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-rw-r--r--builtin/unpack-objects.c696
1 files changed, 696 insertions, 0 deletions
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
new file mode 100644
index 0000000..fef7423
--- /dev/null
+++ b/builtin/unpack-objects.c
@@ -0,0 +1,696 @@
+#include "builtin.h"
+#include "bulk-checkin.h"
+#include "config.h"
+#include "environment.h"
+#include "gettext.h"
+#include "git-zlib.h"
+#include "hex.h"
+#include "object-store-ll.h"
+#include "object.h"
+#include "delta.h"
+#include "pack.h"
+#include "blob.h"
+#include "commit.h"
+#include "replace-object.h"
+#include "strbuf.h"
+#include "tag.h"
+#include "tree.h"
+#include "tree-walk.h"
+#include "progress.h"
+#include "decorate.h"
+#include "fsck.h"
+
+static int dry_run, quiet, recover, has_errors, strict;
+static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict]";
+
+/* We always read in 4kB chunks. */
+static unsigned char buffer[4096];
+static unsigned int offset, len;
+static off_t consumed_bytes;
+static off_t max_input_size;
+static git_hash_ctx ctx;
+static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
+static struct progress *progress;
+
+/*
+ * When running under --strict mode, objects whose reachability are
+ * suspect are kept in core without getting written in the object
+ * store.
+ */
+struct obj_buffer {
+ char *buffer;
+ unsigned long size;
+};
+
+static struct decoration obj_decorate;
+
+static struct obj_buffer *lookup_object_buffer(struct object *base)
+{
+ return lookup_decoration(&obj_decorate, base);
+}
+
+static void add_object_buffer(struct object *object, char *buffer, unsigned long size)
+{
+ struct obj_buffer *obj;
+ CALLOC_ARRAY(obj, 1);
+ obj->buffer = buffer;
+ obj->size = size;
+ if (add_decoration(&obj_decorate, object, obj))
+ die("object %s tried to add buffer twice!", oid_to_hex(&object->oid));
+}
+
+/*
+ * Make sure at least "min" bytes are available in the buffer, and
+ * return the pointer to the buffer.
+ */
+static void *fill(int min)
+{
+ if (min <= len)
+ return buffer + offset;
+ if (min > sizeof(buffer))
+ die("cannot fill %d bytes", min);
+ if (offset) {
+ the_hash_algo->update_fn(&ctx, buffer, offset);
+ memmove(buffer, buffer + offset, len);
+ offset = 0;
+ }
+ do {
+ ssize_t ret = xread(0, buffer + len, sizeof(buffer) - len);
+ if (ret <= 0) {
+ if (!ret)
+ die("early EOF");
+ die_errno("read error on input");
+ }
+ len += ret;
+ } while (len < min);
+ return buffer;
+}
+
+static void use(int bytes)
+{
+ if (bytes > len)
+ die("used more bytes than were available");
+ len -= bytes;
+ offset += bytes;
+
+ /* make sure off_t is sufficiently large not to wrap */
+ if (signed_add_overflows(consumed_bytes, bytes))
+ die("pack too large for current definition of off_t");
+ consumed_bytes += bytes;
+ if (max_input_size && consumed_bytes > max_input_size)
+ die(_("pack exceeds maximum allowed size"));
+ display_throughput(progress, consumed_bytes);
+}
+
+/*
+ * Decompress zstream from the standard input into a newly
+ * allocated buffer of specified size and return the buffer.
+ * The caller is responsible to free the returned buffer.
+ *
+ * But for dry_run mode, "get_data()" is only used to check the
+ * integrity of data, and the returned buffer is not used at all.
+ * Therefore, in dry_run mode, "get_data()" will release the small
+ * allocated buffer which is reused to hold temporary zstream output
+ * and return NULL instead of returning garbage data.
