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newlib/winsup/cygwin/mmap.cc

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/* mmap.cc
Copyright 1996, 1997, 1998, 2000, 2001 Cygnus Solutions.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include <unistd.h>
#include <stdlib.h>
#include <stddef.h>
#include <sys/mman.h>
#include <errno.h>
#include "fhandler.h"
#include "dtable.h"
#include "cygerrno.h"
#include "sync.h"
#include "sigproc.h"
#include "pinfo.h"
#include "security.h"
#define PAGE_CNT(bytes) howmany(bytes,getpagesize())
#define PGBITS (sizeof(DWORD)*8)
#define MAPSIZE(pages) howmany(pages,PGBITS)
#define MAP_SET(n) (map_map_[(n)/PGBITS] |= (1L << ((n) % PGBITS)))
#define MAP_CLR(n) (map_map_[(n)/PGBITS] &= ~(1L << ((n) % PGBITS)))
#define MAP_ISSET(n) (map_map_[(n)/PGBITS] & (1L << ((n) % PGBITS)))
/*
* Simple class used to keep a record of all current
* mmap areas in a process. Needed so that
* they can be duplicated after a fork().
*/
class mmap_record
{
private:
int fdesc_;
HANDLE mapping_handle_;
DWORD access_mode_;
DWORD offset_;
DWORD size_to_map_;
caddr_t base_address_;
DWORD *map_map_;
public:
mmap_record (int fd, HANDLE h, DWORD ac, DWORD o, DWORD s, caddr_t b) :
fdesc_ (fd), mapping_handle_ (h), access_mode_ (ac), offset_ (o),
size_to_map_ (s), base_address_ (b) , map_map_ (NULL) { ; }
/* Default Copy constructor/operator=/destructor are ok */
/* Simple accessors */
int get_fd () const { return fdesc_; }
HANDLE get_handle () const { return mapping_handle_; }
DWORD get_access () const { return access_mode_; }
DWORD get_offset () const { return offset_; }
DWORD get_size () const { return size_to_map_; }
caddr_t get_address () const { return base_address_; }
DWORD *get_map () const { return map_map_; }
void alloc_map ()
{
/* Allocate one bit per page */
map_map_ = (DWORD *) calloc (MAPSIZE(PAGE_CNT (size_to_map_)),
sizeof (DWORD));
if (os_being_run == winNT)
{
DWORD old_prot;
if (!VirtualProtect (base_address_, size_to_map_,
PAGE_NOACCESS, &old_prot))
syscall_printf ("-1 = alloc_map (): %E");
}
}
void free_map () { if (map_map_) free (map_map_); }
DWORD find_empty (DWORD pages);
DWORD map_map (DWORD off, DWORD len);
BOOL unmap_map (caddr_t addr, DWORD len);
void fixup_map (void);
};
DWORD
mmap_record::find_empty (DWORD pages)
{
DWORD mapped_pages = PAGE_CNT (size_to_map_);
DWORD start;
for (start = 0; start <= mapped_pages - pages; ++start)
if (!MAP_ISSET (start))
{
DWORD cnt;
for (cnt = 0; cnt < pages; ++cnt)
if (MAP_ISSET (start + cnt))
break;
if (cnt >= pages)
return start;
}
return (DWORD)-1;
}
DWORD
mmap_record::map_map (DWORD off, DWORD len)
{
DWORD prot, old_prot;
switch (access_mode_)
{
case FILE_MAP_WRITE:
prot = PAGE_READWRITE;
break;
case FILE_MAP_READ:
prot = PAGE_READONLY;
break;
default:
prot = PAGE_WRITECOPY;
break;
}
len = PAGE_CNT (len);
if (fdesc_ == -1 && !off)
{
off = find_empty (len);
if (off != (DWORD)-1)
{
if (os_being_run == winNT
&& !VirtualProtect (base_address_ + off * getpagesize (),
len * getpagesize (), prot, &old_prot))
syscall_printf ("-1 = map_map (): %E");
while (len-- > 0)
MAP_SET (off + len);
return off * getpagesize ();
}
return 0L;
}
off -= offset_;
DWORD start = off / getpagesize ();
if (os_being_run == winNT
&& !VirtualProtect (base_address_ + start * getpagesize (),
len * getpagesize (), prot, &old_prot))
syscall_printf ("-1 = map_map (): %E");
for (; len-- > 0; ++start)
MAP_SET (start);
return off;
}
BOOL
mmap_record::unmap_map (caddr_t addr, DWORD len)
