Commit | Line | Data |
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3d458a81 | 1 | /* Create a pipe, with specific opening flags. |
5e69ceb7 | 2 | Copyright (C) 2009-2014 Free Software Foundation, Inc. |
3d458a81 AW |
3 | |
4 | This program is free software; you can redistribute it and/or modify | |
5 | it under the terms of the GNU Lesser General Public License as published by | |
6 | the Free Software Foundation; either version 2, or (at your option) | |
7 | any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | GNU Lesser General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public License along | |
005de2e8 | 15 | with this program; if not, see <http://www.gnu.org/licenses/>. */ |
3d458a81 AW |
16 | |
17 | #include <config.h> | |
18 | ||
19 | /* Specification. */ | |
20 | #include <unistd.h> | |
21 | ||
22 | #include <errno.h> | |
23 | #include <fcntl.h> | |
24 | ||
25 | #include "binary-io.h" | |
26 | #include "verify.h" | |
27 | ||
28 | #if GNULIB_defined_O_NONBLOCK | |
29 | # include "nonblocking.h" | |
30 | #endif | |
31 | ||
32 | #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ | |
f0007cad | 33 | /* Native Windows API. */ |
3d458a81 AW |
34 | |
35 | # include <io.h> | |
36 | ||
37 | #endif | |
38 | ||
39 | int | |
40 | pipe2 (int fd[2], int flags) | |
41 | { | |
231c0e0e LC |
42 | /* Mingw _pipe() corrupts fd on failure; also, if we succeed at |
43 | creating the pipe but later fail at changing fcntl, we want | |
44 | to leave fd unchanged: http://austingroupbugs.net/view.php?id=467 */ | |
45 | int tmp[2]; | |
46 | tmp[0] = fd[0]; | |
47 | tmp[1] = fd[1]; | |
48 | ||
3d458a81 AW |
49 | #if HAVE_PIPE2 |
50 | # undef pipe2 | |
51 | /* Try the system call first, if it exists. (We may be running with a glibc | |
52 | that has the function but with an older kernel that lacks it.) */ | |
53 | { | |
54 | /* Cache the information whether the system call really exists. */ | |
55 | static int have_pipe2_really; /* 0 = unknown, 1 = yes, -1 = no */ | |
56 | if (have_pipe2_really >= 0) | |
57 | { | |
58 | int result = pipe2 (fd, flags); | |
59 | if (!(result < 0 && errno == ENOSYS)) | |
60 | { | |
61 | have_pipe2_really = 1; | |
62 | return result; | |
63 | } | |
64 | have_pipe2_really = -1; | |
65 | } | |
66 | } | |
67 | #endif | |
68 | ||
69 | /* Check the supported flags. */ | |
70 | if ((flags & ~(O_CLOEXEC | O_NONBLOCK | O_BINARY | O_TEXT)) != 0) | |
71 | { | |
72 | errno = EINVAL; | |
73 | return -1; | |
74 | } | |
75 | ||
76 | #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ | |
f0007cad | 77 | /* Native Windows API. */ |
3d458a81 AW |
78 | |
79 | if (_pipe (fd, 4096, flags & ~O_NONBLOCK) < 0) | |
231c0e0e LC |
80 | { |
81 | fd[0] = tmp[0]; | |
82 | fd[1] = tmp[1]; | |
83 | return -1; | |
84 | } | |
3d458a81 AW |
85 | |
86 | /* O_NONBLOCK handling. | |
87 | On native Windows platforms, O_NONBLOCK is defined by gnulib. Use the | |
88 | functions defined by the gnulib module 'nonblocking'. */ | |
89 | # if GNULIB_defined_O_NONBLOCK | |
90 | if (flags & O_NONBLOCK) | |
91 | { | |
92 | if (set_nonblocking_flag (fd[0], true) != 0 | |
93 | || set_nonblocking_flag (fd[1], true) != 0) | |
94 | goto fail; | |
95 | } | |
96 | # else | |
35428fb6 LC |
97 | { |
98 | verify (O_NONBLOCK == 0); | |
99 | } | |
3d458a81 AW |
100 | # endif |
101 | ||
102 | return 0; | |
103 | ||
104 | #else | |
105 | /* Unix API. */ | |
106 | ||
107 | if (pipe (fd) < 0) | |
108 | return -1; | |
109 | ||
110 | /* POSIX <http://www.opengroup.org/onlinepubs/9699919799/functions/pipe.html> | |
111 | says that initially, the O_NONBLOCK and FD_CLOEXEC flags are cleared on | |
112 | both fd[0] and fd[1]. */ | |
113 | ||
114 | /* O_NONBLOCK handling. | |
115 | On Unix platforms, O_NONBLOCK is defined by the system. Use fcntl(). */ | |
116 | if (flags & O_NONBLOCK) | |
117 | { | |
118 | int fcntl_flags; | |
119 | ||
120 | if ((fcntl_flags = fcntl (fd[1], F_GETFL, 0)) < 0 | |
121 | || fcntl (fd[1], F_SETFL, fcntl_flags | O_NONBLOCK) == -1 | |
122 | || (fcntl_flags = fcntl (fd[0], F_GETFL, 0)) < 0 | |
123 | || fcntl (fd[0], F_SETFL, fcntl_flags | O_NONBLOCK) == -1) | |
124 | goto fail; | |
125 | } | |
126 | ||
127 | if (flags & O_CLOEXEC) | |
128 | { | |
129 | int fcntl_flags; | |
130 | ||
131 | if ((fcntl_flags = fcntl (fd[1], F_GETFD, 0)) < 0 | |
132 | || fcntl (fd[1], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1 | |
133 | || (fcntl_flags = fcntl (fd[0], F_GETFD, 0)) < 0 | |
134 | || fcntl (fd[0], F_SETFD, fcntl_flags | FD_CLOEXEC) == -1) | |
135 | goto fail; | |
136 | } | |
137 | ||
138 | # if O_BINARY | |
139 | if (flags & O_BINARY) | |
140 | { | |
5e69ceb7 MW |
141 | set_binary_mode (fd[1], O_BINARY); |
142 | set_binary_mode (fd[0], O_BINARY); | |
3d458a81 AW |
143 | } |
144 | else if (flags & O_TEXT) | |
145 | { | |
5e69ceb7 MW |
146 | set_binary_mode (fd[1], O_TEXT); |
147 | set_binary_mode (fd[0], O_TEXT); | |
3d458a81 AW |
148 | } |
149 | # endif | |
150 | ||
151 | return 0; | |
152 | ||
153 | #endif | |
154 | ||
35428fb6 LC |
155 | #if GNULIB_defined_O_NONBLOCK || \ |
156 | !((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__) | |
3d458a81 AW |
157 | fail: |
158 | { | |
159 | int saved_errno = errno; | |
160 | close (fd[0]); | |
161 | close (fd[1]); | |
231c0e0e LC |
162 | fd[0] = tmp[0]; |
163 | fd[1] = tmp[1]; | |
3d458a81 AW |
164 | errno = saved_errno; |
165 | return -1; | |
166 | } | |
35428fb6 | 167 | #endif |
3d458a81 | 168 | } |