TCC patch that enables including files via HTTPS using CURL

0001-Make-it-possible-to-include-files-over-https.patch

From 84c42091cbae3735c52e895221f3f95a87155756 Mon Sep 17 00:00:00 2001
From: rexim <[email protected]>
Date: Wed, 30 Jun 2021 20:43:47 +0700
Subject: [PATCH] Make it possible to include files over https

---
 Makefile |  2 +-
 tcc.c    |  5 +++++
 tccpp.c  | 43 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 3ae466f..98de4ce 100644
--- a/Makefile
+++ b/Makefile
@@ -30,7 +30,7 @@ ifdef CONFIG_WIN32
  CFGWIN = -win
  NATIVE_TARGET = $(ARCH)-win$(if $(findstring arm,$(ARCH)),ce,32)
 else
- LIBS=-lm
+ LIBS=-lm -lcurl
  ifneq ($(CONFIG_ldl),no)
   LIBS+=-ldl
  endif
diff --git a/tcc.c b/tcc.c
index cd887d1..7a5e53f 100644
--- a/tcc.c
+++ b/tcc.c
@@ -23,6 +23,7 @@
 # include "libtcc.c"
 #endif
 #include "tcctools.c"
+#include <curl/curl.h>
 
 static const char help[] =
     "Tiny C Compiler "TCC_VERSION" - Copyright (C) 2001-2006 Fabrice Bellard\n"
@@ -257,6 +258,10 @@ redo:
     s = tcc_new();
     opt = tcc_parse_args(s, &argc, &argv, 1);
 
+    if (curl_global_init(CURL_GLOBAL_DEFAULT) != 0) {
+        tcc_error("Could not initialize Global cURL context. (Yes, your C compiler is using curl Kappa)");
+    }
+
     if ((n | t) == 0) {
         if (opt == OPT_HELP)
             return printf(help), 1;
diff --git a/tccpp.c b/tccpp.c
index 76f9e42..0b86a41 100644
--- a/tccpp.c
+++ b/tccpp.c
@@ -20,6 +20,8 @@
 
 #include "tcc.h"
 
+#include <curl/curl.h>
+
 /********************************************************/
 /* global variables */
 
@@ -1798,6 +1800,47 @@ ST_FUNC void preprocess(int is_bof)
 	    buf[len - 2] = '\0';
         }
 
+        // Hacked by https://tsoding.github.io/
+        // Available to everyone under Public Domain
+        if (strncmp("https://", buf, 8) == 0) {
+            CURLU *url = curl_url();
+            if (curl_url_set(url, CURLUPART_URL, buf, 0)) {
+                tcc_error("Could not parse the include URL");
+            }
+
+            char *path;
+            if (curl_url_get(url, CURLUPART_PATH, &path, 0)) {
+                tcc_error("Could not extract path from the include URL");
+            }
+
+            const char *file_name = tcc_basename(path);
+
+            CURL *curl = curl_easy_init();
+            if (curl == NULL) {
+                tcc_error("Could not initialize cURL context");
+            }
+
+            FILE *download_file = fopen(file_name, "w");
+            if (download_file == NULL) {
+                tcc_error("Could not open file %s: %s", file_name, strerror(errno));
+            }
+
+            curl_easy_setopt(curl, CURLOPT_URL, buf);
+            curl_easy_setopt(curl, CURLOPT_WRITEDATA, download_file);
+            CURLcode res = curl_easy_perform(curl);
+            if (res != CURLE_OK) {
+                tcc_error("Could not download %s: %s\n", buf, curl_easy_strerror(res));
+            }
+
+            strncpy(buf, file_name, sizeof(buf) - 1);
+
+            curl_free(path);
+            curl_url_cleanup(url);
+            curl_easy_cleanup(curl);
+
+            fclose(download_file);
+        }
+
         if (s1->include_stack_ptr >= s1->include_stack + INCLUDE_STACK_SIZE)
             tcc_error("#include recursion too deep");
         /* store current file in stack, but increment stack later below */
-- 
2.20.1

@rexim
Hi there .
FYI : another approach to SUBJ: To use LD_PRELOAD + dll with hookup open/close/stat libc functions . And replace open() library-call with opened "curl " subprocess file-descriptor .
eg:
$LD_PRELOAD=./libhook_library.so tcc -run mysource_with_https_includes.c

The flow
-: tcc/gcc tries to open() filename "https://xxxxx/pppp.h"
-: library implements open() function -- "see" filename contains "https://" -- and instead of open file , returns file descriptor like : return fileno( popen("curl url ", "r") ).
(other filenames (not contains "https://") - just bypass to original libc open() call )

Example : (tested with tcc/ tcc -run/ gcc / clang ) .
https://github.com/alexander-vla/hook_up_open_curl/blob/main/libinclude_hook.c

from video
https://www.youtube.com/watch?v=4vSyqK3SK-0

@theoparis Hi. I have made some changes, and now it should be able to work on the latest TCC.
https://gist.github.com/13m0n4de/84912522cce6db31da069baf1add04f8