diff options
Diffstat (limited to 'cpukit/libfs/src/defaults/default_lseek_file.c')
-rw-r--r-- | cpukit/libfs/src/defaults/default_lseek_file.c | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/cpukit/libfs/src/defaults/default_lseek_file.c b/cpukit/libfs/src/defaults/default_lseek_file.c new file mode 100644 index 0000000000..9d80b2a176 --- /dev/null +++ b/cpukit/libfs/src/defaults/default_lseek_file.c @@ -0,0 +1,70 @@ +/* + * Copyright (c) 2012 embedded brains GmbH. All rights reserved. + * + * embedded brains GmbH + * Obere Lagerstr. 30 + * 82178 Puchheim + * Germany + * <rtems@embedded-brains.de> + * + * The license and distribution terms for this file may be + * found in the file LICENSE in this distribution or at + * http://www.rtems.com/license/LICENSE. + */ + +#if HAVE_CONFIG_H + #include "config.h" +#endif + +#include <rtems/libio_.h> + +off_t rtems_filesystem_default_lseek_file( + rtems_libio_t *iop, + off_t offset, + int whence +) +{ + off_t rv = 0; + off_t reference_offset; + off_t new_offset; + struct stat st; + + switch ( whence ) { + case SEEK_SET: + reference_offset = 0; + break; + case SEEK_CUR: + reference_offset = iop->offset; + break; + case SEEK_END: + st.st_size = 0; + rv = (*iop->pathinfo.handlers->fstat_h)( &iop->pathinfo, &st ); + reference_offset = st.st_size; + break; + default: + errno = EINVAL; + rv = -1; + break; + } + new_offset = reference_offset + offset; + + if ( rv == 0 ) { + if ( + (offset >= 0 && new_offset >= reference_offset) + || (offset < 0 && new_offset < reference_offset) + ) { + if ( new_offset >= 0 ) { + iop->offset = new_offset; + rv = new_offset; + } else { + errno = EINVAL; + rv = -1; + } + } else { + errno = EOVERFLOW; + rv = -1; + } + } + + return rv; +} |