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Merge pull request #2392 from mvo5/feature/native-grubenv
partition: add support for native grubenv read/write and use it
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,123 @@ | ||
| // -*- Mode: Go; indent-tabs-mode: t -*- | ||
|
|
||
| /* | ||
| * Copyright (C) 2014-2015 Canonical Ltd | ||
| * | ||
| * This program is free software: you can redistribute it and/or modify | ||
| * it under the terms of the GNU General Public License version 3 as | ||
| * published by the Free Software Foundation. | ||
| * | ||
| * This program is distributed in the hope that it will be useful, | ||
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
| * GNU General Public License for more details. | ||
| * | ||
| * You should have received a copy of the GNU General Public License | ||
| * along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
| * | ||
| */ | ||
|
|
||
| package grubenv | ||
|
|
||
| import ( | ||
| "bytes" | ||
| "fmt" | ||
| "io/ioutil" | ||
| "os" | ||
| ) | ||
|
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| // FIXME: support for escaping (embedded \n in grubenv) missing | ||
| type Env struct { | ||
| env map[string]string | ||
| ordering []string | ||
|
|
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| path string | ||
| } | ||
|
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| func NewEnv(path string) *Env { | ||
| return &Env{ | ||
| env: make(map[string]string), | ||
| path: path, | ||
| } | ||
| } | ||
|
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| func (g *Env) Get(name string) string { | ||
| return g.env[name] | ||
| } | ||
|
|
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| func (g *Env) Set(key, value string) { | ||
| var contains = func(needle string, haystack []string) bool { | ||
| for _, k := range haystack { | ||
| if k == key { | ||
| return true | ||
| } | ||
| } | ||
| return false | ||
| } | ||
| if !contains(key, g.ordering) { | ||
| g.ordering = append(g.ordering, key) | ||
| } | ||
|
|
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| g.env[key] = value | ||
| } | ||
|
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| func (g *Env) Load() error { | ||
| buf, err := ioutil.ReadFile(g.path) | ||
| if err != nil { | ||
| return err | ||
| } | ||
| if len(buf) != 1024 { | ||
| return fmt.Errorf("grubenv %q must be exactly 1024 byte, got %d", g.path, len(buf)) | ||
| } | ||
| if !bytes.HasPrefix(buf, []byte("# GRUB Environment Block\n")) { | ||
| return fmt.Errorf("cannot find grubenv header in %q", g.path) | ||
| } | ||
| rawEnv := bytes.Split(buf, []byte("\n")) | ||
| for _, env := range rawEnv[1:] { | ||
| l := bytes.SplitN(env, []byte("="), 2) | ||
| // be liberal in what you accept | ||
| if len(l) < 2 { | ||
| continue | ||
| } | ||
| k := string(l[0]) | ||
| v := string(l[1]) | ||
| g.env[k] = v | ||
| g.ordering = append(g.ordering, k) | ||
| } | ||
|
|
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| return nil | ||
| } | ||
|
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| func (g *Env) Save() error { | ||
| w := bytes.NewBuffer(nil) | ||
| w.Grow(1024) | ||
|
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| fmt.Fprintf(w, "# GRUB Environment Block\n") | ||
| for _, k := range g.ordering { | ||
| if _, err := fmt.Fprintf(w, "%s=%s\n", k, g.env[k]); err != nil { | ||
| return err | ||
| } | ||
| } | ||
| if w.Len() > 1024 { | ||
| return fmt.Errorf("cannot write grubenv %q: bigger than 1024 bytes (%d)", g.path, w.Len()) | ||
| } | ||
| content := w.Bytes()[:w.Cap()] | ||
| for i := w.Len(); i < len(content); i++ { | ||
| content[i] = '#' | ||
| } | ||
|
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| // write in place to avoid the file moving on disk | ||
| // (thats what grubenv is also doing) | ||
| f, err := os.Create(g.path) | ||
| if err != nil { | ||
| return err | ||
| } | ||
| if _, err := f.Write(content); err != nil { | ||
| return err | ||
| } | ||
| if err := f.Sync(); err != nil { | ||
| return err | ||
| } | ||
|
|
||
| return f.Close() | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,94 @@ | ||
| // -*- Mode: Go; indent-tabs-mode: t -*- | ||
|
|
||
| /* | ||
| * Copyright (C) 2014-2015 Canonical Ltd | ||
| * | ||
| * This program is free software: you can redistribute it and/or modify | ||
| * it under the terms of the GNU General Public License version 3 as | ||
| * published by the Free Software Foundation. | ||
| * | ||
| * This program is distributed in the hope that it will be useful, | ||
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
| * GNU General Public License for more details. | ||
| * | ||
| * You should have received a copy of the GNU General Public License | ||
| * along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
| * | ||
| */ | ||
|
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| package grubenv_test | ||
|
|
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| import ( | ||
| "fmt" | ||
| "io/ioutil" | ||
| "path/filepath" | ||
| "testing" | ||
|
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| . "gopkg.in/check.v1" | ||
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| "github.com/snapcore/snapd/partition/grubenv" | ||
| ) | ||
|
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| // Hook up check.v1 into the "go test" runner | ||
| func Test(t *testing.T) { TestingT(t) } | ||
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| type grubenvTestSuite struct { | ||
| envPath string | ||
| } | ||
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| var _ = Suite(&grubenvTestSuite{}) | ||
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| func (g *grubenvTestSuite) SetUpTest(c *C) { | ||
| g.envPath = filepath.Join(c.MkDir(), "grubenv") | ||
| } | ||
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| func (g *grubenvTestSuite) TestSet(c *C) { | ||
| env := grubenv.NewEnv(g.envPath) | ||
| c.Check(env, NotNil) | ||
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| env.Set("key", "value") | ||
| c.Check(env.Get("key"), Equals, "value") | ||
| } | ||
|
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| func (g *grubenvTestSuite) TestSave(c *C) { | ||
| env := grubenv.NewEnv(g.envPath) | ||
| c.Check(env, NotNil) | ||
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| env.Set("key1", "value1") | ||
| env.Set("key2", "value2") | ||
| env.Set("key3", "value3") | ||
| env.Set("key4", "value4") | ||
| env.Set("key5", "value5") | ||
| env.Set("key6", "value6") | ||
| env.Set("key7", "value7") | ||
| // set "key1" again, ordering (position) does not change | ||
| env.Set("key1", "value1") | ||
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| err := env.Save() | ||
| c.Assert(err, IsNil) | ||
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| buf, err := ioutil.ReadFile(g.envPath) | ||
| c.Assert(err, IsNil) | ||
| c.Assert(buf, DeepEquals, []byte(`# GRUB Environment Block | ||
| key1=value1 | ||
| key2=value2 | ||
| key3=value3 | ||
| key4=value4 | ||
| key5=value5 | ||
| key6=value6 | ||
| key7=value7 | ||
| ###################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################################`)) | ||
| } | ||
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| func (g *grubenvTestSuite) TestSaveOverflow(c *C) { | ||
| env := grubenv.NewEnv(g.envPath) | ||
| c.Check(env, NotNil) | ||
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| for i := 0; i < 101; i++ { | ||
| env.Set(fmt.Sprintf("key%d", i), "foo") | ||
| } | ||
|
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| err := env.Save() | ||
| c.Assert(err, ErrorMatches, `cannot write grubenv .*: bigger than 1024 bytes \(1026\)`) | ||
| } |