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author | Ondrej Kos <okos@redhat.com> | 2013-02-07 12:11:43 +0100 |
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committer | Jakub Hrozek <jhrozek@redhat.com> | 2013-02-11 15:45:10 +0100 |
commit | 075df914c0355e1dcafad1a128877be11241725c (patch) | |
tree | c8709f4da7e8c48c22958ecf9f58ac27347076a8 /src/util/atomic_io.c | |
parent | 9ec97a7502739c4966b5f3eb9d6b6ed282cf954b (diff) | |
download | sssd-075df914c0355e1dcafad1a128877be11241725c.tar.gz sssd-075df914c0355e1dcafad1a128877be11241725c.tar.xz sssd-075df914c0355e1dcafad1a128877be11241725c.zip |
UTIL: Add function for atomic I/O
Diffstat (limited to 'src/util/atomic_io.c')
-rw-r--r-- | src/util/atomic_io.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/src/util/atomic_io.c b/src/util/atomic_io.c new file mode 100644 index 000000000..1543af9a0 --- /dev/null +++ b/src/util/atomic_io.c @@ -0,0 +1,60 @@ +/* + Authors: + Jan Cholasta <jcholast@redhat.com> + + Copyright (C) 2012 Red Hat + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "util/atomic_io.h" + +/* based on code from libssh <http://www.libssh.org> */ +ssize_t sss_atomic_io_s(int fd, void *buf, size_t n, bool do_read) +{ + char *b = buf; + size_t pos = 0; + ssize_t res; + struct pollfd pfd; + + pfd.fd = fd; + pfd.events = do_read ? POLLIN : POLLOUT; + + while (n > pos) { + if (do_read) { + res = read(fd, b + pos, n - pos); + } else { + res = write(fd, b + pos, n - pos); + } + switch (res) { + case -1: + if (errno == EINTR) { + continue; + } + if (errno == EAGAIN || errno == EWOULDBLOCK) { + (void) poll(&pfd, 1, -1); + continue; + } + return -1; + case 0: + /* read returns 0 on end-of-file */ + errno = do_read ? 0 : EPIPE; + return pos; + default: + pos += (size_t) res; + } + } + + return pos; +} |