+ */
+static void *get_data(unsigned long size)
+{
+ git_zstream stream;
+ unsigned long bufsize = dry_run && size > 8192 ? 8192 : size;
+ void *buf = xmallocz(bufsize);
+
+ memset(&stream, 0, sizeof(stream));
+
+ stream.next_out = buf;
+ stream.avail_out = bufsize;
+ stream.next_in = fill(1);
+ stream.avail_in = len;
+ git_inflate_init(&stream);
+
+ for (;;) {
+ int ret = git_inflate(&stream, 0);
+ use(len - stream.avail_in);
+ if (stream.total_out == size && ret == Z_STREAM_END)
+ break;
+ if (ret != Z_OK) {
+ error("inflate returned %d", ret);
+ FREE_AND_NULL(buf);
+ if (!recover)
+ exit(1);
+ has_errors = 1;
+ break;
+ }
+ stream.next_in = fill(1);
+ stream.avail_in = len;
+ if (dry_run) {
+ /* reuse the buffer in dry_run mode */
+ stream.next_out = buf;
+ stream.avail_out = bufsize > size - stream.total_out ?
+ size - stream.total_out :
+ bufsize;
+ }
+ }
+ git_inflate_end(&stream);
+ if (dry_run)
+ FREE_AND_NULL(buf);
+ return buf;
+}
+
+struct delta_info {
+ struct object_id base_oid;
+ unsigned nr;
+ off_t base_offset;
+ unsigned long size;
+ void *delta;
+ struct delta_info *next;
+};
+
+static struct delta_info *delta_list;
+
+static void add_delta_to_list(unsigned nr, const struct object_id *base_oid,
+ off_t base_offset,
+ void *delta, unsigned long size)
+{
+ struct delta_info *info = xmalloc(sizeof(*info));
+
+ oidcpy(&info->base_oid, base_oid);
+ info->base_offset = base_offset;
+ info->size = size;
+ info->delta = delta;
+ info->nr = nr;
+ info->next = delta_list;
+ delta_list = info;
+}
+
+struct obj_info {
+ off_t offset;
+ struct object_id oid;
+ struct object *obj;
+};
+
+/* Remember to update object flag allocation in object.h */
+#define FLAG_OPEN (1u<<20)
+#define FLAG_WRITTEN (1u<<21)
+
+static struct obj_info *obj_list;
+static unsigned nr_objects;
+
+/*
+ * Called only from check_object() after it verified this object
+ * is Ok.
+ */
+static void write_cached_object(struct object *obj, struct obj_buffer *obj_buf)
+{
+ struct object_id oid;
+
+ if (write_object_file(obj_buf->buffer, obj_buf->size,
+ obj->type, &oid) < 0)
+ die("failed to write object %s", oid_to_hex(&obj->oid));
+ obj->flags |= FLAG_WRITTEN;
+}
+
+/*
+ * At the very end of the processing, write_rest() scans the objects
+ * that have reachability requirements and calls this function.
+ * Verify its reachability and validity recursively and write it out.
+ */
+static int check_object(struct object *obj, enum object_type type,
+ void *data UNUSED,
+ struct fsck_options *options UNUSED)
+{
+ struct obj_buffer *obj_buf;
+
+ if (!obj)
+ return 1;
+
+ if (obj->flags & FLAG_WRITTEN)
+ return 0;
+
+ if (type != OBJ_ANY && obj->type != type)
+ die("object type mismatch");
+
+ if (!(obj->flags & FLAG_OPEN)) {
+ unsigned long size;
+ int type = oid_object_info(the_repository, &obj->oid, &size);
+ if (type != obj->type || type <= 0)
+ die("object of unexpected type");
+ obj->flags |= FLAG_WRITTEN;
+ return 0;
+ }
+
+ obj_buf = lookup_object_buffer(obj);
+ if (!obj_buf)
+ die("Whoops! Cannot find object '%s'", oid_to_hex(&obj->oid));
+ if (fsck_object(obj, obj_buf->buffer, obj_buf->size, &fsck_options))
+ die("fsck error in packed object");
+ fsck_options.walk = check_object;
+ if (fsck_walk(obj, NULL, &fsck_options))
+ die("Error on reachable objects of %s", oid_to_hex(&obj->oid));
+ write_cached_object(obj, obj_buf);
+ return 0;
+}
+
+static void write_rest(void)
+{
+ unsigned i;
+ for (i = 0; i < nr_objects; i++) {
+ if (obj_list[i].obj)
+ check_object(obj_list[i].obj, OBJ_ANY, NULL, NULL);
+ }
+}
+
+static void added_object(unsigned nr, enum object_type type,
+ void *data, unsigned long size);
+
+/*
+ * Write out nr-th object from the list, now we know the contents
+ * of it. Under --strict, this buffers structured objects in-core,
+ * to be checked at the end.
