lib/daemon.h

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef DAEMON_H
  18 #define DAEMON_H 1
  19
  20 #include <limits.h>
  21 #include <stdbool.h>
  22 #include <sys/types.h>
  23
  24 /* This file provides an interface for utilities to run in the background
  25  * as daemons on POSIX platforms like Linux or as services on Windows platform.
  26  * Some of the functionalities defined in this file are only applicable to
  27  * POSIX platforms and some are applicable only on Windows. As such, the
  28  * function definitions unique to each platform are separated out with
  29  * ifdef macros. More descriptive comments on individual functions are provided
  30  * in daemon-unix.c (for POSIX platforms) and daemon-windows.c (for Windows).
  31
  32  * The DAEMON_OPTION_ENUMS, DAEMON_LONG_OPTIONS and DAEMON_OPTION_HANDLERS
  33  * macros are useful for parsing command-line options in individual utilities.
  34  * For e.g., the command-line option "--monitor" is recognized on Linux
  35  * and results in calling the daemon_set_monitor() function. The same option is
  36  * not recognized on Windows platform.
  37  */
  38
  39 #ifndef _WIN32
  40 #define DAEMON_OPTION_ENUMS                     \
  41     OPT_DETACH,                                 \
  42     OPT_NO_CHDIR,                               \
  43     OPT_OVERWRITE_PIDFILE,                      \
  44     OPT_PIDFILE,                                \
  45     OPT_MONITOR
  46
  47 #define DAEMON_LONG_OPTIONS                                             \
  48         {"detach",            no_argument, NULL, OPT_DETACH},           \
  49         {"no-chdir",          no_argument, NULL, OPT_NO_CHDIR},         \
  50         {"pidfile",           optional_argument, NULL, OPT_PIDFILE},    \
  51         {"overwrite-pidfile", no_argument, NULL, OPT_OVERWRITE_PIDFILE}, \
  52         {"monitor",           no_argument, NULL, OPT_MONITOR}
  53
  54 #define DAEMON_OPTION_HANDLERS                  \
  55         case OPT_DETACH:                        \
  56             set_detach();                       \
  57             break;                              \
  58                                                 \
  59         case OPT_NO_CHDIR:                      \
  60             set_no_chdir();                     \
  61             break;                              \
  62                                                 \
  63         case OPT_PIDFILE:                       \
  64             set_pidfile(optarg);                \
  65             break;                              \
  66                                                 \
  67         case OPT_OVERWRITE_PIDFILE:             \
  68             ignore_existing_pidfile();          \
  69             break;                              \
  70                                                 \
  71         case OPT_MONITOR:                       \
  72             daemon_set_monitor();               \
  73             break;
  74
  75 void set_detach(void);
  76 void daemon_set_monitor(void);
  77 void set_no_chdir(void);
  78 void ignore_existing_pidfile(void);
  79 pid_t read_pidfile(const char *name);
  80 #else
  81 #define DAEMON_OPTION_ENUMS                    \
  82     OPT_DETACH,                                \
  83     OPT_NO_CHDIR,                              \
  84     OPT_PIDFILE,                               \
  85     OPT_PIPE_HANDLE,                           \
  86     OPT_SERVICE,                               \
  87     OPT_SERVICE_MONITOR
  88
  89 #define DAEMON_LONG_OPTIONS                                               \
  90         {"detach",             no_argument, NULL, OPT_DETACH},            \
  91         {"no-chdir",           no_argument, NULL, OPT_NO_CHDIR},          \
  92         {"pidfile",            optional_argument, NULL, OPT_PIDFILE},     \
  93         {"pipe-handle",        required_argument, NULL, OPT_PIPE_HANDLE}, \
  94         {"service",            no_argument, NULL, OPT_SERVICE},           \
  95         {"service-monitor",    no_argument, NULL, OPT_SERVICE_MONITOR}
  96
  97 #define DAEMON_OPTION_HANDLERS                  \
  98         case OPT_DETACH:                        \
  99             break;                              \
 100                                                 \
 101         case OPT_NO_CHDIR:                      \
 102             break;                              \
 103                                                 \
 104         case OPT_PIDFILE:                       \
 105             set_pidfile(optarg);                \
 106             break;                              \
 107                                                 \
 108         case OPT_PIPE_HANDLE:                   \
 109             set_pipe_handle(optarg);            \
 110             break;                              \
 111                                                 \
 112         case OPT_SERVICE:                       \
 113             break;                              \
 114                                                 \
 115         case OPT_SERVICE_MONITOR:               \
 116             break;
 117
 118 void control_handler(DWORD request);
 119 void set_pipe_handle(const char *pipe_handle);
 120 #endif /* _WIN32 */
 121
 122 bool get_detach(void);
 123 void daemon_save_fd(int fd);
 124 void daemonize(void);
 125 void daemonize_start(void);
 126 void daemonize_complete(void);
 127 void daemon_usage(void);
 128 void service_start(int *argcp, char **argvp[]);
 129 void service_stop(void);
 130 bool should_service_stop(void);
 131 void set_pidfile(const char *name);
 132 void close_standard_fds(void);
 133
 134 #endif /* daemon.h */