diff options
Diffstat (limited to 'crypto/kerberosIV/lib/kdb/krb_dbm.c')
| -rw-r--r-- | crypto/kerberosIV/lib/kdb/krb_dbm.c | 823 |
1 files changed, 823 insertions, 0 deletions
diff --git a/crypto/kerberosIV/lib/kdb/krb_dbm.c b/crypto/kerberosIV/lib/kdb/krb_dbm.c new file mode 100644 index 0000000..963656a --- /dev/null +++ b/crypto/kerberosIV/lib/kdb/krb_dbm.c @@ -0,0 +1,823 @@ +/* + Copyright (C) 1989 by the Massachusetts Institute of Technology + + Export of this software from the United States of America is assumed + to require a specific license from the United States Government. + It is the responsibility of any person or organization contemplating + export to obtain such a license before exporting. + +WITHIN THAT CONSTRAINT, permission to use, copy, modify, and +distribute this software and its documentation for any purpose and +without fee is hereby granted, provided that the above copyright +notice appear in all copies and that both that copyright notice and +this permission notice appear in supporting documentation, and that +the name of M.I.T. not be used in advertising or publicity pertaining +to distribution of the software without specific, written prior +permission. M.I.T. makes no representations about the suitability of +this software for any purpose. It is provided "as is" without express +or implied warranty. + + */ + +#include "kdb_locl.h" + +RCSID("$Id: krb_dbm.c,v 1.27 1997/05/02 14:29:09 assar Exp $"); + +#include <xdbm.h> + +#define KERB_DB_MAX_RETRY 5 + +#ifdef DEBUG +extern int debug; +extern long kerb_debug; +extern char *progname; +#endif + +static int init = 0; +static char default_db_name[] = DBM_FILE; +static char *current_db_name = default_db_name; + +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. + */ + + +/* + * Utility routine: generate name of database file. + */ + +static char *gen_dbsuffix (char *db_name, char *sfx); + +static char * +gen_dbsuffix(char *db_name, char *sfx) +{ + char *dbsuffix; + + if (sfx == NULL) + sfx = ".ok"; + + asprintf (&dbsuffix, "%s%s", db_name, sfx); + return dbsuffix; +} + +static void +decode_princ_key (datum *key, char *name, char *instance); + +static void +decode_princ_key(datum *key, char *name, char *instance) +{ + strncpy(name, key->dptr, ANAME_SZ); + strncpy(instance, (char *)key->dptr + ANAME_SZ, INST_SZ); + name[ANAME_SZ - 1] = '\0'; + instance[INST_SZ - 1] = '\0'; +} + +static void +encode_princ_contents (datum *contents, Principal *principal); + +static void +encode_princ_contents(datum *contents, Principal *principal) +{ + contents->dsize = sizeof(*principal); + contents->dptr = (char *) principal; +} + +static void +decode_princ_contents (datum *contents, Principal *principal) +{ + memcpy(principal, contents->dptr, sizeof(*principal)); +} + +static void +encode_princ_key (datum *key, char *name, char *instance) +{ + static char keystring[ANAME_SZ + INST_SZ]; + + memset(keystring, 0, 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 int dblfd = -1; /* db LOCK fd */ +static int mylock = 0; +static int inited = 0; + +static int +kerb_dbl_init (void); + +static int +kerb_dbl_init() +{ + if (!inited) { + char *filename = gen_dbsuffix (current_db_name, ".ok"); + if ((dblfd = open(filename, O_RDWR)) < 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 (void); + +static void +kerb_dbl_fini() +{ + close(dblfd); + dblfd = -1; + inited = 0; + mylock = 0; +} + +static int +kerb_dbl_lock (int mode); + +static int +kerb_dbl_lock(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 = K_LOCK_EX; + break; + case KERB_DBL_SHARED: + flock_mode = K_LOCK_SH; + break; + default: + fprintf(stderr, "invalid lock mode %d\n", mode); + abort(); + } + if (non_blocking) + flock_mode |= K_LOCK_NB; + + if (k_flock(dblfd, flock_mode) < 0) + return errno; + mylock++; + return 0; +} + +static void kerb_dbl_unlock (void); + +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 (k_flock(dblfd, K_LOCK_UN) < 0) { + fprintf(stderr, "Kerberos database lock error. (unlocking)\n"); + fflush(stderr); + perror("k_flock"); + exit(1); + } + mylock = 0; +} + +int +kerb_db_set_lockmode (int mode); + +int +kerb_db_set_lockmode(int mode) +{ + int old = non_blocking; + non_blocking = mode; + return old; +} + +/* + * initialization for data base routines. + */ + +int +kerb_db_init (void); + +int +kerb_db_init() +{ + init = 1; + return (0); +} + +/* + * gracefully shut down database--must be called by ANY program that does + * a kerb_db_init + */ + +void +kerb_db_fini (void); + +void +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. + */ + +int +kerb_db_set_name (char *name); + +int +kerb_db_set_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. + */ + +time_t +kerb_get_db_age (void); + +time_t +kerb_get_db_age() +{ + struct stat st; + char *okname; + time_t 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 time_t +kerb_start_update (char *db_name); + +static time_t +kerb_start_update(char *db_name) +{ + char *okname = gen_dbsuffix(db_name, ".ok"); + time_t age = kerb_get_db_age(); + + if (unlink(okname) < 