From: David Howells <dhowells@redhat.com>
To: viro@zeniv.linux.org.uk
Cc: torvalds@linux-foundation.org, dhowells@redhat.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 33/33] vfs: Add a sample program for the new mount API [ver #11]
Date: Wed, 01 Aug 2018 16:27:49 +0100 [thread overview]
Message-ID: <153313726964.13253.5202020232694227661.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <153313703562.13253.5766498657900728120.stgit@warthog.procyon.org.uk>
Add a sample program to demonstrate fsopen/fsmount/move_mount to mount
something.
Signed-off-by: David Howells <dhowells@redhat.com>
---
samples/Kconfig | 6 ++
samples/Makefile | 2 -
samples/mount_api/Makefile | 7 ++
samples/mount_api/test-fsmount.c | 118 ++++++++++++++++++++++++++++++++++++++
4 files changed, 132 insertions(+), 1 deletion(-)
create mode 100644 samples/mount_api/Makefile
create mode 100644 samples/mount_api/test-fsmount.c
diff --git a/samples/Kconfig b/samples/Kconfig
index bd133efc1a56..daa17e9f3197 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -152,4 +152,10 @@ config SAMPLE_STATX
help
Build example userspace program to use the new extended-stat syscall.
+config SAMPLE_MOUNT_API
+ bool "Build example code using the new mount API"
+ depends on BROKEN
+ help
+ Build example userspace program(s) that use the new mount API.
+
endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
index bd601c038b86..31d08cc71a5c 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -3,4 +3,4 @@
obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ trace_events/ livepatch/ \
hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/ \
configfs/ connector/ v4l/ trace_printk/ \
- vfio-mdev/ statx/ qmi/
+ vfio-mdev/ statx/ qmi/ mount_api/
diff --git a/samples/mount_api/Makefile b/samples/mount_api/Makefile
new file mode 100644
index 000000000000..6856df236dbf
--- /dev/null
+++ b/samples/mount_api/Makefile
@@ -0,0 +1,7 @@
+# List of programs to build
+hostprogs-$(CONFIG_SAMPLE_MOUNT_API) := test-fsmount
+
+# Tell kbuild to always build the programs
+always := $(hostprogs-y)
+
+HOSTCFLAGS_test-fsmount.o += -I$(objtree)/usr/include
diff --git a/samples/mount_api/test-fsmount.c b/samples/mount_api/test-fsmount.c
new file mode 100644
index 000000000000..74124025ade0
--- /dev/null
+++ b/samples/mount_api/test-fsmount.c
@@ -0,0 +1,118 @@
+/* fd-based mount test.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <linux/fs.h>
+#include <linux/unistd.h>
+
+#define E(x) do { if ((x) == -1) { perror(#x); exit(1); } } while(0)
+
+static void check_messages(int fd)
+{
+ char buf[4096];
+ int err, n;
+
+ err = errno;
+
+ for (;;) {
+ n = read(fd, buf, sizeof(buf));
+ if (n < 0)
+ break;
+ n -= 2;
+
+ switch (buf[0]) {
+ case 'e':
+ fprintf(stderr, "Error: %*.*s\n", n, n, buf + 2);
+ break;
+ case 'w':
+ fprintf(stderr, "Warning: %*.*s\n", n, n, buf + 2);
+ break;
+ case 'i':
+ fprintf(stderr, "Info: %*.*s\n", n, n, buf + 2);
+ break;
+ }
+ }
+
+ errno = err;
+}
+
+static __attribute__((noreturn))
+void mount_error(int fd, const char *s)
+{
+ check_messages(fd);
+ fprintf(stderr, "%s: %m\n", s);
+ exit(1);
+}
+
+static inline int fsopen(const char *fs_name, unsigned int flags)
+{
+ return syscall(__NR_fsopen, fs_name, flags);
+}
+
+static inline int fsmount(int fsfd, unsigned int flags, unsigned int ms_flags)
+{
+ return syscall(__NR_fsmount, fsfd, flags, ms_flags);
+}
+
+static inline int fsconfig(int fsfd, unsigned int cmd,
+ const char *key, const void *val, int aux)
+{
+ return syscall(__NR_fsconfig, fsfd, cmd, key, val, aux);
+}
+
+static inline int move_mount(int from_dfd, const char *from_pathname,
