mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-26 23:10:06 +00:00
94 lines
2.4 KiB
C
94 lines
2.4 KiB
C
/* Copyright (C) 2000-2014 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <unistd.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/statfs.h>
|
|
|
|
/* Reserve storage for the data of the file associated with FD. */
|
|
|
|
int
|
|
posix_fallocate (int fd, __off_t offset, __off_t len)
|
|
{
|
|
struct stat64 st;
|
|
struct statfs f;
|
|
|
|
/* `off_t' is a signed type. Therefore we can determine whether
|
|
OFFSET + LEN is too large if it is a negative value. */
|
|
if (offset < 0 || len < 0)
|
|
return EINVAL;
|
|
if (offset + len < 0)
|
|
return EFBIG;
|
|
|
|
/* First thing we have to make sure is that this is really a regular
|
|
file. */
|
|
if (__fxstat64 (_STAT_VER, fd, &st) != 0)
|
|
return EBADF;
|
|
if (S_ISFIFO (st.st_mode))
|
|
return ESPIPE;
|
|
if (! S_ISREG (st.st_mode))
|
|
return ENODEV;
|
|
|
|
if (len == 0)
|
|
{
|
|
if (st.st_size < offset)
|
|
{
|
|
int ret = __ftruncate (fd, offset);
|
|
|
|
if (ret != 0)
|
|
ret = errno;
|
|
return ret;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* We have to know the block size of the filesystem to get at least some
|
|
sort of performance. */
|
|
if (__fstatfs (fd, &f) != 0)
|
|
return errno;
|
|
|
|
/* Try to play safe. */
|
|
if (f.f_bsize == 0)
|
|
f.f_bsize = 512;
|
|
|
|
/* Write something to every block. */
|
|
for (offset += (len - 1) % f.f_bsize; len > 0; offset += f.f_bsize)
|
|
{
|
|
len -= f.f_bsize;
|
|
|
|
if (offset < st.st_size)
|
|
{
|
|
unsigned char c;
|
|
ssize_t rsize = __pread (fd, &c, 1, offset);
|
|
|
|
if (rsize < 0)
|
|
return errno;
|
|
/* If there is a non-zero byte, the block must have been
|
|
allocated already. */
|
|
else if (rsize == 1 && c != 0)
|
|
continue;
|
|
}
|
|
|
|
if (__pwrite (fd, "", 1, offset) != 1)
|
|
return errno;
|
|
}
|
|
|
|
return 0;
|
|
}
|