msdfs.c

samba-3.0.22.tar.gz 编译smb服务器的源码

/* 
   Unix SMB/Netbios implementation.
   Version 3.0
   MSDfs services for Samba
   Copyright (C) Shirish Kalele 2000

   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.

*/

#define DBGC_CLASS DBGC_MSDFS
#include "includes.h"

extern uint32 global_client_caps;

/**********************************************************************
  Parse the pathname  of the form \hostname\service\reqpath
  into the dfs_path structure 
 **********************************************************************/

static BOOL parse_dfs_path(char *pathname, struct dfs_path *pdp)
{
	pstring pathname_local;
	char *p, *temp;

	pstrcpy(pathname_local,pathname);
	p = temp = pathname_local;

	ZERO_STRUCTP(pdp);

	trim_char(temp,'\\','\\');
	DEBUG(10,("temp in parse_dfs_path: .%s. after trimming \\'s\n",temp));

	/* now tokenize */
	/* parse out hostname */
	p = strchr_m(temp,'\\');
	if(p == NULL) {
		return False;
	}
	*p = '\0';
	pstrcpy(pdp->hostname,temp);
	DEBUG(10,("parse_dfs_path: hostname: %s\n",pdp->hostname));

	/* parse out servicename */
	temp = p+1;
	p = strchr_m(temp,'\\');
	if(p == NULL) {
		pstrcpy(pdp->servicename,temp);
		pdp->reqpath[0] = '\0';
		return True;
	}
	*p = '\0';
	pstrcpy(pdp->servicename,temp);
	DEBUG(10,("parse_dfs_path: servicename: %s\n",pdp->servicename));

	/* rest is reqpath */
	check_path_syntax(pdp->reqpath, p+1);

	DEBUG(10,("parse_dfs_path: rest of the path: %s\n",pdp->reqpath));
	return True;
}

/**********************************************************************
  Parse the pathname  of the form /hostname/service/reqpath
  into the dfs_path structure 
 **********************************************************************/

static BOOL parse_processed_dfs_path(char* pathname, struct dfs_path *pdp, BOOL allow_wcards)
{
	pstring pathname_local;
	char *p,*temp;

	pstrcpy(pathname_local,pathname);
	p = temp = pathname_local;

	ZERO_STRUCTP(pdp);

	trim_char(temp,'/','/');
	DEBUG(10,("temp in parse_processed_dfs_path: .%s. after trimming \\'s\n",temp));

	/* now tokenize */
	/* parse out hostname */
	p = strchr_m(temp,'/');
	if(p == NULL) {
		return False;
	}
	*p = '\0';
	pstrcpy(pdp->hostname,temp);
	DEBUG(10,("parse_processed_dfs_path: hostname: %s\n",pdp->hostname));

	/* parse out servicename */
	temp = p+1;
	p = strchr_m(temp,'/');
	if(p == NULL) {
		pstrcpy(pdp->servicename,temp);
		pdp->reqpath[0] = '\0';
		return True;
	}
	*p = '\0';
	pstrcpy(pdp->servicename,temp);
	DEBUG(10,("parse_processed_dfs_path: servicename: %s\n",pdp->servicename));

	/* rest is reqpath */
	if (allow_wcards) {
		BOOL path_contains_wcard;
		check_path_syntax_wcard(pdp->reqpath, p+1, &path_contains_wcard);
	} else {
		check_path_syntax(pdp->reqpath, p+1);
	}

	DEBUG(10,("parse_processed_dfs_path: rest of the path: %s\n",pdp->reqpath));
	return True;
}

/********************************************************
 Fake up a connection struct for the VFS layer.
 Note this CHANGES CWD !!!! JRA.
*********************************************************/

static BOOL create_conn_struct(connection_struct *conn, int snum, char *path)
{
	pstring connpath;

	ZERO_STRUCTP(conn);

	conn->service = snum;
	pstrcpy(connpath, path);
	pstring_sub(connpath , "%S", lp_servicename(snum));

	/* needed for smbd_vfs_init() */
	
        if ( (conn->mem_ctx=talloc_init("connection_struct")) == NULL ) {
                DEBUG(0,("talloc_init(connection_struct) failed!\n"));
                return False;
        }
	
	string_set(&conn->connectpath, connpath);

	if (!smbd_vfs_init(conn)) {
		DEBUG(0,("create_conn_struct: smbd_vfs_init failed.\n"));
		conn_free_internal(conn);
		return False;
	}

