Add courses demos

courses/curs-01-demo/syscall-libc-call-asm/.gitignore

@@ -0,0 +1 @@
+/syscall-libc-call

courses/curs-01-demo/syscall-libc-call-asm/Makefile

@@ -0,0 +1,14 @@
+LDFLAGS = -m32
+
+.PHONY: all clean
+
+all: syscall-libc-call
+
+syscall-libc-call: syscall-libc-call.o
+
+syscall-libc-call.o: syscall-libc-call.asm
+	nasm -f elf32 -o $@ $<
+
+clean:
+	-rm -f *~
+	-rm -f syscall-libc-call.o syscall-libc-call

courses/curs-01-demo/syscall-libc-call-asm/syscall-libc-call.asm

@@ -0,0 +1,26 @@
+extern printf
+
+section .rodata
+    message db "anaaremere", 10, 0
+    len equ $-message
+
+section .text
+
+global main
+
+main:
+    push ebp
+    mov ebp, esp
+
+    push message
+    call printf
+    add esp, 4
+
+    mov ebx, 1
+    mov ecx, message
+    mov edx, len
+    mov eax, 4
+    int 0x80
+
+    leave
+    ret

courses/curs-02-demo/buffered-system-io/.gitignore

@@ -0,0 +1,3 @@
+/buffered
+/system
+/*.txt

courses/curs-02-demo/buffered-system-io/Makefile

@@ -0,0 +1,18 @@
+CC = gcc
+CPPFLAGS = -I../utils
+CFLAGS = -Wall -Wextra -g
+
+.PHONY: all clean
+
+all: buffered system
+
+buffered: buffered.o
+
+buffered.o: buffered.c ../utils/utils.h
+
+system: system.o
+
+system.o: system.c ../utils/utils.h
+
+clean:
+	-rm -f *.o *~ buffered system *.txt

courses/curs-02-demo/buffered-system-io/buffered.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "utils.h"
+
+int main(void)
+{
+	FILE *f;
+	size_t i;
+
+	for (i = 0; i < 10; i++) {
+		printf("a");
+		sleep(1);
+	}
+	printf("\n");
+
+	f = fopen("f.txt", "w+");
+	DIE(f == NULL, "fopen");
+
+	for (i = 0; i < 10; i++) {
+		fprintf(f, "a");
+		fprintf(f, "\n");
+		sleep(1);
+	}
+	fflush(f);
+
+	fclose(f);
+
+	return 0;
+}

courses/curs-02-demo/buffered-system-io/system.c

@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <fcntl.h>
+
+#include "utils.h"
+
+int main(void)
+{
+	int fd;
+	size_t i;
+
+	for (i = 0; i < 10; i++) {
+		write(STDOUT_FILENO, "a", 1);
+		sleep(1);
+	}
+	write(STDOUT_FILENO, "\n", 1);
+
+	fd = open("f.txt", O_RDWR | O_CREAT | O_TRUNC, 0644);
+	DIE(fd < 0, "open");
+
+	for (i = 0; i < 10; i++) {
+		write(fd, "a", 1);
+		write(fd, "\n", 1);
+		sleep(1);
+	}
+
+	close(fd);
+
+	return 0;
+}

courses/curs-02-demo/c-file-ops/.gitignore

@@ -0,0 +1,2 @@
+/c-file-ops
+/f.txt

courses/curs-02-demo/c-file-ops/Makefile

@@ -0,0 +1,14 @@
+CC = gcc
+CPPFLAGS = -I../utils
+CFLAGS = -Wall -Wextra -g
+
+.PHONY: all clean
+
+all: c-file-ops
+
+c-file-ops: c-file-ops.o
+
+c-file-ops.o: c-file-ops.c ../utils/utils.h
+
+clean:
+	-rm -f *.o *~ c-file-ops *.txt

courses/curs-02-demo/c-file-ops/c-file-ops.c

@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <fcntl.h>
+
+#include "utils.h"
+
+#define BUFSIZE		1024
+
+static char buffer[BUFSIZE] = { '1', };
+
+static void msg_and_wait(const char *msg)
+{
+	char buf[256];
+
+	puts(msg);
+	fputs("     Press ENTER to continue ...", stdout); fflush(stdout);
+
+	while(1) {
+		fgets(buf, 256, stdin);
+		if (buf[strlen(buf)-1] == '\n')
+			break;
+	}
+}
+
+int main(void)
+{
+	int fd;
+	ssize_t n;
+	int ret;
+
+	msg_and_wait("started program");
+
+	fd = open("f.txt", O_RDWR | O_CREAT | O_TRUNC, 0644);
+	DIE(fd < 0, "open");
+	msg_and_wait("opened f.txt");
+
+	n = write(fd, buffer, BUFSIZE);
+	DIE(n < 0, "write");
+	msg_and_wait("written 1024 bytes");
+
+	n = lseek(fd, -512, SEEK_CUR);
+	DIE(n < 0, "lseek");
+	msg_and_wait("went backwards 512 bytes");
+
+	n = read(fd, buffer, 256);
+	DIE(n < 0, "read");
+	msg_and_wait("read 256 bytes");
+
+	ret = ftruncate(fd, 256);
+	DIE(ret < 0, "ftruncate");
+	msg_and_wait("truncated file to 256 bytes");
+
+	close(fd);
+	msg_and_wait("closed files");
+
+	return 0;
+}

