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 <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.  */
#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

/* 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;

        // 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
        if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
                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)
{
        // 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
        if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
                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 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:	1.29
Committed:	2008-01-16T22:36:35Z (16 years, 6 months ago) by gbeauche
Branch:	MAIN
Changes since 1.28:	+110 -2 lines
Log Message:	Wrap the Windows write-watch API.
#	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	gbeauche	1.13	#include <stdio.h>
36	gbeauche	1.1	#include <stdlib.h>
37			#include <string.h>
38	gbeauche	1.13	#include <limits.h>
39	gbeauche	1.1	#include "vm_alloc.h"
40
41			#ifdef HAVE_MACH_VM
42			#ifndef HAVE_MACH_TASK_SELF
43			#ifdef HAVE_TASK_SELF
44			#define mach_task_self task_self
45			#else
46			#error "No task_self(), you lose."
47			#endif
48			#endif
49			#endif
50
51	gbeauche	1.28	#ifdef HAVE_WIN32_VM
52			/* Windows is either ILP32 or LLP64 */
53			typedef UINT_PTR vm_uintptr_t;
54			#else
55			/* Other systems are sane as they are either ILP32 or LP64 */
56			typedef unsigned long vm_uintptr_t;
57			#endif
58
59	gbeauche	1.9	/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII
60			because the emulated target is 32-bit and this helps to allocate
61			memory so that branches could be resolved more easily (32-bit
62			displacement to code in .text), on AMD64 for example. */
63			#ifndef MAP_32BIT
64			#define MAP_32BIT 0
65			#endif
66	gbeauche	1.13	#ifndef MAP_ANON
67			#define MAP_ANON 0
68			#endif
69			#ifndef MAP_ANONYMOUS
70			#define MAP_ANONYMOUS 0
71			#endif
72	gbeauche	1.9
73			#define MAP_EXTRA_FLAGS (MAP_32BIT)
74
75	gbeauche	1.1	#ifdef HAVE_MMAP_VM
76	gbeauche	1.23	#if (defined(__linux__) && defined(__i386__)) \|\| HAVE_LINKER_SCRIPT
77	gbeauche	1.9	/* Force a reasonnable address below 0x80000000 on x86 so that we
78			don't get addresses above when the program is run on AMD64.
79			NOTE: this is empirically determined on Linux/x86. */
80			#define MAP_BASE 0x10000000
81			#else
82			#define MAP_BASE 0x00000000
83			#endif
84			static char * next_address = (char *)MAP_BASE;
85	gbeauche	1.1	#ifdef HAVE_MMAP_ANON
86	gbeauche	1.10	#define map_flags (MAP_ANON \| MAP_EXTRA_FLAGS)
87	gbeauche	1.1	#define zero_fd -1
88			#else
89			#ifdef HAVE_MMAP_ANONYMOUS
90	gbeauche	1.10	#define map_flags (MAP_ANONYMOUS \| MAP_EXTRA_FLAGS)
91	gbeauche	1.1	#define zero_fd -1
92			#else
93	gbeauche	1.10	#define map_flags (MAP_EXTRA_FLAGS)
94	gbeauche	1.1	static int zero_fd = -1;
95			#endif
96			#endif
97			#endif
98
99	gbeauche	1.10	/* Translate generic VM map flags to host values. */
100
101			#ifdef HAVE_MMAP_VM
102			static int translate_map_flags(int vm_flags)
103			{
104			int flags = 0;
105			if (vm_flags & VM_MAP_SHARED)
106			flags \|= MAP_SHARED;
107			if (vm_flags & VM_MAP_PRIVATE)
108			flags \|= MAP_PRIVATE;
109			if (vm_flags & VM_MAP_FIXED)
110			flags \|= MAP_FIXED;
111			if (vm_flags & VM_MAP_32BIT)
112			flags \|= MAP_32BIT;
113			return flags;
114			}
115			#endif
116
117	gbeauche	1.14	/* Align ADDR and SIZE to 64K boundaries. */
118
119			#ifdef HAVE_WIN32_VM
120			static inline LPVOID align_addr_segment(LPVOID addr)
