mountd.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 2,539 行 · 第 1/5 页

#ifndef lint
static	char	*sccsid = "@(#)mountd.c	4.7	(ULTRIX)	4/25/91";
#endif lint
/************************************************************************
 *									*
 *			Copyright (c) 1986-1990 by			*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/*
 *	Portions of this software have been licensed to 
 *	Digital Equipment Company, Maynard, MA.
 *	Copyright (c) 1987 Sun Microsystems, Inc.  ALL RIGHTS RESERVED.
 */

/***********************************************************************
 *
 *		Modification History
 *
 * 02/11/91 lebel
 *	Fixed mounting /joe/../jim security hole.  Patched spots where
 *	mountd wasn't freeing memory.  Added ip addr cache to speed up
 *	automount -hosts, modified 'imposter' (now 'getclientsname').
 *
 * 11/15/90 lebel
 *		Fixed bug with non-existant pathname parsing in
 *		set_exports.  Added smarter rmtab updating, YP netgroup
 *		caching, and duplicate requests cache.
 *
 * 07/02/90 sue
 *		Made fix to have short host names in /etc/exports.
 *
 * 11/10/89 lebel
 *		Errors now go to syslog.  Showmounts can be done over tcp 
 *		(tcp can handle arbitrarily long exports lists).  The -d
 *		option implies the -i option and the -s option implies both
 *		-i and -d.  Mountd registers itself with the portmapper 
 *		before forking to prevent the case where nfsds start up
 *		before mountd has time to register itself.  Hostname 
 *		comparisons are case insensitive.  Duplicate detection
 *		is now done by inode # comparison (to detect links).
 *
 * 07/21/89 lebel
 *		Rewrite of mtd_mount() and set_exports() to allow options at
 *		the directory level.  The -n (no filehandle) exports option
 *		is no longer employed.  update_exportfsdata() keeps the new
 *		kernel exports list in sync with the mount daemon's.
 *
 * 05/25/89	Suzanne Logcher
 *		Removed code specific to /etc/svcorder.  File is now
 *		/etc/svc.conf.  Use libc version of bindup().
 *
 * 11/16/88	Suzanne Logcher
 *		Fixed de-referencing null pointer bugs in path_check()
 *		which caused mountd on PMAX to seg fault and core dump.
 *
 * 11/10/88	Suzanne Logcher
 *		Updated with V3.0 changes.
 *
 * 07/15/88	Suzanne Logcher
 *		Fixed QAR 64 bug to continue to parse a directory entry
 *		in /etc/exports after catching an improper setting of
 *		an option.  Force a showmount request to rebuild the
 *		export structure.  Changed usage of -i with bind.  The
 *		-d flag is for after checking the IP address, see if
 *		host is in the server domain.  The -s flag does the same
 *		check but checks if the host is in the server domain or
 *		a subdomain.
 *
 * 06/09/88	Suzanne Logcher
 *		Added v2.3 fix to not cleanup the export list of
 *		unexported filesystems and use that info to determine
 *		whether the getmount info on the filesystem has changed
 *		thus giving the mountd a "kick" to rebuild the export
 *		list.  This handles the case when the filesystems have
 *		changed and the /etc/exports file has NOT been modified
 *		thus causing the mountd's export list to be out-of-date.
 *		Upon a second failure with exit with EACESS.
 *
 * 04/24/88	Fred Glover
 *		Add BIND domain specification check for ipaddr_check 
 *
 * 03/01/88	Suzanne Logcher
 *		Rewrite of code.  Use getmountent to build exports
 *		list, and then read in /etc/exports and build matrix
 *		of exports with filesystems and directories.  Change
 *		code in mtd_mount() to parse new list structure.  Add a
 *		routine, flatten_exports(), to provide full information
 *		to an EXPORT request.  Linted as best as possible.
 *
 * 05/25/87	Joe Amato
 *		When looking to match the path requested to mount
 *		loop through exports list looking for an exact match
 *		if not found, loop through exports list again, but
 *		look for a match on a subset of the requested path
 *
 * 05/19/87	Joe Amato
 *		Moved some initialization code before fork.
 *		When looking for a machine in a long group list, only 
 *		call innetgr after searching complete list to avoid 
 *		unnecessary YP timeouts.
 *
 * 05/06/87	Suzanne Logcher
 *		Changed M_RONLY to M_EXRONLY
 *
 * 03/19/87	Suzanne Logcher
 *		Added code to setopt to parse options in /etc/exports
 *
 * 02/10/87	Suzanne Logcher
 *		Added code to allow exporting of directories
 *
 ***********************************************************************/