courses/curs-02-demo/fdtsize/.gitignore

@@ -0,0 +1 @@
+/fdtsize

courses/curs-02-demo/fdtsize/Makefile

@@ -0,0 +1,14 @@
+CFLAGS = -Wall -Wextra -g
+
+.PHONY: all clean
+
+all: fdtsize
+
+fdtsize: fdtsize.o
+
+fdtsize.o: fdtsize.c
+
+clean:
+	-rm -f *~
+	-rm -f fdtsize.o fdtsize
+

courses/curs-02-demo/fdtsize/fdtsize.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void)
+{
+	FILE *f;
+	size_t i;
+
+	for (i = 0; i < 1030; i++) {
+		printf("i = %zu, open file\n", i);
+		f = fopen("aaa", "r");
+		if (f == NULL) {
+			perror("fopen");
+			break;
+		}
+	}
+
+	printf("Opened %zu file descriptors.\n", i);
+
+	return 0;
+}

courses/curs-02-demo/fopen-perm/.gitignore

@@ -0,0 +1 @@
+/fopen-perm

courses/curs-02-demo/fopen-perm/Makefile

@@ -0,0 +1,15 @@
+CPPFLAGS = -I../utils
+CFLAGS = -Wall -Wextra -g
+
+.PHONY: all clean
+
+all: fopen-perm
+
+fopen-perm: fopen-perm.o
+
+fopen-perm.o: fopen-perm.c
+
+clean:
+	-rm -f *~
+	-rm -f fopen-perm.o fopen-perm
+

courses/curs-02-demo/fopen-perm/fopen-perm.c

@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "utils.h"
+
+int main(void)
+{
+	FILE *f;
+
+	f = fopen("aaa", "r");
+	fclose(f);
+
+	f = fopen("aaa", "w");
+	DIE(f == NULL, "fopen");
+	fclose(f);
+
+	f = fopen("aaa", "a");
+	DIE(f == NULL, "fopen");
+	fclose(f);
+
+	f = fopen("aaa", "rw");
+	DIE(f == NULL, "fopen");
+	fclose(f);
+
+	f = fopen("aaa", "r+");
+	DIE(f == NULL, "fopen");
+	fclose(f);
+
+	f = fopen("aaa", "w+");
+	DIE(f == NULL, "fopen");
+	fclose(f);
+
+	f = fopen("aaa", "a+");
+	DIE(f == NULL, "fopen");
+	fclose(f);
+
+	return 0;
+}

courses/curs-02-demo/open-dup/.gitignore

@@ -0,0 +1,2 @@
+/dup
+/open

courses/curs-02-demo/open-dup/Makefile

@@ -0,0 +1,18 @@
+CC = gcc
+CPPFLAGS = -I../utils
+CFLAGS = -Wall -Wextra -g
+
+.PHONY: all clean
+
+all: open dup
+
+open: open.o
+
+open.o: open.c ../utils/utils.h
+
+dup: dup.o
+
+dup.o: dup.c ../utils/utils.h
+
+clean:
+	-rm -f *.o *~ open dup *.txt

courses/curs-02-demo/open-dup/dup.c

@@ -0,0 +1,53 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "utils.h"
+
+static void msg_and_wait(const char *msg)
+{
+	char buf[256];
+
+	puts(msg);
+	fputs("     Press ENTER to continue ...", stdout); fflush(stdout);
+
+	while(1) {
+		fgets(buf, 256, stdin);
+		if (buf[strlen(buf)-1] == '\n')
+			break;
+	}
+}
+
+int main(void)
+{
+
+	int fd1, fd2, rc, pos;
+
+	msg_and_wait("open start");
+
+	fd1 = open("Makefile", O_RDWR);
+	DIE(fd1 < 0, "open file.txt");
+	msg_and_wait("open Makefile");
+
+	fd2 = dup(fd1);
+	DIE(fd2 < 0, "dup");
+	msg_and_wait("fd2 = dup(fd1)");
+
+	pos = lseek(fd1, 100, SEEK_SET);
+	DIE(pos < 0, "lseek");
+	msg_and_wait("lseek on fd1");
+
+	rc = close(fd1);
+	DIE(rc < 0, "fd1");
+	msg_and_wait("close fd1");
+
+	rc = close(fd2);
+	DIE(rc < 0, "fd2");
+	msg_and_wait("close fd2");
+
+	return 0;
+}