diff options
Diffstat (limited to 'eBones/kdb/krb_dbm.c')
| -rw-r--r-- | eBones/kdb/krb_dbm.c | 741 |
1 files changed, 741 insertions, 0 deletions
diff --git a/eBones/kdb/krb_dbm.c b/eBones/kdb/krb_dbm.c new file mode 100644 index 0000000..754dd68 --- /dev/null +++ b/eBones/kdb/krb_dbm.c @@ -0,0 +1,741 @@ +/* + * Copyright 1988 by the Massachusetts Institute of Technology. + * For copying and distribution information, please see the file + * <Copyright.MIT>. + * + * from: krb_dbm.c,v 4.9 89/04/18 16:15:13 wesommer Exp $ + * $Id: krb_dbm.c,v 1.2 1994/07/19 19:23:36 g89r4222 Exp $ + */ + +#ifndef lint +static char rcsid[] = +"$Id: krb_dbm.c,v 1.2 1994/07/19 19:23:36 g89r4222 Exp $"; +#endif lint + +#if defined(__FreeBSD__) +#define NDBM +#endif + +#include <stdio.h> +#include <sys/types.h> +#include <netinet/in.h> +#include <sys/uio.h> +#include <sys/time.h> +#include <sys/stat.h> +#include <sys/resource.h> +#include <sys/errno.h> +#include <strings.h> +#include <des.h> +#include <sys/file.h> +#ifdef NDBM +#include <ndbm.h> +#else /*NDBM*/ +#include <dbm.h> +#endif /*NDBM*/ +/* before krb_db.h */ +#include <krb.h> +#include <krb_db.h> + +#define KERB_DB_MAX_RETRY 5 + +#ifdef DEBUG +extern int debug; +extern long kerb_debug; +extern char *progname; +#endif +extern char *malloc(); +extern int errno; + +static init = 0; +static char default_db_name[] = DBM_FILE; +static char *current_db_name = default_db_name; +static void encode_princ_key(), decode_princ_key(); +static void encode_princ_contents(), decode_princ_contents(); +static void kerb_dbl_fini(); +static int kerb_dbl_lock(); +static void kerb_dbl_unlock(); + +static struct timeval timestamp;/* current time of request */ +static int non_blocking = 0; + +/* + * This module contains all of the code which directly interfaces to + * the underlying representation of the Kerberos database; this + * implementation uses a DBM or NDBM indexed "file" (actually + * implemented as two separate files) to store the relations, plus a + * third file as a semaphore to allow the database to be replaced out + * from underneath the KDC server. + */ + +/* + * Locking: + * + * There are two distinct locking protocols used. One is designed to + * lock against processes (the admin_server, for one) which make + * incremental changes to the database; the other is designed to lock + * against utilities (kdb_util, kpropd) which replace the entire + * database in one fell swoop. + * + * The first locking protocol is implemented using flock() in the + * krb_dbl_lock() and krb_dbl_unlock routines. + * + * The second locking protocol is necessary because DBM "files" are + * actually implemented as two separate files, and it is impossible to + * atomically rename two files simultaneously. It assumes that the + * database is replaced only very infrequently in comparison to the time + * needed to do a database read operation. + * + * A third file is used as a "version" semaphore; the modification + * time of this file is the "version number" of the database. + * At the start of a read operation, the reader checks the version + * number; at the end of the read operation, it checks again. If the + * version number changed, or if the semaphore was nonexistant at + * either time, the reader sleeps for a second to let things + * stabilize, and then tries again; if it does not succeed after + * KERB_DB_MAX_RETRY attempts, it gives up. + * + * On update, the semaphore file is deleted (if it exists) before any + * update