From 7d463756900ad989455e94ec6e1082e830f582cf Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Wed, 6 Mar 2019 20:22:23 +0100
Subject: [PATCH] Userland: Support "cp foo somedirectory"

Don't overwrite the literal directory inode contents when copying a file
to a directory, duh. :^)
---
 Userland/cp.cpp | 43 +++++++++++++++++++++++++++++++++++++------
 1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/Userland/cp.cpp b/Userland/cp.cpp
index 86def7de34..b7810fdbcf 100644
--- a/Userland/cp.cpp
+++ b/Userland/cp.cpp
@@ -3,6 +3,9 @@
 #include <assert.h>
 #include <stdio.h>
 #include <sys/stat.h>
+#include <AK/AKString.h>
+#include <AK/StringBuilder.h>
+#include <AK/FileSystemPath.h>
 
 int main(int argc, char** argv)
 {
@@ -10,17 +13,14 @@ int main(int argc, char** argv)
         printf("usage: cp <source> <destination>\n");
         return 0;
     }
+    String src_path = argv[1];
+    String dst_path = argv[2];
 
-    int src_fd = open(argv[1], O_RDONLY);
+    int src_fd = open(src_path.characters(), 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;
-    }
 
     struct stat src_stat;
     int rc = fstat(src_fd, &src_stat);
@@ -29,6 +29,37 @@ int main(int argc, char** argv)
         return 1;
     }
 
+    if (S_ISDIR(src_stat.st_mode)) {
+        fprintf(stderr, "cp: FIXME: Copying directories is not yet supported\n");
+        return 1;
+    }
+
+    int dst_fd = open(dst_path.characters(), O_WRONLY | O_CREAT);
+    if (dst_fd < 0) {
+        perror("open dst");
+        return 1;
+    }
+
+    struct stat dst_stat;
+    rc = fstat(dst_fd, &dst_stat);
+    if (rc < 0) {
+        perror("stat dst");
+        return 1;
+    }
+
+    if (S_ISDIR(dst_stat.st_mode)) {
+        StringBuilder builder;
+        builder.append(dst_path);
+        builder.append('/');
+        builder.append(FileSystemPath(src_path).basename());
+        dst_path = builder.to_string();
+        dst_fd = open(dst_path.characters(), 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));