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) 1997-2005 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

/* 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__)
/* 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

/* Utility functions for POSIX SHM handling.  */

#ifdef USE_33BIT_ADDRESSING
struct shm_range_t {
        const char *file;
        void *base;
        unsigned int size;
        shm_range_t *next;
};

static shm_range_t *shm_ranges = NULL;

static bool add_shm_range(const char *file, void *base, unsigned int size)
{
        shm_range_t *r = (shm_range_t *)malloc(sizeof(shm_range_t));
        if (r) {
                r->file = file;
                r->base = base;
                r->size = size;
                r->next = shm_ranges ? shm_ranges : NULL;
                shm_ranges = r;
                return true;
        }
        return false;
}

static shm_range_t *find_shm_range(void *base, unsigned int size)
{
        for (shm_range_t *r = shm_ranges; r != NULL; r = r->next)
                if (r->base == base && r->size == size)
                        return r;
        return NULL;
}

static bool remove_shm_range(shm_range_t *r)
{
        if (r) {
                for (shm_range_t *p = shm_ranges; p != NULL; p = p->next) {
                        if (p->next == r) {
                                p->next = r->next;
                                free(r);
                                return true;
                        }
                }
        }
        return false;
}

static bool remove_shm_range(void *base, unsigned int size)
{
        remove_shm_range(find_shm_range(base, size));
}
#endif

/* Build a POSIX SHM memory segment file descriptor name.  */

#ifdef USE_33BIT_ADDRESSING
static const char *build_shm_filename(void)
{
        static int id = 0;
        static char filename[PATH_MAX];
        
        int ret = snprintf(filename, sizeof(filename), "/BasiliskII-%d-shm-%d", getpid(), id);
        if (ret == -1 || ret >= sizeof(filename))
                return NULL;

        id++;
        return filename;
}
#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)(((DWORD)addr) & -65536);
}

static inline DWORD align_size_segment(LPVOID addr, DWORD size)
{
        return size + ((DWORD)addr - (DWORD)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;

#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;

#ifdef USE_33BIT_ADDRESSING
        const char *shm_file = NULL;
        if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
                the_map_flags &= ~(MAP_PRIVATE | MAP_ANON | MAP_ANONYMOUS);
                the_map_flags |= MAP_SHARED;

                if ((shm_file = build_shm_filename()) == NULL)
                        return VM_MAP_FAILED;

                if ((fd = shm_open(shm_file, O_RDWR | O_CREAT | O_EXCL, 0644)) < 0)
                        return VM_MAP_FAILED;

                if (ftruncate(fd, size) < 0)
                        return VM_MAP_FAILED;
        }
#endif

        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;

        // Remap to 33-bit space
#ifdef USE_33BIT_ADDRESSING
        if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
                if (!add_shm_range(strdup(shm_file), addr, size))
                        return VM_MAP_FAILED;

                if (mmap((char *)addr + (1L << 32), size, VM_PAGE_DEFAULT, the_map_flags | MAP_FIXED, fd, 0) == (void *)MAP_FAILED)
                        return VM_MAP_FAILED;
                close(fd);
        }
#endif
#else
#ifdef HAVE_WIN32_VM
        if ((addr = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT, 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;

#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;

#ifdef USE_33BIT_ADDRESSING
        const char *shm_file = NULL;
        if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
                the_map_flags &= ~(MAP_PRIVATE | MAP_ANON | MAP_ANONYMOUS);
                the_map_flags |= MAP_SHARED;

                if ((shm_file = build_shm_filename()) == NULL)
                        return -1;

                if ((fd = shm_open(shm_file, O_RDWR | O_CREAT | O_EXCL, 0644)) < 0)
                        return -1;

                if (ftruncate(fd, size) < 0)
                        return -1;
        }
#endif

        if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED)
                return -1;

