libc/winsup/cygwin/grp.cc

/* grp.cc

   Copyright 1996, 1997, 1998, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
   2007, 2008, 2009 Red Hat, Inc.

   Original stubs by Jason Molenda of Cygnus Support, crash@cygnus.com
   First implementation by Gunther Ebert, gunther.ebert@ixos-leipzig.de

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

static __group32 *group_buf;
static pwdgrp gr (group_buf);
static char * NO_COPY null_ptr;

bool
pwdgrp::parse_group ()
{
# define grp (*group_buf)[curr_lines]
  grp.gr_name = next_str (':');
  if (!*grp.gr_name)
    return false;

  grp.gr_passwd = next_str (':');

  if (!next_num (grp.gr_gid))
    return false;

  int n;
  char *dp = raw_ptr ();
  for (n = 0; *next_str (','); n++)
    continue;

  grp.gr_mem = &null_ptr;
  if (n)
    {
      char **namearray = (char **) calloc (n + 1, sizeof (char *));
      if (namearray)
	{
	  for (int i = 0; i < n; i++, dp = strchr (dp, '\0') + 1)
	    namearray[i] = dp;
	  grp.gr_mem = namearray;
	}
    }

  return true;
# undef grp
}

/* Cygwin internal */
/* Read in /etc/group and save contents in the group cache */
/* This sets group_in_memory_p to 1 so functions in this file can
   tell that /etc/group has been read in */
void
pwdgrp::read_group ()
{
  for (int i = 0; i < gr.curr_lines; i++)
    if ((*group_buf)[i].gr_mem != &null_ptr)
      free ((*group_buf)[i].gr_mem);

  load (L"\\etc\\group");

  /* Complete /etc/group in memory if needed */
  if (!internal_getgrgid (myself->gid))
    {
      static char linebuf [200];
      char group_name [UNLEN + 1] = "mkgroup";
      char strbuf[128] = "";
      struct __group32 *gr;

      cygheap->user.groups.pgsid.string (strbuf);
      if ((gr = internal_getgrsid (cygheap->user.groups.pgsid)))
	snprintf (group_name, sizeof (group_name),
		  "passwd/group_GID_clash(%lu/%lu)", myself->gid, gr->gr_gid);
      if (myself->uid == UNKNOWN_UID)
	strcpy (group_name, "mkpasswd"); /* Feedback... */
      snprintf (linebuf, sizeof (linebuf), "%s:%s:%lu:%s",
		group_name, strbuf, myself->gid, cygheap->user.name ());
      debug_printf ("Completing /etc/group: %s", linebuf);
      add_line (linebuf);
    }
  static char NO_COPY pretty_ls[] = "????????::-1:";
  add_line (pretty_ls);
}

muto NO_COPY pwdgrp::pglock;

pwdgrp::pwdgrp (passwd *&pbuf) :
  pwdgrp_buf_elem_size (sizeof (*pbuf)), passwd_buf (&pbuf)
{
  read = &pwdgrp::read_passwd;
  parse = &pwdgrp::parse_passwd;
  pglock.init ("pglock");
}

pwdgrp::pwdgrp (__group32 *&gbuf) :
  pwdgrp_buf_elem_size (sizeof (*gbuf)), group_buf (&gbuf)
{
  read = &pwdgrp::read_group;
  parse = &pwdgrp::parse_group;
  pglock.init ("pglock");
}

struct __group32 *
internal_getgrsid (cygpsid &sid)
{
  char sid_string[128];

  gr.refresh (false);

  if (sid.string (sid_string))
    for (int i = 0; i < gr.curr_lines; i++)
      if (!strcmp (sid_string, group_buf[i].gr_passwd))
	return group_buf + i;
  return NULL;
}

struct __group32 *
internal_getgrgid (__gid32_t gid, bool check)
{
  gr.refresh (check);

  for (int i = 0; i < gr.curr_lines; i++)
    if (group_buf[i].gr_gid == gid)
      return group_buf + i;
  return NULL;
}

struct __group32 *
internal_getgrnam (const char *name, bool check)
{
  gr.refresh (check);

  for (int i = 0; i < gr.curr_lines; i++)
    if (strcasematch (group_buf[i].gr_name, name))
      return group_buf + i;

  /* Didn't find requested group */
  return NULL;
}

static struct __group16 *
grp32togrp16 (struct __group16 *gp16, struct __group32 *gp32)
{
  if (!gp16 || !gp32)
    return NULL;

  /* Copying the pointers is actually unnecessary.  Just having the correct
     return type is important. */
  gp16->gr_name = gp32->gr_name;
  gp16->gr_passwd = gp32->gr_passwd;
  gp16->gr_gid = (__gid16_t) gp32->gr_gid;		/* Not loss-free */
  gp16->gr_mem = gp32->gr_mem;

  return gp16;
}

extern "C" int
getgrgid_r (__gid32_t gid, struct __group32 *grp, char *buffer, size_t bufsize,
	    struct __group32 **result)
{
  *result = NULL;

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

  struct __group32 *tempgr = internal_getgrgid (gid, true);
  pthread_testcancel ();
  if (!tempgr)
    return 0;