{
DWORD old_prot;
DWORD off = addr - base_address_;
off /= getpagesize ();
len = PAGE_CNT (len);
if (os_being_run == winNT
&& !VirtualProtect (base_address_ + off * getpagesize (),
len * getpagesize (), PAGE_NOACCESS, &old_prot))
syscall_printf ("-1 = unmap_map (): %E");
for (; len-- > 0; ++off)
MAP_CLR (off);
/* Return TRUE if all pages are free'd which may result in unmapping
the whole chunk. */
for (len = MAPSIZE(PAGE_CNT (size_to_map_)); len > 0; )
if (map_map_[--len])
return FALSE;
return TRUE;
}
void
mmap_record::fixup_map ()
{
if (os_being_run != winNT)
return;
DWORD prot, old_prot;
switch (access_mode_)
{
case FILE_MAP_WRITE:
prot = PAGE_READWRITE;
break;
case FILE_MAP_READ:
prot = PAGE_READONLY;
break;
default:
prot = PAGE_WRITECOPY;
break;
}
for (DWORD off = PAGE_CNT (size_to_map_); off > 0; --off)
VirtualProtect (base_address_ + off * getpagesize (),
getpagesize (),
MAP_ISSET (off - 1) ? prot : PAGE_NOACCESS,
&old_prot);
}
class list {
public:
mmap_record *recs;
int nrecs, maxrecs;
int fd;
DWORD hash;
list ();
~list ();
mmap_record *add_record (mmap_record r);
void erase (int i);
mmap_record *match (DWORD off, DWORD len);
off_t match (caddr_t addr, DWORD len, off_t start);
};
list::list ()
: nrecs (0), maxrecs (10), fd (0), hash (0)
{
recs = (mmap_record *) malloc (10 * sizeof(mmap_record));
}
list::~list ()
{
for (mmap_record *rec = recs; nrecs-- > 0; ++rec)
rec->free_map ();
free (recs);
}
mmap_record *
list::add_record (mmap_record r)
{
if (nrecs == maxrecs)
{
maxrecs += 5;
recs = (mmap_record *) realloc (recs, maxrecs * sizeof (mmap_record));
}
recs[nrecs] = r;
recs[nrecs].alloc_map ();
return recs + nrecs++;
}
/* Used in mmap() */
mmap_record *
list::match (DWORD off, DWORD len)
{
if (fd == -1 && !off)
{
len = PAGE_CNT (len);
for (int i = 0; i < nrecs; ++i)
if (recs[i].find_empty (len) != (DWORD)-1)
return recs + i;
}
else
{
for (int i = 0; i < nrecs; ++i)
if (off >= recs[i].get_offset ()
&& off + len <= recs[i].get_offset () + recs[i].get_size ())
return recs + i;
}
return NULL;
}
/* Used in munmap() */
off_t
list::match (caddr_t addr, DWORD len, off_t start)
{
for (int i = start + 1; i < nrecs; ++i)
if (addr >= recs[i].get_address ()
&& addr + len <= recs[i].get_address () + recs[i].get_size ())
return i;
return (off_t)-1;
}
void
list::erase (int i)
{
recs[i].free_map ();
for (; i < nrecs-1; i++)
recs[i] = recs[i+1];
nrecs--;
}
class map {
public:
list **lists;
int nlists, maxlists;
map ();
~map ();
list *get_list_by_fd (int fd);
list *add_list (list *l, int fd);
void erase (int i);
};
map::map ()
{
lists = (list **) malloc (10 * sizeof(list *));
nlists = 0;
maxlists = 10;
}
map::~map ()
{
free (lists);
}
list *
map::get_list_by_fd (int fd)
{
int i;
for (i=0; i<nlists; i++)
#if 0 /* The fd isn't sufficient since it could already be another file. */
if (lists[i]->fd == fd
#else /* so we use the name hash value to identify the file unless
it's not an anonymous mapping. */
if ((fd == -1 && lists[i]->fd == -1)
|| lists[i]->hash == fdtab[fd]->get_namehash ())
#endif
return lists[i];
return 0;
}
list *
map::add_list (list *l, int fd)
{
l->fd = fd;
if (fd != -1)
l->hash = fdtab[fd]->get_namehash ();
if (nlists == maxlists)
{
maxlists += 5;
lists = (list **) realloc (lists, maxlists * sizeof (list *));
}
lists[nlists++] = l;
return lists[nlists-1];
}
void
map::erase (int i)
{
for (; i < nlists-1; i++)
lists[i] = lists[i+1];
nlists--;
}
/*
* Code to keep a record of all mmap'ed areas in a process.
