Add support for building with llhttp instead of http-parser

As http-parser has been unmaintained for a while [1], let's add
support for its natural replacement, llhttp.

However, as llhttp does not seem to be packaged in distros like
Debian [2], we will keep supporting building with http-parser for
time being, preferring llhttp, if it is present.

[1] nodejs/http-parser#522
[2] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=977716

.github/workflows/install-dependencies

@@ -13,7 +13,7 @@ debian:*|ubuntu:*)
     echo 'max_parallel_downloads=10' >> /etc/dnf/dnf.conf
     dnf -y clean all
     dnf -y --setopt=deltarpm=0 update
-    dnf -y install gcc meson pkgconfig libjose-devel jose http-parser-devel \
+    dnf -y install gcc meson pkgconfig libjose-devel jose llhttp-devel \
                    systemd gcovr curl socat iproute
     ;;
 

meson.build

@@ -55,13 +55,22 @@ add_project_arguments('-DVERSION="'+meson.project_version() + '"', language : 'c
 jose = dependency('jose', version: '>=8')
 a2x = find_program('a2x', required: false)
 compiler = meson.get_compiler('c')
-if not compiler.has_header('http_parser.h',args : '-I/usr/local/include')
-  error('http-parser devel files not found.')
+
+http_lib = []
+if compiler.has_header('llhttp.h', args: '-I/usr/local/include')
+  http_lib = 'llhttp'
+  add_project_arguments('-DUSE_LLHTTP', language: 'c')
+else
+  if not compiler.has_header('http_parser.h', args: '-I/usr/local/include')
+    error('neither llhttp nor http-parser devel files found.')
+  endif
+  http_lib = 'http_parser'
 endif
+
 if host_machine.system() == 'freebsd'
-  http_parser = compiler.find_library('http_parser',dirs : '/usr/local/lib')
+  http_parser = compiler.find_library(http_lib, dirs : '/usr/local/lib')
 else
-  http_parser = compiler.find_library('http_parser')
+  http_parser = compiler.find_library(http_lib)
 endif
 
 licenses = ['COPYING']

src/http.c

@@ -36,7 +36,7 @@ HTTP_METHOD_MAP(XX)
 };
 
 static int
-on_url(http_parser *parser, const char *at, size_t length)
+on_url(http_parser_t *parser, const char *at, size_t length)
 {
     struct http_state *state = parser->data;
 
@@ -51,7 +51,7 @@ on_url(http_parser *parser, const char *at, size_t length)
 }
 
 static int
-on_body(http_parser *parser, const char *at, size_t length)
+on_body(http_parser_t *parser, const char *at, size_t length)
 {
     struct http_state *state = parser->data;
 
@@ -66,7 +66,7 @@ on_body(http_parser *parser, const char *at, size_t length)
 }
 
 static int
-on_message_complete(http_parser *parser)
+on_message_complete(http_parser_t *parser)
 {
     struct http_state *state = parser->data;
     const char *addr = NULL;
@@ -132,15 +132,15 @@ on_message_complete(http_parser *parser)
     return 0;
 }
 
-const http_parser_settings http_settings = {
+const http_settings_t http_settings = {
     .on_url = on_url,
     .on_body = on_body,
     .on_message_complete = on_message_complete,
 };
 
 int
 http_reply(const char *file, int line,
-           enum http_status code, const char *fmt, ...)
+           http_status_t code, const char *fmt, ...)
 {
     const char *msg = NULL;
     va_list ap;

