Userland: Make a simple /bin/cp for copying files.

Kernel/sync.sh

@@ -43,6 +43,7 @@ cp -v ../Userland/touch mnt/bin/touch
 cp -v ../Userland/sync mnt/bin/sync
 cp -v ../Userland/more mnt/bin/more
 cp -v ../Userland/rm mnt/bin/rm
+cp -v ../Userland/cp mnt/bin/cp
 cp -v ../Userland/guitest mnt/bin/guitest
 cp -v ../Userland/guitest2 mnt/bin/guitest2
 cp -v ../Userland/sysctl mnt/bin/sysctl

Userland/.gitignore

@@ -25,3 +25,4 @@ guitest
 guitest2
 sysctl
 rm
+cp

Userland/Makefile

@@ -22,6 +22,7 @@ OBJS = \
        guitest.o \
        guitest2.o \
        sysctl.o \
+       cp.o \
        rm.o
 
 APPS = \
@@ -49,6 +50,7 @@ APPS = \
        guitest \
        guitest2 \
        sysctl \
+       cp \
        rm
 
 ARCH_FLAGS =
@@ -141,6 +143,9 @@ guitest2: guitest2.o
 sysctl: sysctl.o
 	$(LD) -o $@ $(LDFLAGS) $< ../LibC/LibC.a
 
+cp: cp.o
+	$(LD) -o $@ $(LDFLAGS) $< ../LibC/LibC.a
+
 rm: rm.o
 	$(LD) -o $@ $(LDFLAGS) $< ../LibC/LibC.a
 

Userland/cp.cpp

@@ -0,0 +1,42 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <stdio.h>
+
+int main(int argc, char** argv)
+{
+    if (argc != 3) {
+        printf("usage: cp <source> <destination>\n");
+        return 0;
+    }
+    int src_fd = open(argv[1], O_RDONLY);
+    if (src_fd < 0) {
+        perror("open src");
+        return 1;
+    }
+    int dst_fd = open(argv[2], O_WRONLY | O_CREAT);
+    if (dst_fd < 0) {
+        perror("open dst");
+        return 1;
+    }
+
+    for (;;) {
+        char buffer[BUFSIZ];
+        ssize_t nread = read(src_fd, buffer, sizeof(buffer));
+        if (nread < 0) {
+            perror("read src");
+            return 1;
+        }
+        if (nread == 0)
+            break;
+        ssize_t nwritten = write(dst_fd, buffer, nread);
+        if (nwritten < 0) {
+            perror("write dst");
+            return 1;
+        }
+        assert(nwritten != 0);
+    }
+    close(src_fd);
+    close(dst_fd);
+    return 0;
+}