nfsmount.c

linux mount的源代码

				nocto = !val;
			else if (!strcmp(opt, "ac"))
				noac = !val;
			else if (!strcmp(opt, "tcp"))
				tcp = val;
			else if (!strcmp(opt, "udp"))
				tcp = !val;
			else if (!strcmp(opt, "lock")) {
				if (nfs_mount_version >= 3)
					nolock = !val;
				else
					printf(_("Warning: option nolock is not supported.\n"));
			} else {
				printf(_("unknown nfs mount option: "
					   "%s%s\n"), val ? "" : "no", opt);
				goto fail;
			}
		}
	}
	proto = (tcp) ? IPPROTO_TCP : IPPROTO_UDP;

	data.flags = (soft ? NFS_MOUNT_SOFT : 0)
		| (intr ? NFS_MOUNT_INTR : 0)
		| (posix ? NFS_MOUNT_POSIX : 0)
		| (nocto ? NFS_MOUNT_NOCTO : 0)
		| (noac ? NFS_MOUNT_NOAC : 0);
#if NFS_MOUNT_VERSION >= 2
	if (nfs_mount_version >= 2)
		data.flags |= (tcp ? NFS_MOUNT_TCP : 0);
#endif
#if NFS_MOUNT_VERSION >= 3
	if (nfs_mount_version >= 3)
		data.flags |= (nolock ? NFS_MOUNT_NONLM : 0);
#endif
	if (nfsvers > MAX_NFSPROT) {
		error_msg("NFSv%d not supported!", nfsvers);
		return 0;
	}
	if (mountvers > MAX_NFSPROT) {
		error_msg("NFSv%d not supported!", nfsvers);
		return 0;
	}
	if (nfsvers && !mountvers)
		mountvers = (nfsvers < 3) ? 1 : nfsvers;
	if (nfsvers && nfsvers < mountvers) {
		mountvers = nfsvers;
	}

	/* Adjust options if none specified */
	if (!data.timeo)
		data.timeo = tcp ? 70 : 7;

#ifdef NFS_MOUNT_DEBUG
	printf("rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
		data.rsize, data.wsize, data.timeo, data.retrans);
	printf("acreg (min, max) = (%d, %d), acdir (min, max) = (%d, %d)\n",
		data.acregmin, data.acregmax, data.acdirmin, data.acdirmax);
	printf("port = %d, bg = %d, retry = %d, flags = %.8x\n",
		port, bg, retry, data.flags);
	printf("mountprog = %d, mountvers = %d, nfsprog = %d, nfsvers = %d\n",
		mountprog, mountvers, nfsprog, nfsvers);
	printf("soft = %d, intr = %d, posix = %d, nocto = %d, noac = %d\n",
		(data.flags & NFS_MOUNT_SOFT) != 0,
		(data.flags & NFS_MOUNT_INTR) != 0,
		(data.flags & NFS_MOUNT_POSIX) != 0,
		(data.flags & NFS_MOUNT_NOCTO) != 0,
		(data.flags & NFS_MOUNT_NOAC) != 0);
#if NFS_MOUNT_VERSION >= 2
	printf("tcp = %d\n",
		(data.flags & NFS_MOUNT_TCP) != 0);
#endif
#endif

	data.version = nfs_mount_version;
	*mount_opts = (char *) &data;

	if (*flags & MS_REMOUNT)
		return 0;

	/*
	 * If the previous mount operation on the same host was
	 * backgrounded, and the "bg" for this mount is also set,
	 * give up immediately, to avoid the initial timeout.
	 */
	if (bg && !running_bg &&
	    prev_bg_host && strcmp(hostname, prev_bg_host) == 0) {
		if (retry > 0)
			retval = EX_BG;
		return retval;
	}

	/* create mount deamon client */
	/* See if the nfs host = mount host. */
	if (mounthost) {
	  if (mounthost[0] >= '0' && mounthost[0] <= '9') {
	    mount_server_addr.sin_family = AF_INET;
	    mount_server_addr.sin_addr.s_addr = inet_addr(hostname);
	  } else {
#ifdef NO_GETHOSTBYNAME
		  fprintf(stderr, "ERROR (%d): no gethostbyname()\n", __LINE__);
#else
		  if ((hp = gethostbyname(mounthost)) == NULL) {
			  error_msg("can't get address for %s", hostname);
			  goto fail;
		  } else {
			  if (hp->h_length > sizeof(struct in_addr)) {
				  error_msg("got bad hp->h_length?");
				  hp->h_length = sizeof(struct in_addr);
			  }
			  mount_server_addr.sin_family = AF_INET;
			  memcpy(&mount_server_addr.sin_addr,
				 hp->h_addr, hp->h_length);
		  }
#endif
	  }
	}

