General Public License as published by
9			* the Free Software Foundation; either version 2 of the License, or
10			* (at your option) any later version.
11			*
12			* This program is distributed in the hope that it will be useful,
13			* but WITHOUT ANY WARRANTY; without even the implied warranty of
14			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15			* GNU General Public License for more details.
16			*
17			* You should have received a copy of the GNU General Public License
18			* along with this program; if not, write to the Free Software
19			* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20			*/
21
22			#ifdef HAVE_CONFIG_H
23			#include "config.h"
24			#endif
25
26	gbeauche	1.13	#ifdef HAVE_FCNTL_H
27			#include <fcntl.h>
28			#endif
29
30	gbeauche	1.14	#ifdef HAVE_WIN32_VM
31			#define WIN32_LEAN_AND_MEAN /* avoid including junk */
32			#include <windows.h>
33			#endif
34
35	asvitkine	1.32	#include <errno.h>
36	gbeauche	1.13	#include <stdio.h>
37	gbeauche	1.1	#include <stdlib.h>
38			#include <string.h>
39	gbeauche	1.13	#include <limits.h>
40	gbeauche	1.1	#include "vm_alloc.h"
41
42			#ifdef HAVE_MACH_VM
43			#ifndef HAVE_MACH_TASK_SELF
44			#ifdef HAVE_TASK_SELF
45			#define mach_task_self task_self
46			#else
47			#error "No task_self(), you lose."
48			#endif
49			#endif
50			#endif
51
52	gbeauche	1.28	#ifdef HAVE_WIN32_VM
53			/* Windows is either ILP32 or LLP64 */
54			typedef UINT_PTR vm_uintptr_t;
55			#else
56			/* Other systems are sane as they are either ILP32 or LP64 */
57			typedef unsigned long vm_uintptr_t;
58			#endif
59
60	gbeauche	1.9	/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII
61			because the emulated target is 32-bit and this helps to allocate
62			memory so that branches could be resolved more easily (32-bit
63			displacement to code in .text), on AMD64 for example. */
64	gbeauche	1.31	#if defined(__hpux)
65			#define MAP_32BIT MAP_ADDR32
66			#endif
67	gbeauche	1.9	#ifndef MAP_32BIT
68			#define MAP_32BIT 0
69			#endif
70	gbeauche	1.13	#ifndef MAP_ANON
71			#define MAP_ANON 0
72			#endif
73			#ifndef MAP_ANONYMOUS
74			#define MAP_ANONYMOUS 0
75			#endif
76	gbeauche	1.9
77			#define MAP_EXTRA_FLAGS (MAP_32BIT)
78
79	gbeauche	1.1	#ifdef HAVE_MMAP_VM
80	gbeauche	1.23	#if (defined(__linux__) && defined(__i386__)) \|\| HAVE_LINKER_SCRIPT
81	gbeauche	1.9	/* Force a reasonnable address below 0x80000000 on x86 so that we
82			don't get addresses above when the program is run on AMD64.
