libc/winsup/cygwin/passwd.cc

/* passwd.cc: getpwnam () and friends

   Copyright 1996, 1997, 1998, 2001, 2002, 2003, 2007, 2008, 2009,
   2010, 2011, 2012 Red Hat, Inc.

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

#include "winsup.h"
#include <stdlib.h>
#include <stdio.h>
#include "cygerrno.h"
#include "security.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "pinfo.h"
#include "cygheap.h"
#include "pwdgrp.h"
#include "shared_info.h"

/* Read /etc/passwd only once for better performance.  This is done
   on the first call that needs information from it. */

passwd *passwd_buf;
static pwdgrp pr (passwd_buf);

/* Parse /etc/passwd line into passwd structure. */
bool
pwdgrp::parse_passwd ()
{
  passwd &res = (*passwd_buf)[curr_lines];
  res.pw_name = next_str (':');
  res.pw_passwd = next_str (':');
  if (!next_num (res.pw_uid))
    return false;
  if (!next_num (res.pw_gid))
    return false;
  res.pw_comment = NULL;
  res.pw_gecos = next_str (':');
  res.pw_dir =  next_str (':');
  res.pw_shell = next_str (':');
  return true;
}

/* Read in /etc/passwd and save contents in the password cache.
   This sets pr to loaded or emulated so functions in this file can
   tell that /etc/passwd has been read in or will be emulated. */
void
pwdgrp::read_passwd ()
{
  load (L"\\etc\\passwd");

  char strbuf[128] = "";
  bool searchentry = true;
  struct passwd *pw;
  /* must be static */
  static char NO_COPY pretty_ls[] = "????????:*:-1:-1:::";

  add_line (pretty_ls);
  cygsid tu = cygheap->user.sid ();
  tu.string (strbuf);
  if (!user_shared->cb || myself->uid == ILLEGAL_UID)
    searchentry = !internal_getpwsid (tu);
  if (searchentry
      && (!(pw = internal_getpwnam (cygheap->user.name ()))
	  || !user_shared->cb
	  || (myself->uid != ILLEGAL_UID
	      && myself->uid != (__uid32_t) pw->pw_uid
	      && !internal_getpwuid (myself->uid))))
    {
      static char linebuf[1024];	// must be static and
					// should not be NO_COPY
      snprintf (linebuf, sizeof (linebuf), "%s:*:%lu:%lu:,%s:%s:/bin/sh",
		cygheap->user.name (),
		(!user_shared->cb || myself->uid == ILLEGAL_UID)
		? UNKNOWN_UID : myself->uid,
		!user_shared->cb ? UNKNOWN_GID : myself->gid,
		strbuf, getenv ("HOME") ?: "");
      debug_printf ("Completing /etc/passwd: %s", linebuf);
      add_line (linebuf);
    }
}

struct passwd *
internal_getpwsid (cygpsid &sid)
{
  struct passwd *pw;
  char *ptr1, *ptr2, *endptr;
  char sid_string[128] = {0,','};

  pr.refresh (false);

  if (sid.string (sid_string + 2))
    {
      endptr = strchr (sid_string + 2, 0) - 1;
      for (int i = 0; i < pr.curr_lines; i++)
	{
	  pw = passwd_buf + i;
	  if (pw->pw_dir > pw->pw_gecos + 8)
	    for (ptr1 = endptr, ptr2 = pw->pw_dir - 2;
		 *ptr1 == *ptr2; ptr2--)
	      if (!*--ptr1)
		return pw;
	}
    }
  return NULL;
}

struct passwd *
internal_getpwuid (__uid32_t uid, bool check)
{
  pr.refresh (check);

  for (int i = 0; i < pr.curr_lines; i++)
    if (uid == (__uid32_t) passwd_buf[i].pw_uid)
      return passwd_buf + i;
  return NULL;
}

struct passwd *
internal_getpwnam (const char *name, bool check)
{
  pr.refresh (check);

  for (int i = 0; i < pr.curr_lines; i++)
    /* on Windows NT user names are case-insensitive */
    if (strcasematch (name, passwd_buf[i].pw_name))
      return passwd_buf + i;
  return NULL;
}


extern "C" struct passwd *
getpwuid32 (__uid32_t uid)
{
  struct passwd *temppw = internal_getpwuid (uid, true);
  pthread_testcancel ();
  return temppw;
}

extern "C" struct passwd *
getpwuid (__uid16_t uid)
{
  return getpwuid32 (uid16touid32 (uid));
}

extern "C" int
getpwuid_r32 (__uid32_t uid, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result)
{
  *result = NULL;

  if (!pwd || !buffer)
    return ERANGE;

  struct passwd *temppw = internal_getpwuid (uid, true);
  pthread_testcancel ();
  if (!temppw)
    return 0;

  /* check needed buffer size. */
  size_t needsize = strlen (temppw->pw_name) + strlen (temppw->pw_passwd)
		    + strlen (temppw->pw_gecos) + strlen (temppw->pw_dir)
		    + strlen (temppw->pw_shell) + 5;
  if (needsize > bufsize)
    return ERANGE;