	/*
	 * The following loop implements the mount retries. On the first
	 * call, "running_bg" is 0. When the mount times out, and the
	 * "bg" option is set, the exit status EX_BG will be returned.
	 * For a backgrounded mount, there will be a second call by the
	 * child process with "running_bg" set to 1.
	 *
	 * The case where the mount point is not present and the "bg"
	 * option is set, is treated as a timeout. This is done to
	 * support nested mounts.
	 *
	 * The "retry" count specified by the user is the number of
	 * minutes to retry before giving up.
	 *
	 * Only the first error message will be displayed.
	 */
	retry_timeout.tv_sec = 3;
	retry_timeout.tv_usec = 0;
	total_timeout.tv_sec = 20;
	total_timeout.tv_usec = 0;
	timeout = time(NULL) + 60 * retry;
	prevt = 0;
	t = 30;
	val = 1;
	for (;;) {
		if (bg && stat(node, &statbuf) == -1) {
			if (running_bg) {
				sleep(val);	/* 1, 2, 4, 8, 16, 30, ... */
				val *= 2;
				if (val > 30)
					val = 30;
			}
		} else {
			/* be careful not to use too many CPU cycles */
			if (t - prevt < 30)
				sleep(30);

			pm_mnt = get_mountport(&mount_server_addr,
				       mountprog,
				       mountvers,
				       proto,
 				       mountport);

			/* contact the mount daemon via TCP */
			mount_server_addr.sin_port = htons(pm_mnt->pm_port);
			msock = RPC_ANYSOCK;

			switch (pm_mnt->pm_prot) {
			case IPPROTO_UDP:
				mclient = clntudp_create(&mount_server_addr,
						 pm_mnt->pm_prog,
						 pm_mnt->pm_vers,
						 retry_timeout,
						 &msock);
		  if (mclient)
			  break;
		  mount_server_addr.sin_port = htons(pm_mnt->pm_port);
		  msock = RPC_ANYSOCK;
		case IPPROTO_TCP:
			mclient = clnttcp_create(&mount_server_addr,
						 pm_mnt->pm_prog,
						 pm_mnt->pm_vers,
						 &msock, 0, 0);
			break;
		default:
			mclient = 0;
			}
			if (mclient) {
				/* try to mount hostname:dirname */
				mclient->cl_auth = authunix_create_default();

			/* make pointers in xdr_mountres3 NULL so
			 * that xdr_array allocates memory for us
			 */
			memset(&status, 0, sizeof(status));

			if (pm_mnt->pm_vers == 3)
				clnt_stat = clnt_call(mclient, MOUNTPROC3_MNT,
						      (xdrproc_t) xdr_dirpath,
						      (caddr_t) &dirname,
						      (xdrproc_t) xdr_mountres3,
						      (caddr_t) &status,
					total_timeout);
			else
				clnt_stat = clnt_call(mclient, MOUNTPROC_MNT,
						      (xdrproc_t) xdr_dirpath,
						      (caddr_t) &dirname,
						      (xdrproc_t) xdr_fhstatus,
						      (caddr_t) &status,
						      total_timeout);

				if (clnt_stat == RPC_SUCCESS)
					break;		/* we're done */
				if (errno != ECONNREFUSED) {
					clnt_perror(mclient, "mount");
					goto fail;	/* don't retry */
				}
				if (!running_bg && prevt == 0)
					clnt_perror(mclient, "mount");
				auth_destroy(mclient->cl_auth);
				clnt_destroy(mclient);
				mclient = 0;
				close(msock);
			} else {
				if (!running_bg && prevt == 0)
					clnt_pcreateerror("mount");
			}
			prevt = t;
		}
		if (!bg)
		        goto fail;
		if (!running_bg) {
			prev_bg_host = xstrdup(hostname);
			if (retry > 0)
				retval = EX_BG;
			goto fail;
		}
		t = time(NULL);
		if (t >= timeout)
			goto fail;
	}
	nfsvers = (pm_mnt->pm_vers < 2) ? 2 : pm_mnt->pm_vers;

