NetBSD/usr.bin/mail/sig.c

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/* $NetBSD: sig.c,v 1.3 2012/06/12 19:03:26 christos Exp $ */
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
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/*
* Copyright (c) 1980, 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.
* 3. 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: sig.c,v 1.3 2012/06/12 19:03:26 christos Exp $");
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
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#endif /* not lint */
#include <assert.h>
#include <util.h>
#include <sys/queue.h>
#include "rcv.h"
#include "extern.h"
#include "sig.h"
/*
* Mail -- a mail program
*
* Signal routines.
*/
static sig_t sigarray[NSIG];
typedef struct q_entry_s {
int qe_signo;
sig_t qe_handler;
struct q_entry_s *qe_next;
} q_entry_t;
static struct {
q_entry_t *qe_first;
q_entry_t **qe_last;
} sigq = { NULL, &sigq.qe_first };
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
2009-04-10 17:08:24 +04:00
#define SIGQUEUE_INIT(p) do {\
(p)->qe_first = NULL;\
(p)->qe_last = &((p)->qe_first);\
} while (/*CONSTCOND*/ 0)
/*
* The routines alloc_entry() and free_entry() manage the queue
* elements.
*
* Currently, they just assign one element per signo from a fix array
* as we don't support POSIX signal queues. We leave them as this may
* change in the future and the modifications will be isolated.
*/
static q_entry_t *
alloc_entry(int signo)
{
static q_entry_t entries[NSIG];
q_entry_t *e;
/*
* We currently only post one signal per signal number, so
* there is no need to make this complicated.
*/
e = &entries[signo];
if (e->qe_signo != 0)
return NULL;
e->qe_signo = signo;
e->qe_handler = sigarray[signo];
e->qe_next = NULL;
return e;
}
static void
free_entry(q_entry_t *e)
{
e->qe_signo = 0;
e->qe_handler = NULL;
e->qe_next = NULL;
}
/*
* Attempt to post a signal to the sigq.
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
2009-04-10 17:08:24 +04:00
*/
static void
sig_post(int signo)
{
q_entry_t *e;
if (sigarray[signo] == SIG_DFL || sigarray[signo] == SIG_IGN)
return;
e = alloc_entry(signo);
if (e != NULL) {
*sigq.qe_last = e;
sigq.qe_last = &e->qe_next;
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
2009-04-10 17:08:24 +04:00
}
}
/*
* Check the sigq for any pending signals. If any are found,
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
2009-04-10 17:08:24 +04:00
* preform the required actions and remove them from the queue.
*/
PUBLIC void
sig_check(void)
{
q_entry_t *e;
sigset_t nset;
sigset_t oset;
void (*handler)(int);
int signo;
(void)sigfillset(&nset);
(void)sigprocmask(SIG_SETMASK, &nset, &oset);
while ((e = sigq.qe_first) != NULL) {
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
2009-04-10 17:08:24 +04:00
signo = e->qe_signo;
handler = e->qe_handler;
/*
* Remove the entry from the queue and free it.
*/
sigq.qe_first = e->qe_next;
if (sigq.qe_first == NULL)
sigq.qe_last = &sigq.qe_first;
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
2009-04-10 17:08:24 +04:00
free_entry(e);
if (handler == SIG_DFL || handler == SIG_IGN) {
assert(/*CONSTCOND*/ 0); /* These should not get posted. */
}
else {
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
handler(signo);
(void)sigprocmask(SIG_SETMASK, &nset, NULL);
}
}
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
}
PUBLIC sig_t
sig_current(int signo)
{
assert(signo > 0 && signo < NSIG);
return sigarray[signo];
}
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
2009-04-10 17:08:24 +04:00
PUBLIC sig_t
sig_signal(int signo, sig_t handler)
{
sig_t old_handler;
sigset_t nset;
sigset_t oset;
assert(signo > 0 && signo < NSIG);
(void)sigemptyset(&nset);
(void)sigaddset(&nset, signo);
(void)sigprocmask(SIG_BLOCK, &nset, &oset);
old_handler = sigarray[signo];
sigarray[signo] = handler;
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
return old_handler;
}
static void
do_default_handler(int signo, int flags)
{
struct sigaction nsa;
struct sigaction osa;
sigset_t nset;
sigset_t oset;
int save_errno;
save_errno = errno;
(void)sigemptyset(&nsa.sa_mask);
nsa.sa_flags = flags;
nsa.sa_handler = SIG_DFL;
(void)sigaction(signo, &nsa, &osa);
(void)sigemptyset(&nset);
(void)sigaddset(&nset, signo);
(void)sigprocmask(SIG_UNBLOCK, &nset, &oset);
(void)kill(0, signo);
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
(void)sigaction(signo, &osa, NULL);
errno = save_errno;
}
/*
* Our generic signal handler.
