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
        close(zero_fd);
#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;

                the_map_flags |= MAP_SHARED;
        }
#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;
        
        // Since I don't know the standard behavior of mmap(), zero-fill here
        if (memset(addr, 0, size) != addr)
                return VM_MAP_FAILED;

        // 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;

        // Zero newly allocated memory
        if (memset(addr, 0, size) != addr)
                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
        const int extra_map_flags = translate_map_flags(options);

        if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, extra_map_flags | map_flags | MAP_FIXED, zero_fd, 0) == (void *)MAP_FAILED)
                return -1;
        
        // Since I don't know the standard behavior of mmap(), zero-fill here
        if (memset(addr, 0, size) != addr)
                return -1;
#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;

        // Zero newly allocated memory
        if (memset(addr, 0, size) != 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;

#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 _WIN32
    return 4096;
#else
    return getpagesize();
#endif
}

#ifdef CONFIGURE_TEST_VM_MAP
/* 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();
        
#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:	1.17
Committed:	2005-01-30T21:42:14Z (19 years, 7 months ago) by gbeauche
Branch:	MAIN
Changes since 1.16:	+1 -1 lines
Log Message:	Happy New Year!
#	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			close(zero_fd);
235			#endif
236			#endif
237			}
238
239			/* Allocate zero-filled memory of SIZE bytes. The mapping is private
240			and default protection bits are read / write. The return value
241			is the actual mapping address chosen or VM_MAP_FAILED for errors. */
242
243	gbeauche	1.10	void * vm_acquire(size_t size, int options)
244	gbeauche	1.1	{
245			void * addr;
246	gbeauche	1.10
247			// VM_MAP_FIXED are to be used with vm_acquire_fixed() only
248			if (options & VM_MAP_FIXED)
249			return VM_MAP_FAILED;
250
251	gbeauche	1.1	#ifdef HAVE_MACH_VM
252			// vm_allocate() returns a zero-filled memory region
253			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
254			return VM_MAP_FAILED;
255			#else
256			#ifdef HAVE_MMAP_VM
257	gbeauche	1.13	int fd = zero_fd;
258			int the_map_flags = translate_map_flags(options) \| map_flags;
259
260			#ifdef USE_33BIT_ADDRESSING
261			const char *shm_file = NULL;
262			if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
263			the_map_flags &= ~(MAP_PRIVATE \| MAP_ANON \| MAP_ANONYMOUS);
264			the_map_flags \|= MAP_SHARED;
265
266			if ((shm_file = build_shm_filename()) == NULL)
267			return VM_MAP_FAILED;
268
269			if ((fd = shm_open(shm_file, O_RDWR \| O_CREAT \| O_EXCL, 0644)) < 0)
270			return VM_MAP_FAILED;
271
272			if (ftruncate(fd, size) < 0)
273			return VM_MAP_FAILED;
274
275			the_map_flags \|= MAP_SHARED;
276			}
277			#endif
278	gbeauche	1.10
279	gbeauche	1.13	if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED)
280	gbeauche	1.1	return VM_MAP_FAILED;
281
282	gbeauche	1.10	// Sanity checks for 64-bit platforms
283			if (sizeof(void ) == 8 && (options & VM_MAP_32BIT) && !((char )addr <= (char *)0xffffffff))
284			return VM_MAP_FAILED;
285
286	gbeauche	1.3	next_address = (char *)addr + size;
287
288	gbeauche	1.1	// Since I don't know the standard behavior of mmap(), zero-fill here
289			if (memset(addr, 0, size) != addr)
290			return VM_MAP_FAILED;
291	gbeauche	1.13
292			// Remap to 33-bit space
293			#ifdef USE_33BIT_ADDRESSING
294			if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
295			if (!add_shm_range(strdup(shm_file), addr, size))
296			return VM_MAP_FAILED;
297
298			if (mmap((char )addr + (1L << 32), size, VM_PAGE_DEFAULT, the_map_flags \| MAP_FIXED, fd, 0) == (void )MAP_FAILED)
299			return VM_MAP_FAILED;
300			close(fd);
301			}
302			#endif
303	gbeauche	1.1	#else
304	gbeauche	1.14	#ifdef HAVE_WIN32_VM
305			if ((addr = VirtualAlloc(NULL, size, MEM_RESERVE \| MEM_COMMIT, PAGE_EXECUTE_READWRITE)) == NULL)
306			return VM_MAP_FAILED;
307
308			// Zero newly allocated memory
309			if (memset(addr, 0, size) != addr)
310			return VM_MAP_FAILED;
311			#else
312	gbeauche	1.1	if ((addr = calloc(size, 1)) == 0)
313			return VM_MAP_FAILED;
314
315			// Omit changes for protections because they are not supported in this mode
316			return addr;
317			#endif
318			#endif
319	gbeauche	1.14	#endif
320	cebix	1.2
321	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
322			// say MacOS X, mmap() doesn't honour the requested protection flags.
323			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
324			return VM_MAP_FAILED;
325
326			return addr;
327			}
328
329			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
330			Retuns 0 if successful, -1 on errors. */
331
332	gbeauche	1.10	int vm_acquire_fixed(void * addr, size_t size, int options)
333	gbeauche	1.1	{
334	gbeauche	1.10	// Fixed mappings are required to be private
335			if (options & VM_MAP_SHARED)
336			return -1;
337
338	gbeauche	1.1	#ifdef HAVE_MACH_VM
339			// vm_allocate() returns a zero-filled memory region
340			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
341			return -1;
342			#else
343			#ifdef HAVE_MMAP_VM
344	gbeauche	1.10	const int extra_map_flags = translate_map_flags(options);
