From c46bc7e2162d774f55847c1a8cb9d49085cf89bb Mon Sep 17 00:00:00 2001
From: Shawn Landden <slandden@gmail.com>
Date: Mon, 15 Jan 2018 10:17:51 -0800
Subject: [PATCH] machined: use getent to get default shell for machinectl
 shell (#7684)

Closes: https://github.com/systemd/systemd/issues/1395
---
 man/machinectl.xml         |  5 +++--
 src/machine/machine-dbus.c | 41 ++++++++++++++++++++++++++++----------
 2 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/man/machinectl.xml b/man/machinectl.xml
index b381b9a1cd4..94f2ba511c2 100644
--- a/man/machinectl.xml
+++ b/man/machinectl.xml
@@ -440,8 +440,9 @@
         instead. This works similar to <command>login</command> but
         immediately invokes a user process. This command runs the
         specified executable with the specified arguments, or
-        <filename>/bin/sh</filename> if none is specified. By default,
-        opens a <literal>root</literal> shell, but by using
+        specified executable with the specified arguments, or the
+        default shell for the user if none is specified, or
+        <filename>/bin/sh</filename> if no default shell is found. By default,
         <option>--uid=</option>, or by prefixing the machine name with
         a username and an <literal>@</literal> character, a different
         user may be selected. Use <option>--setenv=</option> to set
diff --git a/src/machine/machine-dbus.c b/src/machine/machine-dbus.c
index 0ca2e54ed9d..2d7806491bf 100644
--- a/src/machine/machine-dbus.c
+++ b/src/machine/machine-dbus.c
@@ -609,7 +609,7 @@ int bus_machine_method_open_shell(sd_bus_message *message, void *userdata, sd_bu
         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *allocated_bus = NULL;
         sd_bus *container_bus = NULL;
         _cleanup_close_ int master = -1, slave = -1;
-        _cleanup_strv_free_ char **env = NULL, **args = NULL;
+        _cleanup_strv_free_ char **env = NULL, **args_wire = NULL, **args = NULL;
         Machine *m = userdata;
         const char *p, *unit, *user, *path, *description, *utmp_id;
         int r;
@@ -621,22 +621,41 @@ int bus_machine_method_open_shell(sd_bus_message *message, void *userdata, sd_bu
         if (r < 0)
                 return r;
         user = empty_to_null(user);
-        if (isempty(path))
-                path = "/bin/sh";
-        if (!path_is_absolute(path))
-                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Specified path '%s' is not absolute", path);
-
-        r = sd_bus_message_read_strv(message, &args);
+        r = sd_bus_message_read_strv(message, &args_wire);
         if (r < 0)
                 return r;
-        if (strv_isempty(args)) {
-                args = strv_free(args);
+        if (isempty(path)) {
+                path = "/bin/sh";
 
-                args = strv_new(path, NULL);
+                args = new0(char*, 3 + 1);
                 if (!args)
                         return -ENOMEM;
+                args[0] = strdup("sh");
+                if (!args[0])
+                        return -ENOMEM;
+                args[1] = strdup("-c");
+                if (!args[1])
+                        return -ENOMEM;
+                r = asprintf(&args[2],
+                             "shell=$(getent passwd %s 2>/dev/null | { IFS=: read _ _ _ _ _ _ x; echo \"$x\"; })\n"\
+                             "exec \"${shell:-/bin/sh}\" -l", /* -l is means --login */
+                             isempty(user) ? "root" : user);
+                if (r < 0) {
+                        args[2] = NULL;
+                        return -ENOMEM;
+                }
+        } else {
+                if (!path_is_absolute(path))
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Specified path '%s' is not absolute", path);
+                args = args_wire;
+                args_wire = NULL;
+                if (strv_isempty(args)) {
+                        args = strv_free(args);
 
-                args[0][0] = '-'; /* Tell /bin/sh that this shall be a login shell */
+                        args = strv_new(path, NULL);
+                        if (!args)
+                                return -ENOMEM;
+                }
         }
 
         r = sd_bus_message_read_strv(message, &env);