changes to allow for darwin compilation

Signed-off-by: baude <bbaude@redhat.com>

Closes: #1015
Approved by: baude

3 files changed, 136 insertions, 103 deletions

diff --git a/pkg/rootless/rootless.go b/pkg/rootless/rootless.go
index 737fc91c7..ca851f9bc 100644
--- a/pkg/rootless/rootless.go
+++ b/pkg/rootless/rootless.go
@@ -2,16 +2,9 @@ package rootless
 
 import (
 	"fmt"
-	"io/ioutil"
+	"github.com/containers/storage/pkg/idtools"
 	"os"
 	"os/exec"
-	gosignal "os/signal"
-	"runtime"
-	"syscall"
-
-	"github.com/containers/storage/pkg/idtools"
-	"github.com/docker/docker/pkg/signal"
-	"github.com/pkg/errors"
 )
 
 /*
@@ -25,11 +18,6 @@ func runInUser() error {
 	return nil
 }
 
-// IsRootless tells us if we are running in rootless mode
-func IsRootless() bool {
-	return os.Getuid() != 0 || os.Getenv("_LIBPOD_USERNS_CONFIGURED") != ""
-}
-
 func tryMappingTool(tool string, pid int, hostID int, mappings []idtools.IDMap) error {
 	path, err := exec.LookPath(tool)
 	if err != nil {
@@ -53,93 +41,3 @@ func tryMappingTool(tool string, pid int, hostID int, mappings []idtools.IDMap)
 	}
 	return cmd.Run()
 }
-
-// BecomeRootInUserNS re-exec podman in a new userNS
-func BecomeRootInUserNS() (bool, error) {
-
-	if os.Getuid() == 0 || os.Getenv("_LIBPOD_USERNS_CONFIGURED") != "" {
-		if os.Getenv("_LIBPOD_USERNS_CONFIGURED") == "init" {
-			return false, runInUser()
-		}
-		return false, nil
-	}
-
-	runtime.LockOSThread()
-	defer runtime.UnlockOSThread()
-
-	r, w, err := os.Pipe()
-	if err != nil {
-		return false, err
-	}
-	defer r.Close()
-	defer w.Close()
-
-	pidC := C.reexec_in_user_namespace(C.int(r.Fd()))
-	pid := int(pidC)
-	if pid < 0 {
-		return false, errors.Errorf("cannot re-exec process")
-	}
-
-	setgroups := fmt.Sprintf("/proc/%d/setgroups", pid)
-	err = ioutil.WriteFile(setgroups, []byte("deny\n"), 0666)
-	if err != nil {
-		return false, errors.Wrapf(err, "cannot write setgroups file")
-	}
-
-	var uids, gids []idtools.IDMap
-	username := os.Getenv("USER")
-	mappings, err := idtools.NewIDMappings(username, username)
-	if err == nil {
-		uids = mappings.UIDs()
-		gids = mappings.GIDs()
-	}
-
-	uidsMapped := false
-	if mappings != nil && uids != nil {
-		uidsMapped = tryMappingTool("newuidmap", pid, os.Getuid(), uids) == nil
-	}
-	if !uidsMapped {
-		uidMap := fmt.Sprintf("/proc/%d/uid_map", pid)
-		err = ioutil.WriteFile(uidMap, []byte(fmt.Sprintf("%d %d 1\n", 0, os.Getuid())), 0666)
-		if err != nil {
-			return false, errors.Wrapf(err, "cannot write uid_map")
-		}
-	}
-
-	gidsMapped := false
-	if mappings != nil && gids != nil {
-		gidsMapped = tryMappingTool("newgidmap", pid, os.Getgid(), gids) == nil
-	}
-	if !gidsMapped {
-		gidMap := fmt.Sprintf("/proc/%d/gid_map", pid)
-		err = ioutil.WriteFile(gidMap, []byte(fmt.Sprintf("%d %d 1\n", 0, os.Getgid())), 0666)
-		if err != nil {
-			return false, errors.Wrapf(err, "cannot write gid_map")
-		}
-	}
-
-	_, err = w.Write([]byte("1"))
-	if err != nil {
-		return false, errors.Wrapf(err, "write to sync pipe")
-	}
-
-	c := make(chan os.Signal, 1)
-
-	gosignal.Notify(c)
-	defer gosignal.Reset()
-	go func() {
-		for s := range c {
-			if s == signal.SIGCHLD || s == signal.SIGPIPE {
-				continue
-			}
-
-			syscall.Kill(int(pidC), s.(syscall.Signal))
-		}
-	}()
-
-	if C.reexec_in_user_namespace_wait(pidC) < 0 {
-		return false, errors.Wrapf(err, "error waiting for the re-exec process")
-	}
-
-	return true, nil
-}
diff --git a/pkg/rootless/rootless_linux.go b/pkg/rootless/rootless_linux.go
new file mode 100644