  /* check needed buffer size. */
  int i;
  size_t needsize = strlen (tempgr->gr_name) + strlen (tempgr->gr_passwd)
		    + 2 + sizeof (char *);
  for (i = 0; tempgr->gr_mem[i]; ++i)
    needsize += strlen (tempgr->gr_mem[i]) + 1 + sizeof (char *);
  if (needsize > bufsize)
    return ERANGE;

  /* make a copy of tempgr */
  *result = grp;
  grp->gr_gid = tempgr->gr_gid;
  buffer = stpcpy (grp->gr_name = buffer, tempgr->gr_name);
  buffer = stpcpy (grp->gr_passwd = buffer + 1, tempgr->gr_passwd);
  grp->gr_mem = (char **) (buffer + 1);
  buffer = (char *) grp->gr_mem + (i + 1) * sizeof (char *);
  for (i = 0; tempgr->gr_mem[i]; ++i)
    buffer = stpcpy (grp->gr_mem[i] = buffer, tempgr->gr_mem[i]) + 1;
  grp->gr_mem[i] = NULL;
  return 0;
}

extern "C" struct __group32 *
getgrgid32 (__gid32_t gid)
{
  return internal_getgrgid (gid, true);
}

extern "C" struct __group16 *
getgrgid (__gid16_t gid)
{
  static struct __group16 g16;	/* FIXME: thread-safe? */

  return grp32togrp16 (&g16, getgrgid32 (gid16togid32 (gid)));
}

extern "C" int
getgrnam_r (const char *nam, struct __group32 *grp, char *buffer,
	    size_t bufsize, struct __group32 **result)
{
  *result = NULL;

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

  struct __group32 *tempgr = internal_getgrnam (nam, true);
  pthread_testcancel ();
  if (!tempgr)
    return 0;

  /* check needed buffer size. */
  int i;
  size_t needsize = strlen (tempgr->gr_name) + strlen (tempgr->gr_passwd)
		    + 2 + sizeof (char *);
  for (i = 0; tempgr->gr_mem[i]; ++i)
    needsize += strlen (tempgr->gr_mem[i]) + 1 + sizeof (char *);
  if (needsize > bufsize)
    return ERANGE;

  /* make a copy of tempgr */
  *result = grp;
  grp->gr_gid = tempgr->gr_gid;
  buffer = stpcpy (grp->gr_name = buffer, tempgr->gr_name);
  buffer = stpcpy (grp->gr_passwd = buffer + 1, tempgr->gr_passwd);
  grp->gr_mem = (char **) (buffer + 1);
  buffer = (char *) grp->gr_mem + (i + 1) * sizeof (char *);
  for (i = 0; tempgr->gr_mem[i]; ++i)
    buffer = stpcpy (grp->gr_mem[i] = buffer, tempgr->gr_mem[i]) + 1;
  grp->gr_mem[i] = NULL;
  return 0;
}

extern "C" struct __group32 *
getgrnam32 (const char *name)
{
  return internal_getgrnam (name, true);
}

extern "C" struct __group16 *
getgrnam (const char *name)
{
  static struct __group16 g16;	/* FIXME: thread-safe? */

  return grp32togrp16 (&g16, getgrnam32 (name));
}

extern "C" void
endgrent ()
{
  _my_tls.locals.grp_pos = 0;
}

extern "C" struct __group32 *
getgrent32 ()
{
  if (_my_tls.locals.grp_pos == 0)
    gr.refresh (true);
  if (_my_tls.locals.grp_pos < gr.curr_lines)
    return group_buf + _my_tls.locals.grp_pos++;

  return NULL;
}

extern "C" struct __group16 *
getgrent ()
{
  static struct __group16 g16;	/* FIXME: thread-safe? */

  return grp32togrp16 (&g16, getgrent32 ());
}

extern "C" void
setgrent ()
{
  _my_tls.locals.grp_pos = 0;
}

/* Internal function. ONLY USE THIS INTERNALLY, NEVER `getgrent'!!! */
struct __group32 *
internal_getgrent (int pos)
{
  gr.refresh (false);

  if (pos < gr.curr_lines)
    return group_buf + pos;
  return NULL;
}

int
internal_getgroups (int gidsetsize, __gid32_t *grouplist, cygpsid * srchsid)
{
  HANDLE hToken = NULL;
  DWORD size;
  int cnt = 0;
  struct __group32 *gr;

  if (!srchsid && cygheap->user.groups.issetgroups ())
    {
      cygsid sid;
      for (int gidx = 0; (gr = internal_getgrent (gidx)); ++gidx)
	if (sid.getfromgr (gr))
	  for (int pg = 0; pg < cygheap->user.groups.sgsids.count (); ++pg)
	    if (sid == cygheap->user.groups.sgsids.sids[pg]
		&& sid != well_known_world_sid)
	      {
		if (cnt < gidsetsize)
		  grouplist[cnt] = gr->gr_gid;
		++cnt;
		if (gidsetsize && cnt > gidsetsize)
		  goto error;
		break;
	      }
      return cnt;
    }


