diff options
Diffstat (limited to 'mdk-stage1/ppp/pppd/tdb.c')
| -rw-r--r-- | mdk-stage1/ppp/pppd/tdb.c | 1282 |
1 files changed, 0 insertions, 1282 deletions
diff --git a/mdk-stage1/ppp/pppd/tdb.c b/mdk-stage1/ppp/pppd/tdb.c deleted file mode 100644 index 7fd58291e..000000000 --- a/mdk-stage1/ppp/pppd/tdb.c +++ /dev/null @@ -1,1282 +0,0 @@ -/* - * Database functions - * Copyright (C) Andrew Tridgell 1999 - * - * Redistribution and use in source and binary forms are permitted - * provided that the above copyright notice and this paragraph are - * duplicated in all such forms AND provided that this software or - * any derived work is only used as part of the PPP daemon (pppd) - * and related utilities. - * The name of the author may not be used to endorse or promote products - * derived from this software without specific prior written permission. - * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR - * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED - * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. - * - * Note: this software is also available under the Gnu Public License - * version 2 or later. - */ - -#include <stdlib.h> -#include <stdio.h> -#include <fcntl.h> -#include <unistd.h> -#include <string.h> -#include <fcntl.h> -#include <errno.h> -#include <sys/mman.h> -#include <sys/stat.h> -#include "tdb.h" - -#define TDB_VERSION (0x26011967 + 1) -#define TDB_MAGIC (0x26011999U) -#define TDB_FREE_MAGIC (~TDB_MAGIC) -#define TDB_ALIGN 4 -#define MIN_REC_SIZE (2*sizeof(struct list_struct) + TDB_ALIGN) -#define DEFAULT_HASH_SIZE 128 -#define TDB_PAGE_SIZE 0x2000 -#define TDB_LEN_MULTIPLIER 10 -#define FREELIST_TOP (sizeof(struct tdb_header)) - -#define LOCK_SET 1 -#define LOCK_CLEAR 0 - -/* lock offsets */ -#define GLOBAL_LOCK 0 -#define ACTIVE_LOCK 4 -#define LIST_LOCK_BASE 1024 - -#define BUCKET(hash) ((hash) % tdb->header.hash_size) - -#ifndef MAP_FILE -#define MAP_FILE 0 -#endif - -/* the body of the database is made of one list_struct for the free space - plus a separate data list for each hash value */ -struct list_struct { - tdb_len rec_len; /* total byte length of record */ - tdb_off next; /* offset of the next record in the list */ - tdb_len key_len; /* byte length of key */ - tdb_len data_len; /* byte length of data */ - unsigned full_hash; /* the full 32 bit hash of the key */ - unsigned magic; /* try to catch errors */ - /* - the following union is implied - union { - char record[rec_len]; - struct { - char key[key_len]; - char data[data_len]; - } - } - */ -}; - -/* a null data record - useful for error returns */ -static TDB_DATA null_data; - -/* a byte range locking function - return 0 on success - this functions locks/unlocks 1 byte at the specified offset */ -static int tdb_brlock(TDB_CONTEXT *tdb, tdb_off offset, - int set, int rw_type, int lck_type) -{ -#if NOLOCK - return 0; -#else - struct flock fl; - - if (tdb->fd == -1) return 0; /* for in memory tdb */ - - if (tdb->read_only) return -1; - - fl.l_type = set==LOCK_SET?rw_type:F_UNLCK; - fl.l_whence = SEEK_SET; - fl.l_start = offset; - fl.l_len = 1; - fl.l_pid = 0; - - if (fcntl(tdb->fd, lck_type, &fl) != 0) { -#if TDB_DEBUG - if (lck_type == F_SETLKW) { - printf("lock %d failed at %d (%s)\n", - set, offset, strerror(errno)); - } -#endif - tdb->ecode = TDB_ERR_LOCK; - return -1; - } - return 0; -#endif -} - -/* lock a list in the database. list -1 is the alloc list */ -static int tdb_lock(TDB_CONTEXT *tdb, int list) -{ - if (list < -1 || list >= (int)tdb->header.hash_size) { -#if TDB_DEBUG - printf("bad list %d\n", list); -#endif - return -1; - } - if (tdb->locked[list+1] == 0) { - if (tdb_brlock(tdb, LIST_LOCK_BASE + 4*list, LOCK_SET, - F_WRLCK, F_SETLKW) != 