	if (nfsvers == 2) {
		if (status.nfsv2.fhs_status != 0) {
			error_msg("%s:%s failed, reason given by server: %s",
				hostname, dirname,
				nfs_strerror(status.nfsv2.fhs_status));
			goto fail;
		}
		memcpy(data.root.data,
		       (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
		       NFS_FHSIZE);
#if NFS_MOUNT_VERSION >= 4
		data.root.size = NFS_FHSIZE;
		memcpy(data.old_root.data,
		       (char *) status.nfsv2.fhstatus_u.fhs_fhandle,
		       NFS_FHSIZE);
#endif
	} else {
#if NFS_MOUNT_VERSION >= 4
		fhandle3 *my_fhandle;
		if (status.nfsv3.fhs_status != 0) {
			error_msg("%s:%s failed, reason given by server: %s",
				hostname, dirname,
				nfs_strerror(status.nfsv3.fhs_status));
			goto fail;
		}
		my_fhandle = &status.nfsv3.mountres3_u.mountinfo.fhandle;
		memset(data.old_root.data, 0, NFS_FHSIZE);
		memset(&data.root, 0, sizeof(data.root));
		data.root.size = my_fhandle->fhandle3_len;
		memcpy(data.root.data,
		       (char *) my_fhandle->fhandle3_val,
		       my_fhandle->fhandle3_len);

		data.flags |= NFS_MOUNT_VER3;
#endif
	}

	/* create nfs socket for kernel */

	if (tcp) {
		if (nfs_mount_version < 3) {
	     		printf(_("NFS over TCP is not supported.\n"));
			goto fail;
		}
		fsock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	} else
		fsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (fsock < 0) {
		perror(_("nfs socket"));
		goto fail;
	}
	if (bindresvport(fsock, 0) < 0) {
		perror(_("nfs bindresvport"));
		goto fail;
	}
	if (port == 0) {
		server_addr.sin_port = PMAPPORT;
		port = pmap_getport(&server_addr, nfsprog, nfsvers,
			tcp ? IPPROTO_TCP : IPPROTO_UDP);
		if (port == 0)
			port = NFS_PORT;
#ifdef NFS_MOUNT_DEBUG
		else
			printf(_("used portmapper to find NFS port\n"));
#endif
	}
#ifdef NFS_MOUNT_DEBUG
	printf(_("using port %d for nfs deamon\n"), port);
#endif
	server_addr.sin_port = htons(port);
	 /*
	  * connect() the socket for kernels 1.3.10 and below only,
	  * to avoid problems with multihomed hosts.
	  * --Swen
	  */
	if (get_kernel_revision() <= 66314
	    && connect(fsock, (struct sockaddr *) &server_addr,
		       sizeof (server_addr)) < 0) {
		perror(_("nfs connect"));
		goto fail;
	}

	/* prepare data structure for kernel */

	data.fd = fsock;
	memcpy((char *) &data.addr, (char *) &server_addr, sizeof(data.addr));
	strncpy(data.hostname, hostname, sizeof(data.hostname));

	/* clean up */

	auth_destroy(mclient->cl_auth);
	clnt_destroy(mclient);
	close(msock);
	return 0;

	/* abort */

fail:
	if (msock != -1) {
		if (mclient) {
			auth_destroy(mclient->cl_auth);
			clnt_destroy(mclient);
		}
		close(msock);
	}
	if (fsock != -1)
		close(fsock);
	return retval;
}	

/*
 * We need to translate between nfs status return values and
 * the local errno values which may not be the same.
 *
 * Andreas Schwab <[e-mail]>: change errno:
 * "after #include <errno.h> the symbol errno is reserved for any use,
 *  it cannot even be used as a struct tag or field name".
 */

