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_SELF_CONFINEMENT,                    \
  43     OPT_NO_CHDIR,                               \
  44     OPT_OVERWRITE_PIDFILE,                      \
  45     OPT_PIDFILE,                                \
  46     OPT_MONITOR,                                \
  47     OPT_USER_GROUP
  48
  49 #define DAEMON_LONG_OPTIONS                                              \
  50         {"detach",            no_argument, NULL, OPT_DETACH},            \
  51         {"no-self-confinement", no_argument, NULL, OPT_NO_SELF_CONFINEMENT}, \
  52         {"no-chdir",          no_argument, NULL, OPT_NO_CHDIR},          \
  53         {"pidfile",           optional_argument, NULL, OPT_PIDFILE},     \
  54         {"overwrite-pidfile", no_argument, NULL, OPT_OVERWRITE_PIDFILE}, \
  55         {"monitor",           no_argument, NULL, OPT_MONITOR},           \
  56         {"user",              required_argument, NULL, OPT_USER_GROUP}
  57
  58 #define DAEMON_OPTION_HANDLERS                  \
  59         case OPT_DETACH:                        \
  60             set_detach();                       \
  61             break;                              \
  62                                                 \
  63         case OPT_NO_SELF_CONFINEMENT:           \
  64             daemon_disable_self_confinement();  \
  65             break;                              \
  66                                                 \
  67         case OPT_NO_CHDIR:                      \
  68             set_no_chdir();                     \
  69             break;                              \
  70                                                 \
  71         case OPT_PIDFILE:                       \
  72             set_pidfile(optarg);                \
  73             break;                              \
  74                                                 \
  75         case OPT_OVERWRITE_PIDFILE:             \
  76             ignore_existing_pidfile();          \
  77             break;                              \
  78                                                 \
  79         case OPT_MONITOR:                       \
  80             daemon_set_monitor();               \
  81             break;                              \
  82                                                 \
  83         case OPT_USER_GROUP:                    \
  84             daemon_set_new_user(optarg);        \
  85             break;
  86
  87 void set_detach(void);
  88 void daemon_set_monitor(void);
  89 void set_no_chdir(void);
  90 void ignore_existing_pidfile(void);
  91 pid_t read_pidfile(const char *name);
  92 #else
  93 #define DAEMON_OPTION_ENUMS                    \
  94     OPT_DETACH,                                \
  95     OPT_NO_SELF_CONFINEMENT,                   \
  96     OPT_NO_CHDIR,                              \
  97     OPT_PIDFILE,                               \
  98     OPT_PIPE_HANDLE,                           \
  99     OPT_SERVICE,                               \
 100     OPT_SERVICE_MONITOR,                       \
 101     OPT_USER_GROUP
 102
 103 #define DAEMON_LONG_OPTIONS                                               \
 104         {"detach",             no_argument, NULL, OPT_DETACH},            \
 105         {"no-self-confinement", no_argument, NULL, OPT_NO_SELF_CONFINEMENT}, \
 106         {"no-chdir",           no_argument, NULL, OPT_NO_CHDIR},          \
 107         {"pidfile",            optional_argument, NULL, OPT_PIDFILE},     \
 108         {"pipe-handle",        required_argument, NULL, OPT_PIPE_HANDLE}, \
 109         {"service",            no_argument, NULL, OPT_SERVICE},           \
 110         {"service-monitor",    no_argument, NULL, OPT_SERVICE_MONITOR},   \
 111         {"user",               required_argument, NULL, OPT_USER_GROUP}
 112
 113 #define DAEMON_OPTION_HANDLERS                  \
 114         case OPT_DETACH:                        \
 115             break;                              \
 116                                                 \
 117         case OPT_NO_SELF_CONFINEMENT:           \
 118             daemon_disable_self_confinement();  \
 119             break;                              \
 120                                                 \
 121         case OPT_NO_CHDIR:                      \
 122             break;                              \
 123                                                 \
 124         case OPT_PIDFILE:                       \
 125             set_pidfile(optarg);                \
 126             break;                              \
 127                                                 \
 128         case OPT_PIPE_HANDLE:                   \
 129             set_pipe_handle(optarg);            \
 130             break;                              \
 131                                                 \
 132         case OPT_SERVICE:                       \
 133             break;                              \
 134                                                 \
 135         case OPT_SERVICE_MONITOR:               \
 136             break;                              \
 137                                                 \
 138         case OPT_USER_GROUP:                    \
 139             daemon_set_new_user(optarg);
 140
 141 void control_handler(DWORD request);
 142 void set_pipe_handle(const char *pipe_handle);
 143 #endif /* _WIN32 */
 144
 145 bool get_detach(void);
 146 void daemon_save_fd(int fd);
 147 void daemonize(void);
 148 void daemonize_start(bool access_datapath);
 149 void daemonize_complete(void);
 150 void daemon_set_new_user(const char * user_spec);
 151 void daemon_become_new_user(bool access_datapath);
 152 void daemon_usage(void);
 153 void daemon_disable_self_confinement(void);
 154 bool daemon_should_self_confine(void);
 155 void service_start(int *argcp, char **argvp[]);
 156 void service_stop(void);
 157 bool should_service_stop(void);
 158 void set_pidfile(const char *name);
 159 void close_standard_fds(void);
 160
 161 #endif /* daemon.h */