add chapter8 exercises

Chapters/chapter8/exercise_8_7.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <signal.h>
+
+unsigned int snooze(unsigned int secs) {
+	int leftsecs = sleep(secs);
+	printf("Slept for %d of %d secs.\n", secs - leftsecs, secs);
+	return secs - leftsecs;
+}
+
+void sigint_handler(int sig) {
+
+}
+
+int main(void) {
+	if(signal(SIGINT, sigint_handler) == SIG_ERR) {
+		perror("signal error.");
+	}
+
+	snooze(10);
+}

Chapters/chapter8/exercise_8_8.c

@@ -0,0 +1,40 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+
+volatile long counter = 2;
+
+void handler1(int sig) {
+	sigset_t mask, prev_mask;
+
+	sigfillset(&mask);
+	sigprocmask(SIG_BLOCK, &mask, &prev_mask);
+	printf("%ld\n", --counter);
+	sigprocmask(SIG_SETMASK, &prev_mask, NULL);
+	_exit(0);
+}
+
+int main(void) {
+	pid_t pid;
+	sigset_t mask, prev_mask;
+
+	printf("%ld\n", counter);
+	fflush(stdout);
+
+	signal(SIGUSR1, handler1);
+	if((pid = fork()) == 0) {
+		while(1) {}
+	}
+	kill(pid, SIGUSR1);
+	waitpid(-1, NULL, 0);
+
+	sigfillset(&mask);
+	sigprocmask(SIG_BLOCK, &mask, &prev_mask);
+	printf("%ld\n", ++counter);
+	sigprocmask(SIG_SETMASK, &prev_mask, NULL);
+
+	exit(0);
+}

Chapters/chapter8/exittest.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int func() {
+	printf("This is func function.\n");
+//	exit(0);
+	return 0;
+}
+
+int main(void) {
+	func();
+	printf("会执行这句话吗？\n");
+	return 0;
+}

Chapters/chapter8/kill.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <unistd.h>
+
+int main(void) {
+	pid_t pid;
+	if((pid = fork()) == 0) {
+		pause();
+		printf("control should never reach here!\n");
+		exit(0);
+	}
+
+	kill(pid, SIGKILL);
+	exit(0);
+}

Chapters/chapter8/sigint.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <signal.h>
+
+void sigint_handler(int sig) {
+	printf("Caught SIGINT!\n");
+//	exit(0);
+}
+
+int main(void) {
+	if(signal(SIGINT, sigint_handler) == SIG_ERR) {
+		perror("signal error.");
+	}
+
+	pause();
+
+	printf("会执行这句话吗?\n");
+	return 0;
+}

Chapters/chapter8/signal1.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <errno.h>
+#include <sys/wait.h>
+
+#define MAXBUF 1024
+
+void handler1(int sig) {
+	int olderrno = errno;
+	if(waitpid(-1, NULL, 0) < 0) {
+		perror("waitpid error");
+	}
+	printf("handler reaped child\n");
+	sleep(1);
+	errno = olderrno;
+}
+
+int main(void) {
+	int i, n;
+	char buf[MAXBUF];
+
+	if(signal(SIGCHLD, handler1) == SIG_ERR) {
+		perror("signal error");
+	}
+
+	for(i = 0; i < 3; i++) {
+		if(fork() == 0) {
+			printf("Hello from child %d\n", (int)getpid());
+			exit(0);
+		}
+	}
+
+	if((n = read(0, buf, sizeof(buf))) < 0) {
+		perror("read");
+	}
+
+	printf("Parent processing input\n");
+	while(1) {
+		;
+	}
+
+	exit(0);
+}

Chapters/chapter8/signal2.c

@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <errno.h>
+#include <sys/wait.h>
+
+#define MAXBUF 1024
+
+void handler2(int sig) {
+	int olderrno = errno;
+	while(waitpid(-1, NULL, 0) > 0) {
+		printf("handler reaped child\n");
+	}
+	sleep(1);
+	errno = olderrno;
+}
+
+int main(void) {
+	int i, n;
+	char buf[MAXBUF];
+
+	if(signal(SIGCHLD, handler2) == SIG_ERR) {
+		perror("signal error");
+	}
+
+	for(i = 0; i < 3; i++) {
+		if(fork() == 0) {
+			printf("Hello from child %d\n", (int)getpid());
+			exit(0);
+		}
+	}
+
+	if((n = read(0, buf, sizeof(buf))) < 0) {
+		perror("read");
+	}
+
+	printf("Parent processing input\n");
+	while(1) {
+		;
+	}
+
+	exit(0);
+}