path: root/source3/lib/substitute.c

/* 
   Unix SMB/CIFS implementation.
   string substitution functions
   Copyright (C) Andrew Tridgell 1992-2000
   
   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.
*/


#include "includes.h"

fstring local_machine="";
fstring remote_arch="UNKNOWN";
userdom_struct current_user_info;
fstring remote_proto="UNKNOWN";
fstring remote_machine="";
extern pstring global_myname;

/*******************************************************************
 Given a pointer to a %$(NAME) expand it as an environment variable.
 Return the number of characters by which the pointer should be advanced.
 Based on code by Branko Cibej <branko.cibej@hermes.si>
 When this is called p points at the '%' character.
********************************************************************/

static size_t expand_env_var(char *p, int len)
{
	fstring envname;
	char *envval;
	char *q, *r;
	int copylen;

	if (p[1] != '$')
		return 1;

	if (p[2] != '(')
		return 2;

	/*
	 * Look for the terminating ')'.
	 */

	if ((q = strchr_m(p,')')) == NULL) {
		DEBUG(0,("expand_env_var: Unterminated environment variable [%s]\n", p));
		return 2;
	}

	/*
	 * Extract the name from within the %$(NAME) string.
	 */

	r = p+3;
	copylen = MIN((q-r),(sizeof(envname)-1));
	strncpy(envname,r,copylen);
	envname[copylen] = '\0';

	if ((envval = getenv(envname)) == NULL) {
		DEBUG(0,("expand_env_var: Environment variable [%s] not set\n", envname));
		return 2;
	}

	/*
	 * Copy the full %$(NAME) into envname so it
	 * can be replaced.
	 */

	copylen = MIN((q+1-p),(sizeof(envname)-1));
	strncpy(envname,p,copylen);
	envname[copylen] = '\0';
	string_sub(p,envname,envval,len);
	return 0; /* Allow the environment contents to be parsed. */
}

/*******************************************************************
 Patch from jkf@soton.ac.uk
 Added this to implement %p (NIS auto-map version of %H)
*******************************************************************/

static char *automount_path(const char *user_name)
{
	static pstring server_path;

	/* use the passwd entry as the default */
	/* this will be the default if WITH_AUTOMOUNT is not used or fails */

	pstrcpy(server_path, get_user_home_dir(user_name));

#if (defined(HAVE_NETGROUP) && defined (WITH_AUTOMOUNT))

	if (lp_nis_home_map()) {
		char *home_path_start;
		char *automount_value = automount_lookup(user_name);

		if(strlen(automount_value) > 0) {
			home_path_start = strchr_m(automount_value,':');
			if (home_path_start != NULL) {
				DEBUG(5, ("NIS lookup succeeded.  Home path is: %s\n",
						home_path_start?(home_path_start+1):""));
				pstrcpy(server_path, home_path_start+1);
			}
		} else {
			/* NIS key lookup failed: default to user home directory from password file */
			DEBUG(5, ("NIS lookup failed. Using Home path from passwd file. Home path is: %s\n", server_path ));
		}
	}
#endif

	DEBUG(4,("Home server path: %s\n", server_path));

	return server_path;
}

/*******************************************************************
 Patch from jkf@soton.ac.uk
 This is Luke's original function with the NIS lookup code
 moved out to a separate function.
*******************************************************************/

static char *automount_server(const char *user_name)
{
	static pstring server_name;

	/* use the local machine name as the default */
	/* this will be the default if WITH_AUTOMOUNT is not used or fails */
	if (*local_machine)
		pstrcpy(server_name, local_machine);
	else
		pstrcpy(server_name, global_myname);
	
#if (defined(HAVE_NETGROUP) && defined (WITH_AUTOMOUNT))

	if (lp_nis_home_map()) {
	        int home_server_len;
		char *automount_value = automount_lookup(user_name);
		home_server_len = strcspn(automount_value,":");
		DEBUG(5, ("NIS lookup succeeded.  Home server length: %d\n",home_server_len));
		if (home_server_len > sizeof(pstring))
			home_server_len = sizeof(pstring);
		strncpy(server_name, automount_value, home_server_len);
                server_name[home_server_len] = '\0';
	}
#endif

	DEBUG(4,("Home server: %s\n", server_name));

	return server_name;
}

/****************************************************************************
 Do some standard substitutions in a string.
 len is the length in bytes of the space allowed in string str. If zero means
 don't allow expansions.
****************************************************************************/

void standard_sub_basic(const char *smb_name, char *str,size_t len)
{
	char *p, *s;
	fstring pidstr;
	struct passwd *pass;

	for (s=str; (p=strchr_m(s, '%'));s=p) {
		fstring tmp_str;

		int l = (int)len - (int)(p-str);

		if (l < 0)
			l = 0;
		