+ int to_dfd, const char *to_pathname,
+ unsigned int flags)
+{
+ return syscall(__NR_move_mount,
+ from_dfd, from_pathname,
+ to_dfd, to_pathname, flags);
+}
+
+#define E_fsconfig(fd, cmd, key, val, aux) \
+ do { \
+ if (fsconfig(fd, cmd, key, val, aux) == -1) \
+ mount_error(fd, key ?: "create"); \
+ } while (0)
+
+int main(int argc, char *argv[])
+{
+ int fsfd, mfd;
+
+ /* Mount a publically available AFS filesystem */
+ fsfd = fsopen("afs", 0);
+ if (fsfd == -1) {
+ perror("fsopen");
+ exit(1);
+ }
+
+ E_fsconfig(fsfd, FSCONFIG_SET_STRING, "source", "#grand.central.org:root.cell.", 0);
+ E_fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0);
+
+ mfd = fsmount(fsfd, 0, MS_RDONLY);
+ if (mfd < 0)
+ mount_error(fsfd, "fsmount");
+ E(close(fsfd));
+
+ if (move_mount(mfd, "", AT_FDCWD, "/mnt", MOVE_MOUNT_F_EMPTY_PATH) < 0) {
+ perror("move_mount");
+ exit(1);
+ }
+
+ E(close(mfd));
+ exit(0);
+}
next prev parent reply other threads:[~2018-08-01 17:14 UTC|newest]
Thread overview: 116+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-01 15:23 [PATCH 00/33] VFS: Introduce filesystem context [ver #11] David Howells
2018-08-01 15:24 ` [PATCH 01/33] vfs: syscall: Add open_tree(2) to reference or clone a mount " David Howells
2018-08-02 17:31 ` Alan Jenkins
2018-08-02 21:29 ` Al Viro
2018-08-02 21:51 ` David Howells
2018-08-02 23:46 ` Alan Jenkins
2018-08-01 15:24 ` [PATCH 02/33] vfs: syscall: Add move_mount(2) to move mounts around " David Howells
2018-08-01 15:24 ` [PATCH 03/33] teach move_mount(2) to work with OPEN_TREE_CLONE " David Howells
2018-10-12 14:25 ` Alan Jenkins
2018-08-01 15:24 ` [PATCH 04/33] vfs: Suppress MS_* flag defs within the kernel unless explicitly enabled " David Howells
2018-08-01 15:24 ` [PATCH 05/33] vfs: Introduce the basic header for the new mount API's filesystem context " David Howells
2018-08-01 15:24 ` [PATCH 06/33] vfs: Introduce logging functions " David Howells
2018-08-01 15:24 ` [PATCH 07/33] vfs: Add configuration parser helpers " David Howells
2018-08-01 15:24 ` [PATCH 08/33] vfs: Add LSM hooks for the new mount API " David Howells
2018-08-01 20:50 ` James Morris
2018-08-01 22:53 ` David Howells
2018-08-01 15:25 ` [PATCH 09/33] selinux: Implement the new mount API LSM hooks " David Howells
2018-08-01 15:25 ` [PATCH 10/33] smack: Implement filesystem context security " David Howells
2018-08-01 15:25 ` [PATCH 11/33] apparmor: Implement security hooks for the new mount API " David Howells
2018-08-01 15:25 ` [PATCH 12/33] tomoyo: " David Howells
2018-08-01 15:25 ` [PATCH 13/33] vfs: Separate changing mount flags full remount " David Howells
2018-08-01 15:25 ` [PATCH 14/33] vfs: Implement a filesystem superblock creation/configuration context " David Howells
2018-09-11 17:46 ` Guenter Roeck
2018-09-11 21:52 ` David Howells
2018-09-11 22:07 ` Guenter Roeck
2018-09-11 23:17 ` David Howells
2018-09-11 23:54 ` Guenter Roeck
2018-09-18 9:07 ` Sergey Senozhatsky
2018-09-18 9:40 ` Sergey Senozhatsky
2018-09-18 14:06 ` Guenter Roeck
2018-09-19 1:12 ` Sergey Senozhatsky
2018-09-19 1:26 ` Sergey Senozhatsky
2018-09-18 15:34 ` David Howells
2018-09-18 16:39 ` David Howells
2018-09-19 1:15 ` Sergey Senozhatsky
2018-09-18 17:43 ` David Howells
2018-09-18 9:54 ` Sergey Senozhatsky
2018-09-18 15:28 ` David Howells
2018-08-01 15:25 ` [PATCH 15/33] vfs: Remove unused code after filesystem context changes " David Howells
2018-08-01 15:25 ` [PATCH 16/33] procfs: Move proc_fill_super() to fs/proc/root.c " David Howells
2018-08-01 15:26 ` [PATCH 17/33] proc: Add fs_context support to procfs " David Howells
