yp_bind.c

操作系统SunOS 4.1.3版本的源码

#if	!defined(lint) && defined(SCCSIDS)
static  char sccsid[] = "@(#)yp_bind.c 1.1 92/07/30 Copyr 1990 Sun Micro";
#endif
#ifdef	sun
#define	MAP_STUFF 1
#endif

#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/time.h>
#include <rpc/rpc.h>
#include <rpc/pmap_prot.h>
#include <sys/socket.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/syslog.h>

#include "yp_prot.h"
#include "ypv1_prot.h"
#include "ypclnt.h"

#define	BFSIZE (YPMAXDOMAIN + 32) /* size of binding file */

/* This should match the one in ypbind.c */

#define	CACHE_DIR "/var/yp/binding"
extern int errno;
extern int sleep();
extern malloc_t malloc();
extern char *strcpy();
static void _yp_unbind();

enum	bind_status {
	BS_BAGIT,
	BS_RETRY,
	BS_OK
};

bool check_pmap_up();
bool check_binder_up();
enum	bind_status talk2_pmap();
enum	bind_status talk2_binder();
void talk2_server();
enum	bind_status get_binder_port();
bool check_binding();
void newborn();
struct	dom_binding *load_dom_binding();

/*
 * Time parameters when talking to the ypbind and pmap processes
 */

#define	YPSLEEPTIME 5			/* Time to sleep between tries */
unsigned int _ypsleeptime = YPSLEEPTIME;

#define	YPBIND_TIMEOUT 30		/* Total seconds for timeout */
#define	YPBIND_INTER_TRY 30		/* Seconds between tries */

static struct timeval bind_intertry = {
	YPBIND_INTER_TRY,		/* Seconds */
	0				/* Microseconds */
	};
static struct timeval bind_timeout = {
	YPBIND_TIMEOUT,			/* Seconds */
	0				/* Microseconds */
	};

/*
 * Time parameters when talking to the ypserv process
 */

#ifdef	 DEBUG
#define	YPTIMEOUT 120			/* Total seconds for timeout */
#define	YPINTER_TRY 60			/* Seconds between tries */
#else
#define	YPTIMEOUT 90			/* Total seconds for timeout */
#define	YPINTER_TRY 5			/* Seconds between tries */
#endif

#define	MAX_TRIES_FOR_NEW_YP 1		/* Number of times we'll try to get
					 *   a new YP server before we'll
					 *   settle for an old one. */
static struct timeval ypserv_intertry = {
	YPINTER_TRY,			/* Seconds */
	0				/* Microseconds */
	};
struct	timeval _ypserv_timeout = {
	YPTIMEOUT,			/* Seconds */
	0				/* Microseconds */
	};

static struct in_addr my_addr;		/* Local internet addr */
static struct dom_binding *bound_domains; /* List of bound domains */
static char *default_domain;
static char	bfinvalid;		/* Binding file invalid	*/
static char     *bfname;
#ifdef	MAP_STUFF
#include <sys/mman.h>
static u_short	*binderfilemap;		/* Mapped version of binder */
#define	MAP_LEN (2+sizeof(struct ypbind_resp))			/* just for current udp only*/
#endif
static int	bf;			/* Binding file fd	*/
/*
 * binder_port holds what we believe to be the local port for ypbind.  It is
 * set only by talk2_pmap.  It is cleared (set to 0) by:
 *	1. talk2_pmap: always upon entry.
 *	2. check_binder_up if:
 *		- It can't create a socket to speak to the binder.
 *		- If it fails to bind to the port.
 *	3. talk2_binder if there are RPC errors when trying to use the port.
 */
static unsigned long binder_port;	/* Initialize to "no port" */

/*
 * Attempts to locate a NIS server that serves a passed domain.  If
 * one is found, an entry is created on the static list of domain-server pairs
 * pointed to by cell bound_domains, a udp path to the server is created and
 * the function returns 0.  Otherwise, the function returns a defined errorcode
 * YPERR_xxxx.
 */
int
_yp_dobind(domain, binding)
	char *domain;
	struct dom_binding **binding;	/* if result == 0, ptr to dom_binding */
{
return (_yp_dobind_soft(domain,binding, -1));
}
int
_yp_dobind_soft(domain, binding,usertries)
	char *domain;
	struct dom_binding **binding;	/* if result == 0, ptr to dom_binding */
	int usertries;
{
	struct dom_binding *pdomb;	/* Ptr to new domain binding */
	struct sockaddr_in ypbinder;	/* To talk with ypbinder */
	char *pdomain;			/* For xdr interface */
	struct ypbind_resp ypbind_resp; /* Response from local ypbinder */
	int vers;			/* ypbind program version number */
	int tries;			/* Number of times we've tried with
					 *  the current protocol */
	int gbtries;			/* Number of times we've tried to
					 *  get the binder */
	int status;
	u_short		b_port;
	enum bind_status loopctl;
	bool bound;
	bool oldport = FALSE;
#ifdef	MAP_STUFF
	char tmpbfname[BFSIZE];
#endif

