#include <stdint.h>
#include <glib.h>
+#include <string.h>
-#include "inode.h"
+#include "bluesky.h"
/* Core filesystem. Different proxies, such as the NFSv3 one, interface to
* this, but the core actually tracks the data which is stored. So far we just
* implement an in-memory filesystem, but eventually this will be state which
* is persisted to the cloud. */
+/* Return the current time, in microseconds since the epoch. */
+int64_t bluesky_get_current_time()
+{
+ GTimeVal t;
+ g_get_current_time(&t);
+ return (int64_t)t.tv_sec * 1000000 + t.tv_usec;
+}
+
+/* Update an inode to indicate that a modification was made. This increases
+ * the change counter, updates the ctime to the current time, and optionally
+ * updates the mtime. */
+void bluesky_inode_update_ctime(BlueSkyInode *inode, gboolean update_mtime)
+{
+ int64_t now = bluesky_get_current_time();
+ inode->change_count++;
+ inode->ctime = now;
+ if (update_mtime)
+ inode->mtime = now;
+}
-/* Hash a filename for a directory lookup. The string is hashed to a 64-bit
- * value. */
-uint64_t bluesky_directory_hash(gchar *name)
+/* Compute the HMAC keyed-hash function using the given hash algorithm, data,
+ * and key. */
+void compute_hmac(GChecksumType algo,
+ const guchar *data, gsize data_len,
+ const guchar *key, gsize key_len,
+ guint8 *buffer, gsize *digest_len)
{
- GChecksum *csum = g_checksum_new(G_CHECKSUM_MD5);
- g_checksum_update(csum, (guchar *)name, -1);
+ int block_size;
- guint64 hashbytes[2];
- gsize hashsize = sizeof(hashbytes);
- g_checksum_get_digest(csum, (guint8 *)hashbytes, &hashsize);
- return GUINT64_FROM_LE(hashbytes[0]);
+ switch (algo) {
+ case G_CHECKSUM_MD5:
+ case G_CHECKSUM_SHA1:
+ case G_CHECKSUM_SHA256:
+ block_size = 64;
+ break;
+ default:
+ g_error("Unknown hash algorithm for HMAC: %d\n", algo);
+ }
+
+ gsize digest_size = g_checksum_type_get_length(algo);
+
+ guchar keybuf[block_size];
+ memset(keybuf, 0, block_size);
+ memcpy(keybuf, key, MIN(block_size, key_len));
+ for (int i = 0; i < block_size; i++)
+ keybuf[i] ^= 0x36;
+
+ GChecksum *csum1 = g_checksum_new(algo);
+ g_checksum_update(csum1, keybuf, block_size);
+ g_checksum_update(csum1, data, data_len);
+ guint8 digest[digest_size];
+ g_checksum_get_digest(csum1, digest, &digest_size);
+
+ memset(keybuf, 0, block_size);
+ memcpy(keybuf, key, MIN(block_size, key_len));
+ for (int i = 0; i < block_size; i++)
+ keybuf[i] ^= 0x5c;
+
+ GChecksum *csum2 = g_checksum_new(algo);
+ g_checksum_update(csum2, keybuf, block_size);
+ g_checksum_update(csum2, digest, digest_size);
+
+ g_checksum_get_digest(csum2, buffer, digest_len);
+
+ g_checksum_free(csum1);
+ g_checksum_free(csum2);
}
-/* Return the current time, in microseconds since the epoch. */
-int64_t bluesky_get_current_time()
+/* Unfortunately a glib hash table is only guaranteed to be able to store
+ * 32-bit keys if we use the key directly. If we want 64-bit inode numbers,
+ * we'll have to allocate memory to store the 64-bit inumber, and use a pointer
+ * to it. Rather than allocate the memory for the key, we'll just include a
+ * pointer to the 64-bit inum stored in the inode itself, so that we don't need
+ * to do any more memory management. */
+static guint bluesky_fs_key_hash_func(gconstpointer key)
{
- GTimeVal t;
- g_get_current_time(&t);
- return t.tv_sec * 1000000 + t.tv_usec;
