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
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
        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:	1.3
Committed:	2001-07-07T09:07:38Z (23 years ago) by gbeauche
Branch:	MAIN
Changes since 1.2:	+8 -1 lines
Log Message:	- Try to map memory contiguously with base addresses returned in increasing order. No host memory region used for Mac emulation (ScratchMem, RAM, ROM, frame buffer) shall be allocated below the RAM space. Actually, MEMBaseDiff should be set to the min(above-mentioned address spaces). ==> Temporary fix for 64-bit addressing systems (e.g. Linux/ia64)
#	Content
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	static char * next_address = 0;
43	#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	if ((addr = mmap(next_address, size, VM_PAGE_DEFAULT, map_flags, zero_fd, 0)) == MAP_FAILED)
100	return VM_MAP_FAILED;
101
102	next_address = (char *)addr + size;
103
104	// 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
116	// 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	// Safety check: don't try to release memory that was not allocated
161	if (addr == VM_MAP_FAILED)
162	return 0;
163
164	#ifdef HAVE_MACH_VM
165	int ret_code = vm_deallocate(mach_task_self(), (vm_address_t)addr, size);
166	return ret_code == KERN_SUCCESS ? 0 : -1;
167	#else
168	#ifdef HAVE_MMAP_VM
169	int ret_code = munmap(addr, size);
170	return ret_code == 0 ? 0 : -1;
171	#else
172	free(addr);
173	return 0;
174	#endif
175	#endif
176	}
177
178	/* Change the memory protection of the region starting at ADDR and
179	extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
180
181	int vm_protect(void * addr, size_t size, int prot)
182	{
183	#ifdef HAVE_MACH_VM
184	int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
185	return ret_code == KERN_SUCCESS ? 0 : -1;
186	#else
187	#ifdef HAVE_MMAP_VM
188	int ret_code = mprotect(addr, size, prot);
189	return ret_code == 0 ? 0 : -1;
190	#else
191	// Unsupported
192	return -1;
193	#endif
194	#endif
195	}
196
197	#ifdef CONFIGURE_TEST_VM_MAP
198	/* Tests covered here:
199	- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
200	- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
201	*/
202	int main(void)
203	{
204	vm_init();
205
206	#define page_align(address) ((char *)((unsigned long)(address) & -page_size))
207	unsigned long page_size = getpagesize();
208
209	const int area_size = 6 * page_size;
210	volatile char * area = (volatile char *) vm_acquire(area_size);
211	volatile char * fault_address = area + (page_size * 7) / 2;
212
213	#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
214	if (area == VM_MAP_FAILED)
215	return 1;
216
217	if (vm_release((char *)area, area_size) < 0)
218	return 1;
219
220	return 0;
221	#endif
222
223	#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
224	if (area == VM_MAP_FAILED)
225	return 0;
226
227	if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
228	return 0;
229	#endif
230
231	#if defined(TEST_VM_PROT_RDWR_WRITE)
232	if (area == VM_MAP_FAILED)
233	return 1;
234
235	if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
236	return 1;
237
238	if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
239	return 1;
240	#endif
241
242	#if defined(TEST_VM_PROT_READ_WRITE)
243	if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
244	return 0;
245	#endif
246
247	#if defined(TEST_VM_PROT_NONE_READ)
248	// this should cause a core dump
249	char foo = *fault_address;
250	return 0;
251	#endif
252
253	#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
254	// this should cause a core dump
255	*fault_address = 'z';
256	return 0;
257	#endif
258
259	#if defined(TEST_VM_PROT_RDWR_WRITE)
260	// this should not cause a core dump
261	*fault_address = 'z';
262	return 0;
263	#endif
264	}
265	#endif