support an overridden "cmd" for CGIs

4 files changed, 33 insertions, 23 deletions

diff --git a/contrib/cgi/cgi.go b/contrib/cgi/cgi.go
index 48af04a..b7dd14a 100644
--- a/contrib/cgi/cgi.go
+++ b/contrib/cgi/cgi.go
@@ -11,6 +11,7 @@ import (
 	"net"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"strings"
 
 	sr "tildegit.org/tjp/sliderule"
@@ -88,16 +89,9 @@ func RunCGI(
 	request *sr.Request,
 	executable string,
 	pathInfo string,
+	workdir string,
 	stderr io.Writer,
 ) (*bytes.Buffer, int, error) {
-	pathSegments := strings.Split(executable, "/")
-
-	dirPath := "."
-	if len(pathSegments) > 1 {
-		dirPath = strings.Join(pathSegments[:len(pathSegments)-1], "/")
-	}
-	basename := pathSegments[len(pathSegments)-1]
-
 	infoLen := len(pathInfo)
 	if pathInfo == "/" {
 		infoLen = 0
@@ -106,9 +100,14 @@ func RunCGI(
 	scriptName := request.Path[:len(request.Path)-infoLen]
 	scriptName = strings.TrimSuffix(scriptName, "/")
 
-	cmd := exec.CommandContext(ctx, "./"+basename)
+	execpath, err := filepath.Abs(executable)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	cmd := exec.CommandContext(ctx, execpath)
 	cmd.Env = prepareCGIEnv(ctx, request, scriptName, pathInfo)
-	cmd.Dir = dirPath
+	cmd.Dir = workdir
 
 	if body, ok := request.Meta.(io.Reader); ok {
 		cmd.Stdin = body
@@ -117,8 +116,7 @@ func RunCGI(
 	cmd.Stdout = responseBuffer
 	cmd.Stderr = stderr
 
-	err := cmd.Run()
-	if err != nil {
+	if err := cmd.Run(); err != nil {
 		var exErr *exec.ExitError
 		if errors.As(err, &exErr) {
 			return responseBuffer, exErr.ExitCode(), nil
diff --git a/contrib/cgi/cgi_test.go b/contrib/cgi/cgi_test.go
index 5469fc8..e5fb306 100644
--- a/contrib/cgi/cgi_test.go
+++ b/contrib/cgi/cgi_test.go
@@ -21,7 +21,7 @@ func TestCGIDirectory(t *testing.T) {
 	tlsconf, err := gemini.FileTLS("testdata/server.crt", "testdata/server.key")
 	require.Nil(t, err)
 
-	handler := cgi.GeminiCGIDirectory("./testdata", "/cgi-bin")
+	handler := cgi.GeminiCGIDirectory("./testdata", "/cgi-bin", "")
 	server, err := gemini.NewServer(context.Background(), "localhost", "tcp", "127.0.0.1:0", handler, nil, tlsconf)
 	require.Nil(t, err)
 
diff --git a/contrib/cgi/gemini.go b/contrib/cgi/gemini.go
index 3ad407d..0aa3044 100644
--- a/contrib/cgi/gemini.go
+++ b/contrib/cgi/gemini.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"path/filepath"
 	"strings"
 
 	sr "tildegit.org/tjp/sliderule"
@@ -17,23 +18,28 @@ import (
 // a request for /foo/bar/baz can also run an executable found at /foo or  /foo/bar. In
 // such a case the PATH_INFO environment variable will include the remaining portion of
 // the URI path.
-func GeminiCGIDirectory(fsroot, urlroot string) sr.Handler {
+func GeminiCGIDirectory(fsroot, urlroot, cmd string) sr.Handler {
 	fsroot = strings.TrimRight(fsroot, "/")
 	return sr.HandlerFunc(func(ctx context.Context, request *sr.Request) *sr.Response {
 		if !strings.HasPrefix(request.Path, urlroot) {
 			return nil
 		}
 
