Adding upstream version 3.2.7.upstream/3.2.7

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 887 insertions, 0 deletions

diff --git a/compat.c b/compat.c
new file mode 100644
index 0000000..a8a6afe
--- /dev/null
+++ b/compat.c
@@ -0,0 +1,887 @@
+/*
+ * Compatibility routines for older rsync protocol versions.
+ *
+ * Copyright (C) Andrew Tridgell 1996
+ * Copyright (C) Paul Mackerras 1996
+ * Copyright (C) 2004-2022 Wayne Davison
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, visit the http://fsf.org website.
+ */
+
+#include "rsync.h"
+#include "itypes.h"
+#include "ifuncs.h"
+
+extern int am_server;
+extern int am_sender;
+extern int local_server;
+extern int inplace;
+extern int recurse;
+extern int use_qsort;
+extern int allow_inc_recurse;
+extern int preallocate_files;
+extern int append_mode;
+extern int fuzzy_basis;
+extern int read_batch;
+extern int write_batch;
+extern int delay_updates;
+extern int checksum_seed;
+extern int basis_dir_cnt;
+extern int prune_empty_dirs;
+extern int protocol_version;
+extern int protect_args;
+extern int preserve_uid;
+extern int preserve_gid;
+extern int preserve_atimes;
+extern int preserve_crtimes;
+extern int preserve_acls;
+extern int preserve_xattrs;
+extern int xfer_flags_as_varint;
+extern int need_messages_from_generator;
+extern int delete_mode, delete_before, delete_during, delete_after;
+extern int do_compression;
+extern int do_compression_level;
+extern int saw_stderr_opt;
+extern int msgs2stderr;
+extern char *shell_cmd;
+extern char *partial_dir;
+extern char *files_from;
+extern char *filesfrom_host;
+extern const char *checksum_choice;
+extern const char *compress_choice;
+extern char *daemon_auth_choices;
+extern filter_rule_list filter_list;
+extern int need_unsorted_flist;
+#ifdef ICONV_OPTION
+extern iconv_t ic_send, ic_recv;
+extern char *iconv_opt;
+#endif
+extern struct name_num_obj valid_checksums, valid_auth_checksums;
+
+extern struct name_num_item *xfer_sum_nni;
+
+int remote_protocol = 0;
+int file_extra_cnt = 0; /* count of file-list extras that everyone gets */
+int inc_recurse = 0;
+int compat_flags = 0;
+int use_safe_inc_flist = 0;
+int want_xattr_optim = 0;
+int proper_seed_order = 0;
+int inplace_partial = 0;
+int do_negotiated_strings = 0;
+int xmit_id0_names = 0;
+
+struct name_num_item *xattr_sum_nni;
+int xattr_sum_len = 0;
+
+/* These index values are for the file-list's extra-attribute array. */
+int pathname_ndx, depth_ndx, atimes_ndx, crtimes_ndx, uid_ndx, gid_ndx, acls_ndx, xattrs_ndx, unsort_ndx;
+
+int receiver_symlink_times = 0; /* receiver can set the time on a symlink */
+int sender_symlink_iconv = 0;	/* sender should convert symlink content */
+
+#ifdef ICONV_OPTION
+int filesfrom_convert = 0;
+#endif
+
+#define MAX_NSTR_STRLEN 256
+
+struct name_num_item valid_compressions_items[] = {
+#ifdef SUPPORT_ZSTD
+	{ CPRES_ZSTD, 0, "zstd", NULL },
+#endif
+#ifdef SUPPORT_LZ4
+	{ CPRES_LZ4, 0, "lz4", NULL },
+#endif
+	{ CPRES_ZLIBX, 0, "zlibx", NULL },
+	{ CPRES_ZLIB, 0, "zlib", NULL },
+	{ CPRES_NONE, 0, "none", NULL },
+	{ 0, 0, NULL, NULL }
+};
+
+struct name_num_obj valid_compressions = {
+	"compress", NULL, 0, 0, valid_compressions_items
+};
+
+#define CF_INC_RECURSE	 (1<<0)
+#define CF_SYMLINK_TIMES (1<<1)
+#define CF_SYMLINK_ICONV (1<<2)
+#define CF_SAFE_FLIST	 (1<<3)
+#define CF_AVOID_XATTR_OPTIM (1<<4)
+#define CF_CHKSUM_SEED_FIX (1<<5)
+#define CF_INPLACE_PARTIAL_DIR (1<<6)
+#define CF_VARINT_FLIST_FLAGS (1<<7)
+#define CF_ID0_NAMES (1<<8)
+
+static const char *client_info;
+
+/* The server makes sure that if either side only supports a pre-release
+ * version of a protocol, that both sides must speak a compatible version
+ * of that protocol for it to be advertised as available. */
+static void check_sub_protocol(void)
+{
+	char *dot;
+	int their_protocol, their_sub;
+	int our_sub = get_subprotocol_version();
+
+	/* client_info starts with VER.SUB string if client is a pre-release. */
+	if (!(their_protocol = atoi(client_info))
+	 || !(dot = strchr(client_info, '.'))