/* NFS mount server */

#include <ctype.h>
#include <sys/param.h>
#include <ufs/fs.h>
#include <rpc/rpc.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/time.h>
#include <stdio.h>
#include <syslog.h>
#include <signal.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/dir.h>
#include <nfs/nfs.h>
#include <rpcsvc/ypclnt.h>
#include <rpcsvc/yp_prot.h>
#ifdef DEBUG
#include "mount.h"
#else
#include <rpcsvc/mount.h>
#endif DEBUG
#include <netdb.h>
#include <sys/mount.h>
#include <nfs/nfs_clnt.h>
#include <nfs/vfs.h>

#include <strings.h>
#include <arpa/nameser.h>
#include <resolv.h>

#define	EXPORTS	"/etc/exports"
#define RMTAB	"/etc/rmtab"
#define MAXRMTABLINELEN         (MAXPATHLEN + MAXHOSTNAMELEN + 2)
#define	MAXLINE	2048
#define MAX_LEVELS  10
#define MAXADDRS 8

extern int errno;

int expand_ng();
int innetgr_cache();
int check_ng();
int getkeys();
int mnt();
char *exmalloc();
struct exports *newex();
struct groups *newgroup();
char *goto_char();
char *realpath();

/*
 * mountd's version of a "struct mountlist". It is the same except
 * for the added ml_pos field.
 */
struct mountdlist {
/* same as XDR mountlist */
        char *ml_name;
        char *ml_path;
        struct mountdlist *ml_nxt;
/* private to mountd */
        long ml_pos;            /* position of mount entry in RMTAB */
};

struct ng {             /* netgroup cache */
        long ng_stamp;
        char *ng_name;
        struct hlist *ng_hosts;
        struct ng *next_ng;
        struct ng *prev_ng;
};

struct hlist {
        char *hname;
        struct hlist *next_host;
};

/*
 * Mount Reply Cache - save replies, and check the cache to catch
 * retransmitted requests.
 */

/*
 *  RPC server duplicate transaction cache flag values
 */
#define DUP_BUSY        0x1     /* transaction in progress */
#define DUP_DONE        0x2     /* transaction was completed */
#define DUP_FAIL        0x4     /* transaction failed */

struct dupreq {
        struct in_addr  rc_addr;        /* client address */
        u_short         rc_flags;       /* DUP_BUSY, DUP_DONE, DUP_FAIL */
        dev_t           rc_dev;         /* device */
        u_long          rc_ino;         /* inode number */
        u_long          rc_gen;         /* generation number */
        struct dupreq   *rc_next;       /* linked list of all entries */
        struct dupreq   *rc_chain;      /* hash chain */
	char 		*rc_ancname;    /* name of requested path's most
					   closely related exported ancestor */
};

#define KEYHASH(addr,dev,ino,gen)       ((((addr) ^ (dev)) ^ (ino) ^ (gen)) % drhashszminus1)
#define KEYTOLIST(addr,dev,ino,gen)     ((struct dupreq *)(drhashtbl[KEYHASH(addr,dev,ino,gen)]))
#define REQTOLIST(dr)   KEYTOLIST((dr)->rc_addr.s_addr,(dr)->rc_dev,(dr)->rc_ino, (dr)->rc_gen)
 
