fix: oci: set default PATH if image does not

OCI images almost always set `PATH` in their config. However, some don't. Most recently, `docker://busybox:latest` changed and the new version: * Doesn't set `PATH` in its config. * Has a CMD of `sh` which has to be found on a `PATH`. Singularity's OCI mode was failing to find `sh`. Other runtimes set a default `PATH` in the container, so running `busybox:latest` still works. This PR ensures we set a default `PATH` in the container where the image does not provide one. Fixes #2721
sylabs · Mar 6, 2024 · 5ad6418 · 5ad6418
1 parent ac6b804
commit 5ad6418
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # SingularityCE Changelog
 
+## Change Since Last Release
+
+### Bug Fixes
+
+- Set default `PATH` in container run in OCI-Mode when image does not set `PATH`.
+
 ## 4.1.2 \[2024-03-05\]
 
 ### Bug Fixes

diff --git a/internal/pkg/runtime/launcher/oci/process_linux.go b/internal/pkg/runtime/launcher/oci/process_linux.go
@@ -376,16 +376,20 @@ func (l *Launcher) getProcessEnv(imageSpec imgspecv1.Image, hostEnv []string, us
 }
 
 func setOCIPath(g *generate.Generator, prependPath, path, appendPath string) {
+	// If we have no PATH at this point, then the image didn't define one, and
+	// the user didn't specify a full PATH override. We need to use a default,
+	// to find bare `CMD`s e.g. issue #2721.
+	if path == "" {
+		path = env.DefaultPath
+	}
 	// Compute and set optionally APPEND-ed / PREPEND-ed PATH.
 	if appendPath != "" {
 		path = strings.TrimSuffix(path, ":") + ":" + appendPath
 	}
 	if prependPath != "" {
 		path = prependPath + ":" + strings.TrimPrefix(path, ":")
 	}
-	if path != "" {
-		g.AddProcessEnv("PATH", path)
-	}
+	g.AddProcessEnv("PATH", path)
 }
 
 func setNativePath(g *generate.Generator, prependPath, path, appendPath string) {

diff --git a/internal/pkg/runtime/launcher/oci/process_linux_test.go b/internal/pkg/runtime/launcher/oci/process_linux_test.go
@@ -141,6 +141,8 @@ func TestGetProcessArgs(t *testing.T) {
 }
 
 func TestGetProcessEnvOCI(t *testing.T) {
+	defaultPathEnv := "PATH=" + env.DefaultPath
+
 	tests := []struct {
 		name     string
 		noCompat bool
@@ -155,7 +157,10 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			imageEnv: []string{},
 			hostEnv:  []string{},
 			userEnv:  map[string]string{},
-			wantEnv:  []string{"LD_LIBRARY_PATH=/.singularity.d/libs"},
+			wantEnv: []string{
+				defaultPathEnv,
+				"LD_LIBRARY_PATH=/.singularity.d/libs",
+			},
 		},
 		{
 			name:     "PassTERM",
@@ -165,6 +170,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			userEnv:  map[string]string{},
 			wantEnv: []string{
 				"TERM=xterm-256color",
+				defaultPathEnv,
 				"LD_LIBRARY_PATH=/.singularity.d/libs",
 			},
 		},
@@ -176,6 +182,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			userEnv:  map[string]string{},
 			wantEnv: []string{
 				"HTTP_PROXY=proxy.example.com:3128",
+				defaultPathEnv,
 				"LD_LIBRARY_PATH=/.singularity.d/libs",
 			},
 		},
@@ -185,7 +192,10 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			imageEnv: []string{},
 			hostEnv:  []string{"NOT_FOR_CONTAINER=true"},
 			userEnv:  map[string]string{},
-			wantEnv:  []string{"LD_LIBRARY_PATH=/.singularity.d/libs"},
+			wantEnv: []string{
+				defaultPathEnv,
+				"LD_LIBRARY_PATH=/.singularity.d/libs",
+			},
 		},
 		{
 			name:     "ImagePath",
@@ -239,6 +249,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			userEnv:  map[string]string{},
 			wantEnv: []string{
 				"LD_LIBRARY_PATH=/foo:/.singularity.d/libs",
+				defaultPathEnv,
 			},
 		},
 		{
@@ -248,6 +259,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			hostEnv:  []string{},
 			userEnv:  map[string]string{"LD_LIBRARY_PATH": "/foo"},
 			wantEnv: []string{
+				defaultPathEnv,
 				"LD_LIBRARY_PATH=/foo:/.singularity.d/libs",
 			},
 		},
@@ -259,6 +271,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			userEnv:  map[string]string{"LD_LIBRARY_PATH": "/bar"},
 			wantEnv: []string{
 				"LD_LIBRARY_PATH=/bar:/.singularity.d/libs",
+				defaultPathEnv,
 			},
 		},
 		{
@@ -269,6 +282,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			userEnv:  map[string]string{},
 			wantEnv: []string{
 				"FOO=bar",
+				defaultPathEnv,
 				"LD_LIBRARY_PATH=/.singularity.d/libs",
 			},
 		},
@@ -280,6 +294,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			userEnv:  map[string]string{"FOO": "baz"},
 			wantEnv: []string{
 				"FOO=baz",
+				defaultPathEnv,
 				"LD_LIBRARY_PATH=/.singularity.d/libs",
 			},
 		},
@@ -292,6 +307,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			wantEnv: []string{
 				"FOO=bar",
 				"ABC=123",
+				defaultPathEnv,
 				"LD_LIBRARY_PATH=/.singularity.d/libs",
 			},
 		},
@@ -303,6 +319,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			userEnv:  map[string]string{},
 			wantEnv: []string{
 				"FOO=bar",
+				defaultPathEnv,
 				"LD_LIBRARY_PATH=/.singularity.d/libs",
 			},
 		},
@@ -314,6 +331,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			userEnv:  map[string]string{},
 			wantEnv: []string{
 				"FOO=baz",
+				defaultPathEnv,
 				"LD_LIBRARY_PATH=/.singularity.d/libs",
 			},
 		},
@@ -325,6 +343,7 @@ func TestGetProcessEnvOCI(t *testing.T) {
 			userEnv:  map[string]string{"FOO": "baz"},
 			wantEnv: []string{
 				"FOO=baz",
+				defaultPathEnv,
 				"LD_LIBRARY_PATH=/.singularity.d/libs",
 			},
 		},