Attachment 5116 Details for Bug 30369

Simple signal tester

signals.c (text/plain), 3.05 KB, created by Philipp Hahn on 2013-03-07 16:10 CET

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Creator: Philipp Hahn

Created: 2013-03-07 16:10 CET

Size: 3.05 KB

patch

obsolete

>#define _GNU_SOURCE
>
>#include <stdlib.h>
>#include <stdio.h>
>#include <stdint.h>
>#include <string.h>
>#include <unistd.h>
>#include <fcntl.h>
>#include <errno.h>
>#include <signal.h>
>#include <sys/select.h>
>
>#define MY_SIGNAL SIGUSR1
>
>/**
> * Print error message and exit.
> */
>static void my_error(int errnum, const char *msg) {
>	char buf[1024];
>
>	strerror_r(errnum, buf, sizeof(buf));
>	fprintf(stderr, "%s: [%d] %s\n", msg, errnum, buf);
>
>	exit(1);
>}
>
>/**
> * Signal handler.
> */
>static void my_handler(int signum) {
>	;
>}
>
>static void my_sigaction(int signum, siginfo_t *info, void *data) {
>	;
>}
>
>/**
> * Child reader.
> */
>static void do_child(int reader) {
>	int i, rv, data;
>	fd_set readfds;
>	struct timeval timeout;
>	struct sigaction oldact, act;
>
>	act.sa_handler = my_handler;
>	act.sa_sigaction = my_sigaction;
>	sigemptyset(&act.sa_mask);
>	sigaddset(&act.sa_mask, MY_SIGNAL);
>	act.sa_flags = 0;
>	act.sa_restorer = NULL;
>	rv = sigaction(MY_SIGNAL, &act, &oldact);
>	if (rv < 0)
>		my_error(errno, "C: sigaction() failed");
>
>	for (i = 100; i > 0; i--) {
>		FD_ZERO(&readfds);
>		FD_SET(reader, &readfds);
>
>		timeout.tv_sec = 1;
>		timeout.tv_usec = 0;
>
>again:
>		rv = select(reader + 1, &readfds, NULL, NULL, &timeout);
>		switch (rv) {
>			case -1: /* error */
>				switch (errno) {
>					case EINTR:
>						printf("C: EINTR\n");
>						goto again;
>					default:
>						my_error(errno, "C: select() failed");
>						break;
>				}
>				break;
>			case 0: /* timeout */
>				printf("C: timeout %d\n", i);
>				break;
>			case 1: /* readable */
>				rv = read(reader, &data, sizeof(data));
>				switch (rv) {
>					case -1: /* error */
>						my_error(errno, "C: read() failed");
>					case sizeof(data):
>						printf("C: read %d\n", data);
>						break;
>					default:
>						printf("C: strange read: %d\n", rv);
>						break;
>				}
>				break;
>			default:
>				printf("C: strange select: %d\n", rv);
>				break;
>		}
>	}
>}
>
>/**
> * Parent writer.
> */
>static void do_parent(int writer, pid_t child) {
>	int i, rv;
>	unsigned int usecs;
>
>	for (i = 100; i > 0; i--) {
>		usecs = random() % 2000000L;
>		rv = usleep(usecs);
>		if (rv < 0)
>			my_error(errno, "P: usleep() failed");
>
>		if (i & 1) {
>			printf("P: sending signal\n");
>			rv = kill(child, MY_SIGNAL);
>			if (rv < 0)
>				my_error(errno, "P: kill() failed");
>		} else {
>			printf("P: sending character\n");
>			rv = write(writer, &i, sizeof(i));
>			switch (rv) {
>				case -1: /* error */
>					my_error(errno, "P: write() failed");
>				case sizeof(i):
>					break;
>				default:
>					printf("P: strange write: %d\n", rv);
>					break;
>			}
>		}
>	}
>}
>
>/**
> * Main tester.
> */
>int main(int argc, char *argv[], char *envp[]) {
>	int rv;
>	pid_t pid;
>	int pipefd[2]; /* reader, writer */
>
>	rv = pipe2(pipefd, 0 /* | O_NONBLOCK | O_CLOEXEC */);
>	if (rv < 0)
>		my_error(errno, "pipe() failed");
>
>	pid = fork();
>	switch (pid) {
>		case -1: /* error */
>			my_error(errno, "fork() failed");
>
>		case 0: /* child */
>			close(pipefd[1]); /* close writer */
>			do_child(pipefd[0]); /* reader */
>			break;
>
>		default: /* parent */
>			close(pipefd[0]); /* close reader */
>			do_parent(pipefd[1], pid); /* writer */
>			break;
>	}
>	return 0;
>}

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