+	 || !(their_sub = atoi(dot+1))) {
+#if SUBPROTOCOL_VERSION != 0
+		if (our_sub)
+			protocol_version--;
+#endif
+		return;
+	}
+
+	if (their_protocol < protocol_version) {
+		if (their_sub)
+			protocol_version = their_protocol - 1;
+		return;
+	}
+
+	if (their_protocol > protocol_version)
+		their_sub = 0; /* 0 == final version of older protocol */
+	if (their_sub != our_sub)
+		protocol_version--;
+}
+
+void set_allow_inc_recurse(void)
+{
+	if (!local_server)
+		client_info = shell_cmd ? shell_cmd : "";
+	else if (am_server) {
+		char buf[64];
+		maybe_add_e_option(buf, sizeof buf);
+		client_info = *buf ? strdup(buf+1) : ""; /* The +1 skips the leading "e". */
+	}
+
+	if (!recurse || use_qsort)
+		allow_inc_recurse = 0;
+	else if (!am_sender
+	 && (delete_before || delete_after
+	  || delay_updates || prune_empty_dirs))
+		allow_inc_recurse = 0;
+	else if (am_server && strchr(client_info, 'i') == NULL)
+		allow_inc_recurse = 0;
+}
+
+void parse_compress_choice(int final_call)
+{
+	if (valid_compressions.negotiated_nni)
+		do_compression = valid_compressions.negotiated_nni->num;
+	else if (compress_choice) {
+		struct name_num_item *nni = get_nni_by_name(&valid_compressions, compress_choice, -1);
+		if (!nni) {
+			rprintf(FERROR, "unknown compress name: %s\n", compress_choice);
+			exit_cleanup(RERR_UNSUPPORTED);
+		}
+		do_compression = nni->num;
+		if (am_server)
+			validate_choice_vs_env(NSTR_COMPRESS, do_compression, -1);
+	} else if (do_compression)
+		do_compression = CPRES_ZLIB;
+	else
+		do_compression = CPRES_NONE;
+
+	if (do_compression != CPRES_NONE && final_call)
+		init_compression_level(); /* There's a chance this might turn compression off! */
+
+	if (do_compression == CPRES_NONE)
+		compress_choice = NULL;
+
+	/* Snag the compression name for both write_batch's option output & the following debug output. */
+	if (valid_compressions.negotiated_nni)
+		compress_choice = valid_compressions.negotiated_nni->name;
+	else if (compress_choice == NULL) {
+		struct name_num_item *nni = get_nni_by_num(&valid_compressions, do_compression);
+		compress_choice = nni ? nni->name : "UNKNOWN";
+	}
+
+	if (final_call && DEBUG_GTE(NSTR, am_server ? 3 : 1)
+	 && (do_compression != CPRES_NONE || do_compression_level != CLVL_NOT_SPECIFIED)) {
+		rprintf(FINFO, "%s%s compress: %s (level %d)\n",
+			am_server ? "Server" : "Client",
+			valid_compressions.negotiated_nni ? " negotiated" : "",
+			compress_choice, do_compression_level);
+	}
+}
+
+struct name_num_item *get_nni_by_name(struct name_num_obj *nno, const char *name, int len)
+{
+	struct name_num_item *nni;
+
+	if (len < 0)
+		len = strlen(name);
+
+	for (nni = nno->list; nni->name; nni++) {
+		if (nni->num == CSUM_gone)
+			continue;
+		if (strncasecmp(name, nni->name, len) == 0 && nni->name[len] == '\0')
+			return nni;
+	}
+
+	return NULL;
+}
+
+struct name_num_item *get_nni_by_num(struct name_num_obj *nno, int num)
+{
+	struct name_num_item *nni;
+
+	for (nni = nno->list; nni->name; nni++) {
+		if (num == nni->num)
+			return nni;
+	}
+
+	return NULL;
+}
+
+static void init_nno_saw(struct name_num_obj *nno, int val)
+{
+	struct name_num_item *nni;
+	int cnt;
+
+	if (!nno->saw_len) {
+		for (nni = nno->list; nni->name; nni++) {
+			if (nni->num >= nno->saw_len)
+				nno->saw_len = nni->num + 1;
+		}
+	}
+
+	if (!nno->saw) {
+		nno->saw = new_array0(uchar, nno->saw_len);
+
+		/* We'll take this opportunity to set the main_nni values for duplicates. */
+		for (cnt = 1, nni = nno->list; nni->name; nni++, cnt++) {
+			if (nni->num == CSUM_gone)
+				continue;
+			if (nno->saw[nni->num])
+				nni->main_nni = &nno->list[nno->saw[nni->num]-1];
+			else
+				nno->saw[nni->num] = cnt;
+		}
+	}
+
+	memset(nno->saw, val, nno->saw_len);
+}
+
+/* Simplify the user-provided string so that it contains valid names without any duplicates.
