Hi Eric,
On Wed, Oct 12, 2011 at 05:03:45PM -0600, Eric Blake wrote:
> On 10/12/2011 04:39 PM, Guido Günther wrote:
> >Based on a patch by Marc Deslauriers<[email protected]>
> >
> >RH: https://bugzilla.redhat.com/show_bug.cgi?id=562176
> >Ubuntu: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/517478
> >Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=573172
> >---
> > src/rpc/virnetsocket.c | 23 ++++++++++++++++++++---
> > tests/virnetsockettest.c | 11 ++++++-----
> > 2 files changed, 26 insertions(+), 8 deletions(-)
> >
> >+ virCommandAddArgList(cmd, nodename, "sh", "-c", NULL);
> >+ /*
> >+ * This ugly thing is a shell script to detect availability of
> >+ * the -q option for 'nc': debian and suse based distros need this
> >+ * flag to ensure the remote nc will exit on EOF, so it will go away
> >+ * when we close the connection tunnel. If it doesn't go away,
> >subsequent
> >+ * connection attempts will hang.
> >+ *
> >+ * Fedora's 'nc' doesn't have this option, and defaults to the desired
> >+ * behavior.
> >+ */
>
> The comment is essential :)
>
> >+ virCommandAddArgFormat(cmd,
> >+ "'if %s -q 2>&1 | grep \"requires an argument\">/dev/null 2>&1;
> >then"
> >+ " ARG=-q0;"
> >+ "fi;"
> >+ "%s $ARG -U %s'",
>
> This relies on ARG not being inherited from the environment.
> Probably safe, but just out of paranoia, and in a desire to compress
> things a bit, I'd go with either a pre-initialization:
>
> s/'if %s/'ARG=;if %s/
>
> or an else clause to the if-then-fi.
I went for the else clause since I think it's best for readability.
>
> Also, since we aren't using any space after ;, why do we need four
> spaces before ARG=-q0? We need at least one space (or a newline)
> after 'then', but either we should use newline after each part of
> the command (to match how it is listed in the source) or compress
> things to minimal size.
>
> >+ netcat ? netcat : "nc",
> >+ netcat ? netcat : "nc",
>
> Micro-optimization: prior to the virCommandAddArgFormat, I would have done:
>
> if (!netcat)
> netcat = "nc";
Done.
>
> then just directly used netcat here instead of dual ?:. But that's
> a nit that you don't have to worry about (patch 3/3 does the same
> thing).
>
> >+++ b/tests/virnetsockettest.c
> >@@ -496,7 +496,7 @@ mymain(void)
> > struct testSSHData sshData1 = {
> > .nodename = "somehost",
> > .path = "/tmp/socket",
> >- .expectOut = "somehost nc -U /tmp/socket\n",
> >+ .expectOut = "somehost sh -c 'if nc -q 2>&1 | grep \"requires an
> >argument\">/dev/null 2>&1; then ARG=-q0;fi;nc $ARG -U /tmp/socket'\n",
>
> Feel free to break this into multiple string literals; along
> expected newline boundaries might be nice:
>
> .expectOut = "somehost sh -c "
> "'if ...; then\n"
> " ARG=-q0\n"
> "fi\n"
> "nc $ARG ...";
Done.
>
> (or whatever it takes to match any changes you make above).
>
> ACK with nits fixed.
New version attached.
Cheers,
-- Guido
>From 52bcc244aa521147918e5a0ed8391676c6e17aa1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Guido=20G=C3=BCnther?= <[email protected]>
Date: Fri, 8 Jul 2011 21:07:29 +0200
Subject: [PATCH 1/4] Autodetect if the remote nc command supports the -q
option
Based on a patch by Marc Deslauriers <[email protected]>
RH: https://bugzilla.redhat.com/show_bug.cgi?id=562176
Ubuntu: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/517478
Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=573172
---
src/rpc/virnetsocket.c | 26 +++++++++++++++++++++++---
tests/virnetsockettest.c | 39 ++++++++++++++++++++++++++++++++++-----
2 files changed, 57 insertions(+), 8 deletions(-)
diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c
index e4289b1..2a9bca0 100644
--- a/src/rpc/virnetsocket.c
+++ b/src/rpc/virnetsocket.c
@@ -634,9 +634,29 @@ int virNetSocketNewConnectSSH(const char *nodename,
"-e", "none", NULL);
if (noVerify)
virCommandAddArgList(cmd, "-o", "StrictHostKeyChecking=no", NULL);
- virCommandAddArgList(cmd, nodename,
- netcat ? netcat : "nc",
- "-U", path, NULL);
+
+ if (!netcat)
+ netcat = "nc";
+
+ virCommandAddArgList(cmd, nodename, "sh", "-c", NULL);
+ /*
+ * This ugly thing is a shell script to detect availability of
+ * the -q option for 'nc': debian and suse based distros need this
+ * flag to ensure the remote nc will exit on EOF, so it will go away
+ * when we close the connection tunnel. If it doesn't go away, subsequent
+ * connection attempts will hang.
