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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <sched.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <unistd.h>
#include "alloc-util.h"
#include "btrfs-util.h"
#include "capability-util.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "import-common.h"
#include "os-util.h"
#include "process-util.h"
#include "signal-util.h"
#include "tmpfile-util.h"
#include "util.h"
int import_make_read_only_fd(int fd) {
int r;
assert(fd >= 0);
/* First, let's make this a read-only subvolume if it refers
* to a subvolume */
r = btrfs_subvol_set_read_only_fd(fd, true);
if (IN_SET(r, -ENOTTY, -ENOTDIR, -EINVAL)) {
struct stat st;
/* This doesn't refer to a subvolume, or the file
* system isn't even btrfs. In that, case fall back to
* chmod()ing */
r = fstat(fd, &st);
if (r < 0)
return log_error_errno(errno, "Failed to stat temporary image: %m");
/* Drop "w" flag */
if (fchmod(fd, st.st_mode & 07555) < 0)
return log_error_errno(errno, "Failed to chmod() final image: %m");
return 0;
} else if (r < 0)
return log_error_errno(r, "Failed to make subvolume read-only: %m");
return 0;
}
int import_make_read_only(const char *path) {
_cleanup_close_ int fd = 1;
fd = open(path, O_RDONLY|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return log_error_errno(errno, "Failed to open %s: %m", path);
return import_make_read_only_fd(fd);
}
int import_fork_tar_x(const char *path, pid_t *ret) {
_cleanup_close_pair_ int pipefd[2] = { -1, -1 };
pid_t pid;
int r;
assert(path);
assert(ret);
if (pipe2(pipefd, O_CLOEXEC) < 0)
return log_error_errno(errno, "Failed to create pipe for tar: %m");
r = safe_fork("(tar)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
if (r < 0)
return r;
if (r == 0) {
uint64_t retain =
(1ULL << CAP_CHOWN) |
(1ULL << CAP_FOWNER) |
(1ULL << CAP_FSETID) |
(1ULL << CAP_MKNOD) |
(1ULL << CAP_SETFCAP) |
(1ULL << CAP_DAC_OVERRIDE);
/* Child */
pipefd[1] = safe_close(pipefd[1]);
r = rearrange_stdio(pipefd[0], -1, STDERR_FILENO);
if (r < 0) {
log_error_errno(r, "Failed to rearrange stdin/stdout: %m");
_exit(EXIT_FAILURE);
}
if (unshare(CLONE_NEWNET) < 0)
log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m");
r = capability_bounding_set_drop(retain, true);
if (r < 0)
log_error_errno(r, "Failed to drop capabilities, ignoring: %m");
execlp("tar", "tar", "--numeric-owner", "-C", path, "-px", "--xattrs", "--xattrs-include=*", NULL);
log_error_errno(errno, "Failed to execute tar: %m");
_exit(EXIT_FAILURE);
}
*ret = pid;
return TAKE_FD(pipefd[1]);
}
int import_fork_tar_c(const char *path, pid_t *ret) {
_cleanup_close_pair_ int pipefd[2] = { -1, -1 };
pid_t pid;
int r;
assert(path);
assert(ret);
if (pipe2(pipefd, O_CLOEXEC) < 0)
return log_error_errno(errno, "Failed to create pipe for tar: %m");
r = safe_fork("(tar)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
if (r < 0)
return r;
if (r == 0) {
uint64_t retain = (1ULL << CAP_DAC_OVERRIDE);
/* Child */
pipefd[0] = safe_close(pipefd[0]);
r = rearrange_stdio(-1, pipefd[1], STDERR_FILENO);
if (r < 0) {
log_error_errno(r, "Failed to rearrange stdin/stdout: %m");
_exit(EXIT_FAILURE);
}
if (unshare(CLONE_NEWNET) < 0)
log_error_errno(errno, "Failed to lock tar into network namespace, ignoring: %m");
r = capability_bounding_set_drop(retain, true);
if (r < 0)
log_error_errno(r, "Failed to drop capabilities, ignoring: %m");
