1 files changed, 80 insertions, 0 deletions
diff --git a/libpam/pam_modutil_getlogin.c b/libpam/pam_modutil_getlogin.c
new file mode 100644
index 0000000..04a20fd
--- /dev/null
+++ b/libpam/pam_modutil_getlogin.c
@@ -0,0 +1,80 @@
+/*
+ * $Id$
+ *
+ * A central point for invoking getlogin(). Hopefully, this is a
+ * little harder to spoof than all the other versions that are out
+ * there.
+ */
+
+#include "pam_modutil_private.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <utmp.h>
+
+#define _PAMMODUTIL_GETLOGIN "_pammodutil_getlogin"
+
+const char *
+pam_modutil_getlogin(pam_handle_t *pamh)
+{
+    int status;
+    const void *logname;
+    const void *void_curr_tty;
+    const char *curr_tty;
+    char *curr_user;
+    struct utmp *ut, line;
+
+    status = pam_get_data(pamh, _PAMMODUTIL_GETLOGIN, &logname);
+    if (status == PAM_SUCCESS) {
+	return logname;
+    }
+
+    status = pam_get_item(pamh, PAM_TTY, &void_curr_tty);
+    if ((status != PAM_SUCCESS) || (void_curr_tty == NULL))
+      curr_tty = ttyname(0);
+    else
+      curr_tty = (const char*)void_curr_tty;
+
+    if (curr_tty == NULL) {
+	return NULL;
+    }
+
+    if (curr_tty[0] == '/') {   /* full path */
+        const char *t;
+	curr_tty++;
+	if ((t = strchr(curr_tty, '/')) != NULL) {
+	  curr_tty = t + 1;
+	}
+    }
+    logname = NULL;
+
+    setutent();
+    strncpy(line.ut_line, curr_tty, sizeof(line.ut_line));
+
+    if ((ut = getutline(&line)) == NULL) {
+	goto clean_up_and_go_home;
+    }
+
+    curr_user = calloc(sizeof(line.ut_user)+1, 1);
+    if (curr_user == NULL) {
+	goto clean_up_and_go_home;
+    }
+
+    strncpy(curr_user, ut->ut_user, sizeof(ut->ut_user));
+    /* calloc already zeroed the memory */
+
+    status = pam_set_data(pamh, _PAMMODUTIL_GETLOGIN, curr_user,
+			  pam_modutil_cleanup);
+    if (status != PAM_SUCCESS) {
+	free(curr_user);
+	goto clean_up_and_go_home;
+    }
+
+    logname = curr_user;
+
+clean_up_and_go_home:
+
+    endutent();
+
+    return logname;
+}