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/* Copying of files.
Copyright (C) 2001-2003, 2006-2007, 2009-2023 Free Software Foundation, Inc.
Written by Bruno Haible <haible@clisp.cons.org>, 2001.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "copy-file.h"
#include <errno.h>
#include <fcntl.h>
#include <stddef.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <unistd.h>
#include "error.h"
#include "ignore-value.h"
#include "safe-read.h"
#include "full-write.h"
#include "stat-time.h"
#include "utimens.h"
#include "acl.h"
#include "binary-io.h"
#include "quote.h"
#include "gettext.h"
#define _(str) gettext (str)
enum { IO_SIZE = 32 * 1024 };
int
qcopy_file_preserving (const char *src_filename, const char *dest_filename)
{
int err = 0;
int src_fd;
struct stat statbuf;
int mode;
int dest_fd;
src_fd = open (src_filename, O_RDONLY | O_BINARY | O_CLOEXEC);
if (src_fd < 0)
return GL_COPY_ERR_OPEN_READ;
if (fstat (src_fd, &statbuf) < 0)
{
err = GL_COPY_ERR_OPEN_READ;
goto error_src;
}
mode = statbuf.st_mode & 07777;
off_t inbytes = S_ISREG (statbuf.st_mode) ? statbuf.st_size : -1;
bool empty_regular_file = inbytes == 0;
dest_fd = open (dest_filename,
O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_CLOEXEC,
0600);
if (dest_fd < 0)
{
err = GL_COPY_ERR_OPEN_BACKUP_WRITE;
goto error_src;
}
/* Copy the file contents. FIXME: Do not copy holes. */
while (0 < inbytes)
{
size_t copy_max = -1;
copy_max -= copy_max % IO_SIZE;
size_t len = inbytes < copy_max ? inbytes : copy_max;
ssize_t copied = copy_file_range (src_fd, NULL, dest_fd, NULL, len, 0);
if (copied <= 0)
break;
inbytes -= copied;
}
/* Finish up with read/write, in case the file was not a regular
file, or the file shrank or had I/O errors (in which case find
whether it was a read or write error). Read empty regular files
since they might be in /proc with their true sizes unknown until
they are read. */
if (inbytes != 0 || empty_regular_file)
{
char smallbuf[1024];
int bufsize = IO_SIZE;
char *buf = malloc (bufsize);
if (!buf)
buf = smallbuf, bufsize = sizeof smallbuf;
while (true)
{
size_t n_read = safe_read (src_fd, buf, bufsize);
if (n_read == 0)
break;
if (n_read == SAFE_READ_ERROR)
{
err = GL_COPY_ERR_READ;
break;
}
if (full_write (dest_fd, buf, n_read) < n_read)
{
err = GL_COPY_ERR_WRITE;
break;
}
}
if (buf != smallbuf)
free (buf);
if (err)
goto error_src_dest;
}
#if !USE_ACL
if (close (dest_fd) < 0)
{
err = GL_COPY_ERR_WRITE;
goto error_src;
}
if (close (src_fd) < 0)
return GL_COPY_ERR_AFTER_READ;
#endif
/* Preserve the access and modification times. */
{
struct timespec ts[2];
ts[0] = get_stat_atime (&statbuf);
ts[1] = get_stat_mtime (&statbuf);
utimens (dest_filename, ts);
}
#if HAVE_CHOWN
/* Preserve the owner and group. */
ignore_value (chown (dest_filename, statbuf.st_uid, statbuf.st_gid));
#endif
/* Preserve the access permissions. */
#if USE_ACL
switch (qcopy_acl (src_filename, src_fd, dest_filename, dest_fd, mode))
{
case -2:
err = GL_COPY_ERR_GET_ACL;
goto error_src_dest;
case -1:
err = GL_COPY_ERR_SET_ACL;
goto error_src_dest;
}
#else
chmod (dest_filename, mode);
#endif
#if USE_ACL
if (close (dest_fd) < 0)
{
err = GL_COPY_ERR_WRITE;
goto error_src;
}
if (close (src_fd) < 0)
return GL_COPY_ERR_AFTER_READ;
#endif
return 0;
error_src_dest:
close (dest_fd);
error_src:
close (src_fd);
return err;
}
void
copy_file_preserving (const char *src_filename, const char *dest_filename)
{
switch (qcopy_file_preserving (src_filename, dest_filename))
{
case 0:
return;
case GL_COPY_ERR_OPEN_READ:
error (EXIT_FAILURE, errno, _("error while opening %s for reading"),
quote (src_filename));
case GL_COPY_ERR_OPEN_BACKUP_WRITE:
error (EXIT_FAILURE, errno, _("cannot open backup file %s for writing"),
quote (dest_filename));
case GL_COPY_ERR_READ:
error (EXIT_FAILURE, errno, _("error reading %s"),
quote (src_filename));
case GL_COPY_ERR_WRITE:
error (EXIT_FAILURE, errno, _("error writing %s"),
quote (dest_filename));
case GL_COPY_ERR_AFTER_READ:
error (EXIT_FAILURE, errno, _("error after reading %s"),
quote (src_filename));
case GL_COPY_ERR_GET_ACL:
error (EXIT_FAILURE, errno, "%s", quote (src_filename));
case GL_COPY_ERR_SET_ACL:
error (EXIT_FAILURE, errno, _("preserving permissions for %s"),
quote (dest_filename));
default:
abort ();
}
}
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