RsyncProject · cicku · Jun 9, 2026
diff --git a/.github/workflows/almalinux-8-build.yml b/.github/workflows/almalinux-8-build.yml
@@ -48,7 +48,8 @@ jobs:
             attr libattr-devel acl libacl-devel \
             zstd libzstd-devel \
             lz4 lz4-devel \
-            xxhash xxhash-devel
+            xxhash xxhash-devel \
+            libidn2 libidn2-devel
         alternatives --set python3 /usr/bin/python3.9
         pip3 install commonmark
     - name: configure

diff --git a/.github/workflows/android-static-build.yml b/.github/workflows/android-static-build.yml
@@ -76,7 +76,7 @@ jobs:
           # checksums and its bundled zlib.
           ./configure --host=${{ matrix.triple }} --build=x86_64-pc-linux-gnu \
             --enable-ipv6 \
-            --disable-zstd --disable-lz4 --disable-xxhash --disable-openssl \
+            --disable-zstd --disable-lz4 --disable-xxhash --disable-openssl --disable-idn \
             --disable-iconv --disable-iconv-open \
             --disable-acl-support --disable-xattr-support \
             --disable-md2man --disable-roll-simd \

diff --git a/.github/workflows/asan-build.yml b/.github/workflows/asan-build.yml
@@ -41,7 +41,7 @@ jobs:
     - name: prep
       run: |
         sudo apt-get update
-        sudo apt-get install -y clang acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev openssl
+        sudo apt-get install -y clang acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev libidn2-dev openssl
         echo "/usr/local/bin" >>"$GITHUB_PATH"
     - name: configure
       # -DNDEBUG builds as a shipped release does (assert() compiled out), so

diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
@@ -26,7 +26,7 @@ jobs:
     - name: prep
       run: |
         sudo apt-get update
-        sudo apt-get install -y acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev python3-cmarkgfm openssl gcovr
+        sudo apt-get install -y acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev libidn2-dev python3-cmarkgfm openssl gcovr
         echo "/usr/local/bin" >>"$GITHUB_PATH"
     - name: configure
       run: ./configure --enable-coverage --with-rrsync

diff --git a/.github/workflows/cygwin-build.yml b/.github/workflows/cygwin-build.yml
@@ -26,7 +26,7 @@ jobs:
       run: choco install -y --no-progress cygwin cyg-get
     - name: prep
       run: |
-        cyg-get make autoconf automake gcc-core attr libattr-devel python39 python39-pip libzstd-devel liblz4-devel libssl-devel libxxhash0 libxxhash-devel
+        cyg-get make autoconf automake gcc-core attr libattr-devel python39 python39-pip libzstd-devel liblz4-devel libssl-devel libxxhash0 libxxhash-devel libidn2-devel
         echo "C:/tools/cygwin/bin" >>$Env:GITHUB_PATH
     - name: commonmark
       run: bash -c 'python3 -mpip install --user commonmark'

diff --git a/.github/workflows/fleettest.yml b/.github/workflows/fleettest.yml
@@ -33,7 +33,7 @@ jobs:
       run: |
         sudo apt-get update
         sudo apt-get install -y gcc g++ gawk autoconf automake \
-          acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev \
+          acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev libidn2-dev \
           python3-cmarkgfm openssl rsync openssh-server
     - name: set up ssh to localhost
       run: |

diff --git a/.github/workflows/freebsd-build.yml b/.github/workflows/freebsd-build.yml
@@ -31,7 +31,7 @@ jobs:
           pkg install -y bash autotools m4 devel/xxhash zstd liblz4 python3 archivers/liblz4 git
         run: |
           freebsd-version
-          ./configure --with-rrsync -disable-zstd --disable-md2man --disable-xxhash --disable-lz4
+          ./configure --with-rrsync -disable-zstd --disable-md2man --disable-xxhash --disable-lz4 --disable-idn
           make
           ./rsync --version
           make check

diff --git a/.github/workflows/macos-build.yml b/.github/workflows/macos-build.yml
@@ -24,7 +24,7 @@ jobs:
         fetch-depth: 0
     - name: prep
       run: |
-        brew install automake openssl xxhash zstd lz4
+        brew install automake openssl xxhash zstd lz4 libidn2
         pip3 install --user --break-system-packages commonmark
         echo "$(brew --prefix)/bin" >>"$GITHUB_PATH"
     - name: configure

