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"

#if defined(__APPLE__) && defined(__MACH__)
#include <sys/utsname.h>
#endif

#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

// On 10.4 and earlier, reset CrashReporter's task signal handler to
// avoid having it show up for signals that get handled.
#if defined(__APPLE__) && defined(__MACH__)
        struct utsname info;

        if (!uname(&info) && atoi(info.release) <= 8) {
                task_set_exception_ports(mach_task_self(),
                        EXC_MASK_BAD_ACCESS | EXC_MASK_ARITHMETIC,
                        MACH_PORT_NULL,
                        EXCEPTION_STATE_IDENTITY,
                        MACHINE_THREAD_STATE);
        }
#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

#if defined(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;
        }
#elif defined(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;
#elif defined(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

        // 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

#if defined(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;
        }
#elif defined(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;
#elif defined(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

        // 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:	1.35
Committed:	2012-01-01T22:32:24Z (12 years, 11 months ago) by asvitkine
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.34:	+5 -9 lines
Log Message:	cleanup ifdef chain syntax
#	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	asvitkine	1.33	#if defined(__APPLE__) && defined(__MACH__)
43			#include <sys/utsname.h>
44			#endif
45
46	gbeauche	1.1	#ifdef HAVE_MACH_VM
47			#ifndef HAVE_MACH_TASK_SELF
48			#ifdef HAVE_TASK_SELF
49			#define mach_task_self task_self
50			#else
51			#error "No task_self(), you lose."
52			#endif
53			#endif
54			#endif
55
56	gbeauche	1.28	#ifdef HAVE_WIN32_VM
57			/* Windows is either ILP32 or LLP64 */
58			typedef UINT_PTR vm_uintptr_t;
59			#else
60			/* Other systems are sane as they are either ILP32 or LP64 */
61			typedef unsigned long vm_uintptr_t;
62			#endif
63
64	gbeauche	1.9	/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII
65			because the emulated target is 32-bit and this helps to allocate
66			memory so that branches could be resolved more easily (32-bit
67			displacement to code in .text), on AMD64 for example. */
68	gbeauche	1.31	#if defined(__hpux)
69			#define MAP_32BIT MAP_ADDR32
70			#endif
71	gbeauche	1.9	#ifndef MAP_32BIT
72			#define MAP_32BIT 0
73			#endif
74	gbeauche	1.13	#ifndef MAP_ANON
75			#define MAP_ANON 0
76			#endif
77			#ifndef MAP_ANONYMOUS
78			#define MAP_ANONYMOUS 0
79			#endif
80	gbeauche	1.9
81			#define MAP_EXTRA_FLAGS (MAP_32BIT)
82
83	gbeauche	1.1	#ifdef HAVE_MMAP_VM
84	gbeauche	1.23	#if (defined(__linux__) && defined(__i386__)) \|\| HAVE_LINKER_SCRIPT
85	gbeauche	1.9	/* Force a reasonnable address below 0x80000000 on x86 so that we
86			don't get addresses above when the program is run on AMD64.