+ * It also sets the "saw" flags to a 1-relative count of which name was seen first. */
+static int parse_nni_str(struct name_num_obj *nno, const char *from, char *tobuf, int tobuf_len)
+{
+	char *to = tobuf, *tok = NULL;
+	int saw_tok = 0, cnt = 0;
+
+	while (1) {
+		int at_space = isSpace(from);
+		char ch = *from++;
+		if (ch == '&')
+			ch = '\0';
+		if (!ch || at_space) {
+			if (tok) {
+				struct name_num_item *nni = get_nni_by_name(nno, tok, to - tok);
+				if (nni && !nno->saw[nni->num]) {
+					nno->saw[nni->num] = ++cnt;
+					if (nni->main_nni) {
+						to = tok + strlcpy(tok, nni->main_nni->name, tobuf_len - (tok - tobuf));
+						if (to - tobuf >= tobuf_len) {
+							to = tok - 1;
+							break;
+						}
+					}
+				} else
+					to = tok - (tok != tobuf);
+				saw_tok = 1;
+				tok = NULL;
+			}
+			if (!ch)
+				break;
+			continue;
+		}
+		if (!tok) {
+			if (to != tobuf)
+				*to++ = ' ';
+			tok = to;
+		}
+		if (to - tobuf >= tobuf_len - 1) {
+			to = tok - (tok != tobuf);
+			break;
+		}
+		*to++ = ch;
+	}
+	*to = '\0';
+
+	if (saw_tok && to == tobuf)
+		return strlcpy(tobuf, "INVALID", MAX_NSTR_STRLEN);
+
+	return to - tobuf;
+}
+
+static int parse_negotiate_str(struct name_num_obj *nno, char *tmpbuf)
+{
+	struct name_num_item *nni, *ret = NULL;
+	int best = nno->saw_len; /* We want best == 1 from the client list, so start with a big number. */
+	char *space, *tok = tmpbuf;
+	while (tok) {
+		while (*tok == ' ') tok++; /* Should be unneeded... */
+		if (!*tok)
+			break;
+		if ((space = strchr(tok, ' ')) != NULL)
+			*space = '\0';
+		nni = get_nni_by_name(nno, tok, -1);
+		if (space) {
+			*space = ' ';
+			tok = space + 1;
+		} else
+			tok = NULL;
+		if (!nni || !nno->saw[nni->num] || best <= nno->saw[nni->num])
+			continue;
+		ret = nni;
+		best = nno->saw[nni->num];
+		if (best == 1 || am_server) /* The server side stops at the first acceptable client choice */
+			break;
+	}
+	if (ret) {
+		free(nno->saw);
+		nno->saw = NULL;
+		nno->negotiated_nni = ret->main_nni ? ret->main_nni : ret;
+		return 1;
+	}
+	return 0;
+}
+
+/* This routine is always called with a tmpbuf of MAX_NSTR_STRLEN length, but the
+ * buffer may be pre-populated with a "len" length string to use OR a len of -1
+ * to tell us to read a string from the fd. */
+static void recv_negotiate_str(int f_in, struct name_num_obj *nno, char *tmpbuf, int len)
+{
+	if (len < 0)
+		len = read_vstring(f_in, tmpbuf, MAX_NSTR_STRLEN);
+
+	if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
+		if (am_server)
+			rprintf(FINFO, "Client %s list (on server): %s\n", nno->type, tmpbuf);
+		else
+			rprintf(FINFO, "Server %s list (on client): %s\n", nno->type, tmpbuf);
