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

 		if ((ch1 && ch2) && !strcmp(ch1, ch2)) {
 			if (ch11 && *ch11 != '\0') {
 				*--ch11 = s1;
 				ch11++;
 			}
 			if (ch22 && *ch22 != '\0') {
 				*--ch22 = s2;
 				ch22++;
 			}
 			ch1 = ch11;
 			ch2 = ch22;
 			if ((ch11 && *ch11 == '\0') || !ch11) {
				/*
				 * count number of slashes remaining in ancestor
				 */
				if (ch2) {
					for (--ch2; ch2 && *ch2!='\0'; ch2++)
						if (*ch2 == '/') level++;
					if (*--ch2 == '/')
						level--;
				}
 				return(level);
			}
 			if ((ch11 && *ch11 != '\0') && ((ch22 && *ch22 == '\0') || !ch22))
 				done = 1;
 		}
 		else {
 			if (ch11 && *ch11 != '\0')
 				*--ch11 = s1;
 			if (ch22 && *ch22 != '\0')
 				*--ch22 = s2;
 			done = 1;
 		}
 	}
	return(level);
}

/*
 * Skip over slashes (/) and go to first character
 */
char *
goto_char(ch)
 	char *ch;
{
 	for (;ch && *ch == '/'; ch++)
 		;
	if (ch)
 		return(ch);
	else
		return(NULL);
}
 
/*
 * Remove an entry from mounted list
 */
mtd_umount(rqstp, transp)
	struct svc_req *rqstp;
	SVCXPRT *transp;
{
	char *path;
	struct mountdlist *ml, *oldml;
	struct hostent *client;
	long pos = -1;

        if ((client = getclientsname(rqstp,transp))== NULL) {
                svcerr_weakauth(transp);
                return;
        }
	path = NULL;
	if (!svc_getargs(transp, xdr_path, &path)) {
		svcerr_decode(transp);
		mtd_abort();
		return;
	}
#ifdef DEBUG
	(void) fprintf(stderr, "umounting %s for %s\n", path, client->h_name);
#endif
	oldml = mountlist;
	for (ml = mountlist; ml != NULL;
	    oldml = ml, ml = ml->ml_nxt) {
		if (strcmp(ml->ml_path, path) == 0 &&
		    strcmp(ml->ml_name, client->h_name) == 0) {
			if (ml == mountlist)
				mountlist = ml->ml_nxt;
			else
				oldml->ml_nxt = ml->ml_nxt;
#ifdef DEBUG
			(void) fprintf(stderr, "freeing %s\n", path);
#endif
			pos = ml->ml_pos;
			free(ml->ml_path);
			free(ml->ml_name);
			free((char *)ml);
			break;
		    }
	}
	if (!svc_sendreply(transp,xdr_void, NULL)) {
		syslog(LOG_ERR, "couldn't reply to UMOUNT rpc call");
		mtd_abort();
	} else {
		gettimeofday(&now, &tz);
                if ((now.tv_sec - rmtab_written.tv_sec) > rmtab_sync) {
                        dumptofile();
                        rmtab_written = now;
                }
                else if (pos >= 0) {
                        rmtab_delete(pos);
                }
	}
	svc_freeargs(transp, xdr_path, &path);
}

/*
 * Remove all entries for one machine from mounted list
 */
mtd_umountall(rqstp, transp)
	struct svc_req *rqstp;
	SVCXPRT *transp;
{
	char *machine;
	struct mountdlist *ml, *oldml;

	if (!svc_getargs(transp, xdr_void, NULL)) {
		svcerr_decode(transp);
		return;
	}
	/*
	 * We assume that this call is asynchronous and made via the 
	 * portmapper callit routine.  Therefore return control immediately.
	 * The error causes the portmapper to remain silent, as opposed to
	 * every machine on the net blasting the requester with a response.
	 */
	svcerr_systemerr(transp);
        if (rqstp->rq_cred.oa_flavor == AUTH_UNIX) {
                machine =
                   ((struct authunix_parms *)rqstp->rq_clntcred)->aup_machname;
        }
        else
                return;

	oldml = mountlist;
	for (ml = mountlist; ml != NULL; ml = ml->ml_nxt) {
		if (strncmp(ml->ml_name, machine, sizeof(machine)) == 0) {
#ifdef DEBUG
			(void) fprintf(stderr, "got a hit\n");
#endif
			if (ml == mountlist) {
				mountlist = ml->ml_nxt;
				oldml = mountlist;
			}
			else
				oldml->ml_nxt = ml->ml_nxt;
			rmtab_delete(ml->ml_pos);
			free(ml->ml_path);
			free(ml->ml_name);
			free((char *)ml);
		}
		else
			oldml = ml;
	}
	svc_freeargs(transp, xdr_void, NULL);
}

FILE *f;
/*
 * Save current mount state info so we
 * can attempt to recover in case of a crash.
 */
dumptofile()
{
	static char *t1 = "/etc/zzXXXXXX";
	static char *t2 = "/etc/zzXXXXXX";
	FILE *fp;
	struct mountdlist *ml;
	char *mktemp();
	int mf;
	