83			NOTE: this is empirically determined on Linux/x86. */
84			#define MAP_BASE 0x10000000
85			#else
86			#define MAP_BASE 0x00000000
87			#endif
88			static char * next_address = (char *)MAP_BASE;
89	gbeauche	1.1	#ifdef HAVE_MMAP_ANON
90	gbeauche	1.10	#define map_flags (MAP_ANON \| MAP_EXTRA_FLAGS)
91	gbeauche	1.1	#define zero_fd -1
92			#else
93			#ifdef HAVE_MMAP_ANONYMOUS
94	gbeauche	1.10	#define map_flags (MAP_ANONYMOUS \| MAP_EXTRA_FLAGS)
95	gbeauche	1.1	#define zero_fd -1
96			#else
97	gbeauche	1.10	#define map_flags (MAP_EXTRA_FLAGS)
98	gbeauche	1.1	static int zero_fd = -1;
99			#endif
100			#endif
101			#endif
102
103	gbeauche	1.10	/* Translate generic VM map flags to host values. */
104
105			#ifdef HAVE_MMAP_VM
106			static int translate_map_flags(int vm_flags)
107			{
108			int flags = 0;
109			if (vm_flags & VM_MAP_SHARED)
110			flags \|= MAP_SHARED;
111			if (vm_flags & VM_MAP_PRIVATE)
112			flags \|= MAP_PRIVATE;
113			if (vm_flags & VM_MAP_FIXED)
114			flags \|= MAP_FIXED;
115			if (vm_flags & VM_MAP_32BIT)
116			flags \|= MAP_32BIT;
117			return flags;
118			}
119			#endif
120
121	gbeauche	1.14	/* Align ADDR and SIZE to 64K boundaries. */
122
123			#ifdef HAVE_WIN32_VM
124			static inline LPVOID align_addr_segment(LPVOID addr)
125			{
126	gbeauche	1.28	return (LPVOID)(((vm_uintptr_t)addr) & -((vm_uintptr_t)65536));
127	gbeauche	1.14	}
128
129			static inline DWORD align_size_segment(LPVOID addr, DWORD size)
130			{
131	gbeauche	1.28	return size + ((vm_uintptr_t)addr - (vm_uintptr_t)align_addr_segment(addr));
132	gbeauche	1.14	}
133			#endif
134
135			/* Translate generic VM prot flags to host values. */
136
137			#ifdef HAVE_WIN32_VM
138			static int translate_prot_flags(int prot_flags)
139			{
140			int prot = PAGE_READWRITE;
141			if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ \| VM_PAGE_WRITE))
142			prot = PAGE_EXECUTE_READWRITE;
143			else if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ))
144			prot = PAGE_EXECUTE_READ;
145			else if (prot_flags == (VM_PAGE_READ \| VM_PAGE_WRITE))
146			prot = PAGE_READWRITE;
147			else if (prot_flags == VM_PAGE_READ)
148			prot = PAGE_READONLY;
149			else if (prot_flags == 0)
150			prot = PAGE_NOACCESS;
151			return prot;
152			}
153			#endif
154
155	asvitkine	1.32	/* Translate Mach return codes to POSIX errno values. */
156			#ifdef HAVE_MACH_VM
157			static int vm_error(kern_return_t ret_code)
158			{
159			switch (ret_code) {
160			case KERN_SUCCESS:
161			return 0;
162			case KERN_INVALID_ADDRESS:
163			case KERN_NO_SPACE:
164			return ENOMEM;
165			case KERN_PROTECTION_FAILURE:
166			return EACCES;
167			default:
168			return EINVAL;
169			}
170			}
171			#endif
172
173	gbeauche	1.1	/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
174
175			int vm_init(void)
176			{
177			#ifdef HAVE_MMAP_VM
178			#ifndef zero_fd
179			zero_fd = open("/dev/zero", O_RDWR);
180			if (zero_fd < 0)
181			return -1;
182			#endif
183			#endif
184			return 0;
185			}
186
187			/* Deallocate all internal data used to wrap virtual memory allocators. */
188
189			void vm_exit(void)
190			{
191			#ifdef HAVE_MMAP_VM
192			#ifndef zero_fd
193	gbeauche	1.19	if (zero_fd != -1) {
194			close(zero_fd);
195			zero_fd = -1;
196			}
197	gbeauche	1.1	#endif
198			#endif
199			}
200
201			/* Allocate zero-filled memory of SIZE bytes. The mapping is private
202			and default protection bits are read / write. The return value
203			is the actual mapping address chosen or VM_MAP_FAILED for errors. */
204
205	gbeauche	1.10	void * vm_acquire(size_t size, int options)
206	gbeauche	1.1	{
207			void * addr;
208	asvitkine	1.32
209			errno = 0;
210	gbeauche	1.10
211			// VM_MAP_FIXED are to be used with vm_acquire_fixed() only
212			if (options & VM_MAP_FIXED)
213			return VM_MAP_FAILED;