        // Remap to 33-bit space
#ifdef USE_33BIT_ADDRESSING
        if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
                if (!add_shm_range(strdup(shm_file), addr, size))
                        return -1;

                if (mmap((char *)addr + (1L << 32), size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED)
                        return -1;
                close(fd);
        }
#endif
#else
#ifdef HAVE_WIN32_VM
        // Windows cannot allocate Low Memory
        if (addr == NULL)
                return -1;

        // 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, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
        if (ret_addr != req_addr)
                return -1;
                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;

#ifdef USE_33BIT_ADDRESSING
        shm_range_t *r = find_shm_range(addr, size);
        if (r) {
                if (munmap((char *)r->base + (1L << 32), size) != 0)
                        return -1;

                if (shm_unlink(r->file) < 0)
                        return -1;
                free((char *)r->file);

                if (!remove_shm_range(r))
                        return -1;
        }
#endif
#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
}

/* Returns the size of a page.  */

int vm_get_page_size(void)
{
#ifdef HAVE_WIN32_VM
        static unsigned long 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_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 *)((unsigned long)(address) & -page_size))
        unsigned long 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:	1.22
Committed:	2006-02-27T00:04:12Z (18 years, 2 months ago) by gbeauche
Branch:	MAIN
Changes since 1.21:	+0 -15 lines
Log Message:	Memory allocated through win32 VirtualAlloc() is zero-filled. Likewise for memory mmap()'ed with MAP_ANONYMOUS (equivalent to /dev/zero mapping but faster)
#	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	1.17	* Basilisk II (C) 1997-2005 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	1.9	/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII
52			because the emulated target is 32-bit and this helps to allocate
53			memory so that branches could be resolved more easily (32-bit
54			displacement to code in .text), on AMD64 for example. */
55			#ifndef MAP_32BIT
56			#define MAP_32BIT 0
57			#endif
58	gbeauche	1.13	#ifndef MAP_ANON
59			#define MAP_ANON 0
60			#endif
61			#ifndef MAP_ANONYMOUS
62			#define MAP_ANONYMOUS 0
63			#endif
64	gbeauche	1.9
65			#define MAP_EXTRA_FLAGS (MAP_32BIT)
66
67	gbeauche	1.1	#ifdef HAVE_MMAP_VM
68	gbeauche	1.9	#if defined(__linux__) && defined(__i386__)
69			/* Force a reasonnable address below 0x80000000 on x86 so that we
70			don't get addresses above when the program is run on AMD64.
71			NOTE: this is empirically determined on Linux/x86. */
72			#define MAP_BASE 0x10000000
73			#else
74			#define MAP_BASE 0x00000000
75			#endif
76			static char * next_address = (char *)MAP_BASE;
77	gbeauche	1.1	#ifdef HAVE_MMAP_ANON
78	gbeauche	1.10	#define map_flags (MAP_ANON \| MAP_EXTRA_FLAGS)
79	gbeauche	1.1	#define zero_fd -1
80			#else
81			#ifdef HAVE_MMAP_ANONYMOUS
82	gbeauche	1.10	#define map_flags (MAP_ANONYMOUS \| MAP_EXTRA_FLAGS)
83	gbeauche	1.1	#define zero_fd -1
84			#else
85	gbeauche	1.10	#define map_flags (MAP_EXTRA_FLAGS)
86	gbeauche	1.1	static int zero_fd = -1;
87			#endif
88			#endif
89			#endif
90
91	gbeauche	1.13	/* Utility functions for POSIX SHM handling. */