121			{
122	gbeauche	1.28	return (LPVOID)(((vm_uintptr_t)addr) & -((vm_uintptr_t)65536));
123	gbeauche	1.14	}
124
125			static inline DWORD align_size_segment(LPVOID addr, DWORD size)
126			{
127	gbeauche	1.28	return size + ((vm_uintptr_t)addr - (vm_uintptr_t)align_addr_segment(addr));
128	gbeauche	1.14	}
129			#endif
130
131			/* Translate generic VM prot flags to host values. */
132
133			#ifdef HAVE_WIN32_VM
134			static int translate_prot_flags(int prot_flags)
135			{
136			int prot = PAGE_READWRITE;
137			if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ \| VM_PAGE_WRITE))
138			prot = PAGE_EXECUTE_READWRITE;
139			else if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ))
140			prot = PAGE_EXECUTE_READ;
141			else if (prot_flags == (VM_PAGE_READ \| VM_PAGE_WRITE))
142			prot = PAGE_READWRITE;
143			else if (prot_flags == VM_PAGE_READ)
144			prot = PAGE_READONLY;
145			else if (prot_flags == 0)
146			prot = PAGE_NOACCESS;
147			return prot;
148			}
149			#endif
150
151	gbeauche	1.1	/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
152
153			int vm_init(void)
154			{
155			#ifdef HAVE_MMAP_VM
156			#ifndef zero_fd
157			zero_fd = open("/dev/zero", O_RDWR);
158			if (zero_fd < 0)
159			return -1;
160			#endif
161			#endif
162			return 0;
163			}
164
165			/* Deallocate all internal data used to wrap virtual memory allocators. */
166
167			void vm_exit(void)
168			{
169			#ifdef HAVE_MMAP_VM
170			#ifndef zero_fd
171	gbeauche	1.19	if (zero_fd != -1) {
172			close(zero_fd);
173			zero_fd = -1;
174			}
175	gbeauche	1.1	#endif
176			#endif
177			}
178
179			/* Allocate zero-filled memory of SIZE bytes. The mapping is private
180			and default protection bits are read / write. The return value
181			is the actual mapping address chosen or VM_MAP_FAILED for errors. */
182
183	gbeauche	1.10	void * vm_acquire(size_t size, int options)
184	gbeauche	1.1	{
185			void * addr;
186	gbeauche	1.10
187			// VM_MAP_FIXED are to be used with vm_acquire_fixed() only
188			if (options & VM_MAP_FIXED)
189			return VM_MAP_FAILED;
190
191	gbeauche	1.29	#ifndef HAVE_VM_WRITE_WATCH
192			if (options & VM_MAP_WRITE_WATCH)
193			return VM_MAP_FAILED;
194			#endif
195
196	gbeauche	1.1	#ifdef HAVE_MACH_VM
197			// vm_allocate() returns a zero-filled memory region
198			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
199			return VM_MAP_FAILED;
200			#else
201			#ifdef HAVE_MMAP_VM
202	gbeauche	1.13	int fd = zero_fd;
203			int the_map_flags = translate_map_flags(options) \| map_flags;
204
205			if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED)
206	gbeauche	1.1	return VM_MAP_FAILED;
207
208	gbeauche	1.10	// Sanity checks for 64-bit platforms
209			if (sizeof(void ) == 8 && (options & VM_MAP_32BIT) && !((char )addr <= (char *)0xffffffff))
210			return VM_MAP_FAILED;
211
212	gbeauche	1.3	next_address = (char *)addr + size;
213	gbeauche	1.1	#else
214	gbeauche	1.14	#ifdef HAVE_WIN32_VM
215	gbeauche	1.29	int alloc_type = MEM_RESERVE \| MEM_COMMIT;
216			if (options & VM_MAP_WRITE_WATCH)
217			alloc_type \|= MEM_WRITE_WATCH;
218
219			if ((addr = VirtualAlloc(NULL, size, alloc_type, PAGE_EXECUTE_READWRITE)) == NULL)
220	gbeauche	1.14	return VM_MAP_FAILED;
221			#else
222	gbeauche	1.1	if ((addr = calloc(size, 1)) == 0)
223			return VM_MAP_FAILED;
224
225			// Omit changes for protections because they are not supported in this mode
226			return addr;
227			#endif
228			#endif
229	gbeauche	1.14	#endif
230	cebix	1.2
231	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
232			// say MacOS X, mmap() doesn't honour the requested protection flags.
