1 /* Auxiliary code for filtering of data through a subprocess.
2 Copyright (C) 2001-2003, 2008-2010 Free Software Foundation, Inc.
3 Written by Bruno Haible <haible@clisp.cons.org>, 2009.
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU 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.
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 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20 # define SSIZE_MAX ((ssize_t) (SIZE_MAX / 2))
23 /* We use a child process, and communicate through a bidirectional pipe.
24 To avoid deadlocks, let the child process decide when it wants to read
25 or to write, and let the parent behave accordingly. The parent uses
26 select() to know whether it must write or read. On platforms without
27 select(), we use non-blocking I/O. (This means the parent is busy
28 looping while waiting for the child. Not good. But hardly any platform
29 lacks select() nowadays.) */
31 /* On BeOS select() works only on sockets, not on normal file descriptors. */
38 /* EINTR handling for close(), read(), write(), select().
39 These functions can return -1/EINTR even though we don't have any
40 signal handlers set up, namely when we get interrupted via SIGSTOP. */
43 nonintr_close (int fd)
49 while (retval < 0 && errno == EINTR);
53 #undef close /* avoid warning related to gnulib module unistd */
54 #define close nonintr_close
57 nonintr_read (int fd, void *buf, size_t count)
62 retval = read (fd, buf, count);
63 while (retval < 0 && errno == EINTR);
67 #define read nonintr_read
70 nonintr_write (int fd, const void *buf, size_t count)
75 retval = write (fd, buf, count);
76 while (retval < 0 && errno == EINTR);
80 #undef write /* avoid warning on VMS */
81 #define write nonintr_write
86 nonintr_select (int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
87 struct timeval *timeout)
92 retval = select (n, readfds, writefds, exceptfds, timeout);
93 while (retval < 0 && errno == EINTR);
97 # undef select /* avoid warning on VMS */
98 # define select nonintr_select
104 /* Non-blocking I/O. */
106 # define O_NONBLOCK O_NDELAY
109 # define IS_EAGAIN(errcode) 0
112 # define IS_EAGAIN(errcode) ((errcode) == EAGAIN || (errcode) == EWOULDBLOCK)
114 # define IS_EAGAIN(errcode) ((errcode) == EAGAIN)