Update #2859.
---
cpukit/posix/include/rtems/posix/mmanimpl.h | 4 ++-
cpukit/posix/src/mmap.c | 43 +++++++++++++++++++++++++++--
2 files changed, 43 insertions(+), 4 deletions(-)
diff --git a/cpukit/posix/include/rtems/posix/mmanimpl.h
b/cpukit/posix/include/rtems/posix/mmanimpl.h
index 9743685..78bda53 100644
--- a/cpukit/posix/include/rtems/posix/mmanimpl.h
+++ b/cpukit/posix/include/rtems/posix/mmanimpl.h
@@ -16,12 +16,14 @@
#ifndef _RTEMS_POSIX_MMANIMPL_H
#define _RTEMS_POSIX_MMANIMPL_H
-#include <rtems/chain.h>
+#include <rtems/chain.h> /* FIXME: use score chains for proper layering? */
#ifdef __cplusplus
extern "C" {
#endif
+/* FIXME: add Doxygen */
+
/**
* Every mmap'ed region has a mapping.
*/
diff --git a/cpukit/posix/src/mmap.c b/cpukit/posix/src/mmap.c
index c05a65e..3c5f81e 100644
--- a/cpukit/posix/src/mmap.c
+++ b/cpukit/posix/src/mmap.c
@@ -1,5 +1,10 @@
+/**
+ * @file
+ */
+
/*
* Copyright (c) 2012 Chris Johns (chr...@rtems.org)
+ * Copyright (c) 2017 Gedare Bloom (ged...@rtems.org)
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
@@ -49,11 +54,14 @@ bool mmap_mappings_lock_create(
* the libio lock is locked and we then test the mapping lock again. If not
* present we create the mapping lock then release libio lock.
*/
+ /* FIXME: double-checked locking anti-pattern. */
if ( mmap_mappings_lock == 0 ) {
rtems_status_code sc = RTEMS_SUCCESSFUL;
rtems_chain_initialize_empty( &mmap_mappings );
rtems_semaphore_obtain( rtems_libio_semaphore,
RTEMS_WAIT, RTEMS_NO_TIMEOUT );
+ /* FIXME: account for semaphore in confdefs, or maybe just use the
+ * rtems_libio_semaphore? */
if ( mmap_mappings_lock == 0 )
sc = rtems_semaphore_create( rtems_build_name( 'M', 'M', 'A', 'P' ),
1,
@@ -140,20 +148,40 @@ void *mmap(
* not normally have protections but we cannot hide access to memory.
*/
if ( prot == PROT_NONE ) {
- errno = EINVAL;
+ errno = ENOTSUP;
return MAP_FAILED;
}
/*
- * Check to see if the mapping is valid for the file.
+ * We can not normally provide restriction of write access. Reject any
+ * attempt to map without write permission, since we are not able to
+ * prevent a write from succeeding.
+ */
+ if ( PROT_WRITE != (prot & PROT_WRITE) ) {
+ errno = ENOTSUP;
+ 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 ( sb.st_size < off + len ) {
+ errno = ENXIO;
+ return MAP_FAILED;
+ }
+
+ /*
* Obtain the mmap lock. Sets errno on failure.
*/
if ( !mmap_mappings_lock_obtain( ) )
@@ -200,7 +228,7 @@ void *mmap(
}
/*
- * Do not seek on character devices, pipes or sockets.
+ * 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 ) {
@@ -212,6 +240,7 @@ void *mmap(
}
}
+ /* read updates atime satisfying POSIX spec for mmap */
r = read( fildes, mapping->addr, len );
if ( r != len ) {
@@ -222,6 +251,14 @@ void *mmap(
return MAP_FAILED;
}
+ /* FIXME: for a mapping with MAP_SHARED and PROT_WRITE the mtime/ctime
+ * should be updated when there is a write reference to the mapped region.
+ * How do we make this happen? */
+
+ /* FIXME: 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_chain_append( &mmap_mappings, &mapping->node );
mmap_mappings_lock_release( );
--
2.7.4
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