open.c

samba-3.0.22.tar.gz 编译smb服务器的源码

/* 
   Unix SMB/CIFS implementation.
   file opening and share modes
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Jeremy Allison 2001-2004
   Copyright (C) Volker Lendecke 2005
   
   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 2 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

extern struct current_user current_user;
extern userdom_struct current_user_info;
extern uint16 global_smbpid;
extern BOOL global_client_failed_oplock_break;

struct deferred_open_record {
	BOOL delayed_for_oplocks;
	SMB_DEV_T dev;
	SMB_INO_T inode;
};

/****************************************************************************
 fd support routines - attempt to do a dos_open.
****************************************************************************/

static int fd_open(struct connection_struct *conn,
			const char *fname, 
			int flags,
			mode_t mode)
{
	int fd;
#ifdef O_NOFOLLOW
	if (!lp_symlinks(SNUM(conn))) {
		flags |= O_NOFOLLOW;
	}
#endif

	fd = SMB_VFS_OPEN(conn,fname,flags,mode);

	DEBUG(10,("fd_open: name %s, flags = 0%o mode = 0%o, fd = %d. %s\n", fname,
		flags, (int)mode, fd, (fd == -1) ? strerror(errno) : "" ));

	return fd;
}

/****************************************************************************
 Close the file associated with a fsp.
****************************************************************************/

int fd_close(struct connection_struct *conn,
		files_struct *fsp)
{
	if (fsp->fh->fd == -1) {
		return 0; /* What we used to call a stat open. */
	}
	if (fsp->fh->ref_count > 1) {
		return 0; /* Shared handle. Only close last reference. */
	}
	return fd_close_posix(conn, fsp);
}

/****************************************************************************
 Change the ownership of a file to that of the parent directory.
 Do this by fd if possible.
****************************************************************************/

void change_owner_to_parent(connection_struct *conn,
				files_struct *fsp,
				const char *fname,
				SMB_STRUCT_STAT *psbuf)
{
	const char *parent_path = parent_dirname(fname);
	SMB_STRUCT_STAT parent_st;
	int ret;

	ret = SMB_VFS_STAT(conn, parent_path, &parent_st);
	if (ret == -1) {
		DEBUG(0,("change_owner_to_parent: failed to stat parent "
			 "directory %s. Error was %s\n",
			 parent_path, strerror(errno) ));
		return;
	}

	if (fsp && fsp->fh->fd != -1) {
		become_root();
		ret = SMB_VFS_FCHOWN(fsp, fsp->fh->fd, parent_st.st_uid, (gid_t)-1);
		unbecome_root();
		if (ret == -1) {
			DEBUG(0,("change_owner_to_parent: failed to fchown "
				 "file %s to parent directory uid %u. Error "
				 "was %s\n", fname,
				 (unsigned int)parent_st.st_uid,
				 strerror(errno) ));
		}

		DEBUG(10,("change_owner_to_parent: changed new file %s to "
			  "parent directory uid %u.\n",	fname,
			  (unsigned int)parent_st.st_uid ));

	} else {
		/* We've already done an lstat into psbuf, and we know it's a
		   directory. If we can cd into the directory and the dev/ino
		   are the same then we can safely chown without races as
		   we're locking the directory in place by being in it.  This
		   should work on any UNIX (thanks tridge :-). JRA.
		*/

		pstring saved_dir;
		SMB_STRUCT_STAT sbuf;

		if (!vfs_GetWd(conn,saved_dir)) {
			DEBUG(0,("change_owner_to_parent: failed to get "
				 "current working directory\n"));
			return;
		}

		/* Chdir into the new path. */
		if (vfs_ChDir(conn, fname) == -1) {
			DEBUG(0,("change_owner_to_parent: failed to change "
				 "current working directory to %s. Error "
				 "was %s\n", fname, strerror(errno) ));
			goto out;
		}

		if (SMB_VFS_STAT(conn,".",&sbuf) == -1) {
			DEBUG(0,("change_owner_to_parent: failed to stat "
				 "directory '.' (%s) Error was %s\n",
				 fname, strerror(errno)));
			goto out;
		}

