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https://github.com/libguestfs/libguestfs.git
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606732d02e
The presumption is that all file descriptors should be created with
the close-on-exec flag set. The only exception are file descriptors
that we want passed through to exec'd subprocesses (mainly pipes and
stdin/stdout/stderr).
For open calls, we pass O_CLOEXEC as an extra flag, eg:
fd = open ("foo", O_RDONLY|O_CLOEXEC);
This is a Linux-ism, but using a macro we can easily make it portable.
For sockets, similarly:
sock = socket (..., SOCK_STREAM|SOCK_CLOEXEC, ...);
For accepted sockets, we use the Linux accept4 system call which
allows flags to be supplied, but we use the Gnulib 'accept4' module to
make this portable.
For dup, dup2, we use the Linux dup3 system call, and the Gnulib
modules 'dup3' and 'cloexec'.
89 lines
2.0 KiB
C
89 lines
2.0 KiB
C
/* libguestfs - the guestfsd daemon
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* Copyright (C) 2009 Red Hat Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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#include "daemon.h"
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#include "actions.h"
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int
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do_fallocate (const char *path, int len)
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{
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if (len < 0) {
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reply_with_error ("length < 0");
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return -1;
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}
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return do_fallocate64 (path, len);
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}
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int
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do_fallocate64 (const char *path, int64_t len)
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{
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int fd;
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CHROOT_IN;
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fd = open (path, O_WRONLY|O_CREAT|O_TRUNC|O_NOCTTY|O_CLOEXEC, 0666);
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CHROOT_OUT;
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if (fd == -1) {
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reply_with_perror ("open: %s", path);
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return -1;
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}
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#ifdef HAVE_POSIX_FALLOCATE
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int err = posix_fallocate (fd, 0, len);
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if (err != 0) {
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errno = err;
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reply_with_perror ("%s", path);
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close (fd);
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return -1;
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}
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#else
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ssize_t r;
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char buf[BUFSIZ];
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const size_t len_sz = (size_t) len;
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size_t n;
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memset (buf, 0, BUFSIZ);
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n = 0;
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while (n < len_sz) {
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r = write (fd, buf, len_sz - n < BUFSIZ ? len_sz - n : BUFSIZ);
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if (r == -1) {
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reply_with_perror ("write: %s", path);
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close (fd);
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return -1;
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}
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n += r;
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}
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#endif
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if (close (fd) == -1) {
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reply_with_perror ("close: %s", path);
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return -1;
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}
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return 0;
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}
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