	/*
	 * Windows seems to insist on doing trans2getdfsreferral() calls on the IPC$
	 * share as the anonymous user. If we try to chdir as that user we will
	 * fail.... WTF ? JRA.
	 */

	if (vfs_ChDir(conn,conn->connectpath) != 0) {
		DEBUG(3,("create_conn_struct: Can't ChDir to new conn path %s. Error was %s\n",
					conn->connectpath, strerror(errno) ));
		conn_free_internal(conn);
		return False;
	}

	return True;
}

/**********************************************************************
 Parse the contents of a symlink to verify if it is an msdfs referral
 A valid referral is of the form: msdfs:server1\share1,server2\share2
 talloc CTX can be NULL here if preflist and refcount pointers are null.
 **********************************************************************/

static BOOL parse_symlink(TALLOC_CTX *ctx, char *buf, struct referral **preflist, int *refcount)
{
	pstring temp;
	char *prot;
	char *alt_path[MAX_REFERRAL_COUNT];
	int count = 0, i;
	struct referral *reflist;

	pstrcpy(temp,buf);
  
	prot = strtok(temp,":");

	if (!strequal(prot, "msdfs")) {
		return False;
	}

	/* No referral list requested. Just yes/no. */
	if (!preflist) {
		return True;
	}

	if (!ctx) {
		DEBUG(0,("parse_symlink: logic error. TALLOC_CTX should not be null.\n"));
		return True;
	}

	/* parse out the alternate paths */
	while(((alt_path[count] = strtok(NULL,",")) != NULL) && count<MAX_REFERRAL_COUNT) {
		count++;
	}

	DEBUG(10,("parse_symlink: count=%d\n", count));

	reflist = *preflist = TALLOC_ARRAY(ctx, struct referral, count);
	if(reflist == NULL) {
		DEBUG(0,("parse_symlink: talloc failed!\n"));
		return False;
	}
	
	for(i=0;i<count;i++) {
		char *p;

		/* replace all /'s in the alternate path by a \ */
		for(p = alt_path[i]; *p && ((p = strchr_m(p,'/'))!=NULL); p++) {
			*p = '\\'; 
		}

		/* Remove leading '\\'s */
		p = alt_path[i];
		while (*p && (*p == '\\')) {
			p++;
		}

		pstrcpy(reflist[i].alternate_path, "\\");
		pstrcat(reflist[i].alternate_path, p);
		reflist[i].proximity = 0;
		reflist[i].ttl = REFERRAL_TTL;
		DEBUG(10, ("parse_symlink: Created alt path: %s\n", reflist[i].alternate_path));
	}

	if(refcount) {
		*refcount = count;
	}

	return True;
}
 
/**********************************************************************
 Returns true if the unix path is a valid msdfs symlink
 talloc CTX can be NULL here if reflistp and refcnt pointers are null.
 **********************************************************************/

BOOL is_msdfs_link(TALLOC_CTX *ctx, connection_struct *conn, char *path,
		   struct referral **reflistp, int *refcnt,
		   SMB_STRUCT_STAT *sbufp)
{
	SMB_STRUCT_STAT st;
	pstring referral;
	int referral_len = 0;

	if (!path || !conn) {
		return False;
	}

	if (sbufp == NULL) {
		sbufp = &st;
	}

	if (SMB_VFS_LSTAT(conn, path, sbufp) != 0) {
		DEBUG(5,("is_msdfs_link: %s does not exist.\n",path));
		return False;
	}
  
	if (S_ISLNK(sbufp->st_mode)) {
		/* open the link and read it */
		referral_len = SMB_VFS_READLINK(conn, path, referral, sizeof(pstring)-1);
		if (referral_len == -1) {
			DEBUG(0,("is_msdfs_link: Error reading msdfs link %s: %s\n", path, strerror(errno)));
			return False;
		}

		referral[referral_len] = '\0';
		DEBUG(5,("is_msdfs_link: %s -> %s\n",path,referral));
		if (parse_symlink(ctx, referral, reflistp, refcnt)) {
			return True;
		}
	}
	return False;
}

/*****************************************************************
 Used by other functions to decide if a dfs path is remote,
and to get the list of referred locations for that remote path.
 
findfirst_flag: For findfirsts, dfs links themselves are not
redirected, but paths beyond the links are. For normal smb calls,
even dfs links need to be redirected.

self_referralp: clients expect a dfs referral for the same share when
they request referrals for dfs roots on a server. 

consumedcntp: how much of the dfs path is being redirected. the client
should try the remaining path on the redirected server.

