Improve and add comments

[safcm/safcm.git] / rpc / dial.go

diff --git a/rpc/dial.go b/rpc/dial.go
index d8a63386333d2c76c27affca33418d3378bcc4dc..0782ab08e617933e4e2c369651253d11324e355f 100644 (file)
--- a/rpc/dial.go
+++ b/rpc/dial.go
@@ -32,7 +32,7 @@ import (
        "ruderich.org/simon/safcm/remote"
 )
 
-func (c *Conn) DialSSH(user, host string) error {
+func (c *Conn) DialSSH(user, host, sshConfig string) error {
        if c.events == nil {
                return fmt.Errorf("cannot reuse Conn")
        }
@@ -48,8 +48,14 @@ func (c *Conn) DialSSH(user, host string) error {
                // Help debugging by showing executed shell commands
                opts += "x"
        }
-       c.cmd = exec.Command("ssh", remote, "/bin/sh", opts)
-       c.remote = remote
+
+       c.sshRemote = remote
+       if sshConfig != "" {
+               c.sshOpts = append(c.sshOpts, "-F", sshConfig)
+       }
+       c.cmd = exec.Command("ssh",
+               append(append([]string{}, c.sshOpts...),
+                       c.sshRemote, "/bin/sh", opts)...)
 
        stdin, err := c.cmd.StdinPipe()
        if err != nil {
@@ -135,13 +141,13 @@ compat_sha512sum() {
        //
        // The target directory must no permit other users to delete our files
        // or symlink attacks and arbitrary code execution is possible. For
-       // /tmp this is guaranteed by the sticky bit. Make sure it has the
-       // proper permissions.
+       // /tmp this is guaranteed by the sticky bit. The code verifies the
+       // directory has the proper permissions.
        //
        // We cannot use `test -f && test -O` because this is open to TOCTOU
        // attacks. `stat` gives use the full file state. If the file is owned
-       // by us and not a symlink then it's safe to use (assuming sticky or
-       // directory not writable by others).
+       // by us and not a symlink then it's safe to use (assuming sticky
+       // directory or directory not writable by others).
        //
        // `test -e` is only used to prevent error messages if the file
        // doesn't exist. It does not guard against any races.
@@ -251,12 +257,14 @@ f
                path = strings.TrimSuffix(path, "\n")
 
                c.debugf("DialSSH: uploading new remote to %q at %q",
-                       c.remote, path)
+                       c.sshRemote, path)
 
-               cmd := exec.Command("ssh", c.remote,
-                       fmt.Sprintf("cat > %q", path))
+               cmd := exec.Command("ssh",
+                       append(append([]string{}, c.sshOpts...),
+                               c.sshRemote,
+                               fmt.Sprintf("cat > %q", path))...)
                cmd.Stdin = bytes.NewReader(helper)
-               err = c.handleStderrAsEvents(cmd)
+               err = c.handleStderrAsEvents(cmd) // cmd.Stderr
                if err != nil {
                        return err
                }