perf build-id: Add quirk to deal with perf.data file format breakage

	return err;

}

static int perf_header__read_build_ids(struct perf_header *header,

static int perf_header__read_build_ids_abi_quirk(struct perf_header *header,

						 int input, u64 offset, u64 size)

{

	struct perf_session *session = container_of(header, struct perf_session, header);

	struct {

		struct perf_event_header   header;

		u8			   build_id[ALIGN(BUILD_ID_SIZE, sizeof(u64))];

		char			   filename[0];

	} old_bev;

	struct build_id_event bev;

	char filename[PATH_MAX];

	u64 limit = offset + size;

	while (offset < limit) {

		ssize_t len;

		if (read(input, &old_bev, sizeof(old_bev)) != sizeof(old_bev))

			return -1;

		if (header->needs_swap)

			perf_event_header__bswap(&old_bev.header);

		len = old_bev.header.size - sizeof(old_bev);

		if (read(input, filename, len) != len)

			return -1;

		bev.header = old_bev.header;

		bev.pid	   = 0;

		memcpy(bev.build_id, old_bev.build_id, sizeof(bev.build_id));

		__event_process_build_id(&bev, filename, session);

		offset += bev.header.size;

	}

	return 0;

}

static int perf_header__read_build_ids(struct perf_header *header,

				       int input, u64 offset, u64 size)

{

	struct perf_session *session = container_of(header, struct perf_session, header);

	struct build_id_event bev;

	char filename[PATH_MAX];

	u64 limit = offset + size, orig_offset = offset;

	int err = -1;

	while (offset < limit) {

		len = bev.header.size - sizeof(bev);

		if (read(input, filename, len) != len)

			goto out;

		/*

		 * The a1645ce1 changeset:

		 *

		 * "perf: 'perf kvm' tool for monitoring guest performance from host"

		 *

		 * Added a field to struct build_id_event that broke the file

		 * format.

		 *

		 * Since the kernel build-id is the first entry, process the

		 * table using the old format if the well known

		 * '[kernel.kallsyms]' string for the kernel build-id has the

		 * first 4 characters chopped off (where the pid_t sits).

		 */

		if (memcmp(filename, "nel.kallsyms]", 13) == 0) {

			if (lseek(input, orig_offset, SEEK_SET) == (off_t)-1)

				return -1;

			return perf_header__read_build_ids_abi_quirk(header, input, offset, size);

		}

		__event_process_build_id(&bev, filename, session);