X-Git-Url: http://git.vrable.net/?a=blobdiff_plain;f=inode.c;h=162e154cf21f3750acbf7904bfa2997a8d21e727;hb=386250b1e7b69e1050b8eb96402ea764dbc77b25;hp=1c6a083a7aeb825e10f3758859697258cb84d459;hpb=69c35a771a31ff0e6b2b59b640c90d5508064c45;p=bluesky.git

diff --git a/inode.c b/inode.c
index 1c6a083..162e154 100644
--- a/inode.c
+++ b/inode.c
@@ -8,6 +8,7 @@
 
 #include <stdint.h>
 #include <glib.h>
+#include <string.h>
 
 #include "bluesky.h"
 
@@ -36,6 +37,54 @@ void bluesky_inode_update_ctime(BlueSkyInode *inode, gboolean update_mtime)
         inode->mtime = now;
 }
 
+/* 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)
+{
+    int block_size;
+
+    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);
+}
+
 /* 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
@@ -132,6 +181,29 @@ void bluesky_insert_inode(BlueSkyFS *fs, BlueSkyInode *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 = g_malloc0(BLUESKY_BLOCK_SIZE);
+        break;
+    case BLUESKY_BLOCK_REF:
+        /* TODO: Pull in data first */
+        block->data = g_malloc0(BLUESKY_BLOCK_SIZE);
+        break;
+    case BLUESKY_BLOCK_CACHED:
+    case BLUESKY_BLOCK_DIRTY:
+        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)
@@ -141,7 +213,7 @@ void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size)
     if (size == inode->size)
         return;
 
-    uint64_t blocks = (size + BLUESKY_BLOCK_SIZE - 1) / BLUESKY_MAX_FILE_SIZE;
+    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
@@ -158,8 +230,108 @@ void bluesky_file_truncate(BlueSkyInode *inode, uint64_t size)
         g_array_set_size(inode->blocks, blocks);
     }
 
-    /* TODO: Zero out partial blocks if needed? */
+    /* 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[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[block_offset], data, bytes);
+        bluesky_block_flush(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:
+            /* TODO: Pull in data first */
+            memset(buf, 0, bytes);
+            break;
+        case BLUESKY_BLOCK_CACHED:
+        case BLUESKY_BLOCK_DIRTY:
+            memcpy(buf, &b->data[block_offset], bytes);
+            break;
+        }
+
+        offset += bytes;
+        buf += bytes;
+        len -= bytes;
+    }
+}
+
+/* Write the given block to cloud-backed storage and mark it clean. */
+void bluesky_block_flush(BlueSkyBlock *block)
+{
+    if (block->type != BLUESKY_BLOCK_DIRTY)
+        return;
+
+    BlueSkyRCStr *data = bluesky_string_new(g_memdup(block->data,
+                                                     BLUESKY_BLOCK_SIZE),
+                                            BLUESKY_BLOCK_SIZE);
+
+    GChecksum *csum = g_checksum_new(G_CHECKSUM_SHA256);
+    g_checksum_update(csum, data->data, data->len);
+    const gchar *name = g_checksum_get_string(csum);
+
+    g_print("Flushing block as %s\n", name);
+    //memstore_put(store, name, data);
+    g_free(block->ref);
+    block->ref = g_strdup(name);
+    block->type = BLUESKY_BLOCK_CACHED;
+
+    g_checksum_free(csum);
+    bluesky_string_unref(data);
+}