+ */
+static void write_object(unsigned nr, enum object_type type,
+ void *buf, unsigned long size)
+{
+ if (!strict) {
+ if (write_object_file(buf, size, type,
+ &obj_list[nr].oid) < 0)
+ die("failed to write object");
+ added_object(nr, type, buf, size);
+ free(buf);
+ obj_list[nr].obj = NULL;
+ } else if (type == OBJ_BLOB) {
+ struct blob *blob;
+ if (write_object_file(buf, size, type,
+ &obj_list[nr].oid) < 0)
+ die("failed to write object");
+ added_object(nr, type, buf, size);
+ free(buf);
+
+ blob = lookup_blob(the_repository, &obj_list[nr].oid);
+ if (blob)
+ blob->object.flags |= FLAG_WRITTEN;
+ else
+ die("invalid blob object");
+ obj_list[nr].obj = NULL;
+ } else {
+ struct object *obj;
+ int eaten;
+ hash_object_file(the_hash_algo, buf, size, type,
+ &obj_list[nr].oid);
+ added_object(nr, type, buf, size);
+ obj = parse_object_buffer(the_repository, &obj_list[nr].oid,
+ type, size, buf,
+ &eaten);
+ if (!obj)
+ die("invalid %s", type_name(type));
+ add_object_buffer(obj, buf, size);
+ obj->flags |= FLAG_OPEN;
+ obj_list[nr].obj = obj;
+ }
+}
+
+static void resolve_delta(unsigned nr, enum object_type type,
+ void *base, unsigned long base_size,
+ void *delta, unsigned long delta_size)
+{
+ void *result;
+ unsigned long result_size;
+
+ result = patch_delta(base, base_size,
+ delta, delta_size,
+ &result_size);
+ if (!result)
+ die("failed to apply delta");
+ free(delta);
+ write_object(nr, type, result, result_size);
+}
+
+/*
+ * We now know the contents of an object (which is nr-th in the pack);
+ * resolve all the deltified objects that are based on it.
+ */
+static void added_object(unsigned nr, enum object_type type,
+ void *data, unsigned long size)
+{
+ struct delta_info **p = &delta_list;
+ struct delta_info *info;
+
+ while ((info = *p) != NULL) {
+ if (oideq(&info->base_oid, &obj_list[nr].oid) ||
+ info->base_offset == obj_list[nr].offset) {
+ *p = info->next;
+ p = &delta_list;
+ resolve_delta(info->nr, type, data, size,
+ info->delta, info->size);
+ free(info);
+ continue;
+ }
+ p = &info->next;
+ }
+}
+
+static void unpack_non_delta_entry(enum object_type type, unsigned long size,
+ unsigned nr)
+{
+ void *buf = get_data(size);
+
+ if (buf)
+ write_object(nr, type, buf, size);
+}
+
+struct input_zstream_data {
+ git_zstream *zstream;
+ unsigned char buf[8192];
+ int status;
+};
+
+static const void *feed_input_zstream(struct input_stream *in_stream,
+ unsigned long *readlen)
+{
+ struct input_zstream_data *data = in_stream->data;
+ git_zstream *zstream = data->zstream;
+ void *in = fill(1);
+
+ if (in_stream->is_finished) {
+ *readlen = 0;
+ return NULL;
+ }
+
+ zstream->next_out = data->buf;
+ zstream->avail_out = sizeof(data->buf);
+ zstream->next_in = in;
+ zstream->avail_in = len;
+
+ data->status = git_inflate(zstream, 0);
+
+ in_stream->is_finished = data->status != Z_OK;
+ use(len - zstream->avail_in);
+ *readlen = sizeof(data->buf) - zstream->avail_out;
+
