services/arv-git-httpd/git_handler.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package main
   6
   7 import (
   8         "log"
   9         "net"
  10         "net/http"
  11         "net/http/cgi"
  12         "os"
  13 )
  14
  15 // gitHandler is an http.Handler that invokes git-http-backend (or
  16 // whatever backend is configured) via CGI, with appropriate
  17 // environment variables in place for git-http-backend or
  18 // gitolite-shell.
  19 type gitHandler struct {
  20         cgi.Handler
  21 }
  22
  23 func newGitHandler() http.Handler {
  24         const glBypass = "GL_BYPASS_ACCESS_CHECKS"
  25         const glHome = "GITOLITE_HTTP_HOME"
  26         var env []string
  27         path := os.Getenv("PATH")
  28         if theConfig.GitoliteHome != "" {
  29                 env = append(env,
  30                         glHome+"="+theConfig.GitoliteHome,
  31                         glBypass+"=1")
  32                 path = path + ":" + theConfig.GitoliteHome + "/bin"
  33         } else if home, bypass := os.Getenv(glHome), os.Getenv(glBypass); home != "" || bypass != "" {
  34                 env = append(env, glHome+"="+home, glBypass+"="+bypass)
  35                 log.Printf("DEPRECATED: Passing through %s and %s environment variables. Use GitoliteHome configuration instead.", glHome, glBypass)
  36         }
  37         env = append(env,
  38                 "GIT_PROJECT_ROOT="+theConfig.RepoRoot,
  39                 "GIT_HTTP_EXPORT_ALL=",
  40                 "SERVER_ADDR="+theConfig.Listen,
  41                 "PATH="+path)
  42         return &gitHandler{
  43                 Handler: cgi.Handler{
  44                         Path: theConfig.GitCommand,
  45                         Dir:  theConfig.RepoRoot,
  46                         Env:  env,
  47                         Args: []string{"http-backend"},
  48                 },
  49         }
  50 }
  51
  52 func (h *gitHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
  53         remoteHost, remotePort, err := net.SplitHostPort(r.RemoteAddr)
  54         if err != nil {
  55                 log.Printf("Internal error: SplitHostPort(r.RemoteAddr==%q): %s", r.RemoteAddr, err)
  56                 w.WriteHeader(http.StatusInternalServerError)
  57                 return
  58         }
  59
  60         // Copy the wrapped cgi.Handler, so these request-specific
  61         // variables don't leak into the next request.
  62         handlerCopy := h.Handler
  63         handlerCopy.Env = append(handlerCopy.Env,
  64                 // In Go1.5 we can skip this, net/http/cgi will do it for us:
  65                 "REMOTE_HOST="+remoteHost,
  66                 "REMOTE_ADDR="+remoteHost,
  67                 "REMOTE_PORT="+remotePort,
  68                 // Ideally this would be a real username:
  69                 "REMOTE_USER="+r.RemoteAddr,
  70         )
  71         handlerCopy.ServeHTTP(w, r)
  72 }