Rewrite gitsrht-dispatch in Go

7 files changed, 118 insertions, 69 deletions

diff --git a/gitsrht-dispatch b/gitsrht-dispatch
deleted file mode 100755
index 39e8609..0000000
--- a/gitsrht-dispatch
+++ /dev/null
@@ -1,67 +0,0 @@
-#!/usr/bin/env python3
-# AuthorizedKeysCommand=/usr/bin/git-srht-dispatch "%u" "%h" "%t" "%k"
-# AuthorizedKeysUser=root
-import sys
-import os
-try:
-    f = open("/var/log/git-srht-dispatch", "a")
-    os.close(sys.stderr.fileno())
-    os.dup2(f.fileno(), sys.stderr.fileno())
-except Exception as ex:
-    sys.stderr.write("Unable to open log for writing\n")
-    sys.stderr.write(str(ex) + "\n")
-from collections import namedtuple
-from datetime import datetime
-from pwd import getpwnam
-from grp import getgrnam
-from srht.config import cfg, cfgkeys
-
-def log(s, *args):
-    sys.stderr.write("{} {}\n".format(datetime.now().isoformat(),
-        s.format(*args) if isinstance(s, str) else str(s)))
-    sys.stderr.flush()
-log("Running git-srht-dispatch")
-
-def auth_keys_error():
-    log("This command should be run by sshd's AuthorizedKeysCommand")
-    log('AuthorizedKeysCommand={} "%u" "%h" "%t" "%k"\nAuthorizedKeysUser=root',
-        os.path.abspath(sys.argv[0]))
-    sys.exit(1)
-
-Dispatcher = namedtuple("Dispatcher", ["cmd", "uid", "gid"])
-dispatchers = list()
-
-for cmd in cfgkeys("git.sr.ht::dispatch"):
-    user = cfg("git.sr.ht::dispatch", cmd).split(":")
-    uid, gid = getpwnam(user[0]).pw_uid, getgrnam(user[-1]).gr_gid
-    dispatchers.append(Dispatcher(cmd=cmd, uid=uid, gid=gid))
-    log("registered dispatcher for {}:{}: {}", uid, gid, cmd)
-
-if len(sys.argv) != 5:
-    auth_keys_error()
-
-user = sys.argv[1]
-uid = getpwnam(user).pw_uid
-homedir = sys.argv[2]
-key_type = sys.argv[3]
-b64key = sys.argv[4]
-authorized_keys_file = "{}/.ssh/authorized_keys".format(homedir)
-
-log("authorizing user={} ({}) home={} b64key={} key_type={}",
-        user, uid, homedir, b64key, key_type)
-
-for dispatch in dispatchers:
-    if dispatch.uid == uid:
-        log("dispatching to {} with uid={}, gid={}",
-                dispatch.cmd, dispatch.uid, dispatch.gid)
-        os.setgid(dispatch.gid)
-        os.setuid(dispatch.uid)
-        os.execl(dispatch.cmd, *([dispatch.cmd] + sys.argv[1:]))
-
-log("Falling back to existing authorized keys file")
-if not os.path.exists(authorized_keys_file):
-    sys.exit(0)
-with open(authorized_keys_file, "r") as f:
-    authorized_keys = f.read()
-print(authorized_keys)
-sys.exit(0)
diff --git a/gitsrht-dispatch/.gitignore b/gitsrht-dispatch/.gitignore
new file mode 100644
index 0000000..4644fc2
--- /dev/null
+++ b/gitsrht-dispatch/.gitignore
@@ -0,0 +1 @@
+gitsrht-dispatch
diff --git a/gitsrht-dispatch/go.mod b/gitsrht-dispatch/go.mod
new file mode 100644
index 0000000..bc3195a
--- /dev/null
+++ b/gitsrht-dispatch/go.mod
@@ -0,0 +1,3 @@
+module git.sr.ht/~sircmpwn/git.sr.ht/gitsrht-dispatch
+
+require github.com/vaughan0/go-ini v0.0.0-20130923145212-a98ad7ee00ec
diff --git a/gitsrht-dispatch/go.sum b/gitsrht-dispatch/go.sum
new file mode 100644
index 0000000..bac961c
--- /dev/null
+++ b/gitsrht-dispatch/go.sum
@@ -0,0 +1,2 @@
+github.com/vaughan0/go-ini v0.0.0-20130923145212-a98ad7ee00ec h1:DGmKwyZwEB8dI7tbLt/I/gQuP559o/0FrAkHKlQM/Ks=
+github.com/vaughan0/go-ini v0.0.0-20130923145212-a98ad7ee00ec/go.mod h1:owBmyHYMLkxyrugmfwE/DLJyW8Ro9mkphwuVErQ0iUw=
diff --git a/gitsrht-dispatch/main.go b/gitsrht-dispatch/main.go
new file mode 100644
index 0000000..d7aee14
--- /dev/null
+++ b/gitsrht-dispatch/main.go
@@ -0,0 +1,111 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"io"
+	"os"
+	osuser "os/user"
