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io: Remove copy_file_range emulation [BZ #24744]

Browse Source 
The kernel is evolving this interface (e.g., removal of the
restriction on cross-device copies), and keeping up with that
is difficult.  Applications which need the function should
run kernels which support the system call instead of relying on
the imperfect glibc emulation.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit 5a659ccc0e)
This commit is contained in:
Florian Weimer 2019-06-28 09:39:21 +02:00
parent 91b02c5b4d
commit 5f7fa9ac30
12 changed files with 78 additions and 776 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
ChangeLog
View File

@ -1,3 +1,39 @@
2019-06-28 Florian Weimer <fweimer@redhat.com>
[BZ #24744]
io: Remove the copy_file_range emulation.
* sysdeps/unix/sysv/linux/copy_file_range.c (copy_file_range): Do
not define and call copy_file_range_compat.
* io/Makefile (tests-static, tests-internal): Do not add
tst-copy_file_range-compat.
* io/copy_file_range-compat.c: Remove file.
* io/copy_file_range.c (copy_file_range): Define as stub.
* io/tst-copy_file_range-compat.c: Remove file.
* io/tst-copy_file_range.c (xdevfile): Remove variable.
(typical_sizes): Update comment. Remove 16K sizes.
(maximum_offset, maximum_offset_errno, maximum_offset_hard_limit):
Remove variables.
(find_maximum_offset, pipe_as_source, pipe_as_destination)
(delayed_write_failure_beginning, delayed_write_failure_end)
(cross_device_failure, enospc_failure_1, enospc_failure)
(oappend_failure): Remove functions.
(tests): Adjust test case list.
(do_test): Remove file system search code. Check for ENOSYS from
copy_file_range. Do not free xdevfile.
* manual/llio.texi (Copying File Data): Document ENOSYS error from
copy_file_range. Do not document the EXDEV error, which future
kernels may not report. Update the wording to reflect that
further errors are possible.
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
[__LINUX_KERNEL_VERSION < 0x040D00] (__ASSUME_COPY_FILE_RANGE): Do
not undefine.
* sysdeps/unix/sysv/linux/kernel-features.h
[__LINUX_KERNEL_VERSION >= 0x040500] (__ASSUME_COPY_FILE_RANGE):
Remove definition.
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
[__LINUX_KERNEL_VERSION < 0x040A00] (__ASSUME_COPY_FILE_RANGE): Do
not undefine.
2019-06-20 Dmitry V. Levin <ldv@altlinux.org>
Florian Weimer <fweimer@redhat.com>

9
NEWS
View File

@ -22,6 +22,14 @@ Deprecated and removed features, and other changes affecting compatibility:
HTM state is saved and restore lazily (the state being saved even when the
process actually does not use HTM).
* The copy_file_range function fails with ENOSYS if the kernel does not
support the system call of the same name. Previously, user space
emulation was performed, but its behavior did not match the kernel
behavior, which was deemed too confusing. Applications which use the
copy_file_range function will have to be run on kernels which implement
the copy_file_range system call. Support for most architectures was added
in version 4.5 of the mainline Linux kernel.
The following bugs are resolved with this release:
[18035] Fix pldd hang
@ -60,6 +68,7 @@ The following bugs are resolved with this release:
[24161] __run_fork_handlers self-deadlocks in malloc/tst-mallocfork2
[24228] old x86 applications that use legacy libio crash on exit
[24476] dlfcn: Guard __dlerror_main_freeres with __libc_once_get (once)
[24744] io: Remove the copy_file_range emulation.
Security related changes:

5
io/Makefile
View File

@ -73,11 +73,6 @@ tests := test-utime test-stat test-stat2 test-lfs tst-getcwd \
tst-fts tst-fts-lfs tst-open-tmpfile \
tst-copy_file_range tst-getcwd-abspath \
# This test includes the compat implementation of copy_file_range,
# which uses internal, unexported libc functions.
tests-static += tst-copy_file_range-compat
tests-internal += tst-copy_file_range-compat
# Likewise for statx, but we do not need static linking here.
tests-internal += tst-statx

