diff options
Diffstat (limited to 'src/import/import-common.c')
| -rw-r--r-- | src/import/import-common.c | 150 |
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; +} |