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.  */
#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

/* 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_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:	1.31
Committed:	2008-01-20T00:38:52Z (16 years, 7 months ago) by gbeauche
Branch:	MAIN
Changes since 1.30:	+3 -0 lines
Log Message:	HP-UX does support 32-bit memory mappings.
#	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	gbeauche	1.31	#if defined(__hpux)
64			#define MAP_32BIT MAP_ADDR32
65			#endif
66	gbeauche	1.9	#ifndef MAP_32BIT
67			#define MAP_32BIT 0
68			#endif
69	gbeauche	1.13	#ifndef MAP_ANON
70			#define MAP_ANON 0
71			#endif
72			#ifndef MAP_ANONYMOUS
73			#define MAP_ANONYMOUS 0
74			#endif
75	gbeauche	1.9
76			#define MAP_EXTRA_FLAGS (MAP_32BIT)
77
78	gbeauche	1.1	#ifdef HAVE_MMAP_VM
79	gbeauche	1.23	#if (defined(__linux__) && defined(__i386__)) \|\| HAVE_LINKER_SCRIPT
80	gbeauche	1.9	/* Force a reasonnable address below 0x80000000 on x86 so that we
81			don't get addresses above when the program is run on AMD64.
82			NOTE: this is empirically determined on Linux/x86. */
83			#define MAP_BASE 0x10000000
84			#else
85			#define MAP_BASE 0x00000000
86			#endif
87			static char * next_address = (char *)MAP_BASE;
88	gbeauche	1.1	#ifdef HAVE_MMAP_ANON
89	gbeauche	1.10	#define map_flags (MAP_ANON \| MAP_EXTRA_FLAGS)
90	gbeauche	1.1	#define zero_fd -1
91			#else
92			#ifdef HAVE_MMAP_ANONYMOUS
93	gbeauche	1.10	#define map_flags (MAP_ANONYMOUS \| MAP_EXTRA_FLAGS)
94	gbeauche	1.1	#define zero_fd -1
95			#else
96	gbeauche	1.10	#define map_flags (MAP_EXTRA_FLAGS)
97	gbeauche	1.1	static int zero_fd = -1;
98			#endif
99			#endif
100			#endif
101
102	gbeauche	1.10	/* Translate generic VM map flags to host values. */
103
104			#ifdef HAVE_MMAP_VM
105			static int translate_map_flags(int vm_flags)
106			{
107			int flags = 0;
108			if (vm_flags & VM_MAP_SHARED)
109			flags \|= MAP_SHARED;
110			if (vm_flags & VM_MAP_PRIVATE)
111			flags \|= MAP_PRIVATE;
112			if (vm_flags & VM_MAP_FIXED)
113			flags \|= MAP_FIXED;
114			if (vm_flags & VM_MAP_32BIT)
115			flags \|= MAP_32BIT;
116			return flags;
117			}
118			#endif
119
120	gbeauche	1.14	/* Align ADDR and SIZE to 64K boundaries. */
121
122			#ifdef HAVE_WIN32_VM
123			static inline LPVOID align_addr_segment(LPVOID addr)
124			{
125	gbeauche	1.28	return (LPVOID)(((vm_uintptr_t)addr) & -((vm_uintptr_t)65536));
126	gbeauche	1.14	}
127
128			static inline DWORD align_size_segment(LPVOID addr, DWORD size)
129			{
130	gbeauche	1.28	return size + ((vm_uintptr_t)addr - (vm_uintptr_t)align_addr_segment(addr));
131	gbeauche	1.14	}
132			#endif
133
134			/* Translate generic VM prot flags to host values. */
135
136			#ifdef HAVE_WIN32_VM
137			static int translate_prot_flags(int prot_flags)
138			{
139			int prot = PAGE_READWRITE;
140			if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ \| VM_PAGE_WRITE))
141			prot = PAGE_EXECUTE_READWRITE;
142			else if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ))
143			prot = PAGE_EXECUTE_READ;
144			else if (prot_flags == (VM_PAGE_READ \| VM_PAGE_WRITE))
145			prot = PAGE_READWRITE;
146			else if (prot_flags == VM_PAGE_READ)
147			prot = PAGE_READONLY;
148			else if (prot_flags == 0)
149			prot = PAGE_NOACCESS;
150			return prot;
151			}
152			#endif
153
154	gbeauche	1.1	/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
155
156			int vm_init(void)
157			{
158			#ifdef HAVE_MMAP_VM
159			#ifndef zero_fd
160			zero_fd = open("/dev/zero", O_RDWR);
161			if (zero_fd < 0)
162			return -1;
163			#endif
164			#endif
165			return 0;
166			}
167
168			/* Deallocate all internal data used to wrap virtual memory allocators. */
169
170			void vm_exit(void)
171			{
172			#ifdef HAVE_MMAP_VM
173			#ifndef zero_fd
174	gbeauche	1.19	if (zero_fd != -1) {
175			close(zero_fd);
176			zero_fd = -1;
177			}
178	gbeauche	1.1	#endif
179			#endif
180			}
181