160
io/copy_file_range-compat.c
View File

@ -1,160 +0,0 @@
/* Emulation of copy_file_range.
Copyright (C) 2017-2018 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/>. */
/* The following macros should be defined before including this
file:
COPY_FILE_RANGE_DECL Declaration specifiers for the function below.
COPY_FILE_RANGE Name of the function to define. */
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
COPY_FILE_RANGE_DECL
ssize_t
COPY_FILE_RANGE (int infd, __off64_t *pinoff,
int outfd, __off64_t *poutoff,
size_t length, unsigned int flags)
{
if (flags != 0)
{
__set_errno (EINVAL);
return -1;
}
{
struct stat64 instat;
struct stat64 outstat;
if (fstat64 (infd, &instat) != 0 || fstat64 (outfd, &outstat) != 0)
return -1;
if (S_ISDIR (instat.st_mode) || S_ISDIR (outstat.st_mode))
{
__set_errno (EISDIR);
return -1;
}
if (!S_ISREG (instat.st_mode) || !S_ISREG (outstat.st_mode))
{
/* We need a regular input file so that the we can seek
backwards in case of a write failure. */
__set_errno (EINVAL);
return -1;
}
if (instat.st_dev != outstat.st_dev)
{
/* Cross-device copies are not supported. */
__set_errno (EXDEV);
return -1;
}
}
/* The output descriptor must not have O_APPEND set. */
{
int flags = __fcntl (outfd, F_GETFL);
if (flags & O_APPEND)
{
__set_errno (EBADF);
return -1;
}
}
/* Avoid an overflow in the result. */
if (length > SSIZE_MAX)
length = SSIZE_MAX;
/* Main copying loop. The buffer size is arbitrary and is a
trade-off between stack size consumption, cache usage, and
amortization of system call overhead. */
size_t copied = 0;
char buf[8192];
while (length > 0)
{
size_t to_read = length;
if (to_read > sizeof (buf))
to_read = sizeof (buf);
/* Fill the buffer. */
ssize_t read_count;
if (pinoff == NULL)
read_count = read (infd, buf, to_read);
else
read_count = __libc_pread64 (infd, buf, to_read, *pinoff);
if (read_count == 0)
/* End of file reached prematurely. */
return copied;
if (read_count < 0)
{
if (copied > 0)
/* Report the number of bytes copied so far. */
return copied;
return -1;
}
if (pinoff != NULL)
*pinoff += read_count;
/* Write the buffer part which was read to the destination. */
char *end = buf + read_count;
for (char *p = buf; p < end; )
{
ssize_t write_count;
if (poutoff == NULL)
write_count = write (outfd, p, end - p);
else
write_count = __libc_pwrite64 (outfd, p, end - p, *poutoff);
if (write_count < 0)
{
/* Adjust the input read position to match what we have
written, so that the caller can pick up after the
error. */
size_t written = p - buf;
/* NB: This needs to be signed so that we can form the
negative value below. */
ssize_t overread = read_count - written;
if (pinoff == NULL)
{
if (overread > 0)
{
/* We are on an error recovery path, so we
cannot deal with failure here. */
int save_errno = errno;
(void) __libc_lseek64 (infd, -overread, SEEK_CUR);
__set_errno (save_errno);
}
}
else /* pinoff != NULL */
*pinoff -= overread;
if (copied + written > 0)
/* Report the number of bytes copied so far. */
return copied + written;
return -1;
}
p += write_count;
if (poutoff != NULL)
*poutoff += write_count;
} /* Write loop. */
copied += read_count;
length -= read_count;
}
return copied;
}

18
io/copy_file_range.c
View File

@ -1,5 +1,5 @@
/* Generic implementation of copy_file_range.
Copyright (C) 2017-2018 Free Software Foundation, Inc.
/* Stub implementation of copy_file_range.
Copyright (C) 2017-2019 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
@ -16,7 +16,15 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#define COPY_FILE_RANGE_DECL
#define COPY_FILE_RANGE copy_file_range
#include <errno.h>
#include <unistd.h>
#include <io/copy_file_range-compat.c>
ssize_t
copy_file_range (int infd, __off64_t *pinoff,
int outfd, __off64_t *poutoff,
size_t length, unsigned int flags)
{
__set_errno (ENOSYS);
return -1;
}
stub_warning (copy_file_range)