takes place; at the end of the update, it is replaced, with + * a version number strictly greater than the version number which + * existed at the start of the update. + * + * If the system crashes in the middle of an update, the semaphore + * file is not automatically created on reboot; this is a feature, not + * a bug, since the database may be inconsistant. Note that the + * absence of a semaphore file does not prevent another _update_ from + * taking place later. Database replacements take place automatically + * only on slave servers; a crash in the middle of an update will be + * fixed by the next slave propagation. A crash in the middle of an + * update on the master would be somewhat more serious, but this would + * likely be noticed by an administrator, who could fix the problem and + * retry the operation. + */ + +/* Macros to convert ndbm names to dbm names. + * Note that dbm_nextkey() cannot be simply converted using a macro, since + * it is invoked giving the database, and nextkey() needs the previous key. + * + * Instead, all routines call "dbm_next" instead. + */ + +#ifndef NDBM +typedef char DBM; + +#define dbm_open(file, flags, mode) ((dbminit(file) == 0)?"":((char *)0)) +#define dbm_fetch(db, key) fetch(key) +#define dbm_store(db, key, content, flag) store(key, content) +#define dbm_firstkey(db) firstkey() +#define dbm_next(db,key) nextkey(key) +#define dbm_close(db) dbmclose() +#else +#define dbm_next(db,key) dbm_nextkey(db) +#endif + +/* + * Utility routine: generate name of database file. + */ + +static char *gen_dbsuffix(db_name, sfx) + char *db_name; + char *sfx; +{ + char *dbsuffix; + + if (sfx == NULL) + sfx = ".ok"; + + dbsuffix = malloc (strlen(db_name) + strlen(sfx) + 1); + strcpy(dbsuffix, db_name); + strcat(dbsuffix, sfx); + return dbsuffix; +} + +/* + * initialization for data base routines. + */ + +kerb_db_init() +{ + init = 1; + return (0); +} + +/* + * gracefully shut down database--must be called by ANY program that does + * a kerb_db_init + */ + +kerb_db_fini() +{ +} + +/* + * Set the "name" of the current database to some alternate value. + * + * Passing a null pointer as "name" will set back to the default. + * If the alternate database doesn't exist, nothing is changed. + */ + +kerb_db_set_name(name) + char *name; +{ + DBM *db; + + if (name == NULL) + name = default_db_name; + db = dbm_open(name, 0, 0); + if (db == NULL) + return errno; + dbm_close(db); + kerb_dbl_fini(); + current_db_name = name; + return 0; +} + +/* + * Return the last modification time of the database. + */ + +long kerb_get_db_age() +{ + struct stat st; + char *okname; + long age; + + okname = gen_dbsuffix(current_db_name, ".ok"); + + if (stat (okname, &st) < 0) + age = 0; + else + age = st.st_mtime; + + free (okname); + return age; +} + +/* + * Remove the semaphore file; indicates that database is currently + * under renovation. + * + * This is only for use when moving the database out from underneath + * the server (for example, during slave updates). + */ + +static long kerb_start_update(db_name) + char *db_name; +{ + char *okname = gen_dbsuffix(db_name, ".ok"); + long age = kerb_get_db_age(); + + if (unlink(okname) < 0 + && errno != ENOENT) { + age = -1; + } + free (okname); + return age; +} + +static long kerb_end_update(db_name, age) + char *db_name; + long age; +{ + int fd; + int retval = 0; + char *new_okname = gen_dbsuffix(db_name, ".ok#"); + char *okname = gen_dbsuffix(db_name, ".ok"); + + fd = open (new_okname, O_CREAT|O_RDWR|O_TRUNC, 0600); + if (fd < 0) + retval = errno; + else { + struct stat st; + struct timeval tv[2]; + /* make sure that semaphore is "after" previous value. */ + if (fstat (fd, &st) == 0 + && st.st_mtime <= age) { + tv[0].tv_sec = st.st_atime; + tv[0].tv_usec = 0; + tv[1].tv_sec = age; + tv[1].tv_usec = 0; + /* set times.. */ + utimes (new_okname, tv); + fsync(fd); + } + close(fd); + if (rename (new_okname, okname) < 0) + retval = errno; + } + + free (new_okname); + free (okname); + + return retval; +} + +static long kerb_start_read() +{ + return kerb_get_db_age(); +} + +static long kerb_end_read(age) + u_long age; +{ + if (kerb_get_db_age() != age || age == -1) { + return -1; + } + return 0; +} + +/* + * Create the database, assuming it's not there. + */ + +kerb_db_create(db_name) + char *db_name; +{ + char *okname = gen_dbsuffix(db_name, ".ok"); + int fd; + register int ret = 0; +#ifdef NDBM + DBM *db; + + db = dbm_open(db_name, O_RDWR|O_CREAT|O_EXCL, 0600); + if (db == NULL) + ret = errno; + else + dbm_close(db); +#else + char *dirname = gen_dbsuffix(db_name, ".dir"); + char *pagname = gen_dbsuffix(db_name, ".pag"); + + fd = open(dirname, O_RDWR|O_CREAT|O_EXCL, 0600); + if (fd < 0) + ret = errno; + else { + close(fd); + fd = open (pagname, O_RDWR|O_CREAT|O_EXCL, 0600); + if (fd < 0) + ret = errno; + else + close(fd); + } + if (dbminit(db_name) < 0) + ret = errno; +#endif + if (ret == 0) { + fd = open (okname, O_CREAT|O_RDWR|O_TRUNC, 0600); + if (fd < 0) + ret = errno; + close(fd); + } + return ret; +} + +/* + * "Atomically" rename the database in a way that locks out read + * access in the middle of the rename. + * + * Not perfect; if we crash in the middle of an update, we don't + * necessarily know to complete the transaction the rename, but... + */ + +kerb_db_rename(from, to) + char *from; + char *to; +{ + char *fromdir = gen_dbsuffix (from, ".dir"); + char *todir = gen_dbsuffix (to, ".dir"); + char *frompag = gen_dbsuffix (from , ".pag"); + char *topag = gen_dbsuffix (to, ".pag"); + char *fromok = gen_dbsuffix(from, ".ok"); + long trans = kerb_start_update(to); + int ok; + + if ((rename (fromdir, todir) == 0) + && (rename (frompag, topag) == 0)) { + (void) unlink (fromok); + ok = 1; + } + + free (fromok); + free (fromdir); + free (todir); + free (frompag); + free (topag); + if (ok) + return kerb_end_update(to, trans); + else + return -1; +} + +/* + * look up a principal in the data base returns number of principals + * found , and whether there were more than requested. + */ + +kerb_db_get_principal(name, inst, principal, max, more) + char *name; /* could have wild card */ + char *inst; /* could have wild card */ + Principal *principal; + unsigned int max; /* max number of name structs to return */ + int *more; /* where there more than 'max' tuples? */ + +{ + int found = 0, code; + extern int errorproc(); + int wildp, wildi; + datum key, contents; + char testname[ANAME_SZ], testinst[INST_SZ]; + u_long trans; + int try; + DBM *db; + + if (!init) + kerb_db_init(); /* initialize database routines */ + + for (try = 0; try < KERB_DB_MAX_RETRY; try++) { + trans = kerb_start_read(); + + if ((code = kerb_dbl_lock(KERB_DBL_SHARED)) != 0) + return -1; + + db = dbm_open(current_db_name, O_RDONLY, 0600); + + *more = 0; + +#ifdef DEBUG + if (kerb_debug & 2) + fprintf(stderr, + "%s: db_get_principal for %s %s max = %d", + progname, name, inst, max); +#endif + + wildp = !strcmp(name, "*"); + wildi = !strcmp(inst, "*"); + + if (!wildi && !wildp) { /* nothing's wild */ + encode_princ_key(&key, name, inst); + contents = dbm_fetch(db, key); + if (contents.dptr == NULL) { + found = 0; + goto done; + } + decode_princ_contents(&contents, principal); +#ifdef DEBUG + if (kerb_debug & 1) { + fprintf(stderr, "\t found %s %s p_n length %d t_n length %d\n", + principal->name, principal->instance, + strlen(principal->name), + strlen(principal->instance)); + } +#endif + found = 1; + goto done; + } + /* process wild cards by looping through entire database */ + + for (key = dbm_firstkey(db); key.dptr != NULL; + key = dbm_next(db, key)) { + decode_princ_key(&key, testname, testinst); + if ((wildp || !strcmp(testname, name)) && + (wildi || !strcmp(testinst, inst))) { /* have a match */ + if (found >= max) { + *more = 1; + goto done; + } else { + found++; + contents = dbm_fetch(db, key); + decode_princ_contents(&contents, principal); +#ifdef DEBUG + if (kerb_debug & 1) { + fprintf(stderr, + "\tfound %s %s p_n length %d t_n length %d\n", + principal->name, principal->instance, + strlen(principal->name), + strlen(principal->instance)); + } +#endif + principal++; /* point to next */ + } + } + } + + done: + kerb_dbl_unlock(); /* unlock read lock */ + dbm_close(db); + if (kerb_end_read(trans) == 0) + break; + found = -1; + if (!non_blocking) + sleep(1); + } + return (found); +} + +/* + * Update a name in the data base. Returns number of names + * successfully updated. + */ + +kerb_db_put_principal(principal, max) + Principal *principal; + unsigned int max; /* number of principal structs to + * update */ + +{ + int found = 0, code; + u_long i; + extern int errorproc(); + datum key, contents; + DBM *db; + + gettimeofday(×tamp, NULL); + + if (!init) + kerb_db_init(); + + if ((code = kerb_dbl_lock(KERB_DBL_EXCLUSIVE)) != 0) + return -1; + + db = dbm_open(current_db_name, O_RDWR, 0600); + +#ifdef DEBUG + if (kerb_debug & 2) + fprintf(stderr, "%s: kerb_db_put_principal max = %d", + progname, max); +#endif + + /* for each one, stuff temps, and do replace/append */ + for (i = 0; i < max; i++) { + encode_princ_contents(&contents, principal); + encode_princ_key(&key, principal->name, principal->instance); + dbm_store(db, key, contents, DBM_REPLACE); +#ifdef DEBUG + if (kerb_debug & 1) { + fprintf(stderr, "\n put %s %s\n", + principal->name, principal->instance); + } +#endif + found++; + principal++; /* bump to next struct */ + } + + dbm_close(db); + kerb_dbl_unlock(); /* unlock database */ + return (found); +} + +static void +encode_princ_key(key, name, instance) + datum *key; + char *name, *instance; +{ + static char keystring[ANAME_SZ + INST_SZ]; + + bzero(keystring, ANAME_SZ + INST_SZ); + strncpy(keystring, name, ANAME_SZ); + strncpy(&keystring[ANAME_SZ], instance, INST_SZ); + key->dptr = keystring; + key->dsize = ANAME_SZ + INST_SZ; +} + +static void +decode_princ_key(key, name, instance) + datum *key; + char *name, *instance; +{ + strncpy(name, key->dptr, ANAME_SZ); + strncpy(instance, key->dptr + ANAME_SZ, INST_SZ); + name[ANAME_SZ - 1] = '\0'; + instance[INST_SZ - 1] = '\0'; +} + +static void +encode_princ_contents(contents, principal) + datum *contents; + Principal *principal; +{ + contents->dsize = sizeof(*principal); + contents->dptr = (char *) principal; +} + +static void +decode_princ_contents(contents, principal) + datum *contents; + Principal *principal; +{ + bcopy(contents->dptr, (char *) principal, sizeof(*principal)); +} + +kerb_db_get_stat(s) + DB_stat *s; +{ + gettimeofday(×tamp, NULL); + + + s->cpu = 0; + s->elapsed = 0; + s->dio = 0; + s->pfault = 0; + s->t_stamp = timestamp.tv_sec; + s->n_retrieve = 0; + s->n_replace = 0; + s->n_append = 0; + s->n_get_stat = 0; + s->n_put_stat = 0; + /* update local copy too */ +} + +kerb_db_put_stat(s) + DB_stat *s; +{ +} + +delta_stat(a, b, c) + DB_stat *a, *b, *c; +{ + /* c = a - b then b = a for the next time */ + + c->cpu = a->cpu - b->cpu; + c->elapsed = a->elapsed - b->elapsed; + c->dio = a->dio - b->dio; + c->pfault = a->pfault - b->pfault; + c->t_stamp = a->t_stamp - b->t_stamp; + c->n_retrieve = a->n_retrieve - b->n_retrieve; + c->n_replace = a->n_replace - b->n_replace; + c->n_append = a->n_append - b->n_append; + c->n_get_stat = a->n_get_stat - b->n_get_stat; + c->n_put_stat = a->n_put_stat - b->n_put_stat; + + bcopy(a, b, sizeof(DB_stat)); + return; +} + +/* + * look up a dba in the data base returns number of dbas found , and + * whether there were more than requested. + */ + +kerb_db_get_dba(dba_name, dba_inst, dba, max, more) + char *dba_name; /* could have wild card */ + char *dba_inst; /* could have wild card */ + Dba *dba; + unsigned int max; /* max number of name structs to return */ + int *more; /* where there more than 'max' tuples? */ + +{ + *more = 0; + return (0); +} + +kerb_db_iterate (func, arg) + int (*func)(); + char *arg; /* void *, really */ +{ + datum key, contents; + Principal *principal; + int code; + DBM *db; + + kerb_db_init(); /* initialize and open the database */ + if ((code = kerb_dbl_lock(KERB_DBL_SHARED)) != 0) + return code; + + db = dbm_open(current_db_name, O_RDONLY, 0600); + + for (key = dbm_firstkey (db); key.dptr != NULL; key = dbm_next(db, key)) { + contents = dbm_fetch (db, key); + /* XXX may not be properly aligned */ + principal = (Principal *) contents.dptr; + if ((code = (*func)(arg, principal)) != 0) + return code; + } + dbm_close(db); + kerb_dbl_unlock(); + return 0; +} + +static int dblfd = -1; +static int mylock = 0; +static int inited = 0; + +static kerb_dbl_init() +{ + if (!inited) { + char *filename = gen_dbsuffix (current_db_name, ".ok"); + if ((dblfd = open(filename, 0)) < 0) { + fprintf(stderr, "kerb_dbl_init: couldn't open %s\n", filename); + fflush(stderr); + perror("open"); + exit(1); + } + free(filename); + inited++; + } + return (0); +} + +static void kerb_dbl_fini() +{ + close(dblfd); + dblfd = -1; + inited = 0; + mylock = 0; +} + +static int kerb_dbl_lock(mode) + int mode; +{ + int flock_mode; + + if (!inited) + kerb_dbl_init(); + if (mylock) { /* Detect lock call when lock already + * locked */ + fprintf(stderr, "Kerberos locking error (mylock)\n"); + fflush(stderr); + exit(1); + } + switch (mode) { + case KERB_DBL_EXCLUSIVE: + flock_mode = LOCK_EX; + break; + case KERB_DBL_SHARED: + flock_mode = LOCK_SH; + break; + default: + fprintf(stderr, "invalid lock mode %d\n", mode); + abort(); + } + if (non_blocking) + flock_mode |= LOCK_NB; + + if (flock(dblfd, flock_mode) < 0) + return errno; + mylock++; + return 0; +} + +static void kerb_dbl_unlock() +{ + if (!mylock) { /* lock already unlocked */ + fprintf(stderr, "Kerberos database lock not locked when unlocking.\n"); + fflush(stderr); + exit(1); + } + if (flock(dblfd, LOCK_UN) < 0) { + fprintf(stderr, "Kerberos database lock error. (unlocking)\n"); + fflush(stderr); + perror("flock"); + exit(1); + } + mylock = 0; +} + +int kerb_db_set_lockmode(mode) + int mode; +{ + int old = non_blocking; + non_blocking = mode; + return old; +} |
