1/* 2 Copyright (c) 2009 Frank Lahm <franklahm@gmail.com> 3 4 This program is free software; you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 2 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13*/ 14 15/*! 16 * @file 17 * Netatalk utility functions 18 */ 19 20#ifdef HAVE_CONFIG_H 21#include "config.h" 22#endif /* HAVE_CONFIG_H */ 23 24#include <unistd.h> 25#include <fcntl.h> 26#include <atalk/util.h> 27 28/*! 29 * @def read_lock(fd, offset, whence, len) 30 * @brief place read lock on file 31 * 32 * @param fd (r) File descriptor 33 * @param offset (r) byte offset relative to l_whence 34 * @param whence (r) SEEK_SET, SEEK_CUR, SEEK_END 35 * @param len (r) no. of bytes (0 means to EOF) 36 * 37 * @returns 0 on success, -1 on failure with 38 * fcntl return value and errno 39 */ 40 41/*! 42 * @def write_lock(fd, offset, whence, len) 43 * @brief place write lock on file 44 * 45 * @param fd (r) File descriptor 46 * @param offset (r) byte offset relative to l_whence 47 * @param whence (r) SEEK_SET, SEEK_CUR, SEEK_END 48 * @param len (r) no. of bytes (0 means to EOF) 49 * 50 * @returns 0 on success, -1 on failure with 51 * fcntl return value and errno 52 */ 53 54/*! 55 * @def unlock(fd, offset, whence, len) 56 * @brief unlock a file 57 * 58 * @param fd (r) File descriptor 59 * @param offset (r) byte offset relative to l_whence 60 * @param whence (r) SEEK_SET, SEEK_CUR, SEEK_END 61 * @param len (r) no. of bytes (0 means to EOF) 62 * 63 * @returns 0 on success, -1 on failure with 64 * fcntl return value and errno 65 */ 66 67/*! 68 * @brief lock a file with fctnl 69 * 70 * This function is called via the macros: 71 * read_lock, write_lock, un_lock 72 * 73 * @param fd (r) File descriptor 74 * @param cmd (r) cmd to fcntl, only F_SETLK is usable here 75 * @param type (r) F_RDLCK, F_WRLCK, F_UNLCK 76 * @param offset (r) byte offset relative to l_whence 77 * @param whence (r) SEEK_SET, SEEK_CUR, SEEK_END 78 * @param len (r) no. of bytes (0 means to EOF) 79 * 80 * @returns 0 on success, -1 on failure with 81 * fcntl return value and errno 82 * 83 * @sa read_lock, write_lock, unlock 84 */ 85int lock_reg(int fd, int cmd, int type, off_t offset, int whence, off_t len) 86{ 87 struct flock lock; 88 89 lock.l_type = type; 90 lock.l_start = offset; 91 lock.l_whence = whence; 92 lock.l_len = len; 93 94 return (fcntl(fd, cmd, &lock)); 95} 96