+ *
+ * Fedora's 'nc' doesn't have this option, and defaults to the desired
+ * behavior.
+ */
+ virCommandAddArgFormat(cmd,
+ "'if %s -q 2>&1 | grep \"requires an argument\" >/dev/null 2>&1; then "
+ "ARG=-q0;"
+ "else "
+ "ARG=;"
+ "fi;"
+ "%s $ARG -U %s'",
+ netcat, netcat, path);
return virNetSocketNewConnectCommand(cmd, retsock);
}
diff --git a/tests/virnetsockettest.c b/tests/virnetsockettest.c
index fae15a3..75cc9c0 100644
--- a/tests/virnetsockettest.c
+++ b/tests/virnetsockettest.c
@@ -496,7 +496,12 @@ mymain(void)
struct testSSHData sshData1 = {
.nodename = "somehost",
.path = "/tmp/socket",
- .expectOut = "somehost nc -U /tmp/socket\n",
+ .expectOut = "somehost sh -c 'if nc -q 2>&1 | grep \"requires an argument\" >/dev/null 2>&1; then "
+ "ARG=-q0;"
+ "else "
+ "ARG=;"
+ "fi;"
+ "nc $ARG -U /tmp/socket'\n",
};
if (virtTestRun("SSH test 1", 1, testSocketSSH, &sshData1) < 0)
ret = -1;
@@ -509,7 +514,13 @@ mymain(void)
.noTTY = true,
.noVerify = false,
.path = "/tmp/socket",
- .expectOut = "-p 9000 -l fred -T -o BatchMode=yes -e none somehost netcat -U /tmp/socket\n",
+ .expectOut = "-p 9000 -l fred -T -o BatchMode=yes -e none somehost sh -c '"
+ "if netcat -q 2>&1 | grep \"requires an argument\" >/dev/null 2>&1; then "
+ "ARG=-q0;"
+ "else "
+ "ARG=;"
+ "fi;"
+ "netcat $ARG -U /tmp/socket'\n",
};
if (virtTestRun("SSH test 2", 1, testSocketSSH, &sshData2) < 0)
ret = -1;
@@ -522,7 +533,13 @@ mymain(void)
.noTTY = false,
.noVerify = true,
.path = "/tmp/socket",
- .expectOut = "-p 9000 -l fred -o StrictHostKeyChecking=no somehost netcat -U /tmp/socket\n",
+ .expectOut = "-p 9000 -l fred -o StrictHostKeyChecking=no somehost sh -c '"
+ "if netcat -q 2>&1 | grep \"requires an argument\" >/dev/null 2>&1; then "
+ "ARG=-q0;"
+ "else "
+ "ARG=;"
+ "fi;"
+ "netcat $ARG -U /tmp/socket'\n",
};
if (virtTestRun("SSH test 3", 1, testSocketSSH, &sshData3) < 0)
ret = -1;
@@ -538,7 +555,13 @@ mymain(void)
struct testSSHData sshData5 = {
.nodename = "crashyhost",
.path = "/tmp/socket",
- .expectOut = "crashyhost nc -U /tmp/socket\n",
+ .expectOut = "crashyhost sh -c "
+ "'if nc -q 2>&1 | grep \"requires an argument\" >/dev/null 2>&1; then "
+ "ARG=-q0;"
+ "else "
+ "ARG=;"
+ "fi;"
+ "nc $ARG -U /tmp/socket'\n",
.dieEarly = true,
};
if (virtTestRun("SSH test 5", 1, testSocketSSH, &sshData5) < 0)
@@ -549,7 +572,13 @@ mymain(void)
.path = "/tmp/socket",
.keyfile = "/root/.ssh/example_key",
.noVerify = true,
- .expectOut = "-i /root/.ssh/example_key -o StrictHostKeyChecking=no example.com nc -U /tmp/socket\n",
+ .expectOut = "-i /root/.ssh/example_key -o StrictHostKeyChecking=no example.com sh -c '"
+ "if nc -q 2>&1 | grep \"requires an argument\" >/dev/null 2>&1; then "
+ "ARG=-q0;"
+ "else "
+ "ARG=;"
+ "fi;"
+ "nc $ARG -U /tmp/socket'\n",
};
if (virtTestRun("SSH test 6", 1, testSocketSSH, &sshData6) < 0)
ret = -1;
--
1.7.6.3
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