From: David Howells <dhowells@redhat.com>
To: viro@zeniv.linux.org.uk
Cc: dhowells@redhat.com, raven@themaw.net, mszeredi@redhat.com,
christian@brauner.io, jannh@google.com, darrick.wong@oracle.com,
linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 11/17] fsinfo: sample: Mount listing program [ver #17]
Date: Fri, 21 Feb 2020 18:03:16 +0000 [thread overview]
Message-ID: <158230819662.2185128.7616577805802640363.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <158230810644.2185128.16726948836367716086.stgit@warthog.procyon.org.uk>
Implement a program to demonstrate mount listing using the new fsinfo()
syscall, for example:
# ./test-mntinfo -M 21
MOUNT MOUNT ID CHANGE# TYPE & DEVICE
------------------------------------- ---------- ---------- ---------------
21 21 8 sysfs 0:15
\_ kernel/security 24 0 securityfs 0:8
\_ fs/cgroup 28 16 tmpfs 0:19
| \_ unified 29 0 cgroup2 0:1a
| \_ systemd 30 0 cgroup 0:1b
| \_ freezer 34 0 cgroup 0:1f
| \_ cpu,cpuacct 35 0 cgroup 0:20
| \_ devices 36 0 cgroup 0:21
| \_ memory 37 0 cgroup 0:22
| \_ cpuset 38 0 cgroup 0:23
| \_ net_cls,net_prio 39 0 cgroup 0:24
| \_ hugetlb 40 0 cgroup 0:25
| \_ rdma 41 0 cgroup 0:26
| \_ blkio 42 0 cgroup 0:27
| \_ perf_event 43 0 cgroup 0:28
\_ fs/pstore 31 0 pstore 0:1c
\_ firmware/efi/efivars 32 0 efivarfs 0:1d
\_ fs/bpf 33 0 bpf 0:1e
\_ kernel/config 92 0 configfs 0:10
\_ fs/selinux 44 0 selinuxfs 0:12
\_ kernel/debug 48 0 debugfs 0:7
Signed-off-by: David Howells <dhowells@redhat.com>
---
samples/vfs/Makefile | 2
samples/vfs/test-mntinfo.c | 243 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 245 insertions(+)
create mode 100644 samples/vfs/test-mntinfo.c
diff --git a/samples/vfs/Makefile b/samples/vfs/Makefile
index 9159ad1d7fc5..19be60ab950e 100644
--- a/samples/vfs/Makefile
+++ b/samples/vfs/Makefile
@@ -4,12 +4,14 @@
hostprogs := \
test-fsinfo \
test-fsmount \
+ test-mntinfo \
test-statx
always-y := $(hostprogs)
HOSTCFLAGS_test-fsinfo.o += -I$(objtree)/usr/include
HOSTLDLIBS_test-fsinfo += -static -lm
+HOSTCFLAGS_test-mntinfo.o += -I$(objtree)/usr/include
HOSTCFLAGS_test-fsmount.o += -I$(objtree)/usr/include
HOSTCFLAGS_test-statx.o += -I$(objtree)/usr/include
diff --git a/samples/vfs/test-mntinfo.c b/samples/vfs/test-mntinfo.c
new file mode 100644
index 000000000000..f4d90d0671c5
--- /dev/null
+++ b/samples/vfs/test-mntinfo.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Test the fsinfo() system call
+ *
+ * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define _GNU_SOURCE
+#define _ATFILE_SOURCE
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <errno.h>
+#include <time.h>
+#include <math.h>
+#include <sys/syscall.h>
+#include <linux/fsinfo.h>
+#include <linux/socket.h>
+#include <linux/fcntl.h>
+#include <sys/stat.h>
+#include <arpa/inet.h>
+
+#ifndef __NR_fsinfo
+#define __NR_fsinfo -1
+#endif
+
+static __attribute__((unused))
+ssize_t fsinfo(int dfd, const char *filename, struct fsinfo_params *params,
+ void *buffer, size_t buf_size)
+{
+ return syscall(__NR_fsinfo, dfd, filename, params, buffer, buf_size);
+}
+
+static char tree_buf[4096];
+static char bar_buf[4096];
+
+/*
+ * Get an fsinfo attribute in a statically allocated buffer.