92
93			#ifdef USE_33BIT_ADDRESSING
94			struct shm_range_t {
95			const char *file;
96			void *base;
97			unsigned int size;
98			shm_range_t *next;
99			};
100
101			static shm_range_t *shm_ranges = NULL;
102
103			static bool add_shm_range(const char file, void base, unsigned int size)
104			{
105			shm_range_t r = (shm_range_t )malloc(sizeof(shm_range_t));
106			if (r) {
107			r->file = file;
108			r->base = base;
109			r->size = size;
110			r->next = shm_ranges ? shm_ranges : NULL;
111			shm_ranges = r;
112			return true;
113			}
114			return false;
115			}
116
117			static shm_range_t find_shm_range(void base, unsigned int size)
118			{
119			for (shm_range_t *r = shm_ranges; r != NULL; r = r->next)
120			if (r->base == base && r->size == size)
121			return r;
122			return NULL;
123			}
124
125			static bool remove_shm_range(shm_range_t *r)
126			{
127			if (r) {
128			for (shm_range_t *p = shm_ranges; p != NULL; p = p->next) {
129			if (p->next == r) {
130			p->next = r->next;
131			free(r);
132			return true;
133			}
134			}
135			}
136			return false;
137			}
138
139			static bool remove_shm_range(void *base, unsigned int size)
140			{
141			remove_shm_range(find_shm_range(base, size));
142			}
143			#endif
144
145			/* Build a POSIX SHM memory segment file descriptor name. */
146
147			#ifdef USE_33BIT_ADDRESSING
148			static const char *build_shm_filename(void)
149			{
150			static int id = 0;
151			static char filename[PATH_MAX];
152
153			int ret = snprintf(filename, sizeof(filename), "/BasiliskII-%d-shm-%d", getpid(), id);
154			if (ret == -1 \|\| ret >= sizeof(filename))
155			return NULL;
156
157			id++;
158			return filename;
159			}
160			#endif
161
162	gbeauche	1.10	/* Translate generic VM map flags to host values. */
163
164			#ifdef HAVE_MMAP_VM
165			static int translate_map_flags(int vm_flags)
166			{
167			int flags = 0;
168			if (vm_flags & VM_MAP_SHARED)
169			flags \|= MAP_SHARED;
170			if (vm_flags & VM_MAP_PRIVATE)
171			flags \|= MAP_PRIVATE;
172			if (vm_flags & VM_MAP_FIXED)
173			flags \|= MAP_FIXED;
174			if (vm_flags & VM_MAP_32BIT)
175			flags \|= MAP_32BIT;
176			return flags;
177			}
178			#endif
179
180	gbeauche	1.14	/* Align ADDR and SIZE to 64K boundaries. */
181
182			#ifdef HAVE_WIN32_VM
183			static inline LPVOID align_addr_segment(LPVOID addr)
184			{
185			return (LPVOID)(((DWORD)addr) & -65536);
186			}
187
188			static inline DWORD align_size_segment(LPVOID addr, DWORD size)
189			{
190			return size + ((DWORD)addr - (DWORD)align_addr_segment(addr));
191			}
192			#endif
193
194			/* Translate generic VM prot flags to host values. */
195
196			#ifdef HAVE_WIN32_VM
197			static int translate_prot_flags(int prot_flags)
198			{
199			int prot = PAGE_READWRITE;
200			if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ \| VM_PAGE_WRITE))
201			prot = PAGE_EXECUTE_READWRITE;
202			else if (prot_flags == (VM_PAGE_EXECUTE \| VM_PAGE_READ))
203			prot = PAGE_EXECUTE_READ;
204			else if (prot_flags == (VM_PAGE_READ \| VM_PAGE_WRITE))
205			prot = PAGE_READWRITE;
206			else if (prot_flags == VM_PAGE_READ)
207			prot = PAGE_READONLY;
208			else if (prot_flags == 0)
209			prot = PAGE_NOACCESS;
210			return prot;
211			}
212			#endif
213
214	gbeauche	1.1	/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
215
216			int vm_init(void)
217			{
218			#ifdef HAVE_MMAP_VM
219			#ifndef zero_fd
220			zero_fd = open("/dev/zero", O_RDWR);