* Needed to duplicate tham in a child of fork().
* mmap_record classes are kept in an STL list in an STL map, keyed
* by file descriptor. This is *NOT* duplicated accross a fork(), it
* needs to be specially handled by the fork code.
*/
static map *mmapped_areas;
extern "C"
caddr_t
mmap (caddr_t addr, size_t len, int prot, int flags, int fd, off_t off)
{
syscall_printf ("addr %x, len %d, prot %x, flags %x, fd %d, off %d",
addr, len, prot, flags, fd, off);
static DWORD granularity;
if (!granularity)
{
SYSTEM_INFO si;
GetSystemInfo (&si);
granularity = si.dwAllocationGranularity;
}
/* Error conditions according to SUSv2 */
if (off % getpagesize ()
|| (!(flags & MAP_SHARED) && !(flags & MAP_PRIVATE))
|| ((flags & MAP_SHARED) && (flags & MAP_PRIVATE))
|| ((flags & MAP_FIXED) && ((DWORD)addr % granularity))
|| !len)
{
set_errno (EINVAL);
syscall_printf ("-1 = mmap(): EINVAL");
return MAP_FAILED;
}
DWORD access = (prot & PROT_WRITE) ? FILE_MAP_WRITE : FILE_MAP_READ;
if (flags & MAP_PRIVATE)
access = FILE_MAP_COPY;
SetResourceLock(LOCK_MMAP_LIST,READ_LOCK|WRITE_LOCK," mmap");
#if 0
/* Windows 95 does not have fixed addresses */
/*
* CV: This assumption isn't correct. See Microsoft Platform SDK, Memory,
* description of call `MapViewOfFileEx'.
*/
if ((os_being_run != winNT) && (flags & MAP_FIXED))
{
set_errno (EINVAL);
syscall_printf ("-1 = mmap(): win95 and MAP_FIXED");
return MAP_FAILED;
}
#endif
if (mmapped_areas == NULL)
{
/* First mmap call, create STL map */
mmapped_areas = new map;
if (mmapped_areas == NULL)
{
set_errno (ENOMEM);
syscall_printf ("-1 = mmap(): ENOMEM");
ReleaseResourceLock(LOCK_MMAP_LIST,READ_LOCK|WRITE_LOCK," mmap");
return MAP_FAILED;
}
}
if (flags & MAP_ANONYMOUS)
fd = -1;
/* Map always in multipliers of `granularity'-sized chunks. */
DWORD gran_off = off & ~(granularity - 1);
DWORD gran_len = howmany (len, granularity) * granularity;
fhandler_disk_file fh_paging_file (NULL);
fhandler_base *fh = NULL;
caddr_t base = addr;
HANDLE h;
if (fd != -1)
{
/* Ensure that fd is open */
if (fdtab.not_open (fd))
{
set_errno (EBADF);
syscall_printf ("-1 = mmap(): EBADF");
ReleaseResourceLock(LOCK_MMAP_LIST,READ_LOCK|WRITE_LOCK," mmap");
return MAP_FAILED;
}
fh = fdtab[fd];
if (fh->get_device () == FH_DISK)
{
DWORD fsiz = GetFileSize (fh->get_handle (), NULL);
fsiz -= gran_off;
if (gran_len > fsiz)
gran_len = fsiz;
}
else if (fh->get_device () == FH_ZERO)
/* mmap /dev/zero is like MAP_ANONYMOUS. */
fd = -1;
}
if (fd == -1)
{
fh_paging_file.set_io_handle (INVALID_HANDLE_VALUE);
fh = &fh_paging_file;
}
list *l = mmapped_areas->get_list_by_fd (fd);
/* First check if this mapping matches into the chunk of another
already performed mapping. Only valid for MAP_SHARED and for
MAP_ANON in a special case of MAP_PRIVATE. */
if (l && ((flags & MAP_SHARED) || (fd == -1 && off == 0)))
{
mmap_record *rec;
if ((rec = l->match (off, len)) != NULL)
{
off = rec->map_map (off, len);
caddr_t ret = rec->get_address () + off;
syscall_printf ("%x = mmap() succeeded", ret);
ReleaseResourceLock(LOCK_MMAP_LIST,READ_LOCK|WRITE_LOCK," mmap");
return ret;
}
}
h = fh->mmap (&base, gran_len, access, flags, gran_off);
if (h == INVALID_HANDLE_VALUE)
{
ReleaseResourceLock(LOCK_MMAP_LIST,READ_LOCK|WRITE_LOCK," mmap");
return MAP_FAILED;
}
/* Now we should have a successfully mmapped area.
