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-rw-r--r--tdb/common/io.c473
1 files changed, 473 insertions, 0 deletions
diff --git a/tdb/common/io.c b/tdb/common/io.c
new file mode 100644
index 0000000000..661f761489
--- /dev/null
+++ b/tdb/common/io.c
@@ -0,0 +1,473 @@
+ /*
+ Unix SMB/CIFS implementation.
+
+ trivial database library
+
+ Copyright (C) Andrew Tridgell 1999-2005
+ Copyright (C) Paul `Rusty' Russell 2000
+ Copyright (C) Jeremy Allison 2000-2003
+
+ ** NOTE! The following LGPL license applies to the tdb
+ ** library. This does NOT imply that all of Samba is released
+ ** under the LGPL
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 3 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+
+#include "tdb_private.h"
+
+/* 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
+ note that "len" is the minimum length needed for the db
+*/
+static int tdb_oob(struct tdb_context *tdb, tdb_off_t len, int probe)
+{
+ struct stat st;
+ if (len <= tdb->map_size)
+ return 0;
+ if (tdb->flags & TDB_INTERNAL) {
+ if (!probe) {
+ /* Ensure ecode is set for log fn. */
+ tdb->ecode = TDB_ERR_IO;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob len %d beyond internal malloc size %d\n",
+ (int)len, (int)tdb->map_size));
+ }
+ return TDB_ERRCODE(TDB_ERR_IO, -1);
+ }
+
+ if (fstat(tdb->fd, &st) == -1) {
+ return TDB_ERRCODE(TDB_ERR_IO, -1);
+ }
+
+ if (st.st_size < (size_t)len) {
+ if (!probe) {
+ /* Ensure ecode is set for log fn. */
+ tdb->ecode = TDB_ERR_IO;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_oob len %d beyond eof at %d\n",
+ (int)len, (int)st.st_size));
+ }
+ return TDB_ERRCODE(TDB_ERR_IO, -1);
+ }
+
+ /* Unmap, update size, remap */
+ if (tdb_munmap(tdb) == -1)
+ return TDB_ERRCODE(TDB_ERR_IO, -1);
+ tdb->map_size = st.st_size;
+ tdb_mmap(tdb);
+ return 0;
+}
+
+/* write a lump of data at a specified offset */
+static int tdb_write(struct tdb_context *tdb, tdb_off_t off,
+ const void *buf, tdb_len_t len)
+{
+ if (len == 0) {
+ return 0;
+ }
+
+ if (tdb->read_only || tdb->traverse_read) {
+ tdb->ecode = TDB_ERR_RDONLY;
+ return -1;
+ }
+
+ if (tdb->methods->tdb_oob(tdb, off + len, 0) != 0)
+ return -1;
+
+ if (tdb->map_ptr) {
+ memcpy(off + (char *)tdb->map_ptr, buf, len);
+ } else {
+ ssize_t written = pwrite(tdb->fd, buf, len, off);
+ if ((written != (ssize_t)len) && (written != -1)) {
+ /* try once more */
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_write: wrote only "
+ "%d of %d bytes at %d, trying once more\n",
+ (int)written, len, off));
+ errno = ENOSPC;
+ written = pwrite(tdb->fd, (const void *)((const char *)buf+written),
+ len-written,
+ off+written);
+ }