+	"strconv"
+	"strings"
+	"syscall"
+
+	"github.com/vaughan0/go-ini"
+)
+
+type Dispatcher struct {
+	cmd string
+	uid int
+	gid int
+}
+
+func main() {
+	var (
+		config ini.File
+		err    error
+		logger *log.Logger
+	)
+
+	logf, err := os.OpenFile("/var/log/gitsrht-dispatch",
+		os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
+	if err != nil {
+		log.Printf("Warning: unable to open log file: %v " +
+			"(using stderr instead)", err)
+		logger = log.New(os.Stderr, "", log.LstdFlags)
+	} else {
+		logger = log.New(logf, "", log.LstdFlags)
+	}
+
+	logger.Println("Running git.sr.ht dispatch")
+
+	for _, path := range []string{"../config.ini", "/etc/sr.ht/config.ini"} {
+		config, err = ini.LoadFile(path)
+		if err == nil {
+			break
+		}
+	}
+	if err != nil {
+		logger.Fatalf("Failed to load config file: %v", err)
+	}
+
+	if len(os.Args) != 5 {
+		logger.Fatalf(`Error: This command should be run by sshd's AuthorizedKeysCommand:
+
+AuthorizedKeysCommand=%s "%%u" "%%h" "%%t" "%%k"
+AuthorizedKeysUser=root`, os.Args[0])
+	}
+
+	// Map uid -> dispatcher
+	dispatchers := make(map[int]Dispatcher)
+	for cmd, value := range config.Section("git.sr.ht::dispatch") {
+		spec := strings.Split(value, ":")
+		if len(spec) != 2 {
+			logger.Fatalf("Expected %s=user:group", cmd)
+		}
+		user, err := osuser.Lookup(spec[0])
+		if err != nil {
+			logger.Fatalf("Error looking up user %s: %v", spec[0], err)
+		}
+		group, err := osuser.LookupGroup(spec[1])
+		if err != nil {
+			logger.Fatalf("Error looking up group %s: %v", spec[1], err)
+		}
+		uid, _ := strconv.Atoi(user.Uid)
+		gid, _ := strconv.Atoi(group.Gid)
+		dispatchers[uid] = Dispatcher{cmd, uid, gid}
+		logger.Printf("Registered dispatcher for %s(%d):%s(%d): %s",
+			spec[0], uid, spec[1], gid, cmd)
+	}
+
+	var user *osuser.User
+	username := os.Args[1]
+	if user, err = osuser.Lookup(username); err != nil {
+		logger.Fatalf("Unknown user %s", username)
+	}
+	homedir := os.Args[2]
+	key_type := os.Args[3]
+	b64key := os.Args[4]
+	authorized_keys_file := fmt.Sprintf("%s/.ssh/authorized_keys", homedir)
+	uid, _ := strconv.Atoi(user.Uid)
+
+	logger.Printf("Authorizing user %s (%d); home=%s; b64key=%s; key_type=%s",
+		username, uid, homedir, b64key, key_type)
+
+	if dispatcher, ok := dispatchers[uid]; ok {
+		logger.Printf("Dispatching to %s", dispatcher.cmd)
+		syscall.Setgid(dispatcher.gid)
+		syscall.Setuid(dispatcher.uid)
+		if err := syscall.Exec(dispatcher.cmd, append([]string{
+			dispatcher.cmd,
+		}, os.Args[1:]...), os.Environ()); err != nil {
+			logger.Fatalf("Error exec'ing into %s: %v", dispatcher.cmd, err)
+		}
+	}
+
+	logger.Println("Falling back to authorized_keys file")
+	akf, err := os.Open(authorized_keys_file)
+	if err != nil {
+		logger.Fatalf("Error opening authorized_keys: %v", err)
+	}
+	io.Copy(os.Stdout, akf)
+}
diff --git a/gitsrht/service.py b/gitsrht/service.py
index e7e0cda..9e0ed86 100644
--- a/gitsrht/service.py
+++ b/gitsrht/service.py
@@ -46,7 +46,7 @@ class GitOAuthService(AbstractOAuthService):
         webhooks.update({
             webhook_url: ["ssh-key:add", "ssh-key:remove"]
         })
-        super().ensure_meta_webhooks(user, webhooks)
+        return super().ensure_meta_webhooks(user, webhooks)
 
     def lookup_or_register(self, token, token_expires, scopes):
         user = super().lookup_or_register(token, token_expires, scopes)
diff --git a/setup.py b/setup.py
index c2d7172..76a9a78 100755
--- a/setup.py
+++ b/setup.py
@@ -60,7 +60,6 @@ setup(
       ]
   },
   scripts = [
-      'gitsrht-dispatch',
       'gitsrht-keys',
       'gitsrht-migrate',
       'gitsrht-periodic',