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tmpfs: fix tmpfs_read overwrite after seek over tfo_size

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reproduce:
fs = open("tmpfs", xx);
lseek(fd, 256, SEEK_END);  // filep->f_pos = size + 256
read(fd, buf, len);        // overwrite

resolve:
directly return 0 when seek over tfo_size

Signed-off-by: ligd <liguiding1@xiaomi.com>
This commit is contained in:
ligd 2023-07-11 21:42:41 +08:00 committed by Xiang Xiao
parent d5a8746be8
commit ea03d06ab3
1 changed files with 7 additions and 16 deletions
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23
fs/tmpfs/fs_tmpfs.c
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@ -1467,6 +1467,13 @@ static ssize_t tmpfs_read(FAR struct file *filep, FAR char *buffer,
tfo = filep->f_priv;
/* Directly return when the f_pos bigger then tfo_size */
if (filep->f_pos > tfo->tfo_size)
{
return 0;
}
/* Get exclusive access to the file */
ret = tmpfs_lock_file(tfo);
@ -1611,22 +1618,6 @@ static off_t tmpfs_seek(FAR struct file *filep, off_t offset, int whence)
return -EINVAL;
}
/* Attempts to set the position beyond the end of file will
* work if the file is open for write access.
*
* REVISIT: This simple implementation has no per-open storage that
* would be needed to retain the open flags.
*/
#if 0
if (position > tfo->tfo_size && (tfo->tfo_oflags & O_WROK) == 0)
{
/* Otherwise, the position is limited to the file size */
position = tfo->tfo_size;
}
#endif
/* Save the new file position */
filep->f_pos = position;