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 00000000..1543af9a
--- /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;
+}