Need to save it so forked children can reproduce it.
*/
if (fd == -1)
gran_len = PAGE_CNT (gran_len) * getpagesize ();
mmap_record mmap_rec (fd, h, access, gran_off, gran_len, base);
/* Get list of mmapped areas for this fd, create a new one if
one does not exist yet.
*/
if (l == 0)
{
/* Create a new one */
l = new list;
if (l == 0)
{
fh->munmap (h, base, gran_len);
set_errno (ENOMEM);
syscall_printf ("-1 = mmap(): ENOMEM");
ReleaseResourceLock(LOCK_MMAP_LIST,READ_LOCK|WRITE_LOCK," mmap");
return MAP_FAILED;
}
l = mmapped_areas->add_list (l, fd);
}
/* Insert into the list */
mmap_record *rec = l->add_record (mmap_rec);
off = rec->map_map (off, len);
caddr_t ret = rec->get_address () + off;
syscall_printf ("%x = mmap() succeeded", ret);
ReleaseResourceLock(LOCK_MMAP_LIST,READ_LOCK|WRITE_LOCK," mmap");
return ret;
}
/* munmap () removes an mmapped area. It insists that base area
requested is the same as that mmapped, error if not. */
extern "C"
int
munmap (caddr_t addr, size_t len)
{
syscall_printf ("munmap (addr %x, len %d)", addr, len);
/* Error conditions according to SUSv2 */
if (((DWORD)addr % getpagesize ()) || !len)
{
set_errno (EINVAL);
syscall_printf ("-1 = munmap(): Invalid parameters");
return -1;
}
SetResourceLock(LOCK_MMAP_LIST,WRITE_LOCK|READ_LOCK," munmap");
/* Check if a mmap'ed area was ever created */
if (mmapped_areas == NULL)
{
syscall_printf ("-1 = munmap(): mmapped_areas == NULL");
set_errno (EINVAL);
ReleaseResourceLock(LOCK_MMAP_LIST,WRITE_LOCK|READ_LOCK," munmap");
return -1;
}
/* Iterate through the map, looking for the mmapped area.
