From f518f75149198ed45c1124f646e1351910279d21 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <icculus@icculus.org>
Date: Tue, 30 May 2017 20:15:59 -0400
Subject: [PATCH] Don't link directly to libcurl.

Lots of Linux distros have different names (libcurl-gnutls.so vs etc), and
version the symbols (curl_global_init@@CURL_LIBSSL_3), so it's more compatible
to just dlsym the basic entry points we need and just demand that libcurl is
installed at all.

Alternately: we'll use our own libcurl build, but we'll probably have to dump
SSL support to make this sane to do.
---
 Makefile                       |  2 +-
 code/autoupdater/autoupdater.c | 59 +++++++++++++++++++++++++++++++++-
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 99f2ffe4..73db3f73 100644
--- a/Makefile
+++ b/Makefile
@@ -1588,7 +1588,7 @@ $(B)/autoupdater/%.o: $(AUTOUPDATERSRCDIR)/%.c
 
 $(B)/$(AUTOUPDATER_BIN): $(Q3AUTOUPDATEROBJ)
 	$(echo_cmd) "AUTOUPDATER_LD $@"
-	$(Q)$(CC) $(LDFLAGS) -o $@ $(Q3AUTOUPDATEROBJ) $(CURL_LIBS)
+	$(Q)$(CC) $(LDFLAGS) -o $@ $(Q3AUTOUPDATEROBJ) $(LIBS)
 
 
 #############################################################################
diff --git a/code/autoupdater/autoupdater.c b/code/autoupdater/autoupdater.c
index f2e05357..cffbfb52 100644
--- a/code/autoupdater/autoupdater.c
+++ b/code/autoupdater/autoupdater.c
@@ -151,8 +151,61 @@ static void restoreRollbacks(void)
     }
 }
 
-
 static void die(const char *why) NEVER_RETURNS;
+
+
+#ifndef _WIN32  /* hooray for Unix linker hostility! */
+#undef curl_easy_setopt
+#include <dlfcn.h>
+typedef void (*CURLFN_curl_easy_cleanup)(CURL *curl);
+typedef CURL *(*CURLFN_curl_easy_init)(void);
+typedef CURLcode (*CURLFN_curl_easy_setopt)(CURL *curl, CURLoption option, ...);
+typedef CURLcode (*CURLFN_curl_easy_perform)(CURL *curl);
+typedef CURLcode (*CURLFN_curl_global_init)(long flags);
+typedef void (*CURLFN_curl_global_cleanup)(void);
+
+static CURLFN_curl_easy_cleanup CURL_curl_easy_cleanup;
+static CURLFN_curl_easy_init CURL_curl_easy_init;
+static CURLFN_curl_easy_setopt CURL_curl_easy_setopt;
+static CURLFN_curl_easy_perform CURL_curl_easy_perform;
+static CURLFN_curl_global_init CURL_curl_global_init;
+static CURLFN_curl_global_cleanup CURL_curl_global_cleanup;
+
+static void load_libcurl(void)
+{
+    #ifdef __APPLE__
+    const char *libname = "libcurl.4.dylib";
+    #else
+    const char *libname = "libcurl.so.4";
+    #endif
+
+    void *handle = dlopen(libname, RTLD_NOW | RTLD_GLOBAL);
+    if (!handle) {
+        infof("dlopen(\"%s\") failed: %s", libname, dlerror());
+        die("Failed to load libcurl library");
+    }
+    #define LOADCURLSYM(fn) \
+        if ((CURL_##fn = (CURLFN_##fn) dlsym(handle, #fn)) == NULL) { \
+            die("Failed to load libcurl symbol '" #fn "'"); \
+        }
+
+    LOADCURLSYM(curl_easy_cleanup);
+    LOADCURLSYM(curl_easy_init);
+    LOADCURLSYM(curl_easy_setopt);
+    LOADCURLSYM(curl_easy_perform);
+    LOADCURLSYM(curl_global_init);
+    LOADCURLSYM(curl_global_cleanup);
+}
+
+#define curl_easy_cleanup CURL_curl_easy_cleanup
+#define curl_easy_init CURL_curl_easy_init
+#define curl_easy_setopt CURL_curl_easy_setopt
+#define curl_easy_perform CURL_curl_easy_perform
+#define curl_global_init CURL_curl_global_init
+#define curl_global_cleanup CURL_curl_global_cleanup
+#endif
+
+
 static void die(const char *why)
 {
     infof("FAILURE: %s", why);
@@ -696,6 +749,10 @@ int main(int argc, char **argv)
         upgradeSelfAndRestart(argv[0]);
     }
 
+    #ifndef _WIN32
+    load_libcurl();
+    #endif
+
     if (curl_global_init(CURL_GLOBAL_DEFAULT) != CURLE_OK) {
         die("curl_global_init() failed!");
     }