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) 1997-2004 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

/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII
   because the emulated target is 32-bit and this helps to allocate
   memory so that branches could be resolved more easily (32-bit
   displacement to code in .text), on AMD64 for example.  */
#ifndef MAP_32BIT
#define MAP_32BIT 0
#endif

#define MAP_EXTRA_FLAGS (MAP_32BIT)

#ifdef HAVE_MMAP_VM
#if defined(__linux__) && defined(__i386__)
/* Force a reasonnable address below 0x80000000 on x86 so that we
   don't get addresses above when the program is run on AMD64.
   NOTE: this is empirically determined on Linux/x86.  */
#define MAP_BASE        0x10000000
#else
#define MAP_BASE        0x00000000
#endif
static char * next_address = (char *)MAP_BASE;
#ifdef HAVE_MMAP_ANON
#define map_flags       (MAP_ANON | MAP_EXTRA_FLAGS)
#define zero_fd         -1
#else
#ifdef HAVE_MMAP_ANONYMOUS
#define map_flags       (MAP_ANONYMOUS | MAP_EXTRA_FLAGS)
#define zero_fd         -1
#else
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#define map_flags       (MAP_EXTRA_FLAGS)
static int zero_fd      = -1;
#endif
#endif
#endif

/* Translate generic VM map flags to host values.  */

#ifdef HAVE_MMAP_VM
static int translate_map_flags(int vm_flags)
{
        int flags = 0;
        if (vm_flags & VM_MAP_SHARED)
                flags |= MAP_SHARED;
        if (vm_flags & VM_MAP_PRIVATE)
                flags |= MAP_PRIVATE;
        if (vm_flags & VM_MAP_FIXED)
                flags |= MAP_FIXED;
        if (vm_flags & VM_MAP_32BIT)
                flags |= MAP_32BIT;
        return flags;
}
#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, int options)
{
        void * addr;

        // VM_MAP_FIXED are to be used with vm_acquire_fixed() only
        if (options & VM_MAP_FIXED)
                return VM_MAP_FAILED;

#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
        const int extra_map_flags = translate_map_flags(options);

        if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, extra_map_flags | map_flags, zero_fd, 0)) == (void *)MAP_FAILED)
                return VM_MAP_FAILED;
        
        // Sanity checks for 64-bit platforms
        if (sizeof(void *) == 8 && (options & VM_MAP_32BIT) && !((char *)addr <= (char *)0xffffffff))
                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, int options)
{
        // Fixed mappings are required to be private
        if (options & VM_MAP_SHARED)
                return -1;

#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
        const int extra_map_flags = translate_map_flags(options);

        if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, extra_map_flags | map_flags | MAP_FIXED, zero_fd, 0) == (void *)MAP_FAILED)
                return -1;
        