		/* Ensure we're pointing at the same place. */
		if (sbuf.st_dev != psbuf->st_dev ||
		    sbuf.st_ino != psbuf->st_ino ||
		    sbuf.st_mode != psbuf->st_mode ) {
			DEBUG(0,("change_owner_to_parent: "
				 "device/inode/mode on directory %s changed. "
				 "Refusing to chown !\n", fname ));
			goto out;
		}

		become_root();
		ret = SMB_VFS_CHOWN(conn, ".", parent_st.st_uid, (gid_t)-1);
		unbecome_root();
		if (ret == -1) {
			DEBUG(10,("change_owner_to_parent: failed to chown "
				  "directory %s to parent directory uid %u. "
				  "Error was %s\n", fname,
				  (unsigned int)parent_st.st_uid, strerror(errno) ));
			goto out;
		}

		DEBUG(10,("change_owner_to_parent: changed ownership of new "
			  "directory %s to parent directory uid %u.\n",
			  fname, (unsigned int)parent_st.st_uid ));

  out:

		vfs_ChDir(conn,saved_dir);
	}
}

/****************************************************************************
 Open a file.
****************************************************************************/

static BOOL open_file(files_struct *fsp,
			connection_struct *conn,
			const char *fname,
			SMB_STRUCT_STAT *psbuf,
			int flags,
			mode_t unx_mode,
			uint32 access_mask)
{
	int accmode = (flags & O_ACCMODE);
	int local_flags = flags;
	BOOL file_existed = VALID_STAT(*psbuf);

	fsp->fh->fd = -1;
	errno = EPERM;

	/* Check permissions */

	/*
	 * This code was changed after seeing a client open request 
	 * containing the open mode of (DENY_WRITE/read-only) with
	 * the 'create if not exist' bit set. The previous code
	 * would fail to open the file read only on a read-only share
	 * as it was checking the flags parameter  directly against O_RDONLY,
	 * this was failing as the flags parameter was set to O_RDONLY|O_CREAT.
	 * JRA.
	 */

	if (!CAN_WRITE(conn)) {
		/* It's a read-only share - fail if we wanted to write. */
		if(accmode != O_RDONLY) {
			DEBUG(3,("Permission denied opening %s\n",fname));
			return False;
		} else if(flags & O_CREAT) {
			/* We don't want to write - but we must make sure that
			   O_CREAT doesn't create the file if we have write
			   access into the directory.
			*/
			flags &= ~O_CREAT;
			local_flags &= ~O_CREAT;
		}
	}

	/*
	 * This little piece of insanity is inspired by the
	 * fact that an NT client can open a file for O_RDONLY,
	 * but set the create disposition to FILE_EXISTS_TRUNCATE.
	 * If the client *can* write to the file, then it expects to
	 * truncate the file, even though it is opening for readonly.
	 * Quicken uses this stupid trick in backup file creation...
	 * Thanks *greatly* to "David W. Chapman Jr." <[e-mail]>
	 * for helping track this one down. It didn't bite us in 2.0.x
	 * as we always opened files read-write in that release. JRA.
	 */

	if ((accmode == O_RDONLY) && ((flags & O_TRUNC) == O_TRUNC)) {
		DEBUG(10,("open_file: truncate requested on read-only open "
			  "for file %s\n",fname ));
		local_flags = (flags & ~O_ACCMODE)|O_RDWR;
	}

	if ((access_mask & (FILE_READ_DATA|FILE_WRITE_DATA|FILE_APPEND_DATA|FILE_EXECUTE)) ||
	    (local_flags & O_CREAT) ||
	    ((local_flags & O_TRUNC) == O_TRUNC) ) {

		/*
		 * We can't actually truncate here as the file may be locked.
		 * open_file_shared will take care of the truncate later. JRA.
		 */

		local_flags &= ~O_TRUNC;

#if defined(O_NONBLOCK) && defined(S_ISFIFO)
		/*
		 * We would block on opening a FIFO with no one else on the
		 * other end. Do what we used to do and add O_NONBLOCK to the
		 * open flags. JRA.
		 */

		if (file_existed && S_ISFIFO(psbuf->st_mode)) {
			local_flags |= O_NONBLOCK;
		}
#endif

		/* Don't create files with Microsoft wildcard characters. */
		if ((local_flags & O_CREAT) && !file_existed &&
		    ms_has_wild(fname))  {
			set_saved_ntstatus(NT_STATUS_OBJECT_NAME_INVALID);
			return False;
		}

