1 files changed, 238 insertions, 44 deletions

diff --git a/pack-write.c b/pack-write.c
index e59b197e5e..ca9e63be18 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -2,8 +2,12 @@
 #include "pack.h"
 #include "csum-file.h"
 
-uint32_t pack_idx_default_version = 1;
-uint32_t pack_idx_off32_limit = 0x7fffffff;
+void reset_pack_idx_option(struct pack_idx_option *opts)
+{
+	memset(opts, 0, sizeof(*opts));
+	opts->version = 2;
+	opts->off32_limit = 0x7fffffff;
+}
 
 static int sha1_compare(const void *_a, const void *_b)
 {
@@ -12,19 +16,42 @@ static int sha1_compare(const void *_a, const void *_b)
 	return hashcmp(a->sha1, b->sha1);
 }
 
+static int cmp_uint32(const void *a_, const void *b_)
+{
+	uint32_t a = *((uint32_t *)a_);
+	uint32_t b = *((uint32_t *)b_);
+
+	return (a < b) ? -1 : (a != b);
+}
+
+static int need_large_offset(off_t offset, const struct pack_idx_option *opts)
+{
+	uint32_t ofsval;
+
+	if ((offset >> 31) || (opts->off32_limit < offset))
+		return 1;
+	if (!opts->anomaly_nr)
+		return 0;
+	ofsval = offset;
+	return !!bsearch(&ofsval, opts->anomaly, opts->anomaly_nr,
+			 sizeof(ofsval), cmp_uint32);
+}
+
 /*
  * On entry *sha1 contains the pack content SHA1 hash, on exit it is
  * the SHA1 hash of sorted object names. The objects array passed in
  * will be sorted by SHA1 on exit.
  */
-const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, unsigned char *sha1)
+const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects,
+			   int nr_objects, const struct pack_idx_option *opts,
+			   unsigned char *sha1)
 {
 	struct sha1file *f;
 	struct pack_idx_entry **sorted_by_sha, **list, **last;
 	off_t last_obj_offset = 0;
 	uint32_t array[256];
 	int i, fd;
-	SHA_CTX ctx;
+	git_SHA_CTX ctx;
 	uint32_t index_version;
 
 	if (nr_objects) {
@@ -41,22 +68,25 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec
 	else
 		sorted_by_sha = list = last = NULL;
 
-	if (!index_name) {
-		static char tmpfile[PATH_MAX];
-		snprintf(tmpfile, sizeof(tmpfile),
-			 "%s/tmp_idx_XXXXXX", get_object_directory());
-		fd = xmkstemp(tmpfile);
-		index_name = xstrdup(tmpfile);
+	if (opts->flags & WRITE_IDX_VERIFY) {
+		assert(index_name);
+		f = sha1fd_check(index_name);
 	} else {
-		unlink(index_name);
-		fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
+		if (!index_name) {
+			static char tmp_file[PATH_MAX];
+			fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_idx_XXXXXX");
+			index_name = xstrdup(tmp_file);
+		} else {
+			unlink(index_name);
+			fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
+		}
+		if (fd < 0)
+			die_errno("unable to create '%s'", index_name);
+		f = sha1fd(fd, index_name);
 	}
-	if (fd < 0)
-		die("unable to create %s: %s", index_name, strerror(errno));
-	f = sha1fd(fd, index_name);
 
 	/* if last object's offset is >= 2^31 we should use index V2 */
-	index_version = (last_obj_offset >> 31) ? 2 : pack_idx_default_version;
+	index_version = need_large_offset(last_obj_offset, opts) ? 2 : opts->version;
 
 	/* index versions 2 and above need a header */
 	if (index_version >= 2) {
@@ -85,7 +115,7 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec
 	sha1write(f, array, 256 * 4);
 
 	/* compute the SHA1 hash of sorted object names. */
-	SHA1_Init(&ctx);
+	git_SHA1_Init(&ctx);
 
 	/*
 	 * Write the actual SHA1 entries..
@@ -98,7 +128,11 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec
 			sha1write(f, &offset, 4);
 		}
 		sha1write(f, obj->sha1, 20);
-		SHA1_Update(&ctx, obj->sha1, 20);
+		git_SHA1_Update(&ctx, obj->sha1, 20);
+		if ((opts->flags & WRITE_IDX_STRICT) &&
+		    (i && !hashcmp(list[-2]->sha1, obj->sha1)))
+			die("The same object %s appears twice in the pack",
+			    sha1_to_hex(obj->sha1));
 	}
 
