Add a fragment table primitive to libsquashfs

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

2 files changed, 196 insertions, 0 deletions

diff --git a/lib/sqfs/Makemodule.am b/lib/sqfs/Makemodule.am
index e3ed94a..7d44e59 100644
--- a/lib/sqfs/Makemodule.am
+++ b/lib/sqfs/Makemodule.am
@@ -25,6 +25,7 @@ libsquashfs_la_SOURCES += lib/sqfs/data_writer/common.c
 libsquashfs_la_SOURCES += lib/sqfs/data_writer/fileapi.c
 libsquashfs_la_SOURCES += lib/sqfs/str_table.c lib/sqfs/str_table.h
 libsquashfs_la_SOURCES += lib/sqfs/alloc.c lib/sqfs/util.h
+libsquashfs_la_SOURCES += lib/sqfs/frag_table.c include/sqfs/frag_table.h
 libsquashfs_la_CPPFLAGS = $(AM_CPPFLAGS)
 libsquashfs_la_LDFLAGS = $(AM_LDFLAGS)
 libsquashfs_la_CFLAGS = $(AM_CFLAGS) $(PTHREAD_CFLAGS) $(ZLIB_CFLAGS)
diff --git a/lib/sqfs/frag_table.c b/lib/sqfs/frag_table.c
new file mode 100644
index 0000000..3373a3c
--- /dev/null
+++ b/lib/sqfs/frag_table.c
@@ -0,0 +1,195 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * frag_table.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "config.h"
+
+#include "sqfs/frag_table.h"
+#include "sqfs/super.h"
+#include "sqfs/table.h"
+#include "sqfs/error.h"
+#include "sqfs/block.h"
+#include "compat.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+struct sqfs_frag_table_t {
+	size_t capacity;
+	size_t used;
+	sqfs_fragment_t *table;
+};
+
+sqfs_frag_table_t *sqfs_frag_table_create(sqfs_u32 flags)
+{
+	sqfs_frag_table_t *tbl;
+
+	if (flags != 0)
+		return NULL;
+
+	tbl = calloc(1, sizeof(*tbl));
+	if (tbl == NULL)
+		return NULL;
+
+	return tbl;
+}
+
+void sqfs_frag_table_destroy(sqfs_frag_table_t *tbl)
+{
+	free(tbl->table);
+	free(tbl);
+}
+
+int sqfs_frag_table_read(sqfs_frag_table_t *tbl, sqfs_file_t *file,
+			 const sqfs_super_t *super, sqfs_compressor_t *cmp)
+{
+	sqfs_u64 location, lower, upper;
+	void *raw = NULL;
+	size_t size;
+	int err;
+
+	free(tbl->table);
+	tbl->table = NULL;
+	tbl->capacity = 0;
+	tbl->used = 0;
+
+	if (super->flags & SQFS_FLAG_NO_FRAGMENTS)
+		return 0;
+
+	if (super->fragment_table_start == 0xFFFFFFFFFFFFFFFFUL)
+		return 0;
+
+	if (super->fragment_entry_count == 0)
+		return 0;
+
+	if (super->fragment_table_start >= super->bytes_used)
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	/* location must be after inode & directory table,
+	   but before the ID table */
+	if (super->fragment_table_start < super->directory_table_start)
+		return SQFS_ERROR_CORRUPTED;
+
+	if (super->fragment_table_start >= super->id_table_start)
+		return SQFS_ERROR_CORRUPTED;
+
+	location = super->fragment_table_start;
+	lower = super->directory_table_start;
+	upper = super->id_table_start;
+
+	if (super->export_table_start < super->id_table_start)
+		upper = super->export_table_start;
+
+	if (SZ_MUL_OV(super->fragment_entry_count, sizeof(sqfs_fragment_t),
+		      &size)) {
+		return SQFS_ERROR_OVERFLOW;
+	}
+
+	err = sqfs_read_table(file, cmp, size, location, lower, upper, &raw);
+	if (err) {
+		free(raw);
+		return err;
+	}
+
+	tbl->table = raw;
+	tbl->capacity = super->fragment_entry_count;
+	tbl->used = super->fragment_entry_count;
+	return 0;
+}
+
+int sqfs_frag_table_write(sqfs_frag_table_t *tbl, sqfs_file_t *file,
+			  sqfs_super_t *super, sqfs_compressor_t *cmp)
+{
+	size_t i;
+	int err;
+
+	if (tbl->used == 0) {
+		super->fragment_table_start = 0xFFFFFFFFFFFFFFFF;
+		super->flags |= SQFS_FLAG_NO_FRAGMENTS;
+		super->flags &= ~SQFS_FLAG_ALWAYS_FRAGMENTS;
+		super->flags &= ~SQFS_FLAG_UNCOMPRESSED_FRAGMENTS;
+		return 0;
+	}
+
+	err = sqfs_write_table(file, cmp, tbl->table,
+			       sizeof(tbl->table[0]) * tbl->used,
+			       &super->fragment_table_start);
+	if (err)
+		return err;
+
+	super->fragment_entry_count = tbl->used;
+	super->flags &= ~SQFS_FLAG_NO_FRAGMENTS;
+	super->flags |= SQFS_FLAG_ALWAYS_FRAGMENTS;
+	super->flags |= SQFS_FLAG_UNCOMPRESSED_FRAGMENTS;
+
+	for (i = 0; i < tbl->used; ++i) {
+		if (SQFS_IS_BLOCK_COMPRESSED(le32toh(tbl->table[i].size))) {
+			super->flags &= ~SQFS_FLAG_UNCOMPRESSED_FRAGMENTS;
+			break;
+		}
+	}
+
+	return 0;
+}
+
+int sqfs_frag_table_lookup(sqfs_frag_table_t *tbl, sqfs_u32 index,
+			   sqfs_fragment_t *out)
+{
+	if (index >= tbl->used)
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	out->start_offset = le64toh(tbl->table[index].start_offset);
+	out->size = le32toh(tbl->table[index].size);
+	out->pad0 = le32toh(tbl->table[index].pad0);
+	return 0;
+}
+
+int sqfs_frag_table_append(sqfs_frag_table_t *tbl, sqfs_u64 location,
+			   sqfs_u32 size, sqfs_u32 *index)
+{
+	size_t new_sz, total;
+	void *new;
+
+	if (tbl->used == tbl->capacity) {
+		new_sz = tbl->capacity ? tbl->capacity * 2 : 128;
+
+		if (SZ_MUL_OV(new_sz, sizeof(tbl->table[0]), &total))
+			return SQFS_ERROR_OVERFLOW;
+
+		new = realloc(tbl->table, total);
+		if (new == NULL)
+			return SQFS_ERROR_ALLOC;
+
+		tbl->capacity = new_sz;
+		tbl->table = new;
+	}
+
+	if (index != NULL)
+		*index = tbl->used;
+
+	memset(tbl->table + tbl->used, 0, sizeof(tbl->table[0]));
+	tbl->table[tbl->used].start_offset = htole64(location);
+	tbl->table[tbl->used].size = htole32(size);
+
+	tbl->used += 1;
+	return 0;
+}
+
+int sqfs_frag_table_set(sqfs_frag_table_t *tbl, sqfs_u32 index,
+			sqfs_u64 location, sqfs_u32 size)
+{
+	if (index >= tbl->used)
+		return SQFS_ERROR_OUT_OF_BOUNDS;
+
+	tbl->table[index].start_offset = htole64(location);
+	tbl->table[index].size = htole32(size);
+	return 0;
+}
+
+size_t sqfs_frag_table_get_size(sqfs_frag_table_t *tbl)
+{
+	return tbl->used;
+}