0 + && errno != ENOENT) { + age = -1; + } + free (okname); + return age; +} + +static int +kerb_end_update (char *db_name, time_t age); + +static int +kerb_end_update(char *db_name, time_t 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 utimbuf tv; + /* make sure that semaphore is "after" previous value. */ + if (fstat (fd, &st) == 0 + && st.st_mtime <= age) { + tv.actime = st.st_atime; + tv.modtime = age; + /* set times.. */ + utime (new_okname, &tv); + fsync(fd); + } + close(fd); + if (rename (new_okname, okname) < 0) + retval = errno; + } + + free (new_okname); + free (okname); + + return retval; +} + +static time_t +kerb_start_read (void); + +static time_t +kerb_start_read() +{ + return kerb_get_db_age(); +} + +static int kerb_end_read (time_t age); + +static int +kerb_end_read(time_t age) +{ + if (kerb_get_db_age() != age || age == -1) { + return -1; + } + return 0; +} + +/* + * Create the database, assuming it's not there. + */ +int +kerb_db_create(char *db_name) +{ + char *okname = gen_dbsuffix(db_name, ".ok"); + int fd; + 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... + */ + +int +kerb_db_rename(char *from, char *to) +{ +#ifdef HAVE_NEW_DB + char *fromdb = gen_dbsuffix (from, ".db"); + char *todb = gen_dbsuffix (to, ".db"); +#else + char *fromdir = gen_dbsuffix (from, ".dir"); + char *todir = gen_dbsuffix (to, ".dir"); + char *frompag = gen_dbsuffix (from , ".pag"); + char *topag = gen_dbsuffix (to, ".pag"); +#endif + char *fromok = gen_dbsuffix(from, ".ok"); + long trans = kerb_start_update(to); + int ok = 0; + +#ifdef HAVE_NEW_DB + if (rename (fromdb, todb) == 0) { + unlink (fromok); + ok = 1; + } + free (fromdb); + free (todb); +#else + if ((rename (fromdir, todir) == 0) + && (rename (frompag, topag) == 0)) { + unlink (fromok); + ok = 1; + } + free (fromdir); + free (todir); + free (frompag); + free (topag); +#endif + free (fromok); + if (ok) + return kerb_end_update(to, trans); + else + return -1; +} + +int +kerb_db_delete_principal (char *name, char *inst) +{ + DBM *db; + int try; + int done = 0; + int code; + datum key; + + if(!init) + kerb_db_init(); + + for(try = 0; try < KERB_DB_MAX_RETRY; try++){ + if((code = kerb_dbl_lock(KERB_DBL_SHARED)) != 0) + return -1; + + db = dbm_open(current_db_name, O_RDWR, 0600); + if(db == NULL) + return -1; + encode_princ_key(&key, name, inst); + if(dbm_delete(db, key) == 0) + done = 1; + + dbm_close(db); + kerb_dbl_unlock(); + if(done) + break; + if(!non_blocking) + sleep(1); + } + if(!done) + return -1; + return 0; +} + + +/* + * look up a principal in the data base returns number of principals + * found , and whether there were more than requested. + */ + +int +kerb_db_get_principal (char *name, char *inst, Principal *principal, + unsigned int max, int *more) +{ + int found = 0, code; + 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); +} + +/* Use long * rather than DBM * so that the database structure is private */ + +long * +kerb_db_begin_update(void) +{ + int code; + + gettimeofday(×tamp, NULL); + + if (!init) + kerb_db_init(); + + if ((code = kerb_dbl_lock(KERB_DBL_EXCLUSIVE)) != 0) + return 0; + + return (long *) dbm_open(current_db_name, O_RDWR, 0600); +} + +void +kerb_db_end_update(long *db) +{ + dbm_close((DBM *)db); + kerb_dbl_unlock(); /* unlock database */ +} + +int +kerb_db_update(long *db, Principal *principal, unsigned int max) +{ + int found = 0; + u_long i; + datum key, contents; + +#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((DBM *)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 */ + } + return found; +} + +/* + * Update a name in the data base. Returns number of names + * successfully updated. + */ + +int +kerb_db_put_principal (Principal *principal, unsigned int max); + +int +kerb_db_put_principal(Principal *principal, + unsigned max) + +{ + int found; + long *db; + + db = kerb_db_begin_update(); + if (db == 0) + return -1; + + found = kerb_db_update(db, principal, max); + + kerb_db_end_update(db); + return (found); +} + +void +kerb_db_get_stat (DB_stat *s); + +void +kerb_db_get_stat(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 */ +} + +void +kerb_db_put_stat (DB_stat *s); + +void +kerb_db_put_stat(DB_stat *s) +{ +} + +void +delta_stat (DB_stat *a, DB_stat *b, DB_stat *c); + +void +delta_stat(DB_stat *a, DB_stat *b, DB_stat *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; + + memcpy(b, a, sizeof(DB_stat)); + return; +} + +/* + * look up a dba in the data base returns number of dbas found , and + * whether there were more than requested. + */ + +int +kerb_db_get_dba (char *dba_name, char *dba_inst, Dba *dba, unsigned int max, int *more); + +int +kerb_db_get_dba(char *dba_name, char *dba_inst, Dba *dba, + unsigned max, + int *more) + /* could have wild card */ + /* could have wild card */ + /* max number of name structs to return */ + /* where there more than 'max' tuples? */ +{ + *more = 0; + return (0); +} + +int +kerb_db_iterate (k_iter_proc_t func, void *arg) +{ + 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; +} |