Error if not found. */
for (int it = 0; it < mmapped_areas->nlists; ++it)
{
list *l = mmapped_areas->lists[it];
if (l != 0)
{
int fd = l->fd;
fhandler_disk_file fh_paging_file (NULL);
fhandler_base *fh;
if (fd == -1 || fdtab.not_open (fd))
{
fh_paging_file.set_io_handle (INVALID_HANDLE_VALUE);
fh = &fh_paging_file;
}
else
fh = fdtab[fd];
off_t li = -1;
if ((li = l->match(addr, len, li)) >= 0)
{
mmap_record *rec = l->recs + li;
if (rec->unmap_map (addr, len))
{
fh->munmap (rec->get_handle (), addr, len);
/* Delete the entry. */
l->erase (li);
}
syscall_printf ("0 = munmap(): %x", addr);
ReleaseResourceLock(LOCK_MMAP_LIST,WRITE_LOCK|READ_LOCK," munmap");
return 0;
}
}
}
set_errno (EINVAL);
syscall_printf ("-1 = munmap(): EINVAL");
ReleaseResourceLock(LOCK_MMAP_LIST,WRITE_LOCK|READ_LOCK," munmap");
return -1;
}
/* Sync file with memory. Ignore flags for now. */
extern "C"
int
msync (caddr_t addr, size_t len, int flags)
{
syscall_printf ("addr = %x, len = %d, flags = %x",
addr, len, flags);
/* However, check flags for validity. */
if ((flags & ~(MS_ASYNC | MS_SYNC | MS_INVALIDATE))
|| ((flags & MS_ASYNC) && (flags & MS_SYNC)))
{
syscall_printf ("-1 = msync(): Invalid flags");
set_errno (EINVAL);
return -1;
}
SetResourceLock(LOCK_MMAP_LIST,WRITE_LOCK|READ_LOCK," msync");
/* Check if a mmap'ed area was ever created */
if (mmapped_areas == NULL)
{
syscall_printf ("-1 = msync(): mmapped_areas == NULL");
set_errno (EINVAL);
ReleaseResourceLock(LOCK_MMAP_LIST,WRITE_LOCK|READ_LOCK," msync");
return -1;
}
/* Iterate through the map, looking for the mmapped area.
Error if not found. */
for (int it = 0; it < mmapped_areas->nlists; ++it)
{
list *l = mmapped_areas->lists[it];
if (l != 0)
{
int fd = l->fd;
fhandler_disk_file fh_paging_file (NULL);
fhandler_base *fh;
if (fd == -1 || fdtab.not_open (fd))
{
fh_paging_file.set_io_handle (INVALID_HANDLE_VALUE);
fh = &fh_paging_file;
}
else
fh = fdtab[fd];
for (int li = 0; li < l->nrecs; ++li)
{
mmap_record *rec = l->recs + li;
if (rec->get_address () == addr)
{
int ret = fh->msync (rec->get_handle (), addr, len, flags);
if (ret)
syscall_printf ("%d = msync(): %E", ret);
else
syscall_printf ("0 = msync()");
ReleaseResourceLock(LOCK_MMAP_LIST,WRITE_LOCK|READ_LOCK," msync");
return 0;
}
}
}
}
/* SUSv2: Return code if indicated memory was not mapped is ENOMEM. */
set_errno (ENOMEM);
syscall_printf ("-1 = msync(): ENOMEM");
ReleaseResourceLock(LOCK_MMAP_LIST,WRITE_LOCK|READ_LOCK," msync");
return -1;
}
/*
* Base implementation:
*
* `mmap' returns ENODEV as documented in SUSv2.
* In contrast to the global function implementation, the member function
* `mmap' has to return the mapped base address in `addr' and the handle to
* the mapping object as return value. In case of failure, the fhandler
* mmap has to close that handle by itself and return INVALID_HANDLE_VALUE.
*
* `munmap' and `msync' get the handle to the mapping object as first parameter
* additionally.
*/
HANDLE
fhandler_base::mmap (caddr_t *addr, size_t len, DWORD access,
int flags, off_t off)
{
set_errno (ENODEV);
return INVALID_HANDLE_VALUE;
}
int
fhandler_base::munmap (HANDLE h, caddr_t addr, size_t len)
{
set_errno (ENODEV);
return -1;
}
int
fhandler_base::msync (HANDLE h, caddr_t addr, size_t len, int flags)
{
set_errno (ENODEV);
return -1;
}
BOOL
fhandler_base::fixup_mmap_after_fork (HANDLE h, DWORD access, DWORD offset,
DWORD size, void *address)
{
set_errno (ENODEV);
return -1;
}
/* Implementation for disk files. */
HANDLE
fhandler_disk_file::mmap (caddr_t *addr, size_t len, DWORD access,
int flags, off_t off)
{
DWORD protect;
if (access & FILE_MAP_COPY)