+ if (written == -1) {
+ /* Ensure ecode is set for log fn. */
+ tdb->ecode = TDB_ERR_IO;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_write failed at %d "
+ "len=%d (%s)\n", off, len, strerror(errno)));
+ return TDB_ERRCODE(TDB_ERR_IO, -1);
+ } else if (written != (ssize_t)len) {
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_write: failed to "
+ "write %d bytes at %d in two attempts\n",
+ len, off));
+ errno = ENOSPC;
+ return TDB_ERRCODE(TDB_ERR_IO, -1);
+ }
+ }
+ return 0;
+}
+
+/* Endian conversion: we only ever deal with 4 byte quantities */
+void *tdb_convert(void *buf, uint32_t size)
+{
+ uint32_t i, *p = (uint32_t *)buf;
+ for (i = 0; i < size / 4; i++)
+ p[i] = TDB_BYTEREV(p[i]);
+ return buf;
+}
+
+
+/* read a lump of data at a specified offset, maybe convert */
+static int tdb_read(struct tdb_context *tdb, tdb_off_t off, void *buf,
+ tdb_len_t len, int cv)
+{
+ if (tdb->methods->tdb_oob(tdb, off + len, 0) != 0) {
+ return -1;
+ }
+
+ if (tdb->map_ptr) {
+ memcpy(buf, off + (char *)tdb->map_ptr, len);
+ } else {
+ ssize_t ret = pread(tdb->fd, buf, len, off);
+ if (ret != (ssize_t)len) {
+ /* Ensure ecode is set for log fn. */
+ tdb->ecode = TDB_ERR_IO;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_read failed at %d "
+ "len=%d ret=%d (%s) map_size=%d\n",
+ (int)off, (int)len, (int)ret, strerror(errno),
+ (int)tdb->map_size));
+ return TDB_ERRCODE(TDB_ERR_IO, -1);
+ }
+ }
+ if (cv) {
+ tdb_convert(buf, len);
+ }
+ return 0;
+}
+
+
+
+/*
+ do an unlocked scan of the hash table heads to find the next non-zero head. The value
+ will then be confirmed with the lock held
+*/
+static void tdb_next_hash_chain(struct tdb_context *tdb, uint32_t *chain)
+{
+ uint32_t h = *chain;
+ if (tdb->map_ptr) {
+ for (;h < tdb->header.hash_size;h++) {
+ if (0 != *(uint32_t *)(TDB_HASH_TOP(h) + (unsigned char *)tdb->map_ptr)) {
+ break;
+ }
+ }
+ } else {
+ uint32_t off=0;
+ for (;h < tdb->header.hash_size;h++) {
+ if (tdb_ofs_read(tdb, TDB_HASH_TOP(h), &off) != 0 || off != 0) {
+ break;
+ }
+ }
+ }
+ (*chain) = h;
+}
+
+
+int tdb_munmap(struct tdb_context *tdb)
+{
+ if (tdb->flags & TDB_INTERNAL)
+ return 0;
+
+#ifdef HAVE_MMAP
+ if (tdb->map_ptr) {
+ int ret;
+
+ ret = munmap(tdb->map_ptr, tdb->map_size);
+ if (ret != 0)
+ return ret;
+ }
+#endif
+ tdb->map_ptr = NULL;
+ return 0;
+}
+
+void tdb_mmap(struct tdb_context *tdb)
+{
+ if (tdb->flags & TDB_INTERNAL)
+ return;
+
+#ifdef HAVE_MMAP
+ if (!(tdb->flags & TDB_NOMMAP)) {
+ tdb->map_ptr = mmap(NULL, tdb->map_size,
+ PROT_READ|(tdb->read_only? 0:PROT_WRITE),
+ MAP_SHARED|MAP_FILE, tdb->fd, 0);
+
+ /*
+ * NB. When mmap fails it returns MAP_FAILED *NOT* NULL !!!!