 	if (index_version >= 2) {
@@ -116,8 +150,11 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec
 		list = sorted_by_sha;
 		for (i = 0; i < nr_objects; i++) {
 			struct pack_idx_entry *obj = *list++;
-			uint32_t offset = (obj->offset <= pack_idx_off32_limit) ?
-				obj->offset : (0x80000000 | nr_large_offset++);
+			uint32_t offset;
+
+			offset = (need_large_offset(obj->offset, opts)
+				  ? (0x80000000 | nr_large_offset++)
+				  : obj->offset);
 			offset = htonl(offset);
 			sha1write(f, &offset, 4);
 		}
@@ -127,55 +164,212 @@ const char *write_idx_file(const char *index_name, struct pack_idx_entry **objec
 		while (nr_large_offset) {
 			struct pack_idx_entry *obj = *list++;
 			uint64_t offset = obj->offset;
-			if (offset > pack_idx_off32_limit) {
-				uint32_t split[2];
-				split[0] = htonl(offset >> 32);
-				split[1] = htonl(offset & 0xffffffff);
-				sha1write(f, split, 8);
-				nr_large_offset--;
-			}
+			uint32_t split[2];
+
+			if (!need_large_offset(offset, opts))
+				continue;
+			split[0] = htonl(offset >> 32);
+			split[1] = htonl(offset & 0xffffffff);
+			sha1write(f, split, 8);
+			nr_large_offset--;
 		}
 	}
 
 	sha1write(f, sha1, 20);
-	sha1close(f, NULL, 1);
-	SHA1_Final(sha1, &ctx);
+	sha1close(f, NULL, ((opts->flags & WRITE_IDX_VERIFY)
+			    ? CSUM_CLOSE : CSUM_FSYNC));
+	git_SHA1_Final(sha1, &ctx);
 	return index_name;
 }
 
+off_t write_pack_header(struct sha1file *f, uint32_t nr_entries)
+{
+	struct pack_header hdr;
+
+	hdr.hdr_signature = htonl(PACK_SIGNATURE);
+	hdr.hdr_version = htonl(PACK_VERSION);
+	hdr.hdr_entries = htonl(nr_entries);
+	if (sha1write(f, &hdr, sizeof(hdr)))
+		return 0;
+	return sizeof(hdr);
+}
+
+/*
+ * Update pack header with object_count and compute new SHA1 for pack data
+ * associated to pack_fd, and write that SHA1 at the end.  That new SHA1
+ * is also returned in new_pack_sha1.
+ *
+ * If partial_pack_sha1 is non null, then the SHA1 of the existing pack
+ * (without the header update) is computed and validated against the
+ * one provided in partial_pack_sha1.  The validation is performed at
+ * partial_pack_offset bytes in the pack file.  The SHA1 of the remaining
+ * data (i.e. from partial_pack_offset to the end) is then computed and
+ * returned in partial_pack_sha1.
+ *
+ * Note that new_pack_sha1 is updated last, so both new_pack_sha1 and
+ * partial_pack_sha1 can refer to the same buffer if the caller is not
+ * interested in the resulting SHA1 of pack data above partial_pack_offset.
+ */
 void fixup_pack_header_footer(int pack_fd,
-			 unsigned char *pack_file_sha1,
+			 unsigned char *new_pack_sha1,
 			 const char *pack_name,
-			 uint32_t object_count)
+			 uint32_t object_count,
+			 unsigned char *partial_pack_sha1,
+			 off_t partial_pack_offset)
 {
-	static const int buf_sz = 128 * 1024;
-	SHA_CTX c;
+	int aligned_sz, buf_sz = 8 * 1024;
+	git_SHA_CTX old_sha1_ctx, new_sha1_ctx;
 	struct pack_header hdr;
 	char *buf;
 
+	git_SHA1_Init(&old_sha1_ctx);
+	git_SHA1_Init(&new_sha1_ctx);
+
 	if (lseek(pack_fd, 0, SEEK_SET) != 0)
-		die("Failed seeking to start: %s", strerror(errno));
+		die_errno("Failed seeking to start of '%s'", pack_name);
 	if (read_in_full(pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
-		die("Unable to reread header of %s: %s", pack_name, strerror(errno));
+		die_errno("Unable to reread header of '%s'", pack_name);
 	if (lseek(pack_fd, 0, SEEK_SET) != 0)
-		die("Failed seeking to start: %s", strerror(errno));
+		die_errno("Failed seeking to start of '%s'", pack_name);
+	git_SHA1_Update(&old_sha1_ctx, &hdr, sizeof(hdr));
 	hdr.hdr_entries = htonl(object_count);
+	git_SHA1_Update(&new_sha1_ctx, &hdr, sizeof(hdr));
 	write_or_die(pack_fd, &hdr, sizeof(hdr));
-
-	SHA1_Init(&c);
-	SHA1_Update(&c, &hdr, sizeof(hdr));
+	partial_pack_offset -= sizeof(hdr);
 
