xref: /csrg-svn/sbin/mountd/mountd.c (revision 44690)

/*
 * Copyright (c) 1989 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Rick Macklem at The University of Guelph.
 *
 * %sccs.include.redist.c%
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1989 Regents of the University of California.\n\
 All rights reserved.\n";
#endif not lint

#ifndef lint
static char sccsid[] = "@(#)mountd.c	5.11 (Berkeley) 06/29/90";
#endif not lint

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <sys/mount.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/signal.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <netdb.h>
#include <rpc/rpc.h>
#include <rpc/pmap_clnt.h>
#include <rpc/pmap_prot.h>
#include <nfs/rpcv2.h>
#include <nfs/nfsv2.h>
#include "pathnames.h"

struct ufid {
	u_short	ufid_len;
	ino_t	ufid_ino;
	long	ufid_gen;
};
/*
 * Structures for keeping the mount list and export list
 */
struct mountlist {
	struct mountlist *ml_next;
	char	ml_host[RPCMNT_NAMELEN+1];
	char	ml_dirp[RPCMNT_PATHLEN+1];
};

struct exportlist {
	struct exportlist *ex_next;
	struct exportlist *ex_prev;
	struct grouplist *ex_groups;
	int	ex_rootuid;
	int	ex_exflags;
	dev_t	ex_dev;
	char	ex_dirp[RPCMNT_PATHLEN+1];
};

struct grouplist {
	struct grouplist *gr_next;
	struct hostent *gr_hp;
};

/* Global defs */
int xdr_fhs(), xdr_mlist(), xdr_dir(), xdr_explist();
int mntsrv(), get_exportlist(), send_umntall(), umntall_each();
void get_mountlist(), add_mlist(), del_mlist();
struct exportlist exphead;
struct mountlist *mlhead;
char exname[MAXPATHLEN];
int def_rootuid = -2;
int root_only = 1;
extern int errno;
#ifdef DEBUG
int debug = 1;
#else
int debug = 0;
#endif

/*
 * Mountd server for NFS mount protocol as described in:
 * NFS: Network File System Protocol Specification, RFC1094, Appendix A
 * The optional arguments are the exports file name
 * default: _PATH_EXPORTS
 * and "-n" to allow nonroot mount.
 */
main(argc, argv)
	int argc;
	char **argv;
{
	SVCXPRT *transp;
	int c;
	extern int optind;
	extern char *optarg;

	while ((c = getopt(argc, argv, "n")) != EOF)
		switch (c) {
		case 'n':
			root_only = 0;
			break;
		default:
			fprintf(stderr, "Usage: mountd [-n] [export_file]\n");
			exit(1);
		};
	argc -= optind;
	argv += optind;
	exphead.ex_next = exphead.ex_prev = (struct exportlist *)0;
	mlhead = (struct mountlist *)0;
	if (argc == 1) {
		strncpy(exname, *argv, MAXPATHLEN-1);
		exname[MAXPATHLEN-1] = '\0';
	} else
		strcpy(exname, _PATH_EXPORTS);
	openlog("mountd:", LOG_PID, LOG_DAEMON);
	get_exportlist();
	get_mountlist();
	if (debug == 0) {
		daemon(0, 0);
		signal(SIGINT, SIG_IGN);
		signal(SIGQUIT, SIG_IGN);
	}
	signal(SIGHUP, get_exportlist);
	signal(SIGTERM, send_umntall);
	{ FILE *pidfile = fopen(_PATH_MOUNTDPID, "w");
	  if (pidfile != NULL) {
		fprintf(pidfile, "%d\n", getpid());
		fclose(pidfile);
	  }
	}
	if ((transp = svcudp_create(RPC_ANYSOCK)) == NULL) {
		syslog(LOG_ERR, "Can't create socket");
		exit(1);
	}
	pmap_unset(RPCPROG_MNT, RPCMNT_VER1);
	if (!svc_register(transp, RPCPROG_MNT, RPCMNT_VER1, mntsrv, IPPROTO_UDP)) {
		syslog(LOG_ERR, "Can't register mount");
		exit(1);
	}
	svc_run();
	syslog(LOG_ERR, "Mountd died");
	exit(1);
}