  /* make a copy of temppw */
  *result = pwd;
  pwd->pw_uid = temppw->pw_uid;
  pwd->pw_gid = temppw->pw_gid;
  buffer = stpcpy (pwd->pw_name = buffer, temppw->pw_name);
  buffer = stpcpy (pwd->pw_passwd = buffer + 1, temppw->pw_passwd);
  buffer = stpcpy (pwd->pw_gecos = buffer + 1, temppw->pw_gecos);
  buffer = stpcpy (pwd->pw_dir = buffer + 1, temppw->pw_dir);
  stpcpy (pwd->pw_shell = buffer + 1, temppw->pw_shell);
  pwd->pw_comment = NULL;
  return 0;
}

extern "C" int
getpwuid_r (__uid16_t uid, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result)
{
  return getpwuid_r32 (uid16touid32 (uid), pwd, buffer, bufsize, result);
}

extern "C" struct passwd *
getpwnam (const char *name)
{
  struct passwd *temppw = internal_getpwnam (name, true);
  pthread_testcancel ();
  return temppw;
}


/* the max size buffer we can expect to
 * use is returned via sysconf with _SC_GETPW_R_SIZE_MAX.
 * This may need updating! - Rob Collins April 2001.
 */
extern "C" int
getpwnam_r (const char *nam, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result)
{
  *result = NULL;

  if (!pwd || !buffer || !nam)
    return ERANGE;

  struct passwd *temppw = internal_getpwnam (nam, true);
  pthread_testcancel ();

  if (!temppw)
    return 0;

  /* check needed buffer size. */
  size_t needsize = strlen (temppw->pw_name) + strlen (temppw->pw_passwd)
		    + strlen (temppw->pw_gecos) + strlen (temppw->pw_dir)
		    + strlen (temppw->pw_shell) + 5;
  if (needsize > bufsize)
    return ERANGE;

  /* make a copy of temppw */
  *result = pwd;
  pwd->pw_uid = temppw->pw_uid;
  pwd->pw_gid = temppw->pw_gid;
  buffer = stpcpy (pwd->pw_name = buffer, temppw->pw_name);
  buffer = stpcpy (pwd->pw_passwd = buffer + 1, temppw->pw_passwd);
  buffer = stpcpy (pwd->pw_gecos = buffer + 1, temppw->pw_gecos);
  buffer = stpcpy (pwd->pw_dir = buffer + 1, temppw->pw_dir);
  stpcpy (pwd->pw_shell = buffer + 1, temppw->pw_shell);
  pwd->pw_comment = NULL;
  return 0;
}

extern "C" struct passwd *
getpwent (void)
{
  if (_my_tls.locals.pw_pos == 0)
    pr.refresh (true);
  if (_my_tls.locals.pw_pos < pr.curr_lines)
    return passwd_buf + _my_tls.locals.pw_pos++;

  return NULL;
}

extern "C" struct passwd *
getpwduid (__uid16_t)
{
  return NULL;
}

extern "C" void
setpwent (void)
{
  _my_tls.locals.pw_pos = 0;
}

extern "C" void
endpwent (void)
{
  _my_tls.locals.pw_pos = 0;
}

extern "C" int
setpassent ()
{
  return 0;
}

static void
_getpass_close_fd (void *arg)
{
  if (arg)
    fclose ((FILE *) arg);
}

extern "C" char *
getpass (const char * prompt)
{
  char *pass = _my_tls.locals.pass;
  struct termios ti, newti;
  bool tc_set = false;

  /* Try to use controlling tty in the first place.  Use stdin and stderr
     only as fallback. */
  FILE *in = stdin, *err = stderr;
  FILE *tty = fopen ("/dev/tty", "w+b");
  pthread_cleanup_push  (_getpass_close_fd, tty);
  if (tty)
    {
      /* Set close-on-exec for obvious reasons. */
      fcntl (fileno (tty), F_SETFD, fcntl (fileno (tty), F_GETFD) | FD_CLOEXEC);
      in = err = tty;
    }

  /* Make sure to notice if stdin is closed. */
  if (fileno (in) >= 0)
    {
      flockfile (in);
      /* Change tty attributes if possible. */
      if (!tcgetattr (fileno (in), &ti))
	{
	  newti = ti;
	  newti.c_lflag &= ~(ECHO | ISIG); /* No echo, no signal handling. */
	  if (!tcsetattr (fileno (in), TCSANOW, &newti))
	    tc_set = true;
	}
      fputs (prompt, err);
      fflush (err);
      fgets (pass, _PASSWORD_LEN, in);
      fprintf (err, "\n");
      if (tc_set)
	tcsetattr (fileno (in), TCSANOW, &ti);
      funlockfile (in);
      char *crlf = strpbrk (pass, "\r\n");
      if (crlf)
	*crlf = '\0';
    }
  pthread_cleanup_pop (1);
  return pass;
}