*/
static void
sig_handler(int signo)
{
sigset_t nset;
sigset_t oset;
(void)sigfillset(&nset);
(void)sigprocmask(SIG_SETMASK, &nset, &oset);
assert (signo > 0 && signo < NSIG); /* Should be guaranteed. */
sig_post(signo);
switch (signo) {
case SIGCONT:
assert(/*CONSTCOND*/ 0); /* We should not be seeing these. */
do_default_handler(signo, 0);
break;
case SIGTSTP:
case SIGTTIN:
case SIGTTOU:
do_default_handler(signo, 0);
break;
case SIGINT:
case SIGHUP:
case SIGQUIT:
case SIGPIPE:
default:
if (sigarray[signo] == SIG_DFL)
do_default_handler(signo, SA_RESTART);
break;
}
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
}
/*
* Setup the signal handlers.
*/
PUBLIC void
sig_setup(void)
{
sigset_t nset;
sigset_t oset;
struct sigaction sa;
struct sigaction osa;
/* Block all signals while setting things. */
(void)sigfillset(&nset);
(void)sigprocmask(SIG_BLOCK, &nset, &oset);
/*
* Flow Control - SIGTSTP, SIGTTIN, SIGTTOU, SIGCONT:
*
* We grab SIGTSTP, SIGTTIN, and SIGTTOU so that we post the
* signals before suspending so that they are available when
* we resume. If we were to use SIGCONT instead, they will
* not get posted until SIGCONT is unblocked, even though the
* process has resumed.
*
* NOTE: We default these to SA_RESTART here, but we need to
* change this in certain cases, e.g., when reading from a
* tty.
*/
(void)sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
sa.sa_handler = sig_handler;
(void)sigaction(SIGTSTP, &sa, NULL);
(void)sigaction(SIGTTIN, &sa, NULL);
(void)sigaction(SIGTTOU, &sa, NULL);
/*
* SIGHUP, SIGINT, and SIGQUIT:
*
* SIGHUP and SIGINT are trapped unless they are being
* ignored.
*
* Currently, we let the default handler deal with SIGQUIT.
*/
(void)sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = sig_handler;
if (sigaction(SIGHUP, &sa, &osa) != -1 && osa.sa_handler == SIG_IGN)
(void)signal(SIGHUP, SIG_IGN);
if (sigaction(SIGINT, &sa, &osa) != -1 && osa.sa_handler == SIG_IGN)
(void)signal(SIGINT, SIG_IGN);
#if 0
if (signal(SIGQUIT, SIG_DFL) == SIG_IGN)
(void)signal(SIGQUIT, SIG_IGN);
#endif
/*
* SIGCHLD and SIGPIPE:
*
* SIGCHLD is setup early in main. The handler lives in
* popen.c as it uses internals of that module.
*
* SIGPIPE is grabbed here. It is only used in
* lex.c:setup_piping(), cmd1.c:type1(), and cmd1.c:pipecmd().
*/
(void)sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = sig_handler;
(void)sigaction(SIGPIPE, &sa, NULL);
/*
* Make sure our structures are initialized.
* XXX: This should be unnecessary.