221			if (zero_fd < 0)
222			return -1;
223			#endif
224			#endif
225			return 0;
226			}
227
228			/* Deallocate all internal data used to wrap virtual memory allocators. */
229
230			void vm_exit(void)
231			{
232			#ifdef HAVE_MMAP_VM
233			#ifndef zero_fd
234	gbeauche	1.19	if (zero_fd != -1) {
235			close(zero_fd);
236			zero_fd = -1;
237			}
238	gbeauche	1.1	#endif
239			#endif
240			}
241
242			/* Allocate zero-filled memory of SIZE bytes. The mapping is private
243			and default protection bits are read / write. The return value
244			is the actual mapping address chosen or VM_MAP_FAILED for errors. */
245
246	gbeauche	1.10	void * vm_acquire(size_t size, int options)
247	gbeauche	1.1	{
248			void * addr;
249	gbeauche	1.10
250			// VM_MAP_FIXED are to be used with vm_acquire_fixed() only
251			if (options & VM_MAP_FIXED)
252			return VM_MAP_FAILED;
253
254	gbeauche	1.1	#ifdef HAVE_MACH_VM
255			// vm_allocate() returns a zero-filled memory region
256			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
257			return VM_MAP_FAILED;
258			#else
259			#ifdef HAVE_MMAP_VM
260	gbeauche	1.13	int fd = zero_fd;
261			int the_map_flags = translate_map_flags(options) \| map_flags;
262
263			#ifdef USE_33BIT_ADDRESSING
264			const char *shm_file = NULL;
265			if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
266			the_map_flags &= ~(MAP_PRIVATE \| MAP_ANON \| MAP_ANONYMOUS);
267			the_map_flags \|= MAP_SHARED;
268
269			if ((shm_file = build_shm_filename()) == NULL)
270			return VM_MAP_FAILED;
271
272			if ((fd = shm_open(shm_file, O_RDWR \| O_CREAT \| O_EXCL, 0644)) < 0)
273			return VM_MAP_FAILED;
274
275			if (ftruncate(fd, size) < 0)
276			return VM_MAP_FAILED;
277			}
278			#endif
279	gbeauche	1.10
280	gbeauche	1.13	if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED)
281	gbeauche	1.1	return VM_MAP_FAILED;
282
283	gbeauche	1.10	// Sanity checks for 64-bit platforms
284			if (sizeof(void ) == 8 && (options & VM_MAP_32BIT) && !((char )addr <= (char *)0xffffffff))
285			return VM_MAP_FAILED;
286
287	gbeauche	1.3	next_address = (char *)addr + size;
288	gbeauche	1.13
289			// Remap to 33-bit space
290			#ifdef USE_33BIT_ADDRESSING
291			if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
292			if (!add_shm_range(strdup(shm_file), addr, size))
293			return VM_MAP_FAILED;
294
295			if (mmap((char )addr + (1L << 32), size, VM_PAGE_DEFAULT, the_map_flags \| MAP_FIXED, fd, 0) == (void )MAP_FAILED)
296			return VM_MAP_FAILED;
297			close(fd);
298			}
299			#endif
300	gbeauche	1.1	#else
301	gbeauche	1.14	#ifdef HAVE_WIN32_VM
302			if ((addr = VirtualAlloc(NULL, size, MEM_RESERVE \| MEM_COMMIT, PAGE_EXECUTE_READWRITE)) == NULL)
303			return VM_MAP_FAILED;
304			#else
305	gbeauche	1.1	if ((addr = calloc(size, 1)) == 0)
306			return VM_MAP_FAILED;
307
308			// Omit changes for protections because they are not supported in this mode
309			return addr;
310			#endif
311			#endif
312	gbeauche	1.14	#endif
313	cebix	1.2
314	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
315			// say MacOS X, mmap() doesn't honour the requested protection flags.
316			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
317			return VM_MAP_FAILED;
318
319			return addr;
320			}
321
322			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
323			Retuns 0 if successful, -1 on errors. */
324
325	gbeauche	1.10	int vm_acquire_fixed(void * addr, size_t size, int options)
326	gbeauche	1.1	{
