Add openconnect_utf8_to_legacy() helper function for charset conversion

In some cases, the library itself really is going to have to know about
legacy non-UTF8 locales — when opening files or setting environment
variables, for example.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

Makefile.am

@@ -25,6 +25,7 @@ lib_srcs_openssl = openssl.c
 lib_srcs_win32 = tun-win32.c sspi.c
 lib_srcs_posix = tun.c
 lib_srcs_gssapi = gssapi.c
+lib_srcs_iconv = iconv.c
 
 POTFILES = $(openconnect_SOURCES) $(lib_srcs_openssl) $(lib_srcs_gnutls) \
 	   $(library_srcs) $(lib_srcs_win32) $(lib_srcs_posix) $(lib_srcs_gssapi)
@@ -38,6 +39,9 @@ endif
 if OPENCONNECT_OPENSSL
 library_srcs += $(lib_srcs_openssl)
 endif
+if OPENCONNECT_ICONV
+library_srcs += $(lib_srcs_iconv)
+endif
 if OPENCONNECT_WIN32
 library_srcs += $(lib_srcs_win32)
 else
@@ -46,7 +50,7 @@ endif
 
 libopenconnect_la_SOURCES = version.c $(library_srcs)
 libopenconnect_la_CFLAGS = $(AM_CFLAGS) $(SSL_CFLAGS) $(DTLS_SSL_CFLAGS) $(LIBXML2_CFLAGS) $(LIBPROXY_CFLAGS) $(ZLIB_CFLAGS) $(P11KIT_CFLAGS) $(TSS_CFLAGS) $(LIBSTOKEN_CFLAGS) $(LIBOATH_CFLAGS) $(GSSAPI_CFLAGS)
-libopenconnect_la_LIBADD = $(SSL_LIBS) $(DTLS_SSL_LIBS) $(LIBXML2_LIBS) $(LIBPROXY_LIBS) $(ZLIB_LIBS) $(LIBINTL) $(P11KIT_LIBS) $(TSS_LIBS) $(LIBSTOKEN_LIBS) $(LIBOATH_LIBS) $(GSSAPI_LIBS)
+libopenconnect_la_LIBADD = $(SSL_LIBS) $(DTLS_SSL_LIBS) $(LIBXML2_LIBS) $(LIBPROXY_LIBS) $(ZLIB_LIBS) $(LIBINTL) $(P11KIT_LIBS) $(TSS_LIBS) $(LIBSTOKEN_LIBS) $(LIBOATH_LIBS) $(GSSAPI_LIBS) $(LIBICONV)
 if OPENBSD_LIBTOOL
 # OpenBSD's libtool doesn't have -version-number, but its -version-info arg
 # does what GNU libtool's -version-number does. Which arguably is what the

configure.ac

@@ -181,8 +181,8 @@ AC_DISABLE_STATIC
 
 AC_CHECK_FUNC(nl_langinfo, [AC_DEFINE(HAVE_NL_LANGINFO, 1, [Have nl_langinfo() function])], [])
 
+have_iconv=no
 if test "$ac_cv_func_nl_langinfo" = "yes"; then
-    have_iconv=no
     LIBICONV=
     AC_MSG_CHECKING([for iconv support])
     AC_LINK_IFELSE([AC_LANG_PROGRAM([
@@ -205,6 +205,7 @@ if test "$ac_cv_func_nl_langinfo" = "yes"; then
         AC_DEFINE(HAVE_ICONV, 1, [Have iconv() function])
     fi
 fi
+AM_CONDITIONAL(OPENCONNECT_ICONV, [test "$have_iconv" = "yes"])
 
 AC_ARG_ENABLE([nls],
 	[  --disable-nls           do not use Native Language Support],

