[Libguestfs] [PATCH v3] Allow 9p filesystems to be listed and mounted (RHBZ#714981).
Richard W.M. Jones
rjones at redhat.com
Wed Jun 22 14:33:18 UTC 2011
On Wed, Jun 22, 2011 at 03:04:02PM +0100, Daniel P. Berrange wrote:
> Is it possible to make 'options' the 3rd parameter, and optional,
> so you don't need todo
>
> ><fs> mount-9p "" org.kernel.other /tmp/
>
> Which is the common case.
It certainly is. Try the attached (first patch is identical to the
earlier version).
The syntax in guestfish is now:
mount-9p org.kernel.other /tmp
or:
mount-9p org.kernel.other /tmp options:ro
or you can quote the optional arg, but note that quotes have to go
around the whole string, eg:
mount-9p org.kernel.other /tmp "options:ro"
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming blog: http://rwmj.wordpress.com
Fedora now supports 80 OCaml packages (the OPEN alternative to F#)
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-------------- next part --------------
>From 5f10c3350338bbca735a74db26f98da968957bd9 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones at redhat.com>
Date: Wed, 22 Jun 2011 10:13:23 +0100
Subject: [PATCH 1/2] New API: list-9p lists 9p filesystem mount tags
(RHBZ#714981).
---
daemon/9p.c | 170 ++++++++++++++++++++++++++++++++++++++++
daemon/Makefile.am | 1 +
generator/generator_actions.ml | 7 ++
po/POTFILES.in | 1 +
src/MAX_PROC_NR | 2 +-
5 files changed, 180 insertions(+), 1 deletions(-)
create mode 100644 daemon/9p.c
diff --git a/daemon/9p.c b/daemon/9p.c
new file mode 100644
index 0000000..bc95803
--- /dev/null
+++ b/daemon/9p.c
@@ -0,0 +1,170 @@
+/* libguestfs - the guestfsd daemon
+ * Copyright (C) 2011 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <fcntl.h>
+
+#include "daemon.h"
+#include "actions.h"
+
+#define BUS_PATH "/sys/bus/virtio/drivers/9pnet_virtio"
+
+static char *read_whole_file (const char *filename);
+
+/* https://bugzilla.redhat.com/show_bug.cgi?id=714981#c1 */
+char **
+do_list_9p (void)
+{
+ char **r = NULL;
+ int size = 0, alloc = 0;
+
+ DIR *dir;
+ int err = 0;
+
+ dir = opendir (BUS_PATH);
+ if (!dir) {
+ perror ("opendir: " BUS_PATH);
+ if (errno != ENOENT)
+ return NULL;
+
+ /* If this directory doesn't exist, it probably means that
+ * the virtio driver isn't loaded. Don't return an error
+ * in this case, but return an empty list.
+ */
+ if (add_string (&r, &size, &alloc, NULL) == -1)
+ return NULL;
+
+ return r;
+ }
+
+ while (1) {
+ errno = 0;
+ struct dirent *d = readdir (dir);
+ if (d == NULL) break;
+
+ if (STRPREFIX (d->d_name, "virtio")) {
+ char mount_tag_path[256];
+ snprintf (mount_tag_path, sizeof mount_tag_path,
+ BUS_PATH "/%s/mount_tag", d->d_name);
+
+ /* A bit unclear, but it looks like the virtio transport allows
+ * the mount tag length to be unlimited (or up to 65536 bytes).
+ * See: linux/include/linux/virtio_9p.h
+ */
+ char *mount_tag = read_whole_file (mount_tag_path);
+ if (mount_tag == 0)
+ continue;
+
+ if (add_string (&r, &size, &alloc, mount_tag) == -1) {
+ free (mount_tag);
+ free_stringslen (r, size);
+ closedir (dir);
+ return NULL;
+ }
+
+ free (mount_tag);
+ }
+ }
+
+ /* Check readdir didn't fail */
+ if (errno != 0) {
+ reply_with_perror ("readdir: /sys/block");
+ free_stringslen (r, size);
+ closedir (dir);
+ return NULL;
+ }
+
+ /* Close the directory handle */
+ if (closedir (dir) == -1) {
+ reply_with_perror ("closedir: /sys/block");
+ free_stringslen (r, size);
+ return NULL;
+ }
+
+ /* Sort the tags. Note that r might be NULL if there are no tags. */
+ if (r != NULL)
+ sort_strings (r, size);
+
+ /* NULL terminate the list */
+ if (add_string (&r, &size, &alloc, NULL) == -1)
+ return NULL;
+
+ return r;
+}
+
+/* Read whole file into dynamically allocated array. If there is an
+ * error, DON'T call reply_with_perror, just return NULL. Returns a
+ * \0-terminated string.
+ */
+static char *
+read_whole_file (const char *filename)
+{
+ char *r = NULL;
+ size_t alloc = 0, size = 0;
+ int fd;
+
+ fd = open (filename, O_RDONLY);
+ if (fd == -1) {
+ perror (filename);
+ return NULL;
+ }
+
+ while (1) {
+ alloc += 256;
+ char *r2 = realloc (r, alloc);
+ if (r2 == NULL) {
+ perror ("realloc");
+ free (r);
+ return NULL;
+ }
+ r = r2;
+
+ /* The '- 1' in the size calculation ensures there is space below
+ * to add \0 to the end of the input.
