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Signals: Correct implementation of sigset(). It is not just signal() with a different name; it has some additional signal mask handling functionality

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This commit is contained in:
Gregory Nutt 2016-04-11 09:04:54 -06:00
parent fec1931def
commit 6653c5cbf3
8 changed files with 188 additions and 81 deletions
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2
README.txt
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@ -439,7 +439,7 @@ Refreshing Configurations
be? Enter ? in response to the 'make oldconfig' prompt and it will show
you the help text that goes with the option.
If you don't want to make any decisions are are willing to just accep the
If you don't want to make any decisions are are willing to just accept the
recommended default value for each new configuration item, an even easier
way is:

38
include/signal.h
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@ -181,17 +181,10 @@
* functions that deal with signal disposition.
*/
#define SIG_ERR ((CODE void*)-1)
#define SIG_DFL ((CODE void*)0)
#define SIG_IGN ((CODE void*)0)
#if 0 /* Not yet supported */
# define SIG_HOLD ((CODE void*)0)
#endif
/* System V name compatibility */
#define sigset(s,f) signal(s,f)
#define SIG_ERR ((CODE void *)-1) /* And error occurred */
#define SIG_DFL ((CODE void *)0) /* Default is SIG_IGN for all signals */
#define SIG_IGN ((CODE void *)0) /* Ignore the signal */
#define SIG_HOLD ((CODE void *)1) /* Used only with sigset() */
/********************************************************************************
* Public Type Definitions
@ -289,29 +282,30 @@ extern "C"
#endif
int kill(pid_t, int);
int sigemptyset(FAR sigset_t *set);
int sigfillset(FAR sigset_t *set);
int sigaddset(FAR sigset_t *set, int signo);
int sigdelset(FAR sigset_t *set, int signo);
int sigismember(FAR const sigset_t *set, int signo);
int sigaction(int sig, FAR const struct sigaction *act,
FAR struct sigaction *oact);
int sigaddset(FAR sigset_t *set, int signo);
int sigdelset(FAR sigset_t *set, int signo);
int sigemptyset(FAR sigset_t *set);
int sigfillset(FAR sigset_t *set);
int sighold(int signo);
int sigismember(FAR const sigset_t *set, int signo);
int sigignore(int signo);
CODE void (*signal(int sig, CODE void (*func)(int signo)))(int signo);
int sigprocmask(int how, FAR const sigset_t *set, FAR sigset_t *oset);
int sigpause(int signo);
int sigrelse(int signo);
int sigpending(FAR sigset_t *set);
int sighold(int signo);
int sigsuspend(FAR const sigset_t *sigmask);
int sigwaitinfo(FAR const sigset_t *set, FAR struct siginfo *value);
int sigtimedwait(FAR const sigset_t *set, FAR struct siginfo *value,
FAR const struct timespec *timeout);
#ifdef CONFIG_CAN_PASS_STRUCTS
int sigqueue(int pid, int signo, union sigval value);
#else
int sigqueue(int pid, int signo, FAR void *sival_ptr);
#endif
int sigrelse(int signo);
CODE void (*sigset(int sig, CODE void (*func)(int signo)))(int signo);
int sigtimedwait(FAR const sigset_t *set, FAR struct siginfo *value,
FAR const struct timespec *timeout);
int sigsuspend(FAR const sigset_t *sigmask);
int sigwaitinfo(FAR const sigset_t *set, FAR struct siginfo *value);
#undef EXTERN
#ifdef __cplusplus

4
libc/signal/Make.defs
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@ -1,7 +1,7 @@
############################################################################
# libc/signal/Make.defs
#
# Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
# Copyright (C) 2011-2012, 2016 Gregory Nutt. All rights reserved.
# Author: Gregory Nutt <gnutt@nuttx.org>
#
# Redistribution and use in source and binary forms, with or without
@ -39,7 +39,7 @@ ifneq ($(CONFIG_DISABLE_SIGNALS),y)
CSRCS += sig_emptyset.c sig_fillset.c sig_addset.c sig_delset.c
CSRCS += sig_ismember.c sig_hold.c sig_relse.c sig_ignore.c sig_pause.c
CSRCS += signal.c
CSRCS += sig_set.c signal.c
# Add the signal directory to the build

20
libc/signal/sig_fillset.c
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@ -39,26 +39,6 @@
#include <signal.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Publics Functions
****************************************************************************/

20
libc/signal/sig_ismember.c
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@ -39,26 +39,6 @@
#include <signal.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/

4
libc/signal/sig_relse.c
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@ -47,8 +47,8 @@
* Name: sigrelse
*
* Description:
* The sigrelse() function will remove 'signo' to the calling process' signal
* mask.
* The sigrelse() function will remove 'signo' from the calling process'
* signal mask.
*
****************************************************************************/

