Userland: Add as-user execution to the pls utility

Commands may be executed as a specific user by passing the user's UID to
the '-u' flag in pls.

1 files changed, 10 insertions, 1 deletions

diff --git a/Userland/Utilities/pls.cpp b/Userland/Utilities/pls.cpp
index 4eb2ab59f6..a54e76711a 100644
--- a/Userland/Utilities/pls.cpp
+++ b/Userland/Utilities/pls.cpp
@@ -15,6 +15,8 @@ int main(int argc, char** argv)
 {
     Vector<char const*> command;
     Core::ArgsParser args_parser;
+    uid_t as_user_uid = 0;
+    args_parser.add_option(as_user_uid, "User to execute as", nullptr, 'u', "UID");
     args_parser.add_positional_argument(command, "Command to run at elevated privilege level", "command");
     args_parser.parse(argc, argv);
 
@@ -28,6 +30,13 @@ int main(int argc, char** argv)
         return 1;
     }
 
+    // Fail gracefully if as_user_uid is invalid
+    auto as_user_or_error = Core::Account::from_uid(as_user_uid);
+    if (as_user_or_error.is_error()) {
+        warnln("{}", as_user_or_error.error());
+        return 1;
+    }
+
     // If the current user is not a superuser, make them authenticate themselves.
     if (auto uid = getuid()) {
         auto account_or_error = Core::Account::from_uid(uid);
@@ -62,7 +71,7 @@ int main(int argc, char** argv)
         return 1;
     }
 
-    if (setuid(0) < 0) {
+    if (setuid(as_user_uid) < 0) {
         perror("setuid");
         return 1;
     }