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) 1997-2001 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

// TODO: Win32 VMs ?
#include <stdlib.h>
#include <string.h>
#include "vm_alloc.h"

#ifdef HAVE_MACH_VM
#ifndef HAVE_MACH_TASK_SELF
#ifdef HAVE_TASK_SELF
#define mach_task_self task_self
#else
#error "No task_self(), you lose."
#endif
#endif
#endif

#ifdef HAVE_MMAP_VM
#ifdef HAVE_MMAP_ANON
#define map_flags       (MAP_PRIVATE | MAP_ANON)
#define zero_fd         -1
#else
#ifdef HAVE_MMAP_ANONYMOUS
#define map_flags       (MAP_PRIVATE | MAP_ANONYMOUS)
#define zero_fd         -1
#else
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#define map_flags       (MAP_PRIVATE)
static int zero_fd      = -1;
#endif
#endif
#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)
{
        void * addr;
        
#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
        if ((addr = mmap(0, size, VM_PAGE_DEFAULT, map_flags, zero_fd, 0)) == MAP_FAILED)
                return VM_MAP_FAILED;
        
        // Since I don't know the standard behavior of mmap(), zero-fill here
        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
        
        // 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)
{
#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
        if (mmap(addr, size, VM_PAGE_DEFAULT, map_flags | MAP_FIXED, zero_fd, 0) == MAP_FAILED)
                return -1;
        
        // Since I don't know the standard behavior of mmap(), zero-fill here
        if (memset(0, 0, size) != 0)
                return -1;
#else
        // Unsupported
        return -1;
#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(0, 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)
{
#ifdef HAVE_MACH_VM
        int ret_code = vm_deallocate(mach_task_self(), (vm_address_t)addr, size);
        return ret_code == KERN_SUCCESS ? 0 : -1;
#else
#ifdef HAVE_MMAP_VM
        int ret_code = munmap(addr, size);
        return ret_code == 0 ? 0 : -1;
#else
        free(addr);
        return 0;
#endif
#endif
}

/* 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(addr, size, prot);
        return ret_code == 0 ? 0 : -1;
#else
        // Unsupported
        return -1;
#endif
#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 = getpagesize();
        
