diff options
author | Kevin Kirspel <kevin-kirspel@idexx.com> | 2017-06-29 10:36:43 -0400 |
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committer | Gedare Bloom <gedare@rtems.org> | 2017-07-14 16:04:05 -0400 |
commit | c6bb1c33bcf70d1398073c96a4fac4f9b031b9ab (patch) | |
tree | ce904d8bfaded9060edf71bac28c517c3e75a4c8 /cpukit/posix/src | |
parent | bsps: Include missing header file (diff) | |
download | rtems-c6bb1c33bcf70d1398073c96a4fac4f9b031b9ab.tar.bz2 |
posix/mmap: Add support for file handler and MAP_ANON
Added a mmap file handler to struct _rtems_filesystem_file_handlers_r.
Updated each file handler object to support the default mmap handler.
Updated mmap() to call the mmap handler for MAP_SHARED.
Added a mmap file handler for shm
Added support for MAP_ANON in mmap().
Updates #2859
Diffstat (limited to 'cpukit/posix/src')
-rw-r--r-- | cpukit/posix/src/mmap.c | 257 | ||||
-rw-r--r-- | cpukit/posix/src/munmap.c | 14 | ||||
-rw-r--r-- | cpukit/posix/src/shmopen.c | 30 |
3 files changed, 188 insertions, 113 deletions
diff --git a/cpukit/posix/src/mmap.c b/cpukit/posix/src/mmap.c index 5b6ac2e209..d9b663dd1e 100644 --- a/cpukit/posix/src/mmap.c +++ b/cpukit/posix/src/mmap.c @@ -5,6 +5,7 @@ /* * Copyright (c) 2012 Chris Johns (chrisj@rtems.org) * Copyright (c) 2017 Gedare Bloom (gedare@rtems.org) + * Copyright (c) 2017 Kevin kirspel (kirspkt@gmail.com) * * The license and distribution terms for this file may be * found in the file LICENSE in this distribution or at @@ -107,30 +108,6 @@ bool mmap_mappings_lock_release( return true; } -/* Helper function only gets called for mmap mappings of shared memory objects - * with the MAP_SHARED flag. - */ -static void *shm_mmap( rtems_libio_t *iop, size_t len, int prot, off_t off) -{ - POSIX_Shm_Control *shm = iop_to_shm( iop ); - void *m; - - _Objects_Allocator_lock(); - - m = (*shm->shm_object.ops->object_mmap)( &shm->shm_object, len, prot, off); - if ( m != NULL ) { - /* Keep a reference in the shared memory to prevent its removal. */ - ++shm->reference_count; - - /* Update atime */ - _POSIX_Shm_Update_atime(shm); - } - - _Objects_Allocator_unlock(); - - return m; -} - void *mmap( void *addr, size_t len, int prot, int flags, int fildes, off_t off ) @@ -140,37 +117,25 @@ void *mmap( ssize_t r; rtems_libio_t *iop; bool map_fixed; + bool map_anonymous; + bool map_shared; + bool map_private; + int err; map_fixed = (flags & MAP_FIXED) == MAP_FIXED; + map_anonymous = (flags & MAP_ANON) == MAP_ANON; + map_shared = (flags & MAP_SHARED) == MAP_SHARED; + map_private = (flags & MAP_PRIVATE) == MAP_PRIVATE; /* Clear errno. */ errno = 0; - - /* - * Get a stat of the file to get the dev + inode number and to make sure the - * fd is ok. The normal libio calls cannot be used because we need to return - * MAP_FAILED on error and they return -1 directly without coming back to - * here. - */ - if ( fstat( fildes, &sb ) < 0 ) { - errno = EBADF; - return MAP_FAILED; - } - - /* fstat ensures we have a good file descriptor. Hold on to iop. */ - iop = rtems_libio_iop( fildes ); + iop = NULL; if ( len == 0 ) { errno = EINVAL; return MAP_FAILED; } - /* Check the type of file we have and make sure it is supported. */ - if ( S_ISDIR( sb.st_mode ) || S_ISLNK( sb.st_mode )) { - errno = ENODEV; - return MAP_FAILED; - } - /* * We can provide read, write and execute because the memory in RTEMS does * not