Squashed 'third_party/git/' content from commit cb71568594

git-subtree-dir: third_party/git
git-subtree-split: cb715685942260375e1eb8153b0768a376e4ece7

1 files changed, 204 insertions, 0 deletions

diff --git a/pack-check.c b/pack-check.c
new file mode 100644
index 0000000000..2cc3603189
--- /dev/null
+++ b/pack-check.c
@@ -0,0 +1,204 @@
+#include "cache.h"
+#include "repository.h"
+#include "pack.h"
+#include "pack-revindex.h"
+#include "progress.h"
+#include "packfile.h"
+#include "object-store.h"
+
+struct idx_entry {
+	off_t                offset;
+	union idx_entry_object {
+		const unsigned char *hash;
+		struct object_id *oid;
+	} oid;
+	unsigned int nr;
+};
+
+static int compare_entries(const void *e1, const void *e2)
+{
+	const struct idx_entry *entry1 = e1;
+	const struct idx_entry *entry2 = e2;
+	if (entry1->offset < entry2->offset)
+		return -1;
+	if (entry1->offset > entry2->offset)
+		return 1;
+	return 0;
+}
+
+int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
+		   off_t offset, off_t len, unsigned int nr)
+{
+	const uint32_t *index_crc;
+	uint32_t data_crc = crc32(0, NULL, 0);
+
+	do {
+		unsigned long avail;
+		void *data = use_pack(p, w_curs, offset, &avail);
+		if (avail > len)
+			avail = len;
+		data_crc = crc32(data_crc, data, avail);
+		offset += avail;
+		len -= avail;
+	} while (len);
+
+	index_crc = p->index_data;
+	index_crc += 2 + 256 + p->num_objects * (the_hash_algo->rawsz/4) + nr;
+
+	return data_crc != ntohl(*index_crc);
+}
+
+static int verify_packfile(struct repository *r,
+			   struct packed_git *p,
+			   struct pack_window **w_curs,
+			   verify_fn fn,
+			   struct progress *progress, uint32_t base_count)
+
+{
+	off_t index_size = p->index_size;
+	const unsigned char *index_base = p->index_data;
+	git_hash_ctx ctx;
+	unsigned char hash[GIT_MAX_RAWSZ], *pack_sig;
+	off_t offset = 0, pack_sig_ofs = 0;
+	uint32_t nr_objects, i;
+	int err = 0;
+	struct idx_entry *entries;
+
+	if (!is_pack_valid(p))
+		return error("packfile %s cannot be accessed", p->pack_name);
+
+	the_hash_algo->init_fn(&ctx);
+	do {
+		unsigned long remaining;
+		unsigned char *in = use_pack(p, w_curs, offset, &remaining);
+		offset += remaining;
+		if (!pack_sig_ofs)
+			pack_sig_ofs = p->pack_size - the_hash_algo->rawsz;
+		if (offset > pack_sig_ofs)
+			remaining -= (unsigned int)(offset - pack_sig_ofs);
+		the_hash_algo->update_fn(&ctx, in, remaining);
+	} while (offset < pack_sig_ofs);
+	the_hash_algo->final_fn(hash, &ctx);
+	pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
+	if (!hasheq(hash, pack_sig))
+		err = error("%s pack checksum mismatch",
+			    p->pack_name);
+	if (!hasheq(index_base + index_size - the_hash_algo->hexsz, pack_sig))
+		err = error("%s pack checksum does not match its index",
+			    p->pack_name);
+	unuse_pack(w_curs);
+
+	/* Make sure everything reachable from idx is valid.  Since we
+	 * have verified that nr_objects matches between idx and pack,
+	 * we do not do scan-streaming check on the pack file.
+	 */
+	nr_objects = p->num_objects;
+	ALLOC_ARRAY(entries, nr_objects + 1);
+	entries[nr_objects].offset = pack_sig_ofs;
+	/* first sort entries by pack offset, since unpacking them is more efficient that way */
+	for (i = 0; i < nr_objects; i++) {
+		entries[i].oid.hash = nth_packed_object_sha1(p, i);
+		if (!entries[i].oid.hash)
+			die("internal error pack-check nth-packed-object");
+		entries[i].offset = nth_packed_object_offset(p, i);
+		entries[i].nr = i;
+	}
+	QSORT(entries, nr_objects, compare_entries);
+
+	for (i = 0; i < nr_objects; i++) {
+		void *data;
+		enum object_type type;
+		unsigned long size;
+		off_t curpos;
+		int data_valid;
+
+		if (p->index_version > 1) {
+			off_t offset = entries[i].offset;
+			off_t len = entries[i+1].offset - offset;
+			unsigned int nr = entries[i].nr;
+			if (check_pack_crc(p, w_curs, offset, len, nr))
+				err = error("index CRC mismatch for object %s "
+					    "from %s at offset %"PRIuMAX"",
+					    oid_to_hex(entries[i].oid.oid),
+					    p->pack_name, (uintmax_t)offset);
+		}
+
+		curpos = entries[i].offset;
+		type = unpack_object_header(p, w_curs, &curpos, &size);
+		unuse_pack(w_curs);
+
+		if (type == OBJ_BLOB && big_file_threshold <= size) {
+			/*
+			 * Let check_object_signature() check it with
+			 * the streaming interface; no point slurping
+			 * the data in-core only to discard.
+			 */
+			data = NULL;
+			data_valid = 0;
+		} else {
+			data = unpack_entry(r, p, entries[i].offset, &type, &size);
+			data_valid = 1;
+		}
+
+		if (data_valid && !data)
+			err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
+				    oid_to_hex(entries[i].oid.oid), p->pack_name,
+				    (uintmax_t)entries[i].offset);
+		else if (check_object_signature(entries[i].oid.oid, data, size, type_name(type)))
+			err = error("packed %s from %s is corrupt",
+				    oid_to_hex(entries[i].oid.oid), p->pack_name);
+		else if (fn) {
+			int eaten = 0;
+			err |= fn(entries[i].oid.oid, type, size, data, &eaten);
+			if (eaten)
+				data = NULL;
+		}
+		if (((base_count + i) & 1023) == 0)
+			display_progress(progress, base_count + i);
+		free(data);
+
+	}
+	display_progress(progress, base_count + i);
+	free(entries);
+
+	return err;
+}
+
+int verify_pack_index(struct packed_git *p)
+{
+	off_t index_size;
+	const unsigned char *index_base;
+	git_hash_ctx ctx;
+	unsigned char hash[GIT_MAX_RAWSZ];
+	int err = 0;
+
+	if (open_pack_index(p))
+		return error("packfile %s index not opened", p->pack_name);
+	index_size = p->index_size;
+	index_base = p->index_data;
+
+	/* Verify SHA1 sum of the index file */
+	the_hash_algo->init_fn(&ctx);
+	the_hash_algo->update_fn(&ctx, index_base, (unsigned int)(index_size - the_hash_algo->rawsz));
+	the_hash_algo->final_fn(hash, &ctx);
+	if (!hasheq(hash, index_base + index_size - the_hash_algo->rawsz))
+		err = error("Packfile index for %s hash mismatch",
+			    p->pack_name);
+	return err;
+}
+
+int verify_pack(struct repository *r, struct packed_git *p, verify_fn fn,
+		struct progress *progress, uint32_t base_count)
+{
+	int err = 0;
+	struct pack_window *w_curs = NULL;
+
+	err |= verify_pack_index(p);
+	if (!p->index_data)
+		return -1;
+
+	err |= verify_packfile(r, p, &w_curs, fn, progress, base_count);
+	unuse_pack(&w_curs);
+
+	return err;
+}