        // Since I don't know the standard behavior of mmap(), zero-fill here
        if (memset(addr, 0, size) != addr)
                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((caddr_t)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((caddr_t)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:	1.12
Committed:	2004-01-12T15:29:25Z (20 years, 10 months ago) by cebix
Branch:	MAIN
CVS Tags:	nigel-build-16, nigel-build-15
Changes since 1.11:	+1 -1 lines
Log Message:	Happy New Year! :)
#	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) 1997-2004 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	/* We want MAP_32BIT, if available, for SheepShaver and BasiliskII
42	because the emulated target is 32-bit and this helps to allocate
43	memory so that branches could be resolved more easily (32-bit
44	displacement to code in .text), on AMD64 for example. */
45	#ifndef MAP_32BIT
46	#define MAP_32BIT 0
47	#endif
48
49	#define MAP_EXTRA_FLAGS (MAP_32BIT)
50
51	#ifdef HAVE_MMAP_VM
52	#if defined(__linux__) && defined(__i386__)
53	/* Force a reasonnable address below 0x80000000 on x86 so that we
54	don't get addresses above when the program is run on AMD64.
55	NOTE: this is empirically determined on Linux/x86. */
56	#define MAP_BASE 0x10000000
57	#else
58	#define MAP_BASE 0x00000000
59	#endif
60	static char * next_address = (char *)MAP_BASE;
61	#ifdef HAVE_MMAP_ANON
62	#define map_flags (MAP_ANON \| MAP_EXTRA_FLAGS)
63	#define zero_fd -1
64	#else
65	#ifdef HAVE_MMAP_ANONYMOUS
66	#define map_flags (MAP_ANONYMOUS \| MAP_EXTRA_FLAGS)
67	#define zero_fd -1
68	#else
69	#ifdef HAVE_FCNTL_H
70	#include <fcntl.h>
71	#endif
72	#define map_flags (MAP_EXTRA_FLAGS)
73	static int zero_fd = -1;
74	#endif
75	#endif
76	#endif
77
78	/* Translate generic VM map flags to host values. */
79
80	#ifdef HAVE_MMAP_VM
81	static int translate_map_flags(int vm_flags)
82	{
83	int flags = 0;
84	if (vm_flags & VM_MAP_SHARED)
85	flags \|= MAP_SHARED;
86	if (vm_flags & VM_MAP_PRIVATE)
87	flags \|= MAP_PRIVATE;
88	if (vm_flags & VM_MAP_FIXED)
89	flags \|= MAP_FIXED;
90	if (vm_flags & VM_MAP_32BIT)
91	flags \|= MAP_32BIT;
92	return flags;
93	}
94	#endif
95
96	/* Initialize the VM system. Returns 0 if successful, -1 for errors. */
97
98	int vm_init(void)
99	{
100	#ifdef HAVE_MMAP_VM
101	#ifndef zero_fd
102	zero_fd = open("/dev/zero", O_RDWR);
103	if (zero_fd < 0)
104	return -1;
105	#endif
106	#endif
107	return 0;
108	}
109
110	/* Deallocate all internal data used to wrap virtual memory allocators. */
111
112	void vm_exit(void)
113	{
114	#ifdef HAVE_MMAP_VM
115	#ifndef zero_fd
116	close(zero_fd);
117	#endif
118	#endif
119	}
120
121	/* Allocate zero-filled memory of SIZE bytes. The mapping is private
122	and default protection bits are read / write. The return value
123	is the actual mapping address chosen or VM_MAP_FAILED for errors. */
124
125	void * vm_acquire(size_t size, int options)
126	{
127	void * addr;
128
129	// VM_MAP_FIXED are to be used with vm_acquire_fixed() only
130	if (options & VM_MAP_FIXED)
131	return VM_MAP_FAILED;
132
133	#ifdef HAVE_MACH_VM
134	// vm_allocate() returns a zero-filled memory region
135	if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, TRUE) != KERN_SUCCESS)
136	return VM_MAP_FAILED;
137	#else
138	#ifdef HAVE_MMAP_VM
139	const int extra_map_flags = translate_map_flags(options);
140
141	if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, extra_map_flags \| map_flags, zero_fd, 0)) == (void *)MAP_FAILED)
142	return VM_MAP_FAILED;
143
144	// Sanity checks for 64-bit platforms
145	if (sizeof(void ) == 8 && (options & VM_MAP_32BIT) && !((char )addr <= (char *)0xffffffff))
146	return VM_MAP_FAILED;
147
148	next_address = (char *)addr + size;
149
150	// Since I don't know the standard behavior of mmap(), zero-fill here
151	if (memset(addr, 0, size) != addr)
152	return VM_MAP_FAILED;
153	#else
154	if ((addr = calloc(size, 1)) == 0)
155	return VM_MAP_FAILED;
156
157	// Omit changes for protections because they are not supported in this mode
158	return addr;
159	#endif
160	#endif
161
162	// Explicitely protect the newly mapped region here because on some systems,
163	// say MacOS X, mmap() doesn't honour the requested protection flags.
164	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