233			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
234			return VM_MAP_FAILED;
235
236			return addr;
237			}
238
239			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
240			Retuns 0 if successful, -1 on errors. */
241
242	gbeauche	1.10	int vm_acquire_fixed(void * addr, size_t size, int options)
243	gbeauche	1.1	{
244	gbeauche	1.10	// Fixed mappings are required to be private
245			if (options & VM_MAP_SHARED)
246			return -1;
247
248	gbeauche	1.29	#ifndef HAVE_VM_WRITE_WATCH
249			if (options & VM_MAP_WRITE_WATCH)
250			return -1;
251			#endif
252
253	gbeauche	1.1	#ifdef HAVE_MACH_VM
254			// vm_allocate() returns a zero-filled memory region
255			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
256			return -1;
257			#else
258			#ifdef HAVE_MMAP_VM
259	gbeauche	1.21	int fd = zero_fd;
260			int the_map_flags = translate_map_flags(options) \| map_flags \| MAP_FIXED;
261	gbeauche	1.10
262	gbeauche	1.21	if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED)
263	gbeauche	1.1	return -1;
264			#else
265	gbeauche	1.14	#ifdef HAVE_WIN32_VM
266			// Windows cannot allocate Low Memory
267			if (addr == NULL)
268			return -1;
269
270	gbeauche	1.29	int alloc_type = MEM_RESERVE \| MEM_COMMIT;
271			if (options & VM_MAP_WRITE_WATCH)
272			alloc_type \|= MEM_WRITE_WATCH;
273
274	gbeauche	1.14	// Allocate a possibly offset region to align on 64K boundaries
275			LPVOID req_addr = align_addr_segment(addr);
276			DWORD req_size = align_size_segment(addr, size);
277	gbeauche	1.29	LPVOID ret_addr = VirtualAlloc(req_addr, req_size, alloc_type, PAGE_EXECUTE_READWRITE);
278	gbeauche	1.14	if (ret_addr != req_addr)
279			return -1;
280			#else
281	gbeauche	1.1	// Unsupported
282			return -1;
283			#endif
284			#endif
285	gbeauche	1.14	#endif
286	gbeauche	1.1
287			// Explicitely protect the newly mapped region here because on some systems,
288			// say MacOS X, mmap() doesn't honour the requested protection flags.
289	gbeauche	1.6	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
290	gbeauche	1.1	return -1;
291
292			return 0;
293			}
294
295			/* Deallocate any mapping for the region starting at ADDR and extending
296			LEN bytes. Returns 0 if successful, -1 on errors. */
297
298			int vm_release(void * addr, size_t size)
299			{
300	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
301			if (addr == VM_MAP_FAILED)
302			return 0;
303
304	gbeauche	1.1	#ifdef HAVE_MACH_VM
305	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
306			return -1;
307	gbeauche	1.1	#else
308			#ifdef HAVE_MMAP_VM
309	gbeauche	1.7	if (munmap((caddr_t)addr, size) != 0)
310	gbeauche	1.4	return -1;
311	gbeauche	1.1	#else
312	gbeauche	1.14	#ifdef HAVE_WIN32_VM
313			if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0)
314			return -1;
315			#else
316	gbeauche	1.1	free(addr);
317			#endif
318			#endif
319	gbeauche	1.14	#endif
320	gbeauche	1.4
321			return 0;
322	gbeauche	1.1	}
323
324			/* Change the memory protection of the region starting at ADDR and
325			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
326
327			int vm_protect(void * addr, size_t size, int prot)
328			{
329			#ifdef HAVE_MACH_VM
330			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
331			return ret_code == KERN_SUCCESS ? 0 : -1;
332			#else
333			#ifdef HAVE_MMAP_VM
334	gbeauche	1.7	int ret_code = mprotect((caddr_t)addr, size, prot);
335	gbeauche	1.1	return ret_code == 0 ? 0 : -1;
336			#else
337	gbeauche	1.14	#ifdef HAVE_WIN32_VM
338			DWORD old_prot;
339			int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot);
340			return ret_code != 0 ? 0 : -1;
341			#else
342	gbeauche	1.1	// Unsupported
343			return -1;
344			#endif
345			#endif
346	gbeauche	1.14	#endif
347	gbeauche	1.1	}
348
349	gbeauche	1.29	/* Return the addresses of the pages that got modified in the
350			specified range [ ADDR, ADDR + SIZE [ since the last reset of the watch
351			bits. Returns 0 if successful, -1 for errors. */
352
353			int vm_get_write_watch(void * addr, size_t size,
354			void ** pages, unsigned int * n_pages,
355			int options)
356			{
357			#ifdef HAVE_VM_WRITE_WATCH
358			#ifdef HAVE_WIN32_VM
359			DWORD flags = 0;
360			if (options & VM_WRITE_WATCH_RESET)
361			flags \|= WRITE_WATCH_FLAG_RESET;
362
363			ULONG page_size;
364			ULONG count = *n_pages;
365			int ret_code = GetWriteWatch(flags, addr, size, pages, &count, &page_size);
366			if (ret_code != 0)
367			return -1;
368
369			*n_pages = count;
370			return 0;
371			#endif
372			#endif