87			NOTE: this is empirically determined on Linux/x86. */
88			#define MAP_BASE 0x10000000
89			#else
90			#define MAP_BASE 0x00000000
91			#endif
92			static char * next_address = (char *)MAP_BASE;
93	gbeauche	1.1	#ifdef HAVE_MMAP_ANON
94	gbeauche	1.10	#define map_flags (MAP_ANON \| MAP_EXTRA_FLAGS)
95	gbeauche	1.1	#define zero_fd -1
96			#else
97			#ifdef HAVE_MMAP_ANONYMOUS
98	gbeauche	1.10	#define map_flags (MAP_ANONYMOUS \| MAP_EXTRA_FLAGS)
99	gbeauche	1.1	#define zero_fd -1
100			#else
101	gbeauche	1.10	#define map_flags (MAP_EXTRA_FLAGS)
102	gbeauche	1.1	static int zero_fd = -1;
103			#endif
104			#endif
105			#endif
106
107	gbeauche	1.10	/* Translate generic VM map flags to host values. */
108
109			#ifdef HAVE_MMAP_VM
110			static int translate_map_flags(int vm_flags)
111			{
112			int flags = 0;
113			if (vm_flags & VM_MAP_SHARED)
114			flags \|= MAP_SHARED;
115			if (vm_flags & VM_MAP_PRIVATE)
116			flags \|= MAP_PRIVATE;
117			if (vm_flags & VM_MAP_FIXED)
118			flags \|= MAP_FIXED;
119			if (vm_flags & VM_MAP_32BIT)
120			flags \|= MAP_32BIT;
121			return flags;
122			}
123			#endif
124
125	gbeauche	1.14	/* Align ADDR and SIZE to 64K boundaries. */
126
127			#ifdef HAVE_WIN32_VM
128			static inline LPVOID align_addr_segment(LPVOID addr)
129			{
130	gbeauche	1.28	return (LPVOID)(((vm_uintptr_t)addr) & -((vm_uintptr_t)65536));
131	gbeauche	1.14	}
132
133			static inline DWORD align_size_segment(LPVOID addr, DWORD size)
134			{
135	gbeauche	1.28	return size + ((vm_uintptr_t)addr - (vm_uintptr_t)align_addr_segment(addr));
136	gbeauche	1.14	}
137			#endif
138
139			/* Translate generic VM prot flags to host values. */
140
141			#ifdef HAVE_WIN32_VM
142			static int translate_prot_flags(int prot_flags)
143			{
144			int prot = PAGE_READWRITE;
145			if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ \| VM_PAGE_WRITE))
146			prot = PAGE_EXECUTE_READWRITE;
147			else if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ))
148			prot = PAGE_EXECUTE_READ;
149			else if (prot_flags == (VM_PAGE_READ \| VM_PAGE_WRITE))
150			prot = PAGE_READWRITE;
151			else if (prot_flags == VM_PAGE_READ)
152			prot = PAGE_READONLY;
153			else if (prot_flags == 0)
154			prot = PAGE_NOACCESS;
155			return prot;
156			}
157			#endif
158
159	asvitkine	1.32	/* Translate Mach return codes to POSIX errno values. */
160			#ifdef HAVE_MACH_VM
161			static int vm_error(kern_return_t ret_code)
162			{
163			switch (ret_code) {
164			case KERN_SUCCESS:
165			return 0;
166			case KERN_INVALID_ADDRESS:
167			case KERN_NO_SPACE:
168			return ENOMEM;
169			case KERN_PROTECTION_FAILURE:
170			return EACCES;
171			default:
172			return EINVAL;
173			}
174			}
175			#endif
176
177	gbeauche	1.1	/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
178
179			int vm_init(void)
180			{
181			#ifdef HAVE_MMAP_VM
182			#ifndef zero_fd
183			zero_fd = open("/dev/zero", O_RDWR);
184			if (zero_fd < 0)
185			return -1;
186			#endif
187			#endif
188	asvitkine	1.33
189			// On 10.4 and earlier, reset CrashReporter's task signal handler to
190			// avoid having it show up for signals that get handled.
191			#if defined(__APPLE__) && defined(__MACH__)
192			struct utsname info;
193
194			if (!uname(&info) && atoi(info.release) <= 8) {
195			task_set_exception_ports(mach_task_self(),
196			EXC_MASK_BAD_ACCESS \| EXC_MASK_ARITHMETIC,
197			MACH_PORT_NULL,
198			EXCEPTION_STATE_IDENTITY,
199			MACHINE_THREAD_STATE);
200			}
201			#endif
202
203	gbeauche	1.1	return 0;
204			}
205
206			/* Deallocate all internal data used to wrap virtual memory allocators. */
207
208			void vm_exit(void)
209			{
210			#ifdef HAVE_MMAP_VM
211			#ifndef zero_fd
212	gbeauche	1.19	if (zero_fd != -1) {
213			close(zero_fd);
214			zero_fd = -1;
215			}
216	gbeauche	1.1	#endif
217			#endif
218			}
219
220			/* Allocate zero-filled memory of SIZE bytes. The mapping is private
221			and default protection bits are read / write. The return value
222			is the actual mapping address chosen or VM_MAP_FAILED for errors. */
223
