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
#	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	#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