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(addr, 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(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(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:	1.6
Committed:	2002-02-11T14:28:02Z (22 years, 9 months ago) by gbeauche
Branch:	MAIN
Changes since 1.5:	+2 -2 lines
Log Message:	- vm_acquire_fixed: Fix memset() and vm_protect() calls so that the address is really the one specified instead of always zero.
#	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) 1997-2002 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(addr, 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(addr, 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	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
166	return -1;
167	#else
168	#ifdef HAVE_MMAP_VM
169	if (munmap(addr, size) != 0)
170	return -1;
171	#else
172	free(addr);
173	#endif
174	#endif
175
176	return 0;
177	}
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