LibCore: Add nice get/set_process_name() wrappers in Core::Process

`Process::get_name()` and `Process::set_name()` are basically the same
as `get_process_name()` and `set_process_name()`, except making use of
convenient Serenity standard types and returning ErrorOr, instead of
char* and errno shenanigans.

`Process::set_name()` has an optional `SetThreadName` parameter, for
when you also want to set the thread's name to the same thing. That's
true for the two places that use `set_process_name()`.

Userland/Libraries/LibCore/Process.cpp

@@ -1,19 +1,23 @@
 /*
  * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
+ * Copyright (c) 2023, Sam Atkins <atkinssj@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <AK/DeprecatedString.h>
+#include <AK/String.h>
 #include <AK/Vector.h>
 #include <LibCore/Process.h>
 #include <LibCore/System.h>
 #include <errno.h>
 #include <spawn.h>
+#include <unistd.h>
 
 #ifdef AK_OS_SERENITY
 #    include <serenity.h>
+#    include <syscall.h>
 #endif
 
 extern char** environ;
@@ -97,4 +101,37 @@ ErrorOr<pid_t> Process::spawn(StringView path, Span<char const* const> arguments
     return argv.spawn();
 }
 
+ErrorOr<String> Process::get_name()
+{
+#if defined(AK_OS_SERENITY)
+    char buffer[BUFSIZ];
+    int rc = get_process_name(buffer, BUFSIZ);
+    if (rc != 0)
+        return Error::from_syscall("get_process_name"sv, -rc);
+    return String::from_utf8(StringView { buffer, strlen(buffer) });
+#else
+    // FIXME: Implement Process::get_name() for other platforms.
+    return String::from_utf8_short_string("???"sv);
+#endif
+}
+
+ErrorOr<void> Process::set_name([[maybe_unused]] StringView name, [[maybe_unused]] SetThreadName set_thread_name)
+{
+#if defined(AK_OS_SERENITY)
+    int rc = set_process_name(name.characters_without_null_termination(), name.length());
+    if (rc != 0)
+        return Error::from_syscall("set_process_name"sv, -rc);
+    if (set_thread_name == SetThreadName::No)
+        return {};
+
+    rc = syscall(SC_set_thread_name, gettid(), name.characters_without_null_termination(), name.length());
+    if (rc != 0)
+        return Error::from_syscall("set_thread_name"sv, -rc);
+    return {};
+#else
+    // FIXME: Implement Process::set_name() for other platforms.
+    return {};
+#endif
+}
+
 }

Userland/Libraries/LibCore/Process.h

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
  * Copyright (c) 2022, MacDue <macdue@dueutil.tech>
+ * Copyright (c) 2023, Sam Atkins <atkinssj@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -17,6 +18,13 @@ public:
     static ErrorOr<pid_t> spawn(StringView path, Span<DeprecatedString const> arguments, DeprecatedString working_directory = {});
     static ErrorOr<pid_t> spawn(StringView path, Span<StringView const> arguments, DeprecatedString working_directory = {});
     static ErrorOr<pid_t> spawn(StringView path, Span<char const* const> arguments = {}, DeprecatedString working_directory = {});
+
+    static ErrorOr<String> get_name();
+    enum class SetThreadName {
+        No,
+        Yes,
+    };
+    static ErrorOr<void> set_name(StringView, SetThreadName = SetThreadName::No);
 };
 
 }