adding Makfile/README and copy utility

mjb/Makefile

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+TOPDIR=$(shell pwd)
+include $(TOPDIR)/include.mk
+
+all: copy
+
+copy: copy.o
+	$(CC) -o $@ $<
+

mjb/README

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+This directory contains my own implementation of examples/problems from Maurice J Bach's
+"The Design of Unix Operating System".
+
+Index (Chronological order)
+=====
+1. copy.c: Figure 1.3 Copy a file
+

mjb/copy.c

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+/**
+ * copy.c: My own implementation of Maurice J. Bach Figure 1.3 from
+ * The design of Unix Operating System.
+ * Usage: copy srcfile dstfile
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#define DEF_IO_BLOCK_SIZE 2048
+char buffer[DEF_IO_BLOCK_SIZE];
+int version = 1;
+
+// copy srcfd to dstfd: 0 on success, -1 on failure
+int copyfd(int srcfd, int dstfd)
+{
+    int count = 0;
+    char buffer[DEF_IO_BLOCK_SIZE];
+
+    while ((count = read(srcfd, buffer, sizeof buffer)) > 0) {
+        if (write(dstfd, buffer, count) == -1) {
+            fprintf(stderr, "write error on fd: %d\n", dstfd);
+            return -1;
+        }
+    }
+
+    // check of read error
+    if (count == -1) {
+        fprintf(stderr, "read error on fd: %d\n", srcfd);
+        return -1;
+    } else {
+        return 0;
+    }
+}
+
+int main(int argc, char *argv[])
+{
+    int ret, srcfd, dstfd;
+    char *srcfile, *dstfile;
+
+    if (argc < 3) {
+        fprintf(stderr, "%s requires 2 arguments\n", argv[0]);
+        fprintf(stdout, "Usage: %s srcfile dstfile\n", argv[0]);
+        exit(EXIT_FAILURE);
+    } else {
+        srcfile = argv[1];
+        dstfile = argv[2];
+    }
+
+    // open src file in read-only mode
+    srcfd = open(argv[1], O_RDONLY);
+    if (srcfd == -1) {
+        fprintf(stderr, "cannot open file: %s due to: %s\n", argv[1], strerror(errno));
+        exit(EXIT_FAILURE);
+    }
+
+    // create the dst. file
+    dstfd = creat(argv[2], 0666);
+    if (dstfd == -1) {
+        fprintf(stderr, "cannot create file: %s due to %s\n", argv[2],
+                strerror(errno));
+        close(srcfd);
+        exit(EXIT_FAILURE);
+    }
+
+    // copy the src file to dst. file
+    if (copyfd(srcfd, dstfd) == -1) {
+        fprintf(stderr, "failed to copy file: %s to file: %s\n", srcfile,
+                dstfile);
+        ret = EXIT_FAILURE;
+    } else {
+        ret = EXIT_SUCCESS;
+    }
+
+    // cleanup and exit
+    close(srcfd);
+    close(dstfd);
+    exit(ret);
+}

mjb/include.mk

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+CFLAGS=-g -Wall
+INCLUDES=-I $(TOPDIR)/include
+
+%.o: %.c
+	$(CC) -c $(CFLAGS) $(INCLUDES) $< -o $@