libcsupport: Add and use rtems_libio_iovec_eval()

3 files changed, 87 insertions, 155 deletions

diff --git a/cpukit/libcsupport/include/rtems/libio_.h b/cpukit/libcsupport/include/rtems/libio_.h
index bf01cd5659..995d621f79 100644
--- a/cpukit/libcsupport/include/rtems/libio_.h
+++ b/cpukit/libcsupport/include/rtems/libio_.h
@@ -21,7 +21,9 @@
 #ifndef _RTEMS_RTEMS_LIBIO__H
 #define _RTEMS_RTEMS_LIBIO__H
 
+#include <sys/uio.h>
 #include <errno.h>
+#include <limits.h>
 
 #include <rtems.h>
 #include <rtems/libio.h>
@@ -839,6 +841,60 @@ static inline bool rtems_filesystem_is_parent_directory(
   return tokenlen == 2 && token [0] == '.' && token [1] == '.';
 }
 
+static inline ssize_t rtems_libio_iovec_eval(
+  int fd,
+  const struct iovec *iov,
+  int iovcnt,
+  uint32_t flags,
+  rtems_libio_t **iopp
+)
+{
+  ssize_t        total;
+  int            v;
+  rtems_libio_t *iop;
+
+  rtems_libio_check_fd( fd );
+  iop = rtems_libio_iop( fd );
+  rtems_libio_check_is_open( iop );
+  rtems_libio_check_permissions_with_error( iop, flags, EBADF );
+
+  *iopp = iop;
+
+  /*
+   *  Argument validation on IO vector
+   */
+  if ( iov == NULL )
+    rtems_set_errno_and_return_minus_one( EINVAL );
+
+  if ( iovcnt <= 0 )
+    rtems_set_errno_and_return_minus_one( EINVAL );
+
+  if ( iovcnt > IOV_MAX )
+    rtems_set_errno_and_return_minus_one( EINVAL );
+
+  /*
+   *  OpenGroup says that you are supposed to return EINVAL if the
+   *  sum of the iov_len values in the iov array would overflow a
+   *  ssize_t.
+   */
+  total = 0;
+  for ( v = 0 ; v < iovcnt ; ++v ) {
+    size_t len = iov[ v ].iov_len;
+
+    if ( len > ( size_t ) ( SSIZE_MAX - total ) ) {
+      rtems_set_errno_and_return_minus_one( EINVAL );
+    }
+
+    total += ( ssize_t ) len;
+
+    if ( iov[ v ].iov_base == NULL ) {
+      rtems_set_errno_and_return_minus_one( EINVAL );
+    }
+  }
+
+  return total;
+}
+
 /** @} */
 
 #ifdef __cplusplus
diff --git a/cpukit/libcsupport/src/readv.c b/cpukit/libcsupport/src/readv.c
index 2ff7f63767..e47f22850a 100644
--- a/cpukit/libcsupport/src/readv.c
+++ b/cpukit/libcsupport/src/readv.c
@@ -18,11 +18,9 @@
 #include "config.h"
 #endif
 
-#include <sys/types.h>
 #include <sys/uio.h>
 
 #include <rtems/libio_.h>
-#include <rtems/seterr.h>
 
 /**
  *  readv() - POSIX 1003.1 - Read a Vector
@@ -39,86 +37,30 @@ ssize_t readv(
 {
   ssize_t        total;
   int            v;
-  int            bytes;
   rtems_libio_t *iop;
-  bool           all_zeros;
 
-  rtems_libio_check_fd( fd );
-  iop = rtems_libio_iop( fd );
-  rtems_libio_check_is_open( iop );
-  rtems_libio_check_permissions_with_error( iop, LIBIO_FLAGS_READ, EBADF );
-
-  /*
-   *  Argument validation on IO vector
-   */
-  if ( !iov )
-    rtems_set_errno_and_return_minus_one( EINVAL );
-
-  if ( iovcnt <= 0 )
-    rtems_set_errno_and_return_minus_one( EINVAL );
-
-  if ( iovcnt > IOV_MAX )
-    rtems_set_errno_and_return_minus_one( EINVAL );
-
-  /*
-   *  OpenGroup says that you are supposed to return EINVAL if the
-   *  sum of the iov_len values in the iov array would overflow a
-   *  ssize_t.
-   *
-   *  Also we would like to ensure that no IO is performed if there
-   *  are obvious errors in the iovec.  So this extra loop ensures
-   *  that we do not do anything if there is an argument error.
-   */
-
-  all_zeros = true;
-  for ( total=0, v=0 ; v < iovcnt ; v++ ) {
-    ssize_t old;
+  total = rtems_libio_iovec_eval( fd, iov, iovcnt, LIBIO_FLAGS_READ, &iop );
 
+  if ( total > 0 ) {
     /*
-     *  iov[v].iov_len cannot be less than 0 because size_t is unsigned.
-     *  So we only check for zero.
+     *  Now process the readv().
      */
-    if ( iov[v].iov_base == 0 )
-      rtems_set_errno_and_return_minus_one( EINVAL );
+    total = 0;
+    for ( v = 0 ; v < iovcnt ; v++ ) {
+      ssize_t bytes = ( *iop->pathinfo.handlers->read_h )(
+        iop,
+        iov[ v ].iov_base,
+        iov[ v ].iov_len
+      );
 
-    /* check for wrap */
-    old    = total;
-    total += iov[v].iov_len;
-    if ( total < old )
-      rtems_set_errno_and_return_minus_one( EINVAL );
+      if ( bytes < 0 )
+        return -1;
 
