=encoding utf-8


=head1 Name

lua-resty-signal - Lua library for killing or sending signals to Linux processes


=head1 Synopsis


    local resty_signal = require "resty.signal"
    local pid = 12345
    
    local ok, err = resty_signal.kill(pid, "TERM")
    if not ok then
        ngx.log(ngx.ERR, "failed to kill process of pid ", pid, ": ", err)
        return
    end
    
    -- send the signal 0 to check the existence of a process
    local ok, err = resty_signal.kill(pid, "NONE")
    
    local ok, err = resty_signal.kill(pid, "HUP")
    
    local ok, err = resty_signal.kill(pid, "KILL")


=head1 Functions


=head2 kill

B<syntax:> C<ok, err = resty_signal.kill(pid, signal_name_or_num)>

Sends a signal with its name string or number value to the process of the
specified pid.

All signal names accepted by L<signum> are supported, like C<HUP>,
C<KILL>, and C<TERM>.

Signal numbers are also supported when specifying nonportable system-specific
signals is desired.




=head2 signum

B<syntax:> C<num = resty_signal.signum(sig_name)>

Maps the signal name specified to the system-specific signal number. Returns
C<nil> if the signal name is not known.

All the POSIX and BSD signal names are supported:


    INT
    QUIT
    ILL
    TRAP
    ABRT
    BUS
    FPE
    KILL
    USR1
    SEGV
    USR2
    PIPE
    ALRM
    TERM
    CHLD
    CONT
    STOP
    TSTP
    TTIN
    TTOU
    URG
    XCPU
    XFSZ
    VTALRM
    PROF
    WINCH
    IO
    PWR
    EMT
    SYS
    INFO

The special signal name C<NONE> is also supported, which is mapped to zero (0).




=head1 Author

Yichun Zhang (agentzh) E<lt>yichun@openresty.comE<gt>




=head1 Copyright & Licenses

This module is licensed under the BSD license.

Copyright (C) 2018-2019, L<OpenResty Inc.|https://openresty.com>

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:


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=item *

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.


=back


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=item *

Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.


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Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.


=back

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


