1 files changed, 151 insertions, 1 deletions

diff --git a/src/indexer.c b/src/indexer.c
index c8fd9c25d..1a59f03f1 100644
--- a/src/indexer.c
+++ b/src/indexer.c
@@ -10,6 +10,9 @@
 #include "git2/indexer.h"
 #include "git2/object.h"
 
+#include "commit.h"
+#include "tree.h"
+#include "tag.h"
 #include "pack.h"
 #include "mwindow.h"
 #include "posix.h"
@@ -36,12 +39,15 @@ struct git_indexer {
 		pack_committed :1,
 		have_stream :1,
 		have_delta :1,
-		do_fsync :1;
+		do_fsync :1,
+		do_verify :1;
 	struct git_pack_header hdr;
 	struct git_pack_file *pack;
 	unsigned int mode;
 	git_off_t off;
 	git_off_t entry_start;
+	git_otype entry_type;
+	git_buf entry_data;
 	git_packfile_stream stream;
 	size_t nr_objects;
 	git_vector objects;
@@ -53,6 +59,9 @@ struct git_indexer {
 	void *progress_payload;
 	char objbuf[8*1024];
 
+	/* OIDs referenced from pack objects. Used for verification. */
+	git_oidmap *expected_oids;
+
 	/* Needed to look up objects which we want to inject to fix a thin pack */
 	git_odb *odb;
 
@@ -125,6 +134,11 @@ int git_indexer_new(
 	idx->mode = mode ? mode : GIT_PACK_FILE_MODE;
 	git_hash_ctx_init(&idx->hash_ctx);
 	git_hash_ctx_init(&idx->trailer);
+	git_buf_init(&idx->entry_data, 0);
+	idx->expected_oids = git_oidmap_alloc();
+	GITERR_CHECK_ALLOC(idx->expected_oids);
+
+	idx->do_verify = !!idx->odb;
 
 	if (git_repository__fsync_gitdir)
 		idx->do_fsync = 1;
@@ -210,6 +224,9 @@ static int hash_object_stream(git_indexer*idx, git_packfile_stream *stream)
 		if ((read = git_packfile_stream_read(stream, idx->objbuf, sizeof(idx->objbuf))) < 0)
 			break;
 
+		if (idx->do_verify)
+			git_buf_put(&idx->entry_data, idx->objbuf, read);
+
 		git_hash_update(&idx->hash_ctx, idx->objbuf, read);
 	} while (read > 0);
 
@@ -279,6 +296,97 @@ static int crc_object(uint32_t *crc_out, git_mwindow_file *mwf, git_off_t start,
 	return 0;
 }
 
+static void add_expected_oid(git_indexer *idx, const git_oid *oid)
+{
+	int ret;
+
+	/*
+	 * If we know about that object because it is stored in our ODB or
+	 * because we have already processed it as part of our pack file, we do
+	 * not have to expect it.
+	 */
+	if (!git_odb_exists(idx->odb, oid) &&
+	    !git_oidmap_exists(idx->pack->idx_cache, oid) &&
+	    !git_oidmap_exists(idx->expected_oids, oid)) {
+		    git_oid *dup = git__malloc(sizeof(*oid));
+		    git_oid_cpy(dup, oid);
+		    git_oidmap_put(idx->expected_oids, dup, &ret);
+	}
+}
+
+static int check_object_connectivity(git_indexer *idx, const git_rawobj *obj)
+{
+	git_object *object;
+	size_t keyidx;
+	int error;
+
+	if (obj->type != GIT_OBJ_BLOB &&
+	    obj->type != GIT_OBJ_TREE &&
+	    obj->type != GIT_OBJ_COMMIT &&
+	    obj->type != GIT_OBJ_TAG)
+		return 0;
+
+	if ((error = git_object__from_raw(&object, obj->data, obj->len, obj->type)) < 0)
+		goto out;
+
+	keyidx = git_oidmap_lookup_index(idx->expected_oids, &object->cached.oid);
+	if (git_oidmap_valid_index(idx->expected_oids, keyidx)) {
+		const git_oid *key = git_oidmap_key(idx->expected_oids, keyidx);
+		git__free((git_oid *) key);
+		git_oidmap_delete_at(idx->expected_oids, keyidx);
+	}
+
+	/*
+	 * Check whether this is a known object. If so, we can just continue as
+	 * we assume that the ODB has a complete graph.
+	 */
+	if (git_odb_exists(idx->odb, &object->cached.oid))
+		return 0;
+
+	switch (obj->type) {
+		case GIT_OBJ_TREE:
+		{
+			git_tree *tree = (git_tree *) object;
+			git_tree_entry *entry;
+			size_t i;
+
+			git_array_foreach(tree->entries, i, entry)
+				add_expected_oid(idx, entry->oid);
+
+			break;
+		}
+		case GIT_OBJ_COMMIT:
+		{
+			git_commit *commit = (git_commit *) object;
+			git_oid *parent_oid;
+			size_t i;
+
+			git_array_foreach(commit->parent_ids, i, parent_oid)
+				add_expected_oid(idx, parent_oid);
+
+			add_expected_oid(idx, &commit->tree_id);
+
+			break;
+		}
+		case GIT_OBJ_TAG:
+		{
+			git_tag *tag = (git_tag *) object;
+
+			add_expected_oid(idx, &tag->target);
+
+			break;
+		}
+		case GIT_OBJ_BLOB:
+		default:
+			break;
+	}
+
+out:
+	git_object_free(object);
+
+	return error;
+}
+
 static int store_object(git_indexer *idx)
 {
 	int i, error;
@@ -304,6 +412,17 @@ static int store_object(git_indexer *idx)
 		entry->offset = (uint32_t)entry_start;
 	}
 