	(void) fclose(f);
	(void) strcpy(t2, t1);
	t2 = mktemp(t2);
	if ((mf = creat(t2, 0644)) < 0) {
		syslog(LOG_ERR, "creat: %m, cannot dump mountlist to %s", RMTAB);
		return;
	}
	if ((fp = fdopen(mf, "w")) == NULL) {
		syslog(LOG_ERR, "fdopen: %m, cannot dump mountlist to %s", RMTAB);
		return;
	}
	for (ml = mountlist; ml != NULL; ml = ml->ml_nxt) {
		ml->ml_pos = ftell(fp);
		(void) fprintf(fp, "%s:%s\n", ml->ml_name, ml->ml_path);
	}
	if (rename(t2, RMTAB) < 0) 
		syslog(LOG_ERR, "rename: %m, cannot dump mountlist to %s", RMTAB);
	(void) fclose(fp);

	 f = fopen(RMTAB, "r+");
}

/*
 * send current export list
 */
mtd_export(transp)
	SVCXPRT *transp;
{
	struct exports *ex;

	if (!svc_getargs(transp, xdr_void, NULL)) {
		svcerr_decode(transp);
		mtd_abort();
	} else {
		/*
		 * Send exported request the list of flattened exports
		 * to conform with other os's.  Otherwise, all 
		 * exported directories would not be seen.
		 */
		ex = flatexports;
		if (!svc_sendreply(transp, xdr_exports, &ex)) {
			syslog(LOG_ERR, "couldn't reply to EXPORT rpc call");
			mtd_abort();
		}
	}
}

/*
 * Parse exports file.  If this is the first call or the file exportfile
 * has changed, it is opened and parsed to create an exports list.
 * File should look like:
 *
 * pathname [-r=#] [-o] [name1 name2 ... namen]
 *   or
 * #anything
 *
 * pathname:	name of a mounted local file system
 *		name of a directory of a mounted local filesystem
 * optional options
 *	 -r=#	for entire filesystem, root maps to #
 *	 -o	entire filesystem exported readonly
 * name:	netgroup or host name or a list of whitespace separated
 *			names (optional, no names implies everyone)
 *
 * A '#' anywhere in the line marks a comment to the end of that line
 *
 * NOTE: a non-white character in column 1 indicates a new export
 *	specification.
 */
set_exports()
{
	int bol;	/* begining of line */
	int eof;	/* end of file */
	int opt;	/* beginning of option */
	struct exports *ex, *ex2;
	int newdev();
	char ch;
	char *str;
	char *l;
	char line[MAXLINE];	/* current line */
	struct stat statb;
	FILE *fp;
	int isdev;
	int found;
	int bad_entry=0;  /* true if current entry does not exist or is a duplicate */

	if (stat(exportfile, &statb) < 0) {
#ifdef DEBUG
		(void) fprintf(stderr, "%s: stat failed", pgmname);
		perror("mountd: exportfile");
#endif
		freeex(exports);
		exports = NULL;
		freeex(flatexports);
		flatexports = NULL;
		return;
	}
	if (exportstat.st_mtime == statb.st_mtime) {
		return;
	}
	exportstat = statb;

	if ((fp = fopen(exportfile, "r")) == NULL) {
		syslog(LOG_ERR, "fopen: %m");
		freeex(exports);
		exports = NULL;
		freeex(flatexports);
		flatexports = NULL;
		return;
	}

	dupcache_inval();               /* invalidate the dup req cache */
	freeex(exports);
	exports = NULL;
	freeex(flatexports);
	flatexports = NULL;
	eof = 0;

	l = line;
	*l = '\0';
	while (!eof) {
		switch (*l) {
		case '\0':
		case '\n':
			/*
			 * End of line, read next line and set state vars
			 */
			if (fgets(line, MAXLINE, fp) == NULL) {
				eof = 1;
			} else {
				bol = 1;
				opt = 0;
				l = line;
			}
			break;
		case ' ':
		case '	':
			/*
			 * If this is the continuation of a bad entry, skip the line
			 */
			if (bad_entry) {
				*l = '\0';
				break;
			}
			/*
			 * White space, skip to first non-white
			 */
			while (*l == ' ' || *l == '	') {
				l++;
			}
			bol = 0;
			break;
		case '#':
			/*
			 * Comment, skip to end of line.
			 */
			*l = '\0';
			break;
		case '-':
			/*
			 * option of the form: -option=value or -option
			 */
			if (bol) {
				syslog(LOG_ERR, "Cannot parse '%s'", l);
				*l = '\0';
				break;
			}
			opt = 1;
			l++;
			break;
		default:
			/*
			 * normal character: if col one get dir else name or opt
			 */
			str = l;
			while (*l != ' ' && *l != '	' &&
			     *l != '\0' && *l != '\n') {
				l++;
			}
			ch = *l;
			*l = '\0';
			if (bol) {
				/*
				 * Logic for building export list:
				 *  The list is organized by dev horizontally,
				 *  all entries of the same dev hang off vertically.
				 *  The top dev entry is just the first one read.
				 *
				 *  Try to find an exports list entry with the
				 *  same dev number.  If not found, this entry
				 *  represents a new top entry.  Connect its
				 *  devptr to the front of the exports list.
				 *  If a dev match was found, tack this entry on
				 *  to the "next" pointer of the top entry for this 
				 *  dev.  Always check if this is a duplicate entry.
				 */
#ifdef DEBUG_FULL
				(void) fprintf(stderr, "--- next /etc/exports entry to add is %s ---\n", str);
#endif DEBUG_FULL
				bad_entry = 0;  /* this is a new export entry */
				if (stat(str, &statb) < 0) {
					syslog(LOG_ERR, "stat: %m, Cannot stat %s", str);
					bad_entry = 1;
					break;
				}
				for (ex = exports; ex != NULL; ex = ex->ex_devptr) 
					if (ex->ex_dev == statb.st_dev) break;