214
215	gbeauche	1.29	#ifndef HAVE_VM_WRITE_WATCH
216			if (options & VM_MAP_WRITE_WATCH)
217			return VM_MAP_FAILED;
218			#endif
219
220	gbeauche	1.1	#ifdef HAVE_MACH_VM
221			// vm_allocate() returns a zero-filled memory region
222	asvitkine	1.32	kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE);
223			if (ret_code != KERN_SUCCESS) {
224			errno = vm_error(ret_code);
225	gbeauche	1.1	return VM_MAP_FAILED;
226	asvitkine	1.32	}
227	gbeauche	1.1	#else
228			#ifdef HAVE_MMAP_VM
229	gbeauche	1.13	int fd = zero_fd;
230			int the_map_flags = translate_map_flags(options) \| map_flags;
231
232			if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED)
233	gbeauche	1.1	return VM_MAP_FAILED;
234
235	gbeauche	1.10	// Sanity checks for 64-bit platforms
236			if (sizeof(void ) == 8 && (options & VM_MAP_32BIT) && !((char )addr <= (char *)0xffffffff))
237			return VM_MAP_FAILED;
238
239	gbeauche	1.3	next_address = (char *)addr + size;
240	gbeauche	1.1	#else
241	gbeauche	1.14	#ifdef HAVE_WIN32_VM
242	gbeauche	1.29	int alloc_type = MEM_RESERVE \| MEM_COMMIT;
243			if (options & VM_MAP_WRITE_WATCH)
244			alloc_type \|= MEM_WRITE_WATCH;
245
246			if ((addr = VirtualAlloc(NULL, size, alloc_type, PAGE_EXECUTE_READWRITE)) == NULL)
247	gbeauche	1.14	return VM_MAP_FAILED;
248			#else
249	gbeauche	1.1	if ((addr = calloc(size, 1)) == 0)
250			return VM_MAP_FAILED;
251
252			// Omit changes for protections because they are not supported in this mode
253			return addr;
254			#endif
255			#endif
256	gbeauche	1.14	#endif
257	cebix	1.2
258	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
259			// say MacOS X, mmap() doesn't honour the requested protection flags.
260			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
261			return VM_MAP_FAILED;
262
263			return addr;
264			}
265
266			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
267			Retuns 0 if successful, -1 on errors. */
268
269	gbeauche	1.10	int vm_acquire_fixed(void * addr, size_t size, int options)
270	gbeauche	1.1	{
271	asvitkine	1.32	errno = 0;
272
273	gbeauche	1.10	// Fixed mappings are required to be private
274			if (options & VM_MAP_SHARED)
275			return -1;
276
277	gbeauche	1.29	#ifndef HAVE_VM_WRITE_WATCH
278			if (options & VM_MAP_WRITE_WATCH)
279			return -1;
280			#endif
281
282	gbeauche	1.1	#ifdef HAVE_MACH_VM
283			// vm_allocate() returns a zero-filled memory region
284	asvitkine	1.32	kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0);
285			if (ret_code != KERN_SUCCESS) {
286			errno = vm_error(ret_code);
287	gbeauche	1.1	return -1;
288	asvitkine	1.32	}
289	gbeauche	1.1	#else
290			#ifdef HAVE_MMAP_VM
291	gbeauche	1.21	int fd = zero_fd;
292			int the_map_flags = translate_map_flags(options) \| map_flags \| MAP_FIXED;
293	gbeauche	1.10
294	gbeauche	1.21	if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED)
295	gbeauche	1.1	return -1;
296			#else
297	gbeauche	1.14	#ifdef HAVE_WIN32_VM
298			// Windows cannot allocate Low Memory
299			if (addr == NULL)
300			return -1;
301
302	gbeauche	1.29	int alloc_type = MEM_RESERVE \| MEM_COMMIT;
303			if (options & VM_MAP_WRITE_WATCH)
304			alloc_type \|= MEM_WRITE_WATCH;
305
306	gbeauche	1.14	// Allocate a possibly offset region to align on 64K boundaries
307			LPVOID req_addr = align_addr_segment(addr);
308			DWORD req_size = align_size_segment(addr, size);
309	gbeauche	1.29	LPVOID ret_addr = VirtualAlloc(req_addr, req_size, alloc_type, PAGE_EXECUTE_READWRITE);
310	gbeauche	1.14	if (ret_addr != req_addr)
311			return -1;
312			#else
313	gbeauche	1.1	// Unsupported
314			return -1;
315			#endif
316			#endif
317	gbeauche	1.14	#endif
318	gbeauche	1.1
319			// Explicitely protect the newly mapped region here because on some systems,
320			// say MacOS X, mmap() doesn't honour the requested protection flags.