  /* If impersonated, use impersonation token. */
  if (cygheap->user.issetuid ())
    hToken = cygheap->user.primary_token ();
  else
    hToken = hProcToken;

  if (GetTokenInformation (hToken, TokenGroups, NULL, 0, &size)
      || GetLastError () == ERROR_INSUFFICIENT_BUFFER)
    {
      PTOKEN_GROUPS groups = (PTOKEN_GROUPS) alloca (size);

      if (GetTokenInformation (hToken, TokenGroups, groups, size, &size))
	{
	  cygsid sid;

	  if (srchsid)
	    {
	      for (DWORD pg = 0; pg < groups->GroupCount; ++pg)
		if ((cnt = (*srchsid == groups->Groups[pg].Sid)))
		  break;
	    }
	  else
	    for (int gidx = 0; (gr = internal_getgrent (gidx)); ++gidx)
	      if (sid.getfromgr (gr))
		for (DWORD pg = 0; pg < groups->GroupCount; ++pg)
		  if (sid == groups->Groups[pg].Sid
		      && (groups->Groups[pg].Attributes
			  & (SE_GROUP_ENABLED | SE_GROUP_INTEGRITY_ENABLED))
		      && sid != well_known_world_sid)
		    {
		      if (cnt < gidsetsize)
			grouplist[cnt] = gr->gr_gid;
		      ++cnt;
		      if (gidsetsize && cnt > gidsetsize)
			goto error;
		      break;
		    }
	}
    }
  else
    debug_printf ("%d = GetTokenInformation(NULL) %E", size);
  return cnt;

error:
  set_errno (EINVAL);
  return -1;
}

extern "C" int
getgroups32 (int gidsetsize, __gid32_t *grouplist)
{
  return internal_getgroups (gidsetsize, grouplist);
}

extern "C" int
getgroups (int gidsetsize, __gid16_t *grouplist)
{
  __gid32_t *grouplist32 = NULL;

  if (gidsetsize < 0)
    {
      set_errno (EINVAL);
      return -1;
    }
  if (gidsetsize > 0 && grouplist)
    grouplist32 = (__gid32_t *) alloca (gidsetsize * sizeof (__gid32_t));

  int ret = internal_getgroups (gidsetsize, grouplist32);

  if (gidsetsize > 0 && grouplist)
    for (int i = 0; i < ret; ++ i)
      grouplist[i] = grouplist32[i];

  return ret;
}

extern "C" int
initgroups32 (const char *name, __gid32_t gid)
{
  int ret = -1;

  cygheap->user.deimpersonate ();
  struct passwd *pw = internal_getpwnam (name);
  struct __group32 *gr = internal_getgrgid (gid);
  cygsid usersid, grpsid;
  if (!usersid.getfrompw (pw) || !grpsid.getfromgr (gr))
    set_errno (EINVAL);
  else
    {
      cygsidlist tmp_gsids (cygsidlist_auto, 12);
      if (get_server_groups (tmp_gsids, usersid, pw))
	{
	  tmp_gsids += grpsid;
	  cygsidlist new_gsids (cygsidlist_alloc, tmp_gsids.count ());
	  for (int i = 0; i < tmp_gsids.count (); i++)
	    new_gsids.sids[i] = tmp_gsids.sids[i];
	  new_gsids.count (tmp_gsids.count ());
	  cygheap->user.groups.update_supp (new_gsids);
	  ret = 0;
	}
    }
  cygheap->user.reimpersonate ();
  syscall_printf ( "%d = initgroups (%s, %u)", ret, name, gid);
  return ret;
}

extern "C" int
initgroups (const char *name, __gid16_t gid)
{
  return initgroups32 (name, gid16togid32(gid));
}

/* setgroups32: standards? */
extern "C" int
setgroups32 (int ngroups, const __gid32_t *grouplist)
{
  syscall_printf ("setgroups32 (%d)", ngroups);
  if (ngroups < 0 || (ngroups > 0 && !grouplist))
    {
      set_errno (EINVAL);
      return -1;
    }

  cygsidlist gsids (cygsidlist_alloc, ngroups);
  struct __group32 *gr;

  if (ngroups && !gsids.sids)
    return -1;

  for (int gidx = 0; gidx < ngroups; ++gidx)
    {
      if ((gr = internal_getgrgid (grouplist[gidx]))
	  && gsids.addfromgr (gr))
	continue;
      debug_printf ("No sid found for gid %d", grouplist[gidx]);
      gsids.free_sids ();
      set_errno (EINVAL);
      return -1;
    }
  cygheap->user.groups.update_supp (gsids);
  return 0;
}

extern "C" int
setgroups (int ngroups, const __gid16_t *grouplist)
{
  __gid32_t *grouplist32 = NULL;

  if (ngroups > 0 && grouplist)
    {
      grouplist32 = (__gid32_t *) alloca (ngroups * sizeof (__gid32_t));
      if (grouplist32 == NULL)
	return -1;
      for (int i = 0; i < ngroups; i++)
	grouplist32[i] = grouplist[i];
    }
  return setgroups32 (ngroups, grouplist32);
}