[SP/P11] Solved exercises

4 files changed, 106 insertions, 0 deletions

diff --git a/Year 3/System programming/Practice11/ex1.c b/Year 3/System programming/Practice11/ex1.c
new file mode 100644
index 0000000..4086ca7
--- /dev/null
+++ b/Year 3/System programming/Practice11/ex1.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+#include <semaphore.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int main() {
+	sem_t* sem = sem_open("/sem", O_CREAT);
+
+	int sval = 0;
+	sem_getvalue(sem, &sval);
+	printf("%d\n", sval);
+
+	sem_close(sem);
+	sem_unlink("/sem");
+
+	return 0;
+}
diff --git a/Year 3/System programming/Practice11/ex2.c b/Year 3/System programming/Practice11/ex2.c
new file mode 100644
index 0000000..94ca590
--- /dev/null
+++ b/Year 3/System programming/Practice11/ex2.c
@@ -0,0 +1,30 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <semaphore.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int main() {
+	sem_t* sem = sem_open("/sem", O_CREAT, 0755, 0);
+
+	int fod = fork();
+	if (fod == 0) {
+		while (1) {
+			sem_wait(sem);
+			printf("world\n");
+		}
+	}
+	else {
+		while (1) {
+			printf("hello\n");
+			sem_post(sem);
+			sleep(1);
+		}
+	}
+
+	sem_close(sem);
+	if (fod != 0)
+		sem_unlink("/sem");
+
+	return 0;
+}
diff --git a/Year 3/System programming/Practice11/ex3-1.c b/Year 3/System programming/Practice11/ex3-1.c
new file mode 100644
index 0000000..68f26f6
--- /dev/null
+++ b/Year 3/System programming/Practice11/ex3-1.c
@@ -0,0 +1,30 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <semaphore.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int main() {
+	sem_t* sem1 = sem_open("/sem1", O_CREAT, 0755, 0);
+	sem_t* sem2 = sem_open("/sem2", O_CREAT, 0755, 0);
+
+	int fd = open("test.txt", O_WRONLY | O_CREAT, 0755);
+
+	while (1) {
+		sleep(1);
+
+		lseek(fd, 0, SEEK_END);
+		write(fd, "(1)", 3);
+		printf("written\n");
+
+		sem_post(sem2);
+		sem_wait(sem1);
+	}
+
+	close(fd);
+	sem_close(sem1);
+	sem_close(sem2);
+	sem_unlink("/sem1");
+
+	return 0;
+}
diff --git a/Year 3/System programming/Practice11/ex3-2.c b/Year 3/System programming/Practice11/ex3-2.c
new file mode 100644
index 0000000..6d19bda
--- /dev/null
+++ b/Year 3/System programming/Practice11/ex3-2.c
@@ -0,0 +1,29 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <semaphore.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int main() {
+	sem_t* sem1 = sem_open("/sem1", O_CREAT, 0755, 0);
+	sem_t* sem2 = sem_open("/sem2", O_CREAT, 0755, 0);
+
+	int fd = open("test.txt", O_WRONLY | O_CREAT, 0755);
+
+	while (1) {
+		sem_wait(sem2);
+
+		lseek(fd, 0, SEEK_END);
+		write(fd, "[2]", 3);
+		printf("written\n");
+
+		sem_post(sem1);
+	}
+
+	close(fd);
+	sem_close(sem1);
+	sem_close(sem2);
+	sem_unlink("/sem2");
+
+	return 0;
+}