+ */
+
+ if (tdb->map_ptr == MAP_FAILED) {
+ tdb->map_ptr = NULL;
+ TDB_LOG((tdb, TDB_DEBUG_WARNING, "tdb_mmap failed for size %d (%s)\n",
+ tdb->map_size, strerror(errno)));
+ }
+ } else {
+ tdb->map_ptr = NULL;
+ }
+#else
+ tdb->map_ptr = NULL;
+#endif
+}
+
+/* expand a file. we prefer to use ftruncate, as that is what posix
+ says to use for mmap expansion */
+static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t addition)
+{
+ char buf[8192];
+
+ if (tdb->read_only || tdb->traverse_read) {
+ tdb->ecode = TDB_ERR_RDONLY;
+ return -1;
+ }
+
+ if (ftruncate(tdb->fd, size+addition) == -1) {
+ char b = 0;
+ ssize_t written = pwrite(tdb->fd, &b, 1, (size+addition) - 1);
+ if (written == 0) {
+ /* try once more, potentially revealing errno */
+ written = pwrite(tdb->fd, &b, 1, (size+addition) - 1);
+ }
+ if (written == 0) {
+ /* again - give up, guessing errno */
+ errno = ENOSPC;
+ }
+ if (written != 1) {
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file to %d failed (%s)\n",
+ size+addition, strerror(errno)));
+ return -1;
+ }
+ }
+
+ /* now fill the file with something. This ensures that the
+ file isn't sparse, which would be very bad if we ran out of
+ disk. This must be done with write, not via mmap */
+ memset(buf, TDB_PAD_BYTE, sizeof(buf));
+ while (addition) {
+ size_t n = addition>sizeof(buf)?sizeof(buf):addition;
+ ssize_t written = pwrite(tdb->fd, buf, n, size);
+ if (written == 0) {
+ /* prevent infinite loops: try _once_ more */
+ written = pwrite(tdb->fd, buf, n, size);
+ }
+ if (written == 0) {
+ /* give up, trying to provide a useful errno */
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write "
+ "returned 0 twice: giving up!\n"));
+ errno = ENOSPC;
+ return -1;
+ } else if (written == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_FATAL, "expand_file write of "
+ "%d bytes failed (%s)\n", (int)n,
+ strerror(errno)));
+ return -1;
+ } else if (written != n) {
+ TDB_LOG((tdb, TDB_DEBUG_WARNING, "expand_file: wrote "
+ "only %d of %d bytes - retrying\n", (int)written,
+ (int)n));
+ }
+ addition -= written;
+ size += written;
+ }
+ return 0;
+}
+
+
+/* expand the database at least size bytes by expanding the underlying
+ file and doing the mmap again if necessary */
+int tdb_expand(struct tdb_context *tdb, tdb_off_t size)
+{
+ struct list_struct rec;
+ tdb_off_t offset, new_size;
+
+ if (tdb_lock(tdb, -1, F_WRLCK) == -1) {
+ TDB_LOG((tdb, TDB_DEBUG_ERROR, "lock failed in tdb_expand\n"));
+ return -1;
+ }
+
+ /* must know about any previous expansions by another process */
+ tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1);
+
+ /* always make room for at least 100 more records, and at
+ least 25% more space. Round the database up to a multiple
+ of the page size */
+ new_size = MAX(tdb->map_size + size*100, tdb->map_size * 1.25);
+ size = TDB_ALIGN(new_size, tdb->page_size) - tdb->map_size;
+
+ if (!(tdb->flags & TDB_INTERNAL))
+ tdb_munmap(tdb);
+
+ /*
+ * We must ensure the file is unmapped before doing this
+ * to ensure consistency with systems like OpenBSD where
+ * writes and mmaps are not consistent.
+ */
+
+ /* expand the file itself */
+ if (!(tdb->flags & TDB_INTERNAL)) {
+ if (tdb->methods->tdb_expand_file(tdb, tdb->map_size, size) != 0)
+ goto fail;
+ }
+
+ tdb->map_size += size;
+
+ if (tdb->flags & TDB_INTERNAL) {
+ char *new_map_ptr = (char *)realloc(tdb->map_ptr,
+ tdb->map_size);
+ if (!new_map_ptr) {
+ tdb->map_size -= size;
+ goto fail;
+ }
+ tdb->map_ptr = new_map_ptr;
+ } else {
+ /*
+ * We must ensure the file is remapped before adding the space
+ * to ensure consistency with systems like OpenBSD where
+ * writes and mmaps are not consistent.
