/* external.cc: Interface to Cygwin internals from external programs.

   Copyright 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
   2008, 2009, 2010, 2011, 2012 Red Hat, Inc.

   Written by Christopher Faylor <cgf@cygnus.com>

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 "sigproc.h"
#include "pinfo.h"
#include "shared_info.h"
#include "cygwin_version.h"
#include "cygerrno.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "heap.h"
#include "cygtls.h"
#include "child_info.h"
#include "environ.h"
#include "cygserver_setpwd.h"
#include <unistd.h>
#include <stdlib.h>
#include <wchar.h>
#include <iptypes.h>
#include <cygwin/callout.h>

child_info *get_cygwin_startup_info ();
static void exit_process (UINT, bool) __attribute__((noreturn));

static winpids pids;

static external_pinfo *
fillout_pinfo (pid_t pid, int winpid)
{
  BOOL nextpid;
  static external_pinfo ep;
  static char ep_progname_long_buf[NT_MAX_PATH];

  if ((nextpid = !!(pid & CW_NEXTPID)))
    pid ^= CW_NEXTPID;


  static unsigned int i;
  if (!pids.npids || !nextpid)
    {
      pids.set (winpid);
      i = 0;
    }

  if (!pid)
    i = 0;

  memset (&ep, 0, sizeof ep);
  while (i < pids.npids)
    {
      DWORD thispid = pids.winpid (i);
      _pinfo *p = pids[i];
      i++;

      if (!p)
	{
	  if (!nextpid && thispid != (DWORD) pid)
	    continue;
	  ep.pid = cygwin_pid (thispid);
	  ep.dwProcessId = thispid;
	  ep.process_state = PID_IN_USE;
	  ep.ctty = -1;
	  break;
	}
      else if (nextpid || p->pid == pid || (winpid && thispid == (DWORD) pid))
	{
	  ep.ctty = (p->ctty < 0 || iscons_dev (p->ctty)) ? p->ctty : device::minor (p->ctty);
	  ep.pid = p->pid;
	  ep.ppid = p->ppid;
	  ep.dwProcessId = p->dwProcessId;
	  ep.uid = p->uid;
	  ep.gid = p->gid;
	  ep.pgid = p->pgid;
	  ep.sid = p->sid;
	  ep.umask = 0;
	  ep.start_time = p->start_time;
	  ep.rusage_self = p->rusage_self;
	  ep.rusage_children = p->rusage_children;
	  ep.progname[0] = '\0';
	  sys_wcstombs(ep.progname, MAX_PATH, p->progname);
	  ep.strace_mask = 0;
	  ep.version = EXTERNAL_PINFO_VERSION;

	  ep.process_state = p->process_state;

	  ep.uid32 = p->uid;
	  ep.gid32 = p->gid;

	  ep.progname_long = ep_progname_long_buf;
	  mount_table->conv_to_posix_path (p->progname, ep.progname_long, 0);
	  break;
	}
    }

  if (!ep.pid)
    {
      i = 0;
      pids.reset ();
      return NULL;
    }
  return &ep;
}

static inline uintptr_t
get_cygdrive_info (char *user, char *system, char *user_flags,
		   char *system_flags)
{
  int res = mount_table->get_cygdrive_info (user, system, user_flags,
					    system_flags);
  return (res == ERROR_SUCCESS) ? 1 : 0;
}

static bool
check_ntsec (const char *filename)
{
  if (!filename)
    return true;
  path_conv pc (filename);
  return pc.has_acls ();
}

/* Copy cygwin environment variables to the Windows environment. */
static PWCHAR
create_winenv (const char * const *env)
{
  int unused_envc;
  PWCHAR envblock = NULL;
  char **envp = build_env (env ?: cur_environ (), envblock, unused_envc, false);
  PWCHAR p = envblock;

  if (envp)
    {
      for (char **e = envp; *e; e++)
	cfree (*e);
      cfree (envp);
    }
  /* If we got an env block, just return pointer to win env. */
  if (env)
    return envblock;
  /* Otherwise sync win env of current process with its posix env. */
  if (!p)
    return NULL;
  while (*p)
    {
      PWCHAR eq = wcschr (p, L'=');
      if (eq)
	{
	  *eq = L'\0';
	  SetEnvironmentVariableW (p, ++eq);
	  p = eq;
	}
      p = wcschr (p, L'\0') + 1;
    }
  free (envblock);
  return NULL;
}