/*
 * The mount rpc service
 */
mntsrv(rqstp, transp)
	register struct svc_req *rqstp;
	register SVCXPRT *transp;
{
	register struct grouplist *grp;
	register u_long **addrp;
	register struct exportlist *ep;
	nfsv2fh_t nfh;
	struct authunix_parms *ucr;
	struct stat stb;
	struct hostent *hp;
	u_long saddr;
	char dirpath[RPCMNT_PATHLEN+1];
	int bad = ENOENT;
	int omask;
	uid_t uid = -2;

	/* Get authorization */
	switch (rqstp->rq_cred.oa_flavor) {
	case AUTH_UNIX:
		ucr = (struct authunix_parms *)rqstp->rq_clntcred;
		uid = ucr->aup_uid;
		break;
	case AUTH_NULL:
	default:
		break;
	}

	saddr = transp->xp_raddr.sin_addr.s_addr;
	hp = (struct hostent *)0;
	switch (rqstp->rq_proc) {
	case NULLPROC:
		if (!svc_sendreply(transp, xdr_void, (caddr_t)0))
			syslog(LOG_ERR, "Can't send reply");
		return;
	case RPCMNT_MOUNT:
		if (uid != 0 && root_only) {
			svcerr_weakauth(transp);
			return;
		}
		if (!svc_getargs(transp, xdr_dir, dirpath)) {
			svcerr_decode(transp);
			return;
		}

		/* Check to see if it's a valid dirpath */
		if (stat(dirpath, &stb) < 0 || (stb.st_mode&S_IFMT) !=
			S_IFDIR) {
			if (!svc_sendreply(transp, xdr_long, (caddr_t)&bad))
				syslog(LOG_ERR, "Can't send reply");
			return;
		}

		/* Check in the exports list */
		omask = sigblock(sigmask(SIGHUP));
		ep = exphead.ex_next;
		while (ep != NULL) {
			if (!strcmp(ep->ex_dirp, dirpath)) {
				grp = ep->ex_groups;
				if (grp == NULL)
					break;

				/* Check for a host match */
				addrp = (u_long **)grp->gr_hp->h_addr_list;
				for (;;) {
					if (**addrp == saddr)
						break;
					if (*++addrp == NULL)
						if (grp = grp->gr_next) {
							addrp = (u_long **)
								grp->gr_hp->h_addr_list;
						} else {
							bad = EACCES;
							if (!svc_sendreply(transp, xdr_long, (caddr_t)&bad))
								syslog(LOG_ERR, "Can't send reply");
							sigsetmask(omask);
							return;
						}
				}
				hp = grp->gr_hp;
				break;
			}
			ep = ep->ex_next;
		}
		sigsetmask(omask);
		if (ep == NULL) {
			bad = EACCES;
			if (!svc_sendreply(transp, xdr_long, (caddr_t)&bad))
				syslog(LOG_ERR, "Can't send reply");
			return;
		}

		/* Get the file handle */
		bzero((caddr_t)&nfh, sizeof(nfh));
		if (getfh(dirpath, (fhandle_t *)&nfh) < 0) {
			bad = errno;
			if (!svc_sendreply(transp, xdr_long, (caddr_t)&bad))
				syslog(LOG_ERR, "Can't send reply");
			return;
		}
		if (!svc_sendreply(transp, xdr_fhs, (caddr_t)&nfh))
			syslog(LOG_ERR, "Can't send reply");
		if (hp == NULL)
			hp = gethostbyaddr((caddr_t)&saddr, sizeof(saddr), AF_INET);
		if (hp)
			add_mlist(hp->h_name, dirpath);
		return;
	case RPCMNT_DUMP:
		if (!svc_sendreply(transp, xdr_mlist, (caddr_t)0))
			syslog(LOG_ERR, "Can't send reply");
		return;
	case RPCMNT_UMOUNT:
		if (uid != 0 && root_only) {
			svcerr_weakauth(transp);
			return;
		}
		if (!svc_getargs(transp, xdr_dir, dirpath)) {
			svcerr_decode(transp);
			return;
		}
		if (!svc_sendreply(transp, xdr_void, (caddr_t)0))
			syslog(LOG_ERR, "Can't send reply");
		hp = gethostbyaddr((caddr_t)&saddr, sizeof(saddr), AF_INET);
		if (hp)
			del_mlist(hp->h_name, dirpath);
		return;
	case RPCMNT_UMNTALL:
		if (uid != 0 && root_only) {
			svcerr_weakauth(transp);
			return;
		}
		if (!svc_sendreply(transp, xdr_void, (caddr_t)0))
			syslog(LOG_ERR, "Can't send reply");
		hp = gethostbyaddr((caddr_t)&saddr, sizeof(saddr), AF_INET);
		if (hp)
			del_mlist(hp->h_name, (char *)0);
		return;
	case RPCMNT_EXPORT:
		if (!svc_sendreply(transp, xdr_explist, (caddr_t)0))
			syslog(LOG_ERR, "Can't send reply");
		return;
	default:
		svcerr_noproc(transp);
		return;
	}
}