0) { - return -1; - } - } - tdb->locked[list+1]++; - return 0; -} - -/* unlock the database. */ -static int tdb_unlock(TDB_CONTEXT *tdb, int list) -{ - if (list < -1 || list >= (int)tdb->header.hash_size) { -#if TDB_DEBUG - printf("bad unlock list %d\n", list); -#endif - return -1; - } - - if (tdb->locked[list+1] == 0) { -#if TDB_DEBUG - printf("not locked %d\n", list); -#endif - tdb->ecode = TDB_ERR_LOCK; - return -1; - } - if (tdb->locked[list+1] == 1) { - if (tdb_brlock(tdb, LIST_LOCK_BASE + 4*list, LOCK_CLEAR, - F_WRLCK, F_SETLKW) != 0) { - return -1; - } - } - tdb->locked[list+1]--; - return 0; -} - -/* the hash algorithm - turn a key into an integer - This is based on the hash agorithm from gdbm */ -static unsigned tdb_hash(TDB_DATA *key) -{ - unsigned value; /* Used to compute the hash value. */ - unsigned i; /* Used to cycle through random values. */ - - /* Set the initial value from the key size. */ - value = 0x238F13AF * key->dsize; - for (i=0; i < key->dsize; i++) { - value = (value + (key->dptr[i] << (i*5 % 24))); - } - - value = (1103515243 * value + 12345); - - return value; -} - -/* find the top of the hash chain for an open database */ -static tdb_off tdb_hash_top(TDB_CONTEXT *tdb, unsigned hash) -{ - tdb_off ret; - hash = BUCKET(hash); - ret = FREELIST_TOP + (hash+1)*sizeof(tdb_off); - return ret; -} - - -/* check for an out of bounds access - if it is out of bounds then - see if the database has been expanded by someone else and expand - if necessary */ -static int tdb_oob(TDB_CONTEXT *tdb, tdb_off offset) -{ - struct stat st; - if ((offset <= tdb->map_size) || (tdb->fd == -1)) return 0; - - fstat(tdb->fd, &st); - if (st.st_size <= (ssize_t)offset) { - tdb->ecode = TDB_ERR_IO; - return -1; - } - -#if HAVE_MMAP - if (tdb->map_ptr) { - munmap(tdb->map_ptr, tdb->map_size); - tdb->map_ptr = NULL; - } -#endif - - tdb->map_size = st.st_size; -#if HAVE_MMAP - tdb->map_ptr = (void *)mmap(NULL, tdb->map_size, - tdb->read_only?PROT_READ:PROT_READ|PROT_WRITE, - MAP_SHARED | MAP_FILE, tdb->fd, 0); -#endif - return 0; -} - - -/* write a lump of data at a specified offset */ -static int tdb_write(TDB_CONTEXT *tdb, tdb_off offset, const char *buf, tdb_len len) -{ - if (tdb_oob(tdb, offset + len) != 0) { - /* oops - trying to write beyond the end of the database! */ - return -1; - } - - if (tdb->map_ptr) { - memcpy(offset + (char *)tdb->map_ptr, buf, len); - } else { - if (lseek(tdb->fd, offset, SEEK_SET) != offset || - write(tdb->fd, buf, len) != (ssize_t)len) { - tdb->ecode = TDB_ERR_IO; - return -1; - } - } - return 0; -} - -/* read a lump of data at a specified offset */ -static int tdb_read(TDB_CONTEXT *tdb, tdb_off offset, char *buf, tdb_len len) -{ - if (tdb_oob(tdb, offset + len) != 0) { - /* oops - trying to read beyond the end of the database! */ - return -1; - } - - if (tdb->map_ptr) { - memcpy(buf, offset + (char *)tdb->map_ptr, len); - } else { - if (lseek(tdb->fd, offset, SEEK_SET) != offset || - read(tdb->fd, buf, len) != (ssize_t)len) { - tdb->ecode = TDB_ERR_IO; - return -1; - } - } - return 0; -} - - -/* read a lump of data, allocating the space for it */ -static char *tdb_alloc_read(TDB_CONTEXT *tdb, tdb_off offset, tdb_len len) -{ - char *buf; - - buf = (char *)malloc(len); - - if (!buf) { - tdb->ecode = TDB_ERR_OOM; - return NULL; - } - - if (tdb_read(tdb, offset, buf, len) == -1) { - free(buf); - return NULL; - } - - return buf; -} - -/* convenience routine for writing a record */ -static int rec_write(TDB_CONTEXT *tdb, tdb_off offset, struct list_struct *rec) -{ - return tdb_write(tdb, offset, (char *)rec, sizeof(*rec)); -} - -/* convenience routine for writing a tdb_off */ -static int ofs_write(TDB_CONTEXT *tdb, tdb_off offset, tdb_off *d) -{ - return tdb_write(tdb, offset, (char *)d, sizeof(*d)); -} - -/* read a tdb_off from the store */ -static int ofs_read(TDB_CONTEXT *tdb, tdb_off offset, tdb_off *d) -{ - return tdb_read(tdb, offset, (char *)d, sizeof(*d)); -} - -/* read a record and check for simple errors */ -static int rec_read(TDB_CONTEXT *tdb, tdb_off offset, struct list_struct *rec) -{ - if (tdb_read(tdb, offset, (char *)rec, sizeof(*rec)) == -1) return -1; - if (rec->magic != TDB_MAGIC) { -#if TDB_DEBUG - printf("bad magic 0x%08x at offset %d\n", - rec->magic, offset); -#endif - tdb->ecode = TDB_ERR_CORRUPT; - return -1; - } - if (tdb_oob(tdb, rec->next) != 0) { - return -1; - } - return 0; -} - -/* expand the database at least length bytes by expanding the - underlying file and doing the mmap again if necessary */ -static int tdb_expand(TDB_CONTEXT *tdb, tdb_off length) -{ - struct list_struct rec; - tdb_off offset, ptr; - char b = 0; - - tdb_lock(tdb,-1); - - /* make sure we know about any previous expansions by another - process */ - tdb_oob(tdb,tdb->map_size + 1); - - /* always make room for at least 10 more records */ - length *= TDB_LEN_MULTIPLIER; - - /* and round the database up to a multiple of TDB_PAGE_SIZE */ - length = ((tdb->map_size + length + TDB_PAGE_SIZE) & ~(TDB_PAGE_SIZE - 1)) - tdb->map_size; - - /* expand the file itself */ - if (tdb->fd != -1) { - lseek(tdb->fd, tdb->map_size + length - 1, SEEK_SET); - if (write(tdb->fd, &b, 1) != 1) goto fail; - } - - /* form a new freelist record */ - offset = FREELIST_TOP; - rec.rec_len = length - sizeof(rec); - rec.magic = TDB_FREE_MAGIC; - if (ofs_read(tdb, offset, &rec.next) == -1) { - goto fail; - } - -#if HAVE_MMAP - if (tdb->fd != -1 && tdb->map_ptr) { - munmap(tdb->map_ptr, tdb->map_size); - tdb->map_ptr = NULL; - } -#endif - - tdb->map_size += length; - - if (tdb->fd == -1) { - tdb->map_ptr = realloc(tdb->map_ptr, tdb->map_size); - } - - /* write it out */ - if (rec_write(tdb, tdb->map_size - length, &rec) == -1) { - goto fail; - } - - /* link it into the free list */ - ptr = tdb->map_size - length; - if (ofs_write(tdb, offset, &ptr) == -1) goto fail; - -#if HAVE_MMAP - if (tdb->fd != -1) { - tdb->map_ptr = (void *)mmap(NULL, tdb->map_size, - PROT_READ|PROT_WRITE, - MAP_SHARED | MAP_FILE, tdb->fd, 0); - } -#endif - - tdb_unlock(tdb, -1); - return 0; - - fail: - tdb_unlock(tdb,-1); - return -1; -} - -/* allocate some space from the free list. The offset returned points - to a unconnected list_struct within the database with room for at - least length bytes of total data - - 0 is returned if the space could not be allocated - */ -static tdb_off tdb_allocate(TDB_CONTEXT *tdb, tdb_len length) -{ - tdb_off offset, rec_ptr, last_ptr; - struct list_struct rec, lastrec, newrec; - - tdb_lock(tdb, -1); - - again: - last_ptr = 0; - offset = FREELIST_TOP; - - /* read in the freelist top */ - if (ofs_read(tdb, offset, &rec_ptr) == -1) { - goto fail; - } - - /* keep looking until we find a freelist record that is big - enough */ - while (rec_ptr) { - if (tdb_read(tdb, rec_ptr, (char *)&rec, sizeof(rec)) == -1) { - goto fail; - } - - if (rec.magic != TDB_FREE_MAGIC) { -#if TDB_DEBUG - printf("bad magic 0x%08x in free list\n", rec.magic); -#endif - goto fail; - } - - if (rec.rec_len >= length) { - /* found it - now possibly split it up */ - if (rec.rec_len > length + MIN_REC_SIZE) { - length = (length + TDB_ALIGN) & ~(TDB_ALIGN-1); - - newrec.rec_len = rec.rec_len - (sizeof(rec) + length); - newrec.next = rec.next; - newrec.magic = TDB_FREE_MAGIC; - - rec.rec_len = length; - rec.next = rec_ptr + sizeof(rec) + rec.rec_len; - - if (rec_write(tdb, rec.next, &newrec) == -1) { - goto