Store directory index in generic inode structure

This commit modifies the dir writer to store the directory index directly
in the payload area of the inode it creates. The size of the index in bytes
is stored in a seperate field. Storing the index is moved to the write
inode function.

The read inode function is in turn also modified to read the directory
index from disk and actually store it in the inode structure in memory
for later use.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

3 files changed, 134 insertions, 38 deletions

diff --git a/lib/sqfs/dir_writer.c b/lib/sqfs/dir_writer.c
index 5b8f6b1..a4aebe6 100644
--- a/lib/sqfs/dir_writer.c
+++ b/lib/sqfs/dir_writer.c
@@ -291,10 +291,13 @@ sqfs_inode_generic_t
 			      sqfs_u32 parent_ino)
 {
 	sqfs_inode_generic_t *inode;
+	sqfs_dir_index_t *ent;
 	sqfs_u64 start_block;
 	sqfs_u16 block_offset;
+	index_ent_t *idx;
+	sqfs_u8 *ptr;
 
-	inode = calloc(1, sizeof(*inode));
+	inode = alloc_flex(sizeof(*inode), 1, writer->idx_size);
 	if (inode == NULL)
 		return NULL;
 
@@ -323,32 +326,21 @@ sqfs_inode_generic_t
 		inode->data.dir_ext.xattr_idx = xattr;
 		inode->data.dir_ext.inodex_count =
 			writer->idx_size ? (writer->idx_size - 1) : 0;
-	}
-
-	return inode;
-}
-
-int sqfs_dir_writer_write_index(const sqfs_dir_writer_t *writer,
-				sqfs_meta_writer_t *im)
-{
-	sqfs_dir_index_t ent;
-	index_ent_t *idx;
-	int err;
 
-	for (idx = writer->idx; idx != NULL; idx = idx->next) {
-		ent.start_block = htole32(idx->block);
-		ent.index = htole32(idx->index);
-		ent.size = htole32(idx->ent->name_len - 1);
+		inode->num_dir_idx_bytes = writer->idx_size;
+		ptr = inode->extra;
 
-		err = sqfs_meta_writer_append(im, &ent, sizeof(ent));
-		if (err)
-			return err;
+		for (idx = writer->idx; idx != NULL; idx = idx->next) {
+			ent = (sqfs_dir_index_t *)ptr;
+			ent->start_block = idx->block;
+			ent->index = idx->index;
+			ent->size = idx->ent->name_len - 1;
 
-		err = sqfs_meta_writer_append(im, idx->ent->name,
-					      idx->ent->name_len);
-		if (err)
-			return err;
+			ptr += sizeof(*ent);
+			memcpy(ptr, idx->ent->name, idx->ent->name_len);
+			ptr += idx->ent->name_len;
+		}
 	}
 
-	return 0;
+	return inode;
 }
diff --git a/lib/sqfs/read_inode.c b/lib/sqfs/read_inode.c
index 2887959..f877da1 100644
--- a/lib/sqfs/read_inode.c
+++ b/lib/sqfs/read_inode.c
@@ -11,9 +11,11 @@
 #include "sqfs/error.h"
 #include "sqfs/super.h"
 #include "sqfs/inode.h"
+#include "sqfs/dir.h"
 #include "util.h"
 
 #include <stdlib.h>
+#include <string.h>
 #include <errno.h>
 
 #define SWAB16(x) x = le16toh(x)
@@ -222,6 +224,80 @@ static int read_inode_slink_ext(sqfs_meta_reader_t *ir, sqfs_inode_t *base,
 	return 0;
 }
 