src/http.h

@@ -19,12 +19,39 @@
 
 #pragma once
 
-#include <http_parser.h>
 #include <sys/types.h>
 #include <regex.h>
 
+#ifdef USE_LLHTTP
+#include <llhttp.h>
+
+typedef llhttp_method_t http_method_t;
+typedef llhttp_status_t http_status_t;
+typedef llhttp_settings_t http_settings_t;
+typedef llhttp_t http_parser_t;
+#define tang_http_parser_init(parser, settings) llhttp_init(parser, HTTP_REQUEST, settings)
+#define tang_http_parser_execute(parser, settings, req, rcvd) llhttp_execute(parser, req, rcvd)
+#define tang_http_parser_errno(parser) parser.error
+#define tang_http_errno_description(parser, errno) llhttp_get_error_reason(parser)
+
+#else
+/* Legacy http-parser. */
+#include <http_parser.h>
+
+typedef enum http_method http_method_t;
+typedef enum http_status http_status_t;
+typedef http_parser_settings http_settings_t;
+typedef struct http_parser http_parser_t;
+
+#define tang_http_parser_init(parser, settings) http_parser_init(parser, HTTP_REQUEST)
+#define tang_http_parser_execute(parser, settings, req, rcvd) http_parser_execute(parser, settings, req, rcvd)
+#define tang_http_parser_errno(parser) parser.http_errno
+#define tang_http_errno_description(parser, errno) http_errno_description(errno)
+
+#endif /* USE_LLHTTP */
+
 struct http_dispatch {
-    int (*func)(enum http_method method, const char *path,
+    int (*func)(http_method_t method, const char *path,
                 const char *body, regmatch_t matches[], void *misc);
     uint64_t methods;
     size_t nmatches;
@@ -43,11 +70,11 @@ struct http_state {
     void *misc;
 };
 
-extern const http_parser_settings http_settings;
+extern const http_settings_t http_settings;
 
 int __attribute__ ((format(printf, 4, 5)))
 http_reply(const char *file, int line,
-           enum http_status code, const char *fmt, ...);
+           http_status_t code, const char *fmt, ...);
 
 #define http_reply(code, ...) \
     http_reply(__FILE__, __LINE__, code, __VA_ARGS__)

src/tangd.c

@@ -64,7 +64,7 @@ str_cleanup(char **str)
 }
 
 static int
-adv(enum http_method method, const char *path, const char *body,
+adv(http_method_t method, const char *path, const char *body,
     regmatch_t matches[], void *misc)
 {
     __attribute__((cleanup(str_cleanup))) char *adv = NULL;
@@ -101,7 +101,7 @@ adv(enum http_method method, const char *path, const char *body,
 }
 
 static int
-rec(enum http_method method, const char *path, const char *body,
+rec(http_method_t method, const char *path, const char *body,
     regmatch_t matches[], void *misc)
 {
     __attribute__((cleanup(str_cleanup))) char *enc = NULL;
@@ -197,13 +197,14 @@ static int
 process_request(const char *jwkdir, int in_fileno)
 {
     struct http_state state = { .dispatch = dispatch, .misc = (char*)jwkdir };
-    struct http_parser parser = { .data = &state };
+    http_parser_t parser;
     struct stat st = {};
     char req[4096] = {};
     size_t rcvd = 0;
     int r = 0;
 
-    http_parser_init(&parser, HTTP_REQUEST);
+    tang_http_parser_init(&parser, &http_settings);
+    parser.data = &state;
 
     if (stat(jwkdir, &st) != 0) {
         fprintf(stderr, "Error calling stat() on path: %s: %m\n", jwkdir);
@@ -224,17 +225,16 @@ process_request(const char *jwkdir, int in_fileno)
 
         rcvd += r;
 
-        r = http_parser_execute(&parser, &http_settings, req, rcvd);
-        if (parser.http_errno != 0) {
+        r = tang_http_parser_execute(&parser, &http_settings, req, rcvd);
+        if (tang_http_parser_errno(parser) != 0) {
             fprintf(stderr, "HTTP Parsing Error: %s\n",
-                    http_errno_description(parser.http_errno));
+                    tang_http_errno_description(&parser, tang_http_parser_errno(parser)));
             return EXIT_SUCCESS;
         }
 
         memmove(req, &req[r], rcvd - r);
         rcvd -= r;
     }
-
     return EXIT_SUCCESS;
 }