Do not fail password check if shadow password does not exist -

fall back to ordinary one

Reduced usage of functions returning datain static buffers.
(mostly passwd/group/shadow related):

function                                             old     new   delta
correct_password                                     143     193     +50
sulogin_main                                         490     533     +43
adduser_main                                         732     774     +42
passwd_main                                         1875    1915     +40
addgroup_main                                        330     365     +35
bb_internal_getspnam                                  38       -     -38
bb_internal_fgetpwent                                 38       -     -38
bb_internal_fgetgrent                                 38       -     -38
static.resultbuf                                     168      88     -80
static.buffer                                       1872    1104    -768
------------------------------------------------------------------------------
(add/remove: 0/3 grow/shrink: 5/2 up/down: 210/-962)         Total: -752 bytes

1 files changed, 15 insertions, 11 deletions

diff --git a/loginutils/passwd.c b/loginutils/passwd.c
index 4531e63a6..b937ce45e 100644
--- a/loginutils/passwd.c
+++ b/loginutils/passwd.c
@@ -252,6 +252,13 @@ int passwd_main(int argc, char **argv)
         struct rlimit rlimit_fsize;
         char c;
 
+#if ENABLE_FEATURE_SHADOWPASSWDS
+        /* Using _r function to avoid pulling in static buffers */
+        struct spwd spw;
+        struct spwd *result;
+        char buffer[256];
+#endif
+
         logmode = LOGMODE_BOTH;
         openlog(applet_name, LOG_NOWAIT, LOG_AUTH);
         opt = getopt32(argc, argv, "a:lud", &opt_a);
@@ -278,17 +285,14 @@ int passwd_main(int argc, char **argv)
 
         filename = bb_path_passwd_file;
 #if ENABLE_FEATURE_SHADOWPASSWDS
-        {
-                struct spwd *sp = getspnam(name);
-                if (!sp) {
-                        /* LOGMODE_BOTH */
-                        bb_error_msg("no record of %s in %s, using %s",
-                                        name, bb_path_shadow_file,
-                                        bb_path_passwd_file);
-                } else {
-                        filename = bb_path_shadow_file;
-                        pw->pw_passwd = sp->sp_pwdp;
-                }
+        if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result)) {
+                /* LOGMODE_BOTH */
+                bb_error_msg("no record of %s in %s, using %s",
+                                name, bb_path_shadow_file,
+                                bb_path_passwd_file);
+        } else {
+                filename = bb_path_shadow_file;
+                pw->pw_passwd = spw.sp_pwdp;
         }
 #endif