30
io/tst-copy_file_range-compat.c
View File

@ -1,30 +0,0 @@
/* Test the fallback implementation of copy_file_range.
Copyright (C) 2017-2018 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/>. */
/* Get the declaration of the official copy_of_range function. */
#include <unistd.h>
/* Compile a local version of copy_file_range. */
#define COPY_FILE_RANGE_DECL static
#define COPY_FILE_RANGE copy_file_range_compat
#include <io/copy_file_range-compat.c>
/* Re-use the test, but run it against copy_file_range_compat defined
above. */
#define copy_file_range copy_file_range_compat
#include "tst-copy_file_range.c"

557
io/tst-copy_file_range.c
View File

@ -1,5 +1,5 @@
/* Tests for copy_file_range.
Copyright (C) 2017-2018 Free Software Foundation, Inc.
Copyright (C) 2017-2019 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
@ -20,22 +20,15 @@
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libgen.h>
#include <poll.h>
#include <sched.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <support/check.h>
#include <support/namespace.h>
#include <support/support.h>
#include <support/temp_file.h>
#include <support/test-driver.h>
#include <support/xunistd.h>
#ifdef CLONE_NEWNS
# include <sys/mount.h>
#endif
/* Boolean flags which indicate whether to use pointers with explicit
output flags. */
@ -49,10 +42,6 @@ static int infd;
static char *outfile;
static int outfd;
/* Like the above, but on a different file system. xdevfile can be
NULL if no suitable file system has been found. */
static char *xdevfile;
/* Input and output offsets. Set according to do_inoff and do_outoff
before the test. The offsets themselves are always set to
zero. */
@ -61,13 +50,10 @@ static off64_t *pinoff;
static off64_t outoff;
static off64_t *poutoff;
/* These are a collection of copy sizes used in tests. The selection
takes into account that the fallback implementation uses an
internal buffer of 8192 bytes. */
/* These are a collection of copy sizes used in tests. */
enum { maximum_size = 99999 };
static const int typical_sizes[] =
{ 0, 1, 2, 3, 1024, 2048, 4096, 8191, 8192, 8193, 16383, 16384, 16385,
maximum_size };
{ 0, 1, 2, 3, 1024, 2048, 4096, 8191, 8192, 8193, maximum_size };
/* The random contents of this array can be used as a pattern to check
for correct write operations. */
@ -76,101 +62,6 @@ static unsigned char random_data[maximum_size];
/* The size chosen by the test harness. */
static int current_size;
/* Maximum writable file offset. Updated by find_maximum_offset
below. */
static off64_t maximum_offset;
/* Error code when crossing the offset. */
static int maximum_offset_errno;
/* If true: Writes which cross the limit will fail. If false: Writes
which cross the limit will result in a partial write. */
static bool maximum_offset_hard_limit;
/* Fills maximum_offset etc. above. Truncates outfd as a side
effect. */
static void
find_maximum_offset (void)
{
xftruncate (outfd, 0);
if (maximum_offset != 0)
return;
uint64_t upper = -1;
upper >>= 1; /* Maximum of off64_t. */
TEST_VERIFY ((off64_t) upper > 0);
TEST_VERIFY ((off64_t) (upper + 1) < 0);
if (lseek64 (outfd, upper, SEEK_SET) >= 0)
{
if (write (outfd, "", 1) == 1)
FAIL_EXIT1 ("created a file larger than the off64_t range");
}
uint64_t lower = 1024 * 1024; /* A reasonable minimum file size. */
/* Loop invariant: writing at lower succeeds, writing at upper fails. */
while (lower + 1 < upper)
{
uint64_t middle = (lower + upper) / 2;
if (test_verbose > 0)
printf ("info: %s: remaining test range %" PRIu64 " .. %" PRIu64
", probe at %" PRIu64 "\n", __func__, lower, upper, middle);