+ */
+static void get_attr(unsigned int mnt_id, unsigned int attr,
+ void *buf, size_t buf_size)
+{
+ struct fsinfo_params params = {
+ .flags = FSINFO_FLAGS_QUERY_MOUNT,
+ .request = attr,
+ };
+ char file[32];
+ long ret;
+
+ sprintf(file, "%u", mnt_id);
+
+ memset(buf, 0xbd, buf_size);
+
+ ret = fsinfo(AT_FDCWD, file, ¶ms, buf, buf_size);
+ if (ret == -1) {
+ fprintf(stderr, "mount-%s: %m\n", file);
+ exit(1);
+ }
+}
+
+/*
+ * Get an fsinfo attribute in a dynamically allocated buffer.
+ */
+static void *get_attr_alloc(unsigned int mnt_id, unsigned int attr,
+ unsigned int Nth, size_t *_size)
+{
+ struct fsinfo_params params = {
+ .flags = FSINFO_FLAGS_QUERY_MOUNT,
+ .request = attr,
+ .Nth = Nth,
+ };
+ size_t buf_size = 4096;
+ char file[32];
+ void *r;
+ long ret;
+
+ sprintf(file, "%u", mnt_id);
+
+ for (;;) {
+ r = malloc(buf_size);
+ if (!r) {
+ perror("malloc");
+ exit(1);
+ }
+ memset(r, 0xbd, buf_size);
+
+ ret = fsinfo(AT_FDCWD, file, ¶ms, r, buf_size);
+ if (ret == -1) {
+ fprintf(stderr, "mount-%s: %x,%x,%x %m\n",
+ file, params.request, params.Nth, params.Mth);
+ exit(1);
+ }
+
+ if (ret <= buf_size) {
+ *_size = ret;
+ break;
+ }
+ buf_size = (ret + 4096 - 1) & ~(4096 - 1);
+ }
+
+ return r;
+}
+
+/*
+ * Display a mount and then recurse through its children.
+ */
+static void display_mount(unsigned int mnt_id, unsigned int depth, char *path)
+{
+ struct fsinfo_mount_child *children;
+ struct fsinfo_mount_info info;
+ struct fsinfo_ids ids;
+ unsigned int d;
+ size_t ch_size, p_size;
+ char dev[64];
+ int i, n, s;
+
+ get_attr(mnt_id, FSINFO_ATTR_MOUNT_INFO, &info, sizeof(info));
+ get_attr(mnt_id, FSINFO_ATTR_IDS, &ids, sizeof(ids));
+ if (depth > 0)
+ printf("%s", tree_buf);
+
+ s = strlen(path);
+ printf("%s", !s ? "\"\"" : path);
+ if (!s)
+ s += 2;
+ s += depth;
+ if (s < 38)
+ s = 38 - s;
+ else
+ s = 1;
+ printf("%*.*s", s, s, "");
+
+ sprintf(dev, "%x:%x", ids.f_dev_major, ids.f_dev_minor);
+ printf("%10u %8x %2x %5s %s",
+ info.mnt_id, info.change_counter,
+ info.attr,
+ dev, ids.f_fs_name);
+ putchar('\n');
+
+ children = get_attr_alloc(mnt_id, FSINFO_ATTR_MOUNT_CHILDREN, 0, &ch_size);
+ n = ch_size / sizeof(children[0]) - 1;
+
+ bar_buf[depth + 1] = '|';
+ if (depth > 0) {
+ tree_buf[depth - 4 + 1] = bar_buf[depth - 4 + 1];
+ tree_buf[depth - 4 + 2] = ' ';
+ }
+
+ tree_buf[depth + 0] = ' ';
+ tree_buf[depth + 1] = '\\';
+ tree_buf[depth + 2] = '_';
+ tree_buf[depth + 3] = ' ';
+ tree_buf[depth + 4] = 0;
+ d = depth + 4;
+
+ for (i = 0; i < n; i++) {
+ if (i == n - 1)
+ bar_buf[depth + 1] = ' ';
+ path = get_attr_alloc(children[i].mnt_id, FSINFO_ATTR_MOUNT_POINT,
+ 0, &p_size);
+ display_mount(children[i].mnt_id, d, path + 1);
+ free(path);
+ }
+
+ free(children);
+ if (depth > 0) {
+ tree_buf[depth - 4 + 1] = '\\';
+ tree_buf[depth - 4 + 2] = '_';
+ }
+ tree_buf[depth] = 0;
+}
+
+/*
+ * Find the ID of whatever is at the nominated path.