+static int read_inode_dir_ext(sqfs_meta_reader_t *ir, sqfs_inode_t *base,
+			      sqfs_inode_generic_t **result)
+{
+	size_t i, new_sz, index_max, index_used;
+	sqfs_inode_generic_t *out;
+	sqfs_inode_dir_ext_t dir;
+	sqfs_dir_index_t ent;
+	void *new;
+	int err;
+
+	err = sqfs_meta_reader_read(ir, &dir, sizeof(dir));
+	if (err)
+		return err;
+
+	SWAB32(dir.nlink);
+	SWAB32(dir.size);
+	SWAB32(dir.start_block);
+	SWAB32(dir.parent_inode);
+	SWAB16(dir.inodex_count);
+	SWAB16(dir.offset);
+	SWAB32(dir.xattr_idx);
+
+	index_max = dir.size ? 128 : 0;
+	index_used = 0;
+
+	out = alloc_flex(sizeof(*out), 1, index_max);
+	if (out == NULL)
+		return SQFS_ERROR_ALLOC;
+
+	out->base = *base;
+	out->data.dir_ext = dir;
+
+	if (dir.size == 0) {
+		*result = out;
+		return 0;
+	}
+
+	for (i = 0; i <= dir.inodex_count; ++i) {
+		err = sqfs_meta_reader_read(ir, &ent, sizeof(ent));
+		if (err)
+			return err;
+
+		SWAB32(ent.start_block);
+		SWAB32(ent.index);
+		SWAB32(ent.size);
+
+		new_sz = index_max;
+		while (sizeof(ent) + ent.size + 1 > new_sz - index_used)
+			new_sz *= 2;
+
+		if (new_sz > index_max) {
+			new = realloc(out, sizeof(*out) + new_sz);
+			if (new == NULL) {
+				free(out);
+				return SQFS_ERROR_ALLOC;
+			}
+			out = new;
+			index_max = new_sz;
+		}
+
+		memcpy(out->extra + index_used, &ent, sizeof(ent));
+		index_used += sizeof(ent);
+
+		err = sqfs_meta_reader_read(ir, out->extra + index_used,
+					    ent.size + 1);
+		if (err)
+			return err;
+	}
+
+	out->num_dir_idx_bytes = index_used;
+	*result = out;
+	return 0;
+}
+
 int sqfs_meta_reader_read_inode(sqfs_meta_reader_t *ir,
 				const sqfs_super_t *super,
 				sqfs_u64 block_start, size_t offset,
@@ -264,6 +340,8 @@ int sqfs_meta_reader_read_inode(sqfs_meta_reader_t *ir,
 					   result);
 	case SQFS_INODE_EXT_SLINK:
 		return read_inode_slink_ext(ir, &inode, result);
+	case SQFS_INODE_EXT_DIR:
+		return read_inode_dir_ext(ir, &inode, result);
 	default:
 		break;
 	}
@@ -305,19 +383,6 @@ int sqfs_meta_reader_read_inode(sqfs_meta_reader_t *ir,
 			goto fail_free;
 		SWAB32(out->data.ipc.nlink);
 		break;
-	case SQFS_INODE_EXT_DIR:
-		err = sqfs_meta_reader_read(ir, &out->data.dir_ext,
-					    sizeof(out->data.dir_ext));
-		if (err)
-			goto fail_free;
-		SWAB32(out->data.dir_ext.nlink);
-		SWAB32(out->data.dir_ext.size);
-		SWAB32(out->data.dir_ext.start_block);
-		SWAB32(out->data.dir_ext.parent_inode);
-		SWAB16(out->data.dir_ext.inodex_count);
-		SWAB16(out->data.dir_ext.offset);
-		SWAB32(out->data.dir_ext.xattr_idx);
-		break;
 	case SQFS_INODE_EXT_BDEV:
 	case SQFS_INODE_EXT_CDEV:
 		err = sqfs_meta_reader_read(ir, &out->data.dev_ext,
diff --git a/lib/sqfs/write_inode.c b/lib/sqfs/write_inode.c
index af6b1e6..2e69b80 100644
--- a/lib/sqfs/write_inode.c
+++ b/lib/sqfs/write_inode.c
@@ -10,6 +10,7 @@
 #include "sqfs/meta_writer.h"
 #include "sqfs/error.h"
 #include "sqfs/inode.h"
+#include "sqfs/dir.h"
 #include "compat.h"
 
 static int write_block_sizes(sqfs_meta_writer_t *ir,
@@ -25,6 +26,41 @@ static int write_block_sizes(sqfs_meta_writer_t *ir,
 				       sizeof(sqfs_u32) * n->num_file_blocks);
 }
 
+static int write_dir_index(sqfs_meta_writer_t *ir, const sqfs_u8 *data,
+			   size_t count)
+{
+	sqfs_dir_index_t *ent, copy;
+	size_t len;
+	int err;
+
+	while (count > sizeof(*ent)) {
+		ent = (sqfs_dir_index_t *)data;
+		data += sizeof(*ent);
+		count -= sizeof(*ent);
+		len = ent->size + 1;
+
+		if (len > count)
+			return SQFS_ERROR_CORRUPTED;
+
+		copy.start_block = htole32(ent->start_block);
+		copy.index = htole32(ent->index);
+		copy.size = htole32(ent->size);
+
+		err = sqfs_meta_writer_append(ir, &copy, sizeof(copy));
+		if (err)
+			return err;
+
+		err = sqfs_meta_writer_append(ir, data, len);
+		if (err)
+			return err;
+
+		data += len;
+		count -= len;
+	}
+
+	return 0;
+}
+
 int sqfs_meta_writer_write_inode(sqfs_meta_writer_t *ir,
 				 const sqfs_inode_generic_t *n)
 {
@@ -102,7 +138,10 @@ int sqfs_meta_writer_write_inode(sqfs_meta_writer_t *ir,
 			.offset = htole16(n->data.dir_ext.offset),
 			.xattr_idx = htole32(n->data.dir_ext.xattr_idx),
 		};
-		return sqfs_meta_writer_append(ir, &dir, sizeof(dir));
+		ret = sqfs_meta_writer_append(ir, &dir, sizeof(dir));
+		if (ret)
+			return ret;
+		return write_dir_index(ir, n->extra, n->num_dir_idx_bytes);
 	}
 	case SQFS_INODE_EXT_FILE: {
 		sqfs_inode_file_ext_t file = {