/*
 * Xdr conversion for a dirpath string
 */
xdr_dir(xdrsp, dirp)
	XDR *xdrsp;
	char *dirp;
{
	return (xdr_string(xdrsp, &dirp, RPCMNT_PATHLEN));
}

/*
 * Xdr routine to generate fhstatus
 */
xdr_fhs(xdrsp, nfh)
	XDR *xdrsp;
	nfsv2fh_t *nfh;
{
	int ok = 0;

	if (!xdr_long(xdrsp, &ok))
		return (0);
	return (xdr_opaque(xdrsp, (caddr_t)nfh, NFSX_FH));
}

xdr_mlist(xdrsp, cp)
	XDR *xdrsp;
	caddr_t cp;
{
	register struct mountlist *mlp;
	int true = 1;
	int false = 0;
	char *strp;

	mlp = mlhead;
	while (mlp) {
		if (!xdr_bool(xdrsp, &true))
			return (0);
		strp = &mlp->ml_host[0];
		if (!xdr_string(xdrsp, &strp, RPCMNT_NAMELEN))
			return (0);
		strp = &mlp->ml_dirp[0];
		if (!xdr_string(xdrsp, &strp, RPCMNT_PATHLEN))
			return (0);
		mlp = mlp->ml_next;
	}
	if (!xdr_bool(xdrsp, &false))
		return (0);
	return (1);
}

/*
 * Xdr conversion for export list
 */
xdr_explist(xdrsp, cp)
	XDR *xdrsp;
	caddr_t cp;
{
	register struct exportlist *ep;
	register struct grouplist *grp;
	int true = 1;
	int false = 0;
	char *strp;
	int omask;

	omask = sigblock(sigmask(SIGHUP));
	ep = exphead.ex_next;
	while (ep != NULL) {
		if (!xdr_bool(xdrsp, &true))
			goto errout;
		strp = &ep->ex_dirp[0];
		if (!xdr_string(xdrsp, &strp, RPCMNT_PATHLEN))
			goto errout;
		grp = ep->ex_groups;
		while (grp != NULL) {
			if (!xdr_bool(xdrsp, &true))
				goto errout;
			strp = grp->gr_hp->h_name;
			if (!xdr_string(xdrsp, &strp, RPCMNT_NAMELEN))
				goto errout;
			grp = grp->gr_next;
		}
		if (!xdr_bool(xdrsp, &false))
			goto errout;
		ep = ep->ex_next;
	}
	sigsetmask(omask);
	if (!xdr_bool(xdrsp, &false))
		return (0);
	return (1);
errout:
	sigsetmask(omask);
	return (0);
}

#define LINESIZ	10240
char line[LINESIZ];

/*
 * Get the export list
 */
get_exportlist()
{
	register struct hostent *hp, *nhp;
	register char **addrp, **naddrp;
	register int i;
	register struct grouplist *grp;
	register struct exportlist *ep, *ep2;
	struct ufs_args args;
	struct stat sb;
	FILE *inf;
	char *cp, *endcp;
	char savedc;
	int len, dirplen;
	int rootuid, exflags;
	u_long saddr;
	struct exportlist *fep;

	/*
	 * First, get rid of the old list
	 */
	ep = exphead.ex_next;
	while (ep != NULL) {
		ep2 = ep;
		ep = ep->ex_next;
		free_exp(ep2);
	}

