[virt-tools-list] guestfish question
Richard W.M. Jones
rjones at redhat.com
Fri Nov 5 15:19:48 UTC 2010
On Fri, Nov 05, 2010 at 08:53:20AM -0600, Eric Blake wrote:
> On 11/05/2010 07:55 AM, Richard W.M. Jones wrote:
> > On Thu, Nov 04, 2010 at 11:55:28AM -0400, Kenneth Armstrong wrote:
> >> rootdisk=$(guestfish --ro -a $diskimage -i inspect-os)
> >> distribution=$(guestfish --ro -a $diskimage -i inspect-get-distro $rootdisk)
> >> echo $distribution
> >
> > By the way it's quicker to do:
> >
> > eval $(guestfish --ro -a $diskimage -i --listen)
>
> You should probably get in the habit of using:
>
> eval "$(guestfish ... --listen)"
>
> so that if guestfish ever changes its output to include shell globbing
> characters, the result won't cause inadvertent file name matching (for a
> more concrete example, dircolors outputs literal *, so you should always
> use eval "$(dircolors)" rather than eval $(dircolors) in startup
> scripts; otherwise the existence of a file that matches the glob and
> contains a semicolon could cause the eval to perform arbitrary commands).
>
> Also, I noticed that guestfish --listen assumes a POSIX shell, in that
> it currently outputs 'export GUESTFISH_PID=15404'. But this is not
> portable to Solaris /bin/sh; it would be more portable to follow
> dircolors' lead of using 'GUESTFISH_PID=15404; export GUESTFISH_PID'.
>
> It might also be worth copying dircolors' lead by implementing
> 'guestfish --listen --csh' which caters to the csh-family of shells by
> producing 'setenv GUESTFISH_PID 15404'.
Thanks. I have take up all these suggestions. Would you mind
looking over the small patches attached?
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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>From 633ae13c80d40b0f30db73e520c08cf365d2f8a3 Mon Sep 17 00:00:00 2001
From: Richard W.M. Jones <rjones at redhat.com>
Date: Fri, 5 Nov 2010 15:04:08 +0000
Subject: [PATCH 1/3] fish: More portable export sh statment.
Don't depend on bash, but allow sh/dash/etc format:
GUESTFISH_PID=nn; export GUESTFISH_PID
(Thanks Eric Blake).
---
fish/rc.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/fish/rc.c b/fish/rc.c
index e637fc6..2d2f227 100644
--- a/fish/rc.c
+++ b/fish/rc.c
@@ -198,7 +198,7 @@ rc_listen (void)
if (pid > 0) {
/* Parent process. */
- printf ("export GUESTFISH_PID=%d\n", pid);
+ printf ("GUESTFISH_PID=%d; export GUESTFISH_PID\n", pid);
fflush (stdout);
_exit (0);
}
--
1.7.3.2
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>From c9b663852d401ecdb80b381447a9620a612e5978 Mon Sep 17 00:00:00 2001
From: Richard W.M. Jones <rjones at redhat.com>
Date: Fri, 5 Nov 2010 15:07:11 +0000
Subject: [PATCH 2/3] fish: Suggest safer form of eval.
eval "$(guestfish --listen)"
instead of various other forms.
(Thanks Eric Blake).
---
fish/guestfish.pod | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/fish/guestfish.pod b/fish/guestfish.pod
index 7319bd7..6368cc9 100644
--- a/fish/guestfish.pod
+++ b/fish/guestfish.pod
@@ -140,7 +140,7 @@ To list what is available do:
=head2 Remote control
- eval `guestfish --listen`
+ eval "$(guestfish --listen)"
guestfish --remote add-ro disk.img
guestfish --remote run
guestfish --remote lvs
@@ -730,7 +730,7 @@ up a guestfish process each time.
Start a guestfish server process using:
- eval `guestfish --listen`
+ eval "$(guestfish --listen)"
and then send it commands by doing:
@@ -750,9 +750,9 @@ The C<eval> statement sets the environment variable C<$GUESTFISH_PID>,
which is how the I<--remote> option knows where to send the commands.
You can have several guestfish listener processes running using:
- eval `guestfish --listen`
+ eval "$(guestfish --listen)"
pid1=$GUESTFISH_PID
- eval `guestfish --listen`
+ eval "$(guestfish --listen)"
pid2=$GUESTFISH_PID
...
guestfish --remote=$pid1 cmd
--
1.7.3.2
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>From 8caea9d22f95673cba083877b4c34fb6f22e1921 Mon Sep 17 00:00:00 2001
From: Richard W.M. Jones <rjones at redhat.com>
Date: Fri, 5 Nov 2010 15:17:45 +0000
Subject: [PATCH 3/3] fish: Add --listen --csh to for csh, tcsh compatibility.
