# HG changeset patch
# User Ashwini Sharma <ak.ashwini1981@gmail.com>
# Date 1400960402 18000
# Node ID ff3ecf9e5095787c89b85b54622a42605b3d81e8
# Parent  726d3e67d8c14f1103b765582c9daac8c4234e09
Single-user login.

diff -r 726d3e67d8c1 -r ff3ecf9e5095 toys/pending/sulogin.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toys/pending/sulogin.c	Sat May 24 14:40:02 2014 -0500
@@ -0,0 +1,117 @@
+/* sulogin.c - Single User Login.
+ *
+ * Copyright 2014 Ashish Kumar Gupta <ashishkguptaiit.cse@gmail.com>
+ * Copyright 2014 Kyungwan Han <asura321@gmail.com>
+ *
+ * 
+ * Relies on libcrypt for hash calculation. 
+ * No support for PAM/securetty/selinux/login script/issue/utmp
+
+
+USE_SULOGIN(NEWTOY(sulogin, "t#<0=0", TOYFLAG_SBIN|TOYFLAG_NEEDROOT))
+
+config SULOGIN
+  bool "sulogin"
+  default y
+  help
+    usage: sulogin [-t time] [tty]
+
+    Single User Login.
+    -t	Default Time for Single User Login
+*/
+#define FOR_sulogin
+#include "toys.h"
+
+GLOBALS(
+  long timeout;
+  struct termios crntio;
+)
+
+static void timeout_handle(int signo) 
+{
+  tcsetattr(0, TCSANOW, &(TT.crntio));
+  fflush(stdout);
+  xprintf("\n Timed out - Normal startup\n");
+  exit(0);
+}
+
+static int validate_password(char *pwd)
+{
+  struct sigaction sa;
+  int ret;
+  char *s = "Give root password for system maintenance\n"
+    "(or type Control-D for normal startup):",
+    *pass;
+
+  tcgetattr(0, &(TT.crntio));
+  sa.sa_handler = timeout_handle;
+
+  if(TT.timeout) {
+    sigaction(SIGALRM, &sa, NULL);
+    alarm(TT.timeout);
+  }
+
+  ret = read_password(toybuf, sizeof(toybuf), s);
+  if(TT.timeout) alarm(0);
+
+  if ( ret && !toybuf[0]) {   
+    xprintf("Normal startup.\n");
+    return -1;
+  }
+
+  pass = crypt(toybuf, pwd);
+  ret = 1;
+  if( pass && !strcmp(pass, pwd)) ret = 0;
+
+  return ret;
+}
+
+static void run_shell(char *shell) 
+{
+  snprintf(toybuf,sizeof(toybuf), "-%s", shell);
+  execl(shell, toybuf, NULL);
+  error_exit("Failed to spawn shell");
+}
+
+void sulogin_main(void)
+{
+  struct passwd *pwd = NULL;
+  struct spwd * spwd = NULL;
+  char *forbid[] = {
+    "BASH_ENV", "ENV", "HOME", "IFS", "LD_LIBRARY_PATH", "LD_PRELOAD",
+    "LD_TRACE_LOADED_OBJECTS", "LD_BIND_NOW", "LD_AOUT_LIBRARY_PATH",
+    "LD_AOUT_PRELOAD", "LD_NOWARN", "LD_KEEPDIR", "SHELL", NULL
+  };
+  char *shell = NULL, *pass = NULL, **temp = forbid;
+
+  if (toys.optargs[0]) {
+    int fd;
+
+    dup2((fd = xopen(toys.optargs[0], O_RDWR)), 0);
+    if (!isatty(0)) error_exit("%s: it is not a tty", toys.optargs[0]);
+    dup2( fd, 1);
+    dup2( fd, 2);
+    if (fd > 2) close(fd);
+  }  
+
+  for (temp = forbid; *temp; temp++) unsetenv(*temp);
+
+  if (!(pwd = getpwuid(0))) error_exit("invalid user");
+  pass = pwd->pw_passwd;
+
+  if ((pass[0] == 'x' || pass[0] == '*') && !pass[1]) {
+    if ((spwd = getspnam (pwd->pw_name))) pass = spwd->sp_pwdp;
+  }
+
+  while (1) {
+    int r = validate_password(pass);
+
+    if (r == 1) xprintf("Incorrect Login.\n");
+    else if (r == 0) break;
+    else if (r == -1) return;
+  }
+
+  if ((shell = getenv("SUSHELL")) || (shell = getenv("sushell"))
+      || (shell = pwd->pw_shell))
+    run_shell((shell && *shell)? shell: "/bin/sh");
+}