	/*
	 * Read in the exports file and build the list, calling
	 * exportfs() as we go along
	 */
	exphead.ex_next = exphead.ex_prev = (struct exportlist *)0;
	if ((inf = fopen(exname, "r")) == NULL) {
		syslog(LOG_ERR, "Can't open %s", exname);
		exit(2);
	}
	while (fgets(line, LINESIZ, inf)) {
		exflags = MNT_EXPORTED;
		rootuid = def_rootuid;
		cp = line;
		nextfield(&cp, &endcp);

		/*
		 * Get file system devno and see if an entry for this
		 * file system already exists.
		 */
		savedc = *endcp;
		*endcp = '\0';
		if (stat(cp, &sb) < 0 || (sb.st_mode & S_IFMT) != S_IFDIR)
			goto err;
		fep = (struct exportlist *)0;
		ep = exphead.ex_next;
		while (ep) {
			if (ep->ex_dev == sb.st_dev) {
				fep = ep;
				break;
			}
			ep = ep->ex_next;
		}
		*endcp = savedc;

		/*
		 * Create new exports list entry
		 */
		len = endcp-cp;
		if (len <= RPCMNT_PATHLEN && len > 0) {
			ep = (struct exportlist *)malloc(sizeof(*ep));
			ep->ex_next = ep->ex_prev = (struct exportlist *)0;
			ep->ex_groups = (struct grouplist *)0;
			bcopy(cp, ep->ex_dirp, len);
			ep->ex_dirp[len] = '\0';
			dirplen = len;
		} else
			goto err;
		cp = endcp;
		nextfield(&cp, &endcp);
		len = endcp-cp;
		while (len > 0) {
			savedc = *endcp;
			*endcp = '\0';
			if (len <= RPCMNT_NAMELEN) {
				if (*cp == '-') {
				    do_opt(cp+1, fep, ep, &exflags, &rootuid);
				} else {
				    if (isdigit(*cp)) {
					saddr = inet_addr(cp);
					if (saddr == -1 ||
					    (hp = gethostbyaddr((caddr_t)&saddr,
					     sizeof(saddr), AF_INET)) == NULL)
						goto err;
				    } else if ((hp = gethostbyname(cp)) == NULL)
					goto err;
				    grp = (struct grouplist *)
					    malloc(sizeof(struct grouplist));
				    if (grp == NULL)
					    goto err;
				    nhp = grp->gr_hp = (struct hostent *)
					    malloc(sizeof(struct hostent));
				    if (nhp == NULL)
					    goto err;
				    bcopy((caddr_t)hp, (caddr_t)nhp,
					    sizeof(struct hostent));
				    i = strlen(hp->h_name)+1;
				    nhp->h_name = (char *)malloc(i);
				    if (nhp->h_name == NULL)
					    goto err;
				    bcopy(hp->h_name, nhp->h_name, i);
				    addrp = hp->h_addr_list;
				    i = 1;
				    while (*addrp++)
					    i++;
				    naddrp = nhp->h_addr_list = (char **)
					    malloc(i*sizeof(char *));
				    if (naddrp == NULL)
					    goto err;
				    addrp = hp->h_addr_list;
				    while (*addrp) {
					    *naddrp = (char *)
					        malloc(hp->h_length);
					    if (*naddrp == NULL)
						goto err;
					    bcopy(*addrp, *naddrp,
						    hp->h_length);
					    addrp++;
					    naddrp++;
				    }
				    *naddrp = (char *)0;
				    grp->gr_next = ep->ex_groups;
				    ep->ex_groups = grp;
				}
			}
			cp = endcp;
			*cp = savedc;
			nextfield(&cp, &endcp);
			len = endcp-cp;
		}
		if (fep == NULL) {
			args.fspec = 0;
			args.exflags = exflags;
			args.exroot = rootuid;
			cp = (char *)0;
			while (mount(MOUNT_UFS, ep->ex_dirp, MNT_UPDATE, &args) < 0) {
				if (cp == NULL)
					cp = ep->ex_dirp + dirplen - 1;
				else
					*cp = savedc;
				/* back up over the last component */
				while (*cp == '/' && cp > ep->ex_dirp)
					cp--;
				while (*(cp - 1) != '/' && cp > ep->ex_dirp)
					cp--;
				if (cp == ep->ex_dirp) {
					syslog(LOG_WARNING,
					      "Can't export %s", ep->ex_dirp);
					free_exp(ep);
					goto nextline;
				}
				savedc = *cp;
				*cp = '\0';
			}
			if (cp)
				*cp = savedc;
			ep->ex_rootuid = rootuid;
			ep->ex_exflags = exflags;
		} else {
			ep->ex_rootuid = fep->ex_rootuid;
			ep->ex_exflags = fep->ex_exflags;
		}
		ep->ex_dev = sb.st_dev;
		ep->ex_next = exphead.ex_next;
		ep->ex_prev = &exphead;
		if (ep->ex_next != NULL)
			ep->ex_next->ex_prev = ep;
		exphead.ex_next = ep;
nextline:
		;
	}
	fclose(inf);
	return;
err:
	syslog(LOG_ERR, "Bad Exports File, mountd Failed");
	exit(2);
}