normally have protections but we cannot hide access to memory. @@ -180,17 +145,6 @@ void *mmap( return MAP_FAILED; } - /* Either MAP_SHARED or MAP_PRIVATE must be defined, but not both */ - if ( (flags & MAP_SHARED) == MAP_SHARED ) { - if ( (flags & MAP_PRIVATE) == MAP_PRIVATE ) { - errno = EINVAL; - return MAP_FAILED; - } - } else if ( (flags & MAP_PRIVATE) != MAP_PRIVATE ) { - errno = EINVAL; - return MAP_FAILED; - } - /* * We can not normally provide restriction of write access. Reject any * attempt to map without write permission, since we are not able to @@ -201,27 +155,104 @@ void *mmap( return MAP_FAILED; } - /* Check to see if the mapping is valid for a regular file. */ - if ( S_ISREG( sb.st_mode ) - /* FIXME: Should this be using strict inequality (>) comparisons? It would - * be valid to map a region exactly equal to the st_size, e.g. see below. */ - && (( off >= sb.st_size ) || (( off + len ) >= sb.st_size ))) { - errno = EOVERFLOW; + /* + * Anonymous mappings must have file descriptor set to -1 and the offset + * set to 0. Shared mappings are not supported with Anonymous mappings at + * this time + */ + if ( map_anonymous && (fildes != -1 || off != 0 || map_shared) ) { + errno = EINVAL; return MAP_FAILED; } /* - * Check to see if the mapping is valid for other file/object types. - * Does this satisfy for devices? + * If MAP_ANON is declared without MAP_PRIVATE or MAP_SHARED, + * force MAP_PRIVATE */ - if ( sb.st_size < off + len ) { - errno = ENXIO; + if ( map_anonymous && !map_private && !map_shared ) { + flags |= MAP_PRIVATE; + map_private = true; + } + + /* Check for supported flags */ + if ((flags & ~(MAP_SHARED | MAP_PRIVATE | MAP_FIXED | MAP_ANON)) != 0) { + errno = EINVAL; return MAP_FAILED; } - /* Do not seek on character devices, pipes, sockets, or memory objects. */ - if ( S_ISREG( sb.st_mode ) || S_ISBLK( sb.st_mode ) ) { - if ( lseek( fildes, off, SEEK_SET ) < 0 ) { + /* Either MAP_SHARED or MAP_PRIVATE must be defined, but not both */ + if ( map_shared ) { + if ( map_private ) { + errno = EINVAL; + return MAP_FAILED; + } + } else if ( !map_private ) { + errno = EINVAL; + return MAP_FAILED; + } + + /* Check for illegal addresses. Watch out for address wrap. */ + if ( map_fixed ) { + if ((uintptr_t)addr & PAGE_MASK) { + errno = EINVAL; + return MAP_FAILED; + } + if ( addr == NULL ) { + errno = EINVAL; + return MAP_FAILED; + } + if (addr + len < addr) { + errno = EINVAL; + return MAP_FAILED; + } + } + + if ( !map_anonymous ) { + /* + * Get a stat of the file to get the dev + inode number and to make sure the + * fd is ok. The normal libio calls cannot be used because we need to return + * MAP_FAILED on error and they return -1 directly without coming back to + * here. + */ + if ( fstat( fildes, &sb ) < 0 ) { + errno = EBADF; + return MAP_FAILED; + } + + /* fstat ensures we have a good file descriptor. Hold on to iop. */ + iop = rtems_libio_iop( fildes ); + + /* Check the type of file we have and make sure it is supported. */ + if ( S_ISDIR( sb.st_mode ) || S_ISLNK( sb.st_mode )) { + errno = ENODEV; + return MAP_FAILED; + } + + /* Check to see if the mapping is valid for a regular file. */ + if ( S_ISREG( sb.st_mode ) + /* FIXME: Should this be using strict inequality (>) comparisons? It would + * be valid to map a region exactly equal to the st_size, e.g. see below. */ + && (( off >= sb.st_size ) || (( off + len ) >= sb.st_size ))) { + errno = EOVERFLOW; + return MAP_FAILED; + } + + /* Check to see if the mapping is valid for other file/object types. */ + if ( !S_ISCHR( sb.st_mode ) && sb.st_size < off + len ) { + errno = ENXIO; + return MAP_FAILED; + } + + /* Do not seek on character devices, pipes, sockets, or memory objects. */ + if ( S_ISREG( sb.st_mode ) || S_ISBLK( sb.st_mode ) ) { + if ( lseek( fildes, off, SEEK_SET ) < 0 ) { + return MAP_FAILED; + } + } + + /* cdevs do not provide private mappings of any kind. */ + if ( S_ISCHR( sb.st_mode ) && map_private ) { + errno = EINVAL; return MAP_FAILED; } } @@ -230,42 +261,37 @@ void *mmap( mapping = malloc( sizeof( mmap_mapping )); if ( !mapping ) { errno = ENOMEM; - return NULL; + return MAP_FAILED; } memset( mapping, 0, sizeof( mmap_mapping )); mapping->len = len; mapping->flags = flags; mapping->iop = iop; - /* - * HACK: We should have a better generic way to distinguish between - * shm objects and other mmap'd files. We need to know at munmap time - * if the mapping is to a shared memory object in order to refcnt shms. - * We could do this by providing mmap in the file operations if needed. - */ - if ( S_ISREG( sb.st_mode ) || S_ISBLK( sb.st_mode ) || - S_ISCHR( sb.st_mode ) || S_ISFIFO( sb.st_mode ) || - S_ISSOCK( sb.st_mode ) ) { - mapping->is_shared_shm = false; + if ( !map_anonymous ) { + /* + * HACK: We should have a better generic way to distinguish between + * shm objects and other mmap'd files. We need to know at munmap time + * if the mapping is to a shared memory object in order to refcnt shms. + * We could do this by providing mmap in the file operations if needed. + */ + if ( S_ISREG( sb.st_mode ) || S_ISBLK( sb.st_mode ) || + S_ISCHR( sb.st_mode ) || S_ISFIFO( sb.st_mode ) || + S_ISSOCK( sb.st_mode ) ) { + mapping->is_shared_shm = false; + } else { + mapping->is_shared_shm = true; + } } else { - mapping->is_shared_shm = true; - } - - /* - * MAP_SHARED currently is only supported for shared memory objects. - */ - if ( (MAP_SHARED == (flags & MAP_SHARED)) && (mapping->is_shared_shm == false) ) { - free( mapping ); - errno = ENOTSUP; - return MAP_FAILED; + mapping->is_shared_shm = false; } if ( map_fixed ) { mapping->addr = addr; - } else if ( MAP_PRIVATE == (flags & MAP_PRIVATE) ) { + } else if ( map_private ) { /* private mappings of shared memory do not need special treatment. */ mapping->is_shared_shm = false; - mapping->addr = malloc( len ); + posix_memalign( &mapping->addr, PAGE_SIZE, len ); if ( !mapping->addr ) { free( mapping ); errno = ENOMEM; @@ -306,32 +332,43 @@ void *mmap( } /* Populate the data */ - if ( MAP_PRIVATE == (flags & MAP_PRIVATE) ) { - /* - * Use read() for private mappings. This updates atime as needed. - * Changes to the underlying object will NOT be reflected in the mapping. - * The underlying object can be removed while the mapping exists. - */ - r = read( fildes, mapping->addr, len ); + if ( map_private ) { + if ( !map_anonymous ) { + /* + * Use read() for private mappings. This updates atime as needed. + * Changes to the underlying object will NOT be reflected in the mapping. + * The underlying object can be removed while the mapping exists. + */ + r = read( fildes, mapping->addr, len ); - if ( r != len ) { - mmap_mappings_lock_release( ); - if ( !map_fixed ) { - free( mapping->addr ); + if ( r != len ) { + mmap_mappings_lock_release( ); + if ( !map_fixed ) { + free( mapping->addr ); + } + free( mapping ); + errno = ENXIO; + return MAP_FAILED; } + } else if ( !map_fixed ) { + memset( mapping->addr, 0, len ); + } + } else if ( map_shared ) { + err = (*iop->pathinfo.handlers->mmap_h)( + iop, &mapping->addr, len, prot, off ); + if ( err != 0 ) { + mmap_mappings_lock_release( ); free( mapping ); - errno = ENXIO; return MAP_FAILED; } - } else if ( MAP_SHARED == (flags & MAP_SHARED) ) { - /* Currently only shm objects can be MAP_SHARED. */ - mapping->addr = shm_mmap(iop, len, prot, off); } - /* add an extra reference to the file associated with fildes that - * is not removed by a subsequent close(). This reference shall be removed - * when there are no more mappings to the file. */ - rtems_libio_increment_mapping_refcnt(iop); + if ( iop != NULL ) { + /* add an extra reference to the file associated with fildes that + * is not removed by a subsequent close(). This reference shall be removed + * when there are no more mappings to the file. */ + rtems_libio_increment_mapping_refcnt(iop); + } rtems_chain_append( &mmap_mappings, &mapping->node ); diff --git a/cpukit/posix/src/munmap.c b/cpukit/posix/src/munmap.c index 323a24e6f4..2d812ae041 100644 --- a/cpukit/posix/src/munmap.c +++ b/cpukit/posix/src/munmap.c @@ -46,6 +46,12 @@ int munmap(void *addr, size_t len) return -1; } + /* Check for illegal addresses. Watch out for address wrap. */ + if (addr + len < addr) { + errno = EINVAL; + return -1; + } + /* * Obtain the mmap lock. Sets errno on failure. */ @@ -63,9 +69,11 @@ int munmap(void *addr, size_t len) if ( mapping->is_shared_shm == true ) { shm_munmap(mapping->iop); } - refcnt = rtems_libio_decrement_mapping_refcnt(mapping->iop); - if ( refcnt == 0 ) { - rtems_libio_check_deferred_free(mapping->iop); + if ( mapping->iop != NULL ) { + refcnt = rtems_libio_decrement_mapping_refcnt(mapping->iop); + if ( refcnt == 0 ) { + rtems_libio_check_deferred_free(mapping->iop); + } } /* only free the mapping address for non-fixed mapping */ if (( mapping->flags & MAP_FIXED ) != MAP_FIXED ) { diff --git a/cpukit/posix/src/shmopen.c b/cpukit/posix/src/shmopen.c index fa1027e30c..e729f9bd4e 100644 --- a/cpukit/posix/src/shmopen.c +++ b/cpukit/posix/src/shmopen.c @@ -106,6 +106,35 @@ static int shm_close( rtems_libio_t *iop ) return 0; } +static int shm_mmap( + rtems_libio_t *iop, + void** addr, + size_t len, + int prot, + off_t off +) +{ + POSIX_Shm_Control *shm = iop_to_shm( iop ); + + _Objects_Allocator_lock(); + + *addr = (*shm->shm_object.ops->object_mmap)( &shm->shm_object, len, prot, off); + if ( *addr != NULL ) { + /* Keep a reference in the shared memory to prevent its removal. */ + ++shm->reference_count; + + /* Update atime */ + _POSIX_Shm_Update_atime(shm); + } else { + _Objects_Allocator_unlock(); + rtems_set_errno_and_return_minus_one( ENOMEM ); + } + + _Objects_Allocator_unlock(); + + return 0; +} + static inline POSIX_Shm_Control *shm_allocate( const char *name_arg, size_t name_len, @@ -275,6 +304,7 @@ static const rtems_filesystem_file_handlers_r shm_handlers = { .fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync, .fcntl_h = rtems_filesystem_default_fcntl, .kqfilter_h = rtems_filesystem_default_kqfilter, + .mmap_h = shm_mmap, .poll_h = rtems_filesystem_default_poll, .readv_h = rtems_filesystem_default_readv, .writev_h = rtems_filesystem_default_writev |