1 files changed, 91 insertions, 0 deletions
diff --git a/src/shared/idn-util.c b/src/shared/idn-util.c
new file mode 100644
index 0000000..83c4b3c
--- /dev/null
+++ b/src/shared/idn-util.c
@@ -0,0 +1,91 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#if HAVE_LIBIDN2
+#  include <idn2.h>
+#elif HAVE_LIBIDN
+#  include <idna.h>
+#  include <stringprep.h>
+#endif
+
+#include "alloc-util.h"
+#include "dlfcn-util.h"
+#include "idn-util.h"
+
+#if HAVE_LIBIDN || HAVE_LIBIDN2
+static void* idn_dl = NULL;
+#endif
+
+#if HAVE_LIBIDN2
+int (*sym_idn2_lookup_u8)(const uint8_t* src, uint8_t** lookupname, int flags) = NULL;
+const char *(*sym_idn2_strerror)(int rc) = NULL;
+int (*sym_idn2_to_unicode_8z8z)(const char * input, char ** output, int flags) = NULL;
+
+int dlopen_idn(void) {
+        _cleanup_(dlclosep) void *dl = NULL;
+        int r;
+
+        if (idn_dl)
+                return 0; /* Already loaded */
+
+        dl = dlopen("libidn2.so.0", RTLD_LAZY);
+        if (!dl)
+                return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                       "libidn2 support is not installed: %s", dlerror());
+
+        r = dlsym_many_and_warn(
+                        dl,
+                        LOG_DEBUG,
+                        &sym_idn2_lookup_u8, "idn2_lookup_u8",
+                        &sym_idn2_strerror, "idn2_strerror",
+                        &sym_idn2_to_unicode_8z8z, "idn2_to_unicode_8z8z",
+                        NULL);
+        if (r < 0)
+                return r;
+
+        /* Note that we never release the reference here, because there's no real reason to, after all this
+         * was traditionally a regular shared library dependency which lives forever too. */
+        idn_dl = TAKE_PTR(dl);
+
+        return 1;
+}
+#endif
+
+#if HAVE_LIBIDN
+int (*sym_idna_to_ascii_4i)(const uint32_t * in, size_t inlen, char *out, int flags);
+int (*sym_idna_to_unicode_44i)(const uint32_t * in, size_t inlen,uint32_t * out, size_t * outlen, int flags);
+char* (*sym_stringprep_ucs4_to_utf8)(const uint32_t * str, ssize_t len, size_t * items_read, size_t * items_written);
+uint32_t* (*sym_stringprep_utf8_to_ucs4)(const char *str, ssize_t len, size_t *items_written);
+
+int dlopen_idn(void) {
+        _cleanup_(dlclosep) void *dl = NULL;
+        int r;
+
+        if (idn_dl)
+                return 0; /* Already loaded */
+
+        dl = dlopen("libidn.so.12", RTLD_LAZY);
+        if (!dl) {
+                /* libidn broke ABI in 1.34, but not in a way we care about (a new field got added to an
+                 * open-coded struct we do not use), hence support both versions. */
+                dl = dlopen("libidn.so.11", RTLD_LAZY);
+                if (!dl)
+                        return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                               "libidn support is not installed: %s", dlerror());
+        }
+
+        r = dlsym_many_and_warn(
+                        dl,
+                        LOG_DEBUG,
+                        &sym_idna_to_ascii_4i, "idna_to_ascii_4i",
+                        &sym_idna_to_unicode_44i, "idna_to_unicode_44i",
+                        &sym_stringprep_ucs4_to_utf8, "stringprep_ucs4_to_utf8",
+                        &sym_stringprep_utf8_to_ucs4, "stringprep_utf8_to_ucs4",
+                        NULL);
+        if (r < 0)
+                return r;
+
+        idn_dl = TAKE_PTR(dl);
+
+        return 1;
+}
+#endif