2018-08-01 15:26 ` [PATCH 18/33] ipc: Convert mqueue fs to fs_context " David Howells
2018-08-01 15:26 ` [PATCH 19/33] cpuset: Use " David Howells
2018-08-01 15:26 ` [PATCH 20/33] kernfs, sysfs, cgroup, intel_rdt: Support " David Howells
2018-08-01 15:26 ` [PATCH 21/33] hugetlbfs: Convert to " David Howells
2018-08-01 15:26 ` [PATCH 22/33] vfs: Remove kern_mount_data() " David Howells
2018-08-01 15:26 ` [PATCH 23/33] vfs: Provide documentation for new mount API " David Howells
2018-08-01 15:26 ` [PATCH 24/33] Make anon_inodes unconditional " David Howells
2018-08-01 15:26 ` [PATCH 25/33] vfs: syscall: Add fsopen() to prepare for superblock creation " David Howells
2018-08-01 15:27 ` [PATCH 26/33] vfs: Implement logging through fs_context " David Howells
2018-08-01 15:27 ` [PATCH 27/33] vfs: Add some logging to the core users of the fs_context log " David Howells
2018-08-01 15:27 ` [PATCH 28/33] vfs: syscall: Add fsconfig() for configuring and managing a context " David Howells
2018-08-06 17:28 ` Eric W. Biederman
2018-08-09 14:14 ` David Howells
2018-08-09 14:24 ` David Howells
2018-08-09 14:35 ` Miklos Szeredi
2018-08-09 15:32 ` Eric W. Biederman
2018-08-09 16:33 ` David Howells
2018-08-11 20:20 ` David Howells
2018-08-11 23:26 ` Andy Lutomirski
2018-08-01 15:27 ` [PATCH 29/33] vfs: syscall: Add fsmount() to create a mount for a superblock " David Howells
2018-08-01 15:27 ` [PATCH 30/33] vfs: syscall: Add fspick() to select a superblock for reconfiguration " David Howells
2018-08-24 14:51 ` Miklos Szeredi
2018-08-24 14:54 ` Andy Lutomirski
2018-08-01 15:27 ` [PATCH 31/33] afs: Add fs_context support " David Howells
2018-08-01 15:27 ` [PATCH 32/33] afs: Use fs_context to pass parameters over automount " David Howells
2018-08-01 15:27 ` David Howells [this message]
2018-08-10 14:05 ` BUG: Mount ignores mount options Eric W. Biederman
2018-08-10 14:36 ` Andy Lutomirski
2018-08-10 15:17 ` Eric W. Biederman
2018-08-10 15:24 ` Al Viro
2018-08-10 15:11 ` Tetsuo Handa
2018-08-10 15:13 ` David Howells
2018-08-10 15:16 ` Al Viro
2018-08-11 1:05 ` Eric W. Biederman
2018-08-11 1:46 ` Theodore Y. Ts'o
2018-08-11 4:48 ` Eric W. Biederman
2018-08-11 17:47 ` Casey Schaufler
2018-08-15 4:03 ` Eric W. Biederman
2018-08-11 1:58 ` Al Viro
2018-08-11 2:17 ` Al Viro
2018-08-11 4:43 ` Eric W. Biederman
2018-08-13 12:54 ` Miklos Szeredi
2018-08-10 15:11 ` David Howells
2018-08-10 15:39 ` Theodore Y. Ts'o
2018-08-10 15:55 ` Casey Schaufler
2018-08-10 16:11 ` David Howells
2018-08-10 18:00 ` Eric W. Biederman
2018-08-10 15:53 ` David Howells
2018-08-10 16:14 ` Theodore Y. Ts'o
2018-08-10 20:06 ` Andy Lutomirski
2018-08-10 20:46 ` Theodore Y. Ts'o
2018-08-10 22:12 ` Darrick J. Wong
2018-08-10 23:54 ` Theodore Y. Ts'o
2018-08-11 0:38 ` Darrick J. Wong
2018-08-11 1:32 ` Eric W. Biederman
2018-08-13 16:35 ` Alan Cox
2018-08-13 16:48 ` Andy Lutomirski
2018-08-13 17:29 ` Al Viro
2018-08-13 19:00 ` James Morris
2018-08-13 19:20 ` Casey Schaufler
2018-08-15 23:29 ` Serge E. Hallyn
2018-08-11 0:28 ` Eric W. Biederman
2018-08-11 1:19 ` Eric W. Biederman
2018-08-11 7:29 ` David Howells
2018-08-11 16:31 ` Andy Lutomirski
2018-08-11 16:51 ` Al Viro
2018-08-15 16:31 ` Should we split the network filesystem setup into two phases? David Howells
2018-08-15 16:51 ` Andy Lutomirski
2018-08-16 3:51 ` Steve French
2018-08-16 5:06 ` Eric W. Biederman
2018-08-16 16:24 ` Steve French
2018-08-16 17:21 ` Eric W. Biederman
2018-08-16 17:23 ` Aurélien Aptel
2018-08-16 18:36 ` Steve French
2018-08-17 23:11 ` Al Viro
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