/*
 * Cygwin-specific wrapper for win32 ExitProcess and TerminateProcess.
 * It ensures that the correct exit code, derived from the specified
 * status value, will be made available to this process's parent (if
 * that parent is also a cygwin process). If useTerminateProcess is
 * true, then TerminateProcess(GetCurrentProcess(),...) will be used;
 * otherwise, ExitProcess(...) is called.
 *
 * Used by startup code for cygwin processes which is linked statically
 * into applications, and is not part of the cygwin DLL -- which is why
 * this interface is exposed. "Normal" programs should use ANSI exit(),
 * ANSI abort(), or POSIX _exit(), rather than this function -- because
 * calling ExitProcess or TerminateProcess, even through this wrapper,
 * skips much of the cygwin process cleanup code.
 */
static void
exit_process (UINT status, bool useTerminateProcess)
{
  pid_t pid = getpid ();
  external_pinfo *ep = fillout_pinfo (pid, 1);
  DWORD dwpid = ep ? ep->dwProcessId : pid;
  pinfo p (pid, PID_MAP_RW);
  if (ep)
    pid = ep->pid;
  if ((dwpid == GetCurrentProcessId()) && (p->pid == pid))
    p.set_exit_code ((DWORD)status);
  if (useTerminateProcess)
    TerminateProcess (GetCurrentProcess(), status);
  /* avoid 'else' clause to silence warning */
  ExitProcess (status);
}


extern "C" uintptr_t
cygwin_internal (cygwin_getinfo_types t, ...)
{
  va_list arg;
  uintptr_t res = (uintptr_t) -1;
  va_start (arg, t);

  switch (t)
    {
      case CW_LOCK_PINFO:
	res = 1;
	break;

      case CW_UNLOCK_PINFO:
	res = 1;
	break;

      case CW_GETTHREADNAME:
	res = (uintptr_t) cygthread::name (va_arg (arg, DWORD));
	break;

      case CW_SETTHREADNAME:
	{
	  set_errno (ENOSYS);
	  res = 0;
	}
	break;

      case CW_GETPINFO:
	res = (uintptr_t) fillout_pinfo (va_arg (arg, DWORD), 0);
	break;

      case CW_GETVERSIONINFO:
	res = (uintptr_t) cygwin_version_strings;
	break;

      case CW_READ_V1_MOUNT_TABLES:
	set_errno (ENOSYS);
	res = 1;
	break;

      case CW_USER_DATA:
	/* This is a kludge to work around a version of _cygwin_common_crt0
	   which overwrote the cxx_malloc field with the local DLL copy.
	   Hilarity ensues if the DLL is not loaded like while the process
	   is forking. */
	__cygwin_user_data.cxx_malloc = &default_cygwin_cxx_malloc;
	res = (uintptr_t) &__cygwin_user_data;
	break;

      case CW_PERFILE:
	perfile_table = va_arg (arg, struct __cygwin_perfile *);
	res = 0;
	break;

      case CW_GET_CYGDRIVE_PREFIXES:
	{
	  char *user = va_arg (arg, char *);
	  char *system = va_arg (arg, char *);
	  res = get_cygdrive_info (user, system, NULL, NULL);
	}
	break;

      case CW_GETPINFO_FULL:
	res = (uintptr_t) fillout_pinfo (va_arg (arg, pid_t), 1);
	break;

      case CW_INIT_EXCEPTIONS:
	/* noop */ /* init_exceptions (va_arg (arg, exception_list *)); */
	res = 0;
	break;

      case CW_GET_CYGDRIVE_INFO:
	{
	  char *user = va_arg (arg, char *);
	  char *system = va_arg (arg, char *);
	  char *user_flags = va_arg (arg, char *);
	  char *system_flags = va_arg (arg, char *);
	  res = get_cygdrive_info (user, system, user_flags, system_flags);
	}
	break;

      case CW_SET_CYGWIN_REGISTRY_NAME:
      case CW_GET_CYGWIN_REGISTRY_NAME:
	res = 0;
	break;