373			// Unsupported
374			return -1;
375			}
376
377			/* Reset the write-tracking state for the specified range [ ADDR, ADDR
378			+ SIZE [. Returns 0 if successful, -1 for errors. */
379
380			int vm_reset_write_watch(void * addr, size_t size)
381			{
382			#ifdef HAVE_VM_WRITE_WATCH
383			#ifdef HAVE_WIN32_VM
384			int ret_code = ResetWriteWatch(addr, size);
385			return ret_code == 0 ? 0 : -1;
386			#endif
387			#endif
388			// Unsupported
389			return -1;
390			}
391
392	gbeauche	1.15	/* Returns the size of a page. */
393
394	gbeauche	1.16	int vm_get_page_size(void)
395	gbeauche	1.15	{
396	gbeauche	1.20	#ifdef HAVE_WIN32_VM
397	gbeauche	1.28	static vm_uintptr_t page_size = 0;
398	gbeauche	1.20	if (page_size == 0) {
399			SYSTEM_INFO si;
400			GetSystemInfo(&si);
401			page_size = si.dwAllocationGranularity;
402			}
403			return page_size;
404	gbeauche	1.15	#else
405	gbeauche	1.20	return getpagesize();
406	gbeauche	1.15	#endif
407			}
408
409	gbeauche	1.29	#ifdef CONFIGURE_TEST_VM_WRITE_WATCH
410			int main(void)
411			{
412			int i, j;
413
414			vm_init();
415
416			vm_uintptr_t page_size = vm_get_page_size();
417
418			char *area;
419			const int n_pages = 7;
420			const int area_size = n_pages * page_size;
421			const int map_options = VM_MAP_DEFAULT \| VM_MAP_WRITE_WATCH;
422			if ((area = (char *)vm_acquire(area_size, map_options)) == VM_MAP_FAILED)
423			return 1;
424
425			unsigned int n_modified_pages_expected = 0;
426			static const int touch_page[n_pages] = { 0, 1, 1, 0, 1, 0, 1 };
427			for (i = 0; i < n_pages; i++) {
428			if (touch_page[i]) {
429			area[i * page_size] = 1;
430			++n_modified_pages_expected;
431			}
432			}
433
434			char *modified_pages[n_pages];
435			unsigned int n_modified_pages = n_pages;
436			if (vm_get_write_watch(area, area_size, (void **)modified_pages, &n_modified_pages) < 0)
437			return 2;
438			if (n_modified_pages != n_modified_pages_expected)
439			return 3;
440			for (i = 0, j = 0; i < n_pages; i++) {
441			char v = area[i * page_size];
442			if ((touch_page[i] && !v) \|\| (!touch_page[i] && v))
443			return 4;
444			if (!touch_page[i])
445			continue;
446			if (modified_pages[j] != (area + i * page_size))
447			return 5;
448			++j;
449			}
450
451			vm_release(area, area_size);
452			return 0;
453			}
454			#endif
455
456	gbeauche	1.1	#ifdef CONFIGURE_TEST_VM_MAP
457	gbeauche	1.18	#include <stdlib.h>
458			#include <signal.h>
459
460			static void fault_handler(int sig)
461			{
462			exit(1);
463			}
464
465	gbeauche	1.1	/* Tests covered here:
466			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
467			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
468			*/
469			int main(void)
470			{
471			vm_init();
472	gbeauche	1.18
473			signal(SIGSEGV, fault_handler);
474			#ifdef SIGBUS
475			signal(SIGBUS, fault_handler);
476			#endif
477	gbeauche	1.1
478	gbeauche	1.28	#define page_align(address) ((char *)((vm_uintptr_t)(address) & -page_size))
479			vm_uintptr_t page_size = vm_get_page_size();
480	gbeauche	1.1
481			const int area_size = 6 * page_size;
482			volatile char * area = (volatile char *) vm_acquire(area_size);
483			volatile char * fault_address = area + (page_size * 7) / 2;
484
485			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
486			if (area == VM_MAP_FAILED)
487			return 1;
488
489			if (vm_release((char *)area, area_size) < 0)
490			return 1;
491
492			return 0;
493			#endif
494
495			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
496			if (area == VM_MAP_FAILED)
497			return 0;
498
499			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
500			return 0;
501			#endif
502
503			#if defined(TEST_VM_PROT_RDWR_WRITE)
504			if (area == VM_MAP_FAILED)
505			return 1;
506
507			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
508			return 1;
509
510			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
511			return 1;
512			#endif
513
514			#if defined(TEST_VM_PROT_READ_WRITE)
515			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
516			return 0;
517			#endif
518
519			#if defined(TEST_VM_PROT_NONE_READ)
520			// this should cause a core dump
521			char foo = *fault_address;
522			return 0;
523			#endif
524
525			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
526			// this should cause a core dump
527			*fault_address = 'z';
528			return 0;
529			#endif
530
531			#if defined(TEST_VM_PROT_RDWR_WRITE)
532			// this should not cause a core dump
533			*fault_address = 'z';
534			return 0;
535			#endif
536			}
537			#endif