+ */
+static unsigned int lookup_mnt_by_path(const char *path)
+{
+ struct fsinfo_mount_info mnt;
+ struct fsinfo_params params = {
+ .flags = FSINFO_FLAGS_QUERY_PATH,
+ .request = FSINFO_ATTR_MOUNT_INFO,
+ };
+
+ if (fsinfo(AT_FDCWD, path, ¶ms, &mnt, sizeof(mnt)) == -1) {
+ perror(path);
+ exit(1);
+ }
+
+ return mnt.mnt_id;
+}
+
+/*
+ *
+ */
+int main(int argc, char **argv)
+{
+ unsigned int mnt_id;
+ char *path;
+ bool use_mnt_id = false;
+ int opt;
+
+ while ((opt = getopt(argc, argv, "M"))) {
+ switch (opt) {
+ case 'M':
+ use_mnt_id = true;
+ continue;
+ }
+ break;
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ switch (argc) {
+ case 0:
+ mnt_id = lookup_mnt_by_path("/");
+ path = "ROOT";
+ break;
+ case 1:
+ path = argv[0];
+ if (use_mnt_id) {
+ mnt_id = strtoul(argv[0], NULL, 0);
+ break;
+ }
+
+ mnt_id = lookup_mnt_by_path(argv[0]);
+ break;
+ default:
+ printf("Format: test-mntinfo\n");
+ printf("Format: test-mntinfo <path>\n");
+ printf("Format: test-mntinfo -M <mnt_id>\n");
+ exit(2);
+ }
+
+ printf("MOUNT MOUNT ID CHANGE# AT DEV TYPE\n");
+ printf("------------------------------------- ---------- -------- -- ----- --------\n");
+ display_mount(mnt_id, 0, path);
+ return 0;
+}
next prev parent reply other threads:[~2020-02-21 18:03 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 18:01 [PATCH 00/17] VFS: Filesystem information and notifications [ver #17] David Howells
2020-02-21 18:01 ` [PATCH 01/17] watch_queue: Add security hooks to rule on setting mount and sb watches " David Howells
2020-02-21 18:02 ` [PATCH 02/17] watch_queue: Implement mount topology and attribute change notifications " David Howells
2020-02-21 18:02 ` [PATCH 03/17] watch_queue: sample: Display mount tree " David Howells
2020-02-21 18:02 ` [PATCH 04/17] watch_queue: Introduce a non-repeating system-unique superblock ID " David Howells
2020-02-21 18:02 ` [PATCH 05/17] watch_queue: Add superblock notifications " David Howells
2020-02-21 18:02 ` [PATCH 06/17] watch_queue: sample: Display " David Howells
2020-02-21 18:02 ` [PATCH 07/17] fsinfo: Add fsinfo() syscall to query filesystem information " David Howells
2020-02-26 2:29 ` Aleksa Sarai
2020-02-28 14:44 ` David Howells
2020-02-21 18:02 ` [PATCH 08/17] fsinfo: Provide a bitmap of supported features " David Howells
2020-02-21 18:03 ` [PATCH 09/17] fsinfo: Allow fsinfo() to look up a mount object by ID " David Howells
2020-02-21 18:03 ` [PATCH 10/17] fsinfo: Allow mount information to be queried " David Howells
2020-03-04 14:58 ` Miklos Szeredi
2020-03-04 16:10 ` Miklos Szeredi
2020-02-21 18:03 ` David Howells [this message]
2020-02-21 18:03 ` [PATCH 12/17] fsinfo: Allow the mount topology propogation flags to be retrieved " David Howells
2020-02-21 18:03 ` [PATCH 13/17] fsinfo: Query superblock unique ID and notification counter " David Howells
2020-02-21 18:03 ` [PATCH 14/17] fsinfo: Add API documentation " David Howells
2020-02-21 18:03 ` [PATCH 15/17] fsinfo: Add support for AFS " David Howells
2020-02-21 18:03 ` [PATCH 16/17] fsinfo: Add example support for Ext4 " David Howells
2020-02-21 18:04 ` [PATCH 17/17] fsinfo: Add example support for NFS " David Howells