				if (ex == NULL) {
					isdev = TRUE;
#ifdef DEBUG_FULL
					(void) fprintf(stderr, "adding new export %s\n", str);
#endif DEBUG_FULL
					newdev(str, statb.st_dev, statb.st_ino, statb.st_gennum);
					ex = exports;
				}
				else {
					found = FALSE;
					for (ex2=ex; ex2 != NULL; ex2 = ex2->ex_next)
						if (ex2->ex_ino == statb.st_ino) {
							syslog(LOG_ERR, "Duplicate directory entry for %s - duplicate ignored", str); 
							found = TRUE;
							bad_entry = 1;
							break;
						}
					if (!found) {
						isdev = FALSE;
						/*
					  	   initialize rootmap to nobody and flags to 0
						*/
#ifdef DEBUG_FULL
						(void) fprintf(stderr, "adding new export %s\n", str);
#endif DEBUG_FULL
						ex->ex_next = newex(str, ex->ex_next, statb.st_dev, statb.st_ino, statb.st_gennum, -2, 0);
					}
					else 
						break;  /* skip rest of entry */
				}
			}
			else {
				if (opt) {
					opt = 0;
					if (isdev) 
						setopt(str, ex);
					else 
						setopt(str, ex->ex_next);
				}
				else {
					if (!isdev) {
#ifdef DEBUG_FULL
						(void) fprintf(stderr, "adding new groups %s to %s\n", str, ex->ex_next->ex_name);
#endif DEBUG_FULL
						ex->ex_next->ex_groups = newgroup(str, ex->ex_next->ex_groups);
					}
					else {
#ifdef DEBUG_FULL
						(void) fprintf(stderr, "adding new groups %s to %s\n", str, ex->ex_name);
#endif DEBUG_FULL
						ex->ex_groups = newgroup(str, ex->ex_groups);
					}
				}
			}
			*l = ch;
			bol = 0;
			break;
		}
	}
	(void) fclose(fp);
#ifdef DEBUG
	(void) fprintf(stderr, "*** export list final results ***\n");
	print_exports(exports);
#endif DEBUG

	/*
	 * Update the kernel's exportfsdata list so that it is in sync with
	 * the exports file and the mountd's list.
	 */

	update_exportfsdata();
	flatten_exports();
#ifdef DEBUG_FULL
	(void) fprintf(stderr, "*** export list final results flattened ***\n");
	print_exports(flatexports);
#endif DEBUG_FULL
	return;
}

/*
 * Make exportfs calls necessary to update kernel's view of exports.
 */
update_exportfsdata()
{
	struct exports *ex, *ex2, *k_ex=NULL, *k_ptr;
	struct exportfsdata kbuf;
	u_int cookie=0;

	/*
	 * Build a list equivalent to kernel's list.
	 */
	for (;;) {
		if ((exportfs (EXPORTFS_READ, &cookie, &kbuf)) < 0) {
			if (errno == ENOENT) break;
			syslog(LOG_ERR, "exportfs READ: %m");
			exit (1);
		}
		k_ex = newex(kbuf.e_path, k_ex, kbuf.e_fsid, kbuf.e_gnum, kbuf.e_gen, kbuf.e_rootmap, kbuf.e_flags);
		if (kbuf.e_more == 0) break;
	}
#ifdef DEBUG_FULL 
	(void) fprintf (stderr, "*** Kernel exportfsdata before changes ***\n");
	print_exports(k_ex);
#endif DEBUG_FULL  

	/*
	 * Loop through mountd's export list.  Find matching entry in
	 * local view of kernel's exportfsdata list.  If one is not found,
	 * add this export to kernel's list.  If they are different,
	 * update the kernel's data.  Mark the k_ex entry that has 
	 * been looked at so that we know what hasn't been checked yet.
	 */

	 for (ex=exports; ex!=NULL; ex=ex->ex_devptr) {
		for (ex2=ex; ex2!=NULL; ex2=ex2->ex_next) {

			/*
			   find matching kernel entry
			*/
			for (k_ptr=k_ex; k_ptr!=NULL; k_ptr=k_ptr->ex_next)
				if ((strcmp(k_ptr->ex_name, ex2->ex_name))==0) break;

			/*