      case CW_STRACE_TOGGLE:
	{
	  pid_t pid = va_arg (arg, pid_t);
	  pinfo p (pid);
	  if (p)
	    {
	      sig_send (p, __SIGSTRACE);
	      res = 0;
	    }
	  else
	    {
	      set_errno (ESRCH);
	      res = (uintptr_t) -1;
	    }
	}
	break;

      case CW_STRACE_ACTIVE:
	{
	  res = strace.active ();
	}
	break;

      case CW_CYGWIN_PID_TO_WINPID:
	{
	  pinfo p (va_arg (arg, pid_t));
	  res = p ? p->dwProcessId : 0;
	}
	break;
      case CW_EXTRACT_DOMAIN_AND_USER:
	{
	  WCHAR nt_domain[MAX_DOMAIN_NAME_LEN + 1];
	  WCHAR nt_user[UNLEN + 1];

	  struct passwd *pw = va_arg (arg, struct passwd *);
	  char *domain = va_arg (arg, char *);
	  char *user = va_arg (arg, char *);
	  extract_nt_dom_user (pw, nt_domain, nt_user);
	  if (domain)
	    sys_wcstombs (domain, MAX_DOMAIN_NAME_LEN + 1, nt_domain);
	  if (user)
	    sys_wcstombs (user, UNLEN + 1, nt_user);
	  res = 0;
	}
	break;
      case CW_CMDLINE:
	{
	  size_t n;
	  pid_t pid = va_arg (arg, pid_t);
	  pinfo p (pid);
	  res = (uintptr_t) p->cmdline (n);
	}
	break;
      case CW_CHECK_NTSEC:
	{
	  char *filename = va_arg (arg, char *);
	  res = check_ntsec (filename);
	}
	break;
      case CW_GET_ERRNO_FROM_WINERROR:
	{
	  int error = va_arg (arg, int);
	  int deferrno = va_arg (arg, int);
	  res = geterrno_from_win_error (error, deferrno);
	}
	break;
      case CW_GET_POSIX_SECURITY_ATTRIBUTE:
	{
	  path_conv dummy;
	  security_descriptor sd;
	  int attribute = va_arg (arg, int);
	  PSECURITY_ATTRIBUTES psa = va_arg (arg, PSECURITY_ATTRIBUTES);
	  void *sd_buf = va_arg (arg, void *);
	  DWORD sd_buf_size = va_arg (arg, DWORD);
	  set_security_attribute (dummy, attribute, psa, sd);
	  if (!psa->lpSecurityDescriptor)
	    res = sd.size ();
	  else
	    {
	      psa->lpSecurityDescriptor = sd_buf;
	      res = sd.copy (sd_buf, sd_buf_size);
	    }
	}
	break;
      case CW_GET_SHMLBA:
	{
	  res = wincap.allocation_granularity ();
	}
	break;
      case CW_GET_UID_FROM_SID:
	{
	  cygpsid psid = va_arg (arg, PSID);
	  res = psid.get_id (false, NULL);
	}
	break;
      case CW_GET_GID_FROM_SID:
	{
	  cygpsid psid = va_arg (arg, PSID);
	  res = psid.get_id (true, NULL);
	}
	break;
      case CW_GET_BINMODE:
	{
	  const char *path = va_arg (arg, const char *);
	  path_conv p (path, PC_SYM_FOLLOW | PC_NULLEMPTY);
	  if (p.error)
	    {
	      set_errno (p.error);
	      res = (unsigned long) -1;
	    }
	  else
	    res = p.binmode ();
	}
	break;
      case CW_HOOK:
	{
	  const char *name = va_arg (arg, const char *);
	  const void *hookfn = va_arg (arg, const void *);
	  WORD subsys;
	  res = (uintptr_t) hook_or_detect_cygwin (name, hookfn, subsys);
	}
	break;
      case CW_ARGV:
	{
	  child_info_spawn *ci = (child_info_spawn *) get_cygwin_startup_info ();
	  res = (uintptr_t) (ci ? ci->moreinfo->argv : NULL);
	}
	break;
      case CW_ENVP:
	{
	  child_info_spawn *ci = (child_info_spawn *) get_cygwin_startup_info ();
	  res = (uintptr_t) (ci ? ci->moreinfo->envp : NULL);
	}
	break;
      case CW_DEBUG_SELF:
	error_start_init (va_arg (arg, const char *));
	res = try_to_debug ();
	break;
      case CW_SYNC_WINENV:
	create_winenv (NULL);
	res = 0;
	break;
      case CW_CYGTLS_PADSIZE:
	res = CYGTLS_PADSIZE;
	break;
      case CW_SET_DOS_FILE_WARNING:
	{
	  dos_file_warning = va_arg (arg, int);
	  res = 0;
	}
	break;
      case CW_SET_PRIV_KEY:
	{
	  const char *passwd = va_arg (arg, const char *);
	  const char *username = va_arg (arg, const char *);
	  res = setlsapwd (passwd, username);
	}
	break;
      case CW_SETERRNO:
	{
	  const char *file = va_arg (arg, const char *);
	  int line = va_arg (arg, int);
	  seterrno(file, line);
	  res = 0;
	}
	break;
      case CW_EXIT_PROCESS:
	{
	  UINT status = va_arg (arg, UINT);
	  int useTerminateProcess = va_arg (arg, int);
	  exit_process (status, !!useTerminateProcess); /* no return */
	}
      case CW_SET_EXTERNAL_TOKEN:
	{
	  HANDLE token = va_arg (arg, HANDLE);
	  int type = va_arg (arg, int);
	  set_imp_token (token, type);
	  res = 0;
	}
	break;
      case CW_GET_INSTKEY:
	{
	  PWCHAR dest = va_arg (arg, PWCHAR);
	  wcscpy (dest, cygheap->installation_key_buf);
	  res = 0;
	}
	break;
      case CW_INT_SETLOCALE:
	{
	  extern void internal_setlocale ();
	  internal_setlocale ();
	  res = 0;
	}
	break;
      case CW_CVT_MNT_OPTS:
	{
	  extern bool fstab_read_flags (char **, unsigned &, bool);
	  char **option_string = va_arg (arg, char **);
	  if (!option_string || !*option_string)
	    set_errno (EINVAL);
	  else
	    {
	      unsigned *pflags = va_arg (arg, unsigned *);
	      unsigned flags = pflags ? *pflags : 0;
	      if (fstab_read_flags (option_string, flags, true))
		{
		  if (pflags)
		    *pflags = flags;
		  res = 0;
		}
	    }
	}
	break;
      case CW_LST_MNT_OPTS:
	{
	  extern char *fstab_list_flags ();
	  char **option_string = va_arg (arg, char **);
	  if (!option_string)
	    set_errno (EINVAL);
	  else
	    {
	      *option_string = fstab_list_flags ();
	      if (*option_string)
		res = 0;
	    }
	}
	break;
      case CW_STRERROR:
	{
	  int err = va_arg (arg, int);
	  res = (uintptr_t) strerror (err);
	}
	break;