+ uint64_t inum = *(const uint64_t *)key;
+ return (guint)inum;
+}
+
+static gboolean bluesky_fs_key_equal_func(gconstpointer a, gconstpointer b)
+{
+ uint64_t i1 = *(const uint64_t *)a;
+ uint64_t i2 = *(const uint64_t *)b;
+ return i1 == i2;
+}
+
+/* Filesystem-level operations. A filesystem is like a directory tree that we
+ * are willing to export. */
+BlueSkyFS *bluesky_new_fs(gchar *name)
+{
+ BlueSkyFS *fs = g_new0(BlueSkyFS, 1);
+ fs->lock = g_mutex_new();
+ fs->name = g_strdup(name);
+ fs->inodes = g_hash_table_new(bluesky_fs_key_hash_func,
+ bluesky_fs_key_equal_func);
+ fs->next_inum = BLUESKY_ROOT_INUM + 1;
+ fs->store = s3store_new();
+
+ return fs;
}
/* Allocate a fresh inode number which has not been used before within a
return inum;
}
-BlueSkyInode *bluesky_new_inode(uint64_t inum)
+BlueSkyInode *bluesky_new_inode(uint64_t inum, BlueSkyFS *fs,
+ BlueSkyFileType type)
{
BlueSkyInode *i = g_new0(BlueSkyInode, 1);
i->lock = g_mutex_new();
+ i->type = type;
+ i->fs = fs;
i->inum = inum;
+ switch (type) {
+ case BLUESKY_REGULAR:
+ i->blocks = g_array_new(FALSE, TRUE, sizeof(BlueSkyBlock));
+ break;
+ case BLUESKY_DIRECTORY:
+ i->dirents = g_sequence_new(bluesky_dirent_destroy);
+ i->dirhash = g_hash_table_new(g_str_hash, g_str_equal);
+ break;
+ case BLUESKY_BLOCK:
+ case BLUESKY_CHARACTER:
+ case BLUESKY_SYMLINK:
+ case BLUESKY_SOCKET:
+ case BLUESKY_FIFO:
+ break;
+ }
+
return i;
}
-void bluesky_dirent_destroy(BlueSkyDirent *dirent)
+/* Retrieve an inode from the filesystem. Eventually this will be a cache and
+ * so we might need to go fetch the inode from elsewhere; for now all
+ * filesystem state is stored here. */
+BlueSkyInode *bluesky_get_inode(BlueSkyFS *fs, uint64_t inum)
{
- g_free(dirent->name);
- g_free(dirent);
+ BlueSkyInode *inode = NULL;
+
+ g_mutex_lock(fs->lock);
+ inode = (BlueSkyInode *)g_hash_table_lookup(fs->inodes, &inum);
+ g_mutex_unlock(fs->lock);
+
+ return inode;
}
-gint bluesky_dirent_compare(gconstpointer a, gconstpointer b,
- gpointer unused)
+/* Insert an inode into the filesystem inode cache. */
+void bluesky_insert_inode(BlueSkyFS *fs, BlueSkyInode *inode)
{
- /* We can't simply subtract the hash values, since they are 64-bit and the
- * result could overflow when converted to a gint. */
- uint64_t hash1 = ((const BlueSkyDirent *)a)->hash;
- uint64_t hash2 = ((const BlueSkyDirent *)b)->hash;
+ g_mutex_lock(fs->lock);
+ g_hash_table_insert(fs->inodes, &inode->inum, inode);
+ g_mutex_unlock(fs->lock);
+}
+
+/* Mark a given block dirty and make sure that data is faulted in so that it
+ * can be written to. */
+void bluesky_block_touch(BlueSkyInode *inode, uint64_t i)
+{
+ g_return_if_fail(i < inode->blocks->len);
+ BlueSkyBlock *block = &g_array_index(inode->blocks, BlueSkyBlock, i);
+
+ switch (block->type) {
+ case BLUESKY_BLOCK_ZERO:
+ block->data = bluesky_string_new(g_malloc0(BLUESKY_BLOCK_SIZE),
+ BLUESKY_BLOCK_SIZE);
+ break;
+ case BLUESKY_BLOCK_REF:
+ bluesky_block_fetch(inode->fs, block);
+ g_assert(block->type == BLUESKY_BLOCK_CACHED);
+ /* Fall through */
+ case BLUESKY_BLOCK_CACHED:
+ case BLUESKY_BLOCK_DIRTY:
+ block->data = bluesky_string_dup(block->data);
+ break;
+ }
+
+ block->type = BLUESKY_BLOCK_DIRTY;
+}
+
+/* Set the size of a file. This will truncate or extend the file as needed.