iconv.c

@@ -0,0 +1,91 @@
+/*
+ * OpenConnect (SSL + DTLS) VPN client
+ *
+ * Copyright © 2008-2014 Intel Corporation.
+ *
+ * Author: David Woodhouse <dwmw2@infradead.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1, as published by the Free Software Foundation.
+ *
+ * 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
+ * Lesser General Public License for more details.
+ */
+
+#include <config.h>
+
+#include <iconv.h>
+#include <errno.h>
+#include <string.h>
+
+#include "openconnect-internal.h"
+
+static char *convert_str(struct openconnect_info *vpninfo, iconv_t ic,
+			 char *instr)
+
+{
+	char *ic_in, *ic_out, *outstr;
+	size_t insize, outsize;
+	int addq = 0;
+
+	if (ic == (iconv_t)-1)
+		return instr;
+
+	iconv(ic, NULL, NULL, NULL, NULL);
+
+	insize = strlen(instr) + 1;
+	ic_in = instr;
+
+	outsize = insize;
+	ic_out = outstr = malloc(outsize);
+	if (!outstr)
+		return instr;
+
+	while (insize) {
+		if (iconv(ic, &ic_in, &insize, &ic_out, &outsize) == (size_t)-1) {
+			perror("iconv");
+			if (errno == EILSEQ) {
+				do {
+					ic_in++;
+					insize--;
+				} while (insize && (ic_in[0] & 0xc0) == 0x80);
+				addq = 1;
+			}
+
+			if (!outsize || errno == E2BIG) {
+				int outlen = ic_out - outstr;
+				realloc_inplace(outstr, outlen + 10);
+				if (!outstr)
+					return instr;
+				ic_out = outstr + outlen;
+				outsize = 10;
+			} else if (errno != EILSEQ) {
+				/* Should never happen */
+				free(outstr);
+				return instr;
+			}
+			if (addq) {
+				addq = 0;
+				*(ic_out++) = '?';
+				outsize--;
+			}
+		}
+	}
+
+	return outstr;
+}
+
+char *openconnect_legacy_to_utf8(struct openconnect_info *vpninfo,
+				 const char *legacy)
+{
+	return convert_str(vpninfo, vpninfo->ic_legacy_to_utf8, (char *)legacy);
+}
+
+char *openconnect_utf8_to_legacy(struct openconnect_info *vpninfo,
+				 const char *utf8)
+{
+	return convert_str(vpninfo, vpninfo->ic_utf8_to_legacy, (char *)utf8);
+}

library.c

@@ -45,10 +45,22 @@ struct openconnect_info *openconnect_vpninfo_new(char *useragent,
 						 void *privdata)
 {
 	struct openconnect_info *vpninfo = calloc(sizeof(*vpninfo), 1);
+#ifdef HAVE_ICONV
+	char *charset = nl_langinfo(CODESET);
+#endif
 
 	if (!vpninfo)
 		return NULL;
 
+#ifdef HAVE_ICONV
+	if (charset && strcmp(charset, "UTF-8")) {
+		vpninfo->ic_utf8_to_legacy = iconv_open(charset, "UTF-8");
+		vpninfo->ic_legacy_to_utf8 = iconv_open("UTF-8", charset);
+	} else {
+		vpninfo->ic_utf8_to_legacy = (iconv_t)-1;
+		vpninfo->ic_legacy_to_utf8 = (iconv_t)-1;
+	}
+#endif
 #ifndef _WIN32
 	vpninfo->tun_fd = -1;
 #endif
@@ -141,6 +153,11 @@ void openconnect_vpninfo_free(struct openconnect_info *vpninfo)
 		close(vpninfo->cmd_fd);
 		close(vpninfo->cmd_fd_write);
 	}
+
+#ifdef HAVE_ICONV
+	iconv_close(vpninfo->ic_utf8_to_legacy);
+	iconv_close(vpninfo->ic_legacy_to_utf8);
+#endif
 #ifdef _WIN32
 	if (vpninfo->cmd_event)
 		CloseHandle(vpninfo->cmd_event);

openconnect-internal.h

@@ -62,6 +62,11 @@
 #endif
 #endif
 
+#ifdef HAVE_ICONV
+#include <langinfo.h>
+#include <iconv.h>
+#endif
+
 #include <zlib.h>
 #include <stdint.h>
 #include <sys/time.h>
@@ -174,6 +179,10 @@ struct proxy_auth_state {
 };
 
 struct openconnect_info {
+#ifdef HAVE_ICONV
+	iconv_t ic_legacy_to_utf8;
+	iconv_t ic_utf8_to_legacy;
+#endif
 	char *redirect_url;
 	int redirect_type;
 
@@ -521,6 +530,15 @@ int dumb_socketpair(int socks[2], int make_overlapped);
 
 /****************************************************************************/
 
+/* iconv.c */
+#ifdef HAVE_ICONV
+char *openconnect_utf8_to_legacy(struct openconnect_info *vpninfo, const char *utf8);
+char *openconnect_legacy_to_utf8(struct openconnect_info *vpninfo, const char *legacy);
+#else
+#define openconnect_utf8_to_legacy(v, str) ((char *)str)
+#define openconnect_legacy_to_utf8(v, str) ((char *)str)
+#endif
+
 /* script.c */
 int setenv_int(const char *opt, int value);
 void set_script_env(struct openconnect_info *vpninfo);