execlp("tar", "tar", "-C", path, "-c", "--xattrs", "--xattrs-include=*", ".", NULL);
log_error_errno(errno, "Failed to execute tar: %m");
_exit(EXIT_FAILURE);
}
*ret = pid;
return TAKE_FD(pipefd[0]);
}
int import_mangle_os_tree(const char *path) {
_cleanup_closedir_ DIR *d = NULL, *cd = NULL;
_cleanup_free_ char *child = NULL, *t = NULL;
const char *joined;
struct dirent *de;
int r;
assert(path);
/* Some tarballs contain a single top-level directory that contains the actual OS directory tree. Try to
* recognize this, and move the tree one level up. */
r = path_is_os_tree(path);
if (r < 0)
return log_error_errno(r, "Failed to determine whether '%s' is an OS tree: %m", path);
if (r > 0) {
log_debug("Directory tree '%s' is a valid OS tree.", path);
return 0;
}
log_debug("Directory tree '%s' is not recognizable as OS tree, checking whether to rearrange it.", path);
d = opendir(path);
if (!d)
return log_error_errno(r, "Failed to open directory '%s': %m", path);
errno = 0;
de = readdir_no_dot(d);
if (!de) {
if (errno != 0)
return log_error_errno(errno, "Failed to iterate through directory '%s': %m", path);
log_debug("Directory '%s' is empty, leaving it as it is.", path);
return 0;
}
child = strdup(de->d_name);
if (!child)
return log_oom();
errno = 0;
de = readdir_no_dot(d);
if (de) {
if (errno != 0)
return log_error_errno(errno, "Failed to iterate through directory '%s': %m", path);
log_debug("Directory '%s' does not look like a directory tree, and has multiple children, leaving as it is.", path);
return 0;
}
joined = strjoina(path, "/", child);
r = path_is_os_tree(joined);
if (r == -ENOTDIR) {
log_debug("Directory '%s' does not look like a directory tree, and contains a single regular file only, leaving as it is.", path);
return 0;
}
if (r < 0)
return log_error_errno(r, "Failed to determine whether '%s' is an OS tree: %m", joined);
if (r == 0) {
log_debug("Neither '%s' nor '%s' is a valid OS tree, leaving them as they are.", path, joined);
return 0;
}
/* Nice, we have checked now:
*
* 1. The top-level directory does not qualify as OS tree
* 1. The top-level directory only contains one item
* 2. That item is a directory
* 3. And that directory qualifies as OS tree
*
* Let's now rearrange things, moving everything in the inner directory one level up */
cd = xopendirat(dirfd(d), child, O_NOFOLLOW);
if (!cd)
return log_error_errno(errno, "Can't open directory '%s': %m", joined);
log_info("Rearranging '%s', moving OS tree one directory up.", joined);
/* Let's rename the child to an unguessable name so that we can be sure all files contained in it can be
* safely moved up and won't collide with the name. */
r = tempfn_random(child, NULL, &t);
if (r < 0)
return log_oom();
r = rename_noreplace(dirfd(d), child, dirfd(d), t);
if (r < 0)
return log_error_errno(r, "Unable to rename '%s' to '%s/%s': %m", joined, path, t);
FOREACH_DIRENT_ALL(de, cd, return log_error_errno(errno, "Failed to iterate through directory '%s': %m", joined)) {
if (dot_or_dot_dot(de->d_name))
continue;
r = rename_noreplace(dirfd(cd), de->d_name, dirfd(d), de->d_name);
if (r < 0)
return log_error_errno(r, "Unable to move '%s/%s/%s' to '%s/%s': %m", path, t, de->d_name, path, de->d_name);
}
if (unlinkat(dirfd(d), t, AT_REMOVEDIR) < 0)
return log_error_errno(errno, "Failed to remove temporary directory '%s/%s': %m", path, t);
log_info("Successfully rearranged OS tree.");
return 0;
}
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