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9b36a80c | 1 | /* POSIX compatible write() function. |
49114fd4 | 2 | Copyright (C) 2008-2011 Free Software Foundation, Inc. |
9b36a80c LC |
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 | ||
dd7d0148 LC |
23 | /* Replace this function only if module 'nonblocking' or module 'sigpipe' is |
24 | requested. */ | |
25 | #if GNULIB_NONBLOCKING || GNULIB_SIGPIPE | |
9b36a80c LC |
26 | |
27 | /* On native Windows platforms, SIGPIPE does not exist. When write() is | |
28 | called on a pipe with no readers, WriteFile() fails with error | |
29 | GetLastError() = ERROR_NO_DATA, and write() in consequence fails with | |
30 | error EINVAL. */ | |
31 | ||
32 | # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ | |
33 | ||
34 | # include <errno.h> | |
35 | # include <signal.h> | |
36 | # include <io.h> | |
37 | ||
38 | # define WIN32_LEAN_AND_MEAN /* avoid including junk */ | |
39 | # include <windows.h> | |
40 | ||
41 | ssize_t | |
42 | rpl_write (int fd, const void *buf, size_t count) | |
43 | #undef write | |
44 | { | |
dd7d0148 | 45 | for (;;) |
9b36a80c | 46 | { |
dd7d0148 LC |
47 | ssize_t ret = write (fd, buf, count); |
48 | ||
49 | if (ret < 0) | |
1cd4fffc | 50 | { |
dd7d0148 LC |
51 | # if GNULIB_NONBLOCKING |
52 | if (errno == ENOSPC) | |
53 | { | |
54 | HANDLE h = (HANDLE) _get_osfhandle (fd); | |
55 | if (GetFileType (h) == FILE_TYPE_PIPE) | |
56 | { | |
57 | /* h is a pipe or socket. */ | |
58 | DWORD state; | |
59 | if (GetNamedPipeHandleState (h, &state, NULL, NULL, NULL, | |
60 | NULL, 0) | |
61 | && (state & PIPE_NOWAIT) != 0) | |
62 | { | |
63 | /* h is a pipe in non-blocking mode. | |
64 | We can get here in four situations: | |
65 | 1. When the pipe buffer is full. | |
66 | 2. When count <= pipe_buf_size and the number of | |
67 | free bytes in the pipe buffer is < count. | |
68 | 3. When count > pipe_buf_size and the number of free | |
69 | bytes in the pipe buffer is > 0, < pipe_buf_size. | |
70 | 4. When count > pipe_buf_size and the pipe buffer is | |
71 | entirely empty. | |
72 | The cases 1 and 2 are POSIX compliant. In cases 3 and | |
73 | 4 POSIX specifies that write() must split the request | |
74 | and succeed with a partial write. We fix case 4. | |
75 | We don't fix case 3 because it is not essential for | |
76 | programs. */ | |
77 | DWORD out_size; /* size of the buffer for outgoing data */ | |
78 | DWORD in_size; /* size of the buffer for incoming data */ | |
79 | if (GetNamedPipeInfo (h, NULL, &out_size, &in_size, NULL)) | |
80 | { | |
81 | size_t reduced_count = count; | |
82 | /* In theory we need only one of out_size, in_size. | |
83 | But I don't know which of the two. The description | |
84 | is ambiguous. */ | |
85 | if (out_size != 0 && out_size < reduced_count) | |
86 | reduced_count = out_size; | |
87 | if (in_size != 0 && in_size < reduced_count) | |
88 | reduced_count = in_size; | |
89 | if (reduced_count < count) | |
90 | { | |
91 | /* Attempt to write only the first part. */ | |
92 | count = reduced_count; | |
93 | continue; | |
94 | } | |
95 | } | |
96 | /* Change errno from ENOSPC to EAGAIN. */ | |
97 | errno = EAGAIN; | |
98 | } | |
99 | } | |
100 | } | |
101 | else | |
102 | # endif | |
103 | { | |
104 | # if GNULIB_SIGPIPE | |
105 | if (GetLastError () == ERROR_NO_DATA | |
106 | && GetFileType ((HANDLE) _get_osfhandle (fd)) | |
107 | == FILE_TYPE_PIPE) | |
108 | { | |
109 | /* Try to raise signal SIGPIPE. */ | |
110 | raise (SIGPIPE); | |
111 | /* If it is currently blocked or ignored, change errno from | |
112 | EINVAL to EPIPE. */ | |
113 | errno = EPIPE; | |
114 | } | |
115 | # endif | |
116 | } | |
1cd4fffc | 117 | } |
dd7d0148 | 118 | return ret; |
9b36a80c | 119 | } |
9b36a80c LC |
120 | } |
121 | ||
122 | # endif | |
123 | #endif |