+	}
+
+	if (len > 0 && parse_negotiate_str(nno, tmpbuf))
+		return;
+
+	if (!am_server || !do_negotiated_strings) {
+		char *cp = tmpbuf;
+		int j;
+		rprintf(FERROR, "Failed to negotiate a %s choice.\n", nno->type);
+		rprintf(FERROR, "%s list: %s\n", am_server ? "Client" : "Server", tmpbuf);
+		/* Recreate our original list from the saw values. This can't overflow our huge
+		 * buffer because we don't have enough valid entries to get anywhere close. */
+		for (j = 1, *cp = '\0'; j <= nno->saw_len; j++) {
+			struct name_num_item *nni;
+			for (nni = nno->list; nni->name; nni++) {
+				if (nno->saw[nni->num] == j) {
+					*cp++ = ' ';
+					cp += strlcpy(cp, nni->name, MAX_NSTR_STRLEN - (cp - tmpbuf));
+					break;
+				}
+			}
+		}
+		if (!*tmpbuf)
+			strlcpy(cp, " INVALID", MAX_NSTR_STRLEN);
+		rprintf(FERROR, "%s list:%s\n", am_server ? "Server" : "Client", tmpbuf);
+	}
+
+	exit_cleanup(RERR_UNSUPPORTED);
+}
+
+static const char *getenv_nstr(int ntype)
+{
+	const char *env_str = getenv(ntype == NSTR_COMPRESS ? "RSYNC_COMPRESS_LIST" : "RSYNC_CHECKSUM_LIST");
+
+	/* When writing a batch file, we always negotiate an old-style choice. */
+	if (write_batch)
+		env_str = ntype == NSTR_COMPRESS ? "zlib" : protocol_version >= 30 ? "md5" : "md4";
+
+	if (am_server && env_str) {
+		char *cp = strchr(env_str, '&');
+		if (cp)
+			env_str = cp + 1;
+	}
+
+	return env_str;
+}
+
+void validate_choice_vs_env(int ntype, int num1, int num2)
+{
+	struct name_num_obj *nno = ntype == NSTR_COMPRESS ? &valid_compressions : &valid_checksums;
+	const char *list_str = getenv_nstr(ntype);
+	char tmpbuf[MAX_NSTR_STRLEN];
+
+	if (!list_str)
+		return;
+
+	while (isSpace(list_str)) list_str++;
+
+	if (!*list_str)
+		return;
+
+	init_nno_saw(nno, 0);
+	parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
+
+	if (ntype == NSTR_CHECKSUM) /* If "md4" is in the env list, all the old MD4 choices are OK too. */
+		nno->saw[CSUM_MD4_ARCHAIC] = nno->saw[CSUM_MD4_BUSTED] = nno->saw[CSUM_MD4_OLD] = nno->saw[CSUM_MD4];
+
+	if (!nno->saw[num1] || (num2 >= 0 && !nno->saw[num2])) {
+		rprintf(FERROR, "Your --%s-choice value (%s) was refused by the server.\n",
+			ntype == NSTR_COMPRESS ? "compress" : "checksum",
+			ntype == NSTR_COMPRESS ? compress_choice : checksum_choice);
+		exit_cleanup(RERR_UNSUPPORTED);
+	}
+
+	free(nno->saw);
+	nno->saw = NULL;
+}
+
+/* The saw buffer is initialized and used to store ordinal values from 1 to N
+ * for the order of the args in the array.  If dup_markup == '\0', duplicates
+ * are removed otherwise the char is prefixed to the duplicate term and, if it
+ * is an opening paren/bracket/brace, the matching closing char is suffixed.