-		filepath, pathinfo, err := ResolveCGI(request.Path[len(urlroot):], fsroot)
+		execpath, pathinfo, err := ResolveCGI(request.Path[len(urlroot):], fsroot)
 		if err != nil {
 			return gemini.Failure(err)
 		}
-		if filepath == "" {
+		if execpath == "" {
 			return nil
 		}
+		workdir := filepath.Dir(execpath)
+
+		if cmd != "" {
+			execpath = cmd
+		}
 
 		stderr := &bytes.Buffer{}
-		stdout, exitCode, err := RunCGI(ctx, request, filepath, pathinfo, stderr)
+		stdout, exitCode, err := RunCGI(ctx, request, execpath, pathinfo, workdir, stderr)
 		if err != nil {
 			return gemini.Failure(err)
 		}
diff --git a/contrib/cgi/gopher.go b/contrib/cgi/gopher.go
index bb3e73e..7067a6d 100644
--- a/contrib/cgi/gopher.go
+++ b/contrib/cgi/gopher.go
@@ -21,7 +21,7 @@ import (
 // a request for /foo/bar/baz can also run an executable found at /foo or  /foo/bar. In
 // such a case the PATH_INFO environment variable will include the remaining portion of
 // the URI path.
-func GopherCGIDirectory(fsroot, urlroot string, settings *gophermap.FileSystemSettings) sr.Handler {
+func GopherCGIDirectory(fsroot, urlroot, cmd string, settings *gophermap.FileSystemSettings) sr.Handler {
 	if settings == nil || !settings.Exec {
 		return sr.HandlerFunc(func(ctx context.Context, request *sr.Request) *sr.Response { return nil })
 	}
@@ -41,12 +41,12 @@ func GopherCGIDirectory(fsroot, urlroot string, settings *gophermap.FileSystemSe
 			return nil
 		}
 
-		return runGopherCGI(ctx, request, fullpath, pathinfo, *settings)
+		return runGopherCGI(ctx, request, fullpath, pathinfo, cmd, *settings)
 	})
 }
 
 // ExecGopherMaps runs any gophermaps
-func ExecGopherMaps(fsroot, urlroot string, settings *gophermap.FileSystemSettings) sr.Handler {
+func ExecGopherMaps(fsroot, urlroot, cmd string, settings *gophermap.FileSystemSettings) sr.Handler {
 	if settings == nil || !settings.Exec {
 		return sr.HandlerFunc(func(ctx context.Context, request *sr.Request) *sr.Response { return nil })
 	}
@@ -85,7 +85,7 @@ func ExecGopherMaps(fsroot, urlroot string, settings *gophermap.FileSystemSettin
 				if !m.IsRegular() || m&5 != 5 {
 					continue
 				}
-				return runGopherCGI(ctx, request, fpath, "/", *settings)
+				return runGopherCGI(ctx, request, fpath, "/", cmd, *settings)
 			}
 
 			return nil
@@ -96,7 +96,7 @@ func ExecGopherMaps(fsroot, urlroot string, settings *gophermap.FileSystemSettin
 			return nil
 		}
 
-		return runGopherCGI(ctx, request, fullpath, "/", *settings)
+		return runGopherCGI(ctx, request, fullpath, "/", cmd, *settings)
 	})
 }
 
@@ -105,10 +105,16 @@ func runGopherCGI(
 	request *sr.Request,
 	fullpath string,
 	pathinfo string,
+	cmd string,
 	settings gophermap.FileSystemSettings,
 ) *sr.Response {
+	workdir := filepath.Dir(fullpath)
+	if cmd != "" {
+		fullpath = cmd
+	}
+
 	stderr := &bytes.Buffer{}
-	stdout, exitCode, err := RunCGI(ctx, request, fullpath, pathinfo, stderr)
+	stdout, exitCode, err := RunCGI(ctx, request, fullpath, pathinfo, workdir, stderr)
 	if err != nil {
 		return gopher.Error(err).Response()
 	}