Ying Wang | 0543663 | 2013-04-05 16:01:00 -0700 | [diff] [blame] | 1 | /* Create a pipe, with specific opening flags. |
| 2 | Copyright (C) 2009-2012 Free Software Foundation, Inc. |
| 3 | |
| 4 | This program is free software; you can redistribute it and/or modify |
| 5 | it under the terms of the GNU General Public License as published by |
| 6 | the Free Software Foundation; either version 3, 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 General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License along |
| 15 | with this program; if not, see <http://www.gnu.org/licenses/>. */ |
| 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__ |
| 33 | /* Native Windows API. */ |
| 34 | |
| 35 | # include <io.h> |
| 36 | |
| 37 | #endif |
| 38 | |
| 39 | int |
| 40 | pipe2 (int fd[2], int flags) |
| 41 | { |
| 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 | |
| 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__ |
| 77 | /* Native Windows API. */ |
| 78 | |
| 79 | if (_pipe (fd, 4096, flags & ~O_NONBLOCK) < 0) |
| 80 | { |
| 81 | fd[0] = tmp[0]; |
| 82 | fd[1] = tmp[1]; |
| 83 | return -1; |
| 84 | } |
| 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 |
| 97 | { |
| 98 | verify (O_NONBLOCK == 0); |
| 99 | } |
| 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 | { |
| 141 | setmode (fd[1], O_BINARY); |
| 142 | setmode (fd[0], O_BINARY); |
| 143 | } |
| 144 | else if (flags & O_TEXT) |
| 145 | { |
| 146 | setmode (fd[1], O_TEXT); |
| 147 | setmode (fd[0], O_TEXT); |
| 148 | } |
| 149 | # endif |
| 150 | |
| 151 | return 0; |
| 152 | |
| 153 | #endif |
| 154 | |
| 155 | #if GNULIB_defined_O_NONBLOCK || \ |
| 156 | !((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__) |
| 157 | fail: |
| 158 | { |
| 159 | int saved_errno = errno; |
| 160 | close (fd[0]); |
| 161 | close (fd[1]); |
| 162 | fd[0] = tmp[0]; |
| 163 | fd[1] = tmp[1]; |
| 164 | errno = saved_errno; |
| 165 | return -1; |
| 166 | } |
| 167 | #endif |
| 168 | } |