login: use const qualifier for username from PAM or struct passwd [-Wcast-qual]

It seems more robust to use 'const' qualifier for username if this
variable points to external resources like PAM or struct passwd. The
patch introduces new variable cmd_username for username specified on
login(1) command line.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/login-utils/login.c b/login-utils/login.c
index 09ee8f8eae2dde1e5a5741767e062a992d1d3c52..9aef3d804a3176bea031e55b1a217e5d6e7ba226 100644 (file)
--- a/login-utils/login.c
+++ b/login-utils/login.c
@@ -105,7 +105,9 @@ struct login_context {
        const char      *tty_number;    /* end of the tty_path */
        mode_t          tty_mode;       /* chmod() mode */
 
-       char            *username;      /* from command line or PAM */
+       const char      *username;      /* points to PAM, pwd or cmd_username */
+       char            *cmd_username;  /* username specified on command line */
+
 
        struct passwd   *pwd;           /* user info */
        char            *pwdbuf;        /* pwd strings */
@@ -655,12 +657,12 @@ static void log_syslog(struct login_context *cxt)
 }
 
 /* encapsulate stupid "void **" pam_get_item() API */
-static int loginpam_get_username(pam_handle_t *pamh, char **name)
+static int loginpam_get_username(pam_handle_t *pamh, const char **name)
 {
-       const void *item = (void *)*name;
+       const void *item = (const void *)*name;
        int rc;
        rc = pam_get_item(pamh, PAM_USER, &item);
-       *name = (char *)item;
+       *name = (const char *)item;
        return rc;
 }
 
@@ -740,7 +742,6 @@ static pam_handle_t *init_loginpam(struct login_context *cxt)
                loginpam_err(pamh, rc);
 
        /* We don't need the original username. We have to follow PAM. */
-       free(cxt->username);
        cxt->username = NULL;
        cxt->pamh = pamh;
 
@@ -1204,7 +1205,11 @@ int main(int argc, char **argv)
 
        if (*argv) {
                char *p = *argv;
-               cxt.username = xstrdup(p);
+
+               /* username from command line */
+               cxt.cmd_username = xstrdup(p);
+               /* used temporary, it'll be replaced by username from PAM or/and cxt->pwd */
+               cxt.username = cxt.cmd_username;
 
                /* Wipe the name - some people mistype their password here. */
                /* (Of course we are too late, but perhaps this helps a little...) */