Function sendFileWithContent

src/backend/replication/basebackup.c:1256–1313

* Inject a file with given name and content in the output tar stream. */

 * Inject a file with given name and content in the output tar stream.
 */
static void
sendFileWithContent(const char *filename, const char *content,
					backup_manifest_info *manifest)
{
	struct stat statbuf;
	int			pad,
				len;
	pg_checksum_context checksum_ctx;

	if (pg_checksum_init(&checksum_ctx, manifest->checksum_type) < 0)
		elog(ERROR, "could not initialize checksum of file \"%s\"",
			 filename);

	len = strlen(content);

	/*
	 * Construct a stat struct for the backup_label file we're injecting in
	 * the tar.
	 */
	/* Windows doesn't have the concept of uid and gid */
#ifdef WIN32
	statbuf.st_uid = 0;
	statbuf.st_gid = 0;
#else
	statbuf.st_uid = geteuid();
	statbuf.st_gid = getegid();
#endif
	statbuf.st_mtime = time(NULL);
	statbuf.st_mode = pg_file_create_mode;
	statbuf.st_size = len;

	_tarWriteHeader(filename, NULL, &statbuf, false);
	/* Send the contents as a CopyData message */
	pq_putmessage('d', content, len);
	update_basebackup_progress(len);

	/* Pad to a multiple of the tar block size. */
	pad = tarPaddingBytesRequired(len);
	if (pad > 0)
	{
		char		buf[TAR_BLOCK_SIZE];

		MemSet(buf, 0, pad);
		pq_putmessage('d', buf, pad);
		update_basebackup_progress(pad);
	}

	elogif(debug_basebackup, LOG,
			"basebackup send file -- Sent file '%s' with content \n%s.",
			filename, content);

	if (pg_checksum_update(&checksum_ctx, (uint8 *) content, len) < 0)
		elog(ERROR, "could not update checksum of file \"%s\"",
			 filename);

	AddFileToBackupManifest(manifest, NULL, filename, len,
							(pg_time_t) statbuf.st_mtime, &checksum_ctx);
}