summaryrefslogtreecommitdiff
path: root/src/import/import-common.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/import/import-common.c')
-rw-r--r--src/import/import-common.c150
1 files changed, 150 insertions, 0 deletions
diff --git a/src/import/import-common.c b/src/import/import-common.c
new file mode 100644
index 0000000000..6c3f347e75
--- /dev/null
+++ b/src/import/import-common.c
@@ -0,0 +1,150 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2015 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/prctl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "util.h"
+#include "btrfs-util.h"
+#include "capability.h"
+#include "import-common.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 (r == -ENOTTY || r == -ENOTDIR || r == -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(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");
+
+ pid = fork();
+ if (pid < 0)
+ return log_error_errno(errno, "Failed to fork off tar: %m");
+
+ if (pid == 0) {
+ int null_fd;
+ uint64_t retain =
+ (1ULL << CAP_CHOWN) |
+ (1ULL << CAP_FOWNER) |
+ (1ULL << CAP_FSETID) |
+ (1ULL << CAP_MKNOD) |
+ (1ULL << CAP_SETFCAP) |
+ (1ULL << CAP_DAC_OVERRIDE);
+
+ /* Child */
+
+ reset_all_signal_handlers();
+ reset_signal_mask();
+ assert_se(prctl(PR_SET_PDEATHSIG, SIGTERM) == 0);
+
+ pipefd[1] = safe_close(pipefd[1]);
+
+ if (dup2(pipefd[0], STDIN_FILENO) != STDIN_FILENO) {
+ log_error_errno(errno, "Failed to dup2() fd: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (pipefd[0] != STDIN_FILENO)
+ pipefd[0] = safe_close(pipefd[0]);
+
+ null_fd = open("/dev/null", O_WRONLY|O_NOCTTY);
+ if (null_fd < 0) {
+ log_error_errno(errno, "Failed to open /dev/null: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (dup2(null_fd, STDOUT_FILENO) != STDOUT_FILENO) {
+ log_error_errno(errno, "Failed to dup2() fd: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (null_fd != STDOUT_FILENO)
+ null_fd = safe_close(null_fd);
+
+ fd_cloexec(STDIN_FILENO, false);
+ fd_cloexec(STDOUT_FILENO, false);
+ fd_cloexec(STDERR_FILENO, false);
+
+ 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", NULL);
+ log_error_errno(errno, "Failed to execute tar: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ pipefd[0] = safe_close(pipefd[0]);
+ r = pipefd[1];
+ pipefd[1] = -1;
+
+ *ret = pid;
+
+ return r;
+}