xftruncate (outfd, 0);
if (lseek64 (outfd, middle, SEEK_SET) >= 0
&& write (outfd, "", 1) == 1)
lower = middle;
else
upper = middle;
}
TEST_VERIFY (lower + 1 == upper);
maximum_offset = lower;
printf ("info: maximum writable file offset: %" PRIu64 " (%" PRIx64 ")\n",
lower, lower);
/* Check that writing at the valid offset actually works. */
xftruncate (outfd, 0);
xlseek (outfd, lower, SEEK_SET);
TEST_COMPARE (write (outfd, "", 1), 1);
/* Cross the boundary with a two-byte write. This can either result
in a short write, or a failure. */
xlseek (outfd, lower, SEEK_SET);
ssize_t ret = write (outfd, " ", 2);
if (ret < 0)
{
maximum_offset_errno = errno;
maximum_offset_hard_limit = true;
}
else
maximum_offset_hard_limit = false;
/* Check that writing at the next offset actually fails. This also
obtains the expected errno value. */
xftruncate (outfd, 0);
const char *action;
if (lseek64 (outfd, lower + 1, SEEK_SET) != 0)
{
if (write (outfd, "", 1) != -1)
FAIL_EXIT1 ("write to impossible offset %" PRIu64 " succeeded",
lower + 1);
action = "writing";
int errno_copy = errno;
if (maximum_offset_hard_limit)
TEST_COMPARE (errno_copy, maximum_offset_errno);
else
maximum_offset_errno = errno_copy;
}
else
{
action = "seeking";
maximum_offset_errno = errno;
}
printf ("info: %s out of range fails with %m (%d)\n",
action, maximum_offset_errno);
xftruncate (outfd, 0);
xlseek (outfd, 0, SEEK_SET);
}
/* Perform a copy of a file. */
static void
simple_file_copy (void)
@ -247,390 +138,6 @@ simple_file_copy (void)
free (bytes);
}
/* Test that reading from a pipe willfails. */
static void
pipe_as_source (void)
{
int pipefds[2];
xpipe (pipefds);
for (int length = 0; length < 2; ++length)
{
if (test_verbose > 0)
printf ("info: %s: length=%d\n", __func__, length);
/* Make sure that there is something to copy in the pipe. */
xwrite (pipefds[1], "@", 1);
TEST_COMPARE (copy_file_range (pipefds[0], pinoff, outfd, poutoff,
length, 0), -1);
/* Linux 4.10 and later return EINVAL. Older kernels return
EXDEV. */
TEST_VERIFY (errno == EINVAL || errno == EXDEV);
TEST_COMPARE (inoff, 0);
TEST_COMPARE (outoff, 0);
TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 0);
/* Make sure that nothing was read. */
char buf = 'A';
TEST_COMPARE (read (pipefds[0], &buf, 1), 1);
TEST_COMPARE (buf, '@');
}
xclose (pipefds[0]);
xclose (pipefds[1]);
}
/* Test that writing to a pipe fails. */
static void
pipe_as_destination (void)
{
/* Make sure that there is something to read in the input file. */
xwrite (infd, "abc", 3);
xlseek (infd, 0, SEEK_SET);
int pipefds[2];
xpipe (pipefds);
for (int length = 0; length < 2; ++length)
{
if (test_verbose > 0)
printf ("info: %s: length=%d\n", __func__, length);
TEST_COMPARE (copy_file_range (infd, pinoff, pipefds[1], poutoff,
length, 0), -1);
/* Linux 4.10 and later return EINVAL. Older kernels return
EXDEV. */
TEST_VERIFY (errno == EINVAL || errno == EXDEV);
TEST_COMPARE (inoff, 0);
TEST_COMPARE (outoff, 0);
TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);
/* Make sure that nothing was written. */
struct pollfd pollfd = { .fd = pipefds[0], .events = POLLIN, };
TEST_COMPARE (poll (&pollfd, 1, 0), 0);
}
xclose (pipefds[0]);
xclose (pipefds[1]);
}
/* Test a write failure after (potentially) writing some bytes.
Failure occurs near the start of the buffer. */
static void
delayed_write_failure_beginning (void)
{
/* We need to write something to provoke the error. */
if (current_size == 0)
return;
xwrite (infd, random_data, sizeof (random_data));
xlseek (infd, 0, SEEK_SET);