/* routine to compare dup cache entries */
#define NOTDUP(dr, addr,dev,ino,gen) (dr->rc_addr.s_addr != addr || \
                            dr->rc_dev != dev || \
                            dr->rc_ino != ino || \
                            dr->rc_gen != gen)

/*
 * dupcache_max is the number of cached items.  It is set
 * based on "system size". It should be large enough to hold
 * transaction history long enough so that a given entry is still
 * around for a few retransmissions of that transaction.
 */
#define MINDUPREQS      1024
#define MAXDUPREQS      4096
struct dupreq **drhashtbl; /* array of heads of hash lists */
int drhashsz;              /* number of hash lists */
int drhashszminus1;        /* hash modulus */
int dupcache_max;
struct dupreq *dupreqcache, *drmru;
struct dupreq *dupcache_check();

struct ng *nglist = NULL;  /* head of netgroup's cache */
char *ng_names[100];
int num_ngs;
static struct mountdlist *mountlist;
int rmtab_load();
long rmtab_insert();
 
char myname[BUFSIZ];
char mydomain[MAXNAMLEN+1];
char *pgmname;
char *exportfile = EXPORTS;
struct stat exportstat;
struct exports *exports = NULL;
struct exports *flatexports = NULL;
int nfs_portmon = 0;
int ipaddr_check = 0;
int domain_check = 0;
int subdomain_check = 0;

struct timeval rmtab_written, now;
struct timezone tz;
/*
 * resync rmtab no more often than at 30 minute intervals
 * sole purpose is to get rid of commented out (unmounted) entries
 */
int   rmtab_sync=1800;

/*
 * Cached netgroups are assumed correct for at least 15 minutes
 */
int ngtimeout = 900;
 
main(argc, argv)
char	*argv[];
{
	SVCXPRT *transp;
	char *strchr ();
	int fd; /* open fd of rmtab */

	pgmname = argv[0];

	/*
	 * must be superuser to run 
	 */
	if (geteuid() != 0){
		(void) fprintf(stderr, "%s:  must be super user\n", pgmname);
		(void) fflush(stderr);
		exit(1);
	}
	while (--argc > 0 ) {
		*++argv;
		if ((*argv)[0] != '-' || strlen(*argv) != 2) {
			usage();
		}

		switch ((*argv)[1]) {
		case 'i':
			ipaddr_check++;
			break;
		case 'd':
			ipaddr_check++;
			domain_check++;
			break;
		case 's':
			ipaddr_check++;
			subdomain_check++;
			break;
		default:
			usage();
		}
	}
	if (openlog("mountd", LOG_PID) < 0)
		fprintf(stderr, "mountd: openlog failed\n");
	syslog(LOG_ERR, "startup");

	/*
	 * Initalize the world
	 */
	if(gethostname(myname, sizeof(myname)) < 0){            /* jaa */
		syslog(LOG_ERR, "gethostname: %m");
		exit(1);
	}
	if(getdomainname(mydomain, sizeof(mydomain)) < 0){      /* jaa */
		syslog(LOG_ERR, "getdomainname: %m");
		exit(1);
	}

	/*
	 * Read rmtab and exports files, build netgroups cache
	 */
	fd = rmtab_load();
	if (mydomain[0] != NULL)
        	build_ngcache();
#ifdef DEBUG
        print_ngcache();
#endif DEBUG
	set_exports();
#ifdef DEBUG
	(void) fprintf(stderr, "*** finished loading export list ***\n");
#endif DEBUG
	gettimeofday(&rmtab_written, &tz);

	/*
	 * Remove this chunk of code if we ever run under inetd.
         * (Make sure rmtab - fd - does not get closed)
	 * Also remove the mtd_abort() routine if running under inetd.
	 */
	{
		int s, t;
		struct sockaddr_in addr;
		int len = sizeof(struct sockaddr_in);
		int pid;

