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authorDavid Howells <dhowells@redhat.com>2018-11-01 23:36:32 +0000
committerAl Viro <viro@zeniv.linux.org.uk>2019-03-20 18:49:06 -0400
commitf1b5618e013af28b3c78daf424436a79674423c0 (patch)
tree7fea6c6bb8ef683b92fcabaa9e3f48ed2ec8eeb0 /samples/vfs
parentcf3cba4a429be43e5527a3f78859b1bfd9ebc5fb (diff)
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vfs: Add a sample program for the new mount API
Add a sample program to demonstrate fsopen/fsmount/move_mount to mount something. To make it compile on all arches, irrespective of whether or not syscall numbers are assigned, define the syscall number to -1 if it isn't to cause the kernel to return -ENOSYS. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'samples/vfs')
-rw-r--r--samples/vfs/Makefile10
-rw-r--r--samples/vfs/test-fsmount.c133
-rw-r--r--samples/vfs/test-statx.c267
3 files changed, 410 insertions, 0 deletions
diff --git a/samples/vfs/Makefile b/samples/vfs/Makefile
new file mode 100644
index 000000000000..4ac9690fb3c4
--- /dev/null
+++ b/samples/vfs/Makefile
@@ -0,0 +1,10 @@
+# List of programs to build
+hostprogs-$(CONFIG_SAMPLE_VFS) := \
+ test-fsmount \
+ test-statx
+
+# Tell kbuild to always build the programs
+always := $(hostprogs-y)
+
+HOSTCFLAGS_test-fsmount.o += -I$(objtree)/usr/include
+HOSTCFLAGS_test-statx.o += -I$(objtree)/usr/include
diff --git a/samples/vfs/test-fsmount.c b/samples/vfs/test-fsmount.c
new file mode 100644
index 000000000000..266d72b3dce4
--- /dev/null
+++ b/samples/vfs/test-fsmount.c
@@ -0,0 +1,133 @@
+/* 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/mount.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);
+}
+
+/* Hope -1 isn't a syscall */
+#ifndef __NR_fsopen
+#define __NR_fsopen -1
+#endif
+#ifndef __NR_fsmount
+#define __NR_fsmount -1
+#endif
+#ifndef __NR_fsconfig
+#define __NR_fsconfig -1
+#endif
+#ifndef __NR_move_mount
+#define __NR_move_mount -1
+#endif
+
+
+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, MOUNT_ATTR_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);
+}
diff --git a/samples/vfs/test-statx.c b/samples/vfs/test-statx.c
new file mode 100644
index 000000000000..e91f918e84c4
--- /dev/null
+++ b/samples/vfs/test-statx.c
@@ -0,0 +1,267 @@
+/* Test the statx() system call.
+ *
+ * Note that the output of this program is intended to look like the output of
+ * /bin/stat where possible.
+ *
+ * Copyright (C) 2015 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.