327	gbeauche	1.10	// Fixed mappings are required to be private
328			if (options & VM_MAP_SHARED)
329			return -1;
330
331	gbeauche	1.1	#ifdef HAVE_MACH_VM
332			// vm_allocate() returns a zero-filled memory region
333			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
334			return -1;
335			#else
336			#ifdef HAVE_MMAP_VM
337	gbeauche	1.21	int fd = zero_fd;
338			int the_map_flags = translate_map_flags(options) \| map_flags \| MAP_FIXED;
339	gbeauche	1.10
340	gbeauche	1.21	#ifdef USE_33BIT_ADDRESSING
341			const char *shm_file = NULL;
342			if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
343			the_map_flags &= ~(MAP_PRIVATE \| MAP_ANON \| MAP_ANONYMOUS);
344			the_map_flags \|= MAP_SHARED;
345
346			if ((shm_file = build_shm_filename()) == NULL)
347			return -1;
348
349			if ((fd = shm_open(shm_file, O_RDWR \| O_CREAT \| O_EXCL, 0644)) < 0)
350			return -1;
351
352			if (ftruncate(fd, size) < 0)
353			return -1;
354			}
355			#endif
356
357			if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void *)MAP_FAILED)
358	gbeauche	1.1	return -1;
359	gbeauche	1.21
360			// Remap to 33-bit space
361			#ifdef USE_33BIT_ADDRESSING
362			if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
363			if (!add_shm_range(strdup(shm_file), addr, size))
364			return -1;
365
366			if (mmap((char )addr + (1L << 32), size, VM_PAGE_DEFAULT, the_map_flags, fd, 0) == (void )MAP_FAILED)
367			return -1;
368			close(fd);
369			}
370			#endif
371	gbeauche	1.1	#else
372	gbeauche	1.14	#ifdef HAVE_WIN32_VM
373			// Windows cannot allocate Low Memory
374			if (addr == NULL)
375			return -1;
376
377			// Allocate a possibly offset region to align on 64K boundaries
378			LPVOID req_addr = align_addr_segment(addr);
379			DWORD req_size = align_size_segment(addr, size);
380			LPVOID ret_addr = VirtualAlloc(req_addr, req_size, MEM_COMMIT \| MEM_RESERVE, PAGE_EXECUTE_READWRITE);
381			if (ret_addr != req_addr)
382			return -1;
383			return -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			// Explicitely protect the newly mapped region here because on some systems,
392			// say MacOS X, mmap() doesn't honour the requested protection flags.
393	gbeauche	1.6	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
394	gbeauche	1.1	return -1;
395
396			return 0;
397			}
398
399			/* Deallocate any mapping for the region starting at ADDR and extending
400			LEN bytes. Returns 0 if successful, -1 on errors. */
401
402			int vm_release(void * addr, size_t size)
403			{
404	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
405			if (addr == VM_MAP_FAILED)
406			return 0;
407
408	gbeauche	1.1	#ifdef HAVE_MACH_VM
409	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
410			return -1;
411	gbeauche	1.1	#else
412			#ifdef HAVE_MMAP_VM
413	gbeauche	1.7	if (munmap((caddr_t)addr, size) != 0)
414	gbeauche	1.4	return -1;
415	gbeauche	1.13
416			#ifdef USE_33BIT_ADDRESSING
417			shm_range_t *r = find_shm_range(addr, size);
418			if (r) {
419			if (munmap((char *)r->base + (1L << 32), size) != 0)
420			return -1;
421
422			if (shm_unlink(r->file) < 0)
423			return -1;
424			free((char *)r->file);
425
426			if (!remove_shm_range(r))
427			return -1;
428			}
429			#endif
430	gbeauche	1.1	#else
431	gbeauche	1.14	#ifdef HAVE_WIN32_VM
432			if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0)
433			return -1;
434			#else
435	gbeauche	1.1	free(addr);
436			#endif
437			#endif
438	gbeauche	1.14	#endif
439	gbeauche	1.4
440			return 0;
441	gbeauche	1.1	}
