From bf247fb45f0c21121281609949e5891237721d62 Mon Sep 17 00:00:00 2001 From: Andreas Kling Date: Sat, 15 Aug 2020 01:17:00 +0200 Subject: [PATCH] Kernel+LibC+UserspaceEmulator: Remove sys$dup() and sys$dup2() We can just implement these in userspace, so yay two less syscalls! --- DevTools/UserspaceEmulator/Emulator.cpp | 7 --- DevTools/UserspaceEmulator/Emulator.h | 1 - Kernel/API/Syscall.h | 2 - Kernel/CMakeLists.txt | 1 - Kernel/Process.h | 2 - Kernel/Syscalls/dup.cpp | 57 ------------------------- Libraries/LibC/unistd.cpp | 19 +++++++-- 7 files changed, 15 insertions(+), 74 deletions(-) delete mode 100644 Kernel/Syscalls/dup.cpp diff --git a/DevTools/UserspaceEmulator/Emulator.cpp b/DevTools/UserspaceEmulator/Emulator.cpp index 3878f2854cf5c1..ee972804a99962 100644 --- a/DevTools/UserspaceEmulator/Emulator.cpp +++ b/DevTools/UserspaceEmulator/Emulator.cpp @@ -253,8 +253,6 @@ u32 Emulator::virt_syscall(u32 function, u32 arg1, u32 arg2, u32 arg3) switch (function) { case SC_chdir: return virt$chdir(arg1, arg2); - case SC_dup2: - return virt$dup2(arg1, arg2); case SC_access: return virt$access(arg1, arg2, arg3); case SC_waitid: @@ -1350,9 +1348,4 @@ int Emulator::virt$chdir(FlatPtr path, size_t path_length) return syscall(SC_chdir, host_path.data(), host_path.size()); } -int Emulator::virt$dup2(int old_fd, int new_fd) -{ - return syscall(SC_dup2, old_fd, new_fd); -} - } diff --git a/DevTools/UserspaceEmulator/Emulator.h b/DevTools/UserspaceEmulator/Emulator.h index 0709b93bd8b174..34956d3a50cb7d 100644 --- a/DevTools/UserspaceEmulator/Emulator.h +++ b/DevTools/UserspaceEmulator/Emulator.h @@ -138,7 +138,6 @@ class Emulator { ssize_t virt$getrandom(FlatPtr buffer, size_t buffer_size, unsigned int flags); int virt$sleep(unsigned); int virt$chdir(FlatPtr, size_t); - int virt$dup2(int, int); int virt$getpgrp(); int virt$getpgid(pid_t); int virt$setpgid(pid_t pid, pid_t pgid); diff --git a/Kernel/API/Syscall.h b/Kernel/API/Syscall.h index 398b651315ceb7..4581d0c2048d5d 100644 --- a/Kernel/API/Syscall.h +++ b/Kernel/API/Syscall.h @@ -86,8 +86,6 @@ namespace Kernel { S(getpgrp) \ S(fork) \ S(execve) \ - S(dup) \ - S(dup2) \ S(sigaction) \ S(umask) \ S(getgroups) \ diff --git a/Kernel/CMakeLists.txt b/Kernel/CMakeLists.txt index 43a9d4bc1598d3..9743e146b2f936 100644 --- a/Kernel/CMakeLists.txt +++ b/Kernel/CMakeLists.txt @@ -100,7 +100,6 @@ set(KERNEL_SOURCES Syscalls/clock.cpp Syscalls/debug.cpp Syscalls/disown.cpp - Syscalls/dup.cpp Syscalls/execve.cpp Syscalls/exit.cpp Syscalls/fcntl.cpp diff --git a/Kernel/Process.h b/Kernel/Process.h index 9a72ca13ff15ef..40f60ae9ecc28b 100644 --- a/Kernel/Process.h +++ b/Kernel/Process.h @@ -258,8 +258,6 @@ class Process int sys$ptsname(int fd, Userspace, size_t); pid_t sys$fork(RegisterState&); int sys$execve(Userspace); - int sys$dup(int oldfd); - int sys$dup2(int oldfd, int newfd); int sys$sigaction(int signum, const sigaction* act, sigaction* old_act); int sys$sigprocmask(int how, Userspace set, Userspace old_set); int sys$sigpending(Userspace); diff --git a/Kernel/Syscalls/dup.cpp b/Kernel/Syscalls/dup.cpp deleted file mode 100644 index 374ba62a193fe4..00000000000000 --- a/Kernel/Syscalls/dup.cpp +++ /dev/null @@ -1,57 +0,0 @@ -/* - * Copyright (c) 2018-2020, Andreas Kling - * 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. - */ - -#include -#include - -namespace Kernel { - -int Process::sys$dup(int old_fd) -{ - REQUIRE_PROMISE(stdio); - auto description = file_description(old_fd); - if (!description) - return -EBADF; - int new_fd = alloc_fd(); - if (new_fd < 0) - return new_fd; - m_fds[new_fd].set(*description); - return new_fd; -} - -int Process::sys$dup2(int old_fd, int new_fd) -{ - REQUIRE_PROMISE(stdio); - auto description = file_description(old_fd); - if (!description) - return -EBADF; - if (new_fd < 0 || new_fd >= m_max_open_file_descriptors) - return -EINVAL; - m_fds[new_fd].set(*description); - return new_fd; -} - -} diff --git a/Libraries/LibC/unistd.cpp b/Libraries/LibC/unistd.cpp index 414f4bedd736cd..385aacff46eca2 100644 --- a/Libraries/LibC/unistd.cpp +++ b/Libraries/LibC/unistd.cpp @@ -410,14 +410,25 @@ int isatty(int fd) int dup(int old_fd) { - int rc = syscall(SC_dup, old_fd); - __RETURN_WITH_ERRNO(rc, rc, -1); + return fcntl(old_fd, F_DUPFD, 0); } int dup2(int old_fd, int new_fd) { - int rc = syscall(SC_dup2, old_fd, new_fd); - __RETURN_WITH_ERRNO(rc, rc, -1); + if (new_fd < 0) { + errno = EBADF; + return -1; + } + + if (old_fd == new_fd) + return old_fd; + + // Validate `old_fd` so we don't close `new_fd` and then fail the `F_DUPFD`. + if (fcntl(old_fd, F_GETFL) < 0) + return -1; + + close(new_fd); + return fcntl(old_fd, F_DUPFD, new_fd); } int setgroups(size_t size, const gid_t* list)