| /* POSIX compatible write() function. |
| Copyright (C) 2008-2020 Free Software Foundation, Inc. |
| Written by Bruno Haible <bruno@clisp.org>, 2008. |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| #include <config.h> |
| |
| /* Specification. */ |
| #include <unistd.h> |
| |
| /* On native Windows platforms, SIGPIPE does not exist. When write() is |
| called on a pipe with no readers, WriteFile() fails with error |
| GetLastError() = ERROR_NO_DATA, and write() in consequence fails with |
| error EINVAL. */ |
| |
| #if defined _WIN32 && ! defined __CYGWIN__ |
| |
| # include <errno.h> |
| # include <signal.h> |
| # include <io.h> |
| |
| # define WIN32_LEAN_AND_MEAN /* avoid including junk */ |
| # include <windows.h> |
| |
| # if HAVE_MSVC_INVALID_PARAMETER_HANDLER |
| # include "msvc-inval.h" |
| # endif |
| # if GNULIB_MSVC_NOTHROW |
| # include "msvc-nothrow.h" |
| # else |
| # include <io.h> |
| # endif |
| |
| # undef write |
| |
| # if HAVE_MSVC_INVALID_PARAMETER_HANDLER |
| static ssize_t |
| write_nothrow (int fd, const void *buf, size_t count) |
| { |
| ssize_t result; |
| |
| TRY_MSVC_INVAL |
| { |
| result = write (fd, buf, count); |
| } |
| CATCH_MSVC_INVAL |
| { |
| result = -1; |
| errno = EBADF; |
| } |
| DONE_MSVC_INVAL; |
| |
| return result; |
| } |
| # else |
| # define write_nothrow write |
| # endif |
| |
| ssize_t |
| rpl_write (int fd, const void *buf, size_t count) |
| { |
| for (;;) |
| { |
| ssize_t ret = write_nothrow (fd, buf, count); |
| |
| if (ret < 0) |
| { |
| # if GNULIB_NONBLOCKING |
| if (errno == ENOSPC) |
| { |
| HANDLE h = (HANDLE) _get_osfhandle (fd); |
| if (GetFileType (h) == FILE_TYPE_PIPE) |
| { |
| /* h is a pipe or socket. */ |
| DWORD state; |
| if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL, |
| NULL, 0) |
| && (state & PIPE_NOWAIT) != 0) |
| { |
| /* h is a pipe in non-blocking mode. |
| We can get here in four situations: |
| 1. When the pipe buffer is full. |
| 2. When count <= pipe_buf_size and the number of |
| free bytes in the pipe buffer is < count. |
| 3. When count > pipe_buf_size and the number of free |
| bytes in the pipe buffer is > 0, < pipe_buf_size. |
| 4. When count > pipe_buf_size and the pipe buffer is |
| entirely empty. |
| The cases 1 and 2 are POSIX compliant. In cases 3 and |
| 4 POSIX specifies that write() must split the request |
| and succeed with a partial write. We fix case 4. |
| We don't fix case 3 because it is not essential for |
| programs. */ |
| DWORD out_size; /* size of the buffer for outgoing data */ |
| DWORD in_size; /* size of the buffer for incoming data */ |
| if (GetNamedPipeInfo (h, NULL, &out_size, &in_size, NULL)) |
| { |
| size_t reduced_count = count; |
| /* In theory we need only one of out_size, in_size. |
| But I don't know which of the two. The description |
| is ambiguous. */ |
| if (out_size != 0 && out_size < reduced_count) |
| reduced_count = out_size; |
| if (in_size != 0 && in_size < reduced_count) |
| reduced_count = in_size; |
| if (reduced_count < count) |
| { |
| /* Attempt to write only the first part. */ |
| count = reduced_count; |
| continue; |
| } |
| } |
| /* Change errno from ENOSPC to EAGAIN. */ |
| errno = EAGAIN; |
| } |
| } |
| } |
| else |
| # endif |
| { |
| # if GNULIB_SIGPIPE |
| if (GetLastError () == ERROR_NO_DATA |
| && GetFileType ((HANDLE) _get_osfhandle (fd)) |
| == FILE_TYPE_PIPE) |
| { |
| /* Try to raise signal SIGPIPE. */ |
| raise (SIGPIPE); |
| /* If it is currently blocked or ignored, change errno from |
| EINVAL to EPIPE. */ |
| errno = EPIPE; |
| } |
| # endif |
| } |
| } |
| return ret; |
| } |
| } |
| |
| #endif |