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System calls and EINTR error code

Is there an expert there who can help me with the following:

I have the following system calls in C:

access()
unlink()
setsockopt()
fcntl()
setsid()
socket()
bind()
listen()

I want to know if they can crash with error code -1 and errno EINTR / EAGAIN.

Should I handle EINTR / EAGAIN for them?

There is no reference to EINTR / EAGAIN in the documentation, but many people I see process it.

What is the right one?

This is how I register the signal handlers: https://gitorious.org/zepto-web-server/zepto-web-server/source/b1b03b9ecccfe9646e34caf3eb04689e2bbc54dd:src/signal-dispatcher-utility.c

With this configuration: https://gitorious.org/zepto-web-server/zepto-web-server/source/b1b03b9ecccfe9646e34caf3eb04689e2bbc54dd:src/server-signals-support-utility.c

, EINTR/EAGAIN, , EINTR EAGAIN: https://gitorious.org/zepto-web-server/zepto-web-server/commit/b1b03b9ecccfe9646e34caf3eb04689e2bbc54dd

+4
4

. http://man7.org/linux/man-pages/man7/signal.7.html - , " ..." Linux, Unix/Posix/Linux.

+1

( sigaction SA_RESTART signal ), , EINTR .

, EINTR , fcntl, , . , .

+4

"" man * NIX. , : http://man7.org/linux/man-pages/man2/accept.2.html. man accept .

, , -1 + EINTR . , accept() , , setsid() , , .

+2

(7) Linux

accept
connect
fcntl
flock
futex
ioctl
open
read
readv
recv
recvfrom
recvmsg
send
sendmsg
sendto
wait
wait3
wait4
waitid
waitpid
write
writev

(EINTR) no-SA_RESTART

setsockopt
accept
recv
recvfrom
recvmsg
connect
send
sendto
sendmsg
pause
sigsuspend
sigtimedwait
sigwaitinfo
epoll_wait
epoll_pwait
poll
ppoll
select
lect
msgrcv
msgsnd
semop
semtimedop
clock_nanosleep
nanosleep
read
io_getevents
sleep

EINTR-, SA_RESTART.

, :

setsockopt
accept
recv
recvfrom
recvmsg
connect
send
sendto
sendmsg
epoll_wait
epoll_pwait
semop
semtimedop
sigtimedwait
sigwaitinfo
read
futex
msgrcv
msgsnd
nanosleep

EINTR + SIGCONT , Linux POSIX.1.

, EINTR, EINTR.

, , SIGSTOP/SIGCONT + no-op no-SA_RESTART , EINTR.

:

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

static void chld(int Sig)
{
    int status;
    if(0>wait(&status))
        _exit(1);
    if(!WIFEXITED(status)){ 
        //this can only interrupt an AS-safe block
        assert(WIFSIGNALED(status) && WTERMSIG(status) == SIGALRM);
        puts("OK");
        exit(0);
    } else {
        switch(WEXITSTATUS(status)){
        case 1: puts("FAIL"); break;
        case 2: puts("EINTR"); break;
        }
    }
    exit(0);
}
static void nop(int Sig)
{
}

int main()
{
    sigset_t full;
    sigfillset(&full);
    sigaction(SIGCHLD, &(struct sigaction){ .sa_handler=chld, .sa_mask=full, .sa_flags=0 } , 0); 
    sigaction(SIGUSR1, &(struct sigaction){ .sa_handler=nop, .sa_mask=full, .sa_flags=0 } , 0); 

    pid_t p;
    if(0>(p=fork())) { perror(0); return 1; }
    if(p!=0){
        //bombard it with SIGSTOP/SIGCONT/SIGUSR1
        for(;;){
            usleep(1); kill(p, SIGSTOP); kill(p, SIGCONT); kill(p, SIGUSR1);
        }
    }else{
        sigaction(SIGCHLD, &(struct sigaction){ .sa_handler=SIG_DFL }, 0);
        if(0>alarm(1))
            return 1;
        for(;;){

    #if 1
            /*not interruptible*/
            if(0>access("/dev/null", R_OK)){

                if(errno==EINTR)
                    return 2;
                perror(0);
                return 1;
            }

    #else
            int fd;
            unlink("fifo");
            if(0>mkfifo("fifo",0600))
                return 1;

            /*interruptible*/
            if(0>(fd=open("fifo", O_RDONLY|O_CREAT, 0600))){
                if(errno==EINTR)
                    return 2;
                perror(0);
                return 1;
            }
            close(fd);
    #endif

        }
    }
    return 0;
}

unlink access EINTR- ( ), , EINTR -retry .

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