/* Write failure near the start. The actual error code varies among
file systems. */
find_maximum_offset ();
off64_t where = maximum_offset;
if (current_size == 1)
++where;
outoff = where;
if (do_outoff)
xlseek (outfd, 1, SEEK_SET);
else
xlseek (outfd, where, SEEK_SET);
if (maximum_offset_hard_limit || where > maximum_offset)
{
TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
sizeof (random_data), 0), -1);
TEST_COMPARE (errno, maximum_offset_errno);
TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);
TEST_COMPARE (inoff, 0);
if (do_outoff)
TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 1);
else
TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), where);
TEST_COMPARE (outoff, where);
struct stat64 st;
xfstat (outfd, &st);
TEST_COMPARE (st.st_size, 0);
}
else
{
/* The offset is not a hard limit. This means we write one
byte. */
TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
sizeof (random_data), 0), 1);
if (do_inoff)
{
TEST_COMPARE (inoff, 1);
TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);
}
else
{
TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 1);
TEST_COMPARE (inoff, 0);
}
if (do_outoff)
{
TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 1);
TEST_COMPARE (outoff, where + 1);
}
else
{
TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), where + 1);
TEST_COMPARE (outoff, where);
}
struct stat64 st;
xfstat (outfd, &st);
TEST_COMPARE (st.st_size, where + 1);
}
}
/* Test a write failure after (potentially) writing some bytes.
Failure occurs near the end of the buffer. */
static void
delayed_write_failure_end (void)
{
if (current_size <= 1)
/* This would be same as the first test because there is not
enough data to write to make a difference. */
return;
xwrite (infd, random_data, sizeof (random_data));
xlseek (infd, 0, SEEK_SET);
find_maximum_offset ();
off64_t where = maximum_offset - current_size + 1;
if (current_size == sizeof (random_data))
/* Otherwise we do not reach the non-writable byte. */
++where;
outoff = where;
if (do_outoff)
xlseek (outfd, 1, SEEK_SET);
else
xlseek (outfd, where, SEEK_SET);
ssize_t ret = copy_file_range (infd, pinoff, outfd, poutoff,
sizeof (random_data), 0);
if (ret < 0)
{
TEST_COMPARE (ret, -1);
TEST_COMPARE (errno, maximum_offset_errno);
struct stat64 st;
xfstat (outfd, &st);
TEST_COMPARE (st.st_size, 0);
}
else
{
/* The first copy succeeded. This happens in the emulation
because the internal buffer of limited size does not
necessarily cross the off64_t boundary on the first write
operation. */
if (test_verbose > 0)
printf ("info: copy_file_range (%zu) returned %zd\n",
sizeof (random_data), ret);
TEST_VERIFY (ret > 0);
TEST_VERIFY (ret < maximum_size);
struct stat64 st;
xfstat (outfd, &st);
TEST_COMPARE (st.st_size, where + ret);
if (do_inoff)
{
TEST_COMPARE (inoff, ret);
TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);
}
else
TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), ret);
char *buffer = xmalloc (ret);
TEST_COMPARE (pread64 (outfd, buffer, ret, where), ret);
TEST_VERIFY (memcmp (buffer, random_data, ret) == 0);
free (buffer);
/* The second copy fails. */
TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
sizeof (random_data), 0), -1);
TEST_COMPARE (errno, maximum_offset_errno);
}
}
/* Test a write failure across devices. */
static void
cross_device_failure (void)
{
if (xdevfile == NULL)
/* Subtest not supported due to missing cross-device file. */
return;
/* We need something to write. */
xwrite (infd, random_data, sizeof (random_data));
xlseek (infd, 0, SEEK_SET);
int xdevfd = xopen (xdevfile, O_RDWR | O_LARGEFILE, 0);
