Modulemanager: support compile-flags and always look at modulemanager block

1) We now always look at the module { } block even for unmanaged modules
   (so .c files that you put manually in src/modules/third)
2) New module::compile-flags to allow specifying compile flags / libraries / etc.

See https://www.unrealircd.org/docs/Special_module_manager_block_in_source_file

So the new stuff is:

module {
        .....
        // Simple library dependency:
        compile-flags "-lsomelib";
        // Can even use:
        compile-flags "$(mysql_config --cflags) $(mysql_config --libs)";
        .....
}

This was requested long ago by various people.

And yes, this allows shell commands to be executed if the 3rd party indicates so.
The added risk should be small, since the module could do similarly evil stuff at
runtime, unless you compile with a totally different user compared to runtime.
The most common case where compile time vs runtime is completely different would
be for packaging (deb/rpm/whatever), which presumably ship with zero 3rd party
modules, so then there shouldn't be a concern either.

Obviously, for 3rd party modules in the unrealircd-contrib repository we screen
modules to make sure they don't do anything evil: "No malicious code or intent"
in https://www.unrealircd.org/docs/Rules_for_3rd_party_modules_in_unrealircd-contrib

src/modulemanager.c

@@ -27,6 +27,7 @@ struct ManagedModule
 	char *min_unrealircd_version;
 	char *max_unrealircd_version;
 	char *description;
+	char *compile_flags;
 	MultiLine *post_install_text;
 	int unmanaged;
 };
@@ -131,6 +132,11 @@ int mm_module_file_config(ManagedModule *m, ConfigEntry *ce)
 			CheckNull(cep);
 			safe_strdup(m->max_unrealircd_version, cep->value);
 		}
+		else if (!strcmp(cep->name, "compile-flags"))
+		{
+			CheckNull(cep);
+			safe_strdup(m->compile_flags, cep->value);
+		}
 		else if (!strcmp(cep->name, "post-install-text"))
 		{
 			if (cep->items)
@@ -199,7 +205,7 @@ int mm_parse_module_file(ManagedModule *m, char *buf, unsigned int line_offset)
 }
 
 #define MODULECONFIGBUFFER 16384
-ManagedModule *mm_parse_module_c_file(char *modulename, char *fname)
+ManagedModule *mm_parse_module_c_file(char *modulename, char *fname, int silent)
 {
 	char buf[1024];
 	FILE *fd;
@@ -310,8 +316,11 @@ ManagedModule *mm_parse_module_c_file(char *modulename, char *fname)
 
 	if (!*moduleconfig)
 	{
-		fprintf(stderr, "ERROR: Module does not contain module config data (<<<MODULE MANAGER START>>>)\n"
-		                "This means it is not meant to be managed by the module manager\n");
+		if (!silent)
+		{
+			fprintf(stderr, "ERROR: Module does not contain module config data (<<<MODULE MANAGER START>>>)\n"
+					"This means it is not meant to be managed by the module manager\n");
+		}
 		safe_free(moduleconfig);
 		return NULL;
 	}
@@ -377,6 +386,7 @@ void free_managed_module(ManagedModule *m)
 	safe_free(m->min_unrealircd_version);
 	safe_free(m->max_unrealircd_version);
 	safe_free(m->description);
+	safe_free(m->compile_flags);
 	freemultiline(m->post_install_text);
 	safe_free(m);
 }
@@ -469,6 +479,11 @@ ManagedModule *mm_repo_module_config(char *repo_url, ConfigEntry *ce)
 			CheckNull(cep);
 			safe_strdup(m->max_unrealircd_version, cep->value);
 		}
+		else if (!strcmp(cep->name, "compile-flags"))
+		{
+			CheckNull(cep);
+			safe_strdup(m->compile_flags, cep->value);
+		}
 		else if (!strcmp(cep->name, "description"))
 		{
 			CheckNull(cep);
@@ -884,6 +899,24 @@ void mm_list(char *searchname)
 	print_documentation();
 }
 
