binary lookup path

client/driver/exec.go

@@ -112,7 +112,7 @@ func (d *ExecDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 	ps, err := exec.LaunchCmd(&executor.ExecCommand{Cmd: command, Args: driverConfig.Args}, executorCtx)
 	if err != nil {
 		pluginClient.Kill()
-		return nil, fmt.Errorf("error starting process via the plugin: %v", err)
+		return nil, err
 	}
 	d.logger.Printf("[DEBUG] driver.exec: started process via plugin with pid: %v", ps.Pid)
 

client/driver/executor/executor.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"runtime"
 	"strings"
 	"sync"
@@ -145,20 +146,36 @@ func (e *UniversalExecutor) LaunchCmd(command *ExecCommand, ctx *ExecutorContext
 	e.cmd.Stderr = lre
 	e.lre = lre
 
-	// setting the env, path and args for the command
 	e.ctx.TaskEnv.Build()
-	e.cmd.Env = ctx.TaskEnv.EnvList()
-	e.cmd.Path = ctx.TaskEnv.ReplaceEnv(command.Cmd)
-	e.cmd.Args = append([]string{e.cmd.Path}, ctx.TaskEnv.ParseAndReplace(command.Args)...)
 
-	// Ensure that the binary being started is executable.
-	if err := e.makeExecutable(e.cmd.Path); err != nil {
+	// Look up the binary path and make it executable
+	absPath, err := e.lookupBin(ctx.TaskEnv.ReplaceEnv(command.Cmd))
+	if err != nil {
 		return nil, err
 	}
 
-	// starting the process
+	if err := e.makeExecutable(absPath); err != nil {
+		return nil, err
+	}
+
+	// Determine the path to run as it may have to be relative to the chroot.
+	path := absPath
+	if e.ctx.FSIsolation {
+		rel, err := filepath.Rel(e.taskDir, absPath)
+		if err != nil {
+			return nil, err
+		}
+		path = rel
+	}
+
+	// Set the commands arguments
+	e.cmd.Path = path
+	e.cmd.Args = append([]string{path}, ctx.TaskEnv.ParseAndReplace(command.Args)...)
+	e.cmd.Env = ctx.TaskEnv.EnvList()
+
+	// Start the process
 	if err := e.cmd.Start(); err != nil {
-		return nil, fmt.Errorf("error starting command: %v", err)
+		return nil, err
 	}
 	go e.wait()
 	ic := &cstructs.IsolationConfig{Cgroup: e.groups}
@@ -279,8 +296,36 @@ func (e *UniversalExecutor) configureTaskDir() error {
 	return nil
 }
 
-// makeExecutablePosix makes the given file executable for root,group,others.
-func (e *UniversalExecutor) makeExecutablePosix(binPath string) error {
+// lookupBin looks for path to the binary to run by looking for the binary in
+// the following locations, in-order: task/local/, task/, based on host $PATH.
+// The return path is absolute.
+func (e *UniversalExecutor) lookupBin(bin string) (string, error) {
+	// Check in the local directory
+	local := filepath.Join(e.taskDir, allocdir.TaskLocal, bin)
+	if _, err := os.Stat(local); err == nil {
+		return local, nil
+	}
+
+	// Check at the root of the task's directory
+	root := filepath.Join(e.taskDir, bin)
+	if _, err := os.Stat(root); err == nil {
+		return root, nil
+	}
+
+	// Check the $PATH
+	if host, err := exec.LookPath(bin); err == nil {
+		return host, nil
+	}
+
+	return "", fmt.Errorf("binary %q could not be found", bin)
+}
+
+// makeExecutable makes the given file executable for root,group,others.
+func (e *UniversalExecutor) makeExecutable(binPath string) error {
+	if runtime.GOOS == "windows" {
+		return nil
+	}
+
 	fi, err := os.Stat(binPath)
 	if err != nil {
 		if os.IsNotExist(err) {

client/driver/executor/executor_basic.go

@@ -2,25 +2,7 @@
 
 package executor
 
-import (
-	"path/filepath"
-	"runtime"
-
-	cgroupConfig "github.com/opencontainers/runc/libcontainer/configs"
-)
-
-func (e *UniversalExecutor) makeExecutable(binPath string) error {
-	if runtime.GOOS == "windows" {
-		return nil
-	}
-
-	path := binPath
-	if !filepath.IsAbs(binPath) {
-		// The path must be relative the allocations directory.
-		path = filepath.Join(e.taskDir, binPath)
-	}
-	return e.makeExecutablePosix(path)
-}
+import cgroupConfig "github.com/opencontainers/runc/libcontainer/configs"
 
 func (e *UniversalExecutor) configureChroot() error {
 	return nil

client/driver/executor/executor_linux.go

@@ -36,18 +36,6 @@ var (
 	}
 )
 