TEST_COMPARE (copy_file_range (infd, pinoff, xdevfd, poutoff,
current_size, 0), -1);
TEST_COMPARE (errno, EXDEV);
TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 0);
struct stat64 st;
xfstat (xdevfd, &st);
TEST_COMPARE (st.st_size, 0);
xclose (xdevfd);
}
/* Try to exercise ENOSPC behavior with a tempfs file system (so that
we do not have to fill up a regular file system to get the error).
This function runs in a subprocess, so that we do not change the
mount namespace of the actual test process. */
static void
enospc_failure_1 (void *closure)
{
#ifdef CLONE_NEWNS
support_become_root ();
/* Make sure that we do not alter the file system mounts of the
parents. */
if (! support_enter_mount_namespace ())
{
printf ("warning: ENOSPC test skipped\n");
return;
}
char *mountpoint = closure;
if (mount ("none", mountpoint, "tmpfs", MS_NODEV | MS_NOEXEC,
"size=500k") != 0)
{
printf ("warning: could not mount tmpfs at %s: %m\n", mountpoint);
return;
}
/* The source file must reside on the same file system. */
char *intmpfsfile = xasprintf ("%s/%s", mountpoint, "in");
int intmpfsfd = xopen (intmpfsfile, O_RDWR | O_CREAT | O_LARGEFILE, 0600);
xwrite (intmpfsfd, random_data, sizeof (random_data));
xlseek (intmpfsfd, 1, SEEK_SET);
inoff = 1;
char *outtmpfsfile = xasprintf ("%s/%s", mountpoint, "out");
int outtmpfsfd = xopen (outtmpfsfile, O_RDWR | O_CREAT | O_LARGEFILE, 0600);
/* Fill the file with data until ENOSPC is reached. */
while (true)
{
ssize_t ret = write (outtmpfsfd, random_data, sizeof (random_data));
if (ret < 0 && errno != ENOSPC)
FAIL_EXIT1 ("write to %s: %m", outtmpfsfile);
if (ret < sizeof (random_data))
break;
}
TEST_COMPARE (write (outtmpfsfd, "", 1), -1);
TEST_COMPARE (errno, ENOSPC);
off64_t maxsize = xlseek (outtmpfsfd, 0, SEEK_CUR);
TEST_VERIFY_EXIT (maxsize > sizeof (random_data));
/* Constructed the expected file contents. */
char *expected = xmalloc (maxsize);
TEST_COMPARE (pread64 (outtmpfsfd, expected, maxsize, 0), maxsize);
/* Go back a little, so some bytes can be written. */
enum { offset = 20000 };
TEST_VERIFY_EXIT (offset < maxsize);
TEST_VERIFY_EXIT (offset < sizeof (random_data));
memcpy (expected + maxsize - offset, random_data + 1, offset);
if (do_outoff)
{
outoff = maxsize - offset;
xlseek (outtmpfsfd, 2, SEEK_SET);
}
else
xlseek (outtmpfsfd, -offset, SEEK_CUR);
/* First call is expected to succeed because we made room for some
bytes. */
TEST_COMPARE (copy_file_range (intmpfsfd, pinoff, outtmpfsfd, poutoff,
maximum_size, 0), offset);
if (do_inoff)
{
TEST_COMPARE (inoff, 1 + offset);
TEST_COMPARE (xlseek (intmpfsfd, 0, SEEK_CUR), 1);
}
else
TEST_COMPARE (xlseek (intmpfsfd, 0, SEEK_CUR), 1 + offset);
if (do_outoff)
{
TEST_COMPARE (outoff, maxsize);
TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_CUR), 2);
}
else
TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_CUR), maxsize);
struct stat64 st;
xfstat (outtmpfsfd, &st);
TEST_COMPARE (st.st_size, maxsize);
char *actual = xmalloc (st.st_size);
TEST_COMPARE (pread64 (outtmpfsfd, actual, st.st_size, 0), st.st_size);
TEST_VERIFY (memcmp (expected, actual, maxsize) == 0);
/* Second call should fail with ENOSPC. */
TEST_COMPARE (copy_file_range (intmpfsfd, pinoff, outtmpfsfd, poutoff,
maximum_size, 0), -1);
TEST_COMPARE (errno, ENOSPC);
/* Offsets should be unchanged. */
if (do_inoff)
{
TEST_COMPARE (inoff, 1 + offset);
TEST_COMPARE (xlseek (intmpfsfd, 0, SEEK_CUR), 1);
}
else
TEST_COMPARE (xlseek (intmpfsfd, 0, SEEK_CUR), 1 + offset);
if (do_outoff)
{
TEST_COMPARE (outoff, maxsize);
TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_CUR), 2);
}
else
TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_CUR), maxsize);
TEST_COMPARE (xlseek (outtmpfsfd, 0, SEEK_END), maxsize);
TEST_COMPARE (pread64 (outtmpfsfd, actual, maxsize, 0), maxsize);
TEST_VERIFY (memcmp (expected, actual, maxsize) == 0);
free (actual);
free (expected);
xclose (intmpfsfd);
xclose (outtmpfsfd);
free (intmpfsfile);
free (outtmpfsfile);
#else /* !CLONE_NEWNS */
puts ("warning: ENOSPC test skipped (no mount namespaces)");
#endif
}
/* Call enospc_failure_1 in a subprocess. */
static void
enospc_failure (void)
{
char *mountpoint
= support_create_temp_directory ("tst-copy_file_range-enospc-");
support_isolate_in_subprocess (enospc_failure_1, mountpoint);
free (mountpoint);
}
/* The target file descriptor must have O_APPEND enabled. */
static void
oappend_failure (void)
{
/* Add data, to make sure we do not fail because there is
insufficient input data. */
xwrite (infd, random_data, current_size);
xlseek (infd, 0, SEEK_SET);
xclose (outfd);
outfd = xopen (outfile, O_RDWR | O_APPEND, 0);
TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
current_size, 0), -1);
TEST_COMPARE (errno, EBADF);
}
/* Test that a short input file results in a shortened copy. */
static void
short_copy (void)
@ -721,14 +228,6 @@ struct test_case
static struct test_case tests[] =
{
{ "simple_file_copy", simple_file_copy, .sizes = true },
{ "pipe_as_source", pipe_as_source, },
{ "pipe_as_destination", pipe_as_destination, },
{ "delayed_write_failure_beginning", delayed_write_failure_beginning,
.sizes = true },
{ "delayed_write_failure_end", delayed_write_failure_end, .sizes = true },
{ "cross_device_failure", cross_device_failure, .sizes = true },
{ "enospc_failure", enospc_failure, },
{ "oappend_failure", oappend_failure, .sizes = true },
{ "short_copy", short_copy, .sizes = true },
};
@ -739,53 +238,18 @@ do_test (void)
*p = rand () >> 24;
infd = create_temp_file ("tst-copy_file_range-in-", &infile);
xclose (create_temp_file ("tst-copy_file_range-out-", &outfile));
/* Try to find a different directory from the default input/output
file. */
outfd = create_temp_file ("tst-copy_file_range-out-", &outfile);
{
struct stat64 instat;
xfstat (infd, &instat);
static const char *const candidates[] =
{ NULL, "/var/tmp", "/dev/shm" };
for (const char *const *c = candidates; c < array_end (candidates); ++c)
ssize_t ret = copy_file_range (infd, NULL, outfd, NULL, 0, 0);
if (ret != 0)
{
const char *path = *c;
char *to_free = NULL;
if (path == NULL)
{
to_free = xreadlink ("/proc/self/exe");
path = dirname (to_free);
}
struct stat64 cstat;
xstat (path, &cstat);
if (cstat.st_dev == instat.st_dev)
{
free (to_free);
continue;
}
printf ("info: using alternate temporary files directory: %s\n", path);
xdevfile = xasprintf ("%s/tst-copy_file_range-xdev-XXXXXX", path);
free (to_free);
break;
if (errno == ENOSYS)
FAIL_UNSUPPORTED ("copy_file_range is not support on this system");
FAIL_EXIT1 ("copy_file_range probing call: %m");
}
if (xdevfile != NULL)
{
int xdevfd = mkstemp (xdevfile);
if (xdevfd < 0)
FAIL_EXIT1 ("mkstemp (\"%s\"): %m", xdevfile);
struct stat64 xdevst;
xfstat (xdevfd, &xdevst);
TEST_VERIFY (xdevst.st_dev != instat.st_dev);
add_temp_file (xdevfile);
xclose (xdevfd);
}
else
puts ("warning: no alternate directory on different file system found");
}
xclose (infd);
xclose (outfd);
for (do_inoff = 0; do_inoff < 2; ++do_inoff)
for (do_outoff = 0; do_outoff < 2; ++do_outoff)
@ -827,7 +291,6 @@ do_test (void)
free (infile);
free (outfile);
free (xdevfile);
return 0;
}

