[libvirt] [PATCH] don't ignore write failure [was PATCH: 10/25: ...
"Daniel P. Berrange" <berrange(a)redhat.com> wrote:
The strerror() method is not guarenteed to be re-entrant, which is
...
@@ -759,8 +762,8 @@ static int networkStartNetworkDaemon(vir
if (network->def->forwardType != VIR_NETWORK_FORWARD_NONE &&
!networkEnableIpForwarding()) {
- networkReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR,
- _("failed to enable IP forwarding : %s"),
strerror(err));
+ virReportSystemError(conn, errno, "%s",
+ _("failed to enable IP forwarding"));
goto err_delbr2;
}
Looking at this chunk and the s/err/errno/ change (that's a bug fix),
I spotted another small bug:
Any write error in networkEnableIpForwarding was ignored,
I added a check for failed close, too, just in case.
Jim
From b4abd36014b56cdb33a91ab336eff6450a5d3c8a Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering(a)redhat.com>
Date: Mon, 19 Jan 2009 10:11:15 +0100
Subject: [PATCH] don't ignore write failure
* src/network_driver.c (networkEnableIpForwarding): This function
would always return 1 (success). Now it returns 0 upon write or
close failure, being careful to preserve any errno from a write failure.
Add comments.
---
src/network_driver.c | 20 ++++++++++++++------
1 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/src/network_driver.c b/src/network_driver.c
index 695acfb..51cfbbd 100644
--- a/src/network_driver.c
+++ b/src/network_driver.c
@@ -1,7 +1,7 @@
/*
* driver.c: core driver methods for managing qemu guests
*
- * Copyright (C) 2006, 2007, 2008 Red Hat, Inc.
+ * Copyright (C) 2006-2009 Red Hat, Inc.
* Copyright (C) 2006 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
@@ -774,20 +774,29 @@ networkRemoveIptablesRules(struct network_driver *driver,
iptablesSaveRules(driver->iptables);
}
+/* Enable IP Forwarding.
+ Return 0 for success, nonzero for failure.
+ Be careful to preserve any errno value upon failure. */
static int
networkEnableIpForwarding(void)
{
#define PROC_IP_FORWARD "/proc/sys/net/ipv4/ip_forward"
- int fd, ret;
+ int fd;
if ((fd = open(PROC_IP_FORWARD, O_WRONLY|O_TRUNC)) == -1)
return 0;
- if (safewrite(fd, "1\n", 2) < 0)
- ret = 0;
+ if (safewrite(fd, "1\n", 2) < 0) {
+ int saved_errno = errno;
+ close (fd);
+ errno = saved_errno;
+ return 0;
+ }
- close (fd);
+ /* Use errno from failed close only if there was no write error. */
+ if (close (fd) != 0)
+ return 0;
return 1;
@@ -1429,4 +1438,3 @@ int networkRegister(void) {
virRegisterStateDriver(&networkStateDriver);
return 0;
}
-
--
1.6.1.258.g7ff14