From: kremlin <ian@kremlin.cc>
Date: Thu, 2 Oct 2014 22:30:57 +0000 (-0400)
Subject: write homework 5
X-Git-Url: https://uglyman.kremlin.cc/gitweb/gitweb.cgi?p=assignments.git;a=commitdiff_plain;h=9d67b8b8fe0b54315f831cc43949c0ab530b86ca

write homework 5
---

diff --git a/assgn5/Makefile b/assgn5/Makefile
new file mode 100644
index 0000000..8034288
--- /dev/null
+++ b/assgn5/Makefile
@@ -0,0 +1,9 @@
+PHONY: all
+
+CC=/usr/bin/gcc
+
+all:
+	$(CC) -Wall -Werror -Wextra -pedantic copy.c -o copy -Wno-unused-parameter -Wno-unused
+
+debug:
+	$(CC) -g -O0 -Wall -Werror -Wextra -pedantic copy.c -o copy -Wno-unused-parameter -Wno-unused
diff --git a/assgn5/assgn5.tar.gz b/assgn5/assgn5.tar.gz
new file mode 100644
index 0000000..644b24a
Binary files /dev/null and b/assgn5/assgn5.tar.gz differ
diff --git a/assgn5/copy.c b/assgn5/copy.c
new file mode 100644
index 0000000..0a3c8d5
--- /dev/null
+++ b/assgn5/copy.c
@@ -0,0 +1,78 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <sys/stat.h>
+
+int main(int argc, char *argv[]) {
+
+	int cur, flag_append, flag_force;
+	int fd_from, fd_to, mode;
+	char buf[1];
+
+	flag_append = 0;
+	flag_force  = 0;
+
+	while((cur = getopt(argc, argv, "af")) != -1) {
+		switch(cur) {
+
+			case 'a':
+				flag_append = 1;
+				break;
+
+			case 'f':
+				flag_force = 1;
+				break;
+
+			default:
+				printf("invalid argument\n");
+				return 1;
+		}
+	}
+
+	if(argc - optind != 2) {
+
+		printf("invalid number of args\n");
+		return 1;
+
+	} else if(flag_append && flag_force) {
+
+		printf("cannot simultaneously specify overwrite and append\n");
+		return 1;
+	}
+
+	if(access(argv[optind + 1], F_OK) != -1 && !flag_append && !flag_force) {
+
+		printf("destination file already exists, pass -f to overwrite\n");
+		return 1;
+	}
+
+	if(flag_force)       mode = O_TRUNC;
+	else if(flag_append) mode = O_APPEND;
+	else                 mode = O_CREAT;
+
+	fd_from = open(argv[optind], O_RDONLY);
+	fd_to   = open(argv[optind + 1], mode | O_WRONLY, S_IRWXU);
+
+	if(fd_from == -1) {
+
+		printf("could not open source file\n");
+		return 1;
+
+	} else if(fd_to == -1 && !flag_force && !flag_append) {
+
+		printf("could not create new destination file\n");
+		return 1;
+
+	} else if(fd_to == -1) {
+
+	}
+
+	while(read(fd_from, buf, 1) == 1)
+		write(fd_to, buf, 1);
+
+	close(fd_from);
+	close(fd_to);
+
+	return 0;
+}