 	buf = xmalloc(buf_sz);
+	aligned_sz = buf_sz - sizeof(hdr);
 	for (;;) {
-		ssize_t n = xread(pack_fd, buf, buf_sz);
+		ssize_t m, n;
+		m = (partial_pack_sha1 && partial_pack_offset < aligned_sz) ?
+			partial_pack_offset : aligned_sz;
+		n = xread(pack_fd, buf, m);
 		if (!n)
 			break;
 		if (n < 0)
-			die("Failed to checksum %s: %s", pack_name, strerror(errno));
-		SHA1_Update(&c, buf, n);
+			die_errno("Failed to checksum '%s'", pack_name);
+		git_SHA1_Update(&new_sha1_ctx, buf, n);
+
+		aligned_sz -= n;
+		if (!aligned_sz)
+			aligned_sz = buf_sz;
+
+		if (!partial_pack_sha1)
+			continue;
+
+		git_SHA1_Update(&old_sha1_ctx, buf, n);
+		partial_pack_offset -= n;
+		if (partial_pack_offset == 0) {
+			unsigned char sha1[20];
+			git_SHA1_Final(sha1, &old_sha1_ctx);
+			if (hashcmp(sha1, partial_pack_sha1) != 0)
+				die("Unexpected checksum for %s "
+				    "(disk corruption?)", pack_name);
+			/*
+			 * Now let's compute the SHA1 of the remainder of the
+			 * pack, which also means making partial_pack_offset
+			 * big enough not to matter anymore.
+			 */
+			git_SHA1_Init(&old_sha1_ctx);
+			partial_pack_offset = ~partial_pack_offset;
+			partial_pack_offset -= MSB(partial_pack_offset, 1);
+		}
 	}
 	free(buf);
 
-	SHA1_Final(pack_file_sha1, &c);
-	write_or_die(pack_fd, pack_file_sha1, 20);
+	if (partial_pack_sha1)
+		git_SHA1_Final(partial_pack_sha1, &old_sha1_ctx);
+	git_SHA1_Final(new_pack_sha1, &new_sha1_ctx);
+	write_or_die(pack_fd, new_pack_sha1, 20);
+	fsync_or_die(pack_fd, pack_name);
+}
+
+char *index_pack_lockfile(int ip_out)
+{
+	char packname[46];
+
+	/*
+	 * The first thing we expect from index-pack's output
+	 * is "pack\t%40s\n" or "keep\t%40s\n" (46 bytes) where
+	 * %40s is the newly created pack SHA1 name.  In the "keep"
+	 * case, we need it to remove the corresponding .keep file
+	 * later on.  If we don't get that then tough luck with it.
+	 */
+	if (read_in_full(ip_out, packname, 46) == 46 && packname[45] == '\n' &&
+	    memcmp(packname, "keep\t", 5) == 0) {
+		char path[PATH_MAX];
+		packname[45] = 0;
+		snprintf(path, sizeof(path), "%s/pack/pack-%s.keep",
+			 get_object_directory(), packname + 5);
+		return xstrdup(path);
+	}
+	return NULL;
+}
+
+/*
+ * The per-object header is a pretty dense thing, which is
+ *  - first byte: low four bits are "size", then three bits of "type",
+ *    and the high bit is "size continues".
+ *  - each byte afterwards: low seven bits are size continuation,
+ *    with the high bit being "size continues"
+ */
+int encode_in_pack_object_header(enum object_type type, uintmax_t size, unsigned char *hdr)
+{
+	int n = 1;
+	unsigned char c;
+
+	if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
+		die("bad type %d", type);
+
+	c = (type << 4) | (size & 15);
+	size >>= 4;
+	while (size) {
+		*hdr++ = c | 0x80;
+		c = size & 0x7f;
+		size >>= 7;
+		n++;
+	}
+	*hdr = c;
+	return n;
+}
+
+struct sha1file *create_tmp_packfile(char **pack_tmp_name)
+{
+	char tmpname[PATH_MAX];
+	int fd;
+
+	fd = odb_mkstemp(tmpname, sizeof(tmpname), "pack/tmp_pack_XXXXXX");
+	*pack_tmp_name = xstrdup(tmpname);
+	return sha1fd(fd, *pack_tmp_name);
+}
+
+void finish_tmp_packfile(char *name_buffer,
+			 const char *pack_tmp_name,
+			 struct pack_idx_entry **written_list,
+			 uint32_t nr_written,
+			 struct pack_idx_option *pack_idx_opts,
+			 unsigned char sha1[])
+{
+	const char *idx_tmp_name;
+	char *end_of_name_prefix = strrchr(name_buffer, 0);
+
+	if (adjust_shared_perm(pack_tmp_name))
+		die_errno("unable to make temporary pack file readable");
+
+	idx_tmp_name = write_idx_file(NULL, written_list, nr_written,
+				      pack_idx_opts, sha1);
+	if (adjust_shared_perm(idx_tmp_name))
+		die_errno("unable to make temporary index file readable");
+
+	sprintf(end_of_name_prefix, "%s.pack", sha1_to_hex(sha1));
+	free_pack_by_name(name_buffer);
+
+	if (rename(pack_tmp_name, name_buffer))
+		die_errno("unable to rename temporary pack file");
+
+	sprintf(end_of_name_prefix, "%s.idx", sha1_to_hex(sha1));
+	if (rename(idx_tmp_name, name_buffer))
+		die_errno("unable to rename temporary index file");
+
+	free((void *)idx_tmp_name);
 }