TALLOC_CTX can be NULL here if struct referral **reflistpp, int *refcntp
are also NULL.
*****************************************************************/

static BOOL resolve_dfs_path(TALLOC_CTX *ctx, pstring dfspath, struct dfs_path *dp, 
		      connection_struct *conn, BOOL search_flag, 
		      struct referral **reflistpp, int *refcntp,
		      BOOL *self_referralp, int *consumedcntp)
{
	pstring localpath;
	int consumed_level = 1;
	char *p;
	BOOL bad_path = False;
	SMB_STRUCT_STAT sbuf;
	pstring reqpath;

	if (!dp || !conn) {
		DEBUG(1,("resolve_dfs_path: NULL dfs_path* or NULL connection_struct*!\n"));
		return False;
	}

	if (!ctx && (reflistpp || refcntp)) {
		DEBUG(0,("resolve_dfs_path: logic error. TALLOC_CTX must not be NULL.\n"));
	}

	if (dp->reqpath[0] == '\0') {
		if (self_referralp) {
			DEBUG(6,("resolve_dfs_path: self-referral. returning False\n"));
			*self_referralp = True;
		}
		return False;
	}

	DEBUG(10,("resolve_dfs_path: Conn path = %s req_path = %s\n", conn->connectpath, dp->reqpath));

	unix_convert(dp->reqpath,conn,0,&bad_path,&sbuf);
	/* JRA... should we strlower the last component here.... ? */
	pstrcpy(localpath, dp->reqpath);

	/* check if need to redirect */
	if (is_msdfs_link(ctx, conn, localpath, reflistpp, refcntp, NULL)) {
		if ( search_flag ) {
			DEBUG(6,("resolve_dfs_path (FindFirst) No redirection "
				 "for dfs link %s.\n", dfspath));
			return False;
		}

		DEBUG(6,("resolve_dfs_path: %s resolves to a valid Dfs link.\n", dfspath));
		if (consumedcntp) {
			*consumedcntp = strlen(dfspath);
		}
		return True;
	}

	/* redirect if any component in the path is a link */
	pstrcpy(reqpath, dp->reqpath);
	p = strrchr_m(reqpath, '/');
	while (p) {
		*p = '\0';
		pstrcpy(localpath, reqpath);
		if (is_msdfs_link(ctx, conn, localpath, reflistpp, refcntp, NULL)) {
			DEBUG(4, ("resolve_dfs_path: Redirecting %s because parent %s is dfs link\n", dfspath, localpath));

			/* To find the path consumed, we truncate the original
			   DFS pathname passed to use to remove the last
			   component. The length of the resulting string is
			   the path consumed 
			*/
			
			if (consumedcntp) {
				char *q;
				pstring buf;
				pstrcpy(buf, dfspath);
				trim_char(buf, '\0', '\\');
				for (; consumed_level; consumed_level--) {
					q = strrchr_m(buf, '\\');
					if (q) {
						*q = 0;
					}
				}
				*consumedcntp = strlen(buf);
				DEBUG(10, ("resolve_dfs_path: Path consumed: %s (%d)\n", buf, *consumedcntp));
			}
			
			return True;
		}
		p = strrchr_m(reqpath, '/');
		consumed_level++;
	}

	return False;
}

/*****************************************************************
  Decides if a dfs pathname should be redirected or not.
  If not, the pathname is converted to a tcon-relative local unix path

  search_wcard_flag: this flag performs 2 functions bother related
  to searches.  See resolve_dfs_path() and parse_processed_dfs_path()
  for details.
*****************************************************************/

BOOL dfs_redirect( pstring pathname, connection_struct *conn, BOOL search_wcard_flag )
{
	struct dfs_path dp;
	
	if (!conn || !pathname) {
		return False;
	}

	parse_processed_dfs_path(pathname, &dp, search_wcard_flag);