fail; - } - - if (rec_write(tdb, rec_ptr, &rec) == -1) { - goto fail; - } - } - - /* remove it from the list */ - if (last_ptr == 0) { - offset = FREELIST_TOP; - - if (ofs_write(tdb, offset, &rec.next) == -1) { - goto fail; - } - } else { - lastrec.next = rec.next; - if (rec_write(tdb, last_ptr, &lastrec) == -1) { - goto fail; - } - } - - /* all done - return the new record offset */ - tdb_unlock(tdb, -1); - return rec_ptr; - } - - /* move to the next record */ - lastrec = rec; - last_ptr = rec_ptr; - rec_ptr = rec.next; - } - - /* we didn't find enough space. See if we can expand the - database and if we can then try again */ - if (tdb_expand(tdb, length + sizeof(rec)) == 0) goto again; - - fail: -#if TDB_DEBUG - printf("tdb_allocate failed for size %u\n", length); -#endif - tdb_unlock(tdb, -1); - return 0; -} - -/* initialise a new database with a specified hash size */ -static int tdb_new_database(TDB_CONTEXT *tdb, int hash_size) -{ - struct tdb_header header; - tdb_off offset; - int i, size = 0; - tdb_off buf[16]; - - /* create the header */ - memset(&header, 0, sizeof(header)); - memcpy(header.magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1); - header.version = TDB_VERSION; - header.hash_size = hash_size; - lseek(tdb->fd, 0, SEEK_SET); - ftruncate(tdb->fd, 0); - - if (tdb->fd != -1 && write(tdb->fd, &header, sizeof(header)) != - sizeof(header)) { - tdb->ecode = TDB_ERR_IO; - return -1; - } else size += sizeof(header); - - /* the freelist and hash pointers */ - offset = 0; - memset(buf, 0, sizeof(buf)); - - for (i=0;(hash_size+1)-i >= 16; i += 16) { - if (tdb->fd != -1 && write(tdb->fd, buf, sizeof(buf)) != - sizeof(buf)) { - tdb->ecode = TDB_ERR_IO; - return -1; - } else size += sizeof(buf); - } - - for (;i<hash_size+1; i++) { - if (tdb->fd != -1 && write(tdb->fd, buf, sizeof(tdb_off)) != - sizeof(tdb_off)) { - tdb->ecode = TDB_ERR_IO; - return -1; - } else size += sizeof(tdb_off); - } - - if (tdb->fd == -1) { - tdb->map_ptr = calloc(size, 1); - tdb->map_size = size; - if (tdb->map_ptr == NULL) { - tdb->ecode = TDB_ERR_IO; - return -1; - } - memcpy(&tdb->header, &header, sizeof(header)); - } - -#if TDB_DEBUG - printf("initialised database of hash_size %u\n", - hash_size); -#endif - return 0; -} - -/* Returns 0 on fail. On success, return offset of record, and fills - in rec */ -static tdb_off tdb_find(TDB_CONTEXT *tdb, TDB_DATA key, unsigned int hash, - struct list_struct *rec) -{ - tdb_off offset, rec_ptr; - - /* find the top of the hash chain */ - offset = tdb_hash_top(tdb, hash); - - /* read in the hash top */ - if (ofs_read(tdb, offset, &rec_ptr) == -1) - return 0; - - /* keep looking until we find the right record */ - while (rec_ptr) { - if (rec_read(tdb, rec_ptr, rec) == -1) - return 0; - - if (hash == rec->full_hash && key.dsize == rec->key_len) { - char *k; - /* a very likely hit - read the key */ - k = tdb_alloc_read(tdb, rec_ptr + sizeof(*rec), - rec->key_len); - - if (!k) - return 0; - - if (memcmp(key.dptr, k, key.dsize) == 0) { - free(k); - return rec_ptr; - } - free(k); - } - - /* move to the next record */ - rec_ptr = rec->next; - } - return 0; -} - -/* - return an error string for the last tdb error -*/ -char *tdb_error(TDB_CONTEXT *tdb) -{ - int i; - static struct { - enum TDB_ERROR ecode; - char *estring; - } emap[] = { - {TDB_SUCCESS, "Success"}, - {TDB_ERR_CORRUPT, "Corrupt database"}, - {TDB_ERR_IO, "IO Error"}, - {TDB_ERR_LOCK, "Locking error"}, - {TDB_ERR_OOM, "Out of memory"}, - {TDB_ERR_EXISTS, "Record exists"}, - {-1, NULL}}; - if (tdb != NULL) { - for (i=0;emap[i].estring;i++) { - if (tdb->ecode == emap[i].ecode) return emap[i].estring; - } - } else { - return "Invalid tdb context"; - } - return "Invalid