From 1dbaf86c6b50e46c49d6fc03f60d338b68d8e8e9 Mon Sep 17 00:00:00 2001
From: Jordan Doyle <jordan@doyle.la>
Date: Thu, 21 Jul 2022 00:09:09 +0100
Subject: [PATCH] Primitive handling of info/refs & git-upload-pack

---
 Cargo.lock          |  2 ++
 Cargo.toml          |  2 ++
 src/git_cgi.rs      | 24 ++++++++++++++++++++++++
 src/main.rs         |  1 +
 src/methods/repo.rs | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 5 files changed, 93 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 0101d84..459df44 100644
--- a/Cargo.lock
+++ a/Cargo.lock
@@ -1716,9 +1716,11 @@
  "futures",
  "git2",
  "hex",
+ "httparse",
  "humantime",
  "md5",
  "moka",
+ "nom",
  "parking_lot 0.12.1",
  "path-clean",
  "rsass",
diff --git a/Cargo.toml b/Cargo.toml
index 5b6ad9d..d234d9c 100644
--- a/Cargo.toml
+++ a/Cargo.toml
@@ -16,6 +16,7 @@
 git2 = "0.14"
 hex = "0.4"
 humantime = "2.1"
+nom = "7.1"
 md5 = "0.7"
 moka = { version = "0.9", features = ["future"] }
 path-clean = "0.1"
@@ -33,6 +34,7 @@
 tracing-subscriber = "0.3"
 unix_mode = "0.1"
 uuid = { version = "1.1", features = ["v4"] }
+httparse = "1.7"
 yoke = { version = "0.6", features = ["derive"] }
 
 [build-dependencies]
diff --git a/src/git_cgi.rs b/src/git_cgi.rs
new file mode 100644
index 0000000..c0443b2 100644
--- /dev/null
+++ a/src/git_cgi.rs
@@ -1,0 +1,24 @@
+use axum::body::{boxed, Body};
+use axum::http::header::HeaderName;
+use axum::http::HeaderValue;
+use axum::response::Response;
+use std::str::FromStr;
+
+pub fn cgi_to_response(buffer: &[u8]) -> Response {
+    let mut headers = [httparse::EMPTY_HEADER; 10];
+    let (body_offset, headers) = httparse::parse_headers(buffer, &mut headers)
+        .unwrap()
+        .unwrap();
+
+    let mut response = Response::new(boxed(Body::from(buffer[body_offset..].to_vec())));
+
+    // TODO: extract status header
+    for header in headers {
+        response.headers_mut().insert(
+            HeaderName::from_str(header.name).unwrap(),
+            HeaderValue::from_bytes(header.value).unwrap(),
+        );
+    }
+
+    response
+}
diff --git a/src/main.rs b/src/main.rs
index e5babb7..e5cb6ac 100644
--- a/src/main.rs
+++ a/src/main.rs
@@ -18,6 +18,7 @@
 
 mod database;
 mod git;
+mod git_cgi;
 mod layers;
 mod methods;
 
diff --git a/src/methods/repo.rs b/src/methods/repo.rs
index 1b78848..5d6422e 100644
--- a/src/methods/repo.rs
+++ a/src/methods/repo.rs
@@ -1,20 +1,24 @@
-use std::fmt::{Display, Formatter};
 use std::{
+    fmt::{Debug, Display, Formatter},
+    io::Write,
     ops::Deref,
     path::{Path, PathBuf},
+    process::Stdio,
     sync::Arc,
 };
 
 use askama::Template;
-use axum::http::HeaderValue;
 use axum::{
+    body::HttpBody,
     extract::Query,
     handler::Handler,
     http,
+    http::HeaderValue,
     http::Request,
     response::{IntoResponse, Response},
     Extension,
 };
+use bytes::Bytes;
 use path_clean::PathClean;
 use serde::Deserialize;
 use tower::{util::BoxCloneService, Service};
@@ -50,7 +54,13 @@
 }
 
 // this is some wicked, wicked abuse of axum right here...
-pub async fn service<ReqBody: Send + 'static>(mut request: Request<ReqBody>) -> Response {
+pub async fn service<ReqBody: HttpBody + Send + Debug + 'static>(
+    mut request: Request<ReqBody>,
+) -> Response
+where
+    <ReqBody as HttpBody>::Data: Send + Sync,
+    <ReqBody as HttpBody>::Error: std::error::Error + Send + Sync,
+{
     let mut uri_parts: Vec<&str> = request
         .uri()
         .path()
@@ -63,6 +73,13 @@
 
     let mut service = match uri_parts.pop() {
         Some("about") => BoxCloneService::new(handle_about.into_service()),
+        // TODO: https://man.archlinux.org/man/git-http-backend.1.en
+        // TODO: GIT_PROTOCOL
+        Some("refs") if uri_parts.last() == Some(&"info") => {
+            uri_parts.pop();
+            BoxCloneService::new(handle_info_refs.into_service())
+        }
+        Some("git-upload-pack") => BoxCloneService::new(handle_git_upload_pack.into_service()),
         Some("refs") => BoxCloneService::new(handle_refs.into_service()),
         Some("log") => BoxCloneService::new(handle_log.into_service()),
         Some("tree") => BoxCloneService::new(handle_tree.into_service()),
@@ -210,6 +227,50 @@
         next_offset,
         branch: query.branch,
     })
+}
+
+#[derive(Deserialize)]
+pub struct SmartGitQuery {
+    service: String,
+}
+
+pub async fn handle_info_refs(
+    Extension(RepositoryPath(repository_path)): Extension<RepositoryPath>,
+    Query(query): Query<SmartGitQuery>,
+) -> Response {
+    // todo: tokio command
+    let out = std::process::Command::new("git")
+        .arg("http-backend")
+        .env("REQUEST_METHOD", "GET")
+        .env("PATH_INFO", "/info/refs")
+        .env("GIT_PROJECT_ROOT", repository_path)
+        .env("QUERY_STRING", format!("service={}", query.service))
+        .output()
+        .unwrap();
+
+    crate::git_cgi::cgi_to_response(&out.stdout)
+}
+
+pub async fn handle_git_upload_pack(
+    Extension(RepositoryPath(repository_path)): Extension<RepositoryPath>,
+    body: Bytes,
+) -> Response {
+    // todo: tokio command
+    let mut child = std::process::Command::new("git")
+        .arg("http-backend")
+        // todo: read all this from request
+        .env("REQUEST_METHOD", "POST")
+        .env("CONTENT_TYPE", "application/x-git-upload-pack-request")
+        .env("PATH_INFO", "/git-upload-pack")
+        .env("GIT_PROJECT_ROOT", repository_path)
+        .stdout(Stdio::piped())
+        .stdin(Stdio::piped())
+        .spawn()
+        .unwrap();
+    child.stdin.as_mut().unwrap().write_all(&body).unwrap();
+    let out = child.wait_with_output().unwrap();
+
+    crate::git_cgi::cgi_to_response(&out.stdout)
 }
 
 #[derive(Template)]
--
rgit 0.1.3