On Fri, Aug 10, 2018 at 11:55:30PM +0100, David Howells wrote:
> Andrei Vagin <avagin@xxxxxxxxxx> wrote:
>
> > +static const char dev[] = "s test_fsopen_123";
>
> Did you mean to prefix that with "s "?
"s " means "source" here, it is an effect of a previous version of this
interface
https://lwn.net/Articles/753473/
>
> > + if (sys_fsconfig(fsfd, FSCONFIG_SET_STRING, "source", dev, 0) < 0)
> > + return pr_err("fsconfig_set_string sets source = %s", dev);
>
> Note that it's not necessary to provide a source for /proc since it will just
> ignore it.
I haven't known this. Thanks. A sligtly updated patch is attached to
this message.
>
> Anyway, thanks for doing this!
>
> David
>
>From 0fb778c4189bc739c253d0a76830307ed6d3e1d4 Mon Sep 17 00:00:00 2001
From: Andrei Vagin <avagin@xxxxxxxxx>
Date: Mon, 6 Aug 2018 19:33:16 -0700
Subject: [PATCH] selftests: implement a test for a new mount API
Currently, a reconfigure call-back is implemented only for the proc file
system. This test creates a new mount and pid namespace and then we can
create a new proc mount instance and be sure that a host configuration
will not be affected.
Signed-off-by: Andrei Vagin <avagin@xxxxxxxxx>
---
tools/testing/selftests/fsopen/Makefile | 5 +
tools/testing/selftests/fsopen/config | 2 +
tools/testing/selftests/fsopen/fsopen.c | 132 ++++++++++++++++++++++++
3 files changed, 139 insertions(+)
create mode 100644 tools/testing/selftests/fsopen/Makefile
create mode 100644 tools/testing/selftests/fsopen/config
create mode 100644 tools/testing/selftests/fsopen/fsopen.c
diff --git a/tools/testing/selftests/fsopen/Makefile b/tools/testing/selftests/fsopen/Makefile
new file mode 100644
index 000000000000..bfb1dd015e37
--- /dev/null
+++ b/tools/testing/selftests/fsopen/Makefile
@@ -0,0 +1,5 @@
+CFLAGS = -Wall -I ../../../../usr/include $(EXTRA_CFLAGS)
+
+TEST_GEN_PROGS := fsopen
+
+include ../lib.mk
diff --git a/tools/testing/selftests/fsopen/config b/tools/testing/selftests/fsopen/config
new file mode 100644
index 000000000000..d2ced6498f5a
--- /dev/null
+++ b/tools/testing/selftests/fsopen/config
@@ -0,0 +1,2 @@
+CONFIG_PROC_FS=y
+CONFIG_PID_NS=y
diff --git a/tools/testing/selftests/fsopen/fsopen.c b/tools/testing/selftests/fsopen/fsopen.c
new file mode 100644
index 000000000000..20b75506b9f4
--- /dev/null
+++ b/tools/testing/selftests/fsopen/fsopen.c
@@ -0,0 +1,132 @@
+#define _GNU_SOURCE /* See feature_test_macros(7) */
+#include <unistd.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sched.h>
+#include <linux/fs.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+static int sys_mount(char *dev_name, char *dir_name, char *type,
+ unsigned long flags, void *data)
+{
+ return syscall(__NR_mount, dev_name, dir_name, type, flags, data);
+}
+
+static int sys_fsopen(const char *fs_name, unsigned int flags)
+{
+ return syscall(__NR_fsopen, fs_name, flags);
+}
+
+static int sys_fsmount(int fsfd, unsigned int flags, unsigned int ms_flags)
+{
+ return syscall(__NR_fsmount, fsfd, flags, ms_flags);
+}
+
+static int sys_fspick(unsigned int dirfd, const char *path, unsigned int flags)
+{
+ return syscall(__NR_fspick, dirfd, path, flags);
+}
+
+static int sys_fsconfig(int fd, unsigned int cmd, const char *key, const char *value, int aux)
+{
+ return syscall(__NR_fsconfig, fd, cmd, key, value, aux);
+}
+
+static int move_mount(int from_dfd, char *from_pathname,
+ int to_dfd, char *to_pathname, unsigned int flags)
+{
+ return syscall(__NR_move_mount, from_dfd, from_pathname, to_dfd, to_pathname, flags);
+}
+
+#define pr_perror(fmt, ...) \
+ ({ \
+ fprintf(stderr, "%s:%d:" fmt ": %m\n", \
+ __func__, __LINE__, ##__VA_ARGS__); \
+ 1; \
+ })
+
+#define pr_err(fmt, ...) \
+ ({ \
+ fprintf(stderr, "%s:%d:" fmt "\n", \
+ __func__, __LINE__, ##__VA_ARGS__); \
+ 1; \
+ })
+
+//static const char opts[] = "rw";
+static int test()
+{
+ int fsfd, fsfd2, dfd;
+ char buf[4096];
+
+ fsfd = sys_fsopen("proc", 0);
+ if (fsfd < 0)
+ return pr_perror("sys_fsopen");
+
+ if (sys_fsconfig(fsfd, FSCONFIG_SET_STRING, "abrakadabra", "0", 0) == 0)
+ return pr_err("fsconfig() didn't return an error");
+
+ if (read(fsfd, buf, sizeof(buf)) <= 0)
+ return pr_perror("Unable to get a error");
+
+ pr_err("%s", buf);
+
+ if (sys_fsconfig(fsfd, FSCONFIG_SET_STRING, "gid", "0", 0))
+ return pr_perror("sys_fsconfig sets gid=5");
+
+ if (sys_fsconfig(fsfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0) < 0)
+ return pr_perror("fsconfig_cmd_create");
+
+ dfd = sys_fsmount(fsfd, 0, 0);
+ if (dfd < 0)
+ return pr_perror("sys_fsmount");
+
+ if (move_mount(dfd, ".", AT_FDCWD, "/proc", 0))
+ return pr_perror("move_mount");
+
+ fsfd2 = sys_fspick(dfd, ".", 0);
+ if (fsfd2 < 0)
+ return pr_perror("sys_fspick");
+
+ if (sys_fsconfig(fsfd2, FSCONFIG_SET_STRING, "gid", "5", 0))
+ return pr_perror("fsconfig_set_string sets gid=5");
+
+ if (sys_fsconfig(fsfd2, FSCONFIG_CMD_RECONFIGURE, NULL, NULL, 0))
+ return pr_perror("fsconfig_cmd_reconfigure");
+
+ if (close(dfd) < 0)
+ return pr_perror("close(dfd)");
+ if (close(fsfd) < 0)
+ return pr_perror("close(fsfd)");
+ if (close(fsfd2) < 0)
+ return pr_perror("close(fsfd2)");
+
+ return 0;
+}
+
+int main()
+{
+ pid_t pid;
+ int status;
+
+ if (unshare(CLONE_NEWNS | CLONE_NEWPID))
+ return pr_perror("unshare");
+
+ if (sys_mount(NULL, "/", NULL, MS_PRIVATE | MS_REC, NULL))
+ return pr_perror("mount");
+
+ pid = fork();
+ if (pid < 0)
+ return pr_perror("fork");
+ if (pid == 0)
+ return test();
+ if (waitpid(pid, &status, 0) != pid)
+ return pr_perror("waitpid");
+ if (status)
+ return 1;
+ return 0;
+}
--
2.17.1