2020-02-21 20:21 ` [PATCH 00/17] VFS: Filesystem information and notifications " James Bottomley
2020-02-24 10:24 ` Miklos Szeredi
2020-02-24 14:55 ` James Bottomley
2020-02-24 15:28 ` Miklos Szeredi
2020-02-25 12:13 ` Steven Whitehouse
2020-02-25 15:28 ` James Bottomley
2020-02-25 15:47 ` Steven Whitehouse
2020-02-26 9:11 ` Miklos Szeredi
2020-02-26 10:51 ` Steven Whitehouse
2020-02-27 5:06 ` Ian Kent
2020-02-27 9:36 ` Miklos Szeredi
2020-02-27 11:34 ` Ian Kent
2020-02-27 13:45 ` Miklos Szeredi
2020-02-27 15:14 ` Karel Zak
2020-02-28 0:43 ` Ian Kent
2020-02-28 8:35 ` Miklos Szeredi
2020-02-28 12:27 ` Greg Kroah-Hartman
2020-02-28 16:24 ` Miklos Szeredi
2020-02-28 17:15 ` Al Viro
2020-03-02 8:43 ` Miklos Szeredi
2020-03-02 10:34 ` Karel Zak
2020-02-28 16:42 ` David Howells
2020-02-28 15:08 ` James Bottomley
2020-02-28 15:40 ` Miklos Szeredi
2020-02-28 0:12 ` Ian Kent
2020-02-28 15:52 ` Christian Brauner
2020-02-28 16:36 ` David Howells
2020-03-02 9:09 ` Miklos Szeredi
2020-03-02 9:38 ` Greg Kroah-Hartman
2020-03-03 5:27 ` Ian Kent
2020-03-03 7:46 ` Miklos Szeredi
2020-03-06 16:25 ` Miklos Szeredi
2020-03-06 19:43 ` Al Viro
2020-03-06 19:54 ` Miklos Szeredi
2020-03-06 19:58 ` Al Viro
2020-03-06 20:05 ` Al Viro
2020-03-06 20:11 ` Miklos Szeredi
2020-03-06 20:37 ` Al Viro
2020-03-06 20:38 ` Al Viro
2020-03-06 20:45 ` Al Viro
2020-03-06 20:49 ` Al Viro
2020-03-06 20:51 ` Miklos Szeredi
2020-03-06 21:28 ` Al Viro
2020-03-06 20:56 ` Al Viro
2020-03-06 20:51 ` Miklos Szeredi
2020-03-07 9:48 ` Greg Kroah-Hartman
2020-03-07 20:48 ` Miklos Szeredi
2020-03-03 9:12 ` David Howells
2020-03-03 9:26 ` Miklos Szeredi
2020-03-03 9:48 ` Miklos Szeredi
2020-03-03 10:21 ` Steven Whitehouse
2020-03-03 10:32 ` Miklos Szeredi
2020-03-03 11:09 ` Ian Kent
2020-03-03 10:00 ` Christian Brauner
2020-03-03 10:13 ` Miklos Szeredi
2020-03-03 10:25 ` Christian Brauner
2020-03-03 11:33 ` Miklos Szeredi
2020-03-03 11:56 ` Christian Brauner
2020-03-03 11:38 ` Karel Zak
2020-03-03 13:03 ` Greg Kroah-Hartman
2020-03-03 13:14 ` Greg Kroah-Hartman
2020-03-03 13:34 ` Miklos Szeredi
2020-03-03 13:43 ` Greg Kroah-Hartman
2020-03-03 14:10 ` Greg Kroah-Hartman
2020-03-03 14:13 ` Jann Horn
2020-03-03 14:24 ` Greg Kroah-Hartman
2020-03-03 15:44 ` Jens Axboe
2020-03-03 16:37 ` Greg Kroah-Hartman
2020-03-03 16:51 ` Jeff Layton
2020-03-03 16:55 ` Jens Axboe
2020-03-03 19:02 ` Jeff Layton
2020-03-03 19:07 ` Jens Axboe
2020-03-03 19:23 ` Jens Axboe
2020-03-03 19:43 ` Jeff Layton
2020-03-03 20:33 ` Jens Axboe
2020-03-03 21:03 ` Jeff Layton
2020-03-03 21:20 ` Jens Axboe
2020-03-03 14:10 ` Miklos Szeredi
2020-03-03 14:29 ` Greg Kroah-Hartman
2020-03-03 14:40 ` Jann Horn
2020-03-03 16:51 ` Greg Kroah-Hartman
2020-03-03 16:57 ` Jann Horn
2020-03-03 20:15 ` Greg Kroah-Hartman
2020-03-03 14:40 ` David Howells
2020-03-04 4:20 ` Ian Kent
2020-03-03 14:19 ` David Howells
2020-03-03 16:59 ` Greg Kroah-Hartman
2020-03-03 14:23 ` Christian Brauner
2020-03-03 15:23 ` Greg Kroah-Hartman
2020-03-03 15:53 ` David Howells
2020-03-04 2:01 ` Ian Kent
2020-03-04 15:22 ` Karel Zak
2020-03-04 16:49 ` Greg Kroah-Hartman
2020-03-04 17:55 ` Karel Zak
2020-03-03 14:09 ` David Howells
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