-    if ( iov[v].iov_len )
-      all_zeros = false;
-  }
+      total += bytes;
 
-  /*
-   *  A readv with all zeros logically has no effect.  Even though
-   *  OpenGroup didn't address this case as they did with writev(),
-   *  we will handle it the same way for symmetry.
-   */
-  if ( all_zeros == true ) {
-    return 0;
-  }
-
-  /*
-   *  Now process the readv().
-   */
-  for ( total=0, v=0 ; v < iovcnt ; v++ ) {
-    bytes = (*iop->pathinfo.handlers->read_h)(
-      iop,
-      iov[v].iov_base,
-      iov[v].iov_len
-    );
-
-    if ( bytes < 0 )
-      return -1;
-
-    if ( bytes > 0 ) {
-      total       += bytes;
+      if ( bytes != iov[ v ].iov_len )
+        break;
     }
-
-    if (bytes != iov[ v ].iov_len)
-      break;
   }
 
   return total;
diff --git a/cpukit/libcsupport/src/writev.c b/cpukit/libcsupport/src/writev.c
index 47605a4cd9..4a8dc735b8 100644
--- a/cpukit/libcsupport/src/writev.c
+++ b/cpukit/libcsupport/src/writev.c
@@ -1,5 +1,5 @@
 /*
- *  writev() - POSIX 1003.1 - Read a Vector
+ *  writev() - POSIX 1003.1 - Write a Vector
  *
  *  OpenGroup URL:
  *
@@ -17,11 +17,9 @@
 #include "config.h"
 #endif
 
-#include <sys/types.h>
 #include <sys/uio.h>
 
 #include <rtems/libio_.h>
-#include <rtems/seterr.h>
 
 ssize_t writev(
   int                 fd,
@@ -31,95 +29,31 @@ ssize_t writev(
 {
   ssize_t        total;
   int            v;
-  int            bytes;
   rtems_libio_t *iop;
-  ssize_t        old;
-  bool           all_zeros;
 
-  rtems_libio_check_fd( fd );
-  iop = rtems_libio_iop( fd );
-  rtems_libio_check_is_open( iop );
-  rtems_libio_check_permissions_with_error( iop, LIBIO_FLAGS_WRITE, EBADF );
-
-  /*
-   *  Argument validation on IO vector
-   */
-  if ( !iov )
-    rtems_set_errno_and_return_minus_one( EINVAL );
-
-  if ( iovcnt <= 0 )
-    rtems_set_errno_and_return_minus_one( EINVAL );
-
-  if ( iovcnt > IOV_MAX )
-    rtems_set_errno_and_return_minus_one( EINVAL );
-
-  /*
-   *  OpenGroup says that you are supposed to return EINVAL if the
-   *  sum of the iov_len values in the iov array would overflow a
-   *  ssize_t.
-   *
-   *  Also we would like to ensure that no IO is performed if there
-   *  are obvious errors in the iovec.  So this extra loop ensures
-   *  that we do not do anything if there is an argument error.
-   *
-   *  In addition,the OpenGroup specification says that if all the
-   *  iov_len entries are zero, then the call has no effect.  So
-   *  this loop does that check as well and sets "all-zero" appropriately.
-   *  The variable "all_zero" is used as an early exit point before
-   *  entering the write loop.
-   */
-  all_zeros = true;
-  for ( old=0, total=0, v=0 ; v < iovcnt ; v++ ) {
+  total = rtems_libio_iovec_eval( fd, iov, iovcnt, LIBIO_FLAGS_WRITE, &iop );
 
+  if ( total > 0 ) {
     /*
-     *  iov[v].iov_len cannot be less than 0 because size_t is unsigned.
-     *  So we only check for zero.
+     *  Now process the writev().
      */
-    if ( iov[v].iov_base == 0 )
-      rtems_set_errno_and_return_minus_one( EINVAL );
-
-    if ( iov[v].iov_len )
-      all_zeros = false;
-
-    /* check for wrap */
-    old    = total;
-    total += iov[v].iov_len;
-    if ( total < old || total > SSIZE_MAX )
-      rtems_set_errno_and_return_minus_one( EINVAL );
-  }
-
-  /*
-   * A writev with all zeros is supposed to have no effect per OpenGroup.
-   */
-  if ( all_zeros == true ) {
-    return 0;
-  }
+    total = 0;
+    for ( v = 0 ; v < iovcnt ; v++ ) {
+      ssize_t bytes = ( *iop->pathinfo.handlers->write_h )(
+        iop,
+        iov[ v ].iov_base,
+        iov[ v ].iov_len
+      );
 
-  /*
-   *  Now process the writev().
-   */
-  for ( total=0, v=0 ; v < iovcnt ; v++ ) {
-    /* all zero lengths has no effect */
-    if ( iov[v].iov_len == 0 )
-      continue;
+      if ( bytes < 0 )
+        return -1;
 
-    bytes = (*iop->pathinfo.handlers->write_h)(
-      iop,
-      iov[v].iov_base,
-      iov[v].iov_len
-    );
+      total += bytes;
 
-    if ( bytes < 0 )
-      return -1;
-
-    if ( bytes > 0 ) {
-      total       += bytes;
+      if ( bytes != iov[ v ].iov_len )
+        break;
     }
-
-    if (bytes != iov[ v ].iov_len)
-      break;
   }
 
   return total;
 }
-