321	gbeauche	1.6	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
322	gbeauche	1.1	return -1;
323
324			return 0;
325			}
326
327			/* Deallocate any mapping for the region starting at ADDR and extending
328			LEN bytes. Returns 0 if successful, -1 on errors. */
329
330			int vm_release(void * addr, size_t size)
331			{
332	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
333			if (addr == VM_MAP_FAILED)
334			return 0;
335
336	gbeauche	1.1	#ifdef HAVE_MACH_VM
337	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
338			return -1;
339	gbeauche	1.1	#else
340			#ifdef HAVE_MMAP_VM
341	gbeauche	1.7	if (munmap((caddr_t)addr, size) != 0)
342	gbeauche	1.4	return -1;
343	gbeauche	1.1	#else
344	gbeauche	1.14	#ifdef HAVE_WIN32_VM
345			if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0)
346			return -1;
347			#else
348	gbeauche	1.1	free(addr);
349			#endif
350			#endif
351	gbeauche	1.14	#endif
352	gbeauche	1.4
353			return 0;
354	gbeauche	1.1	}
355
356			/* Change the memory protection of the region starting at ADDR and
357			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
358
359			int vm_protect(void * addr, size_t size, int prot)
360			{
361			#ifdef HAVE_MACH_VM
362			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
363			return ret_code == KERN_SUCCESS ? 0 : -1;
364			#else
365			#ifdef HAVE_MMAP_VM
366	gbeauche	1.7	int ret_code = mprotect((caddr_t)addr, size, prot);
367	gbeauche	1.1	return ret_code == 0 ? 0 : -1;
368			#else
369	gbeauche	1.14	#ifdef HAVE_WIN32_VM
370			DWORD old_prot;
371			int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot);
372			return ret_code != 0 ? 0 : -1;
373			#else
374	gbeauche	1.1	// Unsupported
375			return -1;
376			#endif
377			#endif
378	gbeauche	1.14	#endif
379	gbeauche	1.1	}
380
381	gbeauche	1.29	/* Return the addresses of the pages that got modified in the
382			specified range [ ADDR, ADDR + SIZE [ since the last reset of the watch
383			bits. Returns 0 if successful, -1 for errors. */
384
385			int vm_get_write_watch(void * addr, size_t size,
386			void ** pages, unsigned int * n_pages,
387			int options)
388			{
389			#ifdef HAVE_VM_WRITE_WATCH
390			#ifdef HAVE_WIN32_VM
391			DWORD flags = 0;
392			if (options & VM_WRITE_WATCH_RESET)
393			flags \|= WRITE_WATCH_FLAG_RESET;
394
395			ULONG page_size;
396	gbeauche	1.30	ULONG_PTR count = *n_pages;
397	gbeauche	1.29	int ret_code = GetWriteWatch(flags, addr, size, pages, &count, &page_size);
398			if (ret_code != 0)
399			return -1;
400
401			*n_pages = count;
402			return 0;
403			#endif
404			#endif
405			// Unsupported
406			return -1;
407			}
408
409			/* Reset the write-tracking state for the specified range [ ADDR, ADDR
410			+ SIZE [. Returns 0 if successful, -1 for errors. */
411
412			int vm_reset_write_watch(void * addr, size_t size)
413			{
414			#ifdef HAVE_VM_WRITE_WATCH
415			#ifdef HAVE_WIN32_VM
416			int ret_code = ResetWriteWatch(addr, size);
417			return ret_code == 0 ? 0 : -1;
418			#endif
419			#endif
420			// Unsupported
421			return -1;
422			}
423
424	gbeauche	1.15	/* Returns the size of a page. */
425
426	gbeauche	1.16	int vm_get_page_size(void)
427	gbeauche	1.15	{
428	gbeauche	1.20	#ifdef HAVE_WIN32_VM
429	gbeauche	1.28	static vm_uintptr_t page_size = 0;
430	gbeauche	1.20	if (page_size == 0) {
431			SYSTEM_INFO si;
432			GetSystemInfo(&si);
433			page_size = si.dwAllocationGranularity;
434			}
435			return page_size;
436	gbeauche	1.15	#else
437	gbeauche	1.20	return getpagesize();
438	gbeauche	1.15	#endif
439			}
440
