interfaces/mount: add function for parsing fstab-like file

interfaces/mount/entry.go

@@ -20,7 +20,9 @@
 package mount
 
 import (
+	"bufio"
 	"fmt"
+	"io"
 	"strconv"
 	"strings"
 )
@@ -141,3 +143,30 @@ func ParseEntry(s string) (Entry, error) {
 	e.CheckPassNumber = cpn
 	return e, nil
 }
+
+// LoadFSTab reads and parses an fstab-like file.
+//
+// The supported format is described by fstab(5).
+func LoadFSTab(reader io.Reader) ([]Entry, error) {
+	var entries []Entry
+	scanner := bufio.NewScanner(reader)
+	for scanner.Scan() {
+		s := scanner.Text()
+		if i := strings.IndexByte(s, '#'); i != -1 {
+			s = s[0:i]
+		}
+		s = strings.TrimSpace(s)
+		if s == "" {
+			continue
+		}
+		entry, err := ParseEntry(s)
+		if err != nil {
+			return nil, err
+		}
+		entries = append(entries, entry)
+	}
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+	return entries, nil
+}

interfaces/mount/entry_test.go

@@ -20,6 +20,8 @@
 package mount_test
 
 import (
+	"strings"
+
 	. "gopkg.in/check.v1"
 
 	"github.com/snapcore/snapd/interfaces/mount"
@@ -148,3 +150,30 @@ func (s *entrySuite) TestParseEntry6(c *C) {
 	c.Assert(e.DumpFrequency, Equals, 5)
 	c.Assert(e.CheckPassNumber, Equals, 7)
 }
+
+// Test that empty fstab is parsed without errors
+func (s *entrySuite) TestLoadFSTab1(c *C) {
+	entries, err := mount.LoadFSTab(strings.NewReader(""))
+	c.Assert(err, IsNil)
+	c.Assert(entries, HasLen, 0)
+}
+
+// Test that '#'-comments are skipped
+func (s *entrySuite) TestLoadFSTab2(c *C) {
+	entries, err := mount.LoadFSTab(strings.NewReader("# comment"))
+	c.Assert(err, IsNil)
+	c.Assert(entries, HasLen, 0)
+}
+
+// Test that simple profile can be loaded correctly.
+func (s *entrySuite) TestLoadFSTab3(c *C) {
+	entries, err := mount.LoadFSTab(strings.NewReader(`
+	name-1 dir-1 type-1 options-1 1 1 # 1st entry
+	name-2 dir-2 type-2 options-2 2 2 # 2nd entry`))
+	c.Assert(err, IsNil)
+	c.Assert(entries, HasLen, 2)
+	c.Assert(entries, DeepEquals, []mount.Entry{
+		{"name-1", "dir-1", "type-1", []string{"options-1"}, 1, 1},
+		{"name-2", "dir-2", "type-2", []string{"options-2"}, 2, 2},
+	})
+}