224	gbeauche	1.10	void * vm_acquire(size_t size, int options)
225	gbeauche	1.1	{
226			void * addr;
227	asvitkine	1.32
228			errno = 0;
229	gbeauche	1.10
230			// VM_MAP_FIXED are to be used with vm_acquire_fixed() only
231			if (options & VM_MAP_FIXED)
232			return VM_MAP_FAILED;
233
234	gbeauche	1.29	#ifndef HAVE_VM_WRITE_WATCH
235			if (options & VM_MAP_WRITE_WATCH)
236			return VM_MAP_FAILED;
237			#endif
238
239	asvitkine	1.34	#if defined(HAVE_MACH_VM)
240	gbeauche	1.1	// vm_allocate() returns a zero-filled memory region
241	asvitkine	1.32	kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE);
242			if (ret_code != KERN_SUCCESS) {
243			errno = vm_error(ret_code);
244	gbeauche	1.1	return VM_MAP_FAILED;
245	asvitkine	1.32	}
246	asvitkine	1.34	#elif defined(HAVE_MMAP_VM)
247	gbeauche	1.13	int fd = zero_fd;
248			int the_map_flags = translate_map_flags(options) \| map_flags;
249
250			if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED)
251	gbeauche	1.1	return VM_MAP_FAILED;
252
253	gbeauche	1.10	// Sanity checks for 64-bit platforms
254			if (sizeof(void ) == 8 && (options & VM_MAP_32BIT) && !((char )addr <= (char *)0xffffffff))
255			return VM_MAP_FAILED;
256
257	gbeauche	1.3	next_address = (char *)addr + size;
258	asvitkine	1.34	#elif defined(HAVE_WIN32_VM)
259	gbeauche	1.29	int alloc_type = MEM_RESERVE \| MEM_COMMIT;
260			if (options & VM_MAP_WRITE_WATCH)
261			alloc_type \|= MEM_WRITE_WATCH;
262
263			if ((addr = VirtualAlloc(NULL, size, alloc_type, PAGE_EXECUTE_READWRITE)) == NULL)
264	gbeauche	1.14	return VM_MAP_FAILED;
265			#else
266	gbeauche	1.1	if ((addr = calloc(size, 1)) == 0)
267			return VM_MAP_FAILED;
268
269			// Omit changes for protections because they are not supported in this mode
270			return addr;
271			#endif
272	cebix	1.2
273	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
274			// say MacOS X, mmap() doesn't honour the requested protection flags.
275			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
276			return VM_MAP_FAILED;
277
278			return addr;
279			}
280
281			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
282			Retuns 0 if successful, -1 on errors. */
283
284	gbeauche	1.10	int vm_acquire_fixed(void * addr, size_t size, int options)
285	gbeauche	1.1	{
286	asvitkine	1.32	errno = 0;
287
288	gbeauche	1.10	// Fixed mappings are required to be private
289			if (options & VM_MAP_SHARED)
290			return -1;
291
292	gbeauche	1.29	#ifndef HAVE_VM_WRITE_WATCH
293			if (options & VM_MAP_WRITE_WATCH)
294			return -1;
295			#endif
296
297	asvitkine	1.35	#if defined(HAVE_MACH_VM)
298	gbeauche	1.1	// vm_allocate() returns a zero-filled memory region
299	asvitkine	1.32	kern_return_t ret_code = vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0);
300			if (ret_code != KERN_SUCCESS) {
301			errno = vm_error(ret_code);
302	gbeauche	1.1	return -1;
303	asvitkine	1.32	}
304	asvitkine	1.35	#elif defined(HAVE_MMAP_VM)
305	gbeauche	1.21	int fd = zero_fd;
306			int the_map_flags = translate_map_flags(options) \| map_flags \| MAP_FIXED;
307	gbeauche	1.10
308	gbeauche	1.21	if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED)
309	gbeauche	1.1	return -1;
310	asvitkine	1.35	#elif defined(HAVE_WIN32_VM)
311	gbeauche	1.14	// Windows cannot allocate Low Memory
312			if (addr == NULL)
313			return -1;
314
315	gbeauche	1.29	int alloc_type = MEM_RESERVE \| MEM_COMMIT;
316			if (options & VM_MAP_WRITE_WATCH)
317			alloc_type \|= MEM_WRITE_WATCH;
318
319	gbeauche	1.14	// Allocate a possibly offset region to align on 64K boundaries
320			LPVOID req_addr = align_addr_segment(addr);
321			DWORD req_size = align_size_segment(addr, size);
322	gbeauche	1.29	LPVOID ret_addr = VirtualAlloc(req_addr, req_size, alloc_type, PAGE_EXECUTE_READWRITE);
323	gbeauche	1.14	if (ret_addr != req_addr)
324			return -1;
325			#else
326	gbeauche	1.1	// Unsupported
327			return -1;
328			#endif
329	asvitkine	1.35
330	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
331			// say MacOS X, mmap() doesn't honour the requested protection flags.