        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:	1.1
Committed:	2001-06-26T22:35:41Z (23 years ago) by gbeauche
Branch:	MAIN
Log Message:	- added SIGSEGV support for Linux/Alpha (to be checked), Darwin/PPC - added uniform virtual memory allocation (supports mmap(), vm_allocate(), or fallbacks to malloc()/free()) - cleaned up memory allocation in main_unix.cpp
#	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			* Basilisk II (C) 1997-2001 Christian Bauer
6			*
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			// TODO: Win32 VMs ?
27			#include <stdlib.h>
28			#include <string.h>
29			#include "vm_alloc.h"
30
31			#ifdef HAVE_MACH_VM
32			#ifndef HAVE_MACH_TASK_SELF
33			#ifdef HAVE_TASK_SELF
34			#define mach_task_self task_self
35			#else
36			#error "No task_self(), you lose."
37			#endif
38			#endif
39			#endif
40
41			#ifdef HAVE_MMAP_VM
42			#ifdef HAVE_MMAP_ANON
43			#define map_flags (MAP_PRIVATE \| MAP_ANON)
44			#define zero_fd -1
45			#else
46			#ifdef HAVE_MMAP_ANONYMOUS
47			#define map_flags (MAP_PRIVATE \| MAP_ANONYMOUS)
48			#define zero_fd -1
49			#else
50			#ifdef HAVE_FCNTL_H
51			#include <fcntl.h>
52			#endif
53			#define map_flags (MAP_PRIVATE)
54			static int zero_fd = -1;
55			#endif
56			#endif
57			#endif
58
59			/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
60
61			int vm_init(void)
62			{
63			#ifdef HAVE_MMAP_VM
64			#ifndef zero_fd
65			zero_fd = open("/dev/zero", O_RDWR);
66			if (zero_fd < 0)
67			return -1;
68			#endif
69			#endif
70			return 0;
71			}
72
73			/* Deallocate all internal data used to wrap virtual memory allocators. */
74
75			void vm_exit(void)
76			{
77			#ifdef HAVE_MMAP_VM
78			#ifndef zero_fd
79			close(zero_fd);
80			#endif
81			#endif
82			}
83
84			/* Allocate zero-filled memory of SIZE bytes. The mapping is private
85			and default protection bits are read / write. The return value
86			is the actual mapping address chosen or VM_MAP_FAILED for errors. */
87
88			void * vm_acquire(size_t size)
89			{
90			void * addr;
91
92			#ifdef HAVE_MACH_VM
93			// vm_allocate() returns a zero-filled memory region
94			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
95			return VM_MAP_FAILED;
96			#else
97			#ifdef HAVE_MMAP_VM
98			if ((addr = mmap(0, size, VM_PAGE_DEFAULT, map_flags, zero_fd, 0)) == MAP_FAILED)
99			return VM_MAP_FAILED;
100
101			// Since I don't know the standard behavior of mmap(), zero-fill here
102			if (memset(addr, 0, size) != addr)
103			return VM_MAP_FAILED;
104			#else
105			if ((addr = calloc(size, 1)) == 0)
106			return VM_MAP_FAILED;
107
108			// Omit changes for protections because they are not supported in this mode
109			return addr;
110			#endif
111			#endif
112
113			// Explicitely protect the newly mapped region here because on some systems,
114			// say MacOS X, mmap() doesn't honour the requested protection flags.
115			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
116			return VM_MAP_FAILED;
117
118			return addr;
119			}
120
121			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
122			Retuns 0 if successful, -1 on errors. */
123
124			int vm_acquire_fixed(void * addr, size_t size)
125			{
126			#ifdef HAVE_MACH_VM
127			// vm_allocate() returns a zero-filled memory region
128			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
129			return -1;
130			#else
131			#ifdef HAVE_MMAP_VM
132			if (mmap(addr, size, VM_PAGE_DEFAULT, map_flags \| MAP_FIXED, zero_fd, 0) == MAP_FAILED)
133			return -1;
134
135			// Since I don't know the standard behavior of mmap(), zero-fill here
136			if (memset(0, 0, size) != 0)
137			return -1;
138			#else
139			// Unsupported
140			return -1;
141			#endif
142			#endif
143
144			// Explicitely protect the newly mapped region here because on some systems,
145			// say MacOS X, mmap() doesn't honour the requested protection flags.
146			if (vm_protect(0, size, VM_PAGE_DEFAULT) != 0)
147			return -1;
148
149			return 0;
150			}
151
152			/* Deallocate any mapping for the region starting at ADDR and extending
153			LEN bytes. Returns 0 if successful, -1 on errors. */
154
155			int vm_release(void * addr, size_t size)
156			{
157			#ifdef HAVE_MACH_VM
158			int ret_code = vm_deallocate(mach_task_self(), (vm_address_t)addr, size);
159			return ret_code == KERN_SUCCESS ? 0 : -1;
160			#else
161			#ifdef HAVE_MMAP_VM
162			int ret_code = munmap(addr, size);
163			return ret_code == 0 ? 0 : -1;
164			#else
165			free(addr);
166			return 0;
167			#endif
168			#endif
169			}
170
171			/* Change the memory protection of the region starting at ADDR and
172			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
173
174			int vm_protect(void * addr, size_t size, int prot)
175			{
176			#ifdef HAVE_MACH_VM
177			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
178			return ret_code == KERN_SUCCESS ? 0 : -1;
179			#else
180			#ifdef HAVE_MMAP_VM
181			int ret_code = mprotect(addr, size, prot);
182			return ret_code == 0 ? 0 : -1;
183			#else
184			// Unsupported
185			return -1;
186			#endif
187			#endif
188			}
189
190			#ifdef CONFIGURE_TEST_VM_MAP
191			/* Tests covered here:
192			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
193			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
194			*/
195			int main(void)
196			{
197			vm_init();
198
199			#define page_align(address) ((char *)((unsigned long)(address) & -page_size))
200			unsigned long page_size = getpagesize();
201
202			const int area_size = 6 * page_size;
203			volatile char * area = (volatile char *) vm_acquire(area_size);
204			volatile char * fault_address = area + (page_size * 7) / 2;
205
206			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
207			if (area == VM_MAP_FAILED)
208			return 1;
209
210			if (vm_release((char *)area, area_size) < 0)
211			return 1;
212
213			return 0;
214			#endif
215
216			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
217			if (area == VM_MAP_FAILED)
218			return 0;
219
220			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
221			return 0;
222			#endif
223
224			#if defined(TEST_VM_PROT_RDWR_WRITE)
225			if (area == VM_MAP_FAILED)
226			return 1;
227
228			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
229			return 1;
230
231			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
232			return 1;
233			#endif
234
235			#if defined(TEST_VM_PROT_READ_WRITE)
236			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
237			return 0;
238			#endif
239
240			#if defined(TEST_VM_PROT_NONE_READ)
241			// this should cause a core dump
242			char foo = *fault_address;
243			return 0;
244			#endif
245
246			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
247			// this should cause a core dump
248			*fault_address = 'z';
249			return 0;
250			#endif
251
252			#if defined(TEST_VM_PROT_RDWR_WRITE)
253			// this should not cause a core dump
254			*fault_address = 'z';
255			return 0;
256			#endif
257			}
258			#endif