From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 14 Apr 2014 03:00:42 +0000 (-0700)
Subject: util: ignore kernel errors reported via close(), unless it is EBADF
X-Git-Tag: v213~409
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=d96ea5048b2a901143059eecd32cb1607ceae041;p=elogind.git

util: ignore kernel errors reported via close(), unless it is EBADF

The kernel can return pretty much anything there, even though the fd is
closed. Let's not get confused by that.
---

diff --git a/src/shared/util.c b/src/shared/util.c
index 1a727ca40..c8a017db8 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -166,19 +166,19 @@ int close_nointr(int fd) {
 
         assert(fd >= 0);
         r = close(fd);
-
-        /* Just ignore EINTR; a retry loop is the wrong
-         * thing to do on Linux.
-         *
-         * http://lkml.indiana.edu/hypermail/linux/kernel/0509.1/0877.html
-         * https://bugzilla.gnome.org/show_bug.cgi?id=682819
-         * http://utcc.utoronto.ca/~cks/space/blog/unix/CloseEINTR
-         * https://sites.google.com/site/michaelsafyan/software-engineering/checkforeintrwheninvokingclosethinkagain
-         */
-        if (_unlikely_(r < 0 && errno == EINTR))
-                return 0;
-        else if (r >= 0)
+        if (r >= 0)
                 return r;
+        else if (errno == EINTR)
+                /*
+                 * Just ignore EINTR; a retry loop is the wrong
+                 * thing to do on Linux.
+                 *
+                 * http://lkml.indiana.edu/hypermail/linux/kernel/0509.1/0877.html
+                 * https://bugzilla.gnome.org/show_bug.cgi?id=682819
+                 * http://utcc.utoronto.ca/~cks/space/blog/unix/CloseEINTR
+                 * https://sites.google.com/site/michaelsafyan/software-engineering/checkforeintrwheninvokingclosethinkagain
+                 */
+                return 0;
         else
                 return -errno;
 }
@@ -195,7 +195,13 @@ int safe_close(int fd) {
 
         if (fd >= 0) {
                 PROTECT_ERRNO;
-                assert_se(close_nointr(fd) == 0);
+
+                /* The kernel might return pretty much any error code
+                 * via close(), but the fd will be closed anyway. The
+                 * only condition we want to check for here is whether
+                 * the fd was invalid at all... */
+
+                assert_se(close_nointr(fd) != -EBADF);
         }
 
         return -1;