From 6da213500acdf779fcae9749cec487bf4a79c75f Mon Sep 17 00:00:00 2001
From: =?utf8?q?Juho=20V=C3=A4h=C3=A4-Herttua?= <juhovh@iki.fi>
Date: Sat, 19 May 2012 14:17:18 +0300
Subject: [PATCH] Add libdl support to dnssd.c for lazy linking

---
 src/lib/dnssd.c | 49 ++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 42 insertions(+), 7 deletions(-)

diff --git a/src/lib/dnssd.c b/src/lib/dnssd.c
index dea8137..53f238c 100644
--- a/src/lib/dnssd.c
+++ b/src/lib/dnssd.c
@@ -26,14 +26,18 @@
 #define MAX_DEVICEID 18
 #define MAX_SERVNAME 256
 
-#ifndef WIN32
-# include <dns_sd.h>
-# define DNSSD_STDCALL
-#else
-# include <stdint.h>
-# if !defined(EFI32) && !defined(EFI64)
-#  define DNSSD_STDCALL __stdcall
+#define USE_LIBDL (defined(HAVE_LIBDL) && !defined(__APPLE__))
+
+#if defined(WIN32) || USE_LIBDL
+# ifdef WIN32
+#  include <stdint.h>
+#  if !defined(EFI32) && !defined(EFI64)
+#   define DNSSD_STDCALL __stdcall
+#  else
+#   define DNSSD_STDCALL
+#  endif
 # else
+#  include <dlfcn.h>
 #  define DNSSD_STDCALL
 # endif
 
@@ -53,6 +57,10 @@ typedef void (DNSSD_STDCALL *DNSServiceRegisterReply)
     const char                          *domain,
     void                                *context
     );
+
+#else
+# include <dns_sd.h>
+# define DNSSD_STDCALL
 #endif
 
 typedef DNSServiceErrorType (DNSSD_STDCALL *DNSServiceRegister_t)
@@ -92,6 +100,8 @@ typedef const void * (DNSSD_STDCALL *TXTRecordGetBytesPtr_t)(const TXTRecordRef
 struct dnssd_s {
 #ifdef WIN32
 	HMODULE module;
+#elif USE_LIBDL
+	void *module;
 #endif
 
 	DNSServiceRegister_t       DNSServiceRegister;
@@ -144,6 +154,29 @@ dnssd_init(int *error)
 		free(dnssd);
 		return NULL;
 	}
+#elif USE_LIBDL
+	dnssd->module = dlopen("libdns_sd.so", RTLD_LAZY);
+	if (!dnssd->module) {
+		if (error) *error = DNSSD_ERROR_LIBNOTFOUND;
+		free(dnssd);
+		return NULL;
+	}
+	dnssd->DNSServiceRegister = (DNSServiceRegister_t)dlsym(dnssd->module, "DNSServiceRegister");
+	dnssd->DNSServiceRefDeallocate = (DNSServiceRefDeallocate_t)dlsym(dnssd->module, "DNSServiceRefDeallocate");
+	dnssd->TXTRecordCreate = (TXTRecordCreate_t)dlsym(dnssd->module, "TXTRecordCreate");
+	dnssd->TXTRecordSetValue = (TXTRecordSetValue_t)dlsym(dnssd->module, "TXTRecordSetValue");
+	dnssd->TXTRecordGetLength = (TXTRecordGetLength_t)dlsym(dnssd->module, "TXTRecordGetLength");
+	dnssd->TXTRecordGetBytesPtr = (TXTRecordGetBytesPtr_t)dlsym(dnssd->module, "TXTRecordGetBytesPtr");
+	dnssd->TXTRecordDeallocate = (TXTRecordDeallocate_t)dlsym(dnssd->module, "TXTRecordDeallocate");
+
+	if (!dnssd->DNSServiceRegister || !dnssd->DNSServiceRefDeallocate || !dnssd->TXTRecordCreate ||
+	    !dnssd->TXTRecordSetValue || !dnssd->TXTRecordGetLength || !dnssd->TXTRecordGetBytesPtr ||
+	    !dnssd->TXTRecordDeallocate) {
+		if (error) *error = DNSSD_ERROR_PROCNOTFOUND;
+		dlclose(dnssd->module);
+		free(dnssd);
+		return NULL;
+	}
 #else
 	dnssd->DNSServiceRegister = &DNSServiceRegister;
 	dnssd->DNSServiceRefDeallocate = &DNSServiceRefDeallocate;
@@ -163,6 +196,8 @@ dnssd_destroy(dnssd_t *dnssd)
 	if (dnssd) {
 #ifdef WIN32
 		FreeLibrary(dnssd->module);
+#elif USE_LIBDL
+		dlclose(dnssd->module);
 #endif
 		free(dnssd);
 	}
-- 
2.34.1