winsup/cygwin/passwd.cc

   1 /* passwd.cc: getpwnam () and friends
   2
   3    Copyright 1996, 1997, 1998, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008,
   4    2009, 2010, 2011, 2012 Red Hat, Inc.
   5
   6 This file is part of Cygwin.
   7
   8 This software is a copyrighted work licensed under the terms of the
   9 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
  10 details. */
  11
  12 #include "winsup.h"
  13 #include <stdlib.h>
  14 #include <stdio.h>
  15 #include "cygerrno.h"
  16 #include "security.h"
  17 #include "path.h"
  18 #include "fhandler.h"
  19 #include "dtable.h"
  20 #include "pinfo.h"
  21 #include "cygheap.h"
  22 #include "pwdgrp.h"
  23 #include "shared_info.h"
  24
  25 /* Read /etc/passwd only once for better performance.  This is done
  26    on the first call that needs information from it. */
  27
  28 passwd *passwd_buf;
  29 static pwdgrp pr (passwd_buf);
  30
  31 /* Parse /etc/passwd line into passwd structure. */
  32 bool
  33 pwdgrp::parse_passwd ()
  34 {
  35   passwd &res = (*passwd_buf)[curr_lines];
  36   res.pw_name = next_str (':');
  37   res.pw_passwd = next_str (':');
  38   if (!next_num (res.pw_uid))
  39     return false;
  40   if (!next_num (res.pw_gid))
  41     return false;
  42   res.pw_comment = NULL;
  43   res.pw_gecos = next_str (':');
  44   res.pw_dir =  next_str (':');
  45   res.pw_shell = next_str (':');
  46   return true;
  47 }
  48
  49 /* Read in /etc/passwd and save contents in the password cache.
  50    This sets pr to loaded or emulated so functions in this file can
  51    tell that /etc/passwd has been read in or will be emulated. */
  52 void
  53 pwdgrp::read_passwd ()
  54 {
  55   load (L"\\etc\\passwd");
  56
  57   char strbuf[128] = "";
  58   bool searchentry = true;
  59   struct passwd *pw;
  60   /* must be static */
  61   static char NO_COPY pretty_ls[] = "????????:*:-1:-1:::";
  62
  63   add_line (pretty_ls);
  64   cygsid tu = cygheap->user.sid ();
  65   tu.string (strbuf);
  66   if (!user_shared->cb || myself->uid == ILLEGAL_UID)
  67     searchentry = !internal_getpwsid (tu);
  68   if (searchentry
  69       && (!(pw = internal_getpwnam (cygheap->user.name ()))
  70           || !user_shared->cb
  71           || (myself->uid != ILLEGAL_UID
  72               && myself->uid != (__uid32_t) pw->pw_uid
  73               && !internal_getpwuid (myself->uid))))
  74     {
  75       static char linebuf[1024];        // must be static and
  76                                         // should not be NO_COPY
  77       snprintf (linebuf, sizeof (linebuf), "%s:*:%lu:%lu:,%s:%s:/bin/sh",
  78                 cygheap->user.name (),
  79                 (!user_shared->cb || myself->uid == ILLEGAL_UID)
  80                 ? UNKNOWN_UID : myself->uid,
  81                 !user_shared->cb ? UNKNOWN_GID : myself->gid,
  82                 strbuf, getenv ("HOME") ?: "");
  83       debug_printf ("Completing /etc/passwd: %s", linebuf);
  84       add_line (linebuf);
  85     }
  86 }
  87
  88 struct passwd *
  89 internal_getpwsid (cygpsid &sid)
  90 {
  91   struct passwd *pw;
  92   char *ptr1, *ptr2, *endptr;
  93   char sid_string[128] = {0,','};
  94