	/* if dfs pathname for a non-dfs share, convert to tcon-relative
	   path and return false */
	if (!lp_msdfs_root(SNUM(conn))) {
		pstrcpy(pathname, dp.reqpath);
		return False;
	}
	
	if (!strequal(dp.servicename, lp_servicename(SNUM(conn)) )) {
		return False;
	}

	if (resolve_dfs_path(NULL, pathname, &dp, conn, search_wcard_flag,
			     NULL, NULL, NULL, NULL)) {
		DEBUG(3,("dfs_redirect: Redirecting %s\n", pathname));
		return True;
	} else {
		DEBUG(3,("dfs_redirect: Not redirecting %s.\n", pathname));
		
		/* Form non-dfs tcon-relative path */
		pstrcpy(pathname, dp.reqpath);
		DEBUG(3,("dfs_redirect: Path converted to non-dfs path %s\n", pathname));
		return False;
	}

	/* never reached */
}

/**********************************************************************
 Return a self referral.
**********************************************************************/

static BOOL self_ref(TALLOC_CTX *ctx, char *pathname, struct junction_map *jucn,
			int *consumedcntp, BOOL *self_referralp)
{
	struct referral *ref;

	if (self_referralp != NULL) {
		*self_referralp = True;
	}

	jucn->referral_count = 1;
	if((ref = TALLOC_P(ctx, struct referral)) == NULL) {
		DEBUG(0,("self_ref: malloc failed for referral\n"));
		return False;
	}

	pstrcpy(ref->alternate_path,pathname);
	ref->proximity = 0;
	ref->ttl = REFERRAL_TTL;
	jucn->referral_list = ref;
	if (consumedcntp) {
		*consumedcntp = strlen(pathname);
	}

	return True;
}

/**********************************************************************
 Gets valid referrals for a dfs path and fills up the
 junction_map structure.
**********************************************************************/

BOOL get_referred_path(TALLOC_CTX *ctx, char *pathname, struct junction_map *jucn,
		       int *consumedcntp, BOOL *self_referralp)
{
	struct dfs_path dp;

	struct connection_struct conns;
	struct connection_struct *conn = &conns;
	pstring conn_path;
	int snum;
	BOOL ret = False;
	BOOL self_referral = False;

	if (!pathname || !jucn) {
		return False;
	}

	ZERO_STRUCT(conns);

	if (self_referralp) {
		*self_referralp = False;
	} else {
		self_referralp = &self_referral;
	}

	parse_dfs_path(pathname, &dp);

	/* Verify hostname in path */
	if ( !strequal(get_local_machine_name(), dp.hostname) ) {
		/* Hostname mismatch, check if one of our IP addresses */
		if (!ismyip(*interpret_addr2(dp.hostname))) {
			DEBUG(3, ("get_referred_path: Invalid hostname %s in path %s\n",
				dp.hostname, pathname));
			return False;
		}
	}

	pstrcpy(jucn->service_name, dp.servicename);
	pstrcpy(jucn->volume_name, dp.reqpath);

	/* Verify the share is a dfs root */
	snum = lp_servicenumber(jucn->service_name);
	if(snum < 0) {
		if ((snum = find_service(jucn->service_name)) < 0) {
			return False;
		}
	}

	if (!lp_msdfs_root(snum)) {
		DEBUG(3,("get_referred_path: .%s. in dfs path %s is not a dfs root.\n",
			 dp.servicename, pathname));
		goto out;
	}

	/*
	 * Self referrals are tested with a anonymous IPC connection and
	 * a GET_DFS_REFERRAL call to \\server\share. (which means dp.reqpath[0] points
	 * to an empty string). create_conn_struct cd's into the directory and will
	 * fail if it cannot (as the anonymous user). Cope with this.
	 */

	if (dp.reqpath[0] == '\0') {

		struct referral* ref;

		if (*lp_msdfs_proxy(snum) == '\0') {
			return self_ref(ctx, pathname, jucn, consumedcntp, self_referralp);
		}

		jucn->referral_count = 1;
		if ((ref = TALLOC_P(ctx, struct referral)) == NULL) {
			DEBUG(0, ("malloc failed for referral\n"));
			goto out;
		}

		pstrcpy(ref->alternate_path, lp_msdfs_proxy(snum));
		if (dp.reqpath[0] != '\0') {
			pstrcat(ref->alternate_path, dp.reqpath);
		}
		ref->proximity = 0;