165	return VM_MAP_FAILED;
166
167	return addr;
168	}
169
170	/* Allocate zero-filled memory at exactly ADDR (which must be page-aligned).
171	Retuns 0 if successful, -1 on errors. */
172
173	int vm_acquire_fixed(void * addr, size_t size, int options)
174	{
175	// Fixed mappings are required to be private
176	if (options & VM_MAP_SHARED)
177	return -1;
178
179	#ifdef HAVE_MACH_VM
180	// vm_allocate() returns a zero-filled memory region
181	if (vm_allocate(mach_task_self(), (vm_address_t *)&addr, size, 0) != KERN_SUCCESS)
182	return -1;
183	#else
184	#ifdef HAVE_MMAP_VM
185	const int extra_map_flags = translate_map_flags(options);
186
187	if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, extra_map_flags \| map_flags \| MAP_FIXED, zero_fd, 0) == (void *)MAP_FAILED)
188	return -1;
189
190	// Since I don't know the standard behavior of mmap(), zero-fill here
191	if (memset(addr, 0, size) != addr)
192	return -1;
193	#else
194	// Unsupported
195	return -1;
196	#endif
197	#endif
198
199	// Explicitely protect the newly mapped region here because on some systems,
200	// say MacOS X, mmap() doesn't honour the requested protection flags.
201	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
202	return -1;
203
204	return 0;
205	}
206
207	/* Deallocate any mapping for the region starting at ADDR and extending
208	LEN bytes. Returns 0 if successful, -1 on errors. */
209
210	int vm_release(void * addr, size_t size)
211	{
212	// Safety check: don't try to release memory that was not allocated
213	if (addr == VM_MAP_FAILED)
214	return 0;
215
216	#ifdef HAVE_MACH_VM
217	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
218	return -1;
219	#else
220	#ifdef HAVE_MMAP_VM
221	if (munmap((caddr_t)addr, size) != 0)
222	return -1;
223	#else
224	free(addr);
225	#endif
226	#endif
227
228	return 0;
229	}
230
231	/* Change the memory protection of the region starting at ADDR and
232	extending LEN bytes to PROT. Returns 0 if successful, -1 for errors. */
233
234	int vm_protect(void * addr, size_t size, int prot)
235	{
236	#ifdef HAVE_MACH_VM
237	int ret_code = vm_protect(mach_task_self(), (vm_address_t)addr, size, 0, prot);
238	return ret_code == KERN_SUCCESS ? 0 : -1;
239	#else
240	#ifdef HAVE_MMAP_VM
241	int ret_code = mprotect((caddr_t)addr, size, prot);
242	return ret_code == 0 ? 0 : -1;
243	#else
244	// Unsupported
245	return -1;
246	#endif
247	#endif
248	}
249
250	#ifdef CONFIGURE_TEST_VM_MAP
251	/* Tests covered here:
252	- TEST_VM_PROT_* program slices actually succeeds when a crash occurs
253	- TEST_VM_MAP_ANON* program slices succeeds when it could be compiled
254	*/
255	int main(void)
256	{
257	vm_init();
258
259	#define page_align(address) ((char *)((unsigned long)(address) & -page_size))
260	unsigned long page_size = getpagesize();
261
262	const int area_size = 6 * page_size;
263	volatile char * area = (volatile char *) vm_acquire(area_size);
264	volatile char * fault_address = area + (page_size * 7) / 2;
265
266	#if defined(TEST_VM_MMAP_ANON) \|\| defined(TEST_VM_MMAP_ANONYMOUS)
267	if (area == VM_MAP_FAILED)
268	return 1;
269
270	if (vm_release((char *)area, area_size) < 0)
271	return 1;
272
273	return 0;
274	#endif
275
276	#if defined(TEST_VM_PROT_NONE_READ) \|\| defined(TEST_VM_PROT_NONE_WRITE)
277	if (area == VM_MAP_FAILED)
278	return 0;
279
280	if (vm_protect(page_align(fault_address), page_size, VM_PAGE_NOACCESS) < 0)
281	return 0;
282	#endif
283
284	#if defined(TEST_VM_PROT_RDWR_WRITE)
285	if (area == VM_MAP_FAILED)
286	return 1;
287
288	if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
289	return 1;
290
291	if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ \| VM_PAGE_WRITE) < 0)
292	return 1;
293	#endif
294
295	#if defined(TEST_VM_PROT_READ_WRITE)
296	if (vm_protect(page_align(fault_address), page_size, VM_PAGE_READ) < 0)
297	return 0;
298	#endif
299
300	#if defined(TEST_VM_PROT_NONE_READ)
301	// this should cause a core dump
302	char foo = *fault_address;
303	return 0;
304	#endif
305
306	#if defined(TEST_VM_PROT_NONE_WRITE) \|\| defined(TEST_VM_PROT_READ_WRITE)
307	// this should cause a core dump
308	*fault_address = 'z';
309	return 0;
310	#endif
311
312	#if defined(TEST_VM_PROT_RDWR_WRITE)
313	// this should not cause a core dump
314	*fault_address = 'z';
315	return 0;
316	#endif
317	}
318	#endif