+ * "none" is removed on the client side unless dup_markup != '\0'. */
+int get_default_nno_list(struct name_num_obj *nno, char *to_buf, int to_buf_len, char dup_markup)
+{
+	struct name_num_item *nni;
+	int len = 0, cnt = 0;
+	char delim = '\0', post_delim;
+
+	switch (dup_markup) {
+	case '(': post_delim = ')'; break;
+	case '[': post_delim = ']'; break;
+	case '{': post_delim = '}'; break;
+	default: post_delim = '\0'; break;
+	}
+
+	init_nno_saw(nno, 0);
+
+	for (nni = nno->list, len = 0; nni->name; nni++) {
+		if (nni->num == CSUM_gone)
+			continue;
+		if (nni->main_nni) {
+			if (!dup_markup || nni->main_nni->num == CSUM_gone)
+				continue;
+			delim = dup_markup;
+		}
+		if (nni->num == 0 && !am_server && !dup_markup)
+			continue;
+		if (len)
+			to_buf[len++]= ' ';
+		if (delim) {
+			to_buf[len++]= delim;
+			delim = post_delim;
+		}
+		len += strlcpy(to_buf+len, nni->name, to_buf_len - len);
+		if (len >= to_buf_len - 3)
+			exit_cleanup(RERR_UNSUPPORTED); /* IMPOSSIBLE... */
+		if (delim) {
+			to_buf[len++]= delim;
+			delim = '\0';
+		}
+		nno->saw[nni->num] = ++cnt;
+	}
+
+	return len;
+}
+
+static void send_negotiate_str(int f_out, struct name_num_obj *nno, int ntype)
+{
+	char tmpbuf[MAX_NSTR_STRLEN];
+	const char *list_str = getenv_nstr(ntype);
+	int len;
+
+	if (list_str && *list_str) {
+		init_nno_saw(nno, 0);
+		len = parse_nni_str(nno, list_str, tmpbuf, MAX_NSTR_STRLEN);
+		list_str = tmpbuf;
+	} else
+		list_str = NULL;
+
+	if (!list_str || !*list_str)
+		len = get_default_nno_list(nno, tmpbuf, MAX_NSTR_STRLEN, '\0');
+
+	if (DEBUG_GTE(NSTR, am_server ? 3 : 2)) {
+		if (am_server)
+			rprintf(FINFO, "Server %s list (on server): %s\n", nno->type, tmpbuf);
+		else
+			rprintf(FINFO, "Client %s list (on client): %s\n", nno->type, tmpbuf);
+	}
+
+	/* Each side sends their list of valid names to the other side and then both sides
+	 * pick the first name in the client's list that is also in the server's list. */
+	if (do_negotiated_strings)
+		write_vstring(f_out, tmpbuf, len);
+}
+
+static void negotiate_the_strings(int f_in, int f_out)
+{
+	/* We send all the negotiation strings before we start to read them to help avoid a slow startup. */
+
+	init_checksum_choices();
+
+	if (!checksum_choice)
+		send_negotiate_str(f_out, &valid_checksums, NSTR_CHECKSUM);
+
+	if (do_compression && !compress_choice)
+		send_negotiate_str(f_out, &valid_compressions, NSTR_COMPRESS);
+
+	if (valid_checksums.saw) {
+		char tmpbuf[MAX_NSTR_STRLEN];
+		int len;
+		if (do_negotiated_strings)
+			len = -1;
+		else
+			len = strlcpy(tmpbuf, protocol_version >= 30 ? "md5" : "md4", MAX_NSTR_STRLEN);
+		recv_negotiate_str(f_in, &valid_checksums, tmpbuf, len);
+	}
+
+	if (valid_compressions.saw) {
+		char tmpbuf[MAX_NSTR_STRLEN];
+		int len;
+		if (do_negotiated_strings)
+			len = -1;
+		else
+			len = strlcpy(tmpbuf, "zlib", MAX_NSTR_STRLEN);
+		recv_negotiate_str(f_in, &valid_compressions, tmpbuf, len);
+	}
+
+	/* If the other side is too old to negotiate, the above steps just made sure that
+	 * the env didn't disallow the old algorithm. Mark things as non-negotiated. */
+	if (!do_negotiated_strings)
+		valid_checksums.negotiated_nni = valid_compressions.negotiated_nni = NULL;
+}
+
+void setup_protocol(int f_out,int f_in)
+{
+	assert(file_extra_cnt == 0);
+	assert(EXTRA64_CNT == 2 || EXTRA64_CNT == 1);