		/* Actually do the open */
		fsp->fh->fd = fd_open(conn, fname, local_flags, unx_mode);
		if (fsp->fh->fd == -1)  {
			DEBUG(3,("Error opening file %s (%s) (local_flags=%d) "
				 "(flags=%d)\n",
				 fname,strerror(errno),local_flags,flags));
			return False;
		}

		/* Inherit the ACL if the file was created. */
		if ((local_flags & O_CREAT) && !file_existed) {
			inherit_access_acl(conn, fname, unx_mode);
		}

	} else {
		fsp->fh->fd = -1; /* What we used to call a stat open. */
	}

	if (!file_existed) {
		int ret;

		if (fsp->fh->fd == -1) {
			ret = SMB_VFS_STAT(conn, fname, psbuf);
		} else {
			ret = SMB_VFS_FSTAT(fsp,fsp->fh->fd,psbuf);
			/* If we have an fd, this stat should succeed. */
			if (ret == -1) {
				DEBUG(0,("Error doing fstat on open file %s "
					 "(%s)\n", fname,strerror(errno) ));
			}
		}

		/* For a non-io open, this stat failing means file not found. JRA */
		if (ret == -1) {
			fd_close(conn, fsp);
			return False;
		}
	}

	/*
	 * POSIX allows read-only opens of directories. We don't
	 * want to do this (we use a different code path for this)
	 * so catch a directory open and return an EISDIR. JRA.
	 */

	if(S_ISDIR(psbuf->st_mode)) {
		fd_close(conn, fsp);
		errno = EISDIR;
		return False;
	}

	fsp->mode = psbuf->st_mode;
	fsp->inode = psbuf->st_ino;
	fsp->dev = psbuf->st_dev;
	fsp->vuid = current_user.vuid;
	fsp->file_pid = global_smbpid;
	fsp->can_lock = True;
	fsp->can_read = (access_mask & (FILE_READ_DATA)) ? True : False;
	if (!CAN_WRITE(conn)) {
		fsp->can_write = False;
	} else {
		fsp->can_write = (access_mask & (FILE_WRITE_DATA | FILE_APPEND_DATA)) ? True : False;
	}
	fsp->print_file = False;
	fsp->modified = False;
	fsp->sent_oplock_break = NO_BREAK_SENT;
	fsp->is_directory = False;
	fsp->is_stat = False;
	if (conn->aio_write_behind_list &&
	    is_in_path(fname, conn->aio_write_behind_list, conn->case_sensitive)) {
		fsp->aio_write_behind = True;
	}

	string_set(&fsp->fsp_name,fname);
	fsp->wcp = NULL; /* Write cache pointer. */

	DEBUG(2,("%s opened file %s read=%s write=%s (numopen=%d)\n",
		 *current_user_info.smb_name ? current_user_info.smb_name : conn->user,fsp->fsp_name,
		 BOOLSTR(fsp->can_read), BOOLSTR(fsp->can_write),
		 conn->num_files_open + 1));

	errno = 0;
	return True;
}

/*******************************************************************
 Return True if the filename is one of the special executable types.
********************************************************************/

static BOOL is_executable(const char *fname)
{
	if ((fname = strrchr_m(fname,'.'))) {
		if (strequal(fname,".com") ||
		    strequal(fname,".dll") ||
		    strequal(fname,".exe") ||
		    strequal(fname,".sym")) {
			return True;
		}
	}
	return False;
}

/****************************************************************************
 Check if we can open a file with a share mode.
 Returns True if conflict, False if not.
****************************************************************************/

static BOOL share_conflict(struct share_mode_entry *entry,
			   uint32 access_mask,
			   uint32 share_access)
{
	DEBUG(10,("share_conflict: entry->access_mask = 0x%x, "
		  "entry->share_access = 0x%x, "
		  "entry->private_options = 0x%x\n",
		  (unsigned int)entry->access_mask,
		  (unsigned int)entry->share_access,
		  (unsigned int)entry->private_options));

	DEBUG(10,("share_conflict: access_mask = 0x%x, share_access = 0x%x\n",
		  (unsigned int)access_mask, (unsigned int)share_access));

	if ((entry->access_mask & (FILE_WRITE_DATA|
				   FILE_APPEND_DATA|
				   FILE_READ_DATA|
				   FILE_EXECUTE|
				   DELETE_ACCESS)) == 0) {
		DEBUG(10,("share_conflict: No conflict due to "
			  "entry->access_mask = 0x%x\n",
			  (unsigned int)entry->access_mask ));
		return False;
	}

	if ((access_mask & (FILE_WRITE_DATA|
			    FILE_APPEND_DATA|
			    FILE_READ_DATA|
			    FILE_EXECUTE|
			    DELETE_ACCESS)) == 0) {
		DEBUG(10,("share_conflict: No conflict due to "
			  "access_mask = 0x%x\n",
			  (unsigned int)access_mask ));
		return False;
	}

