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Diffstat (limited to 'lib/libc/compat-43/sigvec.2')
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diff --git a/lib/libc/compat-43/sigvec.2 b/lib/libc/compat-43/sigvec.2 new file mode 100644 index 0000000..d15c023 --- /dev/null +++ b/lib/libc/compat-43/sigvec.2 @@ -0,0 +1,342 @@ +.\" Copyright (c) 1980, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. 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. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. +.\" +.\" @(#)sigvec.2 8.2 (Berkeley) 4/19/94 +.\" $FreeBSD$ +.\" +.Dd April 19, 1994 +.Dt SIGVEC 2 +.Os +.Sh NAME +.Nm sigvec +.Nd software signal facilities +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In signal.h +.Bd -literal +struct sigvec { + void (*sv_handler)(); + int sv_mask; + int sv_flags; +}; +.Ed +.Ft int +.Fn sigvec "int sig" "struct sigvec *vec" "struct sigvec *ovec" +.Sh DESCRIPTION +.Bf -symbolic +This interface is made obsolete by +.Xr sigaction 2 . +.Ef +.Pp +The system defines a set of signals that may be delivered to a process. +Signal delivery resembles the occurrence of a hardware interrupt: +the signal is blocked from further occurrence, the current process +context is saved, and a new one is built. +A process may specify a +.Em handler +to which a signal is delivered, or specify that a signal is to be +.Em blocked +or +.Em ignored . +A process may also specify that a default action is to be taken +by the system when a signal occurs. +Normally, signal handlers execute on the current stack +of the process. +This may be changed, on a per-handler basis, +so that signals are taken on a special +.Em "signal stack" . +.Pp +All signals have the same +.Em priority . +Signal routines execute with the signal that caused their +invocation +.Em blocked , +but other signals may yet occur. +A global +.Em "signal mask" +defines the set of signals currently blocked from delivery +to a process. +The signal mask for a process is initialized +from that of its parent (normally 0). +It +may be changed with a +.Xr sigblock 2 +or +.Xr sigsetmask 2 +call, or when a signal is delivered to the process. +.Pp +When a signal +condition arises for a process, the signal is added to a set of +signals pending for the process. +If the signal is not currently +.Em blocked +by the process then it is delivered to the process. +When a signal +is delivered, the current state of the process is saved, +a new signal mask is calculated (as described below), +and the signal handler is invoked. +The call to the handler +is arranged so that if the signal handling routine returns +normally the process will resume execution in the context +from before the signal's delivery. +If the process wishes to resume in a different context, then it +must arrange to restore the previous context itself. +.Pp +When a signal is delivered to a process a new signal mask is +installed for the duration of the process' signal handler +(or until a +.Xr sigblock 2 +or +.Xr sigsetmask 2 +call is made). +This mask is formed by taking the current signal mask, +adding the signal to be delivered, and +.Em or Ns 'ing +in the signal mask associated with the handler to be invoked. +.Pp +The +.Fn sigvec +function +assigns a handler for a specific signal. +If +.Fa vec +is non-zero, it +specifies a handler routine and mask +to be used when delivering the specified signal. +Further, if the +.Dv SV_ONSTACK +bit is set in +.Fa sv_flags , +the system will deliver the signal to the process on a +.Em "signal stack" , +specified with +.Xr sigaltstack 2 . +If +.Fa ovec +is non-zero, the previous handling information for the signal +is returned to the user. +.Pp +The following is a list of all signals +with names as in the include file +.In signal.h : +.Bl -column SIGVTALARMXX "create core imagexxx" +.It Sy "NAME Default Action Description" +.It Dv SIGHUP No " terminate process" " terminal line hangup" +.It Dv SIGINT No " terminate process" " interrupt program" +.It Dv SIGQUIT No " create core image" " quit program" +.It Dv SIGILL No " create core image" " illegal instruction" +.It Dv SIGTRAP No " create core image" " trace trap" +.It Dv SIGABRT No " create core image" Ta Xr abort 3 +call (formerly +.Dv SIGIOT ) +.It Dv SIGEMT No " create core image" " emulate instruction executed" +.It Dv SIGFPE No " create core image" " floating-point exception" +.It Dv SIGKILL No " terminate process" " kill program" +.It Dv SIGBUS No " create core image" " bus error" +.It Dv SIGSEGV No " create core image" " segmentation violation" +.It Dv SIGSYS No " create core image" " non-existent system call invoked" +.It Dv SIGPIPE No " terminate process" " write on a pipe with no reader" +.It Dv SIGALRM No " terminate