182			/* Allocate zero-filled memory of SIZE bytes. The mapping is private
183			and default protection bits are read / write. The return value
184			is the actual mapping address chosen or VM_MAP_FAILED for errors. */
185
186	gbeauche	1.10	void * vm_acquire(size_t size, int options)
187	gbeauche	1.1	{
188			void * addr;
189	gbeauche	1.10
190			// VM_MAP_FIXED are to be used with vm_acquire_fixed() only
191			if (options & VM_MAP_FIXED)
192			return VM_MAP_FAILED;
193
194	gbeauche	1.29	#ifndef HAVE_VM_WRITE_WATCH
195			if (options & VM_MAP_WRITE_WATCH)
196			return VM_MAP_FAILED;
197			#endif
198
199	gbeauche	1.1	#ifdef HAVE_MACH_VM
200			// vm_allocate() returns a zero-filled memory region
201			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
202			return VM_MAP_FAILED;
203			#else
204			#ifdef HAVE_MMAP_VM
205	gbeauche	1.13	int fd = zero_fd;
206			int the_map_flags = translate_map_flags(options) \| map_flags;
207
208			if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED)
209	gbeauche	1.1	return VM_MAP_FAILED;
210
211	gbeauche	1.10	// Sanity checks for 64-bit platforms
212			if (sizeof(void ) == 8 && (options & VM_MAP_32BIT) && !((char )addr <= (char *)0xffffffff))
213			return VM_MAP_FAILED;
214
215	gbeauche	1.3	next_address = (char *)addr + size;
216	gbeauche	1.1	#else
217	gbeauche	1.14	#ifdef HAVE_WIN32_VM
218	gbeauche	1.29	int alloc_type = MEM_RESERVE \| MEM_COMMIT;
219			if (options & VM_MAP_WRITE_WATCH)
220			alloc_type \|= MEM_WRITE_WATCH;
221
222			if ((addr = VirtualAlloc(NULL, size, alloc_type, PAGE_EXECUTE_READWRITE)) == NULL)
223	gbeauche	1.14	return VM_MAP_FAILED;
224			#else
225	gbeauche	1.1	if ((addr = calloc(size, 1)) == 0)
226			return VM_MAP_FAILED;
227
228			// Omit changes for protections because they are not supported in this mode
229			return addr;
230			#endif
231			#endif
232	gbeauche	1.14	#endif
233	cebix	1.2
234	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
235			// say MacOS X, mmap() doesn't honour the requested protection flags.
236			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
237			return VM_MAP_FAILED;
238
239			return addr;
240			}
241
242			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
243			Retuns 0 if successful, -1 on errors. */
244
245	gbeauche	1.10	int vm_acquire_fixed(void * addr, size_t size, int options)
246	gbeauche	1.1	{
247	gbeauche	1.10	// Fixed mappings are required to be private
248			if (options & VM_MAP_SHARED)
249			return -1;
250
251	gbeauche	1.29	#ifndef HAVE_VM_WRITE_WATCH
252			if (options & VM_MAP_WRITE_WATCH)
253			return -1;
254			#endif
255
256	gbeauche	1.1	#ifdef HAVE_MACH_VM
257			// vm_allocate() returns a zero-filled memory region
258			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
259			return -1;
260			#else
261			#ifdef HAVE_MMAP_VM
262	gbeauche	1.21	int fd = zero_fd;
263			int the_map_flags = translate_map_flags(options) \| map_flags \| MAP_FIXED;
264	gbeauche	1.10
265	gbeauche	1.21	if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED)
266	gbeauche	1.1	return -1;
267			#else
268	gbeauche	1.14	#ifdef HAVE_WIN32_VM
269			// Windows cannot allocate Low Memory
270			if (addr == NULL)
271			return -1;
272
273	gbeauche	1.29	int alloc_type = MEM_RESERVE \| MEM_COMMIT;
274			if (options & VM_MAP_WRITE_WATCH)
275			alloc_type \|= MEM_WRITE_WATCH;
276
277	gbeauche	1.14	// Allocate a possibly offset region to align on 64K boundaries
278			LPVOID req_addr = align_addr_segment(addr);
279			DWORD req_size = align_size_segment(addr, size);
280	gbeauche	1.29	LPVOID ret_addr = VirtualAlloc(req_addr, req_size, alloc_type, PAGE_EXECUTE_READWRITE);
281	gbeauche	1.14	if (ret_addr != req_addr)
282			return -1;
283			#else
284	gbeauche	1.1	// Unsupported
285			return -1;
286			#endif
287			#endif
288	gbeauche	1.14	#endif
289	gbeauche	1.1
290			// Explicitely protect the newly mapped region here because on some systems,
291			// say MacOS X, mmap() doesn't honour the requested protection flags.