#if 1 /* JRA TEST - Superdebug. */
#define CHECK_MASK(num, am, right, sa, share) \
	DEBUG(10,("share_conflict: [%d] am (0x%x) & right (0x%x) = 0x%x\n", \
		(unsigned int)(num), (unsigned int)(am), \
		(unsigned int)(right), (unsigned int)(am)&(right) )); \
	DEBUG(10,("share_conflict: [%d] sa (0x%x) & share (0x%x) = 0x%x\n", \
		(unsigned int)(num), (unsigned int)(sa), \
		(unsigned int)(share), (unsigned int)(sa)&(share) )); \
	if (((am) & (right)) && !((sa) & (share))) { \
		DEBUG(10,("share_conflict: check %d conflict am = 0x%x, right = 0x%x, \
sa = 0x%x, share = 0x%x\n", (num), (unsigned int)(am), (unsigned int)(right), (unsigned int)(sa), \
			(unsigned int)(share) )); \
		return True; \
	}
#else
#define CHECK_MASK(num, am, right, sa, share) \
	if (((am) & (right)) && !((sa) & (share))) { \
		DEBUG(10,("share_conflict: check %d conflict am = 0x%x, right = 0x%x, \
sa = 0x%x, share = 0x%x\n", (num), (unsigned int)(am), (unsigned int)(right), (unsigned int)(sa), \
			(unsigned int)(share) )); \
		return True; \
	}
#endif

	CHECK_MASK(1, entry->access_mask, FILE_WRITE_DATA | FILE_APPEND_DATA,
		   share_access, FILE_SHARE_WRITE);
	CHECK_MASK(2, access_mask, FILE_WRITE_DATA | FILE_APPEND_DATA,
		   entry->share_access, FILE_SHARE_WRITE);
	
	CHECK_MASK(3, entry->access_mask, FILE_READ_DATA | FILE_EXECUTE,
		   share_access, FILE_SHARE_READ);
	CHECK_MASK(4, access_mask, FILE_READ_DATA | FILE_EXECUTE,
		   entry->share_access, FILE_SHARE_READ);

	CHECK_MASK(5, entry->access_mask, DELETE_ACCESS,
		   share_access, FILE_SHARE_DELETE);
	CHECK_MASK(6, access_mask, DELETE_ACCESS,
		   entry->share_access, FILE_SHARE_DELETE);

	DEBUG(10,("share_conflict: No conflict.\n"));
	return False;
}

#if defined(DEVELOPER)
static void validate_my_share_entries(int num,
				      struct share_mode_entry *share_entry)
{
	files_struct *fsp;

	if (!procid_is_me(&share_entry->pid)) {
		return;
	}

	if (is_deferred_open_entry(share_entry) &&
	    !open_was_deferred(share_entry->op_mid)) {
		pstring str;
		DEBUG(0, ("Got a deferred entry without a request: "
			  "PANIC: %s\n", share_mode_str(num, share_entry)));
		smb_panic(str);
	}

	if (!is_valid_share_mode_entry(share_entry)) {
		return;
	}

	fsp = file_find_dif(share_entry->dev, share_entry->inode,
			    share_entry->share_file_id);
	if (!fsp) {
		DEBUG(0,("validate_my_share_entries: PANIC : %s\n",
			 share_mode_str(num, share_entry) ));
		smb_panic("validate_my_share_entries: Cannot match a "
			  "share entry with an open file\n");
	}

	if (is_deferred_open_entry(share_entry) ||
	    is_unused_share_mode_entry(share_entry)) {
		goto panic;
	}

	if ((share_entry->op_type == NO_OPLOCK) &&
	    (fsp->oplock_type == FAKE_LEVEL_II_OPLOCK)) {
		/* Someone has already written to it, but I haven't yet
		 * noticed */
		return;
	}

	if (((uint16)fsp->oplock_type) != share_entry->op_type) {
		goto panic;
	}

	return;

 panic:
	{
		pstring str;