LibCore: Remove the barely-used Core::safe_syscall()

This was a helper that would call a syscall repeatedly until it either
succeeded or failed with a non-EINTR error.

It was only used in two places, so I don't think we need this helper.

Userland/Libraries/LibCore/EventLoop.cpp

@@ -41,7 +41,6 @@
 #include <LibCore/LocalSocket.h>
 #include <LibCore/Notifier.h>
 #include <LibCore/Object.h>
-#include <LibCore/SyscallUtils.h>
 #include <LibThread/Lock.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -658,8 +657,6 @@ try_select_again:
             goto try_select_again;
         }
         dbgln_if(EVENTLOOP_DEBUG, "Core::EventLoop::wait_for_event: {} ({}: {})", marked_fd_count, saved_errno, strerror(saved_errno));
-
-        // Blow up, similar to Core::safe_syscall.
         VERIFY_NOT_REACHED();
     }
     if (FD_ISSET(s_wake_pipe_fds[0], &rfds)) {

Userland/Libraries/LibCore/IODevice.cpp

@@ -27,7 +27,6 @@
 #include <AK/ByteBuffer.h>
 #include <AK/PrintfImplementation.h>
 #include <LibCore/IODevice.h>
-#include <LibCore/SyscallUtils.h>
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>
@@ -106,17 +105,21 @@ ByteBuffer IODevice::read(size_t max_size)
 bool IODevice::can_read_from_fd() const
 {
     // FIXME: Can we somehow remove this once Core::Socket is implemented using non-blocking sockets?
-    fd_set rfds;
+    fd_set rfds {};
     FD_ZERO(&rfds);
     FD_SET(m_fd, &rfds);
     struct timeval timeout {
         0, 0
     };
-    int rc = Core::safe_syscall(select, m_fd + 1, &rfds, nullptr, nullptr, &timeout);
-    if (rc < 0) {
-        // NOTE: We don't set m_error here.
-        perror("IODevice::can_read: select");
-        return false;
+
+    for (;;) {
+        if (select(m_fd + 1, &rfds, nullptr, nullptr, &timeout) < 0) {
+            if (errno == EINTR)
+                continue;
+            perror("IODevice::can_read_from_fd: select");
+            return false;
+        }
+        break;
     }
     return FD_ISSET(m_fd, &rfds);
 }
@@ -332,5 +335,4 @@ LineIterator& LineIterator::operator++()
     m_buffer = m_device->read_line();
     return *this;
 }
-
 }

Userland/Libraries/LibCore/SyscallUtils.h

@@ -1,57 +0,0 @@
-/*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- *    list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#pragma once
-
-#include <AK/Debug.h>
-#include <AK/StdLibExtras.h>
-#include <errno.h>
-#include <string.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-namespace Core {
-
-template<typename Syscall, class... Args>
-inline int safe_syscall(Syscall syscall, Args&&... args)
-{
-    for (;;) {
-        int sysret = syscall(forward<Args>(args)...);
-        if (sysret == -1) {
-            if constexpr (SAFE_SYSCALL_DEBUG) {
-                int saved_errno = errno;
-                dbgln_if(SAFE_SYSCALL_DEBUG, "Core::safe_syscall: {} ({}: {})", sysret, saved_errno, strerror(saved_errno));
-            }
-
-            if (errno == EINTR)
-                continue;
-            VERIFY_NOT_REACHED();
-        }
-        return sysret;
-    }
-}
-
-}

Userland/Libraries/LibIPC/Connection.h

@@ -32,7 +32,6 @@
 #include <LibCore/EventLoop.h>
 #include <LibCore/LocalSocket.h>
 #include <LibCore/Notifier.h>
-#include <LibCore/SyscallUtils.h>
 #include <LibCore/Timer.h>
 #include <LibIPC/Message.h>
 #include <stdint.h>
@@ -167,12 +166,19 @@ protected:
             fd_set rfds;
             FD_ZERO(&rfds);
             FD_SET(m_socket->fd(), &rfds);
-            int rc = Core::safe_syscall(select, m_socket->fd() + 1, &rfds, nullptr, nullptr, nullptr);
-            if (rc < 0) {
-                perror("select");
+            for (;;) {
+                if (auto rc = select(m_socket->fd() + 1, &rfds, nullptr, nullptr, nullptr); rc < 0) {
+                    if (errno == EINTR)
+                        continue;
+                    perror("wait_for_specific_endpoint_message: select");
+                    VERIFY_NOT_REACHED();
+                } else {
+                    VERIFY(rc > 0);
+                    VERIFY(FD_ISSET(m_socket->fd(), &rfds));
+                    break;
+                }
             }
-            VERIFY(rc > 0);
-            VERIFY(FD_ISSET(m_socket->fd(), &rfds));
+
             if (!drain_messages_from_peer())
                 break;
         }