  95   pr.refresh (false);
  96
  97   if (sid.string (sid_string + 2))
  98     {
  99       endptr = strchr (sid_string + 2, 0) - 1;
 100       for (int i = 0; i < pr.curr_lines; i++)
 101         {
 102           pw = passwd_buf + i;
 103           if (pw->pw_dir > pw->pw_gecos + 8)
 104             for (ptr1 = endptr, ptr2 = pw->pw_dir - 2;
 105                  *ptr1 == *ptr2; ptr2--)
 106               if (!*--ptr1)
 107                 return pw;
 108         }
 109     }
 110   return NULL;
 111 }
 112
 113 struct passwd *
 114 internal_getpwuid (__uid32_t uid, bool check)
 115 {
 116   pr.refresh (check);
 117
 118   for (int i = 0; i < pr.curr_lines; i++)
 119     if (uid == (__uid32_t) passwd_buf[i].pw_uid)
 120       return passwd_buf + i;
 121   return NULL;
 122 }
 123
 124 struct passwd *
 125 internal_getpwnam (const char *name, bool check)
 126 {
 127   pr.refresh (check);
 128
 129   for (int i = 0; i < pr.curr_lines; i++)
 130     /* on Windows NT user names are case-insensitive */
 131     if (strcasematch (name, passwd_buf[i].pw_name))
 132       return passwd_buf + i;
 133   return NULL;
 134 }
 135
 136
 137 extern "C" struct passwd *
 138 getpwuid32 (__uid32_t uid)
 139 {
 140   struct passwd *temppw = internal_getpwuid (uid, true);
 141   pthread_testcancel ();
 142   return temppw;
 143 }
 144
 145 extern "C" struct passwd *
 146 getpwuid (__uid16_t uid)
 147 {
 148   return getpwuid32 (uid16touid32 (uid));
 149 }
 150
 151 extern "C" int
 152 getpwuid_r32 (__uid32_t uid, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result)
 153 {
 154   *result = NULL;
 155
 156   if (!pwd || !buffer)
 157     return ERANGE;
 158
 159   struct passwd *temppw = internal_getpwuid (uid, true);
 160   pthread_testcancel ();
 161   if (!temppw)
 162     return 0;
 163
 164   /* check needed buffer size. */
 165   size_t needsize = strlen (temppw->pw_name) + strlen (temppw->pw_passwd)
 166                     + strlen (temppw->pw_gecos) + strlen (temppw->pw_dir)
 167                     + strlen (temppw->pw_shell) + 5;
 168   if (needsize > bufsize)
 169     return ERANGE;
 170
 171   /* make a copy of temppw */
 172   *result = pwd;
 173   pwd->pw_uid = temppw->pw_uid;
 174   pwd->pw_gid = temppw->pw_gid;
 175   buffer = stpcpy (pwd->pw_name = buffer, temppw->pw_name);
 176   buffer = stpcpy (pwd->pw_passwd = buffer + 1, temppw->pw_passwd);
 177   buffer = stpcpy (pwd->pw_gecos = buffer + 1, temppw->pw_gecos);
 178   buffer = stpcpy (pwd->pw_dir = buffer + 1, temppw->pw_dir);
 179   stpcpy (pwd->pw_shell = buffer + 1, temppw->pw_shell);
 180   pwd->pw_comment = NULL;
 181   return 0;
 182 }
 183
 184 extern "C" int
 185 getpwuid_r (__uid16_t uid, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result)
 186 {
 187   return getpwuid_r32 (uid16touid32 (uid), pwd, buffer, bufsize, result);
 188 }
 189
 190 extern "C" struct passwd *
 191 getpwnam (const char *name)
 192 {
 193   struct passwd *temppw = internal_getpwnam (name, true);
 194   pthread_testcancel ();
 195   return temppw;
 196 }
 197
 198
 199 /* the max size buffer we can expect to
 200  * use is returned via sysconf with _SC_GETPW_R_SIZE_MAX.
 201  * This may need updating! - Rob Collins April 2001.
