/* 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 #include #include #include #include #include "fhandler.h" #include "dtable.h" #include "cygerrno.h" #include "cygheap.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_; int devtype_; 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), devtype_ (0), access_mode_ (ac), offset_ (o), size_to_map_ (s), base_address_ (b), map_map_ (NULL) { if (fd >= 0 && !cygheap->fdtab.not_open (fd)) devtype_ = cygheap->fdtab[fd]->get_device (); } /* Default Copy constructor/operator=/destructor are ok */ /* Simple accessors */ int get_fd () const { return fdesc_; } HANDLE get_handle () const { return mapping_handle_; } DWORD get_device () const { return devtype_; } 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); fhandler_base *alloc_fh (); void free_fh (fhandler_base *fh); }; 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); } static fhandler_disk_file fh_paging_file (NULL); fhandler_base * mmap_record::alloc_fh () { if (get_fd () == -1) { fh_paging_file.set_io_handle (INVALID_HANDLE_VALUE); return &fh_paging_file; } /* The file descriptor could have been closed or, even worse, could have been reused for another file before the call to fork(). This requires creating a fhandler of the correct type to be sure to call the method of the correct class. */ return cygheap->fdtab.build_fhandler (-1, get_device (), "", 0); } void mmap_record::free_fh (fhandler_base *fh) { if (get_fd () != -1) cfree (fh); } 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; ifd == 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) || (fd != -1 && lists[i]->hash == cygheap->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 = cygheap->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; /* copy-on-write doesn't work correctly on 9x. To have at least read access we use *READ mapping on 9x when appropriate. It will still fail when needing write access, though. */ if ((flags & MAP_PRIVATE) && (os_being_run == winNT || (prot & ~PROT_READ))) 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_base *fh = NULL; caddr_t base = addr; HANDLE h; if (fd != -1) { /* Ensure that fd is open */ if (cygheap->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 = cygheap->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_ANON in a special case of MAP_PRIVATE. */ if (l && 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) { off_t li = -1; if ((li = l->match(addr, len, li)) >= 0) { mmap_record *rec = l->recs + li; if (rec->unmap_map (addr, len)) { fhandler_base *fh = rec->alloc_fh (); fh->munmap (rec->get_handle (), addr, len); rec->free_fh (fh); /* 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) { for (int li = 0; li < l->nrecs; ++li) { mmap_record *rec = l->recs + li; if (rec->get_address () == addr) { fhandler_base *fh = rec->alloc_fh (); int ret = fh->msync (rec->get_handle (), addr, len, flags); rec->free_fh (fh); 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 ()); fhandler_base *fh = rec->alloc_fh (); BOOL ret = fh->fixup_mmap_after_fork (rec->get_handle (), rec->get_access (), rec->get_offset (), rec->get_size (), rec->get_address ()); rec->free_fh (fh); 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; }