s3: add vfs_crossrename

this module adds optional server-side support for limited rename operations
beyond filesystem boundaries, which was the previously the default.

1 files changed, 200 insertions, 0 deletions

diff --git a/source3/modules/vfs_crossrename.c b/source3/modules/vfs_crossrename.c
new file mode 100644
index 0000000000..323ceb120b
--- /dev/null
+++ b/source3/modules/vfs_crossrename.c
@@ -0,0 +1,200 @@
+/*
+ * Copyright (c) Björn Jacke 2010
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+#include "includes.h"
+
+
+#define MODULE "crossrename"
+static SMB_OFF_T module_sizelimit;
+
+static int crossrename_connect(
+                struct vfs_handle_struct *  handle,
+                const char *                service,
+                const char *                user)
+{
+	int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
+
+	if (ret < 0) {
+		return ret;
+	}
+
+	module_sizelimit = (SMB_OFF_T) lp_parm_int(SNUM(handle->conn),
+					MODULE, "sizelimit", 20);
+	/* convert from MiB to byte: */
+	module_sizelimit *= 1048576;
+
+	return 0;
+}
+
+/*********************************************************
+ For rename across filesystems initial Patch from Warren Birnbaum
+ <warrenb@hpcvscdp.cv.hp.com>
+**********************************************************/
+
+static int copy_reg(const char *source, const char *dest)
+{
+	SMB_STRUCT_STAT source_stats;
+	int saved_errno;
+	int ifd = -1;
+	int ofd = -1;
+
+	if (sys_lstat(source, &source_stats, false) == -1)
+		return -1;
+
+	if (!S_ISREG (source_stats.st_ex_mode))
+		return -1;
+
+	if (source_stats.st_ex_size > module_sizelimit) {
+		DEBUG(5,
+			("%s: size of %s larger than sizelimit (%lld > %lld), rename prohititted\n",
+			MODULE, source,
+			(long long)source_stats.st_ex_size,
+			(long long)module_sizelimit));
+		return -1;
+	}
+
+	if((ifd = sys_open (source, O_RDONLY, 0)) < 0)
+		return -1;
+
+	if (unlink (dest) && errno != ENOENT)
+		return -1;
+
+#ifdef O_NOFOLLOW
+	if((ofd = sys_open (dest, O_WRONLY | O_CREAT | O_TRUNC | O_NOFOLLOW, 0600)) < 0 )
+#else
+	if((ofd = sys_open (dest, O_WRONLY | O_CREAT | O_TRUNC , 0600)) < 0 )
+#endif
+		goto err;
+
+	if (transfer_file(ifd, ofd, (size_t)-1) == -1)
+		goto err;
+
+	/*
+	 * Try to preserve ownership.  For non-root it might fail, but that's ok.
+	 * But root probably wants to know, e.g. if NFS disallows it.
+	 */
+
+#ifdef HAVE_FCHOWN
+	if ((fchown(ofd, source_stats.st_ex_uid, source_stats.st_ex_gid) == -1) && (errno != EPERM))
+#else
+	if ((chown(dest, source_stats.st_ex_uid, source_stats.st_ex_gid) == -1) && (errno != EPERM))
+#endif
+		goto err;
+
+	/*
+	 * fchown turns off set[ug]id bits for non-root,
+	 * so do the chmod last.
+	 */
+
+#if defined(HAVE_FCHMOD)
+	if (fchmod (ofd, source_stats.st_ex_mode & 07777))
+#else
+	if (chmod (dest, source_stats.st_ex_mode & 07777))
+#endif
+		goto err;
+
+	if (close (ifd) == -1)
+		goto err;
+
+	if (close (ofd) == -1)
+		return -1;
+
+	/* Try to copy the old file's modtime and access time.  */
+#if defined(HAVE_UTIMENSAT)
+	{
+		struct timespec ts[2];
+
+		ts[0] = source_stats.st_ex_atime;
+		ts[1] = source_stats.st_ex_mtime;
+		utimensat(AT_FDCWD, dest, ts, AT_SYMLINK_NOFOLLOW);
+	}
+#elif defined(HAVE_UTIMES)
+	{
+		struct timeval tv[2];
+
+		tv[0] = convert_timespec_to_timeval(source_stats.st_ex_atime);
+		tv[1] = convert_timespec_to_timeval(source_stats.st_ex_mtime);
+#ifdef HAVE_LUTIMES
+		lutimes(dest, tv);
+#else
+		utimes(dest, tv);
+#endif
+	}
+#elif defined(HAVE_UTIME)
+	{
+		struct utimbuf tv;
+
+		tv.actime = convert_timespec_to_time_t(source_stats.st_ex_atime);
+		tv.modtime = convert_timespec_to_time_t(source_stats.st_ex_mtime);
+		utime(dest, &tv);
+	}
+#endif
+
+	if (unlink (source) == -1)
+		return -1;
+
+	return 0;
+
+  err:
+
+	saved_errno = errno;
+	if (ifd != -1)
+		close(ifd);
+	if (ofd != -1)
+		close(ofd);
+	errno = saved_errno;
+	return -1;
+}
+
+
+static int crossrename_rename(vfs_handle_struct *handle,
+			  const struct smb_filename *smb_fname_src,
+			  const struct smb_filename *smb_fname_dst)
+{
+	int result = -1;
+
+	START_PROFILE(syscall_rename);
+
+	if (smb_fname_src->stream_name || smb_fname_dst->stream_name) {
+		errno = ENOENT;
+		goto out;
+	}
+
+	result = rename(smb_fname_src->base_name, smb_fname_dst->base_name);
+	if ((result == -1) && (errno == EXDEV)) {
+		/* Rename across filesystems needed. */
+		result = copy_reg(smb_fname_src->base_name,
+				  smb_fname_dst->base_name);
+	}
+
+ out:
+	END_PROFILE(syscall_rename);
+	return result;
+}
+
+static struct vfs_fn_pointers vfs_crossrename_fns = {
+	.connect_fn = crossrename_connect,
+	.rename = crossrename_rename
+};
+
+NTSTATUS vfs_crossrename_init(void);
+NTSTATUS vfs_crossrename_init(void)
+{
+	return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, MODULE,
+				&vfs_crossrename_fns);
+}
+