From 9959c512ac3ba36f7a0db7614f0357ce0bae748f Mon Sep 17 00:00:00 2001
From: Jakub Hrozek <jhrozek@redhat.com>
Date: Mon, 9 Apr 2012 23:30:58 +0200
Subject: Move atomic io function to a separate module

We'll be using it on various places of the SSSD. The function is in its
own file to allow using just the one piece without having to drag in the
whole util.c module.
---
 src/util/atomic_io.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 src/util/atomic_io.c

(limited to 'src/util/atomic_io.c')

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;
+}
-- 
cgit