/**
* Copy in @result the equivalent of "@tracee->root + canon(@dir_fd +
* @user_path)". If @user_path is not absolute then it is relative to
* the directory referred by the descriptor @dir_fd (AT_FDCWD is for
* the current working directory). See the documentation of
* canonicalize() for the meaning of @deref_final. This function
* returns -errno if an error occured, otherwise 0.
*/
int translate_path(Tracee *tracee, char result[PATH_MAX], int dir_fd,
const char *user_path, bool deref_final)
{
char guest_path[PATH_MAX];
int status;
/* Use "/" as the base if it is an absolute guest path. */
if (user_path[0] == '/') {
strcpy(result, "/");
}
/* It is relative to a directory referred by a descriptor, see
* openat(2) for details. */
else if (dir_fd != AT_FDCWD) {
/* /proc/@tracee->pid/fd/@dir_fd -> result. */
status = readlink_proc_pid_fd(tracee->pid, dir_fd, result);
if (status < 0)
return status;
/* Named file descriptors may reference special
* objects like pipes, sockets, inodes, ... Such
* objects do not belong to the file-system. */
if (result[0] != '/')
return -ENOTDIR;
/* Remove the leading "root" part of the base
* (required!). */
status = detranslate_path(tracee, result, NULL);
if (status < 0)
return status;
}
/* It is relative to the current working directory. */
else {
status = getcwd2(tracee, result);
if (status < 0)
return status;
}
VERBOSE(tracee, 2, "pid %d: translate(\"%s\" + \"%s\")",
tracee != NULL ? tracee->pid : 0, result, user_path);
status = notify_extensions(tracee, GUEST_PATH, (intptr_t) result, (intptr_t) user_path);
if (status < 0)
return status;
if (status > 0)
goto skip;
/* So far "result" was used as a base path, it's time to join
* it to the user path. */
assert(result[0] == '/');
status = join_paths(2, guest_path, result, user_path);
if (status < 0)
return status;
strcpy(result, "/");
/* Canonicalize regarding the new root. */
status = canonicalize(tracee, guest_path, deref_final, result, 0);
if (status < 0)
return status;
/* Final binding substitution to convert "result" into a host
* path, since canonicalize() works from the guest
* point-of-view. */
status = substitute_binding(tracee, GUEST, result);
if (status < 0)
return status;
skip:
VERBOSE(tracee, 2, "pid %d: -> \"%s\"",
tracee != NULL ? tracee->pid : 0, result);
return 0;
}
/**
* Copy in @host_path the equivalent of "@tracee->root +
* canonicalize(@dir_fd + @guest_path)". If @guest_path is not
* absolute then it is relative to the directory referred by the
* descriptor @dir_fd (AT_FDCWD is for the current working directory).
* See the documentation of canonicalize() for the meaning of
* @deref_final. This function returns -errno if an error occured,
* otherwise 0.
*/
int translate_path(Tracee *tracee, char host_path[PATH_MAX],
int dir_fd, const char *guest_path, bool deref_final)
{
int status;
/* Use "/" as the base if it is an absolute guest path. */
if (guest_path[0] == '/') {
strcpy(host_path, "/");
}
/* It is relative to the current working directory or to a
* directory referred by a descriptors, see openat(2) for
* details. */
else if (dir_fd == AT_FDCWD) {
status = getcwd2(tracee, host_path);
if (status < 0)
return status;
}
else {
struct stat statl;
/* /proc/@tracee->pid/fd/@dir_fd -> host_path. */
status = readlink_proc_pid_fd(tracee->pid, dir_fd, host_path);
if (status < 0)
return status;
/* Ensure it points to a directory. */
status = stat(host_path, &statl);
if (status < 0)
return -errno;
if (!S_ISDIR(statl.st_mode))
return -ENOTDIR;
/* Remove the leading "root" part of the base
* (required!). */
status = detranslate_path(tracee, host_path, NULL);
if (status < 0)
return status;
}
VERBOSE(tracee, 2, "pid %d: translate(\"%s\" + \"%s\")",
tracee != NULL ? tracee->pid : 0, host_path, guest_path);
status = notify_extensions(tracee, GUEST_PATH, (intptr_t)host_path, (intptr_t)guest_path);
if (status < 0)
return status;
if (status > 0)
goto skip;
/* Canonicalize regarding the new root. */
status = canonicalize(tracee, guest_path, deref_final, host_path, 0);
if (status < 0)
return status;
/* Final binding substitution to convert "host_path" into a host
* path, since canonicalize() works from the guest
* point-of-view. */
status = substitute_binding(tracee, GUEST, host_path);
if (status < 0)
return status;
skip:
VERBOSE(tracee, 2, "pid %d: -> \"%s\"",
tracee != NULL ? tracee->pid : 0, host_path);
return 0;
}
