system/acl: wrap libacl errors in PathError

This helps determine which libacl function the errno came from.

Signed-off-by: Ophestra <cat@gensokyo.uk>

system/acl/acl.go

@@ -29,8 +29,5 @@ func Update(name string, uid int, perms ...Perm) error {
 		(*C.acl_perm_t)(p),
 		C.size_t(len(perms)),
 	)
-	if r == 0 {
+	return newAclPathError(name, int(r), err)
-		return nil
-	}
-	return err
 }

system/acl/libacl-helper.c

@@ -6,7 +6,7 @@
 
 int hakurei_acl_update_file_by_uid(const char *path_p, uid_t uid,
                                    acl_perm_t *perms, size_t plen) {
-  int ret = -1;
+  int ret;
   bool v;
   int i;
   acl_t acl;
@@ -15,51 +15,70 @@ int hakurei_acl_update_file_by_uid(const char *path_p, uid_t uid,
   void *qualifier_p;
   acl_permset_t permset;
 
+  ret = -1; /* acl_get_file */
   acl = acl_get_file(path_p, ACL_TYPE_ACCESS);
   if (acl == NULL)
     goto out;
 
-  // prune entries by uid
+  /* prune entries by uid */
   for (i = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry); i == 1;
        i = acl_get_entry(acl, ACL_NEXT_ENTRY, &entry)) {
+    ret = -2; /* acl_get_tag_type */
     if (acl_get_tag_type(entry, &tag_type) != 0)
-      return -1;
+      goto out;
     if (tag_type != ACL_USER)
       continue;
 
+    ret = -3; /* acl_get_qualifier */
     qualifier_p = acl_get_qualifier(entry);
     if (qualifier_p == NULL)
-      return -1;
+      goto out;
     v = *(uid_t *)qualifier_p == uid;
     acl_free(qualifier_p);
 
     if (!v)
       continue;
 
-    acl_delete_entry(acl, entry);
+    ret = -4; /* acl_delete_entry */
+    if (acl_delete_entry(acl, entry) != 0)
+      goto out;
   }
 
   if (plen == 0)
     goto set;
 
+  ret = -5; /* acl_create_entry */
   if (acl_create_entry(&acl, &entry) != 0)
     goto out;
+
+  ret = -6; /* acl_get_permset */
   if (acl_get_permset(entry, &permset) != 0)
     goto out;
+
+  ret = -7; /* acl_add_perm */
   for (i = 0; i < plen; i++) {
     if (acl_add_perm(permset, perms[i]) != 0)
       goto out;
   }
+
+  ret = -8; /* acl_set_tag_type */
   if (acl_set_tag_type(entry, ACL_USER) != 0)
     goto out;
+
+  ret = -9; /* acl_set_qualifier */
   if (acl_set_qualifier(entry, (void *)&uid) != 0)
     goto out;
 
 set:
+  ret = -10; /* acl_calc_mask */
   if (acl_calc_mask(&acl) != 0)
     goto out;
+
+  ret = -11; /* acl_valid */
   if (acl_valid(acl) != 0)
     goto out;
+
+  ret = -12; /* acl_set_file */
   if (acl_set_file(path_p, ACL_TYPE_ACCESS, acl) == 0)
     ret = 0;
 

system/acl/libacl-helper.go

@@ -0,0 +1,40 @@
+package acl
+
+import "os"
+
+func newAclPathError(name string, r int, err error) error {
+	pathError := &os.PathError{Path: name, Err: err}
+	switch r {
+	case 0:
+		return nil
+
+	case -1:
+		pathError.Op = "acl_get_file"
+	case -2:
+		pathError.Op = "acl_get_tag_type"
+	case -3:
+		pathError.Op = "acl_get_qualifier"
+	case -4:
+		pathError.Op = "acl_delete_entry"
+	case -5:
+		pathError.Op = "acl_create_entry"
+	case -6:
+		pathError.Op = "acl_get_permset"
+	case -7:
+		pathError.Op = "acl_add_perm"
+	case -8:
+		pathError.Op = "acl_set_tag_type"
+	case -9:
+		pathError.Op = "acl_set_qualifier"
+	case -10:
+		pathError.Op = "acl_calc_mask"
+	case -11:
+		pathError.Op = "acl_valid"
+	case -12:
+		pathError.Op = "acl_set_file"
+
+	default: // unreachable
+		pathError.Op = "setfacl"
+	}
+	return pathError
+}

system/acl/libacl-helper_test.go

@@ -0,0 +1,60 @@
+package acl
+
+import (
+	"os"
+	"reflect"
+	"syscall"
+	"testing"
+
+	"hakurei.app/container"
+)
+
+func TestNewAclPathError(t *testing.T) {
+	testCases := []struct {
+		name string
+		path string
+		r    int
+		err  error
+		want error
+	}{
+		{"nil", container.Nonexistent, 0, syscall.ENOTRECOVERABLE, nil},
+
+		{"acl_get_file", container.Nonexistent, -1, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_get_file", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_get_tag_type", container.Nonexistent, -2, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_get_tag_type", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_get_qualifier", container.Nonexistent, -3, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_get_qualifier", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_delete_entry", container.Nonexistent, -4, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_delete_entry", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_create_entry", container.Nonexistent, -5, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_create_entry", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_get_permset", container.Nonexistent, -6, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_get_permset", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_add_perm", container.Nonexistent, -7, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_add_perm", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_set_tag_type", container.Nonexistent, -8, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_set_tag_type", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_set_qualifier", container.Nonexistent, -9, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_set_qualifier", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_calc_mask", container.Nonexistent, -10, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_calc_mask", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_valid", container.Nonexistent, -11, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_valid", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"acl_set_file", container.Nonexistent, -12, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "acl_set_file", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+
+		{"acl", container.Nonexistent, -13, syscall.ENOTRECOVERABLE,
+			&os.PathError{Op: "setfacl", Path: container.Nonexistent, Err: syscall.ENOTRECOVERABLE}},
+		{"invalid", container.Nonexistent, -0xdeadbeef, nil,
+			&os.PathError{Op: "setfacl", Path: container.Nonexistent}},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			err := newAclPathError(tc.path, tc.r, tc.err)
+			if !reflect.DeepEqual(err, tc.want) {
+				t.Errorf("newAclPathError: %v, want %v", err, tc.want)
+			}
+		})
+	}
+}