+ */
+ ssize_t n = read (fd, r + size, alloc - size - 1);
+ if (n == -1) {
+ perror (filename);
+ free (r);
+ return NULL;
+ }
+ if (n == 0)
+ break;
+ size += n;
+ }
+
+ if (close (fd) == -1) {
+ perror (filename);
+ free (r);
+ return NULL;
+ }
+
+ r[size] = '\0';
+
+ return r;
+}
diff --git a/daemon/Makefile.am b/daemon/Makefile.am
index 8fb070f..78049c9 100644
--- a/daemon/Makefile.am
+++ b/daemon/Makefile.am
@@ -88,6 +88,7 @@ errnostring.h: $(libsrcdir)/errnostring.h
noinst_PROGRAMS = guestfsd
guestfsd_SOURCES = \
+ 9p.c \
actions.h \
available.c \
augeas.c \
diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml
index 74b6515..634ceeb 100644
--- a/generator/generator_actions.ml
+++ b/generator/generator_actions.ml
@@ -5960,6 +5960,13 @@ This returns true iff the device exists and contains all zero bytes.
Note that for large devices this can take a long time to run.");
+ ("list_9p", (RStringList "mounttags", [], []), 285, [],
+ [],
+ "list 9p filesystems",
+ "\
+List all 9p filesystems attached to the guest. A list of
+mount tags is returned.");
+
]
let all_functions = non_daemon_functions @ daemon_functions
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 7c0df52..da47c91 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -1,6 +1,7 @@
cat/virt-cat.c
cat/virt-filesystems.c
cat/virt-ls.c
+daemon/9p.c
daemon/augeas.c
daemon/available.c
daemon/base64.c
diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index c9716b7..6cf4452 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-284
+285
--
1.7.5.2
-------------- next part --------------
>From 14bb3b5ae75f41af05ca6d26ebbb5e85aacf2e20 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones at redhat.com>
Date: Wed, 22 Jun 2011 13:55:14 +0100
Subject: [PATCH 2/2] New API: mount-9p lets you mount 9p filesystems
(RHBZ#714981).
The updated patch makes 'options' into an optional parameter.
---
daemon/9p.c | 57 ++++++++++++++++++++++++++++++++++++++++
generator/generator_actions.ml | 11 +++++++
src/MAX_PROC_NR | 2 +-
3 files changed, 69 insertions(+), 1 deletions(-)
diff --git a/daemon/9p.c b/daemon/9p.c
index bc95803..9e89e08 100644
--- a/daemon/9p.c
+++ b/daemon/9p.c
@@ -168,3 +168,60 @@ read_whole_file (const char *filename)
return r;
}
+
+/* Takes optional arguments, consult optargs_bitmask. */
+int
+do_mount_9p (const char *mount_tag, const char *mountpoint, const char *options)
+{
+ char *mp = NULL, *opts = NULL, *err = NULL;
+ struct stat statbuf;
+ int r = -1;
+
+ ABS_PATH (mountpoint, , return -1);
+
+ mp = sysroot_path (mountpoint);
+ if (!mp) {
+ reply_with_perror ("malloc");
+ goto out;
+ }
+
+ /* Check the mountpoint exists and is a directory. */
+ if (stat (mp, &statbuf) == -1) {
+ reply_with_perror ("%s", mountpoint);
+ goto out;
+ }
+ if (!S_ISDIR (statbuf.st_mode)) {
+ reply_with_perror ("%s: mount point is not a directory", mountpoint);
+ goto out;
+ }
+
+ /* Add trans=virtio to the options. */
+ if ((optargs_bitmask & GUESTFS_MOUNT_9P_OPTIONS_BITMASK) &&
+ STRNEQ (options, "")) {
+ if (asprintf (&opts, "trans=virtio,%s", options) == -1) {
+ reply_with_perror ("asprintf");
+ goto out;
+ }
+ }
+ else {
+ opts = strdup ("trans=virtio");
+ if (opts == NULL) {
+ reply_with_perror ("strdup");
+ goto out;
+ }
+ }
+
+ r = command (NULL, &err,
+ "mount", "-o", opts, "-t", "9p", mount_tag, mp, NULL);
+ if (r == -1) {
+ reply_with_error ("%s on %s: %s", mount_tag, mountpoint, err);
+ goto out;
+ }
+
+ r = 0;
+ out:
+ free (err);
+ free (opts);
+ free (mp);
+ return r;
+}
diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml
index 634ceeb..9130034 100644
--- a/generator/generator_actions.ml
+++ b/generator/generator_actions.ml
@@ -5967,6 +5967,17 @@ Note that for large devices this can take a long time to run.");
List all 9p filesystems attached to the guest. A list of
mount tags is returned.");
+ ("mount_9p", (RErr, [String "mounttag"; String "mountpoint"], [String "options"]), 286, [],
+ [],
+ "mount 9p filesystem",
+ "\
+Mount the virtio-9p filesystem with the tag C<mounttag> on the
+directory C<mountpoint>.
+
+If required, C<trans=virtio> will be automatically added to the options.
+Any other options required can be passed in the optional C<options>
+parameter.");
+
]
let all_functions = non_daemon_functions @ daemon_functions
diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index 6cf4452..c20f657 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-285
+286
--
1.7.5.2
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