#ifndef EDQUOT
#define EDQUOT	ENOSPC
#endif

static struct {
	enum nfs_stat stat;
	int errnum;
} nfs_errtbl[] = {
	{ NFS_OK,		0		},
	{ NFSERR_PERM,		EPERM		},
	{ NFSERR_NOENT,		ENOENT		},
	{ NFSERR_IO,		EIO		},
	{ NFSERR_NXIO,		ENXIO		},
	{ NFSERR_ACCES,		EACCES		},
	{ NFSERR_EXIST,		EEXIST		},
	{ NFSERR_NODEV,		ENODEV		},
	{ NFSERR_NOTDIR,	ENOTDIR		},
	{ NFSERR_ISDIR,		EISDIR		},
#ifdef NFSERR_INVAL
	{ NFSERR_INVAL,		EINVAL		},	/* that Sun forgot */
#endif
	{ NFSERR_FBIG,		EFBIG		},
	{ NFSERR_NOSPC,		ENOSPC		},
	{ NFSERR_ROFS,		EROFS		},
	{ NFSERR_NAMETOOLONG,	ENAMETOOLONG	},
	{ NFSERR_NOTEMPTY,	ENOTEMPTY	},
	{ NFSERR_DQUOT,		EDQUOT		},
	{ NFSERR_STALE,		ESTALE		},
#ifdef EWFLUSH
	{ NFSERR_WFLUSH,	EWFLUSH		},
#endif
	/* Throw in some NFSv3 values for even more fun (HP returns these) */
	{ 71,			EREMOTE		},

	{ -1,			EIO		}
};

static char *nfs_strerror(int status)
{
	int i;
	static char buf[256];

	for (i = 0; nfs_errtbl[i].stat != -1; i++) {
		if (nfs_errtbl[i].stat == status)
			return strerror(nfs_errtbl[i].errnum);
	}
	sprintf(buf, _("unknown nfs status return value: %d"), status);
	return buf;
}

static bool_t
xdr_fhandle (XDR *xdrs, fhandle objp)
{
	//register int32_t *buf;

	 if (!xdr_opaque (xdrs, objp, FHSIZE))
		 return FALSE;
	return TRUE;
}

bool_t
xdr_fhstatus (XDR *xdrs, fhstatus *objp)
{
	//register int32_t *buf;

	 if (!xdr_u_int (xdrs, &objp->fhs_status))
		 return FALSE;
	switch (objp->fhs_status) {
	case 0:
		 if (!xdr_fhandle (xdrs, objp->fhstatus_u.fhs_fhandle))
			 return FALSE;
		break;
	default:
		break;
	}
	return TRUE;
}

bool_t
xdr_dirpath (XDR *xdrs, dirpath *objp)
{
	//register int32_t *buf;

	 if (!xdr_string (xdrs, objp, MNTPATHLEN))
		 return FALSE;
	return TRUE;
}

bool_t
xdr_fhandle3 (XDR *xdrs, fhandle3 *objp)
{
	//register int32_t *buf;

	 if (!xdr_bytes (xdrs, (char **)&objp->fhandle3_val, (u_int *) &objp->fhandle3_len, FHSIZE3))
		 return FALSE;
	return TRUE;
}

#ifdef TOOL_CHAIN

/*
 * XDR integers
 */
bool_t
_xdr_int(xdrs, ip)
     XDR *xdrs;
     int *ip;
{

#ifdef lint
  (void) (xdr_short(xdrs, (short *)ip));
  return (xdr_long(xdrs, (long *)ip));
#else
  if (sizeof (int) == sizeof (long)) {
    return (xdr_long(xdrs, (long *)ip));
  } else {
    return (xdr_short(xdrs, (short *)ip));
  }
#endif
}

#endif   /* TOOL_CHAIN */

bool_t
xdr_mountres3_ok (XDR *xdrs, mountres3_ok *objp)
{
	//register int32_t *buf;

	 if (!xdr_fhandle3 (xdrs, &objp->fhandle))
		 return FALSE;
	 if (!xdr_array (xdrs, (char **)&objp->auth_flavours.auth_flavours_val, (u_int *) &objp->auth_flavours.auth_flavours_len, ~0,
			 sizeof (int), (xdrproc_t) _xdr_int))   /* xdr_int --> _xdr_int */
		 return FALSE;
	return TRUE;
}

bool_t
xdr_mountstat3 (XDR *xdrs, mountstat3 *objp)
{
	//register int32_t *buf;

	 if (!xdr_enum (xdrs, (enum_t *) objp))
		 return FALSE;
	return TRUE;
}

bool_t
xdr_mountres3 (XDR *xdrs, mountres3 *objp)
{
	//register int32_t *buf;

	 if (!xdr_mountstat3 (xdrs, &objp->fhs_status))
		 return FALSE;
	switch (objp->fhs_status) {
	case MNT_OK:
		 if (!xdr_mountres3_ok (xdrs, &objp->mountres3_u.mountinfo))
			 return FALSE;
		break;
	default:
		break;
	}
	return TRUE;
}