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;

                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
#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:	1.19
Committed:	2005-06-06T19:40:17Z (19 years, 5 months ago) by gbeauche
Branch:	MAIN
Changes since 1.18:	+4 -1 lines
Log Message:	Robustify: only close zero_fd if actually allocated
#	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			the_map_flags \|= MAP_SHARED;
279			}
280			#endif
281	gbeauche	1.10
282	gbeauche	1.13	if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, the_map_flags, fd, 0)) == (void *)MAP_FAILED)
283	gbeauche	1.1	return VM_MAP_FAILED;
284
285	gbeauche	1.10	// Sanity checks for 64-bit platforms
286			if (sizeof(void ) == 8 && (options & VM_MAP_32BIT) && !((char )addr <= (char *)0xffffffff))
287			return VM_MAP_FAILED;
288
289	gbeauche	1.3	next_address = (char *)addr + size;
290
291	gbeauche	1.1	// Since I don't know the standard behavior of mmap(), zero-fill here
292			if (memset(addr, 0, size) != addr)
293			return VM_MAP_FAILED;
294	gbeauche	1.13
295			// Remap to 33-bit space
296			#ifdef USE_33BIT_ADDRESSING
297			if (sizeof(void *) == 8 && (options & VM_MAP_33BIT)) {
298			if (!add_shm_range(strdup(shm_file), addr, size))
299			return VM_MAP_FAILED;
300
301			if (mmap((char )addr + (1L << 32), size, VM_PAGE_DEFAULT, the_map_flags \| MAP_FIXED, fd, 0) == (void )MAP_FAILED)
302			return VM_MAP_FAILED;
303			close(fd);
304			}
305			#endif
306	gbeauche	1.1	#else
307	gbeauche	1.14	#ifdef HAVE_WIN32_VM
308			if ((addr = VirtualAlloc(NULL, size, MEM_RESERVE \| MEM_COMMIT, PAGE_EXECUTE_READWRITE)) == NULL)
309			return VM_MAP_FAILED;
310
311			// Zero newly allocated memory
312			if (memset(addr, 0, size) != addr)
313			return VM_MAP_FAILED;
314			#else
315	gbeauche	1.1	if ((addr = calloc(size, 1)) == 0)
316			return VM_MAP_FAILED;
317
318			// Omit changes for protections because they are not supported in this mode
319			return addr;
320			#endif
321			#endif
322	gbeauche	1.14	#endif
323	cebix	1.2
324	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
325			// say MacOS X, mmap() doesn't honour the requested protection flags.
326			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
327			return VM_MAP_FAILED;
328
329			return addr;
330			}
331
332			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
333			Retuns 0 if successful, -1 on errors. */
334
335	gbeauche	1.10	int vm_acquire_fixed(void * addr, size_t size, int options)
336	gbeauche	1.1	{
337	gbeauche	1.10	// Fixed mappings are required to be private
338			if (options & VM_MAP_SHARED)
339			return -1;
340
341	gbeauche	1.1	#ifdef HAVE_MACH_VM
342			// vm_allocate() returns a zero-filled memory region
343			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
344			return -1;
345			#else
346			#ifdef HAVE_MMAP_VM
347	gbeauche	1.10	const int extra_map_flags = translate_map_flags(options);
348
349	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)
350	gbeauche	1.1	return -1;
351
352			// Since I don't know the standard behavior of mmap(), zero-fill here
353	gbeauche	1.8	if (memset(addr, 0, size) != addr)
354	gbeauche	1.1	return -1;
355			#else
356	gbeauche	1.14	#ifdef HAVE_WIN32_VM
357			// Windows cannot allocate Low Memory
358			if (addr == NULL)
359			return -1;
360
361			// Allocate a possibly offset region to align on 64K boundaries
362			LPVOID req_addr = align_addr_segment(addr);
363			DWORD req_size = align_size_segment(addr, size);
364			LPVOID ret_addr = VirtualAlloc(req_addr, req_size, MEM_COMMIT \| MEM_RESERVE, PAGE_EXECUTE_READWRITE);
365			if (ret_addr != req_addr)
366			return -1;
367
368			// Zero newly allocated memory
369			if (memset(addr, 0, size) != addr)
370			return -1;
371			#else
372	gbeauche	1.1	// Unsupported
373			return -1;
374			#endif
375			#endif
376	gbeauche	1.14	#endif
377	gbeauche	1.1
378			// Explicitely protect the newly mapped region here because on some systems,
379			// say MacOS X, mmap() doesn't honour the requested protection flags.