+
+	/* All int64 values must be set first so that they are guaranteed to be
+	 * aligned for direct int64-pointer memory access. */
+	if (preserve_atimes)
+		atimes_ndx = (file_extra_cnt += EXTRA64_CNT);
+	if (preserve_crtimes)
+		crtimes_ndx = (file_extra_cnt += EXTRA64_CNT);
+	if (am_sender) /* This is most likely in the file_extras64 union as well. */
+		pathname_ndx = (file_extra_cnt += PTR_EXTRA_CNT);
+	else
+		depth_ndx = ++file_extra_cnt;
+	if (preserve_uid)
+		uid_ndx = ++file_extra_cnt;
+	if (preserve_gid)
+		gid_ndx = ++file_extra_cnt;
+	if (preserve_acls && !am_sender)
+		acls_ndx = ++file_extra_cnt;
+	if (preserve_xattrs)
+		xattrs_ndx = ++file_extra_cnt;
+
+	if (am_server)
+		set_allow_inc_recurse();
+
+	if (remote_protocol == 0) {
+		if (am_server && !local_server)
+			check_sub_protocol();
+		if (!read_batch)
+			write_int(f_out, protocol_version);
+		remote_protocol = read_int(f_in);
+		if (protocol_version > remote_protocol)
+			protocol_version = remote_protocol;
+	}
+	if (read_batch && remote_protocol > protocol_version) {
+		rprintf(FERROR, "The protocol version in the batch file is too new (%d > %d).\n",
+			remote_protocol, protocol_version);
+		exit_cleanup(RERR_PROTOCOL);
+	}
+
+	if (DEBUG_GTE(PROTO, 1)) {
+		rprintf(FINFO, "(%s) Protocol versions: remote=%d, negotiated=%d\n",
+			am_server? "Server" : "Client", remote_protocol, protocol_version);
+	}
+	if (remote_protocol < MIN_PROTOCOL_VERSION
+	 || remote_protocol > MAX_PROTOCOL_VERSION) {
+		rprintf(FERROR,"protocol version mismatch -- is your shell clean?\n");
+		rprintf(FERROR,"(see the rsync manpage for an explanation)\n");
+		exit_cleanup(RERR_PROTOCOL);
+	}
+	if (remote_protocol < OLD_PROTOCOL_VERSION) {
+		rprintf(FINFO,"%s is very old version of rsync, upgrade recommended.\n",
+			am_server? "Client" : "Server");
+	}
+	if (protocol_version < MIN_PROTOCOL_VERSION) {
+		rprintf(FERROR, "--protocol must be at least %d on the %s.\n",
+			MIN_PROTOCOL_VERSION, am_server? "Server" : "Client");
+		exit_cleanup(RERR_PROTOCOL);
+	}
+	if (protocol_version > PROTOCOL_VERSION) {
+		rprintf(FERROR, "--protocol must be no more than %d on the %s.\n",
+			PROTOCOL_VERSION, am_server? "Server" : "Client");
+		exit_cleanup(RERR_PROTOCOL);
+	}
+	if (read_batch)
+		check_batch_flags();
+
+	if (!saw_stderr_opt && protocol_version <= 28 && am_server)
+		msgs2stderr = 0; /* The client side may not have stderr setup for us. */
+
+#ifndef SUPPORT_PREALLOCATION
+	if (preallocate_files && !am_sender) {
+		rprintf(FERROR, "preallocation is not supported on this %s\n",
+			am_server ? "Server" : "Client");
+		exit_cleanup(RERR_SYNTAX);
+	}
+#endif
+
+	if (protocol_version < 30) {
+		if (append_mode == 1)
+			append_mode = 2;
+		if (preserve_acls && !local_server) {
+			rprintf(FERROR,
+				"--acls requires protocol 30 or higher"
+				" (negotiated %d).\n",
+				protocol_version);
+			exit_cleanup(RERR_PROTOCOL);
+		}
+		if (preserve_xattrs && !local_server) {
+			rprintf(FERROR,
+				"--xattrs requires protocol 30 or higher"
+				" (negotiated %d).\n",
+				protocol_version);
+			exit_cleanup(RERR_PROTOCOL);
+		}
+	}
+
+	if (delete_mode && !(delete_before+delete_during+delete_after)) {
+		if (protocol_version < 30)
+			delete_before = 1;
+		else
+			delete_during = 1;
+	}
+
+	if (protocol_version < 29) {
+		if (fuzzy_basis) {
