4.115
Last change
on this file since 30d4124 was
30d4124,
checked in by Sebastian Huber <sebastian.huber@…>, on 05/07/12 at 14:30:37
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Filesystem: PR1398: Fix lseek() mechanic
According to POSIX the lseek() function shall not, by itself, extend the
size of a file.
Remove the size field of rtems_libio_t. A file has only one size but
may have multiple open file descriptors. Thus a file size field in the
file descriptor may lead to inconsistencies.
New default handlers rtems_filesystem_default_lseek_file() and
rtems_filesystem_default_lseek_directory().
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-
Property mode set to
100644
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File size:
1.4 KB
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Rev | Line | |
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[30d4124] | 1 | /* |
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| 2 | * Copyright (c) 2012 embedded brains GmbH. All rights reserved. |
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| 3 | * |
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| 4 | * embedded brains GmbH |
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| 5 | * Obere Lagerstr. 30 |
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| 6 | * 82178 Puchheim |
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| 7 | * Germany |
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| 8 | * <rtems@embedded-brains.de> |
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| 9 | * |
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| 10 | * The license and distribution terms for this file may be |
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| 11 | * found in the file LICENSE in this distribution or at |
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| 12 | * http://www.rtems.com/license/LICENSE. |
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| 13 | */ |
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| 14 | |
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| 15 | #if HAVE_CONFIG_H |
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| 16 | #include "config.h" |
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| 17 | #endif |
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| 18 | |
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| 19 | #include <rtems/libio_.h> |
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| 20 | |
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| 21 | off_t rtems_filesystem_default_lseek_file( |
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| 22 | rtems_libio_t *iop, |
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| 23 | off_t offset, |
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| 24 | int whence |
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| 25 | ) |
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| 26 | { |
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| 27 | off_t rv = 0; |
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| 28 | off_t reference_offset; |
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| 29 | off_t new_offset; |
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| 30 | struct stat st; |
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| 31 | |
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| 32 | switch ( whence ) { |
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| 33 | case SEEK_SET: |
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| 34 | reference_offset = 0; |
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| 35 | break; |
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| 36 | case SEEK_CUR: |
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| 37 | reference_offset = iop->offset; |
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| 38 | break; |
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| 39 | case SEEK_END: |
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| 40 | st.st_size = 0; |
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| 41 | rv = (*iop->pathinfo.handlers->fstat_h)( &iop->pathinfo, &st ); |
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| 42 | reference_offset = st.st_size; |
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| 43 | break; |
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| 44 | default: |
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| 45 | errno = EINVAL; |
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| 46 | rv = -1; |
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| 47 | break; |
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| 48 | } |
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| 49 | new_offset = reference_offset + offset; |
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| 50 | |
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| 51 | if ( rv == 0 ) { |
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| 52 | if ( |
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| 53 | (offset >= 0 && new_offset >= reference_offset) |
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| 54 | || (offset < 0 && new_offset < reference_offset) |
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| 55 | ) { |
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| 56 | if ( new_offset >= 0 ) { |
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| 57 | iop->offset = new_offset; |
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| 58 | rv = new_offset; |
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| 59 | } else { |
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| 60 | errno = EINVAL; |
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| 61 | rv = -1; |
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| 62 | } |
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| 63 | } else { |
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| 64 | errno = EOVERFLOW; |
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| 65 | rv = -1; |
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| 66 | } |
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| 67 | } |
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| 68 | |
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| 69 | return rv; |
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| 70 | } |
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