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.
This commit is contained in:
Jim Meyering 2009-01-20 19:29:08 +00:00
parent d82071710e
commit 3548e9aae8
2 changed files with 22 additions and 6 deletions

View File

@ -1,3 +1,11 @@
Tue Jan 20 20:28:07 +0100 2009 Jim Meyering <meyering@redhat.com>
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.
Tue Jan 20 19:26:53 GMT 2009 Daniel P. Berrange <berrange@redhat.com> Tue Jan 20 19:26:53 GMT 2009 Daniel P. Berrange <berrange@redhat.com>
* qemud/qemud.c, qemud/qemud.h: Dynamic spawn/cleanup threads * qemud/qemud.c, qemud/qemud.h: Dynamic spawn/cleanup threads

View File

@ -1,7 +1,7 @@
/* /*
* driver.c: core driver methods for managing qemu guests * 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 * Copyright (C) 2006 Daniel P. Berrange
* *
* This library is free software; you can redistribute it and/or * This library is free software; you can redistribute it and/or
@ -682,20 +682,29 @@ networkRemoveIptablesRules(struct network_driver *driver,
iptablesSaveRules(driver->iptables); iptablesSaveRules(driver->iptables);
} }
/* Enable IP Forwarding.
Return 0 for success, nonzero for failure.
Be careful to preserve any errno value upon failure. */
static int static int
networkEnableIpForwarding(void) networkEnableIpForwarding(void)
{ {
#define PROC_IP_FORWARD "/proc/sys/net/ipv4/ip_forward" #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) if ((fd = open(PROC_IP_FORWARD, O_WRONLY|O_TRUNC)) == -1)
return 0; return 0;
if (safewrite(fd, "1\n", 2) < 0) if (safewrite(fd, "1\n", 2) < 0) {
ret = 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; return 1;
@ -1317,4 +1326,3 @@ int networkRegister(void) {
virRegisterStateDriver(&networkStateDriver); virRegisterStateDriver(&networkStateDriver);
return 0; return 0;
} }