Add systemd-growfs tool

meson.build

@@ -1936,6 +1936,14 @@ executable('systemd-fsck',
            install : true,
            install_dir : rootlibexecdir)
 
+executable('systemd-growfs',
+           'src/partition/growfs.c',
+           include_directories : includes,
+           link_with : [libshared],
+           install_rpath : rootlibexecdir,
+           install : true,
+           install_dir : rootlibexecdir)
+
 executable('systemd-sleep',
            'src/sleep/sleep.c',
            include_directories : includes,

src/basic/missing.h

@@ -1271,4 +1271,8 @@ struct fib_rule_uid_range {
 #define AF_VSOCK 40
 #endif
 
+#ifndef EXT4_IOC_RESIZE_FS
+#  define EXT4_IOC_RESIZE_FS              _IOW('f', 16, __u64)
+#endif
+
 #include "missing_syscall.h"

src/partition/growfs.c

@@ -0,0 +1,156 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/***
+  This file is part of systemd.
+
+  Copyright 2017 Zbigniew Jędrzejewski-Szmek
+
+  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 <errno.h>
+#include <fcntl.h>
+#include <linux/magic.h>
+#include <sys/ioctl.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
+
+#include "device-nodes.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "format-util.h"
+#include "log.h"
+#include "missing.h"
+#include "mount-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "strv.h"
+
+static int resize_ext4(int mountfd, int devfd, uint64_t numblocks, uint64_t blocksize) {
+        assert((uint64_t) (int) blocksize == blocksize);
+
+        if (ioctl(mountfd, EXT4_IOC_RESIZE_FS, &numblocks) != 0)
+                return -errno;
+
+        return 0;
+}
+
+static int resize_btrfs(int mountfd, int devfd, uint64_t numblocks, uint64_t blocksize) {
+        struct btrfs_ioctl_vol_args args = {};
+        int r;
+
+        assert((uint64_t) (int) blocksize == blocksize);
+
+        r = snprintf(args.name, sizeof(args.name), "%"PRIu64, numblocks * blocksize);
+        /* The buffer is large enough for any number to fit... */
+        assert((size_t) r < sizeof(args.name));
+
+        if (ioctl(mountfd, BTRFS_IOC_RESIZE, &args) != 0)
+                return -errno;
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        dev_t devno;
+        _cleanup_close_ int mountfd = -1, devfd = -1;
+        int blocksize;
+        uint64_t size, numblocks;
+        char devpath[DEV_NUM_PATH_MAX], fb[FORMAT_BYTES_MAX];
+        struct statfs sfs;
+        int r;
+
+        if (argc != 2) {
+                log_error("This program requires one argument (the mountpoint).");
+                return EXIT_FAILURE;
+        }
+
+        log_set_target(LOG_TARGET_AUTO);
+        log_parse_environment();
+        log_open();
+
+        r = path_is_mount_point(argv[1], NULL, 0);
+        if (r < 0) {
+                log_error_errno(r, "Failed to check if \"%s\" is a mount point: %m", argv[1]);
+                return EXIT_FAILURE;
+        }
+        if (r == 0) {
+                log_error_errno(r, "\"%s\" is not a mount point: %m", argv[1]);
+                return EXIT_FAILURE;
+        }
+
+        r = get_block_device(argv[1], &devno);
+        if (r < 0) {
+                log_error_errno(r, "Failed to determine block device of \"%s\": %m", argv[1]);
+                return EXIT_FAILURE;
+        }
+
+        mountfd = open(argv[1], O_RDONLY|O_CLOEXEC);
+        if (mountfd < 0) {
+                log_error_errno(errno, "Failed to open \"%s\": %m", argv[1]);
+                return EXIT_FAILURE;
+        }
+
+        xsprintf_dev_num_path(devpath, "block", devno);
+        devfd = open(devpath, O_RDONLY|O_CLOEXEC);
+        if (devfd < 0) {
+                log_error_errno(errno, "Failed to open \"%s\": %m", devpath);
+                return EXIT_FAILURE;
+        }
+
+        if (ioctl(devfd, BLKBSZGET, &blocksize) != 0) {
+                log_error_errno(errno, "Failed to query block size of \"%s\": %m", devpath);
+                return EXIT_FAILURE;
+        }
+
+        if (ioctl(devfd, BLKGETSIZE64, &size) != 0) {
+                log_error_errno(errno, "Failed to query size of \"%s\": %m", devpath);
+                return EXIT_FAILURE;
+        }
+
+        if (size % blocksize != 0)
+                log_notice("Partition size %"PRIu64" is not a multiple of the blocksize %d,"
+                           " ignoring %"PRIu64" bytes", size, blocksize, size % blocksize);
+
+        numblocks = size / blocksize;
+
+        if (fstatfs(mountfd, &sfs) < 0) {
+                log_error_errno(errno, "Failed to stat file system \"%s\": %m", argv[1]);
+                return EXIT_FAILURE;
+        }
+
+        switch(sfs.f_type) {
+        case EXT4_SUPER_MAGIC:
+                r = resize_ext4(mountfd, devfd, numblocks, blocksize);
+                break;
+        case BTRFS_SUPER_MAGIC:
+                r = resize_btrfs(mountfd, devfd, numblocks, blocksize);
+                break;
+        default:
+                log_error("Don't know how to resize fs %llx on \"%s\"",
+                          (long long unsigned) sfs.f_type, argv[1]);
+                return EXIT_FAILURE;
+        }
+
+        if (r < 0) {
+                log_error_errno(r, "Failed to resize \"%s\" to %"PRIu64" blocks: %m",
+                                argv[1], numblocks);
+                return EXIT_FAILURE;
+        }
+
+        log_info("Successfully resized \"%s\" to %s bytes (%"PRIu64" blocks of %d bytes).",
+                 argv[1], format_bytes(fb, sizeof fb, size), numblocks, blocksize);
+        return EXIT_SUCCESS;
+}