10
manual/llio.texi
View File

@ -1404,10 +1404,13 @@ failure occurs. The return value is zero if the end of the input file
is encountered immediately.
If no bytes can be copied, to report an error, @code{copy_file_range}
returns the value @math{-1} and sets @code{errno}. The following
@code{errno} error conditions are specific to this function:
returns the value @math{-1} and sets @code{errno}. The table below
lists some of the error conditions for this function.
@table @code
@item ENOSYS
The kernel does not implement the required functionality.
@item EISDIR
At least one of the descriptors @var{inputfd} or @var{outputfd} refers
to a directory.
@ -1437,9 +1440,6 @@ reading.
The argument @var{outputfd} is not a valid file descriptor open for
writing, or @var{outputfd} has been opened with @code{O_APPEND}.
@item EXDEV
The input and output files reside on different file systems.
@end table
In addition, @code{copy_file_range} can fail with the error codes

1
sysdeps/unix/sysv/linux/alpha/kernel-features.h
View File

@ -48,7 +48,6 @@
/* Support for copy_file_range, statx was added in kernel 4.13. */
#if __LINUX_KERNEL_VERSION < 0x040D00
# undef __ASSUME_MLOCK2
# undef __ASSUME_COPY_FILE_RANGE
# undef __ASSUME_STATX
#endif

21
sysdeps/unix/sysv/linux/copy_file_range.c
View File

@ -20,27 +20,16 @@
#include <sysdep-cancel.h>
#include <unistd.h>
/* Include the fallback implementation. */
#ifndef __ASSUME_COPY_FILE_RANGE
#define COPY_FILE_RANGE_DECL static
#define COPY_FILE_RANGE copy_file_range_compat
#include <io/copy_file_range-compat.c>
#endif
ssize_t
copy_file_range (int infd, __off64_t *pinoff,
int outfd, __off64_t *poutoff,
size_t length, unsigned int flags)
{
#ifdef __NR_copy_file_range
ssize_t ret = SYSCALL_CANCEL (copy_file_range, infd, pinoff, outfd, poutoff,
length, flags);
# ifndef __ASSUME_COPY_FILE_RANGE
if (ret == -1 && errno == ENOSYS)
ret = copy_file_range_compat (infd, pinoff, outfd, poutoff, length, flags);
# endif
return ret;
#else /* !__NR_copy_file_range */
return copy_file_range_compat (infd, pinoff, outfd, poutoff, length, flags);
return SYSCALL_CANCEL (copy_file_range, infd, pinoff, outfd, poutoff,
length, flags);
#else
__set_errno (ENOSYS);
return -1;
#endif
}

4
sysdeps/unix/sysv/linux/kernel-features.h
View File

@ -111,10 +111,6 @@
# define __ASSUME_MLOCK2 1
#endif
#if __LINUX_KERNEL_VERSION >= 0x040500
# define __ASSUME_COPY_FILE_RANGE 1
#endif
/* Support for statx was added in kernel 4.11. */
#if __LINUX_KERNEL_VERSION >= 0x040B00
# define __ASSUME_STATX 1

3
sysdeps/unix/sysv/linux/microblaze/kernel-features.h
View File

@ -58,9 +58,6 @@
# undef __ASSUME_EXECVEAT
#endif
/* Support for the copy_file_range syscall was added in 4.10. */
#if __LINUX_KERNEL_VERSION < 0x040A00
# undef __ASSUME_COPY_FILE_RANGE
#endif
/* Support for statx was added in kernel 4.12. */