345
346	gbeauche	1.11	if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, extra_map_flags \| map_flags \| MAP_FIXED, zero_fd, 0) == (void *)MAP_FAILED)
347	gbeauche	1.1	return -1;
348
349			// Since I don't know the standard behavior of mmap(), zero-fill here
350	gbeauche	1.8	if (memset(addr, 0, size) != addr)
351	gbeauche	1.1	return -1;
352			#else
353	gbeauche	1.14	#ifdef HAVE_WIN32_VM
354			// Windows cannot allocate Low Memory
355			if (addr == NULL)
356			return -1;
357
358			// Allocate a possibly offset region to align on 64K boundaries
359			LPVOID req_addr = align_addr_segment(addr);
360			DWORD req_size = align_size_segment(addr, size);
361			LPVOID ret_addr = VirtualAlloc(req_addr, req_size, MEM_COMMIT \| MEM_RESERVE, PAGE_EXECUTE_READWRITE);
362			if (ret_addr != req_addr)
363			return -1;
364
365			// Zero newly allocated memory
366			if (memset(addr, 0, size) != addr)
367			return -1;
368			#else
369	gbeauche	1.1	// Unsupported
370			return -1;
371			#endif
372			#endif
373	gbeauche	1.14	#endif
374	gbeauche	1.1
375			// Explicitely protect the newly mapped region here because on some systems,
376			// say MacOS X, mmap() doesn't honour the requested protection flags.
377	gbeauche	1.6	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
378	gbeauche	1.1	return -1;
379
380			return 0;
381			}
382
383			/* Deallocate any mapping for the region starting at ADDR and extending
384			LEN bytes. Returns 0 if successful, -1 on errors. */
385
386			int vm_release(void * addr, size_t size)
387			{
388	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
389			if (addr == VM_MAP_FAILED)
390			return 0;
391
392	gbeauche	1.1	#ifdef HAVE_MACH_VM
393	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
394			return -1;
395	gbeauche	1.1	#else
396			#ifdef HAVE_MMAP_VM
397	gbeauche	1.7	if (munmap((caddr_t)addr, size) != 0)
398	gbeauche	1.4	return -1;
399	gbeauche	1.13
400			#ifdef USE_33BIT_ADDRESSING
401			shm_range_t *r = find_shm_range(addr, size);
402			if (r) {
403			if (munmap((char *)r->base + (1L << 32), size) != 0)
404			return -1;
405
406			if (shm_unlink(r->file) < 0)
407			return -1;
408			free((char *)r->file);
409
410			if (!remove_shm_range(r))
411			return -1;
412			}
413			#endif
414	gbeauche	1.1	#else
415	gbeauche	1.14	#ifdef HAVE_WIN32_VM
416			if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0)
417			return -1;
418			#else
419	gbeauche	1.1	free(addr);
420			#endif
421			#endif
422	gbeauche	1.14	#endif
423	gbeauche	1.4
424			return 0;
425	gbeauche	1.1	}
426
427			/* Change the memory protection of the region starting at ADDR and
428			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
429
430			int vm_protect(void * addr, size_t size, int prot)
431			{
432			#ifdef HAVE_MACH_VM
433			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
434			return ret_code == KERN_SUCCESS ? 0 : -1;
435			#else
436			#ifdef HAVE_MMAP_VM
437	gbeauche	1.7	int ret_code = mprotect((caddr_t)addr, size, prot);
438	gbeauche	1.1	return ret_code == 0 ? 0 : -1;
439			#else
440	gbeauche	1.14	#ifdef HAVE_WIN32_VM
441			DWORD old_prot;
442			int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot);
443			return ret_code != 0 ? 0 : -1;
444			#else
445	gbeauche	1.1	// Unsupported
446			return -1;
447			#endif
448			#endif
449	gbeauche	1.14	#endif
450	gbeauche	1.1	}
451
452	gbeauche	1.15	/* Returns the size of a page. */
453
454	gbeauche	1.16	int vm_get_page_size(void)
455	gbeauche	1.15	{
456			#ifdef _WIN32
457			return 4096;
458			#else
459			return getpagesize();
460			#endif
461			}
462
463	gbeauche	1.1	#ifdef CONFIGURE_TEST_VM_MAP
464			/* Tests covered here:
465			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
466			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
467			*/
468			int main(void)
469			{
470			vm_init();
471
472			#define page_align(address) ((char *)((unsigned long)(address) & -page_size))
473	gbeauche	1.16	unsigned long page_size = vm_get_page_size();
474	gbeauche	1.1
475			const int area_size = 6 * page_size;
476			volatile char * area = (volatile char *) vm_acquire(area_size);
477			volatile char * fault_address = area + (page_size * 7) / 2;
478
479			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
480			if (area == VM_MAP_FAILED)
481			return 1;
482
483			if (vm_release((char *)area, area_size) < 0)
484			return 1;
485
486			return 0;
487			#endif
488
489			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
490			if (area == VM_MAP_FAILED)
491			return 0;
492
493			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
494			return 0;
495			#endif
496
497			#if defined(TEST_VM_PROT_RDWR_WRITE)
498			if (area == VM_MAP_FAILED)
499			return 1;
500
501			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
502			return 1;
503
504			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
505			return 1;
506			#endif
507
508			#if defined(TEST_VM_PROT_READ_WRITE)
509			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
510			return 0;
511			#endif
512
513			#if defined(TEST_VM_PROT_NONE_READ)
514			// this should cause a core dump
515			char foo = *fault_address;
516			return 0;
517			#endif
518
519			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
520			// this should cause a core dump
521			*fault_address = 'z';
522			return 0;
523			#endif
524
525			#if defined(TEST_VM_PROT_RDWR_WRITE)
526			// this should not cause a core dump
527			*fault_address = 'z';
528			return 0;
529			#endif
530			}
531			#endif