+ */
+
+#define _GNU_SOURCE
+#define _ATFILE_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <linux/stat.h>
+#include <linux/fcntl.h>
+#define statx foo
+#define statx_timestamp foo_timestamp
+#include <sys/stat.h>
+#undef statx
+#undef statx_timestamp
+
+#define AT_STATX_SYNC_TYPE 0x6000
+#define AT_STATX_SYNC_AS_STAT 0x0000
+#define AT_STATX_FORCE_SYNC 0x2000
+#define AT_STATX_DONT_SYNC 0x4000
+
+#ifndef __NR_statx
+#define __NR_statx -1
+#endif
+
+static __attribute__((unused))
+ssize_t statx(int dfd, const char *filename, unsigned flags,
+ unsigned int mask, struct statx *buffer)
+{
+ return syscall(__NR_statx, dfd, filename, flags, mask, buffer);
+}
+
+static void print_time(const char *field, struct statx_timestamp *ts)
+{
+ struct tm tm;
+ time_t tim;
+ char buffer[100];
+ int len;
+
+ tim = ts->tv_sec;
+ if (!localtime_r(&tim, &tm)) {
+ perror("localtime_r");
+ exit(1);
+ }
+ len = strftime(buffer, 100, "%F %T", &tm);
+ if (len == 0) {
+ perror("strftime");
+ exit(1);
+ }
+ printf("%s", field);
+ fwrite(buffer, 1, len, stdout);
+ printf(".%09u", ts->tv_nsec);
+ len = strftime(buffer, 100, "%z", &tm);
+ if (len == 0) {
+ perror("strftime2");
+ exit(1);
+ }
+ fwrite(buffer, 1, len, stdout);
+ printf("\n");
+}
+
+static void dump_statx(struct statx *stx)
+{
+ char buffer[256], ft = '?';
+
+ printf("results=%x\n", stx->stx_mask);
+
+ printf(" ");
+ if (stx->stx_mask & STATX_SIZE)
+ printf(" Size: %-15llu", (unsigned long long)stx->stx_size);
+ if (stx->stx_mask & STATX_BLOCKS)
+ printf(" Blocks: %-10llu", (unsigned long long)stx->stx_blocks);
+ printf(" IO Block: %-6llu", (unsigned long long)stx->stx_blksize);
+ if (stx->stx_mask & STATX_TYPE) {
+ switch (stx->stx_mode & S_IFMT) {
+ case S_IFIFO: printf(" FIFO\n"); ft = 'p'; break;
+ case S_IFCHR: printf(" character special file\n"); ft = 'c'; break;
+ case S_IFDIR: printf(" directory\n"); ft = 'd'; break;
+ case S_IFBLK: printf(" block special file\n"); ft = 'b'; break;
+ case S_IFREG: printf(" regular file\n"); ft = '-'; break;
+ case S_IFLNK: printf(" symbolic link\n"); ft = 'l'; break;
+ case S_IFSOCK: printf(" socket\n"); ft = 's'; break;
+ default:
+ printf(" unknown type (%o)\n", stx->stx_mode & S_IFMT);
+ break;
+ }
+ } else {
+ printf(" no type\n");
+ }
+
+ sprintf(buffer, "%02x:%02x", stx->stx_dev_major, stx->stx_dev_minor);
+ printf("Device: %-15s", buffer);
+ if (stx->stx_mask & STATX_INO)
+ printf(" Inode: %-11llu", (unsigned long long) stx->stx_ino);
+ if (stx->stx_mask & STATX_NLINK)
+ printf(" Links: %-5u", stx->stx_nlink);
+ if (stx->stx_mask & STATX_TYPE) {
+ switch (stx->stx_mode & S_IFMT) {
+ case S_IFBLK:
+ case S_IFCHR:
+ printf(" Device type: %u,%u",
+ stx->stx_rdev_major, stx->stx_rdev_minor);
+ break;
+ }
+ }
+ printf("\n");
+
+ if (stx->stx_mask & STATX_MODE)
+ printf("Access: (%04o/%c%c%c%c%c%c%c%c%c%c) ",
+ stx->stx_mode & 07777,
+ ft,
+ stx->stx_mode & S_IRUSR ? 'r' : '-',
+ stx->stx_mode & S_IWUSR ? 'w' : '-',
+ stx->stx_mode & S_IXUSR ? 'x' : '-',
+ stx->stx_mode & S_IRGRP ? 'r' : '-',
+ stx->stx_mode & S_IWGRP ? 'w' : '-',