+ * Newly-allocated bytes are zeroed. */
+void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size)
+{
+ g_return_if_fail(size <= BLUESKY_MAX_FILE_SIZE);
+
+ if (size == inode->size)
+ return;
+
+ uint64_t blocks = (size + BLUESKY_BLOCK_SIZE - 1) / BLUESKY_BLOCK_SIZE;
+
+ if (blocks > inode->blocks->len) {
+ /* Need to add new blocks to the end of a file. New block structures
+ * are automatically zeroed, which initializes them to be pointers to
+ * zero blocks so we don't need to do any more work. */
+ g_array_set_size(inode->blocks, blocks);
+ } else if (blocks < inode->blocks->len) {
+ /* Delete blocks from a file. Must reclaim memory. */
+ for (guint i = inode->blocks->len; i < blocks; i++) {
+ BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock, i);
+ g_free(b->ref);
+ bluesky_string_unref(b->data);
+ }
+ g_array_set_size(inode->blocks, blocks);
+ }
+
+ /* If the file size is being decreased, ensure that any trailing data in
+ * the last block is zeroed. */
+ if (size < inode->size) {
+ BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock,
+ blocks - 1);
+ if (b->type != BLUESKY_BLOCK_ZERO) {
+ bluesky_block_touch(inode, blocks - 1);
+ int end_offset = size % BLUESKY_BLOCK_SIZE;
+ if (end_offset > 0) {
+ memset(&b->data->data[end_offset], 0,
+ BLUESKY_BLOCK_SIZE - end_offset);
+ }
+ }
+ }
+
+ inode->size = size;
+ bluesky_inode_update_ctime(inode, 1);
+}
+
+void bluesky_file_write(BlueSkyInode *inode, uint64_t offset,
+ const char *data, gint len)
+{
+ g_return_if_fail(inode->type == BLUESKY_REGULAR);
+ g_return_if_fail(offset < inode->size);
+ g_return_if_fail(len <= inode->size - offset);
+
+ if (len == 0)
+ return;
+
+ while (len > 0) {
+ uint64_t block_num = offset / BLUESKY_BLOCK_SIZE;
+ gint block_offset = offset % BLUESKY_BLOCK_SIZE;
+ gint bytes = MIN(BLUESKY_BLOCK_SIZE - block_offset, len);
+
+ bluesky_block_touch(inode, block_num);
+ BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock,
+ block_num);
+ memcpy(&b->data->data[block_offset], data, bytes);
+ bluesky_block_flush(inode->fs, b);
+
+ offset += bytes;
+ data += bytes;
+ len -= bytes;
+ }
+
+ bluesky_inode_update_ctime(inode, 1);
+}
+
+void bluesky_file_read(BlueSkyInode *inode, uint64_t offset,
+ char *buf, gint len)
+{
+ g_return_if_fail(inode->type == BLUESKY_REGULAR);
+ g_return_if_fail(offset < inode->size);
+ g_return_if_fail(len <= inode->size - offset);
+
+ while (len > 0) {
+ uint64_t block_num = offset / BLUESKY_BLOCK_SIZE;
+ gint block_offset = offset % BLUESKY_BLOCK_SIZE;
+ gint bytes = MIN(BLUESKY_BLOCK_SIZE - block_offset, len);
+
+ BlueSkyBlock *b = &g_array_index(inode->blocks, BlueSkyBlock,
+ block_num);
+ switch (b->type) {
+ case BLUESKY_BLOCK_ZERO:
+ memset(buf, 0, bytes);
+ break;
+ case BLUESKY_BLOCK_REF:
+ bluesky_block_fetch(inode->fs, b);
+ /* Fall through */
+ case BLUESKY_BLOCK_CACHED:
+ case BLUESKY_BLOCK_DIRTY:
+ memcpy(buf, &b->data->data[block_offset], bytes);
+ break;
+ }
+
+ offset += bytes;
+ buf += bytes;
+ len -= bytes;
+ }
+}
+
+/* Read the given block from cloud-backed storage if the data is not already
+ * cached. */
+void bluesky_block_fetch(BlueSkyFS *fs, BlueSkyBlock *block)
+{
+ if (block->type != BLUESKY_BLOCK_REF)
+ return;
+
+ g_print("Fetching block from %s\n", block->ref);
+ BlueSkyRCStr *string = s3store_get(fs->store, block->ref);
- if (hash1 < hash2)
- return -1;
- else if (hash1 > hash2)
- return 1;
- else
- return 0;
+ bluesky_string_unref(block->data);
+ block->data = string;
+ block->type = BLUESKY_BLOCK_CACHED;
}
-/* Perform a lookup for a file name within a directory. Returns the inode
- * number if found, or 0 if not (0 is never a valid inode number). Should be
- * called with the inode lock already held. */
-uint64_t bluesky_directory_lookup(BlueSkyInode *inode, gchar *name)
+/* Write the given block to cloud-backed storage and mark it clean. */
+void bluesky_block_flush(BlueSkyFS *fs, BlueSkyBlock *block)
{
- g_return_val_if_fail(inode->type != BLUESKY_DIRECTORY, 0);
- g_return_val_if_fail(inode->dirents != NULL, 0);
+ if (block->type != BLUESKY_BLOCK_DIRTY)
+ return;
- /* First, construct a hash of the file name. Search the directory for a
- * match, then check to see if it does really match. */
- uint64_t hash = bluesky_directory_hash(name);
+ GChecksum *csum = g_checksum_new(G_CHECKSUM_SHA256);
+ g_checksum_update(csum, block->data->data, block->data->len);
+ gchar *name = g_strdup(g_checksum_get_string(csum));
- BlueSkyDirent d = {name, hash, 0};
- GSequenceIter *i = g_sequence_search(inode->dirents, &d,
- bluesky_dirent_compare, NULL);
+ g_print("Flushing block as %s\n", name);
+ s3store_put(fs->store, name, block->data);
+ g_free(block->ref);
+ block->ref = name;
- if (g_sequence_iter_is_end(i))
- return 0;
- BlueSkyDirent *dirent = g_sequence_get(i);
- if (dirent->hash != hash)
- return 0;
- if (g_strcmp0(name, dirent->name) != 0)
- return 0;
+ /* block->type = BLUESKY_BLOCK_CACHED; */
+ bluesky_string_unref(block->data);
+ block->data = NULL;
+ block->type = BLUESKY_BLOCK_REF;
- return dirent->inum;
+ g_checksum_free(csum);
}
projects / bluesky.git / blobdiff