| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
| * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
| * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #include <errno.h> |
| #include <unistd.h> |
| |
| extern "C" int ___close(int); |
| |
| int close(int fd) { |
| int rc = ___close(fd); |
| if (rc == -1 && errno == EINTR) { |
| // POSIX says that if close returns with EINTR, the fd must not be closed. |
| // Linus disagrees: http://lkml.indiana.edu/hypermail/linux/kernel/0509.1/0877.html |
| // The future POSIX solution is posix_close (http://austingroupbugs.net/view.php?id=529), |
| // with the state after EINTR being undefined, and EINPROGRESS for the case where close |
| // was interrupted by a signal but the file descriptor was actually closed. |
| // My concern with that future behavior is that it breaks existing code that assumes |
| // that close only returns -1 if it failed. Unlike other system calls, I have real |
| // difficulty even imagining a caller that would need to know that close was interrupted |
| // but succeeded. So returning EINTR is wrong (because Linux always closes) and EINPROGRESS |
| // is harmful because callers need to be rewritten to understand that EINPROGRESS isn't |
| // actually a failure, but will be reported as one. |
| |
| // We don't restore errno because that would incur a cost (the TLS read) for every caller. |
| // Since callers don't know ahead of time whether close will legitimately fail, they need |
| // to have stashed the old errno value anyway if they plan on using it afterwards, so |
| // us clobbering errno here doesn't change anything in that respect. |
| return 0; |
| } |
| return rc; |
| } |