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) 1997-2002 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
static char * next_address = 0;
#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(next_address, size, VM_PAGE_DEFAULT, map_flags, zero_fd, 0)) == MAP_FAILED)
                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;
#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)
{
        // 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(addr, size) != 0)
                return -1;
#else
        free(addr);
#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(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:	1.5
Committed:	2002-01-15T14:58:37Z (22 years, 10 months ago) by cebix
Branch:	MAIN
CVS Tags:	snapshot-15012002
Changes since 1.4:	+1 -1 lines
Log Message:	- documentation updates - 2001 -> 2002 - version 0.9 -> 1.0
#	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	cebix	1.5	* Basilisk II (C) 1997-2002 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			// 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	gbeauche	1.3	static char * next_address = 0;
43	gbeauche	1.1	#ifdef HAVE_MMAP_ANON
44			#define map_flags (MAP_PRIVATE \| MAP_ANON)
45			#define zero_fd -1
46			#else
47			#ifdef HAVE_MMAP_ANONYMOUS
48			#define map_flags (MAP_PRIVATE \| MAP_ANONYMOUS)
49			#define zero_fd -1
50			#else
51			#ifdef HAVE_FCNTL_H
52			#include <fcntl.h>
53			#endif
54			#define map_flags (MAP_PRIVATE)
55			static int zero_fd = -1;
56			#endif
57			#endif
58			#endif
59
60			/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
61
62			int vm_init(void)
63			{
64			#ifdef HAVE_MMAP_VM
65			#ifndef zero_fd
66			zero_fd = open("/dev/zero", O_RDWR);
67			if (zero_fd < 0)
68			return -1;
69			#endif
70			#endif
71			return 0;
72			}
73
74			/* Deallocate all internal data used to wrap virtual memory allocators. */
75
76			void vm_exit(void)
77			{
78			#ifdef HAVE_MMAP_VM
79			#ifndef zero_fd
80			close(zero_fd);
81			#endif
82			#endif
83			}
84
85			/* Allocate zero-filled memory of SIZE bytes. The mapping is private
86			and default protection bits are read / write. The return value
87			is the actual mapping address chosen or VM_MAP_FAILED for errors. */
88
89			void * vm_acquire(size_t size)
90			{
91			void * addr;
92
93			#ifdef HAVE_MACH_VM
94			// vm_allocate() returns a zero-filled memory region
95			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
96			return VM_MAP_FAILED;
97			#else
98			#ifdef HAVE_MMAP_VM
99	gbeauche	1.3	if ((addr = mmap(next_address, size, VM_PAGE_DEFAULT, map_flags, zero_fd, 0)) == MAP_FAILED)
100	gbeauche	1.1	return VM_MAP_FAILED;
101
102	gbeauche	1.3	next_address = (char *)addr + size;
103
104	gbeauche	1.1	// Since I don't know the standard behavior of mmap(), zero-fill here
105			if (memset(addr, 0, size) != addr)
106			return VM_MAP_FAILED;
107			#else
108			if ((addr = calloc(size, 1)) == 0)
109			return VM_MAP_FAILED;
110
111			// Omit changes for protections because they are not supported in this mode
112			return addr;
113			#endif
114			#endif
115	cebix	1.2
116	gbeauche	1.1	// Explicitely protect the newly mapped region here because on some systems,
117			// say MacOS X, mmap() doesn't honour the requested protection flags.
118			if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
119			return VM_MAP_FAILED;
120
121			return addr;
122			}
123
124			/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
125			Retuns 0 if successful, -1 on errors. */
126
127			int vm_acquire_fixed(void * addr, size_t size)
128			{
129			#ifdef HAVE_MACH_VM
130			// vm_allocate() returns a zero-filled memory region
131			if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
132			return -1;
133			#else
134			#ifdef HAVE_MMAP_VM
135			if (mmap(addr, size, VM_PAGE_DEFAULT, map_flags \| MAP_FIXED, zero_fd, 0) == MAP_FAILED)
136			return -1;
137
138			// Since I don't know the standard behavior of mmap(), zero-fill here
139			if (memset(0, 0, size) != 0)
140			return -1;
141			#else
142			// Unsupported
143			return -1;
144			#endif
145			#endif
146
147			// Explicitely protect the newly mapped region here because on some systems,
148			// say MacOS X, mmap() doesn't honour the requested protection flags.
149			if (vm_protect(0, size, VM_PAGE_DEFAULT) != 0)
150			return -1;
151
152			return 0;
153			}
154
155			/* Deallocate any mapping for the region starting at ADDR and extending
156			LEN bytes. Returns 0 if successful, -1 on errors. */
157
158			int vm_release(void * addr, size_t size)
159			{
160	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
161			if (addr == VM_MAP_FAILED)
162			return 0;
163
164	gbeauche	1.1	#ifdef HAVE_MACH_VM
165	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
166			return -1;
167	gbeauche	1.1	#else
168			#ifdef HAVE_MMAP_VM
169	gbeauche	1.4	if (munmap(addr, size) != 0)
170			return -1;
171	gbeauche	1.1	#else
172			free(addr);
173			#endif
174			#endif
175	gbeauche	1.4
176			return 0;
177	gbeauche	1.1	}
178
179			/* Change the memory protection of the region starting at ADDR and
180			extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
181
182			int vm_protect(void * addr, size_t size, int prot)
183			{
184			#ifdef HAVE_MACH_VM
185			int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
186			return ret_code == KERN_SUCCESS ? 0 : -1;
187			#else
188			#ifdef HAVE_MMAP_VM
189			int ret_code = mprotect(addr, size, prot);
190			return ret_code == 0 ? 0 : -1;
191			#else
192			// Unsupported
193			return -1;
194			#endif
195			#endif
196			}
197
198			#ifdef CONFIGURE_TEST_VM_MAP
199			/* Tests covered here:
200			- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
201			- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
202			*/
203			int main(void)
204			{
205			vm_init();
206
207			#define page_align(address) ((char *)((unsigned long)(address) & -page_size))
208			unsigned long page_size = getpagesize();
209
210			const int area_size = 6 * page_size;
211			volatile char * area = (volatile char *) vm_acquire(area_size);
212			volatile char * fault_address = area + (page_size * 7) / 2;
213
214			#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
215			if (area == VM_MAP_FAILED)
216			return 1;
217
218			if (vm_release((char *)area, area_size) < 0)
219			return 1;
220
221			return 0;
222			#endif
223
224			#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
225			if (area == VM_MAP_FAILED)
226			return 0;
227
228			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
229			return 0;
230			#endif
231
232			#if defined(TEST_VM_PROT_RDWR_WRITE)
233			if (area == VM_MAP_FAILED)
234			return 1;
235
236			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
237			return 1;
238
239			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
240			return 1;
241			#endif
242
243			#if defined(TEST_VM_PROT_READ_WRITE)
244			if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
245			return 0;
246			#endif
247
248			#if defined(TEST_VM_PROT_NONE_READ)
249			// this should cause a core dump
250			char foo = *fault_address;
251			return 0;
252			#endif
253
254			#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
255			// this should cause a core dump
256			*fault_address = 'z';
257			return 0;
258			#endif
259
260			#if defined(TEST_VM_PROT_RDWR_WRITE)
261			// this should not cause a core dump
262			*fault_address = 'z';
263			return 0;
264			#endif
265			}
266			#endif