4 files changed, 30 insertions, 6 deletions
diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index a9da577348..1d598faa28 100644
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -49,6 +49,7 @@ libcommon_la_SOURCES = \
 if LINUX
 libcommon_la_SOURCES += \
 	lib/linux_version.c \
+	lib/shells.c \
 	lib/loopdev.c
 endif
 
diff --git a/lib/exec_shell.c b/lib/exec_shell.c
index ffe65f006e..8f10ea4df4 100644
--- a/lib/exec_shell.c
+++ b/lib/exec_shell.c
@@ -26,19 +26,15 @@
 #include "xalloc.h"
 
 #include "exec_shell.h"
-
-#define DEFAULT_SHELL "/bin/sh"
+#include "shells.h"
 
 void __attribute__((__noreturn__)) exec_shell(void)
 {
-	const char *shell = getenv("SHELL");
+	const char *shell = ul_default_shell(0, NULL);
 	char *shellc;
 	const char *shell_basename;
 	char *arg0;
 
-	if (!shell)
-		shell = DEFAULT_SHELL;
-
 	shellc = xstrdup(shell);
 	shell_basename = basename(shellc);
 	xasprintf(&arg0, "-%s", shell_basename);
diff --git a/lib/meson.build b/lib/meson.build
index 0f94a9b99b..cb35ecbd60 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -25,6 +25,7 @@ lib_common_sources = '''
 	randutils.c
 	sha1.c
 	sha256.c
+	shells.c
 	signames.c
 	strutils.c
 	strv.c
diff --git a/lib/shells.c b/lib/shells.c
index 13f293c5e0..ef2aecd0f5 100644
--- a/lib/shells.c
+++ b/lib/shells.c
@@ -1,6 +1,11 @@
 /*
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
+#include <sys/types.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <paths.h>
+#include <unistd.h>
 #include <sys/syslog.h>
 #if defined (HAVE_LIBECONF) && defined (USE_VENDORDIR)
 #include <libeconf.h>
@@ -116,3 +121,24 @@ extern int is_known_shell(const char *shell_name)
 #endif
 	return ret;
 }
+
+const char *ul_default_shell(int flags, const struct passwd *pw)
+{
+	const char *shell = NULL;
+
+	if (!(flags & UL_SHELL_NOENV)) {
+		shell = getenv("SHELL");
+		if (shell && *shell)
+			return shell;
+	}
+	if (!(flags & UL_SHELL_NOPWD)) {
+		if (!pw)
+			pw = getpwuid(getuid());
+		if (pw)
+			shell = pw->pw_shell;
+		if (shell && *shell)
+			return shell;
+	}
+
+	return _PATH_BSHELL;
+}