      case CW_CVT_ENV_TO_WINENV:
	{
	  char **posix_env = va_arg (arg, char **);
	  res = (uintptr_t) create_winenv (posix_env);
	}
	break;

      case CW_ALLOC_DRIVE_MAP:
      	{
	  dos_drive_mappings *ddm = new dos_drive_mappings ();
	  res = (uintptr_t) ddm;
	}
	break;

      case CW_MAP_DRIVE_MAP:
	{
	  dos_drive_mappings *ddm = va_arg (arg, dos_drive_mappings *);
	  wchar_t *pathbuf = va_arg (arg, wchar_t *);
	  if (ddm && pathbuf)
	    res = (uintptr_t) ddm->fixup_if_match (pathbuf);
	}
	break;

      case CW_FREE_DRIVE_MAP:
	{
	  dos_drive_mappings *ddm = va_arg (arg, dos_drive_mappings *);
	  if (ddm)
	    delete ddm;
	  res = 0;
	}
	break;

      case CW_CALLOUT:
	callout = va_arg (arg, cw_callout_function_t);
	break;

      case CW_CYGHEAP_MALLOC:
	res = (uintptr_t) cmalloc (HEAP_USER, va_arg (arg, size_t));
	break;

      default:
	set_errno (ENOSYS);
    }
  va_end (arg);
  return res;
}

extern "C" void
dll_preload (const char *dll)
{
  if (!LoadLibrary (dll))
    api_fatal ("couldn't load CYGWIN=preload DLL: %s, %E", dll);
}

extern "C" cw_callout_return_t
dummy_callout (cw_callout_t, ...)
{
  return CO_R_KEEP_GOING;
}