[PATCH 3/3] login-utils, sys-utils: use _PATH_BSHELL consistently

Remove local DEFAULT_SHELL definitions and hardcoded "/bin/sh" strings
in favor of the standard _PATH_BSHELL macro from <paths.h>. This
provides consistency across the codebase while following libc
conventions.

These tools already perform their own passwd lookups and only need a
fallback value, so they don't require the full ul_default_shell()
resolution logic.

Affected tools:
- su(1): already checks pw_shell validity
- sulogin(8): emergency login with explicit shell handling
- setpriv(1): already has passwd entry for environment setup

Signed-off-by: Alessandro Ratti <[email protected]>
---
 login-utils/su-common.c | 5 +----
 login-utils/sulogin.c   | 9 +++++----
 sys-utils/setpriv.c     | 6 ++----
 3 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/login-utils/su-common.c b/login-utils/su-common.c
index 4d54eab31..c6232ce7a 100644
--- a/login-utils/su-common.c
+++ b/login-utils/su-common.c
@@ -105,9 +105,6 @@ UL_DEBUG_DEFINE_MASKNAMES(su) = UL_DEBUG_EMPTY_MASKNAMES;
 
 #define is_pam_failure(_rc)	((_rc) != PAM_SUCCESS)
 
-/* The shell to run if none is given in the user's passwd entry.  */
-#define DEFAULT_SHELL "/bin/sh"
-
 /* The user to become if none is specified.  */
 #define DEFAULT_USER "root"
 
@@ -1167,7 +1164,7 @@ int su_main(int argc, char **argv, int mode)
 	su->old_user = xgetlogin();
 
 	if (!su->pwd->pw_shell || !*su->pwd->pw_shell)
-		su->pwd->pw_shell = DEFAULT_SHELL;
+		su->pwd->pw_shell = _PATH_BSHELL;
 
 	if (use_supp && !use_gid)
 		su->pwd->pw_gid = groups[0];
diff --git a/login-utils/sulogin.c b/login-utils/sulogin.c
index eb4609db6..c546cc7c1 100644
--- a/login-utils/sulogin.c
+++ b/login-utils/sulogin.c
@@ -34,6 +34,7 @@
 #include <fcntl.h>
 #include <signal.h>
 #include <pwd.h>
+#include <paths.h>
 #include <shadow.h>
 #include <termios.h>
 #include <errno.h>
@@ -892,7 +893,7 @@ static void sushell(struct passwd *pwd, struct console *con)
 		if (pwd->pw_shell[0])
 			su_shell = pwd->pw_shell;
 		else
-			su_shell = "/bin/sh";
+			su_shell = _PATH_BSHELL;
 	}
 	if ((p = strrchr(su_shell, '/')) == NULL)
 		p = su_shell;
@@ -941,9 +942,9 @@ static void sushell(struct passwd *pwd, struct console *con)
 	execl(su_shell, shell, (char *)NULL);
 	warn(_("failed to execute %s"), su_shell);
 
-	xsetenv("SHELL", "/bin/sh", 1);
-	execl("/bin/sh", profile ? "-sh" : "sh", (char *)NULL);
-	warn(_("failed to execute %s"), "/bin/sh");
+	xsetenv("SHELL", _PATH_BSHELL, 1);
+	execl(_PATH_BSHELL, profile ? "-sh" : "sh", (char *)NULL);
+	warn(_("failed to execute %s"), _PATH_BSHELL);
 }
 
 #ifdef HAVE_LIBSELINUX
diff --git a/sys-utils/setpriv.c b/sys-utils/setpriv.c
index c218be8e5..505d1ee5b 100644
--- a/sys-utils/setpriv.c
+++ b/sys-utils/setpriv.c
@@ -30,6 +30,7 @@
 #include <sys/prctl.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include <paths.h>
 
 #include "all-io.h"
 #include "c.h"
@@ -56,9 +57,6 @@
 
 #define SETPRIV_EXIT_PRIVERR 127	/* how we exit when we fail to set privs */
 
-/* The shell to set SHELL env.variable if none is given in the user's passwd entry.  */
-#define DEFAULT_SHELL "/bin/sh"
-
 static gid_t get_group(const char *s, const char *err);
 
 enum cap_type {
@@ -741,7 +739,7 @@ static void do_reset_environ(struct passwd *pw)
 	if (pw->pw_shell && *pw->pw_shell)
 		xsetenv("SHELL", pw->pw_shell, 1);
 	else
-		xsetenv("SHELL", DEFAULT_SHELL, 1);
+		xsetenv("SHELL", _PATH_BSHELL, 1);
 
 	xsetenv("HOME", pw->pw_dir, 1);
 	xsetenv("USER", pw->pw_name, 1);
-- 
2.51.1