+			rprintf(FERROR,
+				"--fuzzy requires protocol 29 or higher"
+				" (negotiated %d).\n",
+				protocol_version);
+			exit_cleanup(RERR_PROTOCOL);
+		}
+
+		if (basis_dir_cnt && inplace) {
+			rprintf(FERROR,
+				"%s with --inplace requires protocol 29 or higher"
+				" (negotiated %d).\n",
+				alt_dest_opt(0), protocol_version);
+			exit_cleanup(RERR_PROTOCOL);
+		}
+
+		if (basis_dir_cnt > 1) {
+			rprintf(FERROR,
+				"Using more than one %s option requires protocol"
+				" 29 or higher (negotiated %d).\n",
+				alt_dest_opt(0), protocol_version);
+			exit_cleanup(RERR_PROTOCOL);
+		}
+
+		if (prune_empty_dirs) {
+			rprintf(FERROR,
+				"--prune-empty-dirs requires protocol 29 or higher"
+				" (negotiated %d).\n",
+				protocol_version);
+			exit_cleanup(RERR_PROTOCOL);
+		}
+	} else if (protocol_version >= 30) {
+		if (am_server) {
+			compat_flags = allow_inc_recurse ? CF_INC_RECURSE : 0;
+#ifdef CAN_SET_SYMLINK_TIMES
+			compat_flags |= CF_SYMLINK_TIMES;
+#endif
+#ifdef ICONV_OPTION
+			compat_flags |= CF_SYMLINK_ICONV;
+#endif
+			if (strchr(client_info, 'f') != NULL)
+				compat_flags |= CF_SAFE_FLIST;
+			if (strchr(client_info, 'x') != NULL)
+				compat_flags |= CF_AVOID_XATTR_OPTIM;
+			if (strchr(client_info, 'C') != NULL)
+				compat_flags |= CF_CHKSUM_SEED_FIX;
+			if (strchr(client_info, 'I') != NULL)
+				compat_flags |= CF_INPLACE_PARTIAL_DIR;
+			if (strchr(client_info, 'u') != NULL)
+				compat_flags |= CF_ID0_NAMES;
+			if (strchr(client_info, 'v') != NULL) {
+				do_negotiated_strings = 1;
+				compat_flags |= CF_VARINT_FLIST_FLAGS;
+			}
+			if (strchr(client_info, 'V') != NULL) { /* Support a pre-release 'V' that got superseded */
+				if (!write_batch)
+					compat_flags |= CF_VARINT_FLIST_FLAGS;
+				write_byte(f_out, compat_flags);
+			} else
+				write_varint(f_out, compat_flags);
+		} else { /* read_varint() is compatible with the older write_byte() when the 0x80 bit isn't on. */
+			compat_flags = read_varint(f_in);
+			if  (compat_flags & CF_VARINT_FLIST_FLAGS)
+				do_negotiated_strings = 1;
+		}
+		/* The inc_recurse var MUST be set to 0 or 1. */
+		inc_recurse = compat_flags & CF_INC_RECURSE ? 1 : 0;
+		want_xattr_optim = protocol_version >= 31 && !(compat_flags & CF_AVOID_XATTR_OPTIM);
+		proper_seed_order = compat_flags & CF_CHKSUM_SEED_FIX ? 1 : 0;
+		xfer_flags_as_varint = compat_flags & CF_VARINT_FLIST_FLAGS ? 1 : 0;
+		xmit_id0_names = compat_flags & CF_ID0_NAMES ? 1 : 0;
+		if (!xfer_flags_as_varint && preserve_crtimes) {
+			fprintf(stderr, "Both rsync versions must be at least 3.2.0 for --crtimes.\n");
+			exit_cleanup(RERR_PROTOCOL);
+		}
+		if (am_sender) {
+			receiver_symlink_times = am_server
+			    ? strchr(client_info, 'L') != NULL
+			    : !!(compat_flags & CF_SYMLINK_TIMES);
+		}
+#ifdef CAN_SET_SYMLINK_TIMES
+		else
+			receiver_symlink_times = 1;
+#endif
+#ifdef ICONV_OPTION
+		sender_symlink_iconv = iconv_opt && (am_server
+		    ? strchr(client_info, 's') != NULL
+		    : !!(compat_flags & CF_SYMLINK_ICONV));
+#endif
+		if (inc_recurse && !allow_inc_recurse) {
+			/* This should only be able to happen in a batch. */
+			fprintf(stderr,
+				"Incompatible options specified for inc-recursive %s.\n",
+				read_batch ? "batch file" : "connection");
+			exit_cleanup(RERR_SYNTAX);
+		}
