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/* libguestfs - the guestfsd daemon
* Copyright (C) 2009-2012 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 <fcntl.h>
#include <limits.h>
#include <sys/types.h>
#include <dirent.h>
#include "cloexec.h"
#include "daemon.h"
#include "optgroups.h"
#include "actions.h"
/* On Windows, NAME_MAX is not defined. */
#ifndef NAME_MAX
#define NAME_MAX FILENAME_MAX
#endif
#ifdef HAVE_REALPATH
int
optgroup_realpath_available (void)
{
return 1;
}
char *
do_realpath (const char *path)
{
char *ret;
CHROOT_IN;
ret = realpath (path, NULL);
CHROOT_OUT;
if (ret == NULL) {
reply_with_perror ("%s", path);
return NULL;
}
return ret; /* caller frees */
}
#else /* !HAVE_REALPATH */
int
optgroup_realpath_available (void)
{
return 0;
}
char *
do_realpath (const char *path)
{
abort ();
}
#endif /* !HAVE_REALPATH */
static int find_path_element (int fd_cwd, int is_end, char *name, size_t *name_len_ret);
char *
do_case_sensitive_path (const char *path)
{
char ret[PATH_MAX+1] = "/";
char name[NAME_MAX+1];
size_t next = 1;
int fd_cwd, fd2, err, is_end;
size_t i;
char *retp;
/* 'fd_cwd' here is a surrogate for the current working directory, so
* that we don't have to actually call chdir(2).
*/
fd_cwd = open (sysroot, O_RDONLY|O_DIRECTORY|O_CLOEXEC);
if (fd_cwd == -1) {
reply_with_perror ("%s", sysroot);
return NULL;
}
/* First character is a '/'. Take each subsequent path element
* and follow it.
*/
while (*path) {
i = strcspn (path, "/");
if (i == 0) {
path++;
continue;
}
if ((i == 1 && path[0] == '.') ||
(i == 2 && path[0] == '.' && path[1] == '.')) {
reply_with_error ("path contained . or .. elements");
goto error;
}
if (i > NAME_MAX) {
reply_with_error ("path element too long");
goto error;
}
memcpy (name, path, i);
name[i] = '\0';
/* Skip to next element in path (for the next loop iteration). */
path += i;
is_end = *path == 0;
/* Read the current directory looking (case insensitively) for
* this element of the path. This replaces 'name' with the
* correct case version.
*/
if (find_path_element (fd_cwd, is_end, name, &i) == -1)
goto error;
/* Add the real name of this path element to the return value. */
if (next > 1)
ret[next++] = '/';
if (next + i >= PATH_MAX) {
reply_with_error ("final path too long");
goto error;
}
strcpy (&ret[next], name);
next += i;
/* Is it a directory? Try going into it. */
fd2 = openat (fd_cwd, name, O_RDONLY|O_DIRECTORY|O_CLOEXEC);
err = errno;
close (fd_cwd);
fd_cwd = fd2;
errno = err;
if (fd_cwd == -1) {
/* Some errors are OK provided we've reached the end of the path. */
if (is_end && (errno == ENOTDIR || errno == ENOENT))
break;
reply_with_perror ("openat: %s", name);
goto error;
}
}
if (fd_cwd >= 0)
close (fd_cwd);
ret[next] = '\0';
retp = strdup (ret);
if (retp == NULL) {
reply_with_perror ("strdup");
return NULL;
}
return retp; /* caller frees */
error:
if (fd_cwd >= 0)
close (fd_cwd);
return NULL;
}
/* 'fd_cwd' is a file descriptor pointing to an open directory.
* 'name' is a buffer of NAME_MAX+1 characters in size which initially
* contains the path element to search for. 'is_end' is a flag
* indicating if this is the last path element.
*
* We search the directory looking for a path element that case
* insensitively matches 'name' and update the 'name' buffer.
*
* If this is successful, return 0. If it fails, reply with an error
* and return -1.
*/
static int
find_path_element (int fd_cwd, int is_end, char *name, size_t *name_len_ret)
{
int fd2;
DIR *dir;
struct dirent *d;
fd2 = dup_cloexec (fd_cwd); /* because closedir will close it */
if (fd2 == -1) {
reply_with_perror ("dup");
return -1;
}
dir = fdopendir (fd2);
if (dir == NULL) {
reply_with_perror ("opendir");
close (fd2);
return -1;
}
for (;;) {
errno = 0;
d = readdir (dir);
if (d == NULL)
break;
if (STRCASEEQ (d->d_name, name))
break;
}
if (d == NULL && errno != 0) {
reply_with_perror ("readdir");
closedir (dir);
return -1;
}
if (d == NULL && is_end) {
/* Last path element: return it as-is, assuming that the user will
* create a new file or directory (RHBZ#840115).
*/
closedir (dir);
return 0;
}
if (d == NULL) {
reply_with_error ("%s: no file or directory found with this name", name);
closedir (dir);
return -1;
}
*name_len_ret = strlen (d->d_name);
if (*name_len_ret > NAME_MAX) {
/* Should never happen? */
reply_with_error ("path element longer than NAME_MAX");
closedir (dir);
return -1;
}
/* Safe because name is a buffer of NAME_MAX+1 characters. */
strcpy (name, d->d_name);
/* NB: closedir frees the structure associated with 'd', so we must
* do this last.
*/
if (closedir (dir) == -1) {
reply_with_perror ("closedir");
return -1;
}
return 0;
}
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