332	gbeauche	1.6	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
333	gbeauche	1.1	return -1;
334	asvitkine	1.35
335	gbeauche	1.1	return 0;
336			}
337
338			/* Deallocate any mapping for the region starting at ADDR and extending
339			LEN bytes. Returns 0 if successful, -1 on errors. */
340
341			int vm_release(void * addr, size_t size)
342			{
343	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
344			if (addr == VM_MAP_FAILED)
345			return 0;
346
347	gbeauche	1.1	#ifdef HAVE_MACH_VM
348	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
349			return -1;
350	gbeauche	1.1	#else
351			#ifdef HAVE_MMAP_VM
352	gbeauche	1.7	if (munmap((caddr_t)addr, size) != 0)
353	gbeauche	1.4	return -1;
354	gbeauche	1.1	#else
355	gbeauche	1.14	#ifdef HAVE_WIN32_VM
356			if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0)
357			return -1;
358			#else
359	gbeauche	1.1	free(addr);
360			#endif
361			#endif
362	gbeauche	1.14	#endif
363	gbeauche	1.4
364			return 0;
365	gbeauche	1.1	}
366
367			/* Change the memory protection of the region starting at ADDR and
368			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
369
370			int vm_protect(void * addr, size_t size, int prot)
371			{
372			#ifdef HAVE_MACH_VM
373			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
374			return ret_code == KERN_SUCCESS ? 0 : -1;
375			#else
376			#ifdef HAVE_MMAP_VM
377	gbeauche	1.7	int ret_code = mprotect((caddr_t)addr, size, prot);
378	gbeauche	1.1	return ret_code == 0 ? 0 : -1;
379			#else
380	gbeauche	1.14	#ifdef HAVE_WIN32_VM
381			DWORD old_prot;
382			int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot);
383			return ret_code != 0 ? 0 : -1;
384			#else
385	gbeauche	1.1	// Unsupported
386			return -1;
387			#endif
388			#endif
389	gbeauche	1.14	#endif
390	gbeauche	1.1	}
391
392	gbeauche	1.29	/* Return the addresses of the pages that got modified in the
393			specified range [ ADDR, ADDR + SIZE [ since the last reset of the watch
394			bits. Returns 0 if successful, -1 for errors. */
395
396			int vm_get_write_watch(void * addr, size_t size,
397			void ** pages, unsigned int * n_pages,
398			int options)
399			{
400			#ifdef HAVE_VM_WRITE_WATCH
401			#ifdef HAVE_WIN32_VM
402			DWORD flags = 0;
403			if (options & VM_WRITE_WATCH_RESET)
404			flags \|= WRITE_WATCH_FLAG_RESET;
405
406			ULONG page_size;
407	gbeauche	1.30	ULONG_PTR count = *n_pages;
408	gbeauche	1.29	int ret_code = GetWriteWatch(flags, addr, size, pages, &count, &page_size);
409			if (ret_code != 0)
410			return -1;
411
412			*n_pages = count;
413			return 0;
414			#endif
415			#endif
416			// Unsupported
417			return -1;
418			}
419
420			/* Reset the write-tracking state for the specified range [ ADDR, ADDR
421			+ SIZE [. Returns 0 if successful, -1 for errors. */
422
423			int vm_reset_write_watch(void * addr, size_t size)
424			{
425			#ifdef HAVE_VM_WRITE_WATCH
426			#ifdef HAVE_WIN32_VM
427			int ret_code = ResetWriteWatch(addr, size);
428			return ret_code == 0 ? 0 : -1;
429			#endif
430			#endif
431			// Unsupported
432			return -1;
433			}
434
435	gbeauche	1.15	/* Returns the size of a page. */
436
437	gbeauche	1.16	int vm_get_page_size(void)
438	gbeauche	1.15	{
439	gbeauche	1.20	#ifdef HAVE_WIN32_VM
440	gbeauche	1.28	static vm_uintptr_t page_size = 0;
441	gbeauche	1.20	if (page_size == 0) {
442			SYSTEM_INFO si;
443			GetSystemInfo(&si);
444			page_size = si.dwAllocationGranularity;
445			}
446			return page_size;
447	gbeauche	1.15	#else
448	gbeauche	1.20	return getpagesize();
449	gbeauche	1.15	#endif
450			}
