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

/* 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:	1.11
Committed:	2003-12-20T21:44:52Z (20 years, 6 months ago) by gbeauche
Branch:	MAIN
Changes since 1.10:	+2 -2 lines
Log Message:	Fix build with DEC C++ compiler on Tru64.
#	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	gbeauche	1.9	/* 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	gbeauche	1.1	#ifdef HAVE_MMAP_VM
52	gbeauche	1.9	#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	gbeauche	1.1	#ifdef HAVE_MMAP_ANON
62	gbeauche	1.10	#define map_flags (MAP_ANON \| MAP_EXTRA_FLAGS)
63	gbeauche	1.1	#define zero_fd -1
64			#else
65			#ifdef HAVE_MMAP_ANONYMOUS
66	gbeauche	1.10	#define map_flags (MAP_ANONYMOUS \| MAP_EXTRA_FLAGS)
67	gbeauche	1.1	#define zero_fd -1
68			#else
69			#ifdef HAVE_FCNTL_H
70			#include <fcntl.h>
71			#endif
72	gbeauche	1.10	#define map_flags (MAP_EXTRA_FLAGS)
73	gbeauche	1.1	static int zero_fd = -1;
74			#endif
75			#endif
76			#endif
77
78	gbeauche	1.10	/* 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	gbeauche	1.1	/* 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	gbeauche	1.10	void * vm_acquire(size_t size, int options)
126	gbeauche	1.1	{
127			void * addr;
128	gbeauche	1.10
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	gbeauche	1.1	#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	gbeauche	1.10	const int extra_map_flags = translate_map_flags(options);
140
141	gbeauche	1.11	if ((addr = mmap((caddr_t)next_address, size, VM_PAGE_DEFAULT, extra_map_flags \| map_flags, zero_fd, 0)) == (void *)MAP_FAILED)
142	gbeauche	1.1	return VM_MAP_FAILED;
143
144	gbeauche	1.10	// 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	gbeauche	1.3	next_address = (char *)addr + size;
149
150	gbeauche	1.1	// 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	cebix	1.2
162	gbeauche	1.1	// 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	gbeauche	1.10	int vm_acquire_fixed(void * addr, size_t size, int options)
174	gbeauche	1.1	{
175	gbeauche	1.10	// Fixed mappings are required to be private
176			if (options & VM_MAP_SHARED)
177			return -1;
178
179	gbeauche	1.1	#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	gbeauche	1.10	const int extra_map_flags = translate_map_flags(options);
186
187	gbeauche	1.11	if (mmap((caddr_t)addr, size, VM_PAGE_DEFAULT, extra_map_flags \| map_flags \| MAP_FIXED, zero_fd, 0) == (void *)MAP_FAILED)
188	gbeauche	1.1	return -1;
189
190			// Since I don't know the standard behavior of mmap(), zero-fill here
191	gbeauche	1.8	if (memset(addr, 0, size) != addr)
192	gbeauche	1.1	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	gbeauche	1.6	if (vm_protect(addr, size, VM_PAGE_DEFAULT) != 0)
202	gbeauche	1.1	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	gbeauche	1.3	// Safety check: don't try to release memory that was not allocated
213			if (addr == VM_MAP_FAILED)
214			return 0;
215
216	gbeauche	1.1	#ifdef HAVE_MACH_VM
217	gbeauche	1.4	if (vm_deallocate(mach_task_self(), (vm_address_t)addr, size) != KERN_SUCCESS)
218			return -1;
219	gbeauche	1.1	#else
220			#ifdef HAVE_MMAP_VM
221	gbeauche	1.7	if (munmap((caddr_t)addr, size) != 0)
222	gbeauche	1.4	return -1;
223	gbeauche	1.1	#else
224			free(addr);
225			#endif
226			#endif
227	gbeauche	1.4
228			return 0;
229	gbeauche	1.1	}
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	gbeauche	1.7	int ret_code = mprotect((caddr_t)addr, size, prot);
242	gbeauche	1.1	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