+ stx->stx_mode & S_IXGRP ? 'x' : '-',
+ stx->stx_mode & S_IROTH ? 'r' : '-',
+ stx->stx_mode & S_IWOTH ? 'w' : '-',
+ stx->stx_mode & S_IXOTH ? 'x' : '-');
+ if (stx->stx_mask & STATX_UID)
+ printf("Uid: %5d ", stx->stx_uid);
+ if (stx->stx_mask & STATX_GID)
+ printf("Gid: %5d\n", stx->stx_gid);
+
+ if (stx->stx_mask & STATX_ATIME)
+ print_time("Access: ", &stx->stx_atime);
+ if (stx->stx_mask & STATX_MTIME)
+ print_time("Modify: ", &stx->stx_mtime);
+ if (stx->stx_mask & STATX_CTIME)
+ print_time("Change: ", &stx->stx_ctime);
+ if (stx->stx_mask & STATX_BTIME)
+ print_time(" Birth: ", &stx->stx_btime);
+
+ if (stx->stx_attributes_mask) {
+ unsigned char bits, mbits;
+ int loop, byte;
+
+ static char attr_representation[64 + 1] =
+ /* STATX_ATTR_ flags: */
+ "????????" /* 63-56 */
+ "????????" /* 55-48 */
+ "????????" /* 47-40 */
+ "????????" /* 39-32 */
+ "????????" /* 31-24 0x00000000-ff000000 */
+ "????????" /* 23-16 0x00000000-00ff0000 */
+ "???me???" /* 15- 8 0x00000000-0000ff00 */
+ "?dai?c??" /* 7- 0 0x00000000-000000ff */
+ ;
+
+ printf("Attributes: %016llx (",
+ (unsigned long long)stx->stx_attributes);
+ for (byte = 64 - 8; byte >= 0; byte -= 8) {
+ bits = stx->stx_attributes >> byte;
+ mbits = stx->stx_attributes_mask >> byte;
+ for (loop = 7; loop >= 0; loop--) {
+ int bit = byte + loop;
+
+ if (!(mbits & 0x80))
+ putchar('.'); /* Not supported */
+ else if (bits & 0x80)
+ putchar(attr_representation[63 - bit]);
+ else
+ putchar('-'); /* Not set */
+ bits <<= 1;
+ mbits <<= 1;
+ }
+ if (byte)
+ putchar(' ');
+ }
+ printf(")\n");
+ }
+}
+
+static void dump_hex(unsigned long long *data, int from, int to)
+{
+ unsigned offset, print_offset = 1, col = 0;
+
+ from /= 8;
+ to = (to + 7) / 8;
+
+ for (offset = from; offset < to; offset++) {
+ if (print_offset) {
+ printf("%04x: ", offset * 8);
+ print_offset = 0;
+ }
+ printf("%016llx", data[offset]);
+ col++;
+ if ((col & 3) == 0) {
+ printf("\n");
+ print_offset = 1;
+ } else {
+ printf(" ");
+ }
+ }
+
+ if (!print_offset)
+ printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+ struct statx stx;
+ int ret, raw = 0, atflag = AT_SYMLINK_NOFOLLOW;
+
+ unsigned int mask = STATX_ALL;
+
+ for (argv++; *argv; argv++) {
+ if (strcmp(*argv, "-F") == 0) {
+ atflag &= ~AT_STATX_SYNC_TYPE;
+ atflag |= AT_STATX_FORCE_SYNC;
+ continue;
+ }
+ if (strcmp(*argv, "-D") == 0) {
+ atflag &= ~AT_STATX_SYNC_TYPE;
+ atflag |= AT_STATX_DONT_SYNC;
+ continue;
+ }
+ if (strcmp(*argv, "-L") == 0) {
+ atflag &= ~AT_SYMLINK_NOFOLLOW;
+ continue;
+ }
+ if (strcmp(*argv, "-O") == 0) {
+ mask &= ~STATX_BASIC_STATS;
+ continue;
+ }
+ if (strcmp(*argv, "-A") == 0) {
+ atflag |= AT_NO_AUTOMOUNT;
+ continue;
+ }
+ if (strcmp(*argv, "-R") == 0) {
+ raw = 1;
+ continue;
+ }
+
+ memset(&stx, 0xbf, sizeof(stx));
+ ret = statx(AT_FDCWD, *argv, atflag, mask, &stx);
+ printf("statx(%s) = %d\n", *argv, ret);
+ if (ret < 0) {
+ perror(*argv);
+ exit(1);
+ }
+
+ if (raw)
+ dump_hex((unsigned long long *)&stx, 0, sizeof(stx));
+
+ dump_statx(&stx);
+ }
+ return 0;
+}