mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 13:00:06 +00:00
143 lines
4.0 KiB
C
143 lines
4.0 KiB
C
/* Copyright (C) 2000-2023 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
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <unistd.h>
|
|
#include <stdint.h>
|
|
#include <sys/fcntl.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/statfs.h>
|
|
|
|
/* Reserve storage for the data of the file associated with FD. This
|
|
emulation is far from perfect, but the kernel cannot do not much
|
|
better for network file systems, either. */
|
|
|
|
int
|
|
__posix_fallocate64_l64 (int fd, __off64_t offset, __off64_t len)
|
|
{
|
|
struct __stat64_t64 st;
|
|
|
|
if (offset < 0 || len < 0)
|
|
return EINVAL;
|
|
|
|
/* Perform overflow check. The outer cast relies on a GCC
|
|
extension. */
|
|
if ((__off64_t) ((uint64_t) offset + (uint64_t) len) < 0)
|
|
return EFBIG;
|
|
|
|
/* pwrite64 below will not do the right thing in O_APPEND mode. */
|
|
{
|
|
int flags = __fcntl (fd, F_GETFL, 0);
|
|
if (flags < 0 || (flags & O_APPEND) != 0)
|
|
return EBADF;
|
|
}
|
|
|
|
/* We have to make sure that this is really a regular file. */
|
|
if (__fstat64_time64 (fd, &st) != 0)
|
|
return EBADF;
|
|
if (S_ISFIFO (st.st_mode))
|
|
return ESPIPE;
|
|
if (! S_ISREG (st.st_mode))
|
|
return ENODEV;
|
|
|
|
if (len == 0)
|
|
{
|
|
/* This is racy, but there is no good way to satisfy a
|
|
zero-length allocation request. */
|
|
if (st.st_size < offset)
|
|
{
|
|
int ret = __ftruncate64 (fd, offset);
|
|
|
|
if (ret != 0)
|
|
ret = errno;
|
|
return ret;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Minimize data transfer for network file systems, by issuing
|
|
single-byte write requests spaced by the file system block size.
|
|
(Most local file systems have fallocate support, so this fallback
|
|
code is not used there.) */
|
|
|
|
unsigned increment;
|
|
{
|
|
struct statfs64 f;
|
|
|
|
if (__fstatfs64 (fd, &f) != 0)
|
|
return errno;
|
|
if (f.f_bsize == 0)
|
|
increment = 512;
|
|
else if (f.f_bsize < 4096)
|
|
increment = f.f_bsize;
|
|
else
|
|
/* NFS clients do not propagate the block size of the underlying
|
|
storage and may report a much larger value which would still
|
|
leave holes after the loop below, so we cap the increment at
|
|
4096. */
|
|
increment = 4096;
|
|
}
|
|
|
|
/* Write a null byte to every block. This is racy; we currently
|
|
lack a better option. Compare-and-swap against a file mapping
|
|
might address local races, but requires interposition of a signal
|
|
handler to catch SIGBUS. */
|
|
for (offset += (len - 1) % increment; len > 0; offset += increment)
|
|
{
|
|
len -= increment;
|
|
|
|
if (offset < st.st_size)
|
|
{
|
|
unsigned char c;
|
|
ssize_t rsize = __libc_pread64 (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 (__libc_pwrite64 (fd, "", 1, offset) != 1)
|
|
return errno;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#undef __posix_fallocate64_l64
|
|
#include <shlib-compat.h>
|
|
#include <bits/wordsize.h>
|
|
|
|
#if __WORDSIZE == 32 && SHLIB_COMPAT(libc, GLIBC_2_2, GLIBC_2_3_3)
|
|
|
|
int
|
|
attribute_compat_text_section
|
|
__posix_fallocate64_l32 (int fd, off64_t offset, size_t len)
|
|
{
|
|
return __posix_fallocate64_l64 (fd, offset, len);
|
|
}
|
|
|
|
versioned_symbol (libc, __posix_fallocate64_l64, posix_fallocate64,
|
|
GLIBC_2_3_3);
|
|
compat_symbol (libc, __posix_fallocate64_l32, posix_fallocate64, GLIBC_2_2);
|
|
#else
|
|
strong_alias (__posix_fallocate64_l64, posix_fallocate64);
|
|
#endif
|