+		use_safe_inc_flist = (compat_flags & CF_SAFE_FLIST) || protocol_version >= 31;
+		need_messages_from_generator = 1;
+		if (compat_flags & CF_INPLACE_PARTIAL_DIR)
+			inplace_partial = 1;
+#ifdef CAN_SET_SYMLINK_TIMES
+	} else if (!am_sender) {
+		receiver_symlink_times = 1;
+#endif
+	}
+
+	if (read_batch)
+		do_negotiated_strings = 0;
+
+	if (need_unsorted_flist && (!am_sender || inc_recurse))
+		unsort_ndx = ++file_extra_cnt;
+
+	if (partial_dir && *partial_dir != '/' && (!am_server || local_server)) {
+		int rflags = FILTRULE_NO_PREFIXES | FILTRULE_DIRECTORY;
+		if (!am_sender || protocol_version >= 30)
+			rflags |= FILTRULE_PERISHABLE;
+		parse_filter_str(&filter_list, partial_dir, rule_template(rflags), 0);
+	}
+
+
+#ifdef ICONV_OPTION
+	if (protect_args && files_from) {
+		if (am_sender)
+			filesfrom_convert = filesfrom_host && ic_send != (iconv_t)-1;
+		else
+			filesfrom_convert = !filesfrom_host && ic_recv != (iconv_t)-1;
+	}
+#endif
+
+	negotiate_the_strings(f_in, f_out);
+
+	if (am_server) {
+		if (!checksum_seed)
+			checksum_seed = time(NULL) ^ (getpid() << 6);
+		write_int(f_out, checksum_seed);
+	} else {
+		checksum_seed = read_int(f_in);
+	}
+
+	parse_checksum_choice(1); /* Sets file_sum_nni & xfer_sum_nni */
+	parse_compress_choice(1); /* Sets do_compression */
+
+	/* TODO in the future allow this algorithm to be chosen somehow, but it can't get too
+	 * long or the size starts to cause a problem in the xattr abbrev/non-abbrev code. */
+	xattr_sum_nni = parse_csum_name(NULL, 0);
+	xattr_sum_len = csum_len_for_type(xattr_sum_nni->num, 0);
+
+	if (write_batch && !am_server)
+		write_batch_shell_file();
+
+	init_flist();
+}
+
+void output_daemon_greeting(int f_out, int am_client)
+{
+	char tmpbuf[MAX_NSTR_STRLEN];
+	int our_sub = get_subprotocol_version();
+
+	get_default_nno_list(&valid_auth_checksums, tmpbuf, MAX_NSTR_STRLEN, '\0');
+
+	io_printf(f_out, "@RSYNCD: %d.%d %s\n", protocol_version, our_sub, tmpbuf);
+
+	if (am_client && DEBUG_GTE(NSTR, 2))
+		rprintf(FINFO, "Client %s list (on client): %s\n", valid_auth_checksums.type, tmpbuf);
+}
+
+void negotiate_daemon_auth(int f_out, int am_client)
+{
+	char tmpbuf[MAX_NSTR_STRLEN];
+	int save_am_server = am_server;
+	int md4_is_old = 0;
+
+	if (!am_client)
+		am_server = 1;
+
+	if (daemon_auth_choices)
+		strlcpy(tmpbuf, daemon_auth_choices, MAX_NSTR_STRLEN);
+	else {
+		strlcpy(tmpbuf, protocol_version >= 30 ? "md5" : "md4", MAX_NSTR_STRLEN);
+		md4_is_old = 1;
+	}
+
+	if (am_client) {
+		recv_negotiate_str(-1, &valid_auth_checksums, tmpbuf, strlen(tmpbuf));
+		if (DEBUG_GTE(NSTR, 1)) {
+			rprintf(FINFO, "Client negotiated %s: %s\n", valid_auth_checksums.type,
+				valid_auth_checksums.negotiated_nni->name);
+		}
+	} else {
+		if (!parse_negotiate_str(&valid_auth_checksums, tmpbuf)) {
+			get_default_nno_list(&valid_auth_checksums, tmpbuf, MAX_NSTR_STRLEN, '\0');
+			io_printf(f_out, "@ERROR: your client does not support one of our daemon-auth checksums: %s\n",
+				  tmpbuf);
+			exit_cleanup(RERR_UNSUPPORTED);
+		}
+	}
+	am_server = save_am_server;
+	if (md4_is_old && valid_auth_checksums.negotiated_nni->num == CSUM_MD4)
+		valid_auth_checksums.negotiated_nni->num = CSUM_MD4_OLD;
+}
+
+int get_subprotocol_version()
+{
+#if SUBPROTOCOL_VERSION != 0
+	return protocol_version < PROTOCOL_VERSION ? 0 : SUBPROTOCOL_VERSION;
+#else
+	return 0;
+#endif
+}