cp: Implement directory copying

Recursive copying is only allowed if cp is called with the -r switch, ala POSIX.

Userland/cp.cpp

@@ -2,17 +2,21 @@
 #include <AK/FileSystemPath.h>
 #include <AK/StringBuilder.h>
 #include <LibCore/CArgsParser.h>
+#include <LibCore/CDirIterator.h>
 #include <assert.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
-bool copy_file(String, String);
+bool copy_file_or_directory(String, String, bool);
+bool copy_file(String, String, struct stat, int);
+bool copy_directory(String, String);
 
 int main(int argc, char** argv)
 {
     CArgsParser args_parser("cp");
+    args_parser.add_arg("r", "copy directories recursively");
     args_parser.add_required_single_value("source");
     args_parser.add_required_single_value("destination");
 
@@ -22,16 +26,19 @@ int main(int argc, char** argv)
         args_parser.print_usage();
         return 0;
     }
+    bool recursion_allowed = args.is_present("r");
     String src_path = values[0];
     String dst_path = values[1];
-    return copy_file(src_path, dst_path) ? 0 : 1;
+    return copy_file_or_directory(src_path, dst_path, recursion_allowed) ? 0 : 1;
 }
 
 /**
- * Copy a source file to a destination file. Returns true if successful, false 
+ * Copy a file or directory to a new location. Returns true if successful, false 
  * otherwise. If there is an error, its description is output to stderr.
+ * 
+ * Directories should only be copied if recursion_allowed is set.
  */
-bool copy_file(String src_path, String dst_path)
+bool copy_file_or_directory(String src_path, String dst_path, bool recursion_allowed)
 {
     int src_fd = open(src_path.characters(), O_RDONLY);
     if (src_fd < 0) {
@@ -47,10 +54,23 @@ bool copy_file(String src_path, String dst_path)
     }
 
     if (S_ISDIR(src_stat.st_mode)) {
-        fprintf(stderr, "cp: FIXME: Copying directories is not yet supported\n");
-        return false;
+        if (!recursion_allowed) {
+            fprintf(stderr, "cp: -r not specified; omitting directory '%s'\n", src_path.characters());
+            return false;
+        }
+        return copy_directory(src_path, dst_path);
     }
+    return copy_file(src_path, dst_path, src_stat, src_fd);
+}
 
+/**
+ * Copy a source file to a destination file. Returns true if successful, false 
+ * otherwise. If there is an error, its description is output to stderr.
+ * 
+ * To avoid repeated work, the source file's stat and file descriptor are required.
+ */
+bool copy_file(String src_path, String dst_path, struct stat src_stat, int src_fd)
+{
     int dst_fd = creat(dst_path.characters(), 0666);
     if (dst_fd < 0) {
         if (errno != EISDIR) {
@@ -94,7 +114,7 @@ bool copy_file(String src_path, String dst_path)
 
     auto my_umask = umask(0);
     umask(my_umask);
-    rc = fchmod(dst_fd, src_stat.st_mode & ~my_umask);
+    int rc = fchmod(dst_fd, src_stat.st_mode & ~my_umask);
     if (rc < 0) {
         perror("fchmod dst");
         return false;
@@ -104,3 +124,31 @@ bool copy_file(String src_path, String dst_path)
     close(dst_fd);
     return true;
 }
+
+/**
+ * Copy the contents of a source directory into a destination directory.
+ */
+bool copy_directory(String src_path, String dst_path)
+{
+    int rc = mkdir(dst_path.characters(), 0755);
+    if (rc < 0) {
+        perror("cp: mkdir");
+        return false;
+    }
+    CDirIterator di(src_path, CDirIterator::SkipDots);
+    if (di.has_error()) {
+        fprintf(stderr, "cp: CDirIterator: %s\n", di.error_string());
+        return false;
+    }
+    while (di.has_next()) {
+        String filename = di.next_path();
+        bool is_copied = copy_file_or_directory(
+            String::format("%s/%s", src_path.characters(), filename.characters()),
+            String::format("%s/%s", dst_path.characters(), filename.characters()),
+            true);
+        if (!is_copied) {
+            return false;
+        }
+    }
+    return true;
+}