#ifndef DEBUG
		for (t = 0; t < 20; t++)
			if (t != fd)
				(void) close(t);
	 	open("/", 0);
	 	dup2(0, 1);
	 	dup2(0, 2);
#endif DEBUG
		if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
			syslog(LOG_ERR, "socket: %m");
			exit(1);
		}
		if (bind(s, &addr, sizeof(addr)) < 0) {
			syslog(LOG_ERR, "bind: %m");
			exit(1);
		}
		if (getsockname(s, &addr, &len) != 0) {
			syslog(LOG_ERR, "getsockname: %m");
			(void) close(s);
			exit(1);
		}
		pmap_unset(MOUNTPROG, MOUNTVERS);
		/* 
		 * register with portmapper if not started from inetd
		 */
		pmap_set(MOUNTPROG, MOUNTVERS, IPPROTO_UDP,
		    ntohs(addr.sin_port));
		if (dup2(s, 0) < 0) {
			syslog(LOG_ERR, "dup2: %m");
			exit(1);
		}
#ifndef DEBUG
		pid = fork();
		if (pid < 0) {
			syslog(LOG_ERR, "Cannot fork: %m");
			exit(1);
		}
		if (pid != 0)
			exit(0);
#endif DEBUG
	}

	/* End chunk to remove if running under inetd. */

	/*
	 * Create UDP service
	 */
	if ((transp = svcudp_create(0)) == NULL) {
		syslog(LOG_ERR, "couldn't create UDP transport");
		exit(1);
	}
	if (!svc_register(transp, MOUNTPROG, MOUNTVERS, mnt, 0)) {
		syslog(LOG_ERR, "couldn't register MOUNTPROG");
		exit(1);
	}

	/*
	 * Create TCP service
	 */
	if ((transp = svctcp_create(RPC_ANYSOCK, 0, 0)) == NULL) {
		syslog(LOG_ERR, "couldn't create TCP transport");
		exit(1);
	}
	if (!svc_register(transp, MOUNTPROG, MOUNTVERS, mnt, IPPROTO_TCP)) {
		syslog(LOG_ERR, "couldn't register MOUNTPROG");
		exit(1);
	}

	dupcache_init();  /* dup req cache */
	/*
	 * Start serving
	 */

	while(1) {
		svc_run();
		syslog(LOG_ERR, "Error: svc_run shouldn't have returned");
		mtd_abort();
	}
}

/*
 * Server procedure switch routine
 */
mnt(rqstp, transp)
	struct svc_req *rqstp;
	SVCXPRT *transp;
{
#ifdef DEBUG
	char *machine;

	machine = ((struct authunix_parms *) rqstp->rq_clntcred)->aup_machname;
#endif DEBUG
	switch(rqstp->rq_proc) {
		case NULLPROC:
			if (!svc_sendreply(transp, xdr_void, NULL)) {
				syslog(LOG_ERR, "couldn't reply to NULL rpc call");
				mtd_abort();
			}
			return;
		case MOUNTPROC_MNT:
#ifdef DEBUG
			(void) fprintf(stderr, "about to do a mount from %s\n", machine);
#endif
			set_exports();
			(void) mtd_mount(rqstp, transp);
			return;
		case MOUNTPROC_DUMP:
#ifdef DEBUG
			(void) fprintf(stderr, "about to do a dump from %s\n", machine);
#endif
			if (!svc_sendreply(transp, xdr_mountlist, &mountlist)) {
				syslog(LOG_ERR, "couldn't reply to DUMP rpc call");
				mtd_abort();
			}
			return;
		case MOUNTPROC_UMNT:
#ifdef DEBUG
			(void) fprintf(stderr, "about to do an unmount from %s\n", machine);
#endif
			(void) mtd_umount(rqstp, transp);
			return;
		case MOUNTPROC_UMNTALL:
#ifdef DEBUG
			(void) fprintf(stderr, "about to do an unmountall from %s\n", machine);
#endif
			mtd_umountall(rqstp, transp);
			return;
		case MOUNTPROC_EXPORT:
		case MOUNTPROC_EXPORTALL:
#ifdef DEBUG
			(void) fprintf(stderr, "about to do an export from %s\n", machine);