index 000000000..5b4094bf2
--- /dev/null
+++ b/pkg/rootless/rootless_linux.go
@@ -0,0 +1,117 @@
+// build +linux
+
+package rootless
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	gosignal "os/signal"
+	"runtime"
+	"syscall"
+
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/docker/docker/pkg/signal"
+	"github.com/pkg/errors"
+)
+
+/*
+extern int reexec_in_user_namespace(int ready);
+extern int reexec_in_user_namespace_wait(int pid);
+*/
+import "C"
+
+// IsRootless tells us if we are running in rootless mode
+func IsRootless() bool {
+	return os.Getuid() != 0 || os.Getenv("_LIBPOD_USERNS_CONFIGURED") != ""
+}
+
+// BecomeRootInUserNS re-exec podman in a new userNS
+func BecomeRootInUserNS() (bool, error) {
+
+	if os.Getuid() == 0 || os.Getenv("_LIBPOD_USERNS_CONFIGURED") != "" {
+		if os.Getenv("_LIBPOD_USERNS_CONFIGURED") == "init" {
+			return false, runInUser()
+		}
+		return false, nil
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	r, w, err := os.Pipe()
+	if err != nil {
+		return false, err
+	}
+	defer r.Close()
+	defer w.Close()
+
+	pidC := C.reexec_in_user_namespace(C.int(r.Fd()))
+	pid := int(pidC)
+	if pid < 0 {
+		return false, errors.Errorf("cannot re-exec process")
+	}
+
+	setgroups := fmt.Sprintf("/proc/%d/setgroups", pid)
+	err = ioutil.WriteFile(setgroups, []byte("deny\n"), 0666)
+	if err != nil {
+		return false, errors.Wrapf(err, "cannot write setgroups file")
+	}
+
+	var uids, gids []idtools.IDMap
+	username := os.Getenv("USER")
+	mappings, err := idtools.NewIDMappings(username, username)
+	if err == nil {
+		uids = mappings.UIDs()
+		gids = mappings.GIDs()
+	}
+
+	uidsMapped := false
+	if mappings != nil && uids != nil {
+		uidsMapped = tryMappingTool("newuidmap", pid, os.Getuid(), uids) == nil
+	}
+	if !uidsMapped {
+		uidMap := fmt.Sprintf("/proc/%d/uid_map", pid)
+		err = ioutil.WriteFile(uidMap, []byte(fmt.Sprintf("%d %d 1\n", 0, os.Getuid())), 0666)
+		if err != nil {
+			return false, errors.Wrapf(err, "cannot write uid_map")
+		}
+	}
+
+	gidsMapped := false
+	if mappings != nil && gids != nil {
+		gidsMapped = tryMappingTool("newgidmap", pid, os.Getgid(), gids) == nil
+	}
+	if !gidsMapped {
+		gidMap := fmt.Sprintf("/proc/%d/gid_map", pid)
+		err = ioutil.WriteFile(gidMap, []byte(fmt.Sprintf("%d %d 1\n", 0, os.Getgid())), 0666)
+		if err != nil {
+			return false, errors.Wrapf(err, "cannot write gid_map")
+		}
+	}
+
+	_, err = w.Write([]byte("1"))
+	if err != nil {
+		return false, errors.Wrapf(err, "write to sync pipe")
+	}
+
+	c := make(chan os.Signal, 1)
+
+	gosignal.Notify(c)
+	defer gosignal.Reset()
+	go func() {
+		for s := range c {
+			if s == signal.SIGCHLD || s == signal.SIGPIPE {
+				continue
+			}
+
+			syscall.Kill(int(pidC), s.(syscall.Signal))
+		}
+	}()
+
+	if C.reexec_in_user_namespace_wait(pidC) < 0 {
+		return false, errors.Wrapf(err, "error waiting for the re-exec process")
+	}
+
+	return true, nil
+}
diff --git a/pkg/rootless/rootless_unsupported.go b/pkg/rootless/rootless_unsupported.go
new file mode 100644
index 000000000..e4067a764
--- /dev/null
+++ b/pkg/rootless/rootless_unsupported.go
@@ -0,0 +1,18 @@
+// +build !linux
+
+package rootless
+
+import (
+	"github.com/pkg/errors"
+)
+
+// IsRootless returns false on all non-linux platforms
+func IsRootless() bool {
+	return false
+}
+
+// BecomeRootInUserNS is a stub function that always returns false and an
+// error on unsupported OS's
+func BecomeRootInUserNS() (bool, error) {
+	return false, errors.New("this function is not supported on this os")
+}