+	if (idx->do_verify) {
+		git_rawobj rawobj = {
+		    idx->entry_data.ptr,
+		    idx->entry_data.size,
+		    idx->entry_type
+		};
+
+		if ((error = check_object_connectivity(idx, &rawobj)) < 0)
+			goto on_error;
+	}
+
 	git_oid_cpy(&pentry->sha1, &oid);
 	pentry->offset = entry_start;
 
@@ -549,6 +668,7 @@ static int read_stream_object(git_indexer *idx, git_transfer_progress *stats)
 		git_mwindow_close(&w);
 		idx->entry_start = entry_start;
 		git_hash_init(&idx->hash_ctx);
+		git_buf_clear(&idx->entry_data);
 
 		if (type == GIT_OBJ_REF_DELTA || type == GIT_OBJ_OFS_DELTA) {
 			error = advance_delta_offset(idx, type);
@@ -569,6 +689,7 @@ static int read_stream_object(git_indexer *idx, git_transfer_progress *stats)
 		}
 
 		idx->have_stream = 1;
+		idx->entry_type = type;
 
 		error = git_packfile_stream_open(stream, idx->pack, idx->off);
 		if (error < 0)
@@ -884,6 +1005,10 @@ static int resolve_deltas(git_indexer *idx, git_transfer_progress *stats)
 				return -1;
 			}
 
+			if (idx->do_verify && check_object_connectivity(idx, &obj) < 0)
+				/* TODO: error? continue? */
+				continue;
+
 			if (hash_and_save(idx, &obj, delta->delta_off) < 0)
 				continue;
 
@@ -1014,6 +1139,18 @@ int git_indexer_commit(git_indexer *idx, git_transfer_progress *stats)
 		write_at(idx, &trailer_hash, idx->pack->mwf.size - GIT_OID_RAWSZ, GIT_OID_RAWSZ);
 	}
 
+	/*
+	 * Is the resulting graph fully connected or are we still
+	 * missing some objects? In the second case, we can
+	 * bail out due to an incomplete and thus corrupt
+	 * packfile.
+	 */
+	if (git_oidmap_size(idx->expected_oids) > 0) {
+		giterr_set(GITERR_INDEXER, "packfile is missing %"PRIuZ" objects",
+			git_oidmap_size(idx->expected_oids));
+		return -1;
+	}
+
 	git_vector_sort(&idx->objects);
 
 	/* Use the trailer hash as the pack file name to ensure
@@ -1143,6 +1280,8 @@ on_error:
 
 void git_indexer_free(git_indexer *idx)
 {
+	khiter_t pos;
+
 	if (idx == NULL)
 		return;
 
@@ -1170,7 +1309,18 @@ void git_indexer_free(git_indexer *idx)
 		git_mutex_unlock(&git__mwindow_mutex);
 	}
 
+	for (pos = git_oidmap_begin(idx->expected_oids);
+	    pos != git_oidmap_end(idx->expected_oids); pos++)
+	{
+		if (git_oidmap_has_data(idx->expected_oids, pos)) {
+			git__free((git_oid *) git_oidmap_key(idx->expected_oids, pos));
+			git_oidmap_delete_at(idx->expected_oids, pos);
+		}
+	}
+
 	git_hash_ctx_cleanup(&idx->trailer);
 	git_hash_ctx_cleanup(&idx->hash_ctx);
+	git_buf_dispose(&idx->entry_data);
+	git_oidmap_free(idx->expected_oids);
 	git__free(idx);
 }