process" " real-time timer expired" +.It Dv SIGTERM No " terminate process" " software termination signal" +.It Dv SIGURG No " discard signal" " urgent condition present on socket" +.It Dv SIGSTOP No " stop process" " stop (cannot be caught or ignored)" +.It Dv SIGTSTP No " stop process" " stop signal generated from keyboard" +.It Dv SIGCONT No " discard signal" " continue after stop" +.It Dv SIGCHLD No " discard signal" " child status has changed" +.It Dv SIGTTIN No " stop process" " background read attempted from control terminal" +.It Dv SIGTTOU No " stop process" " background write attempted to control terminal" +.It Dv SIGIO No " discard signal" Tn " I/O" +is possible on a descriptor (see +.Xr fcntl 2 ) +.It Dv SIGXCPU No " terminate process" " cpu time limit exceeded (see" +.Xr setrlimit 2 ) +.It Dv SIGXFSZ No " terminate process" " file size limit exceeded (see" +.Xr setrlimit 2 ) +.It Dv SIGVTALRM No " terminate process" " virtual time alarm (see" +.Xr setitimer 2 ) +.It Dv SIGPROF No " terminate process" " profiling timer alarm (see" +.Xr setitimer 2 ) +.It Dv SIGWINCH No " discard signal" " Window size change" +.It Dv SIGINFO No " discard signal" " status request from keyboard" +.It Dv SIGUSR1 No " terminate process" " User defined signal 1" +.It Dv SIGUSR2 No " terminate process" " User defined signal 2" +.El +.Pp +Once a signal handler is installed, it remains installed +until another +.Fn sigvec +call is made, or an +.Xr execve 2 +is performed. +A signal-specific default action may be reset by +setting +.Fa sv_handler +to +.Dv SIG_DFL . +The defaults are process termination, possibly with core dump; +no action; stopping the process; or continuing the process. +See the above signal list for each signal's default action. +If +.Fa sv_handler +is +.Dv SIG_IGN +current and pending instances +of the signal are ignored and discarded. +.Pp +If a signal is caught during the system calls listed below, +the call is normally restarted. +The call can be forced to terminate prematurely with an +.Er EINTR +error return by setting the +.Dv SV_INTERRUPT +bit in +.Fa sv_flags . +The affected system calls include +.Xr read 2 , +.Xr write 2 , +.Xr sendto 2 , +.Xr recvfrom 2 , +.Xr sendmsg 2 +and +.Xr recvmsg 2 +on a communications channel or a slow device (such as a terminal, +but not a regular file) +and during a +.Xr wait 2 +or +.Xr ioctl 2 . +However, calls that have already committed are not restarted, +but instead return a partial success (for example, a short read count). +.Pp +After a +.Xr fork 2 +or +.Xr vfork 2 +all signals, the signal mask, the signal stack, +and the restart/interrupt flags are inherited by the child. +.Pp +The +.Xr execve 2 +system call reinstates the default +action for all signals which were caught and +resets all signals to be caught on the user stack. +Ignored signals remain ignored; +the signal mask remains the same; +signals that interrupt system calls continue to do so. +.Sh NOTES +The mask specified in +.Fa vec +is not allowed to block +.Dv SIGKILL +or +.Dv SIGSTOP . +This is done silently by the system. +.Pp +The +.Dv SV_INTERRUPT +flag is not available in +.Bx 4.2 , +hence it should not be used if backward compatibility is needed. +.Sh RETURN VALUES +.Rv -std sigvec +.Sh EXAMPLES +On the +.Tn VAX\-11 +The handler routine can be declared: +.Bd -literal -offset indent +void handler(sig, code, scp) +int sig, code; +struct sigcontext *scp; +.Ed +.Pp +Here +.Fa sig +is the signal number, into which the hardware faults and traps are +mapped as defined below. +The +.Fa code +argument +is either a constant +as given below or, for compatibility mode faults, the code provided by +the hardware (Compatibility mode faults are distinguished from the +other +.Dv SIGILL +traps by having +.Dv PSL_CM +set in the psl). +The +.Fa scp +argument +is a pointer to the +.Fa sigcontext +structure (defined in +.In signal.h ) , +used to restore the context from before the signal. +.Sh ERRORS +The +.Fn sigvec +function +will fail and no new signal handler will be installed if one +of the following occurs: +.Bl -tag -width Er +.It Bq Er EFAULT +Either +.Fa vec +or +.Fa ovec +points to memory that is not a valid part of the process +address space. +.It Bq Er EINVAL +The +.Fa sig +argument +is not a valid signal number. +.It Bq Er EINVAL +An attempt is made to ignore or supply a handler for +.Dv SIGKILL +or +.Dv SIGSTOP . +.El +.Sh SEE ALSO +.Xr kill 1 , +.Xr kill 2 , +.Xr ptrace 2 , +.Xr sigaction 2 , +.Xr sigaltstack 2 , +.Xr sigblock 2 , +.Xr sigpause 2 , +.Xr sigprocmask 2 , +.Xr sigsetmask 2 , +.Xr sigsuspend 2 , +.Xr setjmp 3 , +.Xr siginterrupt 3 , +.Xr signal 3 , +.Xr sigsetops 3 , +.Xr tty 4 +.Sh BUGS +This manual page is still confusing. |