	if ( (domain == NULL) ||(strlen(domain) == 0) ) {
		return (YPERR_BADARGS);
	}

	newborn();
	if (bfname==0){
	bfname=(char *)calloc(1,BFSIZE);
	}
	if (bfname==0){
	bfinvalid=TRUE;
	}

	if (!bfinvalid) {

#ifdef	MAP_STUFF
		sprintf(tmpbfname,"%s/%s.%d",CACHE_DIR,domain,YPVERS);
		if (strcmp(bfname,tmpbfname)==0){ /*same name*/
			if (binderfilemap){
			binder_port =  binderfilemap[0];
			}
		} else {
			bfname[0]=0;
			if (binderfilemap){
			munmap(binderfilemap,MAP_LEN);
			binderfilemap=0;
			}
			if ((bf = open(tmpbfname,O_RDONLY)) != -1) {
			if (flock(bf,LOCK_EX+LOCK_NB) == 0) {
				close(bf);
				bf = -1; /* Not valid if we would lock it */
			} else {
			binderfilemap=(u_short *)mmap(bfname,MAP_LEN,PROT_READ,MAP_SHARED,bf,0);
			if ((int)binderfilemap == -1) binderfilemap=0;
			if (binderfilemap){
				strcpy(bfname,tmpbfname);
				binder_port =  binderfilemap[0];
				close(bf);
				}
			else   {
				close(bf);
				bf= -1; /*map failed*/
				}
			   }
			}
		}
#else
		sprintf(bfname,"%s/%s.%d",CACHE_DIR,domain,YPVERS);
		if ((bf = open(bfname,O_RDONLY)) != -1) {
			if (flock(bf,LOCK_EX+LOCK_NB) == 0) {
				close(bf);
				bf = -1; /* Not valid if we would lock it */
			} else {
				read(bf,&b_port,sizeof(u_short));
				binder_port = b_port;
				close(bf);
			}
		}
#endif
	}

	if (check_binding(domain, binding) )
		return (0);		/* We are bound */

	/*
	 * Use loopback address.
	 */
	my_addr.s_addr = INADDR_LOOPBACK;

	pdomain = domain;

	/*
	 * Try to get the binder's port, using the current program version.
	 * The version may be changed to the old version, deep in the bowels
	 * of talk2_binder.
	 */
	for (bound = FALSE, vers = YPBINDVERS; !bound; ) {

		if (binder_port) {
			oldport = TRUE;
		} else {
			oldport = FALSE;

			/*
			 * Get the binder's port.  We'll loop as long as
			 * get_binder_port returns BS_RETRY.
			 */
			for (gbtries=0,loopctl = BS_RETRY; loopctl != BS_OK;gbtries++ ) {

				if ((usertries>=0) && gbtries >=usertries) return (status);
	 			switch (loopctl =
				    get_binder_port(vers, &status) ) {
				case BS_BAGIT:
					return (status);
				case BS_OK:
					break;
				}
			}
		}

		/*
		 * See whether ypbind is up.  If no, bag it if it's a
		 * resource error, or if we are using a port we just got
		 * from the port mapper.  Otherwise loop around to try to
		 * get a valid port.
		 */
		if (!check_binder_up(&ypbinder, &status)) {

			if (status == YPERR_RESRC) {
				return (status);
			}

			if (!oldport && status == YPERR_YPBIND) {
				return (status);
			}

			continue;
		}

		/*
		 * At this point, we think we know how to talk to the
		 * binder, and the binder is apparently alive.  Until we
		 * succeed in binding the domain, or we know we can't ever
		 * bind the domain, we will try forever.  This loops when
		 * talk2_binder returns BS_RETRY, and terminates when
		 * talk2_binder returns BS_BAGIT, or BS_OK.  If binder_port
		 * gets cleared, we will not execute this loop again, but
		 * will go to the top of the enclosing loop to try to get
		 * the binder's port again.  It is never the case that both
		 * talk2_binder returns  BS_OK and that it clears the
		 * binder_port.
		 */
		for (loopctl = BS_RETRY, tries = 1;
		    binder_port && (loopctl != BS_OK); tries++) {

			switch (loopctl = talk2_binder(&ypbinder, &vers,
			    tries, &pdomain, &ypbind_resp, &status) ) {
			case BS_BAGIT:
				return (status);
			case BS_OK:
				bound = TRUE;
			}
			if ((usertries>=0) && tries >=usertries) return (status);
		}
	}

	if ( (pdomb = load_dom_binding(&ypbind_resp, vers, domain, &status) ) ==
	    (struct dom_binding *) NULL) {
		return (status);
	}

	if (vers == YPBINDOLDVERS) {
		talk2_server(pdomb);
	}

	*binding = pdomb;			/* Return ptr to the binding
						 *   entry */
	return (0);				/* This is the go path */
}