 202  */
 203 extern "C" int
 204 getpwnam_r (const char *nam, struct passwd *pwd, char *buffer, size_t bufsize, struct passwd **result)
 205 {
 206   *result = NULL;
 207
 208   if (!pwd || !buffer || !nam)
 209     return ERANGE;
 210
 211   struct passwd *temppw = internal_getpwnam (nam, true);
 212   pthread_testcancel ();
 213
 214   if (!temppw)
 215     return 0;
 216
 217   /* check needed buffer size. */
 218   size_t needsize = strlen (temppw->pw_name) + strlen (temppw->pw_passwd)
 219                     + strlen (temppw->pw_gecos) + strlen (temppw->pw_dir)
 220                     + strlen (temppw->pw_shell) + 5;
 221   if (needsize > bufsize)
 222     return ERANGE;
 223
 224   /* make a copy of temppw */
 225   *result = pwd;
 226   pwd->pw_uid = temppw->pw_uid;
 227   pwd->pw_gid = temppw->pw_gid;
 228   buffer = stpcpy (pwd->pw_name = buffer, temppw->pw_name);
 229   buffer = stpcpy (pwd->pw_passwd = buffer + 1, temppw->pw_passwd);
 230   buffer = stpcpy (pwd->pw_gecos = buffer + 1, temppw->pw_gecos);
 231   buffer = stpcpy (pwd->pw_dir = buffer + 1, temppw->pw_dir);
 232   stpcpy (pwd->pw_shell = buffer + 1, temppw->pw_shell);
 233   pwd->pw_comment = NULL;
 234   return 0;
 235 }
 236
 237 extern "C" struct passwd *
 238 getpwent (void)
 239 {
 240   if (_my_tls.locals.pw_pos == 0)
 241     pr.refresh (true);
 242   if (_my_tls.locals.pw_pos < pr.curr_lines)
 243     return passwd_buf + _my_tls.locals.pw_pos++;
 244
 245   return NULL;
 246 }
 247
 248 extern "C" struct passwd *
 249 getpwduid (__uid16_t)
 250 {
 251   return NULL;
 252 }
 253
 254 extern "C" void
 255 setpwent (void)
 256 {
 257   _my_tls.locals.pw_pos = 0;
 258 }
 259
 260 extern "C" void
 261 endpwent (void)
 262 {
 263   _my_tls.locals.pw_pos = 0;
 264 }
 265
 266 extern "C" int
 267 setpassent ()
 268 {
 269   return 0;
 270 }
 271
 272 static void
 273 _getpass_close_fd (void *arg)
 274 {
 275   if (arg)
 276     fclose ((FILE *) arg);
 277 }
 278
 279 extern "C" char *
 280 getpass (const char * prompt)
 281 {
 282   char *pass = _my_tls.locals.pass;
 283   struct termios ti, newti;
 284   bool tc_set = false;
 285
 286   /* Try to use controlling tty in the first place.  Use stdin and stderr
 287      only as fallback. */
 288   FILE *in = stdin, *err = stderr;
 289   FILE *tty = fopen ("/dev/tty", "w+b");
 290   pthread_cleanup_push  (_getpass_close_fd, tty);
 291   if (tty)
 292     {
 293       /* Set close-on-exec for obvious reasons. */
 294       fcntl (fileno (tty), F_SETFD, fcntl (fileno (tty), F_GETFD) | FD_CLOEXEC);
 295       in = err = tty;
 296     }
 297
 298   /* Make sure to notice if stdin is closed. */
 299   if (fileno (in) >= 0)
 300     {
 301       flockfile (in);
 302       /* Change tty attributes if possible. */
 303       if (!tcgetattr (fileno (in), &ti))
 304         {
 305           newti = ti;
 306           newti.c_lflag &= ~(ECHO | ISIG); /* No echo, no signal handling. */
 307           if (!tcsetattr (fileno (in), TCSANOW, &newti))
 308             tc_set = true;
 309         }
 310       fputs (prompt, err);
 311       fflush (err);
 312       fgets (pass, _PASSWORD_LEN, in);
 313       fprintf (err, "\n");
 314       if (tc_set)
 315         tcsetattr (fileno (in), TCSANOW, &ti);
 316       funlockfile (in);
 317       char *crlf = strpbrk (pass, "\r\n");
 318       if (crlf)
 319         *crlf = '\0';
 320     }
 321   pthread_cleanup_pop (1);
 322   return pass;
 323 }