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[Qemu-devel] [PATCH] give some useful error messages when tap open
From: |
Luiz Capitulino |
Subject: |
[Qemu-devel] [PATCH] give some useful error messages when tap open |
Date: |
Wed, 2 Jun 2010 14:33:01 -0300 |
From: Michael Tokarev <address@hidden>
In net/tap-linux.c, when manipulation of /dev/net/tun fails, it prints
(with fprintf) something like this:
warning: could not open /dev/net/tun: no virtual network emulation
this has 2 issues:
1) it is not a warning really, it's a fatal error (kvm exits after
that),
2) there's no indication as of what's actually wrong: printing errno there
is helpful.
The patch below removes the "warning" prefix, uses %m (since it's linux,
%m is available as format modifier), and changes fprintf() to %qemu_error().
Now it prints something like this instead:
could not configure /dev/net/tun: Device or resource busy
(there are 2 messages like that in the same function)
This fixes Debian bug #578154, see
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=578154
Signed-off-by: Michael Tokarev <address@hidden>
Signed-off-by: Luiz Capitulino <address@hidden>
---
IMPORTANT: this an old fix that got forgotten, probably because it was
submitted in the middle of thread. I've just compiled tested it.
net/tap-linux.c | 8 +++++---
1 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/net/tap-linux.c b/net/tap-linux.c
index 03b8301..c92983c 100644
--- a/net/tap-linux.c
+++ b/net/tap-linux.c
@@ -33,14 +33,16 @@
#include "qemu-common.h"
#include "qemu-error.h"
+#define PATH_NET_TUN "/dev/net/tun"
+
int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int
vnet_hdr_required)
{
struct ifreq ifr;
int fd, ret;
- TFR(fd = open("/dev/net/tun", O_RDWR));
+ TFR(fd = open(PATH_NET_TUN, O_RDWR));
if (fd < 0) {
- fprintf(stderr, "warning: could not open /dev/net/tun: no virtual
network emulation\n");
+ error_report("could not open %s: %m", PATH_NET_TUN);
return -1;
}
memset(&ifr, 0, sizeof(ifr));
@@ -71,7 +73,7 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
int vnet_hdr_required
pstrcpy(ifr.ifr_name, IFNAMSIZ, "tap%d");
ret = ioctl(fd, TUNSETIFF, (void *) &ifr);
if (ret != 0) {
- fprintf(stderr, "warning: could not configure /dev/net/tun: no virtual
network emulation\n");
+ error_report("could not configure %s (%s): %m", PATH_NET_TUN,
ifr.ifr_name);
close(fd);
return -1;
}
--
1.7.1.231.gd0b16
- [Qemu-devel] [PATCH] give some useful error messages when tap open,
Luiz Capitulino <=