+ return data->buf;
+}
+
+static void stream_blob(unsigned long size, unsigned nr)
+{
+ git_zstream zstream = { 0 };
+ struct input_zstream_data data = { 0 };
+ struct input_stream in_stream = {
+ .read = feed_input_zstream,
+ .data = &data,
+ };
+ struct obj_info *info = &obj_list[nr];
+
+ data.zstream = &zstream;
+ git_inflate_init(&zstream);
+
+ if (stream_loose_object(&in_stream, size, &info->oid))
+ die(_("failed to write object in stream"));
+
+ if (data.status != Z_STREAM_END)
+ die(_("inflate returned (%d)"), data.status);
+ git_inflate_end(&zstream);
+
+ if (strict) {
+ struct blob *blob = lookup_blob(the_repository, &info->oid);
+
+ if (!blob)
+ die(_("invalid blob object from stream"));
+ blob->object.flags |= FLAG_WRITTEN;
+ }
+ info->obj = NULL;
+}
+
+static int resolve_against_held(unsigned nr, const struct object_id *base,
+ void *delta_data, unsigned long delta_size)
+{
+ struct object *obj;
+ struct obj_buffer *obj_buffer;
+ obj = lookup_object(the_repository, base);
+ if (!obj)
+ return 0;
+ obj_buffer = lookup_object_buffer(obj);
+ if (!obj_buffer)
+ return 0;
+ resolve_delta(nr, obj->type, obj_buffer->buffer,
+ obj_buffer->size, delta_data, delta_size);
+ return 1;
+}
+
+static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
+ unsigned nr)
+{
+ void *delta_data, *base;
+ unsigned long base_size;
+ struct object_id base_oid;
+
+ if (type == OBJ_REF_DELTA) {
+ oidread(&base_oid, fill(the_hash_algo->rawsz));
+ use(the_hash_algo->rawsz);
+ delta_data = get_data(delta_size);
+ if (!delta_data)
+ return;
+ if (repo_has_object_file(the_repository, &base_oid))
+ ; /* Ok we have this one */
+ else if (resolve_against_held(nr, &base_oid,
+ delta_data, delta_size))
+ return; /* we are done */
+ else {
+ /* cannot resolve yet --- queue it */
+ oidclr(&obj_list[nr].oid);
+ add_delta_to_list(nr, &base_oid, 0, delta_data, delta_size);
+ return;
+ }
+ } else {
+ unsigned base_found = 0;
+ unsigned char *pack, c;
+ off_t base_offset;
+ unsigned lo, mid, hi;
+
+ pack = fill(1);
+ c = *pack;
+ use(1);
+ base_offset = c & 127;
+ while (c & 128) {
+ base_offset += 1;
+ if (!base_offset || MSB(base_offset, 7))
+ die("offset value overflow for delta base object");
+ pack = fill(1);
+ c = *pack;
+ use(1);
+ base_offset = (base_offset << 7) + (c & 127);
+ }
+ base_offset = obj_list[nr].offset - base_offset;
+ if (base_offset <= 0 || base_offset >= obj_list[nr].offset)
+ die("offset value out of bound for delta base object");
+
+ delta_data = get_data(delta_size);
+ if (!delta_data)
+ return;
+ lo = 0;
+ hi = nr;
+ while (lo < hi) {
+ mid = lo + (hi - lo) / 2;
+ if (base_offset < obj_list[mid].offset) {
+ hi = mid;
+ } else if (base_offset > obj_list[mid].offset) {
+ lo = mid + 1;
+ } else {
+ oidcpy(&base_oid, &obj_list[mid].oid);
+ base_found = !is_null_oid(&base_oid);
+ break;
+ }
+ }
+ if (!base_found) {
+ /*
+ * The delta base object is itself a delta that
+ * has not been resolved yet.