error code"; -} - - -/* update an entry in place - this only works if the new data size - is <= the old data size and the key exists. - on failure return -1 -*/ -int tdb_update(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf) -{ - unsigned hash; - struct list_struct rec; - tdb_off rec_ptr; - int ret = -1; - - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_update() called with null context\n"); -#endif - return -1; - } - - /* find which hash bucket it is in */ - hash = tdb_hash(&key); - - tdb_lock(tdb, BUCKET(hash)); - rec_ptr = tdb_find(tdb, key, hash, &rec); - - if (!rec_ptr) - goto out; - - /* must be long enough */ - if (rec.rec_len < key.dsize + dbuf.dsize) - goto out; - - if (tdb_write(tdb, rec_ptr + sizeof(rec) + rec.key_len, - dbuf.dptr, dbuf.dsize) == -1) - goto out; - - if (dbuf.dsize != rec.data_len) { - /* update size */ - rec.data_len = dbuf.dsize; - ret = rec_write(tdb, rec_ptr, &rec); - } else - ret = 0; - - out: - tdb_unlock(tdb, BUCKET(hash)); - return ret; -} - -/* find an entry in the database given a key */ -TDB_DATA tdb_fetch(TDB_CONTEXT *tdb, TDB_DATA key) -{ - unsigned hash; - tdb_off rec_ptr; - struct list_struct rec; - TDB_DATA ret = null_data; - - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_fetch() called with null context\n"); -#endif - return null_data; - } - - /* find which hash bucket it is in */ - hash = tdb_hash(&key); - - tdb_lock(tdb, BUCKET(hash)); - rec_ptr = tdb_find(tdb, key, hash, &rec); - - if (rec_ptr) { - ret.dptr = tdb_alloc_read(tdb, - rec_ptr + sizeof(rec) + rec.key_len, - rec.data_len); - ret.dsize = rec.data_len; - } - - tdb_unlock(tdb, BUCKET(hash)); - return ret; -} - -/* check if an entry in the database exists - - note that 1 is returned if the key is found and 0 is returned if not found - this doesn't match the conventions in the rest of this module, but is - compatible with gdbm -*/ -int tdb_exists(TDB_CONTEXT *tdb, TDB_DATA key) -{ - unsigned hash; - tdb_off rec_ptr; - struct list_struct rec; - - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_exists() called with null context\n"); -#endif - return 0; - } - - /* find which hash bucket it is in */ - hash = tdb_hash(&key); - - tdb_lock(tdb, BUCKET(hash)); - rec_ptr = tdb_find(tdb, key, hash, &rec); - tdb_unlock(tdb, BUCKET(hash)); - - return rec_ptr != 0; -} - -/* traverse the entire database - calling fn(tdb, key, data) on each element. - return -1 on error or the record count traversed - if fn is NULL then it is not called - a non-zero return value from fn() indicates that the traversal should stop - */ -int tdb_traverse(TDB_CONTEXT *tdb, int (*fn)(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, void* state), void* state) -{ - int count = 0; - unsigned h; - tdb_off offset, rec_ptr; - struct list_struct rec; - char *data; - TDB_DATA key, dbuf; - - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_traverse() called with null context\n"); -#endif - return -1; - } - - /* loop over all hash chains */ - for (h = 0; h < tdb->header.hash_size; h++) { - tdb_lock(tdb, BUCKET(h)); - - /* read in the hash top */ - offset = tdb_hash_top(tdb, h); - if (ofs_read(tdb, offset, &rec_ptr) == -1) { - goto fail; - } - - /* traverse all records for this hash */ - while (rec_ptr) { - if (rec_read(tdb, rec_ptr, &rec) == -1) { - goto fail; - } - - /* now read the full record */ - data = tdb_alloc_read(tdb, rec_ptr + sizeof(rec), - rec.key_len + rec.data_len); - if (!data) { - goto fail; - } - - key.dptr = data; - key.dsize = rec.key_len; - dbuf.dptr = data + rec.key_len; - dbuf.dsize = rec.data_len; - count++; - - if (fn && fn(tdb, key, dbuf, state) != 0) { - /* they want us to stop traversing */ - free(data); - tdb_unlock(tdb, BUCKET(h)); - return count; - } - - /* a miss - drat */ - free(data); - - /* move to the next record */ - rec_ptr = rec.next; - } - tdb_unlock(tdb, BUCKET(h)); - } - - /* return the number traversed */ - return count; - - fail: - tdb_unlock(tdb, BUCKET(h)); - return -1; -} - - -/* find the first entry in the database and return its key */ -TDB_DATA tdb_firstkey(TDB_CONTEXT *tdb) -{ - tdb_off offset, rec_ptr; - struct list_struct rec; - unsigned hash; - TDB_DATA ret; - - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_firstkey() called with null context\n"); -#endif - return null_data; - } - - /* look for a non-empty hash chain */ - for (hash = 0, rec_ptr = 0; - hash < tdb->header.hash_size; - hash++) { - /* find the top of the hash chain */ - offset = tdb_hash_top(tdb, hash); - - tdb_lock(tdb, BUCKET(hash)); - - /* read in the hash top */ - if (ofs_read(tdb, offset, &rec_ptr) == -1) { - goto fail; - } - - if (rec_ptr) break; - - tdb_unlock(tdb, BUCKET(hash)); - } - - if (rec_ptr == 0) return null_data; - - /* we've found a non-empty chain, now read the record */ - if (rec_read(tdb, rec_ptr, &rec) == -1) { - goto fail; - } - - /* allocate and read the key space */ - ret.dptr = tdb_alloc_read(tdb, rec_ptr + sizeof(rec), rec.key_len); - ret.dsize = rec.key_len; - tdb_unlock(tdb, BUCKET(hash)); - return ret; - - fail: - tdb_unlock(tdb, BUCKET(hash)); - return null_data; -} - -/* find the next entry in the database, returning its key */ -TDB_DATA tdb_nextkey(TDB_CONTEXT *tdb, TDB_DATA key) -{ - unsigned hash, hbucket; - tdb_off rec_ptr, offset; - struct list_struct rec; - TDB_DATA ret; - - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_nextkey() called with null context\n"); -#endif - return null_data; - } - - /* find which hash bucket it is in */ - hash = tdb_hash(&key); - hbucket = BUCKET(hash); - - tdb_lock(tdb, hbucket); - rec_ptr = tdb_find(tdb, key, hash, &rec); - if (rec_ptr) { - /* we want the next record after this one */ - rec_ptr = rec.next; - } - - /* not found or last in hash: look for next non-empty hash chain */ - while (rec_ptr == 0) { - tdb_unlock(tdb, hbucket); - - if (++hbucket >= tdb->header.hash_size - 1) - return null_data; - - offset = tdb_hash_top(tdb, hbucket); - tdb_lock(tdb, hbucket); - /* read in the hash top */ - if (ofs_read(tdb, offset, &rec_ptr) == -1) { - tdb_unlock(tdb, hbucket); - return null_data; - } - } - - /* Read the record. */ - if (rec_read(tdb, rec_ptr, &rec) == -1) { - tdb_unlock(tdb, hbucket); - return null_data; - } - /* allocate and read the key */ - ret.dptr = tdb_alloc_read(tdb, rec_ptr + sizeof(rec), rec.key_len); - ret.dsize = rec.key_len; - tdb_unlock(tdb, hbucket); - - return ret; -} - -/* delete an entry in the database given a key */ -int tdb_delete(TDB_CONTEXT *tdb, TDB_DATA key) -{ - unsigned hash; - tdb_off offset, rec_ptr, last_ptr; - struct list_struct rec, lastrec; - char *data = NULL; - - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_delete() called with null context\n"); -#endif - return -1; - } - - /* find which hash bucket it is in */ - hash = tdb_hash(&key); - - tdb_lock(tdb, BUCKET(hash)); - - /* find the top of the hash chain */ - offset = tdb_hash_top(tdb, hash); - - /* read in the hash top */ - if (ofs_read(tdb, offset, &rec_ptr) == -1) { - goto fail; - } - - last_ptr = 0; - - /* keep looking until we find the right record */ - while (rec_ptr) { - if (rec_read(tdb, rec_ptr, &rec) == -1) { - goto fail; - } - - if (hash == rec.full_hash && key.dsize == rec.key_len) { - /* a very likely hit - read the record and full key */ - data = tdb_alloc_read(tdb, rec_ptr + sizeof(rec), - rec.key_len); - if (!data) { - goto fail; - } - - if (memcmp(key.dptr, data, key.dsize) == 