/*
 * This is a "wrapper" function for _yp_dobind_soft for vanilla user-level
 * functions which neither know nor care about struct dom_bindings.
 */
int
yp_bind(domain)
	char *domain;
{

	struct dom_binding *binding;

	return (_yp_dobind(domain, &binding) );
}


/*
 * This is a "wrapper" function for _yp_dobind_soft for vanilla user-level
 * functions which neither know nor care about struct dom_bindings.
 */
int
yp_softbind(domain,tries)
	char *domain;
	int tries;
{

	struct dom_binding *binding;

	return (_yp_dobind_soft(domain, &binding, tries) );
}

/*
 * Attempts to find a dom_binding in the list at bound_domains having the
 * domain name field equal to the passed domain name, and removes it if found.
 * The domain-server binding will not exist after the call to this function.
 * All resources associated with the binding will be freed.
 */
void
yp_unbind (domain)
	char *domain;
{
_yp_unbind(domain, TRUE);
}

static void
_yp_unbind (domain, invalidate)
	char *domain;
	bool_t invalidate; /*the binding file*/
{
	struct dom_binding *pdomb;
	struct dom_binding *ptrail = 0;
	struct sockaddr_in local_name;
	int local_name_len;


	if ( (domain == NULL) ||(strlen(domain) == 0) ) {
		return;
	}
	if (invalidate) bfinvalid = TRUE; /* Don't use binding file again */

	for (pdomb = bound_domains; pdomb != NULL;
	    ptrail = pdomb, pdomb = pdomb->dom_pnext) {

		if (strcmp(domain, pdomb->dom_domain) == 0) {
			/*
			 * The act of destroying the rpc client closes
			 * the associated socket.  However, the fd
			 * representing what we believe to be our socket may
			 * really belong to someone else due to closes
			 * followed by new opens.   So let us be very careful!
			 */
			local_name_len = sizeof (local_name);
			if ((getsockname(pdomb->dom_socket,
			    (struct sockaddr *) &local_name,
			    &local_name_len) != 0)  ||
			    (local_name.sin_family != AF_INET) ||
			    (local_name.sin_port != pdomb->dom_local_port) ) {
				int tmp, tobesaved;

				tmp = dup(tobesaved = pdomb->dom_socket);
				clnt_destroy(pdomb->dom_client);
				tobesaved = dup2(tmp, tobesaved);
				(void) close(tmp);
			} else {
				clnt_destroy(pdomb->dom_client);
				(void) close(pdomb->dom_socket);
			}

			if (pdomb == bound_domains) {
				bound_domains = pdomb->dom_pnext;
			} else {
				ptrail->dom_pnext = pdomb->dom_pnext;
			}

			free((char *) pdomb);
			break;
		}

	}


}

static char *
_default_domain()
{
	char temp[256];

	if (default_domain)
		return (default_domain);
	if (getdomainname(temp, sizeof(temp)))
		return (0);
	if (strlen(temp) > 0) {
		default_domain = (char *)malloc(strlen(temp)+1);
		if (default_domain == 0)
			return (0);
		strcpy(default_domain, temp);
		return (default_domain);
	}
	return (0);
}

/*
 * This is a wrapper for the system call getdomainname which returns a
 * ypclnt.h error code in the failure case.  It also checks to see that
 * the domain name is non-null, knowing that the null string is going to
 * get rejected elsewhere in the NIS client package.
 */
int
yp_get_default_domain(domain)
	char **domain;
{

	if ((*domain = _default_domain()) != 0)
		return (0);
	return (YPERR_YPERR);
}

/*
 * This checks to see if this is a new process incarnation which has
 * inherited bindings from a parent, and unbinds the world if so.
 */
static void
newborn()
{
	static long int mypid;	/* Cached to detect forks */
	long int testpid;

	if ((testpid = getpid() ) != mypid) {
		mypid = testpid;

		while (bound_domains) {
			_yp_unbind(bound_domains->dom_domain, FALSE);
			/*do not unmap the file*/
		}
	}
}

/*
 * This checks that the socket for a domain which has already been bound
 * hasn't been closed or changed under us.  If it has, unbind the domain
 * without closing the socket, which may be in use by some higher level
 * code.  This returns TRUE and points the binding parameter at the found
 * dom_binding if the binding is found and the socket looks OK, and FALSE