diff --git a/.github/workflows/netbsd-build.yml b/.github/workflows/netbsd-build.yml
@@ -32,7 +32,7 @@ jobs:
           ln -sf /usr/pkg/bin/python3.12 /usr/pkg/bin/python3
         run: |
           uname -a
-          ./configure --with-rrsync --disable-zstd --disable-md2man --disable-xxhash --disable-lz4
+          ./configure --with-rrsync --disable-zstd --disable-md2man --disable-xxhash --disable-lz4 --disable-idn
           make
           ./rsync --version
           make check

diff --git a/.github/workflows/openbsd-build.yml b/.github/workflows/openbsd-build.yml
@@ -33,7 +33,7 @@ jobs:
           uname -a
           export AUTOCONF_VERSION=2.71
           export AUTOMAKE_VERSION=1.16
-          ./configure --with-rrsync --disable-zstd --disable-md2man --disable-xxhash --disable-lz4
+          ./configure --with-rrsync --disable-zstd --disable-md2man --disable-xxhash --disable-lz4 --disable-idn
           make
           ./rsync --version
           make check

diff --git a/.github/workflows/scan-build.yml b/.github/workflows/scan-build.yml
@@ -24,7 +24,7 @@ jobs:
     - name: prep
       run: |
         sudo apt-get update
-        sudo apt-get install -y clang clang-tools acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev openssl
+        sudo apt-get install -y clang clang-tools acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev libidn2-dev openssl
     - name: configure (under scan-build)
       # Run configure under scan-build so its analyzer compiler-wrapper is baked
       # into the Makefile's $(CC); --disable-md2man avoids the doc toolchain.

diff --git a/.github/workflows/solaris-build.yml b/.github/workflows/solaris-build.yml
@@ -31,7 +31,7 @@ jobs:
           pkg install bash automake gnu-m4 pkg://solaris/runtime/python-35 autoconf gcc git
         run: |
           uname -a
-          ./configure --with-rrsync -disable-zstd --disable-md2man --disable-xxhash --disable-lz4
+          ./configure --with-rrsync -disable-zstd --disable-md2man --disable-xxhash --disable-lz4 --disable-idn
           make
           ./rsync --version
           make check

diff --git a/.github/workflows/ubuntu-22.04-build.yml b/.github/workflows/ubuntu-22.04-build.yml
@@ -28,7 +28,7 @@ jobs:
         fetch-depth: 0
     - name: prep
       run: |
-        sudo apt-get install acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev python3-cmarkgfm openssl
+        sudo apt-get install acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev libidn2-dev python3-cmarkgfm openssl
         echo "/usr/local/bin" >>"$GITHUB_PATH"
     - name: configure
       run: ./configure --with-rrsync

diff --git a/.github/workflows/ubuntu-build.yml b/.github/workflows/ubuntu-build.yml
@@ -24,7 +24,7 @@ jobs:
         fetch-depth: 0
     - name: prep
       run: |
-        sudo apt-get install acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev python3-cmarkgfm openssl
+        sudo apt-get install acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev libidn2-dev python3-cmarkgfm openssl
         echo "/usr/local/bin" >>"$GITHUB_PATH"
     - name: configure
       run: ./configure --with-rrsync

diff --git a/.github/workflows/ubuntu-version-mix.yml b/.github/workflows/ubuntu-version-mix.yml
@@ -45,7 +45,7 @@ jobs:
         fetch-depth: 0
     - name: prep
       run: |
-        sudo apt-get install acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev python3-cmarkgfm openssl
+        sudo apt-get install acl libacl1-dev attr libattr1-dev liblz4-dev libzstd-dev libxxhash-dev libidn2-dev python3-cmarkgfm openssl
         echo "/usr/local/bin" >>"$GITHUB_PATH"
     - name: configure
       run: ./configure --with-rrsync

diff --git a/access.c b/access.c
@@ -23,6 +23,9 @@
 #ifdef HAVE_NETGROUP_H
 #include <netgroup.h>
 #endif
+#ifdef SUPPORT_IDN
+#include <idn2.h>
+#endif
 
 static int allow_forward_dns;
 
@@ -33,6 +36,9 @@ static int match_hostname(const char **host_ptr, const char *addr, const char *t
 	struct hostent *hp;
 	unsigned int i;
 	const char *host = *host_ptr;
+#ifdef SUPPORT_IDN
+	char idn_tok[1024], *idn;
+#endif
 
 	if (!host || !*host)
 		return 0;
@@ -42,6 +48,14 @@ static int match_hostname(const char **host_ptr, const char *addr, const char *t
 		return innetgr(tok + 1, host, NULL, NULL);
 #endif
 
