From e302fac34ba57ea9ce51384d49d1cfe5a33d859a Mon Sep 17 00:00:00 2001
From: Kenneth Myhra <kennethmyhra@gmail.com>
Date: Mon, 28 Mar 2022 22:12:28 +0200
Subject: [PATCH] kcov-example: Port to LibMain

---
 Userland/Utilities/CMakeLists.txt   |  1 +
 Userland/Utilities/kcov-example.cpp | 42 +++++++++--------------------
 2 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/Userland/Utilities/CMakeLists.txt b/Userland/Utilities/CMakeLists.txt
index 835d10cb07..6960d39486 100644
--- a/Userland/Utilities/CMakeLists.txt
+++ b/Userland/Utilities/CMakeLists.txt
@@ -124,6 +124,7 @@ target_link_libraries(install-bin LibMain)
 target_link_libraries(jp LibMain)
 target_link_libraries(js LibJS LibLine LibMain)
 link_with_unicode_data(js)
+target_link_libraries(kcov-example LibMain)
 target_link_libraries(keymap LibKeyboard LibMain)
 target_link_libraries(kill LibMain)
 target_link_libraries(killall LibCore LibMain)
diff --git a/Userland/Utilities/kcov-example.cpp b/Userland/Utilities/kcov-example.cpp
index b8d45a1aaf..09fd471795 100644
--- a/Userland/Utilities/kcov-example.cpp
+++ b/Userland/Utilities/kcov-example.cpp
@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <LibCore/System.h>
+#include <LibMain/Main.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <sys/ioctl.h>
@@ -14,47 +16,27 @@
 
 // Note: This program requires serenity to be built with the CMake build option
 // ENABLE_KERNEL_COVERAGE_COLLECTION
-int main(void)
+ErrorOr<int> serenity_main(Main::Arguments)
 {
     constexpr size_t num_entries = 1024 * 100;
 
-    int fd = open("/dev/kcov0", O_RDWR);
-    if (fd == -1) {
-        perror("open");
-        fprintf(stderr, "Could not open /dev/kcov0 - is ENABLE_KERNEL_COVERAGE_COLLECTION enabled?\n");
-        return 1;
-    }
-    if (ioctl(fd, KCOV_SETBUFSIZE, num_entries) == -1) {
-        perror("ioctl: KCOV_SETBUFSIZE");
-        return 1;
-    }
-    kcov_pc_t* cover = (kcov_pc_t*)mmap(NULL, num_entries * KCOV_ENTRY_SIZE,
-        PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-    if (cover == MAP_FAILED) {
-        perror("mmap");
-        return 1;
-    }
-    if (ioctl(fd, KCOV_ENABLE) == -1) {
-        perror("ioctl: KCOV_ENABLE");
-        return 1;
-    }
+    int fd = TRY(Core::System::open("/dev/kcov0", O_RDWR));
+    TRY(Core::System::ioctl(fd, KCOV_SETBUFSIZE, num_entries));
+    kcov_pc_t* cover = (kcov_pc_t*)TRY(Core::System::mmap(NULL, num_entries * KCOV_ENTRY_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0));
+    TRY(Core::System::ioctl(fd, KCOV_ENABLE));
     cover[0] = 0;
 
     // Example syscall so we actually cover some kernel code.
     getppid();
 
-    if (ioctl(fd, KCOV_DISABLE) == -1) {
-        perror("ioctl: KCOV_DISABLE");
-        return 1;
-    }
+    TRY(Core::System::ioctl(fd, KCOV_DISABLE));
+
     u64 cov_idx = cover[0];
     for (size_t idx = 1; idx <= cov_idx; idx++)
         printf("%p\n", (void*)cover[idx]);
-    if (munmap(const_cast<u64*>(cover), num_entries * KCOV_ENTRY_SIZE) == -1) {
-        perror("munmap");
-        return 1;
-    }
-    close(fd);
+
+    TRY(Core::System::munmap(const_cast<u64*>(cover), num_entries * KCOV_ENTRY_SIZE));
+    TRY(Core::System::close(fd));
 
     return 0;
 }