3 files changed, 86 insertions, 22 deletions

diff --git a/storage/filesystem/config.go b/storage/filesystem/config.go
index 01b35b4..dbdce54 100644
--- a/storage/filesystem/config.go
+++ b/storage/filesystem/config.go
@@ -5,6 +5,7 @@ import (
 	"os"
 
 	"github.com/go-git/go-git/v5/config"
+	format "github.com/go-git/go-git/v5/plumbing/format/config"
 	"github.com/go-git/go-git/v5/storage/filesystem/dotgit"
 	"github.com/go-git/go-git/v5/utils/ioutil"
 )
@@ -13,10 +14,11 @@ type ConfigStorage struct {
 	dir *dotgit.DotGit
 }
 
-func (c *ConfigStorage) Config() (conf *config.Config, err error) {
+func (c *ConfigStorage) Config() (*config.Config, error) {
 	cfg := config.NewConfig()
 
-	f, err := c.dir.Config()
+	// local config (./.git/config)
+	f, err := c.dir.LocalConfig()
 	if err != nil {
 		if os.IsNotExist(err) {
 			return cfg, nil
@@ -29,13 +31,55 @@ func (c *ConfigStorage) Config() (conf *config.Config, err error) {
 
 	b, err := stdioutil.ReadAll(f)
 	if err != nil {
+		return cfg, err
+	}
+
+	if err = cfg.UnmarshalScoped(format.LocalScope, b); err != nil {
+		return cfg, err
+	}
+
+	// global config (~/.gitconfig)
+	f, err = c.dir.GlobalConfig()
+	if err != nil {
+		if os.IsNotExist(err) {
+			return cfg, nil
+		}
+
 		return nil, err
 	}
 
-	if err = cfg.Unmarshal(b); err != nil {
+	defer ioutil.CheckClose(f, &err)
+
+	b, err = stdioutil.ReadAll(f)
+	if err != nil {
+		return cfg, err
+	}
+
+	if err = cfg.UnmarshalScoped(format.GlobalScope, b); err != nil {
+		return cfg, err
+	}
+
+	// system config (/etc/gitconfig)
+	f, err = c.dir.SystemConfig()
+	if err != nil {
+		if os.IsNotExist(err) {
+			return cfg, nil
+		}
+
 		return nil, err
 	}
 
+	defer ioutil.CheckClose(f, &err)
+
+	b, err = stdioutil.ReadAll(f)
+	if err != nil {
+		return cfg, err
+	}
+
+	if err = cfg.UnmarshalScoped(format.SystemScope, b); err != nil {
+		return cfg, err
+	}
+
 	return cfg, err
 }
 
@@ -44,7 +88,7 @@ func (c *ConfigStorage) SetConfig(cfg *config.Config) (err error) {
 		return err
 	}
 
-	f, err := c.dir.ConfigWriter()
+	f, err := c.dir.LocalConfigWriter()
 	if err != nil {
 		return err
 	}
diff --git a/storage/filesystem/dotgit/dotgit.go b/storage/filesystem/dotgit/dotgit.go
index 3ce9dae..503ce18 100644
--- a/storage/filesystem/dotgit/dotgit.go
+++ b/storage/filesystem/dotgit/dotgit.go
@@ -21,15 +21,17 @@ import (
 )
 
 const (
-	suffix         = ".git"
-	packedRefsPath = "packed-refs"
-	configPath     = "config"
-	indexPath      = "index"
-	shallowPath    = "shallow"
-	modulePath     = "modules"
-	objectsPath    = "objects"
-	packPath       = "pack"
-	refsPath       = "refs"
+	suffix           = ".git"
+	packedRefsPath   = "packed-refs"
+	localConfigPath  = "config"
+	globalConfigPath = ".gitconfig"
+	systemConfigPath = "/etc/gitconfig"
+	indexPath        = "index"
+	shallowPath      = "shallow"
+	modulePath       = "modules"
+	objectsPath      = "objects"
+	packPath         = "pack"
+	refsPath         = "refs"
 
 	tmpPackedRefsPrefix = "._packed-refs"
 
@@ -152,14 +154,32 @@ func (d *DotGit) Close() error {
 	return nil
 }
 
-// ConfigWriter returns a file pointer for write to the config file
-func (d *DotGit) ConfigWriter() (billy.File, error) {
-	return d.fs.Create(configPath)
+// LocalConfigWriter returns a file pointer for write to the local config file
+func (d *DotGit) LocalConfigWriter() (billy.File, error) {
+	return d.fs.Create(localConfigPath)
 }
 
-// Config returns a file pointer for read to the config file
-func (d *DotGit) Config() (billy.File, error) {
-	return d.fs.Open(configPath)
+// LocalConfig returns a file pointer for read to the local config file
+func (d *DotGit) LocalConfig() (billy.File, error) {
+	return d.fs.Open(localConfigPath)
+}
+
+// GlobalConfigWriter returns a file pointer for write to the global config file
+func (d *DotGit) GlobalConfigWriter() (billy.File, error) {
+	return osfs.New(os.Getenv("HOME")).Create(globalConfigPath)
+}
+
+// GlobalConfig returns a file pointer for read to the global config file
+func (d *DotGit) GlobalConfig() (billy.File, error) {
+	return osfs.New(os.Getenv("HOME")).Open(globalConfigPath)
+}
+
+// SystemConfigWriter doesn't exist because we typically do not have permission
+// to write to files in /etc.
+
+// SystemConfig returns a file pointer for read to the system config file
+func (d *DotGit) SystemConfig() (billy.File, error) {
+	return osfs.New("/").Open(systemConfigPath)
 }
 
 // IndexWriter returns a file pointer for write to the index file
diff --git a/storage/filesystem/dotgit/dotgit_test.go b/storage/filesystem/dotgit/dotgit_test.go
index cf81c23..d57ff15 100644
--- a/storage/filesystem/dotgit/dotgit_test.go
+++ b/storage/filesystem/dotgit/dotgit_test.go
@@ -332,7 +332,7 @@ func (s *SuiteDotGit) TestConfig(c *C) {
 	fs := fixtures.Basic().ByTag(".git").One().DotGit()
 	dir := New(fs)
 
-	file, err := dir.Config()
+	file, err := dir.LocalConfig()
 	c.Assert(err, IsNil)
 	c.Assert(filepath.Base(file.Name()), Equals, "config")
 }
@@ -345,13 +345,13 @@ func (s *SuiteDotGit) TestConfigWriteAndConfig(c *C) {
 	fs := osfs.New(tmp)
 	dir := New(fs)
 
-	f, err := dir.ConfigWriter()
+	f, err := dir.LocalConfigWriter()
 	c.Assert(err, IsNil)
 
 	_, err = f.Write([]byte("foo"))
 	c.Assert(err, IsNil)
 
-	f, err = dir.Config()
+	f, err = dir.LocalConfig()
 	c.Assert(err, IsNil)
 
 	cnt, err := ioutil.ReadAll(f)