+#ifdef SUPPORT_IDN
+	if (idn2_to_ascii_8z(tok, &idn, IDN2_NFC_INPUT | IDN2_NONTRANSITIONAL) == IDN2_OK) {
+		strlcpy(idn_tok, idn, sizeof idn_tok);
+		idn2_free(idn);
+		tok = idn_tok;
+	}
+#endif
+
 	/* First check if the reverse-DNS-determined hostname matches. */
 	if (iwildmatch(tok, host))
 		return 1;

diff --git a/configure.ac b/configure.ac
@@ -13,7 +13,7 @@ AC_CHECK_HEADERS(sys/fcntl.h sys/select.h fcntl.h sys/time.h sys/unistd.h \
     sys/acl.h acl/libacl.h attr/xattr.h sys/xattr.h sys/extattr.h dl.h \
     popt.h popt/popt.h linux/falloc.h netinet/in_systm.h netgroup.h \
     zlib.h xxhash.h openssl/md4.h openssl/md5.h zstd.h lz4.h sys/file.h \
-    bsd/string.h)
+    bsd/string.h idn2.h)
 AC_CHECK_HEADERS([netinet/ip.h], [], [], [[#include <netinet/in.h>]])
 AC_HEADER_MAJOR_FIXED
 
@@ -626,6 +626,27 @@ else
     AC_MSG_RESULT(no)
 fi
 
+AC_MSG_CHECKING([whether to enable IDN support])
+AC_ARG_ENABLE([idn],
+        AS_HELP_STRING([--disable-idn], [disable to omit IDN (Internationalized Domain Name) support]))
+AH_TEMPLATE([SUPPORT_IDN],
+[Undefine if you do not want IDN support.  By default this is defined.])
+if test x"$enable_idn" != x"no"; then
+    if test x"$ac_cv_header_idn2_h" = x"yes"; then
+	AC_MSG_RESULT(yes)
+	AC_SEARCH_LIBS(idn2_lookup_ul, idn2,
+	    [AC_DEFINE(SUPPORT_IDN)],
+	    [err_msg="$err_msg$nl- Failed to find idn2_lookup_ul function in idn2 lib.";
+	     no_lib="$no_lib idn"])
+    else
+	AC_MSG_RESULT(no)
+	err_msg="$err_msg$nl- Failed to find idn2.h for IDN support."
+	no_lib="$no_lib idn"
+    fi
+else
+    AC_MSG_RESULT(no)
+fi
+
 if test x"$no_lib" != x; then
     echo ""
     echo "Configure found the following issues:"

diff --git a/main.c b/main.c
@@ -31,6 +31,9 @@
 #ifdef __TANDEM
 #include <floss.h(floss_execlp)>
 #endif
+#ifdef SUPPORT_IDN
+#include <idn2.h>
+#endif
 
 extern int dry_run;
 extern int list_only;
@@ -517,6 +520,18 @@ static pid_t do_cmd(char *cmd, char *machine, char *user, char **remote_argv, in
 	char *args[MAX_ARGS], *need_to_free = NULL;
 	pid_t pid;
 	int dash_l_set = 0;
+#ifdef SUPPORT_IDN
+	char idn_machine[1024];
+
+	if (machine && daemon_connection > 0) {
+		char *idn;
+		if (idn2_lookup_ul(machine, &idn, IDN2_NONTRANSITIONAL) == IDN2_OK) {
+			strlcpy(idn_machine, idn, sizeof idn_machine);
+			idn2_free(idn);
+			machine = idn_machine;
+		}
+	}
+#endif
 
 	if (!read_batch && !local_server) {
 		char *t, *f, in_quote = '\0';

diff --git a/socket.c b/socket.c
@@ -34,6 +34,9 @@
 #include <netinet/ip.h>
 #endif
 #include <netinet/tcp.h>
+#ifdef SUPPORT_IDN
+#include <idn2.h>
+#endif
 
 extern char *bind_address;
 extern char *sockopts;
@@ -196,6 +199,15 @@ int open_socket_out(char *host, int port, const char *bind_addr, int af_hint)
 	int proxied = 0;
 	char buffer[1024];
 	char *proxy_user = NULL, *proxy_pass = NULL;
+#ifdef SUPPORT_IDN
+	char *idn, idn_host[1024];
+
+	if (idn2_lookup_ul(host, &idn, IDN2_NONTRANSITIONAL) == IDN2_OK) {
+		strlcpy(idn_host, idn, sizeof idn_host);
+		idn2_free(idn);
+		host = idn_host;
+	}
+#endif
 
 	/* if we have a RSYNC_PROXY env variable then redirect our
 	 * connection via a web proxy at the given address. */