[Yum] Horrible response to keyboardInterrupt

[CAI Qian]

Hi,

The Bugzilla did not allow me to register, so I report a problem here.
Yum had bad response to CTRL-C in various of situations. For example,
in case of a DNS lookup failure,

- run "yum -y install openoffice.org-langpack-zh_CN", and cancel it
when starting to download RPM packages.

Downloading Packages:
(1/10): openoffice.org-draw-cor (0%) 28% [======                ]  13
kB/s | 304 kB     00:59 ETA (1/10):
openoffice.org-draw-core-3.0.0-4.2.fc10.x86_64.rpm                 |
336 kB     00:02     

 Current download cancelled, interrupt (ctrl-c) again within two
seconds to exit.

^C

Exiting on user cancel

- change all nameservers in /etc/resolv.conf to incorrect IPs.
- run "yum -y install openoffice.org-langpack-zh_CN" again, and try to
cancel it.

Then, the session could not be cancelled,

Downloading Packages:
^C^C^C^C^C^C^C^C^C^C^C^C^C^C
 Current download cancelled, interrupt (ctrl-c) again within two
seconds to exit.
^C^C^C^C^C^C^C^C^C^C
http://mirrors.usc.edu/pub/linux/distributions/fedora/linux/development/x86_64/os/Packages/openoffice.org-draw-core-3.0.0-4.2.fc10.x86_64.rpm:
[Errno 4] IOError: <urlopen error (-2, 'Name or service not known')>
Trying other mirror.
http://fedora.secsup.org/linux/development/x86_64/os/Packages/openoffice.org-draw-core-3.0.0-4.2.fc10.x86_64.rpm:
[Errno 4] IOError: <urlopen error (-2, 'Name or service not known')>
Trying other mirror.
...

No matter how many and quickly CTRL-C typed, it kept trying all
mirrors.

If I added the following dirty workaround patch, I could finally exit
it, although it was not responded immediately, and I had to hit CTRL-C
several times.

--- urlgrabber-3.0.0/urlgrabber/grabber.py~	2008-09-09
18:06:50.000000000 +0800
+++ urlgrabber-3.0.0/urlgrabber/grabber.py	2008-09-09
22:06:15.000000000 +0800
@@ -1218,6 +1218,8 @@
         except HTTPException, e:
             raise URLGrabError(7, _('HTTP Exception (%s): %s') % \
                             (e.__class__.__name__, e))
+        except KeyboardInterrupt:
+            exit (0)
         else:
             return (fo, hdr)

Maybe we should rewrite it in C to get better performance?

Software version,
yum-3.2.19
urlgrabber-3.0.0

Cai Qian