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