451
452	gbeauche	1.29	#ifdef CONFIGURE_TEST_VM_WRITE_WATCH
453			int main(void)
454			{
455			int i, j;
456
457			vm_init();
458
459			vm_uintptr_t page_size = vm_get_page_size();
460
461			char *area;
462			const int n_pages = 7;
463			const int area_size = n_pages * page_size;
464			const int map_options = VM_MAP_DEFAULT \| VM_MAP_WRITE_WATCH;
465			if ((area = (char *)vm_acquire(area_size, map_options)) == VM_MAP_FAILED)
466			return 1;
467
468			unsigned int n_modified_pages_expected = 0;
469			static const int touch_page[n_pages] = { 0, 1, 1, 0, 1, 0, 1 };
470			for (i = 0; i < n_pages; i++) {
471			if (touch_page[i]) {
472			area[i * page_size] = 1;
473			++n_modified_pages_expected;
474			}
475			}
476
477			char *modified_pages[n_pages];
478			unsigned int n_modified_pages = n_pages;
479			if (vm_get_write_watch(area, area_size, (void **)modified_pages, &n_modified_pages) < 0)
480			return 2;
481			if (n_modified_pages != n_modified_pages_expected)
482			return 3;
483			for (i = 0, j = 0; i < n_pages; i++) {
484			char v = area[i * page_size];
485			if ((touch_page[i] && !v) \|\| (!touch_page[i] && v))
486			return 4;
487			if (!touch_page[i])
488			continue;
489			if (modified_pages[j] != (area + i * page_size))
490			return 5;
491			++j;
492			}
493
494			vm_release(area, area_size);
495			return 0;
496			}
497			#endif
498
499	gbeauche	1.1	#ifdef CONFIGURE_TEST_VM_MAP
500	gbeauche	1.18	#include <stdlib.h>
501			#include <signal.h>
502
503			static void fault_handler(int sig)
504			{
505			exit(1);
506			}
507
508	gbeauche	1.1	/* Tests covered here:
509			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
510			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
511			*/
512			int main(void)
513			{
514			vm_init();
515	gbeauche	1.18
516			signal(SIGSEGV, fault_handler);
517			#ifdef SIGBUS
518			signal(SIGBUS, fault_handler);
519			#endif
520	gbeauche	1.1
521	gbeauche	1.28	#define page_align(address) ((char *)((vm_uintptr_t)(address) & -page_size))
522			vm_uintptr_t page_size = vm_get_page_size();
523	gbeauche	1.1
524			const int area_size = 6 * page_size;
525			volatile char * area = (volatile char *) vm_acquire(area_size);
526			volatile char * fault_address = area + (page_size * 7) / 2;
527
528			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
529			if (area == VM_MAP_FAILED)
530			return 1;
531
532			if (vm_release((char *)area, area_size) < 0)
533			return 1;
534
535			return 0;
536			#endif
537
538			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
539			if (area == VM_MAP_FAILED)
540			return 0;
541
542			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
543			return 0;
544			#endif
545
546			#if defined(TEST_VM_PROT_RDWR_WRITE)
547			if (area == VM_MAP_FAILED)
548			return 1;
549
550			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
551			return 1;
552
553			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
554			return 1;
555			#endif
556
557			#if defined(TEST_VM_PROT_READ_WRITE)
558			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
559			return 0;
560			#endif
561
562			#if defined(TEST_VM_PROT_NONE_READ)
563			// this should cause a core dump
564			char foo = *fault_address;
565			return 0;
566			#endif
567
568			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
569			// this should cause a core dump
570			*fault_address = 'z';
571			return 0;
572			#endif
573
574			#if defined(TEST_VM_PROT_RDWR_WRITE)
575			// this should not cause a core dump
576			*fault_address = 'z';
577			return 0;
578			#endif
579			}
580			#endif