/*
 * Parse out the next white space separated field
 */
nextfield(cp, endcp)
	char **cp;
	char **endcp;
{
	register char *p;

	p = *cp;
	while (*p == ' ' || *p == '\t')
		p++;
	if (*p == '\n' || *p == '\0') {
		*cp = *endcp = p;
		return;
	}
	*cp = p++;
	while (*p != ' ' && *p != '\t' && *p != '\n' && *p != '\0')
		p++;
	*endcp = p;
}

/*
 * Parse the option string
 */
do_opt(cpopt, fep, ep, exflagsp, rootuidp)
	register char *cpopt;
	struct exportlist *fep, *ep;
	int *exflagsp, *rootuidp;
{
	register char *cpoptarg, *cpoptend;

	while (cpopt && *cpopt) {
		if (cpoptend = index(cpopt, ','))
			*cpoptend++ = '\0';
		if (cpoptarg = index(cpopt, '='))
			*cpoptarg++ = '\0';
		if (!strcmp(cpopt, "ro") || !strcmp(cpopt, "o")) {
			if (fep && (fep->ex_exflags & MNT_EXRDONLY) == 0)
				syslog(LOG_WARNING, "ro failed for %s",
				       ep->ex_dirp);
			else
				*exflagsp |= MNT_EXRDONLY;
		} else if (!strcmp(cpopt, "root") || !strcmp(cpopt, "r")) {
			if (cpoptarg && isdigit(*cpoptarg)) {
				*rootuidp = atoi(cpoptarg);
				if (fep && fep->ex_rootuid != *rootuidp)
					syslog(LOG_WARNING,
					       "uid failed for %s",
					       ep->ex_dirp);
			} else
				syslog(LOG_WARNING,
				       "uid failed for %s",
				       ep->ex_dirp);
		} else
			syslog(LOG_WARNING, "opt %s ignored for %s", cpopt,
			       ep->ex_dirp);
		cpopt = cpoptend;
	}
}

#define	STRSIZ	(RPCMNT_NAMELEN+RPCMNT_PATHLEN+50)
/*
 * Routines that maintain the remote mounttab
 */
void get_mountlist()
{
	register struct mountlist *mlp, **mlpp;
	register char *eos, *dirp;
	int len;
	char str[STRSIZ];
	FILE *mlfile;

	if (((mlfile = fopen(_PATH_RMOUNTLIST, "r")) == NULL) &&
	    ((mlfile = fopen(_PATH_RMOUNTLIST, "w")) == NULL)) {
		syslog(LOG_WARNING, "Can't open %s", _PATH_RMOUNTLIST);
		return;
	}
	mlpp = &mlhead;
	while (fgets(str, STRSIZ, mlfile) != NULL) {
		if ((dirp = index(str, '\t')) == NULL &&
		    (dirp = index(str, ' ')) == NULL)
			continue;
		mlp = (struct mountlist *)malloc(sizeof (*mlp));
		len = dirp-str;
		if (len > RPCMNT_NAMELEN)
			len = RPCMNT_NAMELEN;
		bcopy(str, mlp->ml_host, len);
		mlp->ml_host[len] = '\0';
		while (*dirp == '\t' || *dirp == ' ')
			dirp++;
		if ((eos = index(dirp, '\t')) == NULL &&
		    (eos = index(dirp, ' ')) == NULL &&
		    (eos = index(dirp, '\n')) == NULL)
			len = strlen(dirp);
		else
			len = eos-dirp;
		if (len > RPCMNT_PATHLEN)
			len = RPCMNT_PATHLEN;
		bcopy(dirp, mlp->ml_dirp, len);
		mlp->ml_dirp[len] = '\0';
		mlp->ml_next = (struct mountlist *)0;
		*mlpp = mlp;
		mlpp = &mlp->ml_next;
	}
	fclose(mlfile);
}

