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-rw-r--r--Makefile.am2
-rw-r--r--src/util/atomic_io.c60
-rw-r--r--src/util/atomic_io.h40
-rw-r--r--src/util/util.h1
4 files changed, 103 insertions, 0 deletions
diff --git a/Makefile.am b/Makefile.am
index e00b7ca5c..d668acc25 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -237,6 +237,7 @@ SSSD_UTIL_OBJ = \
src/util/backup_file.c \
src/util/strtonum.c \
src/util/check_and_open.c \
+ src/util/atomic_io.c \
src/util/refcount.c \
$(SSSD_DEBUG_OBJ)
@@ -321,6 +322,7 @@ endif
dist_noinst_HEADERS = \
src/monitor/monitor.h \
+ src/util/atomic_io.h \
src/util/crypto/sss_crypto.h \
src/util/dlinklist.h \
src/util/util.h \
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;
+}
diff --git a/src/util/atomic_io.h b/src/util/atomic_io.h
new file mode 100644
index 000000000..ffae31d6c
--- /dev/null
+++ b/src/util/atomic_io.h
@@ -0,0 +1,40 @@
+/*
+ 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/>.
+*/
+
+#ifndef __SSSD_ATOMIC_IO_H__
+#define __SSSD_ATOMIC_IO_H__
+
+#include <unistd.h>
+#include <stdbool.h>
+#include <poll.h>
+#include <errno.h>
+
+/* Performs a read or write operation in an manner that is seemingly atomic
+ * to the caller.
+ *
+ * Please note that the function does not perform any asynchronous operation
+ * so the operation might potentially block
+ */
+ssize_t sss_atomic_io_s(int fd, void *buf, size_t n, bool do_read);
+
+#define sss_atomic_read_s(fd, buf, n) sss_atomic_io_s(fd, buf, n, true)
+#define sss_atomic_write_s(fd, buf, n) sss_atomic_io_s(fd, buf, n, false)
+
+#endif /* __SSSD_ATOMIC_IO_H__ */
diff --git a/src/util/util.h b/src/util/util.h
index 43fb007cb..43017aa0d 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -42,6 +42,7 @@
#include <tevent.h>
#include <ldb.h>
#include <dhash.h>
+#include "util/atomic_io.h"
#ifndef HAVE_ERRNO_T
#define HAVE_ERRNO_T