156
libc/signal/sig_set.c Normal file
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@ -0,0 +1,156 @@
/****************************************************************************
* libc/signal/sig_set.c
*
* Copyright (C) 2015-2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 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 OWNER 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <signal.h>
#include <assert.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sigset
*
* Description:
* The signal() function will modify signal dispositions. The 'signo'
* argument specifies the signal. The 'func' argument specifies the
* signal's disposition, which may be SIG_DFL, SIG_IGN, or the address
* of a signal handler.
*
* The System V sigset function is very similar to the (obsolete) POSIX
* signal() function except that it includes additional managment of the
* tasks' signal mask. This function is then simply a wrapper around
* signal() with this additional signal mask logic added.
*
* - The sigset set function also accepts the SIG_HOLD value for 'func':
* If 'func' is equal to SIG_HOLD, 'signo' will be added to the signal
* mask of the calling process and 'signo's disposition will remain
* unchanged.
* - If 'func' is not equal to SIG_HOLD, 'signo' will be removed from the
* signal mask of the calling process.
*
* Input Parameters:
* signo - Identifies the signal to operate on
* func - The new disposition of the signal
*
* Returned Value:
* Upon successful completion, sigset() shall return SIG_HOLD if the
* signal had been blocked and the signal's previous disposition if it had
* not been blocked. Otherwise, SIG_ERR shall be returned and errno set to
* indicate the error.
*
* Hmm.. this wording is not clear to me. I assume this to mean:
*
* if (func == SIG_HOLD)
* {
* Set mask
* if (mask successfuly set)
* {
* return SIG_HOLD
* }
* else
* {
* return SIG_ERR
* }
* else
* {
* Set disposition
* if (disposition successfuly set)
* {
* return old disposition
* }
* else
* {
* return SIG_ERR
* }
* }
*
* But you could also argue that the English means to return SIG_HOLD in
* any case is the signal is blocked. And, in that case would you set the
* disposition or not? Unclear.
*
****************************************************************************/
CODE void (*sigset(int signo, CODE void (*func)(int signo)))(int signo)
{
_sa_handler_t disposition;
sigset_t set;
int ret;
DEBUGASSERT(GOOD_SIGNO(signo) && func != NULL);
(void)sigemptyset(&set);
(void)sigaddset(&set, signo);
/* Check if we are being asked to block the signal */
if (func == SIG_HOLD)
{
ret = sigprocmask(SIG_BLOCK, &set, NULL);
disposition = ret < 0 ? SIG_ERR : SIG_HOLD;
}
/* No.. then signal can handle the other cases */
else
{
/* Set the signal handler disposition */
disposition = signal(signo, func);
if (disposition != SIG_ERR)
{
/* And unblock the signal */
ret = sigprocmask(SIG_UNBLOCK, &set, NULL);
if (ret < 0)
{
/* Restore the original signal disposition and return and
* error.
*/
(void)signal(signo, disposition);
disposition = SIG_ERR;
}
}
}
return disposition;
}

25
libc/signal/signal.c
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@ -37,7 +37,10 @@
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <signal.h>
#include <assert.h>
/****************************************************************************
* Public Functions
@ -50,29 +53,20 @@
* The signal() function will modify signal dispositions. The 'signo'
* argument specifies the signal. The 'func' argument specifies the
* signal's disposition, which may be SIG_DFL, SIG_IGN, or the address
* of a signal handler. If 'func' is the address of a signal handler, the
* of a signal handler. If 'func' is the address of a signal handler, the
* system will add 'signo' to the calling process' signal mask before
* executing the signal handler; when the signal handler returns, the
* system will restore the calling process' signal mask to its state prior
* to the delivery of the signal. 'signo' will be removed from the calling
* process' signal mask.
*
* NOTE: The value SIG_HOLD for 'func' is not supported. It should work
* like this: If 'func' is equal to SIG_HOLD, 'signo' will be added to,
* not removed from, the calling process' signal mask and 'signo''s
* disposition will remain unchanged.
* to the delivery of the signal.
*
* Input Parameters:
* signo - Identifies the signal to operate on
* func - The new disposition of the signal
*
* Returned Value:
* Upon successful completion, signal() will the previous disposition of
* the signal. Otherwise, SIG_ERR will be returned and errno set to
* indicate the error.
*
* NOTE: signal() would return SIG_HOLD if the signal had been blocked and
* the signal's previous disposition if it had not been blocked.
* Upon successful completion, signal() will return the previous
* disposition of the signal handling. Otherwise, SIG_ERR will be returned
* and errno set to indicate the nature of the error.
*
****************************************************************************/
@ -82,6 +76,9 @@ CODE void (*signal(int signo, CODE void (*func)(int signo)))(int signo)
struct sigaction oact;
int ret;
DEBUGASSERT(GOOD_SIGNO(signo) && func != NULL);
DEBUGASSERT(func != SIG_ERR && func != SIG_HOLD);
/* Initialize the sigaction structure */
act.sa_handler = func;