292	gbeauche	1.6	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
293	gbeauche	1.1	return -1;
294
295			return 0;
296			}
297
298			/* Deallocate any mapping for the region starting at ADDR and extending
299			LEN bytes. Returns 0 if successful, -1 on errors. */
300
301			int vm_release(void * addr, size_t size)
302			{
303	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
304			if (addr == VM_MAP_FAILED)
305			return 0;
306
307	gbeauche	1.1	#ifdef HAVE_MACH_VM
308	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
309			return -1;
310	gbeauche	1.1	#else
311			#ifdef HAVE_MMAP_VM
312	gbeauche	1.7	if (munmap((caddr_t)addr, size) != 0)
313	gbeauche	1.4	return -1;
314	gbeauche	1.1	#else
315	gbeauche	1.14	#ifdef HAVE_WIN32_VM
316			if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0)
317			return -1;
318			#else
319	gbeauche	1.1	free(addr);
320			#endif
321			#endif
322	gbeauche	1.14	#endif
323	gbeauche	1.4
324			return 0;
325	gbeauche	1.1	}
326
327			/* Change the memory protection of the region starting at ADDR and
328			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
329
330			int vm_protect(void * addr, size_t size, int prot)
331			{
332			#ifdef HAVE_MACH_VM
333			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
334			return ret_code == KERN_SUCCESS ? 0 : -1;
335			#else
336			#ifdef HAVE_MMAP_VM
337	gbeauche	1.7	int ret_code = mprotect((caddr_t)addr, size, prot);
338	gbeauche	1.1	return ret_code == 0 ? 0 : -1;
339			#else
340	gbeauche	1.14	#ifdef HAVE_WIN32_VM
341			DWORD old_prot;
342			int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot);
343			return ret_code != 0 ? 0 : -1;
344			#else
345	gbeauche	1.1	// Unsupported
346			return -1;
347			#endif
348			#endif
349	gbeauche	1.14	#endif
350	gbeauche	1.1	}
351
352	gbeauche	1.29	/* Return the addresses of the pages that got modified in the
353			specified range [ ADDR, ADDR + SIZE [ since the last reset of the watch
354			bits. Returns 0 if successful, -1 for errors. */
355
356			int vm_get_write_watch(void * addr, size_t size,
357			void ** pages, unsigned int * n_pages,
358			int options)
359			{
360			#ifdef HAVE_VM_WRITE_WATCH
361			#ifdef HAVE_WIN32_VM
362			DWORD flags = 0;
363			if (options & VM_WRITE_WATCH_RESET)
364			flags \|= WRITE_WATCH_FLAG_RESET;
365
366			ULONG page_size;
367	gbeauche	1.30	ULONG_PTR count = *n_pages;
368	gbeauche	1.29	int ret_code = GetWriteWatch(flags, addr, size, pages, &count, &page_size);
369			if (ret_code != 0)
370			return -1;
371
372			*n_pages = count;
373			return 0;
374			#endif
375			#endif
376			// Unsupported
377			return -1;
378			}
379
380			/* Reset the write-tracking state for the specified range [ ADDR, ADDR
381			+ SIZE [. Returns 0 if successful, -1 for errors. */
382
383			int vm_reset_write_watch(void * addr, size_t size)
384			{
385			#ifdef HAVE_VM_WRITE_WATCH
386			#ifdef HAVE_WIN32_VM
387			int ret_code = ResetWriteWatch(addr, size);
388			return ret_code == 0 ? 0 : -1;
389			#endif
390			#endif
391			// Unsupported
392			return -1;
393			}
394
395	gbeauche	1.15	/* Returns the size of a page. */
396
397	gbeauche	1.16	int vm_get_page_size(void)
398	gbeauche	1.15	{
399	gbeauche	1.20	#ifdef HAVE_WIN32_VM
400	gbeauche	1.28	static vm_uintptr_t page_size = 0;
401	gbeauche	1.20	if (page_size == 0) {
402			SYSTEM_INFO si;
403			GetSystemInfo(&si);
404			page_size = si.dwAllocationGranularity;
405			}
406			return page_size;
407	gbeauche	1.15	#else
408	gbeauche	1.20	return getpagesize();
409	gbeauche	1.15	#endif
410			}
411
