From f501014fae4eb3d0a05ccc21683ed18172e86ff7 Mon Sep 17 00:00:00 2001
From: 0xtechnobabble <0xtechnobabble@protonmail.com>
Date: Sun, 12 Jan 2020 13:00:14 +0200
Subject: [PATCH] Userland: Add the chgrp command

The chgrp command allows the user to easily modify a file's group while
leaving its owner unchanged.
---
 Userland/chgrp.cpp | 48 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 Userland/chgrp.cpp

diff --git a/Userland/chgrp.cpp b/Userland/chgrp.cpp
new file mode 100644
index 0000000000..1afa03ee7f
--- /dev/null
+++ b/Userland/chgrp.cpp
@@ -0,0 +1,48 @@
+#include <AK/String.h>
+#include <grp.h>
+#include <pwd.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+int main(int argc, char** argv)
+{
+    if (pledge("stdio rpath chown", nullptr) < 0) {
+        perror("pledge");
+        return 1;
+    }
+
+    if (argc < 2) {
+        printf("usage: chgrp <gid> <path>\n");
+        return 0;
+    }
+
+    gid_t new_gid = -1;
+    auto gid_arg = String(argv[1]);
+
+    if (gid_arg.is_empty()) {
+        fprintf(stderr, "Empty gid option\n");
+        return 1;
+    }
+
+    bool ok;
+    new_gid = gid_arg.to_uint(ok);
+
+    if (!ok) {
+        new_gid = getgrnam(gid_arg.characters())->gr_gid;
+
+        if(!new_gid) {
+            fprintf(stderr, "Invalid gid: '%s'\n", gid_arg.characters());
+            return 1;
+        }
+    }
+
+    int rc = chown(argv[2], -1, new_gid);
+    if (rc < 0) {
+        perror("chgrp");
+        return 1;
+    }
+
+    return 0;
+}