0) { - /* a definite match - delete it */ - if (last_ptr == 0) { - offset = tdb_hash_top(tdb, hash); - if (ofs_write(tdb, offset, &rec.next) == -1) { - goto fail; - } - } else { - lastrec.next = rec.next; - if (rec_write(tdb, last_ptr, &lastrec) == -1) { - goto fail; - } - } - tdb_unlock(tdb, BUCKET(hash)); - tdb_lock(tdb, -1); - /* and recover the space */ - offset = FREELIST_TOP; - if (ofs_read(tdb, offset, &rec.next) == -1) { - goto fail2; - } - rec.magic = TDB_FREE_MAGIC; - if (rec_write(tdb, rec_ptr, &rec) == -1) { - goto fail2; - } - if (ofs_write(tdb, offset, &rec_ptr) == -1) { - goto fail2; - } - - /* yipee - all done */ - free(data); - tdb_unlock(tdb, -1); - return 0; - } - - /* a miss - drat */ - free(data); - data = NULL; - } - - /* move to the next record */ - last_ptr = rec_ptr; - lastrec = rec; - rec_ptr = rec.next; - } - - fail: - if (data) free(data); - tdb_unlock(tdb, BUCKET(hash)); - return -1; - - fail2: - if (data) free(data); - tdb_unlock(tdb, -1); - return -1; -} - - -/* store an element in the database, replacing any existing element - with the same key - - return 0 on success, -1 on failure -*/ -int tdb_store(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, int flag) -{ - struct list_struct rec; - unsigned hash; - tdb_off rec_ptr, offset; - char *p = NULL; - - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_store() called with null context\n"); -#endif - return -1; - } - - /* find which hash bucket it is in */ - hash = tdb_hash(&key); - - /* check for it existing */ - if (flag == TDB_INSERT && tdb_exists(tdb, key)) { - tdb->ecode = TDB_ERR_EXISTS; - return -1; - } - - /* first try in-place update */ - if (flag != TDB_INSERT && tdb_update(tdb, key, dbuf) == 0) { - return 0; - } - - rec_ptr = tdb_allocate(tdb, key.dsize + dbuf.dsize); - if (rec_ptr == 0) { - return -1; - } - - tdb_lock(tdb, BUCKET(hash)); - - /* delete any existing record - if it doesn't exist we don't care */ - if (flag != TDB_INSERT) { - tdb_delete(tdb, key); - } - - /* read the newly created record */ - if (tdb_read(tdb, rec_ptr, (char *)&rec, sizeof(rec)) == -1) { - goto fail; - } - - if (rec.magic != TDB_FREE_MAGIC) goto fail; - - /* find the top of the hash chain */ - offset = tdb_hash_top(tdb, hash); - - /* read in the hash top diretcly into our next pointer */ - if (ofs_read(tdb, offset, &rec.next) == -1) { - goto fail; - } - - rec.key_len = key.dsize; - rec.data_len = dbuf.dsize; - rec.full_hash = hash; - rec.magic = TDB_MAGIC; - - p = (char *)malloc(sizeof(rec) + key.dsize + dbuf.dsize); - if (!p) { - tdb->ecode = TDB_ERR_OOM; - goto fail; - } - - memcpy(p, &rec, sizeof(rec)); - memcpy(p+sizeof(rec), key.dptr, key.dsize); - memcpy(p+sizeof(rec)+key.dsize, dbuf.dptr, dbuf.dsize); - - if (tdb_write(tdb, rec_ptr, p, sizeof(rec)+key.dsize+dbuf.dsize) == -1) - goto fail; - - free(p); - p = NULL; - - /* and point the top of the hash chain at it */ - if (ofs_write(tdb, offset, &rec_ptr) == -1) goto fail; - - tdb_unlock(tdb, BUCKET(hash)); - return 0; - - fail: -#if TDB_DEBUG - printf("store failed for hash 0x%08x in bucket %u\n", hash, BUCKET(hash)); -#endif - if (p) free(p); - tdb_unlock(tdb, BUCKET(hash)); - return -1; -} - - -/* open the database, creating it if necessary - - The open_flags and mode are passed straight to the open call on the database - file. A flags value of O_WRONLY is invalid - - The hash size is advisory, use zero for a default value. - - return is NULL on error -*/ -TDB_CONTEXT *tdb_open(char *name, int hash_size, int tdb_flags, - int open_flags, mode_t mode) -{ - TDB_CONTEXT tdb, *ret; - struct stat st; - - memset(&tdb, 0, sizeof(tdb)); - - tdb.fd = -1; - tdb.name = NULL; - tdb.map_ptr = NULL; - - if ((open_flags & O_ACCMODE) == O_WRONLY) { - goto fail; - } - - if (hash_size == 0) hash_size = DEFAULT_HASH_SIZE; - - tdb.read_only = ((open_flags & O_ACCMODE) == O_RDONLY); - - if (name != NULL) { - tdb.fd = open(name, open_flags, mode); - if (tdb.fd == -1) { - goto fail; - } - } - - /* ensure there is only one process initialising at once */ - tdb_brlock(&tdb, GLOBAL_LOCK, LOCK_SET, F_WRLCK, F_SETLKW); - - if (tdb_flags & TDB_CLEAR_IF_FIRST) { - /* we need to zero the database if we are the only - one with it open */ - if (tdb_brlock(&tdb, ACTIVE_LOCK, LOCK_SET, F_WRLCK, F_SETLK) == 0) { - ftruncate(tdb.fd, 0); - tdb_brlock(&tdb, ACTIVE_LOCK, LOCK_CLEAR, F_WRLCK, F_SETLK); - } - } - - /* leave this lock in place */ - tdb_brlock(&tdb, ACTIVE_LOCK, LOCK_SET, F_RDLCK, F_SETLKW); - - if (read(tdb.fd, &tdb.header, sizeof(tdb.header)) != sizeof(tdb.header) || - strcmp(tdb.header.magic_food, TDB_MAGIC_FOOD) != 0 || - tdb.header.version != TDB_VERSION) { - /* its not a valid database - possibly initialise it */ - if (!(open_flags & O_CREAT)) { - goto fail; - } - if (tdb_new_database(&tdb, hash_size) == -1) goto fail; - - lseek(tdb.fd, 0, SEEK_SET); - if (tdb.fd != -1 && read(tdb.fd, &tdb.header, - sizeof(tdb.header)) != - sizeof(tdb.header)) - goto fail; - } - - if (tdb.fd != -1) { - fstat(tdb.fd, &st); - - /* map the database and fill in the return structure */ - tdb.name = (char *)strdup(name); - tdb.map_size = st.st_size; - } - - tdb.locked = (int *)calloc(tdb.header.hash_size+1, - sizeof(tdb.locked[0])); - if (!tdb.locked) { - goto fail; - } - -#if HAVE_MMAP - if (tdb.fd != -1) { - tdb.map_ptr = (void *)mmap(NULL, st.st_size, - tdb.read_only? PROT_READ : PROT_READ|PROT_WRITE, - MAP_SHARED | MAP_FILE, tdb.fd, 0); - } -#endif - - ret = (TDB_CONTEXT *)malloc(sizeof(tdb)); - if (!ret) goto fail; - - *ret = tdb; - -#if TDB_DEBUG - printf("mapped database of hash_size %u map_size=%u\n", - hash_size, tdb.map_size); -#endif - - tdb_brlock(&tdb, GLOBAL_LOCK, LOCK_CLEAR, F_WRLCK, F_SETLKW); - return ret; - - fail: - if (tdb.name) free(tdb.name); - if (tdb.fd != -1) close(tdb.fd); - if (tdb.map_ptr) munmap(tdb.map_ptr, tdb.map_size); - - return NULL; -} - -/* close a database */ -int tdb_close(TDB_CONTEXT *tdb) -{ - if (!tdb) return -1; - - if (tdb->name) free(tdb->name); - if (tdb->fd != -1) close(tdb->fd); - if (tdb->locked) free(tdb->locked); - - if (tdb->map_ptr) { - if (tdb->fd != -1) { - munmap(tdb->map_ptr, tdb->map_size); - } else { - free(tdb->map_ptr); - } - } - - memset(tdb, 0, sizeof(*tdb)); - free(tdb); - - return 0; -} - -/* lock the database. If we already have it locked then don't do anything */ -int tdb_writelock(TDB_CONTEXT *tdb) -{ - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_writelock() called with null context\n"); -#endif - return -1; - } - - return tdb_lock(tdb, -1); -} - -/* unlock the database. */ -int tdb_writeunlock(TDB_CONTEXT *tdb) -{ - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_writeunlock() called with null context\n"); -#endif - return -1; - } - - return tdb_unlock(tdb, -1); -} - -/* lock one hash chain. This is meant to be used to reduce locking - contention - it cannot guarantee how many records will be locked */ -int tdb_lockchain(TDB_CONTEXT *tdb, TDB_DATA key) -{ - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_lockchain() called with null context\n"); -#endif - return -1; - } - - return tdb_lock(tdb, BUCKET(tdb_hash(&key))); -} - - -/* unlock one hash chain */ -int tdb_unlockchain(TDB_CONTEXT *tdb, TDB_DATA key) -{ - if (tdb == NULL) { -#ifdef TDB_DEBUG - printf("tdb_unlockchain() called with null context\n"); -#endif - return -1; - } - - return tdb_unlock(tdb, BUCKET(tdb_hash(&key))); -} |