/*

 * SPDX-License-Identifier: ISC

 *

 * Copyright (c) 1999-2005, 2007, 2009-2015

 *  Todd C. Miller <Todd.Miller@sudo.ws>

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 *

 * Sponsored in part by the Defense Advanced Research Projects

 * Agency (DARPA) and Air Force Research Laboratory, Air Force

 * Materiel Command, USAF, under agreement number F39502-99-1-0512.

 */

#include <config.h>

#include <stdlib.h>

#include <string.h>

#ifdef HAVE_STDBOOL_H

# include <stdbool.h>

#else

# include <compat/stdbool.h>

#endif

#include <errno.h>

#include <fcntl.h>

#include <unistd.h>

#include <sudo_compat.h>

#include <sudo_util.h>

#include <sudo_debug.h>

bool

sudo_lock_file_v1(int fd, int type)

{

    return sudo_lock_region_v1(fd, type, 0);

}

/*

 * Lock/unlock all or part of a file.

 */

#ifdef HAVE_LOCKF

bool

sudo_lock_region_v1(int fd, int type, off_t len)

{

    int op, rc;

    off_t oldpos = -1;

    debug_decl(sudo_lock_region, SUDO_DEBUG_UTIL);

    switch (type) {

  case SUDO_LOCK:

      sudo_debug_printf(SUDO_DEBUG_INFO, "%s: lock %d:%lld",

    __func__, fd, (long long)len);

      op = F_LOCK;

      break;

  case SUDO_TLOCK:

      sudo_debug_printf(SUDO_DEBUG_INFO, "%s: tlock %d:%lld",

    __func__, fd, (long long)len);

      op = F_TLOCK;

      break;

  case SUDO_UNLOCK:

      sudo_debug_printf(SUDO_DEBUG_INFO, "%s: unlock %d:%lld",

    __func__, fd, (long long)len);

      op = F_ULOCK;

      /* Must seek to start of file to unlock the entire thing. */

      if (len == 0 && (oldpos = lseek(fd, 0, SEEK_CUR)) != -1) {

    if (lseek(fd, 0, SEEK_SET) == -1) {

        sudo_debug_printf(

      SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,

      "unable to seek to beginning");

    }

      }

      break;

  default:

      sudo_debug_printf(SUDO_DEBUG_INFO, "%s: bad lock type %d",

    __func__, type);

      errno = EINVAL;

      debug_return_bool(false);

    }

    rc = lockf(fd, op, len);

    if (oldpos != -1) {

  if (lseek(fd, oldpos, SEEK_SET) == -1) {

      sudo_debug_printf(

    SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO,

    "unable to restore offset");

  }

    }

    debug_return_bool(rc == 0);

}

#else

bool

sudo_lock_region_v1(int fd, int type, off_t len)

{

    struct flock lock;

    int func;

    debug_decl(sudo_lock_file, SUDO_DEBUG_UTIL);

    switch (type) {

  case SUDO_LOCK:

      sudo_debug_printf(SUDO_DEBUG_INFO, "%s: lock %d:%lld",

    __func__, fd, (long long)len);

      lock.l_type = F_WRLCK;

      func = F_SETLKW;

      break;

  case SUDO_TLOCK:

      sudo_debug_printf(SUDO_DEBUG_INFO, "%s: tlock %d:%lld",

    __func__, fd, (long long)len);

      lock.l_type = F_WRLCK;

      func = F_SETLK;

      break;

  case SUDO_UNLOCK:

      sudo_debug_printf(SUDO_DEBUG_INFO, "%s: unlock %d:%lld",

    __func__, fd, (long long)len);

      lock.l_type = F_UNLCK;

      func = F_SETLK;

      break;

  default:

      sudo_debug_printf(SUDO_DEBUG_INFO, "%s: bad lock type %d",

    __func__, type);

      errno = EINVAL;

      debug_return_bool(false);

    }

    lock.l_start = 0;

    lock.l_len = len;

    lock.l_pid = 0;

    lock.l_whence = len ? SEEK_CUR : SEEK_SET;

    debug_return_bool(fcntl(fd, func, &lock) == 0);

}

#endif