protect = PAGE_WRITECOPY;
else if (access & FILE_MAP_WRITE)
protect = PAGE_READWRITE;
else
protect = PAGE_READONLY;
HANDLE h = CreateFileMapping (get_handle (),
&sec_none,
protect,
0,
get_handle () == INVALID_HANDLE_VALUE ? len : 0,
NULL);
if (h == 0)
{
__seterrno ();
syscall_printf ("-1 = mmap(): CreateFileMapping failed with %E");
return INVALID_HANDLE_VALUE;
}
void *base = MapViewOfFileEx (h, access, 0, off, len,
(flags & MAP_FIXED) ? *addr : NULL);
if (!base || ((flags & MAP_FIXED) && base != *addr))
{
if (!base)
{
__seterrno ();
syscall_printf ("-1 = mmap(): MapViewOfFileEx failed with %E");
}
else
{
set_errno (EINVAL);
syscall_printf ("-1 = mmap(): address shift with MAP_FIXED given");
}
CloseHandle (h);
return INVALID_HANDLE_VALUE;
}
*addr = (caddr_t) base;
return h;
}
int
fhandler_disk_file::munmap (HANDLE h, caddr_t addr, size_t len)
{
UnmapViewOfFile (addr);
CloseHandle (h);
return 0;
}
int
fhandler_disk_file::msync (HANDLE h, caddr_t addr, size_t len, int flags)
{
if (FlushViewOfFile (addr, len) == 0)
{
__seterrno ();
return -1;
}
return 0;
}
BOOL
fhandler_disk_file::fixup_mmap_after_fork (HANDLE h, DWORD access, DWORD offset,
DWORD size, void *address)
{
/* Re-create the MapViewOfFileEx call */
void *base = MapViewOfFileEx (h, access, 0, offset, size, address);
return base == address;
}
/* Set memory protection */
extern "C"
int
mprotect (caddr_t addr, size_t len, int prot)
{
DWORD old_prot;
DWORD new_prot = 0;
syscall_printf ("mprotect (addr %x, len %d, prot %x)", addr, len, prot);
if (prot == PROT_NONE)
new_prot = PAGE_NOACCESS;
else
{
switch (prot)
{
case PROT_READ | PROT_WRITE | PROT_EXEC:
new_prot = PAGE_EXECUTE_READWRITE;
break;
case PROT_READ | PROT_WRITE:
new_prot = PAGE_READWRITE;
break;
case PROT_READ | PROT_EXEC:
new_prot = PAGE_EXECUTE_READ;
break;
case PROT_READ:
new_prot = PAGE_READONLY;
break;
default:
syscall_printf ("-1 = mprotect (): invalid prot value");
set_errno (EINVAL);
return -1;
}
}
if (VirtualProtect (addr, len, new_prot, &old_prot) == 0)
{
__seterrno ();
syscall_printf ("-1 = mprotect (): %E");
return -1;
}
syscall_printf ("0 = mprotect ()");
return 0;
}
/*
* Call to re-create all the file mappings in a forked
* child. Called from the child in initialization. At this
* point we are passed a valid mmapped_areas map, and all the
* HANDLE's are valid for the child, but none of the
* mapped areas are in our address space. We need to iterate
* through the map, doing the MapViewOfFile calls.
*/
int __stdcall
fixup_mmaps_after_fork ()
{
debug_printf ("recreate_mmaps_after_fork, mmapped_areas %p", mmapped_areas);
/* Check if a mmapped area was ever created */
if (mmapped_areas == NULL)
return 0;
/* Iterate through the map */
for (int it = 0; it < mmapped_areas->nlists; ++it)
{
list *l = mmapped_areas->lists[it];
if (l != 0)
{
int li;
for (li = 0; li < l->nrecs; ++li)
{
mmap_record *rec = l->recs + li;
debug_printf ("fd %d, h %x, access %x, offset %d, size %d, address %p",
rec->get_fd (), rec->get_handle (), rec->get_access (),
rec->get_offset (), rec->get_size (), rec->get_address ());
BOOL ret;
fhandler_disk_file fh_paging_file (NULL);
fhandler_base *fh;
if (rec->get_fd () == -1) /* MAP_ANONYMOUS */
fh = &fh_paging_file;
else
fh = fdtab[rec->get_fd ()];
ret = fh->fixup_mmap_after_fork (rec->get_handle (),
rec->get_access (),
rec->get_offset (),
rec->get_size (),
rec->get_address ());
if (!ret)
{
system_printf ("base address fails to match requested address %p",
rec->get_address ());
return -1;
}
rec->fixup_map ();
}
}
}
debug_printf ("succeeded");
return 0;
}
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