+ */
+
+ /* We're ok if the mmap fails as we'll fallback to read/write */
+ tdb_mmap(tdb);
+ }
+
+ /* form a new freelist record */
+ memset(&rec,'\0',sizeof(rec));
+ rec.rec_len = size - sizeof(rec);
+
+ /* link it into the free list */
+ offset = tdb->map_size - size;
+ if (tdb_free(tdb, offset, &rec) == -1)
+ goto fail;
+
+ tdb_unlock(tdb, -1, F_WRLCK);
+ return 0;
+ fail:
+ tdb_unlock(tdb, -1, F_WRLCK);
+ return -1;
+}
+
+/* read/write a tdb_off_t */
+int tdb_ofs_read(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d)
+{
+ return tdb->methods->tdb_read(tdb, offset, (char*)d, sizeof(*d), DOCONV());
+}
+
+int tdb_ofs_write(struct tdb_context *tdb, tdb_off_t offset, tdb_off_t *d)
+{
+ tdb_off_t off = *d;
+ return tdb->methods->tdb_write(tdb, offset, CONVERT(off), sizeof(*d));
+}
+
+
+/* read a lump of data, allocating the space for it */
+unsigned char *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len)
+{
+ unsigned char *buf;
+
+ /* some systems don't like zero length malloc */
+ if (len == 0) {
+ len = 1;
+ }
+
+ if (!(buf = (unsigned char *)malloc(len))) {
+ /* Ensure ecode is set for log fn. */
+ tdb->ecode = TDB_ERR_OOM;
+ TDB_LOG((tdb, TDB_DEBUG_ERROR,"tdb_alloc_read malloc failed len=%d (%s)\n",
+ len, strerror(errno)));
+ return TDB_ERRCODE(TDB_ERR_OOM, buf);
+ }
+ if (tdb->methods->tdb_read(tdb, offset, buf, len, 0) == -1) {
+ SAFE_FREE(buf);
+ return NULL;
+ }
+ return buf;
+}
+
+/* Give a piece of tdb data to a parser */
+
+int tdb_parse_data(struct tdb_context *tdb, TDB_DATA key,
+ tdb_off_t offset, tdb_len_t len,
+ int (*parser)(TDB_DATA key, TDB_DATA data,
+ void *private_data),
+ void *private_data)
+{
+ TDB_DATA data;
+ int result;
+
+ data.dsize = len;
+
+ if ((tdb->transaction == NULL) && (tdb->map_ptr != NULL)) {
+ /*
+ * Optimize by avoiding the malloc/memcpy/free, point the
+ * parser directly at the mmap area.
+ */
+ if (tdb->methods->tdb_oob(tdb, offset+len, 0) != 0) {
+ return -1;
+ }
+ data.dptr = offset + (unsigned char *)tdb->map_ptr;
+ return parser(key, data, private_data);
+ }
+
+ if (!(data.dptr = tdb_alloc_read(tdb, offset, len))) {
+ return -1;
+ }
+
+ result = parser(key, data, private_data);
+ free(data.dptr);
+ return result;
+}
+
+/* read/write a record */
+int tdb_rec_read(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec)
+{
+ if (tdb->methods->tdb_read(tdb, offset, rec, sizeof(*rec),DOCONV()) == -1)
+ return -1;
+ if (TDB_BAD_MAGIC(rec)) {
+ /* Ensure ecode is set for log fn. */
+ tdb->ecode = TDB_ERR_CORRUPT;
+ TDB_LOG((tdb, TDB_DEBUG_FATAL,"tdb_rec_read bad magic 0x%x at offset=%d\n", rec->magic, offset));
+ return TDB_ERRCODE(TDB_ERR_CORRUPT, -1);
+ }
+ return tdb->methods->tdb_oob(tdb, rec->next+sizeof(*rec), 0);
+}
+
+int tdb_rec_write(struct tdb_context *tdb, tdb_off_t offset, struct list_struct *rec)
+{
+ struct list_struct r = *rec;
+ return tdb->methods->tdb_write(tdb, offset, CONVERT(r), sizeof(r));
+}
+
+static const struct tdb_methods io_methods = {
+ tdb_read,
+ tdb_write,
+ tdb_next_hash_chain,
+ tdb_oob,
+ tdb_expand_file,
+ tdb_brlock
+};
+
+/*
+ initialise the default methods table
+*/
+void tdb_io_init(struct tdb_context *tdb)
+{
+ tdb->methods = &io_methods;
+}
generated by cgit (git 2.34.1) at 2024-11-22 09:48:21 +0000