dfork.h(3) libdaemon dfork.h(3)
NAME
dfork.h - Contains an API for doing a daemonizing fork().
SYNOPSIS
#include <sys/types.h>
Macros
#define DAEMON_CLOSE_ALL_AVAILABLE 1
This variable is defined to 1 iff daemon_close_all() and
daemon_close_allv() are supported.
#define DAEMON_UNBLOCK_SIGS_AVAILABLE 1
This variable is defined to 1 iff daemon_unblock_sigs() and
daemon_unblock_sigsv() are supported.
#define DAEMON_RESET_SIGS_AVAILABLE 1
This variable is defined to 1 iff daemon_reset_sigs() and
daemon_reset_sigsv() are supported.
Functions
pid_t daemon_fork (void)
Does a daemonizing fork().
int daemon_retval_init (void)
Allocate and initialize resources required by the
daemon_retval_xxx() functions.
void daemon_retval_done (void)
Frees the resources allocated by daemon_retval_init().
int daemon_retval_wait (int timeout)
Return the value sent by the child via the daemon_retval_send()
function, but wait only the specified number of seconds before
timing out and returning a negative number.
int daemon_retval_send (int s)
Send the specified integer to the parent process.
int daemon_close_all (int except_fd,...)
Close all file descriptors except those passed.
int daemon_close_allv (const int except_fds[])
Same as daemon_close_all but takes an array of fds, terminated by
-1.
int daemon_unblock_sigs (int except,...)
Unblock all signals except those passed.
int daemon_unblock_sigsv (const int except[])
Same as daemon_unblock_sigs() but takes an array of signals,
terminated by -1.
int daemon_reset_sigs (int except,...)
Reset all signal handlers except those passed.
int daemon_reset_sigsv (const int except[])
Same as daemon_reset_sigs() but takes an array of signals,
terminated by -1.
Detailed Description
Contains an API for doing a daemonizing fork().
You may daemonize by calling daemon_fork(), a function similar to the
plain fork(). If you want to return a return value of the initialization
procedure of the child from the parent, you may use the
daemon_retval_xxx() functions.
Definition in file dfork.h.
Macro Definition Documentation
#define DAEMON_CLOSE_ALL_AVAILABLE 1
This variable is defined to 1 iff daemon_close_all() and
daemon_close_allv() are supported.
Since
0.11
See also
daemon_close_all(), daemon_close_allv()
Definition at line 106 of file dfork.h.
#define DAEMON_RESET_SIGS_AVAILABLE 1
This variable is defined to 1 iff daemon_reset_sigs() and
daemon_reset_sigsv() are supported.
Since
0.13
See also
daemon_reset_sigs(), daemon_reset_sigsv()
Definition at line 142 of file dfork.h.
#define DAEMON_UNBLOCK_SIGS_AVAILABLE 1
This variable is defined to 1 iff daemon_unblock_sigs() and
daemon_unblock_sigsv() are supported.
Since
0.13
See also
daemon_unblock_sigs(), daemon_unblock_sigsv()
Definition at line 124 of file dfork.h.
Function Documentation
int daemon_close_all (int except_fd, ...)
Close all file descriptors except those passed. List needs to be
terminated by -1. FDs 0, 1, 2 will be kept open anyway.
Since
0.11
See also
DAEMON_CLOSE_ALL_AVAILABLE
Examples
testd.c.
int daemon_close_allv (const int except_fds[])
Same as daemon_close_all but takes an array of fds, terminated by -1.
Since
0.11
See also
DAEMON_CLOSE_ALL_AVAILABLE
pid_t daemon_fork (void)
Does a daemonizing fork(). For the new daemon process STDIN, STDOUT,
STDERR are connected to /dev/null, the process is a session leader, the
current directory is changed to /, the umask is set to 777.
Returns
On success, the PID of the child process is returned in the parent's
thread of execution, and a 0 is returned in the child's thread of
execution. On failure, -1 will be returned in the parent's context,
no child process will be created, and errno will be set
appropriately.
Examples
testd.c.
int daemon_reset_sigs (int except, ...)
Reset all signal handlers except those passed. List needs to be
terminated by -1.
Since
0.13
See also
DAEMON_RESET_SIGS_AVAILABLE
Examples
testd.c.
int daemon_reset_sigsv (const int except[])
Same as daemon_reset_sigs() but takes an array of signals, terminated by
-1.
Since
0.13
See also
DAEMON_RESET_SIGS_AVAILABLE
void daemon_retval_done (void)
Frees the resources allocated by daemon_retval_init(). This should be
called if neither daemon_retval_wait() nor daemon_retval_send() is
called in the current process. The resources allocated by
daemon_retval_init() should be freed in both parent and daemon process.
This may be achieved by using daemon_retval_wait() resp.
daemon_retval_send(), or by using daemon_retval_done().
Examples
testd.c.
int daemon_retval_init (void)
Allocate and initialize resources required by the daemon_retval_xxx()
functions. These functions allow the child to send a value to the parent
after completing its initialisation. Call this in the parent before
forking.
Returns
zero on success, nonzero on failure.
Examples
testd.c.
int daemon_retval_send (int s)
Send the specified integer to the parent process. Do not send -1 because
this signifies a library error. Should be called just once from the
daemon process only. A subsequent call to daemon_retval_done() in the
daemon is ignored.
Parameters
s The integer to pass to daemon_retval_wait() in the parent process
Returns
Zero on success, nonzero on failure.
Examples
testd.c.
int daemon_retval_wait (int timeout)
Return the value sent by the child via the daemon_retval_send()
function, but wait only the specified number of seconds before timing
out and returning a negative number. Should be called just once from the
parent process only. A subsequent call to daemon_retval_done() in the
parent is ignored.
Parameters
timeout Thetimeout in seconds
Returns
The integer passed daemon_retval_send() in the daemon process, or -1
on failure.
Examples
testd.c.
int daemon_unblock_sigs (int except, ...)
Unblock all signals except those passed. List needs to be terminated by
-1.
Since
0.13
See also
DAEMON_UNBLOCK_SIGS_AVAILABLE
Examples
testd.c.
int daemon_unblock_sigsv (const int except[])
Same as daemon_unblock_sigs() but takes an array of signals, terminated
by -1.
Since
0.13
See also
DAEMON_UNBLOCK_SIGS_AVAILABLE
Author
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