+
+
+/* Helper to get compile flags. Do not return NULL but "" here if none */
+const char *mm_get_compile_flags(ManagedModule *m)
+{
+	static char retbuf[512];
+	char *flags;
+
+	if (!m->compile_flags)
+		return "";
+
+	/* Simple as-is for now */
+	flags = m->compile_flags;
+
+	unreal_add_quotes_r(flags, retbuf, sizeof(retbuf)-1);
+	return retbuf;
+}
+
 int mm_compile(ManagedModule *m, const char *tmpfile, int test, int upgrade)
 {
 	char newpath[512];
@@ -918,9 +951,10 @@ int mm_compile(ManagedModule *m, const char *tmpfile, int test, int upgrade)
 		return 0;
 
 	snprintf(cmd, sizeof(cmd),
-	         "cd \"%s\"; $MAKE custommodule MODULEFILE=\"%s\"",
+	         "cd \"%s\"; $MAKE custommodule MODULEFILE=\"%s\" EXLIBS=\"%s\"",
 	         BUILDDIR,
-	         filename_strip_suffix(basename, ".c")
+	         filename_strip_suffix(basename, ".c"),
+	         mm_get_compile_flags(m)
 	         );
 	fd = popen(cmd, "r");
 	if (!fd)
@@ -949,12 +983,10 @@ int mm_compile(ManagedModule *m, const char *tmpfile, int test, int upgrade)
 		return 1;
 
 	fprintf(stderr, "ERROR: Compile errors encountered while compiling module '%s'\n", m->name);
-	if (!m->unmanaged)
+	if (m->author && m->troubleshooting)
 	{
 		fprintf(stderr, "You are suggested to contact the author (%s) of this module %s:\n%s\n",
 	                m->author, m->name, m->troubleshooting);
-	} else {
-		/* Uh yeah, not much we can say? */
 	}
 
 	return 0;
@@ -978,20 +1010,25 @@ int mm_compile_all(int argc, char *args[])
 			char *fname = dir->d_name;
 			if (filename_has_suffix(fname, ".c"))
 			{
+				char fullpath[512];
 				char modname[512];
-				//char sofile[512];
 				char *p;
 				char simplename[512];
 
+				snprintf(fullpath, sizeof(fullpath), "%s/%s", dirname, fname);
 				strlcpy(simplename, filename_strip_suffix(fname, ".c"), sizeof(simplename));
 				snprintf(modname, sizeof(modname), "third/%s", simplename);
 
 				if (!(m = mm_find_module(modname)))
 				{
-					/* Untracked module: create a simple struct */
-					m = safe_alloc(sizeof(ManagedModule));
+					m = mm_parse_module_c_file(modname, fullpath, 1);
+					if (!m)
+					{
+						/* No module manager block, create a fake one: */
+						m = safe_alloc(sizeof(ManagedModule));
+						safe_strdup(m->name, modname);
+					}
 					m->unmanaged = 1;
-					safe_strdup(m->name, modname);
 					n = mm_compile(m, NULL, 0, 0);
 					safe_free_managed_module(m);
 				} else {
@@ -1339,6 +1376,8 @@ void print_md_block(FILE *fdo, ManagedModule *m)
 	fprintf(fdo, "\tmin-unrealircd-version \"%s\";\n", unreal_add_quotes(m->min_unrealircd_version));
 	if (m->max_unrealircd_version)
 		fprintf(fdo, "\tmax-unrealircd-version \"%s\";\n", unreal_add_quotes(m->max_unrealircd_version));
+	if (m->compile_flags)
+		fprintf(fdo, "\tcompile-flags \"%s\";\n", unreal_add_quotes(m->compile_flags));
 	if (m->post_install_text)
 	{
 		MultiLine *l;
@@ -1412,7 +1451,7 @@ void mm_generate_repository(int argc, char *args[])
 			snprintf(fullname, sizeof(fullname), "%s/%s", dirname, fname);
 			snprintf(modname, sizeof(modname), "third/%s", filename_strip_suffix(fname, ".c"));
 			printf("Processing: %s\n", modname);
-			m = mm_parse_module_c_file(modname, fullname);
+			m = mm_parse_module_c_file(modname, fullname, 0);
 			if (!m)
 			{
 				fprintf(stderr, "WARNING: Skipping module '%s' due to errors\n", modname);
@@ -1456,7 +1495,7 @@ void mm_parse_c_file(int argc, char *args[])
 
 	snprintf(modname, sizeof(modname), "third/%s", filename_strip_suffix(basename, ".c"));
 	printf("Processing: %s\n", modname);
-	m = mm_parse_module_c_file(modname, fullname);
+	m = mm_parse_module_c_file(modname, fullname, 0);
 	if (!m)
 	{
 		fprintf(stderr, "Errors encountered. See above\n");