412	gbeauche	1.29	#ifdef CONFIGURE_TEST_VM_WRITE_WATCH
413			int main(void)
414			{
415			int i, j;
416
417			vm_init();
418
419			vm_uintptr_t page_size = vm_get_page_size();
420
421			char *area;
422			const int n_pages = 7;
423			const int area_size = n_pages * page_size;
424			const int map_options = VM_MAP_DEFAULT \| VM_MAP_WRITE_WATCH;
425			if ((area = (char *)vm_acquire(area_size, map_options)) == VM_MAP_FAILED)
426			return 1;
427
428			unsigned int n_modified_pages_expected = 0;
429			static const int touch_page[n_pages] = { 0, 1, 1, 0, 1, 0, 1 };
430			for (i = 0; i < n_pages; i++) {
431			if (touch_page[i]) {
432			area[i * page_size] = 1;
433			++n_modified_pages_expected;
434			}
435			}
436
437			char *modified_pages[n_pages];
438			unsigned int n_modified_pages = n_pages;
439			if (vm_get_write_watch(area, area_size, (void **)modified_pages, &n_modified_pages) < 0)
440			return 2;
441			if (n_modified_pages != n_modified_pages_expected)
442			return 3;
443			for (i = 0, j = 0; i < n_pages; i++) {
444			char v = area[i * page_size];
445			if ((touch_page[i] && !v) \|\| (!touch_page[i] && v))
446			return 4;
447			if (!touch_page[i])
448			continue;
449			if (modified_pages[j] != (area + i * page_size))
450			return 5;
451			++j;
452			}
453
454			vm_release(area, area_size);
455			return 0;
456			}
457			#endif
458
459	gbeauche	1.1	#ifdef CONFIGURE_TEST_VM_MAP
460	gbeauche	1.18	#include <stdlib.h>
461			#include <signal.h>
462
463			static void fault_handler(int sig)
464			{
465			exit(1);
466			}
467
468	gbeauche	1.1	/* Tests covered here:
469			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
470			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
471			*/
472			int main(void)
473			{
474			vm_init();
475	gbeauche	1.18
476			signal(SIGSEGV, fault_handler);
477			#ifdef SIGBUS
478			signal(SIGBUS, fault_handler);
479			#endif
480	gbeauche	1.1
481	gbeauche	1.28	#define page_align(address) ((char *)((vm_uintptr_t)(address) & -page_size))
482			vm_uintptr_t page_size = vm_get_page_size();
483	gbeauche	1.1
484			const int area_size = 6 * page_size;
485			volatile char * area = (volatile char *) vm_acquire(area_size);
486			volatile char * fault_address = area + (page_size * 7) / 2;
487
488			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
489			if (area == VM_MAP_FAILED)
490			return 1;
491
492			if (vm_release((char *)area, area_size) < 0)
493			return 1;
494
495			return 0;
496			#endif
497
498			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
499			if (area == VM_MAP_FAILED)
500			return 0;
501
502			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
503			return 0;
504			#endif
505
506			#if defined(TEST_VM_PROT_RDWR_WRITE)
507			if (area == VM_MAP_FAILED)
508			return 1;
509
510			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
511			return 1;
512
513			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
514			return 1;
515			#endif
516
517			#if defined(TEST_VM_PROT_READ_WRITE)
518			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
519			return 0;
520			#endif
521
522			#if defined(TEST_VM_PROT_NONE_READ)
523			// this should cause a core dump
524			char foo = *fault_address;
525			return 0;
526			#endif
527
528			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
529			// this should cause a core dump
530			*fault_address = 'z';
531			return 0;
532			#endif
533
534			#if defined(TEST_VM_PROT_RDWR_WRITE)
535			// this should not cause a core dump
536			*fault_address = 'z';
537			return 0;
538			#endif
539			}
540			#endif