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/* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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);
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;
}
/* 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;
}
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