void del_mlist(hostp, dirp)
	register char *hostp, *dirp;
{
	register struct mountlist *mlp, **mlpp;
	FILE *mlfile;
	int fnd = 0;

	mlpp = &mlhead;
	mlp = mlhead;
	while (mlp) {
		if (!strcmp(mlp->ml_host, hostp) &&
		    (!dirp || !strcmp(mlp->ml_dirp, dirp))) {
			fnd = 1;
			*mlpp = mlp->ml_next;
			free((caddr_t)mlp);
		}
		mlpp = &mlp->ml_next;
		mlp = mlp->ml_next;
	}
	if (fnd) {
		if ((mlfile = fopen(_PATH_RMOUNTLIST, "w")) == NULL) {
			syslog(LOG_WARNING, "Can't update %s", _PATH_RMOUNTLIST);
			return;
		}
		mlp = mlhead;
		while (mlp) {
			fprintf(mlfile, "%s %s\n", mlp->ml_host, mlp->ml_dirp);
			mlp = mlp->ml_next;
		}
		fclose(mlfile);
	}
}

void add_mlist(hostp, dirp)
	register char *hostp, *dirp;
{
	register struct mountlist *mlp, **mlpp;
	FILE *mlfile;

	mlpp = &mlhead;
	mlp = mlhead;
	while (mlp) {
		if (!strcmp(mlp->ml_host, hostp) && !strcmp(mlp->ml_dirp, dirp))
			return;
		mlpp = &mlp->ml_next;
		mlp = mlp->ml_next;
	}
	mlp = (struct mountlist *)malloc(sizeof (*mlp));
	strncpy(mlp->ml_host, hostp, RPCMNT_NAMELEN);
	mlp->ml_host[RPCMNT_NAMELEN] = '\0';
	strncpy(mlp->ml_dirp, dirp, RPCMNT_PATHLEN);
	mlp->ml_dirp[RPCMNT_PATHLEN] = '\0';
	mlp->ml_next = (struct mountlist *)0;
	*mlpp = mlp;
	if ((mlfile = fopen(_PATH_RMOUNTLIST, "a")) == NULL) {
		syslog(LOG_WARNING, "Can't update %s", _PATH_RMOUNTLIST);
		return;
	}
	fprintf(mlfile, "%s %s\n", mlp->ml_host, mlp->ml_dirp);
	fclose(mlfile);
}

/*
 * This function is called via. SIGTERM when the system is going down.
 * It sends a broadcast RPCMNT_UMNTALL.
 */
send_umntall()
{
	(void) clnt_broadcast(RPCPROG_MNT, RPCMNT_VER1, RPCMNT_UMNTALL,
		xdr_void, (caddr_t)0, xdr_void, (caddr_t)0, umntall_each);
	exit();
}

umntall_each(resultsp, raddr)
	caddr_t resultsp;
	struct sockaddr_in *raddr;
{
	return (1);
}

/*
 * Free up an exports list component
 */
free_exp(ep)
	register struct exportlist *ep;
{
	register struct grouplist *grp;
	register char **addrp;
	struct grouplist *grp2;

	grp = ep->ex_groups;
	while (grp != NULL) {
		addrp = grp->gr_hp->h_addr_list;
		while (*addrp)
			free(*addrp++);
		free((caddr_t)grp->gr_hp->h_addr_list);
		free(grp->gr_hp->h_name);
		free((caddr_t)grp->gr_hp);
		grp2 = grp;
		grp = grp->gr_next;
		free((caddr_t)grp2);
	}
	free((caddr_t)ep);
}