-func (e *UniversalExecutor) makeExecutable(binPath string) error {
-	path := binPath
-	if e.ctx.FSIsolation {
-		// The path must be relative the chroot
-		path = filepath.Join(e.taskDir, binPath)
-	} else if !filepath.IsAbs(binPath) {
-		// The path must be relative the allocations directory.
-		path = filepath.Join(e.taskDir, binPath)
-	}
-	return e.makeExecutablePosix(path)
-}
-
 // configureIsolation configures chroot and creates cgroups
 func (e *UniversalExecutor) configureIsolation() error {
 	if e.ctx.FSIsolation {

client/driver/executor/executor_test.go

@@ -218,3 +218,38 @@ func TestExecutor_Start_Kill(t *testing.T) {
 		t.Fatalf("Command output incorrectly: want %v; got %v", expected, act)
 	}
 }
+
+func TestExecutor_MakeExecutable(t *testing.T) {
+	// Create a temp file
+	f, err := ioutil.TempFile("", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	defer os.Remove(f.Name())
+
+	// Set its permissions to be non-executable
+	f.Chmod(os.FileMode(0610))
+
+	// Make a fake exececutor
+	ctx := testExecutorContext(t)
+	defer ctx.AllocDir.Destroy()
+	executor := NewExecutor(log.New(os.Stdout, "", log.LstdFlags))
+
+	err = executor.(*UniversalExecutor).makeExecutable(f.Name())
+	if err != nil {
+		t.Fatalf("makeExecutable() failed: %v", err)
+	}
+
+	// Check the permissions
+	stat, err := f.Stat()
+	if err != nil {
+		t.Fatalf("Stat() failed: %v", err)
+	}
+
+	act := stat.Mode().Perm()
+	exp := os.FileMode(0755)
+	if act != exp {
+		t.Fatalf("expected permissions %v; got %v", err)
+	}
+}

client/driver/java.go

@@ -172,7 +172,7 @@ func (d *JavaDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 	ps, err := execIntf.LaunchCmd(&executor.ExecCommand{Cmd: absPath, Args: args}, executorCtx)
 	if err != nil {
 		pluginClient.Kill()
-		return nil, fmt.Errorf("error starting process via the plugin: %v", err)
+		return nil, err
 	}
 	d.logger.Printf("[DEBUG] driver.java: started process with pid: %v", ps.Pid)
 

client/driver/qemu.go

@@ -200,7 +200,7 @@ func (d *QemuDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle,
 	ps, err := exec.LaunchCmd(&executor.ExecCommand{Cmd: args[0], Args: args[1:]}, executorCtx)
 	if err != nil {
 		pluginClient.Kill()
-		return nil, fmt.Errorf("error starting process via the plugin: %v", err)
+		return nil, err
 	}
 	d.logger.Printf("[INFO] Started new QemuVM: %s", vmID)
 

client/driver/raw_exec.go

@@ -105,7 +105,7 @@ func (d *RawExecDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandl
 	ps, err := exec.LaunchCmd(&executor.ExecCommand{Cmd: command, Args: driverConfig.Args}, executorCtx)
 	if err != nil {
 		pluginClient.Kill()
-		return nil, fmt.Errorf("error starting process via the plugin: %v", err)
+		return nil, err
 	}
 	d.logger.Printf("[DEBUG] driver.raw_exec: started process with pid: %v", ps.Pid)
 

client/driver/rkt.go

@@ -249,7 +249,7 @@ func (d *RktDriver) Start(ctx *ExecContext, task *structs.Task) (DriverHandle, e
 	ps, err := execIntf.LaunchCmd(&executor.ExecCommand{Cmd: absPath, Args: cmdArgs}, executorCtx)
 	if err != nil {
 		pluginClient.Kill()
-		return nil, fmt.Errorf("error starting process via the plugin: %v", err)
+		return nil, err
 	}
 
 	d.logger.Printf("[DEBUG] driver.rkt: started ACI %q with: %v", img, cmdArgs)