441	gbeauche	1.29	#ifdef CONFIGURE_TEST_VM_WRITE_WATCH
442			int main(void)
443			{
444			int i, j;
445
446			vm_init();
447
448			vm_uintptr_t page_size = vm_get_page_size();
449
450			char *area;
451			const int n_pages = 7;
452			const int area_size = n_pages * page_size;
453			const int map_options = VM_MAP_DEFAULT \| VM_MAP_WRITE_WATCH;
454			if ((area = (char *)vm_acquire(area_size, map_options)) == VM_MAP_FAILED)
455			return 1;
456
457			unsigned int n_modified_pages_expected = 0;
458			static const int touch_page[n_pages] = { 0, 1, 1, 0, 1, 0, 1 };
459			for (i = 0; i < n_pages; i++) {
460			if (touch_page[i]) {
461			area[i * page_size] = 1;
462			++n_modified_pages_expected;
463			}
464			}
465
466			char *modified_pages[n_pages];
467			unsigned int n_modified_pages = n_pages;
468			if (vm_get_write_watch(area, area_size, (void **)modified_pages, &n_modified_pages) < 0)
469			return 2;
470			if (n_modified_pages != n_modified_pages_expected)
471			return 3;
472			for (i = 0, j = 0; i < n_pages; i++) {
473			char v = area[i * page_size];
474			if ((touch_page[i] && !v) \|\| (!touch_page[i] && v))
475			return 4;
476			if (!touch_page[i])
477			continue;
478			if (modified_pages[j] != (area + i * page_size))
479			return 5;
480			++j;
481			}
482
483			vm_release(area, area_size);
484			return 0;
485			}
486			#endif
487
488	gbeauche	1.1	#ifdef CONFIGURE_TEST_VM_MAP
489	gbeauche	1.18	#include <stdlib.h>
490			#include <signal.h>
491
492			static void fault_handler(int sig)
493			{
494			exit(1);
495			}
496
497	gbeauche	1.1	/* Tests covered here:
498			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
499			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
500			*/
501			int main(void)
502			{
503			vm_init();
504	gbeauche	1.18
505			signal(SIGSEGV, fault_handler);
506			#ifdef SIGBUS
507			signal(SIGBUS, fault_handler);
508			#endif
509	gbeauche	1.1
510	gbeauche	1.28	#define page_align(address) ((char *)((vm_uintptr_t)(address) & -page_size))
511			vm_uintptr_t page_size = vm_get_page_size();
512	gbeauche	1.1
513			const int area_size = 6 * page_size;
514			volatile char * area = (volatile char *) vm_acquire(area_size);
515			volatile char * fault_address = area + (page_size * 7) / 2;
516
517			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
518			if (area == VM_MAP_FAILED)
519			return 1;
520
521			if (vm_release((char *)area, area_size) < 0)
522			return 1;
523
524			return 0;
525			#endif
526
527			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
528			if (area == VM_MAP_FAILED)
529			return 0;
530
531			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
532			return 0;
533			#endif
534
535			#if defined(TEST_VM_PROT_RDWR_WRITE)
536			if (area == VM_MAP_FAILED)
537			return 1;
538
539			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
540			return 1;
541
542			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
543			return 1;
544			#endif
545
546			#if defined(TEST_VM_PROT_READ_WRITE)
547			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
548			return 0;
549			#endif
550
551			#if defined(TEST_VM_PROT_NONE_READ)
552			// this should cause a core dump
553			char foo = *fault_address;
554			return 0;
555			#endif
556
557			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
558			// this should cause a core dump
559			*fault_address = 'z';
560			return 0;
561			#endif
562
563			#if defined(TEST_VM_PROT_RDWR_WRITE)
564			// this should not cause a core dump
565			*fault_address = 'z';
566			return 0;
567			#endif
568			}
569			#endif