442
443			/* Change the memory protection of the region starting at ADDR and
444			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
445
446			int vm_protect(void * addr, size_t size, int prot)
447			{
448			#ifdef HAVE_MACH_VM
449			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
450			return ret_code == KERN_SUCCESS ? 0 : -1;
451			#else
452			#ifdef HAVE_MMAP_VM
453	gbeauche	1.7	int ret_code = mprotect((caddr_t)addr, size, prot);
454	gbeauche	1.1	return ret_code == 0 ? 0 : -1;
455			#else
456	gbeauche	1.14	#ifdef HAVE_WIN32_VM
457			DWORD old_prot;
458			int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot);
459			return ret_code != 0 ? 0 : -1;
460			#else
461	gbeauche	1.1	// Unsupported
462			return -1;
463			#endif
464			#endif
465	gbeauche	1.14	#endif
466	gbeauche	1.1	}
467
468	gbeauche	1.15	/* Returns the size of a page. */
469
470	gbeauche	1.16	int vm_get_page_size(void)
471	gbeauche	1.15	{
472	gbeauche	1.20	#ifdef HAVE_WIN32_VM
473			static unsigned long page_size = 0;
474			if (page_size == 0) {
475			SYSTEM_INFO si;
476			GetSystemInfo(&si);
477			page_size = si.dwAllocationGranularity;
478			}
479			return page_size;
480	gbeauche	1.15	#else
481	gbeauche	1.20	return getpagesize();
482	gbeauche	1.15	#endif
483			}
484
485	gbeauche	1.1	#ifdef CONFIGURE_TEST_VM_MAP
486	gbeauche	1.18	#include <stdlib.h>
487			#include <signal.h>
488
489			static void fault_handler(int sig)
490			{
491			exit(1);
492			}
493
494	gbeauche	1.1	/* Tests covered here:
495			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
496			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
497			*/
498			int main(void)
499			{
500			vm_init();
501	gbeauche	1.18
502			signal(SIGSEGV, fault_handler);
503			#ifdef SIGBUS
504			signal(SIGBUS, fault_handler);
505			#endif
506	gbeauche	1.1
507			#define page_align(address) ((char *)((unsigned long)(address) & -page_size))
508	gbeauche	1.16	unsigned long page_size = vm_get_page_size();
509	gbeauche	1.1
510			const int area_size = 6 * page_size;
511			volatile char * area = (volatile char *) vm_acquire(area_size);
512			volatile char * fault_address = area + (page_size * 7) / 2;
513
514			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
515			if (area == VM_MAP_FAILED)
516			return 1;
517
518			if (vm_release((char *)area, area_size) < 0)
519			return 1;
520
521			return 0;
522			#endif
523
524			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
525			if (area == VM_MAP_FAILED)
526			return 0;
527
528			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
529			return 0;
530			#endif
531
532			#if defined(TEST_VM_PROT_RDWR_WRITE)
533			if (area == VM_MAP_FAILED)
534			return 1;
535
536			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
537			return 1;
538
539			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
540			return 1;
541			#endif
542
543			#if defined(TEST_VM_PROT_READ_WRITE)
544			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
545			return 0;
546			#endif
547
548			#if defined(TEST_VM_PROT_NONE_READ)
549			// this should cause a core dump
550			char foo = *fault_address;
551			return 0;
552			#endif
553
554			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
555			// this should cause a core dump
556			*fault_address = 'z';
557			return 0;
558			#endif
559
560			#if defined(TEST_VM_PROT_RDWR_WRITE)
561			// this should not cause a core dump
562			*fault_address = 'z';
563			return 0;
564			#endif
565			}
566			#endif