(Thanks Eric Blake).
---
fish/fish.c | 5 +++++
fish/fish.h | 1 +
fish/guestfish.pod | 12 ++++++++++++
fish/rc.c | 7 ++++++-
4 files changed, 24 insertions(+), 1 deletions(-)
diff --git a/fish/fish.c b/fish/fish.c
index d9a92dd..9f20bba 100644
--- a/fish/fish.c
+++ b/fish/fish.c
@@ -67,6 +67,7 @@ int read_only = 0;
int quit = 0;
int verbose = 0;
int remote_control_listen = 0;
+int remote_control_csh = 0;
int remote_control = 0;
int exit_on_error = 1;
int command_num = 0;
@@ -105,6 +106,7 @@ usage (int status)
" -h|--cmd-help cmd Display detailed help on 'cmd'\n"
" -a|--add image Add image\n"
" -c|--connect uri Specify libvirt URI for -d option\n"
+ " --csh Make --listen csh-compatible\n"
" -d|--domain guest Add disks from libvirt guest\n"
" -D|--no-dest-paths Don't tab-complete paths from guest fs\n"
" --echo-keys Don't turn off echo for passphrases\n"
@@ -153,6 +155,7 @@ main (int argc, char *argv[])
{ "add", 1, 0, 'a' },
{ "cmd-help", 2, 0, 'h' },
{ "connect", 1, 0, 'c' },
+ { "csh", 0, 0, 0 },
{ "domain", 1, 0, 'd' },
{ "echo-keys", 0, 0, 0 },
{ "file", 1, 0, 'f' },
@@ -262,6 +265,8 @@ main (int argc, char *argv[])
format = NULL;
else
format = optarg;
+ } else if (STREQ (long_options[option_index].name, "csh")) {
+ remote_control_csh = 1;
} else {
fprintf (stderr, _("%s: unknown long option: %s (%d)\n"),
program_name, long_options[option_index].name, option_index);
diff --git a/fish/fish.h b/fish/fish.h
index 8fedf5d..3597805 100644
--- a/fish/fish.h
+++ b/fish/fish.h
@@ -61,6 +61,7 @@ extern int command_num;
extern int utf8_mode;
extern int have_terminfo;
extern int progress_bars;
+extern int remote_control_csh;
extern const char *libvirt_uri;
extern int issue_command (const char *cmd, char *argv[], const char *pipe);
extern void pod2text (const char *name, const char *shortdesc, const char *body);
diff --git a/fish/guestfish.pod b/fish/guestfish.pod
index 6368cc9..0ec7b3b 100644
--- a/fish/guestfish.pod
+++ b/fish/guestfish.pod
@@ -174,6 +174,11 @@ When used in conjunction with the I<-d> option, this specifies
the libvirt URI to use. The default is to use the default libvirt
connection.
+=item B<--csh>
+
+If using the I<--listen> option and a csh-like shell, use this option.
+See section L</REMOTE CONTROL AND CSH> below.
+
=item B<-d libvirt-domain> | B<--domain libvirt-domain>
Add disks from the named libvirt domain. If the I<--ro> option is
@@ -758,6 +763,13 @@ You can have several guestfish listener processes running using:
guestfish --remote=$pid1 cmd
guestfish --remote=$pid2 cmd
+=head2 REMOTE CONTROL AND CSH
+
+When using csh-like shells (csh, tcsh etc) you have to add the
+I<--csh> option:
+
+ eval `guestfish --listen --csh`
+
=head2 REMOTE CONTROL DETAILS
Remote control happens over a Unix domain socket called
diff --git a/fish/rc.c b/fish/rc.c
index 2d2f227..a2bde4a 100644
--- a/fish/rc.c
+++ b/fish/rc.c
@@ -198,7 +198,12 @@ rc_listen (void)
if (pid > 0) {
/* Parent process. */
- printf ("GUESTFISH_PID=%d; export GUESTFISH_PID\n", pid);
+
+ if (!remote_control_csh)
+ printf ("GUESTFISH_PID=%d; export GUESTFISH_PID\n", pid);
+ else
+ printf ("setenv GUESTFISH_PID %d\n", pid);
+
fflush (stdout);
_exit (0);
}
--
1.7.3.2
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