*/
(void)memset(sigarray, 0, sizeof(sigarray));
SIGQUEUE_INIT(&sigq);
From Anon Ymous: - Remove all longjmp(3) calls from signal handlers. Instead, we post to an internal signal queue and check that periodically. All signal related code is now in sig.c, except for the SIGCHLD handler which remains in popen.c as it is intimately tied to routines there. - Handle SIGPIPE in type1() regardless of mime support, or else the handler in execute() will prevent our error code from being returned resulting in 'sawcom' not being set on the first command as it should. This only affected the initial behavior of the "next" command without mime support. - Add the 'T' flag to many commands in cmdtab.c that should not look like the first command. E.g., start mail on a mailbox with multiple messages, run "set foo", then "next", and watch the second message get displayed rather than the first as is the case without the first "set" command. - Add file descriptor and file handle leak detection. Enabled by DEBUG_FILE_LEAK. This will likely disappear in the future. - Fix a long standing (since import in 1993) longjmp() bug in edstop(): the jmpbuf was invalid when quit() is called at the end of main. - Fix a long standing bug (since import in 1993) in snarf() where it didn't strip whitespace correctly if the line consisted only of whitespace. - Lint cleanup. - New Feature: "Header" command. This allows miscellaneous header fields to be added to the header, e.g., "X-Organization:" or "Reply-To:" fields. - New Feature: "page-also" variable. This allows the specification of additional commands to page. It is more flexible than "crt". - Document the "pager-off" variable: if set, it disables paging entirely.
2009-04-10 17:08:24 +04:00
/* Restore the signal mask. */
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
}
static struct { /* data shared by sig_hold() and sig_release() */
int depth; /* depth of sig_hold() */
sigset_t oset; /* old signal mask saved by sig_hold() */
} hold;
/*
* Hold signals SIGHUP, SIGINT, and SIGQUIT.
*/
PUBLIC void
sig_hold(void)
{
sigset_t nset;
if (hold.depth++ == 0) {
(void)sigemptyset(&nset);
(void)sigaddset(&nset, SIGHUP);
(void)sigaddset(&nset, SIGINT);
(void)sigaddset(&nset, SIGQUIT);
(void)sigprocmask(SIG_BLOCK, &nset, &hold.oset);
}
}
/*
* Release signals SIGHUP, SIGINT, and SIGQUIT.
*/
PUBLIC void
sig_release(void)
{
if (--hold.depth == 0)
(void)sigprocmask(SIG_SETMASK, &hold.oset, NULL);
}
/*
* Unblock and ignore a signal.
*/
PUBLIC int
sig_ignore(int sig, struct sigaction *osa, sigset_t *oset)
{
struct sigaction act;
sigset_t nset;
int error;
(void)sigemptyset(&act.sa_mask);
act.sa_flags = SA_RESTART;
act.sa_handler = SIG_IGN;
error = sigaction(sig, &act, osa);
if (error != -1) {
(void)sigemptyset(&nset);
(void)sigaddset(&nset, sig);
(void)sigprocmask(SIG_UNBLOCK, &nset, oset);
} else if (oset != NULL)
(void)sigprocmask(SIG_UNBLOCK, NULL, oset);
return error;
}
/*
* Restore a signal and the current signal mask.
*/
PUBLIC int
sig_restore(int sig, struct sigaction *osa, sigset_t *oset)
{
int error;
error = 0;
if (oset)
error = sigprocmask(SIG_SETMASK, oset, NULL);
if (osa)
error = sigaction(sig, osa, NULL);
return error;
}
/*
* Change the current flags and (optionally) return the old sigaction
* structure so we can restore things later. This is used to turn
* SA_RESTART on or off.
*/
PUBLIC int
sig_setflags(int signo, int flags, struct sigaction *osa)
{
struct sigaction sa;
if (sigaction(signo, NULL, &sa) == -1)
return -1;
if (osa)
*osa = sa;
sa.sa_flags = flags;
return sigaction(signo, &sa, NULL);
}