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diff --git a/man2/kill.2 b/man2/kill.2 new file mode 100644 index 000000000..bfff57ada --- /dev/null +++ b/man2/kill.2 @@ -0,0 +1,140 @@ +.\" Hey Emacs! This file is -*- nroff -*- source. +.\" +.\" Copyright (c) 1992 Drew Eckhardt (drew@cs.colorado.edu), March 28, 1992 +.\" +.\" Permission is granted to make and distribute verbatim copies of this +.\" manual provided the copyright notice and this permission notice are +.\" preserved on all copies. +.\" +.\" Permission is granted to copy and distribute modified versions of this +.\" manual under the conditions for verbatim copying, provided that the +.\" entire resulting derived work is distributed under the terms of a +.\" permission notice identical to this one. +.\" +.\" Since the Linux kernel and libraries are constantly changing, this +.\" manual page may be incorrect or out-of-date. The author(s) assume no +.\" responsibility for errors or omissions, or for damages resulting from +.\" the use of the information contained herein. The author(s) may not +.\" have taken the same level of care in the production of this manual, +.\" which is licensed free of charge, as they might when working +.\" professionally. +.\" +.\" Formatted or processed versions of this manual, if unaccompanied by +.\" the source, must acknowledge the copyright and authors of this work. +.\" +.\" Modified by Michael Haardt <michael@moria.de> +.\" Modified by Thomas Koenig <ig25@rz.uni-karlsruhe.de> +.\" Modified 1993-07-23 by Rik Faith <faith@cs.unc.edu> +.\" Modified 1993-07-25 by Rik Faith <faith@cs.unc.edu> +.\" Modified 1995-11-01 by Michael Haardt +.\" <michael@cantor.informatik.rwth-aachen.de> +.\" Modified 1996-04-14 by Andries Brouwer <aeb@cwi.nl> +.\" [added some polishing contributed by Mike Battersby <mib@deakin.edu.au>] +.\" Modified 1996-07-21 by Andries Brouwer <aeb@cwi.nl> +.\" Modified 1997-01-17 by Andries Brouwer <aeb@cwi.nl> +.\" Modified 2001-12-18 by Andries Brouwer <aeb@cwi.nl> +.\" Modified 2002-07-24 by Michael Kerrisk <mtk16@ext.canterbury.ac.nz> +.\" Added note on historical rules enforced when an unprivileged process +.\" sends a signal. +.\" Modified 2004-06-16 by Michael Kerrisk <mtk16@ext.canterbury.ac.nz> +.\" Added note on CAP_KILL +.\" Modified 2004-06-24 by aeb +.\" +.TH KILL 2 2004-06-24 "Linux 2.6.7" "Linux Programmer's Manual" +.SH NAME +kill \- send signal to a process +.SH SYNOPSIS +.nf +.B #include <sys/types.h> +.br +.B #include <signal.h> +.sp +.BI "int kill(pid_t " pid ", int " sig ); +.fi +.SH DESCRIPTION +The +.B kill +system call +can be used to send any signal to any process group or process. +.PP +If \fIpid\fP is positive, then signal \fIsig\fP is sent to \fIpid\fP. +.PP +If \fIpid\fP equals 0, then \fIsig\fP is sent to every process in the +process group of the current process. +.PP +If \fIpid\fP equals \-1, then \fIsig\fP is sent to every process except +for process 1 (init), but see below. +.PP +If \fIpid\fP is less than \-1, then \fIsig\fP is sent to every process +in the process group \fI\-pid\fP. +.PP +If \fIsig\fP is 0, then no signal is sent, but error checking is still +performed. + +For a process to have permission to send a signal +it must either be privileged (under Linux: have the +.B CAP_KILL +capability), or the real or effective +user ID of the sending process must equal the real or +saved set-user-ID of the target process. +In the case of SIGCONT it suffices when the sending and receiving +processes belong to the same session. +.SH "RETURN VALUE" +On success (at least one signal was sent), zero is returned. +On error, \-1 is returned, and +.I errno +is set appropriately. +.SH ERRORS +.TP +.B EINVAL +An invalid signal was specified. +.TP +.B EPERM +The process does not have permission to send the signal +to any of the target processes. +.TP +.B ESRCH +The pid or process group does not exist. +Note that an existing process might be a zombie, +a process which already committed termination, but +has not yet been \fBwait()\fPed for. +.SH NOTES +It is impossible to send a signal to task number one, the init process, for +which it has not installed a signal handler. This is done to assure the +system is not brought down accidentally. +.LP +POSIX 1003.1-2001 requires that \fIkill(-1,sig)\fP send \fIsig\fP +to all processes that the current process may send signals to, +except possibly for some implementation-defined system processes. +Linux allows a process to signal itself, but on Linux the call +\fIkill(-1,sig)\fP does not signal the current process. +.LP +POSIX 1003.1-2003 requires that if a process sends a signal to itself, +and that process does not have the signal blocked, and no other thread +has it unblocked or is waiting for it in \fIsigwait()\fP, at least one +unblocked signal must be delivered to the sending thread before the +call of \fIkill()\fP returns. +.SH "LINUX HISTORY" +Across different kernel versions, Linux has enforced different rules +for the permissions required for an unprivileged process +to send a signal to another process. +.\" In the 0.* kernels things chopped and changed quite +.\" a bit - MTK, 24 Jul 02 +In kernels 1.0 to 1.2.2, a signal could be sent if the +effective user ID of the sender matched that of the receiver, +or the real user ID of the sender matched that of the receiver. +From kernel 1.2.3 until 1.3.77, a signal could be sent if the +effective user ID of the sender matched either the real or effective +user ID of the receiver. +The current rules, which conform to POSIX 1003.1-2001, were adopted +in kernel 1.3.78. +.SH "CONFORMING TO" +SVr4, SVID, POSIX.1, X/OPEN, BSD 4.3, POSIX 1003.1-2001 +.SH "SEE ALSO" +.BR _exit (2), +.BR killpg (2), +.BR signal (2), +.BR tkill (2), +.BR exit (3), +.BR capabilities (7), +.BR signal (7) |