| 1 | /* POSIX compatible write() function. |
| 2 | Copyright (C) 2008-2014 Free Software Foundation, Inc. |
| 3 | Written by Bruno Haible <bruno@clisp.org>, 2008. |
| 4 | |
| 5 | This program is free software: you can redistribute it and/or modify |
| 6 | it under the terms of the GNU Lesser General Public License as published by |
| 7 | the Free Software Foundation; either version 3 of the License, or |
| 8 | (at your option) any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public License |
| 16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 17 | |
| 18 | #include <config.h> |
| 19 | |
| 20 | /* Specification. */ |
| 21 | #include <unistd.h> |
| 22 | |
| 23 | /* On native Windows platforms, SIGPIPE does not exist. When write() is |
| 24 | called on a pipe with no readers, WriteFile() fails with error |
| 25 | GetLastError() = ERROR_NO_DATA, and write() in consequence fails with |
| 26 | error EINVAL. */ |
| 27 | |
| 28 | #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ |
| 29 | |
| 30 | # include <errno.h> |
| 31 | # include <signal.h> |
| 32 | # include <io.h> |
| 33 | |
| 34 | # define WIN32_LEAN_AND_MEAN /* avoid including junk */ |
| 35 | # include <windows.h> |
| 36 | |
| 37 | # include "msvc-inval.h" |
| 38 | # include "msvc-nothrow.h" |
| 39 | |
| 40 | # undef write |
| 41 | |
| 42 | # if HAVE_MSVC_INVALID_PARAMETER_HANDLER |
| 43 | static ssize_t |
| 44 | write_nothrow (int fd, const void *buf, size_t count) |
| 45 | { |
| 46 | ssize_t result; |
| 47 | |
| 48 | TRY_MSVC_INVAL |
| 49 | { |
| 50 | result = write (fd, buf, count); |
| 51 | } |
| 52 | CATCH_MSVC_INVAL |
| 53 | { |
| 54 | result = -1; |
| 55 | errno = EBADF; |
| 56 | } |
| 57 | DONE_MSVC_INVAL; |
| 58 | |
| 59 | return result; |
| 60 | } |
| 61 | # else |
| 62 | # define write_nothrow write |
| 63 | # endif |
| 64 | |
| 65 | ssize_t |
| 66 | rpl_write (int fd, const void *buf, size_t count) |
| 67 | { |
| 68 | for (;;) |
| 69 | { |
| 70 | ssize_t ret = write_nothrow (fd, buf, count); |
| 71 | |
| 72 | if (ret < 0) |
| 73 | { |
| 74 | # if GNULIB_NONBLOCKING |
| 75 | if (errno == ENOSPC) |
| 76 | { |
| 77 | HANDLE h = (HANDLE) _get_osfhandle (fd); |
| 78 | if (GetFileType (h) == FILE_TYPE_PIPE) |
| 79 | { |
| 80 | /* h is a pipe or socket. */ |
| 81 | DWORD state; |
| 82 | if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL, |
| 83 | NULL, 0) |
| 84 | && (state & PIPE_NOWAIT) != 0) |
| 85 | { |
| 86 | /* h is a pipe in non-blocking mode. |
| 87 | We can get here in four situations: |
| 88 | 1. When the pipe buffer is full. |
| 89 | 2. When count <= pipe_buf_size and the number of |
| 90 | free bytes in the pipe buffer is < count. |
| 91 | 3. When count > pipe_buf_size and the number of free |
| 92 | bytes in the pipe buffer is > 0, < pipe_buf_size. |
| 93 | 4. When count > pipe_buf_size and the pipe buffer is |
| 94 | entirely empty. |
| 95 | The cases 1 and 2 are POSIX compliant. In cases 3 and |
| 96 | 4 POSIX specifies that write() must split the request |
| 97 | and succeed with a partial write. We fix case 4. |
| 98 | We don't fix case 3 because it is not essential for |
| 99 | programs. */ |
| 100 | DWORD out_size; /* size of the buffer for outgoing data */ |
| 101 | DWORD in_size; /* size of the buffer for incoming data */ |
| 102 | if (GetNamedPipeInfo (h, NULL, &out_size, &in_size, NULL)) |
| 103 | { |
| 104 | size_t reduced_count = count; |
| 105 | /* In theory we need only one of out_size, in_size. |
| 106 | But I don't know which of the two. The description |
| 107 | is ambiguous. */ |
| 108 | if (out_size != 0 && out_size < reduced_count) |
| 109 | reduced_count = out_size; |
| 110 | if (in_size != 0 && in_size < reduced_count) |
| 111 | reduced_count = in_size; |
| 112 | if (reduced_count < count) |
| 113 | { |
| 114 | /* Attempt to write only the first part. */ |
| 115 | count = reduced_count; |
| 116 | continue; |
| 117 | } |
| 118 | } |
| 119 | /* Change errno from ENOSPC to EAGAIN. */ |
| 120 | errno = EAGAIN; |
| 121 | } |
| 122 | } |
| 123 | } |
| 124 | else |
| 125 | # endif |
| 126 | { |
| 127 | # if GNULIB_SIGPIPE |
| 128 | if (GetLastError () == ERROR_NO_DATA |
| 129 | && GetFileType ((HANDLE) _get_osfhandle (fd)) |
| 130 | == FILE_TYPE_PIPE) |
| 131 | { |
| 132 | /* Try to raise signal SIGPIPE. */ |
| 133 | raise (SIGPIPE); |
| 134 | /* If it is currently blocked or ignored, change errno from |
| 135 | EINVAL to EPIPE. */ |
| 136 | errno = EPIPE; |
| 137 | } |
| 138 | # endif |
| 139 | } |
| 140 | } |
| 141 | return ret; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | #endif |