+ */
+ oidclr(&obj_list[nr].oid);
+ add_delta_to_list(nr, null_oid(), base_offset,
+ delta_data, delta_size);
+ return;
+ }
+ }
+
+ if (resolve_against_held(nr, &base_oid, delta_data, delta_size))
+ return;
+
+ base = repo_read_object_file(the_repository, &base_oid, &type,
+ &base_size);
+ if (!base) {
+ error("failed to read delta-pack base object %s",
+ oid_to_hex(&base_oid));
+ if (!recover)
+ exit(1);
+ has_errors = 1;
+ return;
+ }
+ resolve_delta(nr, type, base, base_size, delta_data, delta_size);
+ free(base);
+}
+
+static void unpack_one(unsigned nr)
+{
+ unsigned shift;
+ unsigned char *pack;
+ unsigned long size, c;
+ enum object_type type;
+
+ obj_list[nr].offset = consumed_bytes;
+
+ pack = fill(1);
+ c = *pack;
+ use(1);
+ type = (c >> 4) & 7;
+ size = (c & 15);
+ shift = 4;
+ while (c & 0x80) {
+ pack = fill(1);
+ c = *pack;
+ use(1);
+ size += (c & 0x7f) << shift;
+ shift += 7;
+ }
+
+ switch (type) {
+ case OBJ_BLOB:
+ if (!dry_run && size > big_file_threshold) {
+ stream_blob(size, nr);
+ return;
+ }
+ /* fallthrough */
+ case OBJ_COMMIT:
+ case OBJ_TREE:
+ case OBJ_TAG:
+ unpack_non_delta_entry(type, size, nr);
+ return;
+ case OBJ_REF_DELTA:
+ case OBJ_OFS_DELTA:
+ unpack_delta_entry(type, size, nr);
+ return;
+ default:
+ error("bad object type %d", type);
+ has_errors = 1;
+ if (recover)
+ return;
+ exit(1);
+ }
+}
+
+static void unpack_all(void)
+{
+ int i;
+ struct pack_header *hdr = fill(sizeof(struct pack_header));
+
+ nr_objects = ntohl(hdr->hdr_entries);
+
+ if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
+ die("bad pack file");
+ if (!pack_version_ok(hdr->hdr_version))
+ die("unknown pack file version %"PRIu32,
+ ntohl(hdr->hdr_version));
+ use(sizeof(struct pack_header));
+
+ if (!quiet)
+ progress = start_progress(_("Unpacking objects"), nr_objects);
+ CALLOC_ARRAY(obj_list, nr_objects);
+ begin_odb_transaction();
+ for (i = 0; i < nr_objects; i++) {
+ unpack_one(i);
+ display_progress(progress, i + 1);
+ }
+ end_odb_transaction();
+ stop_progress(&progress);
+
+ if (delta_list)
+ die("unresolved deltas left after unpacking");
+}
+
+int cmd_unpack_objects(int argc, const char **argv, const char *prefix UNUSED)
+{
+ int i;
+ struct object_id oid;
+ git_hash_ctx tmp_ctx;
+
+ disable_replace_refs();
+
+ git_config(git_default_config, NULL);
+
+ quiet = !isatty(2);
+
+ for (i = 1 ; i < argc; i++) {
+ const char *arg = argv[i];
+
+ if (*arg == '-') {
+ if (!strcmp(arg, "-n")) {
+ dry_run = 1;
+ continue;
+ }
+ if (!strcmp(arg, "-q")) {
+ quiet = 1;
+ continue;
+ }
+ if (!strcmp(arg, "-r")) {
+ recover = 1;
+ continue;
+ }
+ if (!strcmp(arg, "--strict")) {
+ strict = 1;
+ continue;
+ }
+ if (skip_prefix(arg, "--strict=", &arg)) {
+ strict = 1;
+ fsck_set_msg_types(&fsck_options, arg);
+ continue;
+ }
+ if (starts_with(arg, "--pack_header=")) {
+ struct pack_header *hdr;
+ char *c;
+
+ hdr = (struct pack_header *)buffer;
+ hdr->hdr_signature = htonl(PACK_SIGNATURE);
+ hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
+ if (*c != ',')
+ die("bad %s", arg);
+ hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
+ if (*c)
+ die("bad %s", arg);
+ len = sizeof(*hdr);
+ continue;
+ }
+ if (skip_prefix(arg, "--max-input-size=", &arg)) {
+ max_input_size = strtoumax(arg, NULL, 10);
+ continue;
+ }
+ usage(unpack_usage);
+ }
+
+ /* We don't take any non-flag arguments now.. Maybe some day */
+ usage(unpack_usage);
+ }
+ the_hash_algo->init_fn(&ctx);
+ unpack_all();
+ the_hash_algo->update_fn(&ctx, buffer, offset);
+ the_hash_algo->init_fn(&tmp_ctx);
+ the_hash_algo->clone_fn(&tmp_ctx, &ctx);
+ the_hash_algo->final_oid_fn(&oid, &tmp_ctx);
+ if (strict) {
+ write_rest();
+ if (fsck_finish(&fsck_options))
+ die(_("fsck error in pack objects"));
+ }
+ if (!hasheq(fill(the_hash_algo->rawsz), oid.hash))
+ die("final sha1 did not match");
+ use(the_hash_algo->rawsz);
+
+ /* Write the last part of the buffer to stdout */
+ while (len) {
+ int ret = xwrite(1, buffer + offset, len);
+ if (ret <= 0)
+ break;
+ len -= ret;
+ offset += ret;
+ }
+
+ /* All done */
+ return has_errors;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 16:15:39 +0000