		switch (*(p+1)) {
		case 'U' : 
			fstrcpy(tmp_str, smb_name);
			strlower(tmp_str);
			string_sub(p,"%U",tmp_str,l);
			break;
		case 'G' :
			fstrcpy(tmp_str, smb_name);
			if ((pass = Get_Pwnam(tmp_str))!=NULL) {
				string_sub(p,"%G",gidtoname(pass->pw_gid),l);
			} else {
				p += 2;
			}
			break;
		case 'D' :
			fstrcpy(tmp_str, current_user_info.domain);
			strupper(tmp_str);
			string_sub(p,"%D", tmp_str,l);
			break;
		case 'I' :
			string_sub(p,"%I", client_addr(),l);
			break;
		case 'L' : 
			if (*local_machine)
				string_sub(p,"%L", local_machine,l); 
			else
				string_sub(p,"%L", global_myname,l); 
			break;
		case 'M' :
			string_sub(p,"%M", client_name(),l);
			break;
		case 'R' :
			string_sub(p,"%R", remote_proto,l);
			break;
		case 'T' :
			string_sub(p,"%T", timestring(False),l);
			break;
		case 'a' :
			string_sub(p,"%a", remote_arch,l);
			break;
		case 'd' :
			slprintf(pidstr,sizeof(pidstr)-1, "%d",(int)sys_getpid());
			string_sub(p,"%d", pidstr,l);
			break;
		case 'h' :
			string_sub(p,"%h", myhostname(),l);
			break;
		case 'm' :
			string_sub(p,"%m", remote_machine,l);
			break;
		case 'v' :
			string_sub(p,"%v", VERSION,l);
			break;
		case '$' :
			p += expand_env_var(p,l);
			break; /* Expand environment variables */
		case '\0': 
			p++; 
			break; /* don't run off the end of the string */
			
		default: p+=2; 
			break;
		}
	}
}

/****************************************************************************
 Do some standard substitutions in a string.
****************************************************************************/

static void standard_sub_advanced(int snum, const char *user, 
				  const char *connectpath, gid_t gid, 
				  const char *smb_name, char *str, size_t len)
{
	char *p, *s, *home;

	for (s=str; (p=strchr_m(s, '%'));s=p) {
		int l = (int)len - (int)(p-str);
	
		if (l < 0)
			l = 0;
	
		switch (*(p+1)) {
		case 'N' :
			string_sub(p,"%N", automount_server(user),l);
			break;
		case 'H':
			if ((home = get_user_home_dir(user)))
				string_sub(p,"%H",home, l);
			else
				p += 2;
			break;
		case 'P': 
			string_sub(p,"%P", connectpath, l); 
			break;
		case 'S': 
			string_sub(p,"%S", lp_servicename(snum), l); 
			break;
		case 'g': 
			string_sub(p,"%g", gidtoname(gid), l); 
			break;
		case 'u': 
			string_sub(p,"%u", user, l); 
			break;
			
			/* Patch from jkf@soton.ac.uk Left the %N (NIS
			 * server name) in standard_sub_basic as it is
			 * a feature for logon servers, hence uses the
			 * username.  The %p (NIS server path) code is
			 * here as it is used instead of the default
			 * "path =" string in [homes] and so needs the
			 * service name, not the username.  */
		case 'p': 
			string_sub(p,"%p", automount_path(lp_servicename(snum)), l); 
			break;
		case '\0': 
			p++; 
			break; /* don't run off the end of the string */
			
		default: p+=2; 
			break;
		}
	}

	standard_sub_basic(smb_name, str, len);
}

const char *standard_sub_specified(TALLOC_CTX *mem_ctx, const char *input_string,
				   const char *username,
				   const char *domain,
				   uid_t uid,
				   gid_t gid) 
{
	pstring input_pstring;
	char *p, *s;

	pstrcpy(input_pstring, input_string);
	
	for (s=input_pstring; (p=strchr_m(s, '%')); s=p) {

		int l = sizeof(pstring) - (int)(p-input_pstring);
		
		switch (*(p+1)) {
		case 'U' : 
			string_sub(p,"%U",username,l);
			break;
		case 'u' : 
			string_sub(p,"%u",username,l);
			break;
		case 'G' :
		case 'g' :
			if (gid != -1) {
				string_sub(p,"%G",gidtoname(gid),l);
				string_sub(p,"%g",gidtoname(gid),l);
			} else {
				string_sub(p,"%G","NO_GROUP",l);
				string_sub(p,"%g","NO_GROUP",l);
			}
			break;
		case 'D' :
			string_sub(p,"%D", domain,l);
			break;
		case 'N' : 
			string_sub(p,"%N", automount_server(username),l); 
			break;
		case '\0': 
			p++; 
			break; /* don't run off the end of the string */
			
		default: p+=2; 
			break;
		}
	}

	standard_sub_basic(username, input_pstring, sizeof(pstring));
	return talloc_strdup(mem_ctx, input_pstring);
}

/****************************************************************************
 Do some standard substitutions in a string.
****************************************************************************/

void standard_sub_conn(connection_struct *conn, char *str, size_t len)
{
	standard_sub_advanced(SNUM(conn), conn->user, conn->connectpath,
			conn->gid, current_user_info.smb_name, str, len);
}

/****************************************************************************
 Like standard_sub but by snum.
****************************************************************************/

void standard_sub_snum(int snum, char *str, size_t len)
{
	extern struct current_user current_user;
	static uid_t cached_uid = -1;
	static fstring cached_user;
	/* calling uidtoname() on every substitute would be too expensive, so
	   we cache the result here as nearly every call is for the same uid */

	if (cached_uid != current_user.uid) {
		fstrcpy(cached_user, uidtoname(current_user.uid));
		cached_uid = current_user.uid;
	}

	standard_sub_advanced(snum, cached_user, "", -1,
		current_user_info.smb_name, str, len);
}