diff --git a/Kernel/API/Syscall.h b/Kernel/API/Syscall.h index a37696aea0..d9be71d747 100644 --- a/Kernel/API/Syscall.h +++ b/Kernel/API/Syscall.h @@ -195,7 +195,7 @@ enum class NeedsBigProcessLock { S(utimensat, NeedsBigProcessLock::No) \ S(waitid, NeedsBigProcessLock::Yes) \ S(write, NeedsBigProcessLock::Yes) \ - S(writev, NeedsBigProcessLock::Yes) \ + S(pwritev, NeedsBigProcessLock::Yes) \ S(yield, NeedsBigProcessLock::No) namespace Syscall { diff --git a/Kernel/Process.h b/Kernel/Process.h index 7db511e1b6..98318fe520 100644 --- a/Kernel/Process.h +++ b/Kernel/Process.h @@ -317,7 +317,7 @@ public: ErrorOr sys$pread(int fd, Userspace, size_t, Userspace); ErrorOr sys$readv(int fd, Userspace iov, int iov_count); ErrorOr sys$write(int fd, Userspace, size_t); - ErrorOr sys$writev(int fd, Userspace iov, int iov_count); + ErrorOr sys$pwritev(int fd, Userspace iov, int iov_count, Userspace); ErrorOr sys$fstat(int fd, Userspace); ErrorOr sys$stat(Userspace); ErrorOr sys$lseek(int fd, Userspace, int whence); @@ -602,7 +602,7 @@ private: void delete_perf_events_buffer(); ErrorOr do_exec(NonnullLockRefPtr main_program_description, NonnullOwnPtrVector arguments, NonnullOwnPtrVector environment, LockRefPtr interpreter_description, Thread*& new_main_thread, u32& prev_flags, const ElfW(Ehdr) & main_program_header); - ErrorOr do_write(OpenFileDescription&, UserOrKernelBuffer const&, size_t); + ErrorOr do_write(OpenFileDescription&, UserOrKernelBuffer const&, size_t, Optional = {}); ErrorOr do_statvfs(FileSystem const& path, Custody const*, statvfs* buf); diff --git a/Kernel/Syscalls/write.cpp b/Kernel/Syscalls/write.cpp index 666fdb9f63..0efffa6f46 100644 --- a/Kernel/Syscalls/write.cpp +++ b/Kernel/Syscalls/write.cpp @@ -11,7 +11,9 @@ namespace Kernel { -ErrorOr Process::sys$writev(int fd, Userspace iov, int iov_count) +// NOTE: The offset is passed by pointer because off_t is 64bit, +// hence it can't be passed by register on 32bit platforms. +ErrorOr Process::sys$pwritev(int fd, Userspace iov, int iov_count, Userspace userspace_offset) { VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this); TRY(require_promise(Pledge::stdio)); @@ -31,26 +33,32 @@ ErrorOr Process::sys$writev(int fd, Userspace iov, return EINVAL; } + // NOTE: Negative offset means "operate like writev" which seeks the file. + auto base_offset = TRY(copy_typed_from_user(userspace_offset)); auto description = TRY(open_file_description(fd)); if (!description->is_writable()) return EBADF; + if (base_offset >= 0 && !description->file().is_seekable()) + return EINVAL; int nwritten = 0; + off_t current_offset = base_offset; for (auto& vec : vecs) { auto buffer = TRY(UserOrKernelBuffer::for_user_buffer((u8*)vec.iov_base, vec.iov_len)); - auto result = do_write(*description, buffer, vec.iov_len); + auto result = do_write(*description, buffer, vec.iov_len, base_offset >= 0 ? current_offset : Optional {}); if (result.is_error()) { if (nwritten == 0) return result.release_error(); return nwritten; } nwritten += result.value(); + current_offset += result.value(); } return nwritten; } -ErrorOr Process::do_write(OpenFileDescription& description, UserOrKernelBuffer const& data, size_t data_size) +ErrorOr Process::do_write(OpenFileDescription& description, UserOrKernelBuffer const& data, size_t data_size, Optional offset) { size_t total_nwritten = 0; @@ -72,7 +80,9 @@ ErrorOr Process::do_write(OpenFileDescription& description, UserOrKerne } // TODO: handle exceptions in unblock_flags } - auto nwritten_or_error = description.write(data.offset(total_nwritten), data_size - total_nwritten); + auto nwritten_or_error = offset.has_value() + ? description.write(offset.value() + total_nwritten, data.offset(total_nwritten), data_size - total_nwritten) + : description.write(data.offset(total_nwritten), data_size - total_nwritten); if (nwritten_or_error.is_error()) { if (total_nwritten > 0) return total_nwritten; diff --git a/Tests/Kernel/fuzz-syscalls.cpp b/Tests/Kernel/fuzz-syscalls.cpp index 8a1239ebc3..2ca2878bd0 100644 --- a/Tests/Kernel/fuzz-syscalls.cpp +++ b/Tests/Kernel/fuzz-syscalls.cpp @@ -44,7 +44,7 @@ static bool is_bad_idea(int fn, size_t const* direct_sc_args, size_t const* fake // FIXME: Known bug: https://github.com/SerenityOS/serenity/issues/5328 return direct_sc_args[0] == 1; case SC_write: - case SC_writev: + case SC_pwritev: // FIXME: Known bug: https://github.com/SerenityOS/serenity/issues/5328 return direct_sc_args[0] == 0; case SC_pledge: diff --git a/Userland/Libraries/LibC/sys/uio.cpp b/Userland/Libraries/LibC/sys/uio.cpp index 24be56d284..972abcfd44 100644 --- a/Userland/Libraries/LibC/sys/uio.cpp +++ b/Userland/Libraries/LibC/sys/uio.cpp @@ -13,10 +13,7 @@ extern "C" { ssize_t writev(int fd, const struct iovec* iov, int iov_count) { - __pthread_maybe_cancel(); - - int rc = syscall(SC_writev, fd, iov, iov_count); - __RETURN_WITH_ERRNO(rc, rc, -1); + return pwritev(fd, iov, iov_count, -1); } ssize_t readv(int fd, const struct iovec* iov, int iov_count) @@ -26,4 +23,12 @@ ssize_t readv(int fd, const struct iovec* iov, int iov_count) int rc = syscall(SC_readv, fd, iov, iov_count); __RETURN_WITH_ERRNO(rc, rc, -1); } + +ssize_t pwritev(int fd, struct iovec const* iov, int iov_count, off_t offset) +{ + __pthread_maybe_cancel(); + + int rc = syscall(SC_pwritev, fd, iov, iov_count, &offset); + __RETURN_WITH_ERRNO(rc, rc, -1); +} } diff --git a/Userland/Libraries/LibC/sys/uio.h b/Userland/Libraries/LibC/sys/uio.h index 2ef020f9d7..ad5090dfa2 100644 --- a/Userland/Libraries/LibC/sys/uio.h +++ b/Userland/Libraries/LibC/sys/uio.h @@ -13,5 +13,6 @@ __BEGIN_DECLS ssize_t writev(int fd, const struct iovec*, int iov_count); ssize_t readv(int fd, const struct iovec*, int iov_count); +ssize_t pwritev(int fd, const struct iovec*, int iov_count, off_t); __END_DECLS