380	gbeauche	1.6	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
381	gbeauche	1.1	return -1;
382
383			return 0;
384			}
385
386			/* Deallocate any mapping for the region starting at ADDR and extending
387			LEN bytes. Returns 0 if successful, -1 on errors. */
388
389			int vm_release(void * addr, size_t size)
390			{
391	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
392			if (addr == VM_MAP_FAILED)
393			return 0;
394
395	gbeauche	1.1	#ifdef HAVE_MACH_VM
396	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
397			return -1;
398	gbeauche	1.1	#else
399			#ifdef HAVE_MMAP_VM
400	gbeauche	1.7	if (munmap((caddr_t)addr, size) != 0)
401	gbeauche	1.4	return -1;
402	gbeauche	1.13
403			#ifdef USE_33BIT_ADDRESSING
404			shm_range_t *r = find_shm_range(addr, size);
405			if (r) {
406			if (munmap((char *)r->base + (1L << 32), size) != 0)
407			return -1;
408
409			if (shm_unlink(r->file) < 0)
410			return -1;
411			free((char *)r->file);
412
413			if (!remove_shm_range(r))
414			return -1;
415			}
416			#endif
417	gbeauche	1.1	#else
418	gbeauche	1.14	#ifdef HAVE_WIN32_VM
419			if (VirtualFree(align_addr_segment(addr), 0, MEM_RELEASE) == 0)
420			return -1;
421			#else
422	gbeauche	1.1	free(addr);
423			#endif
424			#endif
425	gbeauche	1.14	#endif
426	gbeauche	1.4
427			return 0;
428	gbeauche	1.1	}
429
430			/* Change the memory protection of the region starting at ADDR and
431			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
432
433			int vm_protect(void * addr, size_t size, int prot)
434			{
435			#ifdef HAVE_MACH_VM
436			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
437			return ret_code == KERN_SUCCESS ? 0 : -1;
438			#else
439			#ifdef HAVE_MMAP_VM
440	gbeauche	1.7	int ret_code = mprotect((caddr_t)addr, size, prot);
441	gbeauche	1.1	return ret_code == 0 ? 0 : -1;
442			#else
443	gbeauche	1.14	#ifdef HAVE_WIN32_VM
444			DWORD old_prot;
445			int ret_code = VirtualProtect(addr, size, translate_prot_flags(prot), &old_prot);
446			return ret_code != 0 ? 0 : -1;
447			#else
448	gbeauche	1.1	// Unsupported
449			return -1;
450			#endif
451			#endif
452	gbeauche	1.14	#endif
453	gbeauche	1.1	}
454
455	gbeauche	1.15	/* Returns the size of a page. */
456
457	gbeauche	1.16	int vm_get_page_size(void)
458	gbeauche	1.15	{
459			#ifdef _WIN32
460			return 4096;
461			#else
462			return getpagesize();
463			#endif
464			}
465
466	gbeauche	1.1	#ifdef CONFIGURE_TEST_VM_MAP
467	gbeauche	1.18	#include <stdlib.h>
468			#include <signal.h>
469
470			static void fault_handler(int sig)
471			{
472			exit(1);
473			}
474
475	gbeauche	1.1	/* Tests covered here:
476			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
477			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
478			*/
479			int main(void)
480			{
481			vm_init();
482	gbeauche	1.18
483			signal(SIGSEGV, fault_handler);
484			#ifdef SIGBUS
485			signal(SIGBUS, fault_handler);
486			#endif
487	gbeauche	1.1
488			#define page_align(address) ((char *)((unsigned long)(address) & -page_size))
489	gbeauche	1.16	unsigned long page_size = vm_get_page_size();
490	gbeauche	1.1
491			const int area_size = 6 * page_size;
492			volatile char * area = (volatile char *) vm_acquire(area_size);
493			volatile char * fault_address = area + (page_size * 7) / 2;
494
495			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
496			if (area == VM_MAP_FAILED)
497			return 1;
498
499			if (vm_release((char *)area, area_size) < 0)
500			return 1;
501
502			return 0;
503			#endif
504
505			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
506			if (area == VM_MAP_FAILED)
507			return 0;
508
509			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
510			return 0;
511			#endif
512
513			#if defined(TEST_VM_PROT_RDWR_WRITE)
514			if (area == VM_MAP_FAILED)
515			return 1;
516
517			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
518			return 1;
519
520			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
521			return 1;
522			#endif
523
524			#if defined(TEST_VM_PROT_READ_WRITE)
525			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
526			return 0;
527			#endif
528
529			#if defined(TEST_VM_PROT_NONE_READ)
530			// this should cause a core dump
531			char foo = *fault_address;
532			return 0;
533			#endif
534
535			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
536			// this should cause a core dump
537			*fault_address = 'z';
538			return 0;
539			#endif
540
541			#if defined(TEST_VM_PROT_RDWR_WRITE)
542			// this should not cause a core dump
543			*fault_address = 'z';
544			return 0;
545			#endif
546			}
547			#endif